U.S. patent application number 12/880901 was filed with the patent office on 2011-01-06 for manipulating objects displayed on a display screen.
This patent application is currently assigned to MICROSOFT CORPORATION. Invention is credited to ANDREW WILSON.
Application Number | 20110001696 12/880901 |
Document ID | / |
Family ID | 27616246 |
Filed Date | 2011-01-06 |
United States Patent
Application |
20110001696 |
Kind Code |
A1 |
WILSON; ANDREW |
January 6, 2011 |
MANIPULATING OBJECTS DISPLAYED ON A DISPLAY SCREEN
Abstract
Embodiments of the present invention is directed toward
determining a location where a pointing device is directed. In one
embodiment, the method includes receiving a message at the
computing device from the pointing device. Sensor data is extracted
from the message, the sensor data comprising accelerometer data,
gyroscope data, or a combination thereof. A position of the
pointing device in three-dimensional space is identified. An
orientation of the pointing device in three-dimensional space is
identified using the sensor data. A location to which the pointing
device is directed is determined by utilizing the identified
position of the pointing device and the identified orientation of
the pointing device, and an object on a display screen at the
location where the pointing device is directed is altered.
Inventors: |
WILSON; ANDREW; (SEATTLE,
WA) |
Correspondence
Address: |
SHOOK, HARDY & BACON L.L.P.;(MICROSOFT CORPORATION)
INTELLECTUAL PROPERTY DEPARTMENT, 2555 GRAND BOULEVARD
KANSAS CITY
MO
64108-2613
US
|
Assignee: |
MICROSOFT CORPORATION
REDMOND
WA
|
Family ID: |
27616246 |
Appl. No.: |
12/880901 |
Filed: |
September 13, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12106097 |
Apr 18, 2008 |
7823089 |
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12880901 |
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|
11156873 |
Jun 17, 2005 |
7596767 |
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12106097 |
|
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10160559 |
May 31, 2002 |
7032464 |
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11156873 |
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60355368 |
Feb 7, 2002 |
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Current U.S.
Class: |
345/156 ;
382/103 |
Current CPC
Class: |
G08C 17/00 20130101;
G08C 2201/31 20130101; G06F 2203/0381 20130101; G06F 3/038
20130101; G08C 2201/32 20130101; G08C 2201/41 20130101; G06F 3/0346
20130101; G08C 2201/50 20130101 |
Class at
Publication: |
345/156 ;
382/103 |
International
Class: |
G09G 5/00 20060101
G09G005/00; G06K 9/00 20060101 G06K009/00 |
Claims
1. One or more computer-readable storage media in a computing
device, having computer-useable instructions embodied thereon for
performing a method of determining a location where a pointing
device is directed, the method comprising: receiving a message at
the computing device from the pointing device; extracting sensor
data from the message, wherein the sensor data comprises
accelerometer data, gyroscope data, or a combination thereof;
identifying a position of the pointing device in three-dimensional
space; identifying an orientation of the pointing device in
three-dimensional space using the sensor data; determining a
location to which the pointing device is directed by utilizing the
identified position of the pointing device and the identified
orientation of the pointing device; and altering an object on a
display screen at the location where the pointing device is
directed.
2. The one or more computer-readable storage media of claim 1,
wherein the step of identifying a position further comprises
receiving data at the computing device associated with one or more
infrared lights detected by a camera.
3. The one or more computer-readable storage media of claim 1,
wherein the step of identifying a position further comprises:
receiving data at the computing device associated with one or more
infrared lights detected by a camera, wherein the data describes
one or more images; and analyzing the one or more images to
identify the position.
4. The one or more computer-readable storage media of claim 1,
wherein the received message includes gyroscope data and the step
of extracting further comprises extracting the gyroscope data from
the received message.
5. The one or more computer-readable storage media of claim 1,
wherein the received message includes acceleration data and the
step of extracting further comprises extracting the acceleration
data from the received message.
6. The one or more computer-readable storage media of claim 5
further comprising receiving normalization data at the computing
device prior to receiving the message.
7. The one or more computer-readable storage media of claim 6,
wherein the step of receiving normalization data further comprises
receiving calibration data at the computing device via an output of
an accelerometer in the pointing device.
8. The one or more computer-readable storage media of claim 6,
wherein the step of identifying an orientation further comprises
identifying data associated with a motion about a x-axis, a y-axis,
and a z-axis with respect to a pre-defined coordinate system.
9. The one or more computer-readable storage media of claim 1
further comprising: identifying a new orientation of the pointing
device in three-dimensional space using new sensor data in a
subsequent message; and determining a change in orientation of the
pointing device using the orientation and the new orientation.
10. One or more computer-readable storage media in a computerized
base station, the computer-readable storage media having
computer-useable instructions embodied thereon for performing a
method of manipulating an object displayed on a display screen, the
method comprising: receiving a message at the computerized base
station, the message including orientation data; identifying
acceleration data and gyroscope data from the orientation data;
determining a motion of a pointing device in 3-dimensional space
based on the acceleration data and the gyroscope data; and
manipulating the object displayed on the display screen in
accordance with the motion of the pointing device.
11. The one or more computer-readable storage media of claim 10
further comprising: receiving button data in the message from the
pointing device; and determining from the button data, if a button
on the pointing device is selected.
12. The one or more computer-readable storage media of claim 10,
wherein the step of manipulating further comprises manipulating the
object displayed on the display screen in accordance with the
motion of the pointing device and the selection of the button.
13. The one or more computer-readable storage media of claim 10
further comprising identifying if the orientation data exceeds one
or more thresholds.
14. The one or more computer-readable storage media of claim 10,
wherein the motion of the pointing device comprises an upward
motion, a downward motion, a lateral motion, or a rotation
motion.
15. The one or more computer-readable storage media of claim 14,
wherein the rotation motion comprises rotating the pointing device
about an axis.
16. A device for manipulating an object displayed on a display
screen comprising: a transceiver, which receives a signal; a
demodulator, which demodulates the received signal; a controller,
which outputs a data message including one or more of acceleration
data or gyroscope data from the demodulated signal and information
indicating whether a button has been selected; a memory, which
stores the outputted data message; and a processor, which accesses
the memory to process the outputted data message, the processing
including a determination of a motion of a pointing device in
three-dimensional space based upon the one or more of acceleration
data or gyroscope data in the outputted data message, and wherein
the processing further includes manipulating the object displayed
on the display screen in accordance with the motion of the pointing
device.
17. The device of claim 16, wherein the processor records the one
or more acceleration data or gyroscope data in the outputted data
message if the information indicates that the button on the
pointing device has been selected.
18. The device of claim 17, wherein the memory further stores one
or more thresholds and wherein the processor further processes the
one or more thresholds and the one or more acceleration data or
gyroscope data in the outputted data message.
19. The device of claim 16, wherein the memory further stores
calibration data and wherein the processor further processes the
calibration data and the one or more acceleration data or gyroscope
data in the outputted data message in order to determine the motion
of the pointing device in three-dimensional space.
20. The device of claim 16, wherein when the processor processes
the outputted data message to determine the motion of the pointing
device in three-dimensional space, the processing includes
processing data associated with a motion about an x-axis, a y-axis,
and a z-axis with respect to a pre-defined coordinate system.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of pending U.S.
application Ser. No. 12/106,097, filed Apr. 18, 2008, which is a
continuation of U.S. application Ser. No. 11/156,873, filed Jun.
17, 2005, now U.S. Pat. No. 7,596,767, which is a continuation of
U.S. application Ser. No. 10/160,659, filed May 31, 2002, now U.S.
Pat. No. 6,990,639, which claims the benefit of U.S. Provisional
Application No. 60/355,368, filed Feb. 7, 2002, which are all
herein incorporated by reference.
TECHNICAL FIELD
[0002] The invention is related to controlling electronic
components in a ubiquitous computing environment, and more
particularly to a system and process for controlling the components
using multimodal integration in which inputs from a speech
recognition subsystem, gesture recognition subsystem employing a
wireless pointing device and pointing analysis subsystem associated
with the pointing device, are combined to determine what component
a user wants to control and what control action is desired.
BACKGROUND ART
[0003] Increasingly our environment is populated with a multitude
of intelligent devices, each specialized in function. The modern
living room, for example, typically features a television,
amplifier, DVD player, lights, and so on. In the near future, we
can look forward to these devices becoming more inter-connected,
more numerous and more specialized as part of an increasingly
complex and powerful integrated intelligent environment. This
presents a challenge in designing good user interfaces.
[0004] For example, today's living room coffee table is typically
cluttered with multiple user interfaces in the form of infrared
(IR) remote controls. Often each of these interfaces controls a
single device. Tomorrow's intelligent environment presents the
opportunity to present a single intelligent user interface (UI) to
control many such devices when they are networked. This UI device
should provide the user a natural interaction with intelligent
environments. For example, people have become quite accustomed to
pointing at a piece of electronic equipment that they want to
control, owing to the extensive use of IR remote controls. It has
become almost second nature for a person in a modern environment to
point at the object he or she wants to control, even when it is not
necessary. Take the small radio frequency (RF) key fobs that are
used to lock and unlock most automobiles in the past few years as
an example. Inevitably, a driver will point the free end of the key
fob toward the car while pressing the lock or unlock button. This
is done even though the driver could just have well pointed the fob
away from the car, or even pressed the button while still in his or
her pocket, owing to the RF nature of the device. Thus, a single UI
device, which is pointed at electronic components or some extension
thereof (e.g., a wall switch to control lighting in a room) to
control these components, would represent an example of the
aforementioned natural interaction that is desirable for such a
device.
[0005] There are some so-called "universal" remote controls on the
market that are preprogrammed with the known control protocols of a
litany of electronic components, or which are designed to learn the
command protocol of an electronic component. Typically, such
devices are limited to one transmission scheme, such as IR or RF,
and so can control only electronic components operating on that
scheme. However, it would be desirable if the electronic components
themselves were passive in that they do not have to receive and
process commands from the UI device directly, but would instead
rely solely on control inputs from the aforementioned network. In
this way, the UI device does not have to differentiate among
various electronic components, say by recognizing the component in
some manner and transmitting commands using some encoding scheme
applicable only to that component, as is the case with existing
universal remote controls.
[0006] Of course, a common control protocol could be implemented
such that all the controllable electronic components within an
environment use the same control protocol and transmission scheme.
However, this would require all the electronic components to be
customized to the protocol and transmission scheme, or to be
modified to recognize the protocol and scheme. This could add
considerably to the cost of a "single UI-controlled" environment.
It would be much more desirable if the UI device could be used to
control any networked group of new or existing electronic
components regardless of remote control protocols or transmission
schemes the components were intended to operate under.
[0007] Another current approach to controlling a variety of
different electronic components in an environment is through the
use of speech recognition technology. Essentially, a speech
recognition program is used to recognize user commands. Once
recognized the command can be acted upon by a computing system that
controls the electronic components via a network connection.
However, current speech recognition-based control systems typically
exhibit high error rates. Although speech technology can perform
well under laboratory conditions, a 20%-50% decrease in recognition
rates can be experienced when these systems are used in a normal
operating environment. This decrease in accuracy occurs for the
most part because of the unpredictable and variable noise levels
found in a normal operating setting, and the way humans alter their
speech patterns to compensate for this noise. In fact,
environmental noise is currently viewed as a primary obstacle to
the widespread commercialization of speech recognition systems.
[0008] It is noted that in the preceding paragraphs, as well as in
the remainder of this specification, the description refers to
various individual publications identified by a numeric designator
contained within a pair of brackets. For example, such a reference
may be identified by reciting, "reference [1]" or simply "[1]".
Multiple references will be identified by a pair of brackets
containing more than one designator, for example, [2, 3]. A listing
of references including the publications corresponding to each
designator can be found at the end of the Detailed Description
section.
SUMMARY
[0009] The present invention is directed toward a system and
process that controls a group of networked electronic components
regardless of any remote control protocols or transmission schemes
under which they operate. In general this is accomplish using a
multimodal integration scheme in which inputs from a speech
recognition subsystem, gesture recognition subsystem employing a
wireless pointing device and pointing analysis subsystem also
employing the pointing device, are combined to determine what
component a user wants to control and what control action is
desired.
[0010] In order to control one of the aforementioned electronic
components, the component must first be identified to the control
system. In general this can be accomplished using the pointing
system to identify the desired component by pointing at it, or by
employing speech recognition, or both. The advantage of using both
is to reinforce the selection of a particular component, even in a
noisy environment where the speech recognition system may operate
poorly. Thus, by combining inputs the overall system is made more
robust. This use of divergent inputs to reinforce the selection is
referred to as multimodal integration.
[0011] Once the object is identified, the electronic device can be
controlled by the user informing the computer in some manner what
he or she wants the device to do. This may be as simple as
instructing the computer to turn the device on or off by activating
a switch or button on the pointer. However, it is also desirable to
control devices in more complex ways than merely turning them on or
off. Thus, the user must have some way of relaying the desired
command to the computer. One such way would be through the use of
voice commands interpreted by the speech recognition subsystem.
Another way is by having the user perform certain gestures with the
pointer that the computer will recognize as particular commands.
