U.S. patent application number 10/975139 was filed with the patent office on 2006-05-04 for electronic device compass operable irrespective of localized magnetic field.
This patent application is currently assigned to Texas Instruments Incorporated. Invention is credited to Stephan M. Bork.
Application Number | 20060090359 10/975139 |
Document ID | / |
Family ID | 36127546 |
Filed Date | 2006-05-04 |
United States Patent
Application |
20060090359 |
Kind Code |
A1 |
Bork; Stephan M. |
May 4, 2006 |
ELECTRONIC DEVICE COMPASS OPERABLE IRRESPECTIVE OF LOCALIZED
MAGNETIC FIELD
Abstract
An electronic device (10). The device comprises means (14) for
displaying a compass directional bearing. The device also comprises
means (18, 26, CAM) for determining the compass directional bearing
unresponsive to a local magnetic field in which the electronic
device is located, wherein the means for determining comprises
image capturing circuitry.
Inventors: |
Bork; Stephan M.; (Dallas,
TX) |
Correspondence
Address: |
TEXAS INSTRUMENTS INCORPORATED
P O BOX 655474, M/S 3999
DALLAS
TX
75265
US
|
Assignee: |
Texas Instruments
Incorporated
Dallas
TX
|
Family ID: |
36127546 |
Appl. No.: |
10/975139 |
Filed: |
October 28, 2004 |
Current U.S.
Class: |
33/361 |
Current CPC
Class: |
G01C 17/28 20130101 |
Class at
Publication: |
033/361 |
International
Class: |
G01C 17/28 20060101
G01C017/28 |
Claims
1. An electronic device, comprising: means for displaying a compass
directional bearing; and means for determining the compass
directional bearing unresponsive to a local magnetic field in which
the electronic device is located, wherein the means for determining
comprises image capturing circuitry.
2. The device of claim 1 wherein the means for determining
comprises: a computer program; and a processor operable to process
the computer program at least in part to determine the compass
directional bearing.
3. The device of claim 2 and further comprising SPS circuitry for
determining location fixes of the electronic device, wherein the
processor is operable to process the computer program to determine
the compass directional bearing in response to the location
fixes.
4. The device of claim 2, wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to images captured by the image capturing
circuitry.
5. The device of claim 4 wherein the image capturing circuitry
comprises still image capturing circuitry.
6. The device of claim 4 wherein the image capturing circuitry
comprises video image capturing circuitry.
7. The device of claim 4 wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to either extrapolation or interpolation of the
images.
8. The device of claim 2 and further comprising: SPS circuitry for
determining location fixes of the electronic device; and image
capturing circuitry; and wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to the location fixes and images captured by
the image capturing circuitry.
9. The device of claim 8 wherein the image capturing circuitry
comprises still image capturing circuitry.
10. The device of claim 8 wherein the image capturing circuitry
comprises video image capturing circuitry.
11. The device of claim 8 wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to either extrapolation or interpolation of the
images.
12. The device of claim 2 wherein the processor comprises a core
and a digital signal processor.
13. The device of claim 2 wherein the means for displaying and
means for determining are part of an electronic device selected
from a set consisting of a telephone and a personal digital
assistant.
14. The device of claim 1 wherein the means for displaying and
means for determining are part of an electronic device selected
from a set consisting of a telephone and a personal digital
assistant.
15. The device of claim 1 wherein the means for displaying
comprises means for displaying the compass directional bearing on a
depiction of a map.
16. The device of claim 1 wherein the image capturing circuitry
comprises still image capturing circuitry.
17. The device of claim 1 wherein the image capturing circuitry
comprises video image capturing circuitry.
18. An electronic device, comprising: a computer program; and a
processor operable to process the computer program at least in part
to determine a compass directional bearing at least in part in
response to image data and unresponsive to a local magnetic field
in which the electronic device is located.
19. The device of claim 18 and further comprising SPS circuitry for
determining location fixes of the electronic device, wherein the
processor is operable to process the computer program to determine
the compass directional bearing in response to the location
fixes.