Integrating these approaches is even better as explained
previously.
[0012] In regard to the user performing certain gestures with the
pointer to remotely convey a command, this can be accomplished in a
variety of ways. One approach involves matching a sequence of
sensor values output by the pointer and recorded over a period of
time, to stored prototype sequences each representing the output of
the sensor that would be expected if the pointer were manipulated
in a prescribed manner. This prescribed manner is the
aforementioned gesture.
[0013] The stored prototype sequences are generated in a training
phase for each electronic component it is desired to control via
gesturing. Essentially to teach a gesture to the electronic
component control system that represents a particular control
action for a particular electronic component, a user simply holds
down the pointer's button while performing the desired gesture.
Meanwhile the electronic component control process is recording
particular sensor values obtained from orientation messages
transmitted by the pointer during the time the user is performing
the gesture. The recorded sensor values represent the prototype
sequence.
[0014] During operation, the control system constantly monitors the
incoming orientation messages once an object associated with a
controllable electronic component has been selected to assess
whether the user is performing a control gesture. As mentioned
above, this gesture recognition task is accomplished by matching a
sequence of sensor values output by the pointer and recorded over a
period of time, to stored prototype sequences representing the
gestures taught to the system.
[0015] It is noted however, that a gesture made by a user during
runtime may differ from the gesture preformed to create the
prototype sequence in terms of speed or amplitude. To handle this
situation, the matching process can entails not only comparing a
prototype sequence to the recorded sensor values but also comparing
the recorded sensor values to various versions of the prototype
that are scaled up and down in amplitude and/or warped in time.
Each version of the a prototype sequence is created by applying a
scaling and/or warping factor to the prototype sequence. The
scaling factors scale each value in the prototype sequence either
up or down in amplitude. Whereas, the warping factors expand or
contract the overall prototype sequence in time. Essentially, a
list is established before initiating the matching process which
includes every combination of the scaling and warping factors
possible, including the case where one or both of the scaling and
warping factors are zero (thus corresponding to the unmodified
prototype sequence).
[0016] Given this prescribed list, each prototype sequence is
selected in turn and put through a matching procedure. This
matching procedure entails computing a similarity indicator between
the input sequence and the selected prototype sequence. The
similarity indicator can be defined in various conventional ways.
However, in tested versions of the control system, the similarity
indicator was obtained by first computing a "match score" between
corresponding time steps of the input sequence and each version of
the prototype sequence using a standard Euclidean distance
technique. The match scores are averaged and the maximum match
score is identified. This maximum match score is the aforementioned
similarity indicator for the selected prototype sequence. Thus, the
aforementioned variations in the runtime gestures are considered in
computing the similarity indicator. When a similarity indicator has
been computed for every prototype sequence it is next determined
which of the similarity indicators is the largest. The prototype
sequence associated with the largest similarity indicator is the
best match to the input sequence, and could indicate the gesture
associated with that sequence was performed. However, unless the
similarity is great enough, it might be that the pointer movements
are random and do not match any of the trained gestures. This
situation is handled by ascertaining if the similarity indicator of
the designated prototype sequence exceeds a prescribed similarity
threshold. If the similarity indicator exceeds the threshold, then
it is deemed that the user has performed the gesture associated
with that designated prototype sequence. As such, the control
action corresponding to that gesture is initiated by the host
computer. If the similarity indicator does not exceed the
threshold, no control action is initiated. The foregoing process is
repeated continuously for each block of sensor values obtained from
the incoming orientation messages having the prescribed length.
[0017] In regard to the use of simple and short duration gestures,
such as for example a single upwards or downwards motion, an
opportunity exists to employ a simplified approach to gesture
recognition. For such gestures, a recognition strategy can be
employed that looks for simple trends or peaks in one or more of
the sensor values output by the pointer. For example, pitching the
pointer up may be detected by simply thresholding the output of the
accelerometer corresponding to pitch. Clearly such an approach will
admit many false positives if run in isolation. However, in a real
system this recognition will be performed in the context on an
ongoing interaction, during which it will be clear to system (and
to the user) when a simple pitch up indicates the intent to control
a device in a particular way. For example, the system may only use
the gesture recognition results if the user is also pointing at an
object, and furthermore only if the particular gesture applies to
that particular object. In addition, the user can be required to
press and hold down the pointer's button while gesturing. Requiring
the user to depress the button while gesturing allows the system to
easily determine when a gesture begins. In other words, the system
records sensor values only after the user depresses the button, and
thus gives a natural origin from which to detect trends in sensor
values. In the context of gesturing while pointing at an object,
this process induces a local coordinate system around the object,
so that "up", "down", "left" and "right" are relative to where the
object appears to the user. For example, "up" in the context of a
standing user pointing at an object on the floor means pitching up
from a pitched down position, and so on.
[0018] As discussed above, a system employing multimodal
integration would have a distinct advantage over one system alone.
To this end, the present invention includes the integration of a
conventional speech control system into the gesture control and
pointer systems which results in a simple framework for combining
the outputs of various modalities such as pointing to target
objects and pushing the button on the pointer, pointer gestures,
and speech, to arrive at a unified interpretation that instructs a
combined environmental control system on an appropriate course of
action. This framework decomposes the desired action into a command
and referent pair. The referent can be identified using the pointer
to select an object in the environment as described previously or
using a conventional speech recognition scheme, or both. The
command may be specified by pressing the button on the pointer, or
by a pointer gesture, or by a speech recognition event, or any
combination thereof.
[0019] The identity of the referent, the desired command and the
appropriate action are all determined by the multimodal integration
of the outputs of the speech recognition system, gesture
recognition system and pointing analysis processes using a dynamic
Bayes network. Specifically, the dynamic Bayes network includes
input, referent, command and action nodes. The input nodes
correspond to the aforementioned inputs and are used to provide
state information to at least one of either the referent, command,
or action node. The states of the inputs determine the state of the
referent and command nodes, and the states of the referent and
command nodes are in turn fed into the action node, whose state
depends in part on these inputs and in part on a series of device
state input nodes. The state of the action node indicates the
action that is to be implemented to affect the referent. The
referent, command and action node states comprise probability
distributions indicating the probability that each possible
referent, command and action is the respective desired referent,
command and action.
[0020] In addition, the dynamic Bayes network preserves ambiguities
from one time step to the next while waiting for enough information
to become available to make a decision as to what referent, command
or action is intended. This is done via a temporal integration
technique in which probabilities assigned to referents and commands
in the last time step are brought forward to the current time step
and are input along with new speech, pointing and gesture inputs to
influence the probability distribution computed for the referents
and commands in the current time step. In this way the network
tends to hold a memory of a command and referent, and it is thus
unnecessary to specify the command and referent at exactly the same
moment in time. It is also noted that the input from these prior
state nodes is weighted such that their influence on the state of
the referent and command nodes decreases in proportion to the
amount of time that has past since the prior state node first
acquired its current state.
[0021] The Bayes network architecture also allows the state of
various devices to be incorporated via the aforementioned device
state input nodes. In particular, these nodes provide state
information to the action node that reflects the current condition
of an electronic component associated with the device state input
node whenever the referent node probability distribution indicates
the referent is that component. This allows, as an example, the
device state input nodes to input an indication of whether the
associated electronic component is activated or deactivated. This
can be quite useful in situations where the only action permitted
in regard to an electronic component is to turn it off if it is on,
and to turn it on if it is off. In such a situation, an explicit
command need not be determined. For example if the electronic
component is a lamp, all that need be known is that the referent is
this lamp and that it is on or off. The action of turning the lamp
on or off, as the case may be, follows directly, without the user
ever having to command the system.
DESCRIPTION OF THE DRAWINGS
[0022] The specific features, aspects, and advantages of the
present invention will become better understood with regard to the
following description, appended claims, and accompanying drawings
where:
[0023] FIG. 1 is a diagram depicting an object selection system
according to the present invention.
[0024] FIG. 2 is an image depicting one version of the wireless RF
pointer employed in the object selection system of FIG. 1, where
the case is transparent revealing the electronic component
within.
[0025] FIG. 3 is a block diagram illustrating the internal
components included in one version of the wireless RF pointer
employed in the object selection system of FIG. 1.
[0026] FIG. 4 is a flow chart diagramming a process performed by
the pointer to package and transmit orientation data messages.
[0027] FIG. 5 is a block diagram illustrating the internal
components included in one version of the RF base station employed
in the object selection system of FIG. 1.
[0028] FIG. 6 is a diagram depicting a general purpose computing
device constituting an exemplary system for implementing the host
computer of the present invention.
[0029] FIG. 7 is a flow chart diagramming an overall process for
selecting an object using the object selection system of FIG.
1.
[0030] FIG. 8 is a flow chart diagramming a process for determining
a set of magnetometer correction factors for use in deriving the
orientation of the pointer performed as part of the overall process
of FIG. 7.
[0031] FIG. 9 is a flow chart diagramming a process for determining
a set of magnetometer normalization factors for use in deriving the
orientation of the pointer performed as part of the overall process
of FIG. 7.
[0032] FIGS. 10A-B depict a flow chart diagramming the process for
deriving the orientation of the pointer performed as part of the
overall process of FIG. 7.
[0033] FIG. 11 is a timeline depicting the relative frequency of
the production of video image frames by the video cameras of the
system of FIG. 1 and the short duration flash of the IR LED of the
pointer.
[0034] FIGS. 12A-B are images respectively depicting an office at
IR frequencies from each of two IF pass-filtered video cameras,
which capture the flash of the IR LED of the pointer.
[0035] FIGS. 12C-D are difference images of the same office as
depicted in FIGS. 12A-B where FIG. 12C depicts the difference image
derived from a pair of consecutive images generated by the camera
that captured the image of FIG. 12A and where FIG. 12D depicts the
difference image derived from a pair of consecutive images
generated by the camera that captured the image of FIG. 12B. The
difference images attenuate background IR leaving the pointer's IR
LED flash as the predominant feature of the image.
[0036] FIG. 13 depicts a flow chart diagramming the process for
determining the location of the pointer performed as part of the
overall process of FIG. 7.
[0037] FIG. 14 is a flow chart diagramming a first process for
using the object selection system of FIG. 1 to model an object in
an environment, such as a room, as a Gaussian blob.
[0038] FIG. 15 is a flow chart diagramming an alternate process for
using the object selection system of FIG. 1 to model an object in
an environment as a Gaussian blob.
[0039] FIG. 16 depicts a flow chart diagramming a process for
determining what object a user is pointing at with the pointer as
part of the overall process of FIG. 7.
[0040] FIG. 17 is a flow chart diagramming a process for teaching
the system of FIG. 1 to recognize gestures performed with the
pointer that represent control actions for affecting an electronic
component corresponding to or associated with a selected
object.
[0041] FIG. 18 depicts a flow chart diagramming one process for
controlling an electronic component by performing gestures with the
pointer using the system of FIG. 1.
[0042] FIG. 19 depicts a flow chart diagramming a process for
identifying the maximum averaged match score as used in the process
of FIG. 18.
[0043] FIGS. 20A-B depict a flow chart diagramming another process
for controlling an electronic component by performing gestures with
the pointer using the system of FIG. 1
[0044] FIG. 21 is a network diagram illustrating a dynamic Bayes
network used to integrate inputs from the system of FIG. 1 (both
via pointing and gesturing), speech, past beliefs and electronic
component states to determine the desired referent and command, and
then to use these determinations, along with the component state
information, to determine an appropriate action for affecting a
selected electronic component.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0045] In the following description of the preferred embodiments of
the present invention, reference is made to the accompanying
drawings which form a part hereof, and in which is shown by way of
illustration specific embodiments in which the invention may be
practiced. It is understood that other embodiments may be utilized
and structural changes may be made without departing from the scope
of the present invention.
[0046] In general, the present electronic component control system
and process involves the integration of a unique wireless
pointer-based object selection system, a unique gesture recognition
system that employs the wireless pointer, and a conventional speech
control system to create a multimodal interface for determining
what component a user wants to control and what control action is
desired.
[0047] The pointer-based object selection system will be described
first in the sections to follow, followed by the gesture
recognition system, and finally the integration of these systems
with a conventional speech recognition system to form the present
electronic component control system.
1.0 OBJECT SELECTION USING A WIRELESS POINTER
[0048] In general, the present multimodal interface control system
requires an object selection system that is capable of allowing a
user to point a pointing device (referred to as a pointer) at an
object in the environment that is, or is associated with, an
electronic component that is controllable by the control system,
and by computing the orientation and location of the pointer in
terms of the environment's pre-defined coordinate system, can
determine that the user is pointing at the object. Any object
selection system meeting the foregoing criteria can be used. One
such system is the subject of a U.S. patent application entitled "A
SYSTEM AND PROCESS FOR SELECTING OBJECTS IN A UBIQUITOUS COMPUTING
ENVIRONMENT," having a Ser. No. 10/160,962, and a filing date of
May 31, 2002, now U.S. Pat. No. 6,982,697. Referring to FIG. 1, the
object selection system described in the application employs a
wireless pointer 10, which is pointed by a user at an object in the
surrounding environment (such as a room) that the user wishes to
affect. For example, the user might point the device 10 at a lamp
with the intention of turning the lamp on or off. The wireless
pointer 10 transmits data messages to a RF transceiver base station
12, which is in communication with a host computer 14, such as a
personal computer (PC). In tested versions of the object selection
system, communications between the base station 12 and the host
computer 14 were accomplished serially via a conventional RS232
communication interface. However, other communication interfaces
can also be employed as desired. For example, the communications
could be accomplished using a Universal System Bus (USB), or IEEE
1394 (Firewire) interface, or even a wireless interface. The base
station 12 forwards data received from the pointer 10 to the host
computer 14 when a data message is received. The host computer 14
then computes the current 3D orientation of the pointer 10 from the
aforementioned received data. The process used for this computation
will be described in detail later.
[0049] The object selection system also includes components for
determining the 3D location of the pointer 10. Both the orientation
and location of the pointer within the environment in which it is
operating are needed to determine where the user is pointing the
device. In tested embodiments of the system these components
included a pair of video cameras 16, 18 with infrared-pass filters.
These cameras 16, 18 are mounted at separate locations within the
environment such that each images the portion of the environment
where the user will be operating the pointer 10 from a different
viewpoint. A wide angle lens can be used for this purpose if
necessary. Each camera 16, 18 is also connected via any
conventional wireless or wired pathway to the host computer 14, so
as to provide image data to the host computer 14. In tested
embodiments of the system, the communication interface between the
each camera 16, 18 and the host computer 14 was accomplished using
a wired IEEE 1394 (i.e., Firewire) interface. The process by which
the 3D location of the pointer 10 is determined using the image
data provided from the cameras 16, 18 will also be discussed in
detail later.
[0050] The aforementioned wireless pointer is a small hand-held
unit that in the tested versions of the object selection system
resembled a cylindrical wand, as shown in FIG. 2. However, the
pointer can take on many other forms as well. In fact the pointer
can take on any shape that is capable of accommodating the internal
electronics and external indicator lights and actuators associated
with the device--although preferably the chosen shape should be
amenable to being pointed with a readily discernable front or
pointing end. Some examples of possible alternate shapes for the
pointer would include one resembling a remote control unit for a
stereo or television, or one resembling an automobile key fob, or
one resembling a writing pen.
[0051] In general, the wireless pointer is constructed from a case
having the desired shape, which houses a number of off-the-shelf
electronic components. Referring to the block diagram of FIG. 3,
the general configuration of these electronic components will be
described. The heart of the pointer is a PIC microcontroller 300
(e.g., a PIC 16F873 20 MHz Flash programmable microcontroller),
which is connected to several other components. For example, the
output of an accelerometer 302, which produces separate x-axis and
y-axis signals (e.g., a 2-axis MEMs accelerometer model number
ADXL202 manufactured by Analog Devices, Inc. of Norwood Mass.) is
connected to the microcontroller 300. The output of a magnetometer
304 (e.g., a 3-axis magnetoresistive permalloy film magnetometer
model number HMC1023 manufactured by Honeywell SSEC of Plymouth,
Minn.), which produces separate x, y and z axis signals, is also
connected to the microcontroller 300, as can be an optional single
axis output of a gyroscope 306 (e.g., a 1-axis piezoelectric
gyroscope model number ENC-03 manufactured by Murata Manufacturing
Co., Ltd. of Kyoto, Japan). The block representing the gyroscope in
FIG. 3 has dashed lines to indicate it is an optional
component.
[0052] There is also at least one manually-operated switch
connected to the microcontroller 300. In the tested versions of the
wireless pointer, just one switch 308 was included, although more
switches could be incorporated depending on what functions it is
desired to make available for manual activation or deactivation.
The included switch 308 is a push-button switch; however any type
of switch could be employed. In general, the switch (i.e., button)
308 is employed by the user to tell the host computer to implement
some function. The particular function will be dependent on what
part of the object selection system process is currently running on
the host computer. For example, the user might depress the button
to signal to the host computer that user is pointing at an object
he or she wishes to affect (such as turning it on or off if it is
an electrical device), when the aforementioned process is in an
object selection mode. A transceiver 310 with a small antenna 312
extending therefrom, is also connected to and controlled by the
microcontroller 300. In tested versions of the pointer, a 418 MHz,
38.4 kbps bi-directional, radio frequency transceiver was
employed.
[0053] Additionally, a pair of visible spectrum LEDs 314, 316, is
connected to the microcontroller 300. Preferably, these LEDs each
emit a different color of light. For example, one of the LEDs 314
could produce red light, and the other 316 could produce green
light. The visible spectrum LEDs 314, 316 can be used for a variety
of purposes preferably related to providing status or feedback
information to the user. In the tested versions of the object
selection system, the visible spectrum LEDs 314, 316 were
controlled by commands received from the host computer via the base
station transceiver. One example of their use involves the host
computer transmitting a command via the base station transceiver to
the pointer instructing the microcontroller 300 to illuminate the
green LED 316 when the device is being pointed at an object that
the host computer is capable of affecting, and illuminating the red
LED when it is not. In addition to the pair of visible LEDs, there
is an infrared (IR) LED 318 that is connected to and controlled by
the microcontroller 300. The IR LED can be located at the front or
pointing end of the pointer. It is noted that unless the case of
the pointer is transparent to visible and/or IR light, the LEDs
314, 316, 318 whose light emissions would be blocked are configured
to extend through the case of the pointer so as to be visible from
the outside. It is further noted that a vibration unit such as
those employed in pagers could be added to the pointer so that the
host computer could activate the unit and thereby attract the
attention of the user, without the user having to look at the
pointer.
[0054] A power supply 320 provides power to the above-described
components of the wireless pointer. In tested versions of the
pointer, this power supply 320 took the form of batteries. A
regulator in the power supply 320 converts the battery voltage to 5
volts for the electronic components of the pointer. In tested
versions of the pointer about 52 mA was used when running normally,
which decreases to 1 mA when the device is in a power saving mode
that will be discussed shortly.
[0055] Tested versions of the wireless pointer operate on a
command-response protocol between the device and the base station.
Specifically, the pointer waits for a transmission from the base
station. An incoming transmission from the base station is received
by the pointer's transceiver and sent to the microcontroller. The
microcontroller is pre-programmed with instructions to decode the
received messages and to determine if the data contains an
identifier that is assigned to the pointer and which uniquely
identifies the device. This identifier is pre-programmed into the
microcontroller. If such an identifier is found in the incoming
message, then it is deemed that the message is intended for the
pointer. It is noted that the identifier scheme allows other
devices to be contacted by the host computer via the base station.
Such devices could even include multiple pointers being operated in
the same environment, such as in an office. In the case where
multiple pointer are in use in the same environment, the object
selection process which will be discussed shortly can be running as
multiple copies (one for each pointer) on the same host computer,
or could be running on separate host computers. Of course, if there
are no other devices operating in the same environment, then the
identifier could be eliminated and every message received by the
pointer would be assumed to be for it. The remainder of the data
message received can include various commands from the host
computer, including a request to provided orientation data in a
return transmission. In tested versions of the object selection
system, a request for orientation data was transmitted 50 times per
second (i.e., a rate of 50 Hz). The microcontroller is
pre-programmed to recognize the various commands and to take
specific actions in response.
[0056] For example, in the case where an incoming data message to
the pointer includes a request for orientation data, the
microcontroller would react as follows. Referring to the flow
diagram in FIG. 4, the microcontroller first determines if the
incoming data message contains an orientation data request command
(process action 400). If not, the microcontroller performs any
other command included in the incoming data message and waits for
the next message to be received from the base station (process
action 402). If, however, the microcontroller recognizes an
orientation data request command, in process action 404 it
identifies the last-read outputs from the accelerometer,
magnetometer and optionally the gyroscope (which will hereafter
sometimes be referred to collectively as "the sensors"). These
output values, along with the identifier assigned to the pointer
(if employed), and optionally the current state of the button and
error detection data (e.g., a checksum value), are packaged by the
microcontroller into an orientation data message (process action
406). The button state is used by the host computer of the system
for various purposes, as will be discussed later. The orientation
data message is then transmitted via the pointer's transceiver to
the base station (process action 408), which passes the data on to
the host computer. The aforementioned orientation message data can
be packaged and transmitted using any appropriate RF transmission
protocol.
[0057] It is noted that while tested versions of the object
selection system used the above-described polling scheme where the
pointer provided the orientation data message in response to a
transmitted request, this need not be the case. For example,
alternately, the microcontroller of the pointer could be programmed
to package and transmit an orientation message on a prescribed
periodic basis (e.g., at a 50 Hz rate).
[0058] The aforementioned base station used in the object selection
system will now be described. In one version, the base station is a
small, stand-alone box with connections for DC power and
communications with the PC, respectively, and an external antenna.
In tested versions of the object selection system, communication
with the PC is done serially via a RS232 communication interface.
However, other communication interfaces can also be employed as
desired. For example, the PC communications could be accomplished
using a Universal System Bus (USB), or IEEE 1394 (Firewire)
interface, or even a wireless interface. The antenna is designed to
receive 418 MHz radio transmissions from the pointer.
[0059] Referring now to the block diagram of FIG. 5, the general
construction of the RF transceiver base station will be described.
The antenna 502 sends and receives data message signals. In the
case of receiving a data message from the pointer, the radio
frequency transceiver 500 demodulates the received signal for input
into a PIC microcontroller 504. The microcontroller 504 provides an
output representing the received data message each time one is
received, as will be described shortly. A communication interface
506 converts microcontroller voltage levels to levels readable by
the host computer. As indicated previously, the communication
interface in tested versions of the base station converts the
microcontroller voltage levels to RS232 voltages. Power for the
base station components is provided by power supply 508, which
could also be battery powered or take the form of a separate mains
powered AC circuit.
[0060] It is noted that while the above-described version of the
base station is a stand-alone unit, this need not be the case. The
base station could be readily integrated into the host computer
itself. For example, the base station could be configured as an
expansion card which is installed in an expansion slot of the host
computer. In such a case only the antenna need be external to the
host computer.
[0061] The base station is connected to the host computer, as
described previously. Whenever an orientation data message is
received from the pointer it is transferred to the host computer
for processing. However, before providing a description of this
processing, a brief, general description of a suitable computing
environment in which this processing may be implemented and of the
aforementioned host computer, will be described in more detail. It
is noted that this computing environment is also applicable to the
other processes used in the present electronic component control
system, which will be described shortly. FIG. 6 illustrates an
example of a suitable computing system environment 100. The
computing system environment 100 is only one example of a suitable
computing environment and is not intended to suggest any limitation
as to the scope of use or functionality of the invention. Neither
should the computing environment 100 be interpreted as having any
dependency or requirement relating to any one or combination of
components illustrated in the exemplary operating environment
100.
[0062] The object selection process is operational with numerous
other general purpose or special purpose computing system
environments or configurations. Examples of well known computing
systems, environments, and/or configurations that may be suitable
for use with the invention include, but are not limited to,
personal computers, server computers, hand-held or laptop devices,
multiprocessor systems, microprocessor-based systems, set top
boxes, programmable consumer electronics, network PCs,
minicomputers, mainframe computers, distributed computing
environments that include any of the above systems or devices, and
the like (which are collectively be referred to as computers or
computing devices herein).
[0063] The object selection process may be described in the general
context of computer-executable instructions, such as program
modules, being executed by a computer. Generally, program modules
include routines, programs, objects, components, data structures,
etc. that perform particular tasks or implement particular abstract
data types. The invention may also be practiced in distributed
computing environments where tasks are performed by remote
processing devices that are linked through a communications
network. In a distributed computing environment, program modules
may be located in both local and remote computer storage media
including memory storage devices.
[0064] With reference to FIG. 6, an exemplary system for
implementing the invention includes a general purpose computing
device in the form of a computer 110. Components of computer 110
may include, but are not limited to, a processing unit 120, a
system memory 130, and a system bus 121 that couples various system
components including the system memory to the processing unit 120.
The system bus 121 may be any of several types of bus structures
including a memory bus or memory controller, a peripheral bus, and
a local bus using any of a variety of bus architectures. By way of
example, and not limitation, such architectures include Industry
Standard Architecture (ISA) bus, Micro Channel Architecture (MCA)
bus, Enhanced ISA (EISA) bus, Video Electronics Standards
Association (VESA) local bus, and Peripheral Component Interconnect
(PCI) bus also known as Mezzanine bus.
[0065] Computer 110 typically includes a variety of computer
readable media. Computer readable media can be any available media
that can be accessed by computer 110 and includes both volatile and
nonvolatile media, removable and non-removable media. By way of
example, and not limitation, computer readable media may comprise
computer storage media and communication media. Computer storage
media includes both volatile and nonvolatile, removable and
non-removable media implemented in any method or technology for
storage of information such as computer readable instructions, data
structures, program modules or other data. Computer storage media
includes, but is not limited to, RAM, ROM, EEPROM, flash memory or
other memory technology, CD-ROM, digital versatile disks (DVD) or
other optical disk storage, magnetic cassettes, magnetic tape,
magnetic disk storage or other magnetic storage devices, or any
other medium which can be used to store the desired information and
which can be accessed by computer 110. Communication media
typically embodies computer readable instructions, data structures,
program modules or other data in a modulated data signal such as a
carrier wave or other transport mechanism and includes any
information delivery media. The term "modulated data signal" means
a signal that has one or more of its characteristics set or changed
in such a manner as to encode information in the signal. By way of
example, and not limitation, communication media includes wired
media such as a wired network or direct-wired connection, and
wireless media such as acoustic, RF, infrared and other wireless
media. Combinations of the any of the above should also be included
within the scope of computer readable media.
[0066] The system memory 130 includes computer storage media in the
form of volatile and/or nonvolatile memory such as read only memory
(ROM) 131 and random access memory (RAM) 132. A basic input/output
system 133 (BIOS), containing the basic routines that help to
transfer information between elements within computer 110, such as
during start-up, is typically stored in ROM 131. RAM 132 typically
contains data and/or program modules that are immediately
accessible to and/or presently being operated on by processing unit
120. By way of example, and not limitation, FIG. 6 illustrates
operating system 134, application programs 135, other program
modules 136, and program data 137.
[0067] The computer 110 may also include other
removable/non-removable, volatile/nonvolatile computer storage
media. By way of example only, FIG. 6 illustrates a hard disk drive
141 that reads from or writes to non-removable, nonvolatile
magnetic media, a magnetic disk drive 151 that reads from or writes
to a removable, nonvolatile magnetic disk 152, and an optical disk
drive 155 that reads from or writes to a removable, nonvolatile
optical disk 156 such as a CD ROM or other optical media. Other
removable/non-removable, volatile/nonvolatile computer storage
media that can be used in the exemplary operating environment
include, but are not limited to, magnetic tape cassettes, flash
memory cards, digital versatile disks, digital video tape, solid
state RAM, solid state ROM, and the like. The hard disk drive 141
is typically connected to the system bus 121 through a
non-removable memory interface such as interface 140, and magnetic
disk drive 151 and optical disk drive 155 are typically connected
to the system bus 121 by a removable memory interface, such as
interface 150.
[0068] The drives and their associated computer storage media
discussed above and illustrated in FIG. 6, provide storage of
computer readable instructions, data structures, program modules
and other data for the computer 110. In FIG. 6, for example, hard
disk drive 141 is illustrated as storing operating system 144,
application programs 145, other program modules 146, and program
data 147. Note that these components can either be the same as or
different from operating system 134, application programs 135,
other program modules 136, and program data 137. Operating system
144, application programs 145, other program modules 146, and
program data 147 are given different numbers here to illustrate
that, at a minimum, they are different copies. A user may enter
commands and information into the computer 110 through input
devices such as a keyboard 162 and pointer 161, commonly referred
to as a mouse, trackball or touch pad. Other input devices (not
shown) may include a microphone, joystick, game pad, satellite
dish, scanner, or the like. These and other input devices are often
connected to the processing unit 120 through a user input interface
160 that is coupled to the system bus 121, but may be connected by
other interface and bus structures, such as a parallel port, game
port or a universal serial bus (USB). A monitor 191 or other type
of display device is also connected to the system bus 121 via an
interface, such as a video interface 190. In addition to the
monitor, computers may also include other peripheral output devices
such as speakers 197 and printer 196, which may be connected
through an output peripheral interface 195. Further, a camera 163
(such as a digital/electronic still or video camera, or
film/photographic scanner) capable of capturing a sequence of
images 164 can also be included as an input device to the personal
computer 110. While just one camera is depicted, multiple cameras
could be included as input devices to the personal computer 110.
The images 164 from the one or more cameras are input into the
computer 110 via an appropriate camera interface 165. This
interface 165 is connected to the system bus 121, thereby allowing
the images to be routed to and stored in the RAM 132, or one of the
other data storage devices associated with the computer 110.
However, it is noted that image data can be input into the computer
110 from any of the aforementioned computer-readable media as well,
without requiring the use of the camera 163.
[0069] The computer 110 may operate in a networked environment
using logical connections to one or more remote computers, such as
a remote computer 180. The remote computer 180 may be a personal
computer, a server, a router, a network PC, a peer device or other
common network node, and typically includes many or all of the
elements described above relative to the computer 110, although
only a memory storage device 181 has been illustrated in FIG. 6.
The logical connections depicted in FIG. 6 include a local area
network (LAN) 171 and a wide area network (WAN) 173, but may also
include other networks. Such networking environments are
commonplace in offices, enterprise-wide computer networks,
intranets and the Internet.
[0070] When used in a LAN networking environment, the computer 110
is connected to the LAN 171 through a network interface or adapter
170. When used in a WAN networking environment, the computer 110
typically includes a modem 172 or other means for establishing
communications over the WAN 173, such as the Internet. The modem
172, which may be internal or external, may be connected to the
system bus 121 via the user input interface 160, or other
appropriate mechanism. In a networked environment, program modules
depicted relative to the computer 110, or portions thereof, may be
stored in the remote memory storage device. By way of example, and
not limitation, FIG. 6 illustrates remote application programs 185
as residing on memory device 181. It will be appreciated that the
network connections shown are exemplary and other means of
establishing a communications link between the computers may be
used.
[0071] The exemplary operating environment having now been
discussed, the remaining part of this description section will be
devoted to a description of the program modules embodying the
object selection process performed by the host computer. Generally,
referring to FIG. 7, the object selection process begins by
inputting the raw sensor readings provided in an orientation
message forwarded by the base station (process action 700). These
sensor readings are normalized (process action 702) based on
factors computed in a calibration procedure, and then combined to
derive the full 3D orientation of the pointer (process action 704).
Then, the 3D location of the pointer in the environment in which it
is operating is computed (process action 706). Once the orientation
and location of the pointer is known, the object selection process
determines what the pointer is being pointed at within the
environment (process action 708), so that the object can be
affected in some manner. The process then waits for another
orientation message to be received (process action 710) and repeats
process actions 700 through 710.
[0072] The object selection process requires a series of correction
and normalization factors to be established before it can compute
the orientation of the pointer from the raw sensor values provided
in an orientation message. These factors are computed in a
calibration procedure. The first part of this calibration procedure
involves computing correction factors for each of the outputs from
the magnetometer representing the three axes of the 3-axis device,
respectively. Correction factors are needed to relate the
magnetometer outputs, which are a measure of deviation from the
direction of the Earth's magnetic field referred to as magnetic
north (specifically the dot product of the direction each axis of
the magnetometer is pointed with the direction of magnetic north),
to the coordinate frame established for the environment in which
the pointer is operating. The coordinate frame of the environment
is arbitrary, but must be pre-defined and known to the object
selection process prior to performing the calibration procedure.
For example, if the environment is a room in a building, the
coordinate frame might be establish such that the origin is in a
corner with one axis extending vertically from the corner, and the
other two horizontally along the two walls forming the corner.
[0073] Referring to FIG. 8, the magnetometer correction factors are
computed by the user first indicating to the object selection
process that a calibration reading is being taken, such as for
instance, by the user putting the object selection process running
on the host computer into a magnetometer correction factor
calibration mode (process action 800). The user then points the
pointer in a prescribed direction within the environment, with the
device being held in a known orientation (process action 802). For
example, for the sake of the user's convenience, the pre-determined
direction might be toward a wall in the front of the room and the
known orientation horizontal, such that a line extending from the
end of the pointer intersects the front wall of the room
substantially normal to its surface. If the pre-defined coordinate
system of the environment is as described in the example above,
then the pointer would be aligned with the axes of this coordinate
system, thus simplifying the correction and normalization factor
computations. The user activates the switch on the pointer when the
device is pointed in the proper direction with the proper
orientation (process action 804). Meanwhile, the object selection
process requests the pointer provide an orientation message in the
manner discussed previously (process action 806). The object
selection process then inputs the orientation message transmitted
by the pointer to determine if the switch status indicator
indicates that the pointer's switch has been activated (process
action 808). If not, the requesting and screening procedure
continues (i.e., process actions 806 and 808 are repeated).
However, when an orientation message is received in which the
button indicator indicates the button has been depressed, then it
is deemed that the sensor readings contained therein reflect those
generated when the pointer is pointing in the aforementioned
prescribed direction and with the prescribed orientation. The
magnetometer readings contained in the orientation message reflect
the deviation of each axis of the magnetometer from magnetic north
within the environment and represent the factor by which each
subsequent reading is offset to relate the readings to the
environment's coordinate frame rather than the magnetometer axes.
As such, in process action 810, the magnetometer reading for each
axis is designated as the magnetometer correction factor for that
axis.
[0074] In addition to computing the aforementioned magnetometer
correction factors, factors for range-normalizing the magnetometer
readings are also computed in the calibration procedure.
Essentially, these normalization factors are based on the maximum
and minimum outputs that each axis of the magnetometer is capable
of producing. These values are used later in a normalization
procedure that is part of the process for determining the
orientation of the pointer. A simple way of obtaining these maximum
and minimum values is for the user to wave the pointer about while
the outputs of the magnetometer are recorded by the host computer.
Specifically, referring to FIG. 9, the user would put the object
selection process running on the host computer in a magnetometer
max/min calibration mode (process action 900), and then wave the
pointer about (process action 902). Meanwhile, the object selection
process requests the pointer to provide orientation messages in the
normal manner (process action 904). The object selection process
then inputs and records the magnetometer readings contained in each
orientation message transmitted by the pointer (process action
906). This recording procedure (and presumably the pointer waving)
continues for a prescribed period of time (e.g., about 1 minute) to
ensure the likelihood that the highest and lowest possible readings
for each axis are recorded. Once the recording procedure is
complete, the object selection process selects the highest reading
recorded for each axis of the magnetometer and designates these
levels as the maximum for that axis (process action 908).
Similarly, the host computer selects the lowest reading recorded
for each axis of the magnetometer and designates these levels as
the minimum for that axis (process action 910). Normalization
factors are then computed via standard methods and stored for each
magnetometer axis that convert the range represented by the maximum
and minimum levels to a normalized range between 1.0 and -1.0
(process action 912). These magnetometer normalization factors are
used to normalize the actual readings from the magnetometer by
converting the readings to normalized values between 1.0 and -1.0
during a normalization procedure to be discussed shortly. It is
noted that the maximum and minimum values for an axis physically
correspond to that axis of the magnetometer being directed along
magnetic north and directly away from magnetic north, respectively.
It is noted that while the foregoing waving procedure is very
simple in nature, it worked well in tested embodiments of the
object selection system and provided accurate results.
[0075] Factors for range-normalizing (in [-1,1]) the accelerometer
readings are also computed in the calibration procedure. In this
case, the normalization factors are determined using the
accelerometer output normalization procedures applicable to the
accelerometer used, such as the conventional static normalization
procedure used in tested embodiments of the object selection
process.
[0076] Once the calibration procedure is complete, the object
selection process is ready to compute the orientation of the
pointer each time an orientation data message is received by the
host computer. The orientation of the pointer is defined in terms
of its pitch, roll and yaw angle about the respective x, y and z
axes of the environment's pre-defined coordinate system. These
angles can be determined via various sensor fusion processing
schemes that essentially compute the angle from the readings from
the accelerometer and magnetometer of the pointer. Any of these
existing methods could be used, however a simplified procedure was
employed in tested versions of the object selection system. In this
simplified procedure, the yaw angle is computed using the recorded
values of the magnetometer output. Even though the magnetometer is
a 3-axis device, the pitch, roll and yaw angles cannot be computed
directly from the recorded magnetometer values contained in the
orientation data message. The angles cannot be computed directly
because the magnetometer outputs a value that is the dot-product of
the direction of each magnetometer sensor axis against the
direction of magnetic north. This information is not sufficient to
calculate the pitch, roll, and yaw of the device. However, it is
possible to use the accelerometer readings in conjunction with the
magnetometer outputs to compute the orientation. Specifically,
referring to FIGS. 10A and B, the first action in the procedure is
to normalize the magnetometer and accelerometer values received in
the orientation message using the previously computed normalization
factors to simplify the calculations (process action 1000). The
pitch and roll angles of the pointer are then computed from the
normalized x-axis and y-axis accelerometer values, respectively
(process action 1002). Specifically, the pitch
angle=-arcsin(a.sub.1), where a.sub.1 is the normalized output of
the accelerometer approximately corresponding to the rotation of
the pointer about the x-axis of the environment's coordinate
system, and the roll angle=-arcsin(a.sub.2) where a.sub.2 is the
normalized output of the accelerometer approximately corresponding
to the rotation of the pointer about the y-axis of the
environment's coordinate system. Next, these pitch and roll values
are used to refine the magnetometer readings (process action 1004).
Then, in process action 1006, the previously computed magnetometer
correction factors are applied to the refined magnetometer values.
Finally, the yaw angle is computed from the refined and corrected
magnetometer values (process action 1008).
[0077] Specifically, the range-normalized accelerometer values
representing the pitch and roll are used to establish the rotation
matrix R.sub.a1,a2,0, which represents a particular instance of the
Euler angle rotation matrix
R.sub..theta..sup.x.sub.,.theta..sup.y.sub.,.theta..sup.z that
defines the composition of rotations about the x, y and z axes of
the prescribed environmental coordinate system. Next, a 3-value
vector m is formed from the range-normalized values output by the
magnetometer. The pitch and roll then corrects the output of the
magnetometer as follows:
m.sub.corrected=R.sub..alpha.1,.alpha.2.sup.y.sub.0m (1)
Let N be the output of the magnetometer when the pointer is held at
(pitch, roll, yaw)=(0, 0, 0), as determined in the calibration
procedure. Then, project onto the ground plane and normalize as
follows:
m projected = [ 1 1 0 ] T m , N projected = [ 1 1 0 ] T N m
normalized & projected = m projected m projected , N normalized
& projected = N projected N projected ( 2 ) ##EQU00001##
And finally, the yaw angle is found as follows:
yaw=sign(m.sub.np.times.N.sub.np)cos.sup.-1(m.sub.np.sup.TN.sub.np)
(3)
[0078] The computed yaw angle, along with the pitch and roll angles
derived from the accelerometer readings, are then tentatively
designated as defining the orientation of the pointer at the time
the orientation data message was transmitted by the device (process
action 1010).
[0079] It is noted that there are a number of caveats to the
foregoing procedure. First, accelerometers only give true pitch and
roll information when the pointer is motionless. This is typically
not an issue except when the orientation computations are being
used to determine if the pointer is being pointed directly at an
object. In such cases, the problem can be avoided by relying on the
orientation information only when the device is deemed to have been
motionless when the accelerometer readings were captured. To this
end, the orientation (i.e., pitch, roll and yaw) of the pointer is
computed via the foregoing procedure for the last orientation
message received. This is then compared to the orientation computed
for the next to last orientation message received, to determine if
the orientation of the pointer has changed significantly between
the orientation messages. If the orientation of the pointer did not
change significantly, then this indicates that the pointer was
motionless prior to the transmission of the last orientation
message. If the pointer was deemed to have been motionless, then
the orientation information is used. However, if it is found that a
significant change in the orientation occurred between the last two
orientation messages received, it is deemed that the pointer was in
motion and the orientation information computed from the
last-received orientation message is ignored. Secondly, magnetic
north can be distorted unpredictably in indoor environments and in
close proximity to large metal objects. However, in practice, while
it was found that for typical indoor office environments magnetic
north did not always agree with magnetic north found outdoors, it
was found to be fairly consistent throughout a single room. Thus,
since the above-described magnetometer correction factors relate
the perceived direction of magnetic north in the environment in
which the pointer is operating to the prescribed coordinate system
of that environment, when the environment is a room, it will not
make any difference if the perceived direction of magnetic north
within the room matches that in any other room or outdoors, as the
orientation of the pointer is computed for that room only. Finally,
it should be noted that the foregoing computations will not provide
accurate results if the perceived magnetic north in the environment
happens to be co-linear to the gravity vector--a situation not
likely to occur.
[0080] The foregoing designation of the pointer's orientation is
tentative because it cannot be determined from the accelerometer
reading used to compute the roll angle whether the device was in a
right-side up, or upside-down position with respect to roll when
the accelerometer outputs were captured for the orientation data
message. Thus, the computed roll angle could be inaccurate as the
computations assumed the pointer was right-side up. Referring now
to FIG. 10B, this uncertainty can be resolved by computing the
orientation assuming the pointer is right-side up (process action
1012) and then assuming the pointer is up-side down (process action
1014). Each solution is then used to compute an estimate of what
the magnetometer outputs should be given the computed orientation
(process actions 1016 and 1018). It is then determined for each
case how close the estimated magnetometer values are to the actual
values contained in the orientation message (process actions 1020
and 1022). It is next ascertained whether the estimated
magnetometer values for the right-side up case are closer to the
actual values than the estimated value for the upside-down case
(process action 1024). If they are, then the pointer is deemed to
have been right-side up (process action 1026). If, however, it is
determined that the estimated magnetometer values for the
right-side up case are not closer to the actual values than the
estimated value for the upside-down case, then the pointer is
deemed to have been up-side down (process action 1028). It is next
determined if roll angle computed in the tentative rotation matrix
is consistent with the deemed case (process action 1030). If it is
consistent, the tentative rotation matrix is designated as the
finalized rotation matrix (process action 1034). If, however, the
tentative rotation matrix is inconsistent with the minimum error
case, then the roll angle is modified (i.e., by 180 degrees) in
process action 1032, and the modified rotation matrix is designated
as the finalized rotation matrix (process action 1034).
[0081] One way to accomplish the foregoing task is to compute the
orientation (R) as described above, except that it is computed
first assuming the pitch angle derived from the accelerometer
output reflects a right-side up orientation of the pointer, i.e.,
Pitch.sub.right-side up=-arcsin(a) where a is the normalized output
of the accelerometer approximately corresponding to the rotation of
the pointer about the x-axis of the environment's coordinate
system. The orientation is then computed assuming the pitch angle
derived from the accelerometer output reflects an up-side down
orientation of the pointer, i.e., Pitch.sub.up-side
down=-.pi.+arcsin(a). A separate estimate of what the magnetometer
outputs (m*) should be given the orientation computed for the
right-side up condition and for the up-side down condition are then
computed as follows:
m*=R.sup.TN, (4)
where N is the direction of magnetic north. m* is the estimated
magnetometer output assuming the pointer is in the right-side up
condition when R is the orientation computed assuming the pointer
was in this condition, whereas m* is the estimated magnetometer
output assuming the pointer is in the up-side down condition when R
is the orientation computed assuming the pointer was in that
condition. The error between the estimated magnetometer outputs
(m*) and the actual magnetometer outputs (m) is next computed for
both conditions, where the error is defined as (m*-m).sup.T (m*-m).
The pointer orientation associated with the lesser of the two error
values computed is deemed to be the actual orientation of the
pointer. It is noted that the roll angle derived from the
accelerometer output could be used to perform as similar error
analysis and determine the actual orientation of the pointer.
[0082] It is further noted that the 2-axis accelerometer used in
the tested versions of the pointer could be replaced with a more
complex 3-axis accelerometer, or an additional 1-axis accelerometer
or mercury switch oriented in the appropriate direction could be
employed, to eliminate the need for the foregoing error computation
procedure. This would be possible because it can be determined
directly from the "third"-axis readout whether the pointer was
right-side up or upside-down with respect to roll. However, this
change would add to the complexity of the pointer and must be
weighed against the relatively minimal cost of the added processing
required to do the error computation procedure.
[0083] As indicated previously, both the orientation and location
of the pointer within the environment in which it is operating are
needed to determine where the user is pointing the device. The
position of the pointer within the environment can be determined
via various methods, such as using conventional computer vision
techniques [1] or ultrasonic acoustic locating systems [2, 3].
While these methods, and their like, could be used successfully,
they are relatively complex and often require an expensive
infrastructure to implement. A simpler, less costly process was
developed for tested versions of the system and will now be
described. Specifically, the position of the pointer within the
environment is determined with the aid of the two video camera
having IR-pass filters. The cameras are calibrated ahead of time to
the environment's coordinate system using conventional calibration
methods to establish the camera parameters (both intrinsic and
extrinsic) that will be needed to determine the 3D position of the
pointing end of the pointer from images captured by the cameras. In
operation, the aforementioned IR LED of the pointer is flashed for
approximately 3 milliseconds at a rate of approximately 15 Hz by
the device's microcontroller. Simultaneously, both cameras are
recording the scene at 30 Hz. This means that the IR light in the
environment is captured in 1/30.sup.th of a second exposures to
produce each frame of the video sequence produced each camera.
Referring to the time line depicted in FIG. 11, it can be seen that
the flash of the IR LED will be captured in every other frame of
the video sequence produced by each camera due to the approximately
15 Hz flashing rate. Referring now to FIGS. 12 A and B, images
depicting the scene at IR frequencies and capturing the flash from
the pointer are shown, as produced contemporaneously from each
camera. As can be seen, the IR LED flash appears as a bright spot
against a background lower intensity IR noise. Referring now to
FIG. 13, the procedure for ascertaining the location to the pointer
in terms of the pre-defined coordinate system of the environment
will be described. First, the image coordinates of the IR LED flash
are determined in each contemporaneously captured frame from the
cameras that depicts the flash. This is accomplished by first
performing a standard subtraction process on a contemporaneously
produced pair of frames from each of the cameras (process action
1300). The resulting difference images represent the scene with
most of the background IR eliminated and the IR LED flash the
predominant feature in terms of intensity in the images, as shown
in FIGS. 12 C and D which depict the scene from the cameras
captured in the image of FIGS. 12 A & B respectively once the
background IR is eliminated via the subtraction method. A standard
peak detection procedure is then performed on the difference image
computed from each pair of frames produced by each of the cameras
(process action 1302). This peak detection procedure identifies the
pixel in the difference image exhibiting the highest intensity. The
image coordinates of this pixel are deemed to represent the
location of the pointer in the image (process action 1304). Once
the image coordinates of the pointer (as represented by the IF LED)
are computed from a pair of images produced contemporaneously by
each camera, standard stereo image techniques (typically involving
triangulation) are employed to determine the 3D location of the
pointer in the environment (process action 1306).
[0084] Once the pointer's location and orientation at a given point
in time are known it is possible to determine where the user is
pointing in anticipation of affecting an object in the vicinity.
There are numerous methods that can be used to determine the
pointed-to location and to identify the object at or near that
location. In tested versions of the system, a Gaussian blob scheme
is employed to accomplish the foregoing task. This entails first
modeling all the objects in the environment that it is desired for
the user to be able to affect by pointing at it with the pointer,
as 3D Gaussian blobs. In other words, the location and extent of
the object is modeled as a single 3D Gaussian blob defined by the
coordinates of a 3D location in the environment representing the
mean .mu. of the blob and a covariance .SIGMA. defining the outside
edge of the blob. These multivariate Gaussians are probability
distributions that are easily learned from data, and can coarsely
represent an object of a given size and orientation.
[0085] The modeling of the objects of interest in the environment
as Gaussian blobs can be accomplished in any conventional manner.
In tested versions of the object selection system, two different
methods were employed. Referring to FIG. 14, the first involves the
user initiating a target training procedure that is part of the
object selection process (process action 1400), and then holding
the button on the pointer down as he or she traces the outline of
the object (process action 1402). In addition, the user enters
information into the process that identifies the object being
traced (process action 1404). Meanwhile, the target training
procedure causes a request to be sent to the pointer directing it
to provide an orientation message in the manner described
previously (process action 1406). The orientation message
transmitted by the pointer is inputted (process action 1408), and
it is determined whether the button state indicator included in the
message indicates that the pointer's button is activated (process
action 1410). If not, process actions 1406 through 1410 are
repeated. When, it is discovered that the button state indicator
indicates the button is activated, then in process action 1412, the
location of the pointer (as represented by the IR LED) is computed
and recorded in the manner described above using the output from
the video cameras. Next, a request is sent to the pointer directing
it to provide an orientation message, and it is input when received
(process action 1414). It is then determined whether the button
state indicator still indicates that the pointer's button is
activated (process action 1416). If so, process actions 1412
through 1416 are repeated. If, however, it is discovered that the
button state indicator indicates the button is no longer activated,
then it is deemed that the user has completed the tracing task and
in process action 1418, a Gaussian blob is defined for the series
of locations recorded during the tracing. Specifically, for
recorded locations x.sub.i, the mean and covariance of the these
points is computed as follows:
.mu. = 1 n i x i .SIGMA. = 1 n i ( x i - .mu. ) ( x i - .mu. ) T (
5 ) ##EQU00002##
The computed mean and covariance define the Gaussian blob
representing the traced object. This procedure can then be repeated
for each object of interest in the environment.
[0086] An alternate, albeit somewhat more complex, method to model
the objects of interest in the environment as Gaussian blobs was
also employed in tested versions of the object selection process.
This method has particular advantage when an object of interest is
out of the line of sight of one or both of the cameras, such as if
it were located near a wall below one of the cameras. Since images
of the object from both cameras are needed to compute the pointers
location, and so the points x.sub.i in the tracing procedure, the
previously described target training method cannot be used unless
both of the cameras can "see" the object.
[0087] Referring to FIG. 15, this second target training method
involves the user first initiating the training procedure (process
action 1500), and then entering information identifying the object
to be modeled (process action 1502). The user then repeatedly
(i.e., at least twice) points at the object being modeled with the
pointer and depresses the device's button, each time from a
different position in the environment within the line of sight of
both cameras (process action 1504). When the user completes the
foregoing action at the last pointing location, he or she informs
the host computer that the pointing procedure is complete (process
action 1506). Meanwhile, the training procedure causes a request to
be sent to the pointer directing it to provide an orientation
message in the manner described previously (process action 1508).
The orientation message transmitted by the pointer is inputted
(process action 1510), and it is determined whether the button
state indicator included in the message indicates that the
pointer's button is activated (process action 1512). If not,
process actions 1508 through 1512 are repeated. When, it is
discovered that the button state indicator indicates the button is
activated, then in process action 1514, the orientation and
location of the pointer are computed and recorded using the
procedures described previously. It is next determined if the user
has indicated that the pointing procedure is complete (process
action 1516). If not, process actions 1508 through 1516 are then
repeated as appropriate. If, however, the pointing procedure is
complete, a ray that projects through the environment from the
pointer's location along the device's orientation direction is
established for each recorded pointing location (process action
1518). Next, the coordinates of the point in the environment
representing the mean of a Gaussian blob that is to be used to
model the object under consideration, are computed (process action
1520). This is preferably accomplished as follows. For each
pointing location:
x.sub.i+s.sub.iw.sub.i=.mu. (6)
where x.sub.i is the position of the pointer at the i.sup.th
pointing location, w.sub.i is the ray extending in the direction
the pointer is pointed from the i.sup.th pointing location, and
s.sub.i is an unknown distance to the target object. This defines a
linear system of equations that can be solved via a conventional
least squares procedure to find the mean location that best fits
the data.
[0088] The covariance of the Gaussian blob representing the object
being modeled is then established (process action 1522). This can
be done in a number of ways. First, the covariance could be
prescribed or user entered. However, in tested versions of the
target training procedure, the covariance of the target object was
computed by adding a minimum covariance to the spread of the
intersection points, as follows:
.SIGMA.=.SIGMA..sub.0+(x.sub.i+s.sub.iw.sub.i-.mu.)(x.sub.i+s.sub.iw.sub-
.i-.mu.).sup.T (7)
[0089] It is noted that the aforementioned computations do not take
into account that the accuracy in pointing with the pointer is
related to the angular error in the calculation of the device's
orientation (and so in the ray w.sub.i). Thus, a computed pointing
location that is far away from the object being modeled is
inherently more uncertain than a computed pointing location which
is nearby the target. Accordingly, the foregoing target training
procedure can be refined by discounting the more remote pointing
location to some degree in defining the Gaussian blob representing
an object being modeled. This can be accomplished using a weighted
least squares approach, as follows:
W i ( x i + s i w i ) = W i .mu. W i = ( 1 c s ^ i + .eta. ) 2 I (
8 ) ##EQU00003##
where W.sub.i is the weight assigned to the i.sup.th pointing
location, s.sub.i is an estimate of the distance to the target
object, possibly computed using the previous procedure employing
the non-weighted least squares approach, c and .eta. are parameters
related to the angular error of the pointer, and I is the identity
matrix. As before, Eq. (8) is generated for each pointing location
to define a linear system of equations that can be solved via the
least squares procedure to find the mean location that best fits
the data, but this time taking into consideration the angular error
associated with the computed orientation of the pointer.
[0090] It is noted that the foregoing procedures for computing the
mean and covariance of a Gaussian blob representing an object allow
the represented shape of the object to be modified by simply adding
any number of pointing locations where the pointer is pointed along
the body of the target object.
[0091] Once a Gaussian blob for each object of interest in the
environment has been defined, and stored in the memory of the host
computer, the pointer can be used to select an object by simply
pointing at it. The user can then affect the object, as mentioned
previously. However, first, the processes that allow a user to
select a modeled object in the environment using the pointer will
be described. These processes are preformed each time the host
computer receives an orientation message from the pointer.
[0092] One simple technique for selecting a modeled object is to
evaluate the Gaussian distribution at a point nearest the mean of
each Gaussian representing an object of interest in the environment
which is intersected by the a ray cast by the pointer, along that
ray. The likelihood that the pointer is being pointed a modeled
object i is then:
l.sub.i=g(x+.parallel..mu..sub.i-x.parallel.w,.SIGMA..sub.i)
(9)
where x is the position of the pointer (as represented by the IR
LED), w is a ray extending from x in the direction the pointer is
pointed, and g(.mu.,.SIGMA.) is the probability distribution
function of the multivariate Gaussian. The object associated with
the Gaussian blob exhibiting the highest probability/can then be
designated as the selected object.
[0093] Another approach is to project each Gaussian onto a plane
normal to either w or .mu.-x, and then to take the value of the
resulting 2D Gaussian at the point where the ray w intersects the
plane. This approach can be accomplished as follows. Referring to
FIG. 16, the ray that projects through the environment from the
pointer's location along the device's orientation direction, is
established (process action 1600). In addition, a line is defined
between the mean point of each of the Gaussian blobs and the
pointer's location (process action 1602). Next, for each Gaussian
blob a plane normal to the line between the blob mean and the
pointer's location, or alternately a plane normal to the ray, is
then defined (process action 1604). Each Gaussian blob is then
projected onto the associated plane using standard methods, to
define a 2D Gaussian (process action 1606). The aforementioned ray
is also projected onto each of these planes (process action 1608).
This projection may be a point if the ray is normal to the plane or
a line if it is not normal to the plane. For each projected
Gaussian, the likelihood that the pointer is being pointed at the
associated object is computed based on how far the origin of the
projected Gaussian is from the closest point of projected ray using
standard methods (process action 1610). Essentially, the shorter
the distance between the origin of the projected Gaussian and the
closest point of projected ray, the higher the probability that the
pointer is being pointed at the object associated with the
Gaussian. Thus, in process action 1712, the Gaussian blob having
the highest probability is identified. At this point the Gaussian
blob associated with the highest probability could be designated as
the selected object. However, this could result in the nearest
object to the direction the user is pointing being selected, even
though the user may not actually be intending to select it. To
prevent this situation, a thresholding procedure can be performed.
Referring to FIG. 16 once again, this thresholding procedure
involves determining if the probability computed for the Gaussian
blob identified as having the highest probability exceeds a
prescribed threshold (process action 1614). If the computed
probability exceeds the threshold, then the object associated with
the Gaussian blob exhibiting the highest probability is designated
as being the object the user is pointing at (process action 1616).
The threshold will vary depending on the environment, but generally
should be high enough to ensure an object is actually being pointed
at and that the user is not just pointing at no particular object.
In this way, the process does not just pick the nearest object.
Thus, if it is determined the computed probability the Gaussian
blob identified as having the highest probability does not exceed
the prescribed threshold, then no object is selected and the
procedure ends. The foregoing procedure is then repeated upon
receipt of the next orientation message, as indicated previously.
It is noted that the thresholding procedure can also be applied to
the first technique for selecting a modeled object, if desired.
[0094] It is further noted that the calculation associated with the
weighted least squares approach described above can be adopted to
estimate the average angular error of the pointer without reference
to any ground truth data. This could be useful for correcting the
computed pointer orientation direction. If this were the case, then
the simpler non-weighted least squares approach could be employed
in the alternate target object training procedure, as well as
making the object selection process more accurate. The average
angular error estimation procedure requires that the pointer be
modified by the addition of a laser pointer, which is attached so
as to project a laser beam along the pointing direction of the
pointer. The user points at the object with the pointer from a
position in the environment within the line of sight of both
cameras, and depresses the device's button, as was done in the
alternate target object training procedure. In this case, this
pointing procedure is repeated multiple times at different pointing
locations with the user being careful to line up the laser on the
same spot on the surface of the target object. This eliminates any
error due to the user's pointing accuracy. The orientation and
location of the pointer at each pointing location is computed using
the procedures described previously. The average angular error is
then computed as follows:
i 1 n cos - 1 ( w T .mu. - x i .mu. - x i ) ( 10 ) ##EQU00004##
wherein i refers to the pointing location in the environment, n
refers to the total number of pointing locations, w is a ray
originating at the location of the pointing device and extending in
a direction defined by the orientation of the device, x is the
location of the pointing device, and .mu. is the location of the
mean of the Gaussian blob representing the target object
[0095] Without reference to ground truth position data, this
estimate of error is a measure of the internal accuracy and
repeatability of the pointer pointing and target object training
procedures. This measure is believed to be more related to the
overall performance of the pointer than to an estimate of the error
in absolute position and orientation of the device, which is
subject to, for instance, the calibration of the cameras to the
environment's coordinate frame.
2.0 GESTURE RECOGNITION
[0096] As described above, the orientation and position of the
pointer may be found by a combination of sensors and signal
processing techniques. This allows an object, which is an
electronic component controllable by a computer via a network
connection or an extension thereof, to be selected based on a
geometric model of the environment containing the object. The
selection of a target object is accomplished by a user merely
pointing at the object with the pointer for a moment.
[0097] Once the object is selected, the electronic device can be
controlled by the user informing the computer in some manner of
what he or she wants the device to do. As described above, this may
be as simple as instructing the computer to turn the device on or
off by activating a switch or button on the pointer. However, it is
also desirable to control device in more complex ways than merely
turning them on or off. Thus, the user must have some way of
relaying the desired command to the computer. One such way is by
having the user perform certain gestures with the pointer that the
computer will recognize as particular commands. This can be
accomplished in a variety of ways.
[0098] One approach involves matching a sequence of sensor values
output by the pointer and recorded over a period of time, to stored
prototype sequences each representing the output of one or more
sensors that would be expected if the pointer were manipulated in a
prescribed manner. This prescribed manner is the aforementioned
gesture. The stored prototype sequences are generated in a training
phase for each electronic component it is desired to control via
gesturing. To account for the fact that a gesture made by a user
during runtime may differ from the gesture performed to create the
prototype sequence in terms of speed and amplitude, the
aforementioned matching process can not only entail comparing a
prototype sequence to the recorded sensor values but also comparing
the recorded sensor values to various versions of the prototype
that are scaled up and down in amplitude and/or warped in time
(i.e., linearly stretched and contracted). The procedure used to
generate each prototype sequence associated with a particular
gesture is outlined in the flow diagram shown in FIG. 17.
Specifically, the user initiates a gesture training mode of the
electronic component control process running on the aforementioned
host computer (process action 1700). The user then inputs the
identity of the electronic component that is capable of being
controlled by the host computer and specifies the particular
control action that is to be associated with the gesture being
taught to the control system (process action 1702). Next, the user
activates the aforementioned button on the pointer and performs a
unique gesture with the pointer, which the user desires to
represent the previously specified control action for the
identified component (process action 1704). Finally, the user
deactivates (e.g., releases) the pointer's button when the gesture
is complete (process action 1706). Meanwhile, the gesture training
process causes periodic requests to be sent to the pointer
directing it to provide orientation messages in the manner
described previously (process action 1708). The process waits for
an orientation message to be received (process action 1710), and
upon receipt determines whether the switch state indicator included
in the message indicates that the pointer's button is activated
(process action 1712). If not, process actions 1710 and 1712 are
repeated. When, it is discovered that the button state indicator
indicates the button is activated, then in process action 1714, a
portion of a prototype sequence is obtained by recording prescribed
pointer sensor outputs taken from the last orientation message
received. The process waits for the next orientation message to be
received (process action 1716), and upon receipt determines whether
the switch state indicator included in the message indicates that
the pointer's switch is still activated (process action 1718). If
so, process actions 1714 through 1718 are repeated. If, however,
the switch state indicator included in the message indicates that
the pointer's switch has been deactivated, then it is deemed that
the gesture has been completed, and in process action 1720, the
recorded values are designated as the prototype sequence
representing the gesture being taught to the system (process action
1722). The foregoing procedure would be repeated for each control
gesture it is desired to teach to the component control system and
for each electronic component it is desired to control via
gesturing.
[0099] During operation, the electronic component control system
constantly monitors the incoming pointer orientation messages after
an object associated with a controllable electronic component has
been selected, to assess whether the user is performing a control
gesture applicable to that component. This gesture recognition task
is accomplished as follows. Referring to FIG. 18, particular sensor
readings obtained from incoming orientation messages are first
recorded for a prescribed period of time to create an input
sequence (process action 1800). Next, assuming more than one
control gesture has been taught to the control system for the
electronic component under consideration, a previously unselected
one of the prototype sequences representing the various gestures
applicable to the electronic component is selected (process action
1802). If only one gesture was taught to the system for the
electronic component under consideration, then the associated
prototype sequence for that gesture is selected. A similarity
indicator is then computed between the input sequence and the
selected prototype sequence (process action 1804). The similarity
indicator is a measure of the similarity between the input sequence
and the prototype sequence. This measure of similarity can be
defined in various conventional ways. In tested versions of the
control system, the similarity indicator was computed as
follows.
[0100] As mentioned above, the matching process can entail not only
comparing a prototype sequence to the recorded sensor values but
also comparing the recorded sensor values to various versions of
the prototype that are scaled up and down in amplitude and/or
warped in time. In tested versions, the amplitude scaling factors
ranged from 0.8 to 1.8 in increments of 0.2, and the time warping
factors ranged from 0.6 to 2.0 in increments of 0.2. However, while
it is believed the aforementioned scaling and warping factors are
adequate to cover any reasonable variation in the gesture
associated with a prototype sequence, it is noted that different
ranges and increments could be used to generate the scaling and
warping factors as desired. In fact the increments do not even have
to be equal across the range. In practice, the prototype sequence
is scaled up or down in amplitude by applying scaling factors to
each value in the prototype sequence. Whereas, the prototype
sequence is warped in time by applying warping factors that expand
or contract the overall sequence in time.
[0101] Essentially, a list is established before initiating the
matching process which includes every combination of the scaling
and warping factors possible, includes the case where one or both
of the scaling and warping factors are zero. Note that the instance
where both the scaling and warping factors are zero corresponds to
the case where the prototype sequence is unmodified. Given this
prescribed list, and referring now to FIG. 19, a previously
unselected scaling and warping factor combination is selected
(process action 1900). Next, in process action 1902, the prototype
sequence is scaled in amplitude and/or warped in time using the
selected factor combination to produce a current version of the
selected prototype sequence (which may be the prototype sequence
itself if the selected factor combination is zero scaling and zero
warping). A so called "match score" is computed between
corresponding time steps of the input sequence and the current
version of the prototype sequence using a standard Euclidean
distance technique (process action 1904). A time step refers to the
prescribed sensor value or values taken from the same pointer
orientation message--i.e., the value(s) captured at the same time
by the pointer. Correspondence between time steps refers to
computing the match score between the sensor values associated with
the first time step in both sequences, then the second, and so on
until the last time step of the current version of the prototype
sequence is reached. Once all the match scores have been computed
they are summed and divided by the number of time steps involved,
thereby producing an average match score (process action 1906).
Thus, the average match score f(p.sub.i(w,s),x) based on the
aforementioned Euclidean distance function f can be computed as
follows:
f ( p i ( w , s ) , x ) = 1 n t ( p i ( w , s , t ) - x ( t ) ) T (
p i ( w , s , t ) - x ( t ) ) ( 11 ) ##EQU00005##
for selected warp w and scale s, where p.sub.i(w,s,t) is the
recorded sensor value(s) at time step t of the current version of
the selected prototype sequence i, x(t) refers to the corresponding
sensor values of the input sequence at time step t, and n refers to
the length of the current version of the selected prototype
sequence p.sub.i(w,s) and so the length of x as well, The foregoing
process is then repeated for every other combination of the warp
and scale factors.
[0102] Specifically, it is determined if all the warp and scale
factor combinations from the prescribed list have been selected
(process action 1908). If not, the process actions 1900 through
1908 are repeated. Once an average match score has been computed
for every version of the prototype sequence (including the
unmodified sequence), the maximum averaged match score is
identified (process action 1910). This maximum averaged match score
is the aforementioned similarity indicator for the selected
prototype sequence.
[0103] Referring once again to FIG. 18, the similarity indicator is
then computed for each remaining prototype sequence by first
determining if there are any remaining unselected prototype
sequences (process action 1806). If so, then process actions 1802
through 1806 are repeated. When a similarity indicator has been
computed for every prototype sequence, it is next determined which
of the similarity indicators is the largest (process action 1808).
The prototype sequence associated with the largest similarity
indicator is designated as the best match to the input sequence
(process action 1810). The gesture associated with the designated
prototype sequence is the most likely of the gestures the system
has been trained for to match the pointer movements as represented
by the input sequence. However unless the similarity is great
enough, it might just be that the pointer movements are random and
do not match any of the trained gestures. This situation is handled
by ascertaining if the similarity indicator of the designated
prototype sequence exceeds a prescribed similarity threshold
(process action 1812). If the similarity indicator exceeds the
threshold, then it is deemed that the user has performed the
gesture associated with that designated prototype sequence. As
such, the gesture is identified (process action 1814), and the
control action associated with that gesture is initiated by the
host computer (process action 1816). However, if the similarity
indicator does not exceed the threshold, no control action is
initiated. The foregoing process is then repeated continuously for
each consecutive block of sensor values obtained from the incoming
orientation messages having the prescribed length for as long as
the object associated with the electronic component under
consideration remains selected.
[0104] It is noted that the aforementioned prescribed length of the
input sequence is made long enough to ensure that the
distinguishing characteristics of each gesture are captured
therein. This aids in making sure only one gesture is recognized
when several gestures are employed in the system to initiate
different control actions. In tested versions of the present system
employing the foregoing match score procedure this means making the
input sequence as long as the longest of the scaled and warped
version of the prototype sequence. The aforementioned match score
threshold is chosen similarly in that it is made large enough to
ensure that the distinguishing characteristics of a gesture as
captured in the prototype sequence actually exist in the input
sequence, and that the final match score computed for any other
prototype sequence associated with another gesture not having these
distinguishing characteristics will not exceed the threshold.
[0105] As to the specific sensor output or outputs that are used to
construct the prototype sequences and the input sequence, any
combination of the accelerometer, magnetometer and gyroscope
outputs contained in each orientation message can be employed. It
should be noted however, that the accelerometer will not provide an
output indicative of the change in the yaw angle of the pointer,
and the gyroscope will only provide data reflecting a change in the
yaw angle of the pointer. Thus, the user could be restricted in the
types of motion he or she is allowed to use in creating gesture if
just the accelerometer or gyroscope outputs are employed in the
aforementioned sequences. Using fewer output values to characterize
the gesture could result in lower processing costs in comparing the
prototype and input sequences. However, to give the user complete
freedom in choosing the types of motion used to define a gesture,
both the accelerometer and gyroscope outputs, or the magnetometer
outputs, would have to be included in the sequences. In addition,
while the processing costs would be higher, using the outputs from
all three sensors could provide better accuracy in characterizing
the gesture motions.
[0106] The foregoing prototype matching approach has the advantage
of allowing the electronic component control system to be trained
to recognized gestures choreographed by the user, rather than
requiring prescribed gestures to be used. In addition, the user can
make the gesture as simple or as complex as he or she desires. A
drawback of this approach however is that runtime variations of the
gesture may involve more than simple scaling of amplitude and
linear time warps. Pattern recognition techniques that incorporate
multiple training examples, such as hidden Markov models (HMMs)
[8], may capture other important variations that may be seen in
runtime. However, such techniques model only those variations
present in the training data, and so would require the user to
perform the desired gesture over and over during the training
process--perhaps to the point of making the procedure unacceptably
tedious. In addition, for gestures having a short duration, HMMs
often give many false positives due to their nonlinear time warping
abilities. Thus, the use of a HMM approach should be limited to
user-created gestures having longer durations.
[0107] In regard to the use of simple and short duration gestures,
such as for example a single motion up, down or to either side, an
opportunity exists to employ a simplified and perhaps more robust
approach to gesture recognition. For such gestures, a recognition
strategy can be employed that looks for trends or peaks in one or
more of the sensor values output by the pointer. For example,
pitching the pointer up may be detected by simply thresholding the
output of the accelerometer corresponding to pitch.
[0108] In this case, the system is preprogrammed with gesture
threshold definitions. Each of the definitions corresponds to a
predefined threshold applicable to a particular single sensor
output or a set of thresholds applicable to a particular group of
sensor outputs. Each definition is associated in the process to a
particular gesture, which is in turn known to the system to
represent a call for a particular control action to be applied to a
particular electronic component that is controllable by the host
computer. The thresholds are designed to indicate that the pointer
has been moved in a particular direction with an excursion from a
starting point which is sufficient to ensure the gesture associated
with the threshold or thresholds has occurred. The starting point
could be any desired, but for practical reasons, the starting point
in tested versions of the present control system was chosen to be
with the pointer pointed at the selected object. Thus, it was
necessary for the user to point the pointing at the selected
object. Pointing at an object establishes a local coordinate system
around the object, so that "up", "down", "left" and "right" are
relative to where the object appears to the user. For example, "up"
in the context of a standing user pointing at an object on the
floor means pitching up from a pitched down position, and so
on.
[0109] It would be possible for the electronic component control
system to determine when the user is pointing at the selected
object using the procedures described above in connection with
determining what the pointer is pointing at for the purpose of
selecting that object. However, a simpler method is to have the
user depress the button on the pointer whenever he or she is
pointing at the object and wants to control the associated
electronic device using a gesture. Requiring the user to depress
the button while gesturing allows the system to easily determine
when a gesture begins. In other words, the system records sensor
values only after the user depresses the button, and thus gives a
natural origin from which to detect trends in sensor values.
[0110] Recognizing gestures using a thresholding technique relies
on the gestures being simple and of a short duration. One
straightforward way of accomplishing this would be to restrict the
gestures to a single movement of the pointer in a prescribed
direction. For example, one gesture could be to rotate the pointer
upward (i.e., pitch up), while another gesture could be to rotate
the pointer downward (i.e., pitch down). Other examples of
appropriate gestures would be to pan the pointer to the right
(i.e., increase the yaw angle), or to the left (i.e., decrease the
yaw angle). The sensor output or outputs used to establish the
gesture threshold definitions and to create the input sequence to
be discussed shortly are tailored to the gesture. Thus, the
accelerometer and/or the magnetometer outputs would be an
appropriate choice for the pitch up or pitch down gesture, while
the gyroscope output would not. Similarly, the gyroscope and/or the
magnetometer outputs would be an appropriate choice for the
side-to-side gesture (i.e., changing the yaw angle), while the
accelerometer output would not. In general, when a simple one
directional gesture is employed to represent a control action, the
sensor output or outputs that would best characterize that motion
are employed to establish the threshold definitions and the input
sequence.
[0111] Given the foregoing ground rules, a procedure for gesture
recognition based on a thresholding technique will now be described
in reference to FIGS. 20A and B. The procedure begins with the user
pointing to a previously selected object in the environment that is
associated with an electronic component controllable by the host
computer and holding down the pointer's button (process action
2000). The user then performs the particular gesture associated
with the electronic component that corresponds to the desired
control action (process action 2002). Finally, once the gesture is
complete, the user releases the pointer's button (process action
2004). Meanwhile, the periodic requests directing the pointer to
provide orientation messages continue to be sent in the manner
described previously (process action 2006). The gesture recognition
process waits for an orientation message to be received (process
action 2008), and upon receipt determines whether the switch state
indicator included in the message indicates that the pointer's
button is activated (process action 2010). If not, process actions
2008 and 2010 are repeated. When, it is discovered that the button
state indicator indicates the button is activated, then in process
action 2012, prescribed pointer sensor outputs from the orientation
message are recorded. Then, a previously unselected one of the
gesture threshold definitions associated with the selected object
is selected (process action 2014). Next, any threshold of the
selected gesture threshold definition exceeded by the recorded
sensor outputs applicable to the threshold (i.e., associated with
the same sensor output) is identified (process action 2016). There
may be more than one. It is then ascertained if all the gesture
threshold definitions associated with the selected object have been
selected and processed (process action 2018). If not, process
actions 2014 through 2018 are repeated until all the definitions
have been processed. At this point, it is determined if all of the
thresholds in one of the definitions have been exceeded (process
action 2020). If so, then it is deemed that the user has performed
the gesture associated with that definition. As such, the gesture
is identified (process action 2022), and the control action
associated with that gesture is initiated by the host computer
(process action 2024). If not, then no control action is initiated.
It is noted that this latter result will only occur if the user
improperly performed the desired gesture procedure or if noise in
the system prevented accurate sensor readings from reaching the
host computer.
3.0 MULTIMODAL INTEGRATION
[0112] The complementary nature of speech and gesture is well
established. It has been shown that when naturally gesturing during
speech, people will convey different sorts of information than is
conveyed by the speech [4]. In more designed settings such as
interactive systems, it may also be easier for the user to convey
some information with either speech or gesture or a combination of
both. For example, suppose the user has selected an object as
described previously and that this object is a stereo amplifier
controlled via a network connection by the host computer. Existing
speech recognition systems would allow a user to control the volume
by, for example, saying "up volume" a number of times until the
desired volume is reached. However, while such a procedure is
possible, it is likely to be more efficient and precise for the
user to turn a volume knob on the amplifier. This is where the
previously described gesture recognition system can come into play.
Rather than having to turn a physical knob on the amplifier, the
user would employ the pointer to control the volume by, for
example, pointing at the stereo and rolling the pointer clockwise
or counterclockwise to respectively turn the volume up or down. The
latter procedure can provide the efficiency and accuracy of a
physical volume knob, while at the same time providing the
convenience of being able to control the volume remotely as in the
case of the voice recognition control scheme. This is just one
example of a situation where gesturing control is the best choice,
there are others. In addition, there are many situations where
using voice control would be the best choice. Still further, there
are situations where a combination of speech and gesture control
would be the most efficient and convenient method. Thus, a combined
system that incorporates the previously described gesturing control
system and a conventional speech control system would have distinct
advantages over either system alone.
[0113] To this end, the present invention includes the integration
of a conventional speech control system into the gesture control
and pointer systems which results in a simple framework for
combining the outputs of various modalities such as pointing to
target objects and pushing the button on the pointer, pointer
gestures, and speech, to arrive at a unified interpretation that
instructs a combined environmental control system on an appropriate
course of action. This framework decomposes the desired action
(e.g., "turn up the volume on the amplifier") into a command (i.e.,
"turn up the volume") and a referent (i.e., "the amplifier") pair.
The referent can be identified using the pointer to select an
object in the environment as described previously or using a
conventional speech recognition scheme, or both. The command may be
specified by pressing the button on the pointer, or by a pointer
gesture, or by a speech recognition event, or any combination
thereof. Interfaces that allow multiple modes of input are called
multimodal interfaces. With this multimodal command/referent
representation, it is possible to effect the same action in
multiple ways. For example, all the following pointing, speech and
gesture actions on the part of the user can be employed in the
present control system to turn on a light that is under the control
of the host computer: [0114] a) Say "turn on the desk lamp"; [0115]
b) Point at the lamp with the pointer and say "turn on"; [0116] c)
Point at the lamp with the pointer and perform a "turn on" gesture
using the pointer; [0117] d) Say "desk lamp" and perform the "turn
on" gesture with the pointer; [0118] e) Say "lamp", point toward
the desk lamp with the pointer rather than other lamps in the
environment such as a floor lamp, and perform the "turn on" gesture
with the pointer; [0119] f) Point at the lamp with the pointer and
press the pointer's button (assuming the default behavior when the
lamp is off and the button is clicked, is to turn the lamp on).
[0120] By unifying the results of pointing, gesture recognition and
speech recognition, the overall system is made more robust. For
example, a spurious speech recognition event of "volume up" while
pointing at the light is ignored, rather than resulting in the
volume of an amplifier being increased, as would happen if a speech
control scheme were being used alone. Also consider the example
given above where the user says "lamp" while pointing toward the
desk lamp with the pointer rather than other lamps in the
environment, and performing the "turn on" gesture with the pointer.
In that example just saying lamp is ambiguous, but pointing at the
desired lamp clears up the uncertainty. Thus, by including the
strong contextualization provided by the pointer, the speech
recognition may be made more robust [5].
[0121] The speech recognition system employed in the tested
versions of the present invention is Microsoft Corporation's Speech
API (SAPI), which employs a very simple command and control (CFG)
style grammar, with preset utterances for the various electronic
components and simple command phrases that apply to the components.
The user wears a wireless lapel microphone to relay voice commands
to a receiver which is connected to the host computer and which
relays the received speech commands to the speech recognition
system running on the host computer.
[0122] There is still a question as to how to take in the various
inputs from the pointer, gesture recognition and speech recognition
events, some of which may be complementary or even contradictory,
and best determine what action the user wants performed and on what
electronic component. While various computational frameworks could
be employed, the multimodal integration process employed in the
present control system uses a dynamic Bayes network [6] which
encodes the various ways that sensor outputs may be combined to
identify the intended referent and command, and initiate the proper
action.
3.1 Bayes Network
[0123] The identity of the referent, the desired command and the
appropriate action are all determined by combining the outputs of
the speech recognition system, gesture recognition system and
pointing analysis processes using a dynamic Bayes network
architecture. Bayes networks have a number of advantages that make
them appropriate to this task. First, it is easy to break apart and
treat separately dependencies that otherwise would be embedded in a
very large table over all the variables of interest. Secondly,
Bayes networks are adept at handling probabilistic (noisy) inputs.
And further, the network represents ambiguity and incomplete
information that may be used appropriately by the system. In
essence the Bayes network preserves ambiguities from one time step
to the next while waiting for enough information to become
available to make a decision as to what referent, command or action
is intended. It is even possible for the network to act proactively
when not enough information is available to make a decision. For
example, if the user doesn't point at the lamp, the system might
ask which lamp is meant after the utterance "lamp".
[0124] However, the Bayes network architecture is chosen primarily
to exploit the redundancy of the user's interaction so as to
increase confidence that the proper action is being implemented.
The user may specify commands in a variety of ways, even though the
designer specified only objects to be pointed to, utterances to
recognize and gestures to recognize (as well as how referents and
commands combine to result in action). For example, it is natural
for a person to employ deictic (pointing) gestures in conjunction
with speech to relay information where the speech is consistent
with and reinforces the meaning of the gesture. Thus, the user will
often naturally indicate the referent and command applicable to a
desired resulting action via both speech and gesturing. This
includes most frequently pointing at an object the user wants to
affect.
[0125] The Bayes network architecture also allows the state of
various devices to be incorporated to make the interpretation more
robust. For example, if the light is already on, the system may be
less disposed to interpret a gesture or utterance as a "turn on"
gesture or utterance. In terms of the network, the associated
probability distribution over the nodes representing the light and
its parents, the Action and Referent nodes, are configured so that
the only admissible action when the light is on is to turn it off,
and likewise when it is off the only action available is to turn it
on.
[0126] Still further, the "dynamic" nature of the dynamic Bayes
network can be exploited advantageously. The network is dynamic
because it has a mechanism by which it maintains a short-term
memory of certain values in its network. It is natural that the
referent will not be determined at the exact moment in time as the
command. In other words a user will not typically specify the
referent by whatever mode (e.g., pointing and/or speech) at the
same time he or she relays the desired command using one of the
various methods available (e.g., pointer button push, pointer
gesture and/or speech). If the referent is identified only to be
forgotten in the next instant of time, the association with a
command that comes after it will be lost. The dynamic Bayes network
models the likelihood of a referent or a command applying to future
time steps as a dynamic process. Specifically, this is done via a
temporal integration process in which probabilities assigned to
referents and commands in the last time step are brought forward to
the current time step and are input along with new speech, pointing
and gesture inputs to influence the probability distribution
computed for the referents and commands in the current time step.
In this way the network tends to hold a memory of a command and
referent which decays over time, and it is thus unnecessary to
specify the command and referent at exactly the same moment in
time. It is noted that in the tested implementation of the Bayes
network, this propagation occurred four times a second.
[0127] An example of a Bayes network architecture implemented for
the present electronic component control system is shown in FIG.
21. As can be seen, the command node 2100 which is essentially a
list of probabilities that a command recognizable to the system is
the command the user wants to implement, is influenced by input
from a CommandLess1 node 2102 representing the previous command
probability distribution from the last time step. In addition, the
command node 2100 is also influenced by inputs from other nodes
indicating that the pointer button is activated (ButtonClick node
2104), a particular gesture has been performed (Gesture node 2106),
an action has already been taken (ActionTaken node 2108), and a
particular speech command has been recognized (SpeechCommand node
2110). The ActionTaken node 2108 is set by the present program as a
way to force the Command node 2100 to be cleared (i.e., to have no
preference on the value of Command) once an action has been taken.
In this way the Command node 2100 will not cause an action to be
taken twice. Whereas, the referent node 2112, which is essentially
a list of probabilities that a referent controllable by the system
is the referent the user wants to affect, is influenced by input
from a ReferentLess1 node 2114 representing the previous referent
probability distribution from the last time step. In addition, the
referent node 2112 is also influenced by inputs from other nodes
indicating that the user is pointing at a particular target object
(PointingTarget node 2116) and that the user has specified a
particular referent verbally (SpeechReferent node 2118).
[0128] The Command node 2100 and the Referent node 2112 (via a
ReferentClass node 2120) in turn influence the Action node 2122, as
do various device state nodes represented by Light1 node 2124,
Light2 node 2126 and Light3 node 2128. The ReferenctClass node 2120
maps each referent to a class type (e.g., Light1 and Light2 might
both be ".times.10" type lights). This allows actions to be
specified over a set of commands and the referent class (rather
then each referent instance). Such an approach is an efficient way
of setting up the network as typically multiple referents in an
environment will work similarly. Without this node 2120, it would
be necessary to specify a command and action over each referent
even though they would likely be the same within the same class of
devices.
[0129] The device state nodes indicate the current state of a
device where that information is important to the control system.
For example, if the device state nodes represent the state of a
light (i.e., light 1), the node could indicate if the light is on
or off. It is noted that a device state node only influences the
action node 2122 when the referent node 2112 indicates that the
electronic component associated with the device state node is the
referent. Finally, a SpeechAction node 2130 can also provide an
input that influences the action node 2122 and so the action
ultimately performed by the host computer. The speech action input
is a way to completely specify the Action from a single utterance,
thereby bypassing the whole dichotomy of Command and Referent. For
example, SpeechAction node 2130 might map to a speech recognition
utterance of "turn on the light" as a single unit, rather than
saying "turn on" (Command) and "the light" (Referent). This node
2130 can also be useful when an utterance does not fit into the
Command/Referent structure, but maps to Actions anyway. For
example, the utterance "make it brighter in here" can be mapped to
an Action of turning on a light, even though no specific Command or
Referent was specified in the utterance.
[0130] Typically, the particular electronic component corresponding
to the referent, and in many cases the particular command given by
the user to affect the referent, dictate what the action is to be.
However, the aforementioned device states can also play into this
by restricting the number of possible actions if the device state
applies to the referent. For example, assume the pointer is
pointing at light 1. As a result the PointingTarget node in the
Bayes network is "set" to Light1. This causes the referent node to
also be "set" to Light1, assuming there are no other contrary
influencing inputs to the node. In addition, as the referent is set
to Light1, the state of this light will influence the Action node.
Assume the light is on. Also assume there are only two possible
actions in this case, i.e., turn the light off if it is on, or do
nothing. Thus, the possible actions are limited and so when a
command in input (e.g., the speech command to "turn off"), the
confidence level will be high that this is the correct action in
the circumstances. This added influence on the Action node causes
the probability distribution of the node to collapse to
"TurnOffLight." The system then takes the appropriate action to
turn off the light.
4.0 EXPERIMENTAL RESULTS
[0131] A prototype of the foregoing electronic component control
system was constructed and used to control a variety of devices in
a living room-like scenario. Specifically, the user was able to
control the following electronic components using the pointer and a
series of simple voice commands.
4.1 .times.10 Lighting
[0132] A user is able to turn multiple lights in the room on and
off by pointing the pointer at a light and depressing the button on
the pointer. The user then utters the phrases "turn on" or "turn
off," as desired to turn the light on or off. In addition, a
selected light may be dimmed or brightened via gesturing by
respectively rotating the pointer down or up while pointing at the
light.
4.2 A Media Player Running on a Computer
[0133] A user is also able to control a media player. Specifically,
the user points the pointer at the host computer's monitor where
the media player's GUI is displayed, and depresses the pointer's
button to start the player or to pause it. The user can also roll
the pointer to the left or right to change the volume, and can
gesture up or down to move the previous or next tracks in the play
list. "Volume up," "volume down," "next" and "previous" utterances
command the player accordingly.
4.3 Cursor Control on a Computer Monitor
[0134] A user can point at a computer display and click the
pointer's button to give control of the cursor to the pointer. The
cursor is then moved around the display's screen by pointing the
pointer around the screen [7]. The pointer's button acts as the
left mouse button. Clicking on a special icon in the corner of the
display exits the cursor control mode.
4.4 Color Kinetics Lights
[0135] A user can also point the pointer at a special computer
controlled arrays of red, green, and blue lights to brighten them
over time. When the user points away, the color gradually decays.
Rolling the pointer to the left or right changes the red, green and
blue combination sent to the light, changing the lights color.
5.0 FEEDBACK FEATURES
[0136] It is noted that for the prototype system, an audio feedback
scheme was employed where an audible sound was generated by the
host computer when the selected target changes. This audio feedback
assures the user that the desired object has been selected, and
therefore assists in the selection process. In addition, one of the
aforementioned visible spectrum LEDs on the pointer (in this case
the green one) was lit via a command from the host computer when
the pointer was pointing at an object known to the system.
[0137] It is noted that this feedback feature could be expanded
beyond that implemented in the prototype. The pointer described
previously preferably has two differently colored visible spectrum
LED with which to provide feedback to the user. For example, these
could be used to indicate to the user that an input of some kind
was not understood by the component control system. Thus, if for
instance the voice recognition system did not understand a command
or an identification of a referent, the control system could cause
one of the visible LEDs (e.g., the red one) to light up. The
visible spectrum LEDs could even be used to provide the status of a
device associated with an object that the user has selected. For
instance, one of the LEDs could be illuminated to indicate the
device was on, while the other would indicate the device was off.
Or, for example, the intensity of one of the LEDs could be varied
in proportion to volume setting on a stereo amplifier. These are
just a few examples of the types of feedback that the visible
spectrum LEDs can provide, many others are possible.
6.0 REFERENCES
[0138] [1] Jojic, N., B. Brummitt, B. Meyers, S. Harris, and T.
Huang, Estimation of Pointing Parameters in Dense Disparity Maps.
in IEEE Intl. Conf. on Automatic Face and Gesture Recognition,
(Grenbole, France, 2000). [0139] [2] Priyantha, N. B., Anit
Chakraborty, Hari Balakrishnan, The Cricket Location-Support
System. in Proceedings 6th ACM MOBICOM, (Boston, Mass., 2000).
[0140] [3] Randell, C., and Henk Muller, Low Cost Indoor
Positioning System. in Ubicomp 2001: Ubiquitous Computing,
(Atlanta, Ga., 2001), Springer-Verlag, 42-48. [0141] [4] MacNeil,
D. Hand and Mind. University of Chicago Press, 1992. [0142] [5]
Oviatt, S. L. Taming Speech Recognition Errors Within a Multimodal
Interface. Communications of the ACM, 43 (9). 45-51. [0143] [6]
Pearl, J. Probabilistic Reasoning in Intelligent Systems. Morgan
Kaufmann, San Mateo, Calif., 1988. [0144] [7] Olsen, D. R. J., T.
Nielsen, Laser Pointer Interaction. in Proceedings CHI'2001: Human
Factors in Computing Systems, (Seattle, 2001), 17-22. [0145] [8]
Rabiner, L. R., Juang B. H., An Introduction To Hidden Markov
Models. IEEE ASSP Magazine (January 86) 4-15.
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