20. The device of claim 18 and further comprising image capturing
circuitry for providing the image data, wherein the processor is
operable to process the computer program to determine the compass
directional bearing in response to images captured by the image
capturing circuitry.
21. The device of claim 18 wherein the image capturing circuitry is
selected from a set consisting of still image capturing circuitry
and video image capturing circuitry.
22. The device of claim 21 wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to either extrapolation or interpolation of the
images.
23. The device of claim 18 and further comprising: SPS circuitry
for determining location fixes of the electronic device; and image
capturing circuitry; and wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to the location fixes and images captured by
the image capturing circuitry.
24. The device of claim 23 wherein the image capturing circuitry is
selected from a set consisting of still image capturing circuitry
and video image capturing circuitry.
25. The device of claim 23 wherein the processor is operable to
process the computer program to determine the compass directional
bearing in response to either extrapolation or interpolation of the
images.
26. The device of claim 18 wherein the processor comprises a core
and a digital signal processor.
27. The device of claim 18 wherein the means for displaying and
means for determining are part of an electronic device selected
from a set consisting of a telephone and a personal digital
assistant.
28. The device of claim 18 wherein the image capturing circuitry is
selected from a set consisting of still image capturing circuitry
and video image capturing circuitry.
29. Computer programming for use in an electronic device comprising
a processor, the programming for causing the steps of: determining
a compass directional bearing at least in part in response to image
data and unresponsive to a local magnetic field in which the
electronic device is located; and displaying the compass
directional bearing.
30. The computer programming of claim 29, wherein the electronic
device further comprises SPS circuitry for determining location
fixes of the electronic device, wherein the determining step
determines the compass directional bearing in response to the
location fixes.
31. The computer programming of claim 29, wherein the electronic
device further comprises image capturing circuitry, wherein the
determining step determines the compass directional bearing in
response to the image data as captured by the image capturing
circuitry.
32. The computer programming of claim 31 wherein the image
capturing circuitry comprises still image capturing circuitry.
33. The computer programming of claim 31 wherein the image
capturing circuitry comprises video image capturing circuitry.
34. The computer programming of claim 29, wherein the electronic
device further comprises SPS circuitry for determining location
fixes of the electronic device and image capturing circuitry,
wherein the determining step determines the compass directional
bearing in response to the location fixes and images captured by
the image capturing circuitry.
35. The computer programming of claim 34 wherein the image
capturing circuitry is selected from a set consisting of still
image capturing circuitry and video image capturing circuitry.
36. The computer programming of claim 29 wherein the displaying
step displays the compass directional bearing on a depiction of a
map.
Description
CROSS-REFERENCES TO RELATED APPLICATION
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] The present embodiments relate to electronic devices and are
more particularly directed to a compass for use in an electronic
device, where the compass is operable irrespective of the magnetic
field in which the device is located.
[0004] Electronic devices are extremely prevalent and beneficial in
today's society and are constantly being improved due to consumer
and user demand. One technological example has been the portable or
cellular telephone marketplace, which has seen great advances in
the last many years. These devices have evolved beyond provision of
voice services alone and are now accommodating greater amounts of
data and are providing various additional features, more advanced
operating systems, and additional programming. For example,
so-called "smart phones" are envisioned as having a large impact on
upcoming generations of cellular phones. Also, various personal
digital assistants ("PDAs") are still succeeding in the marketplace
and may do so for the foreseeable future. Further, the
functionality of cellular phones and PDAs are now beginning to
overlap with the possibility of a greater combination of the
functionality of these devices into a single unit in the
future.
[0005] With the advancement of the devices introduced above,
various newer features are now being developed and implemented, as
are known in the art. One feature that is now found in some
cellular phones is a magnetically-responsive compass. As a compass,
the device serves in the ordinary sense of such a component, that
is, to present to the phone user an indication of the
directionality of the physical orientation of the phone. In the
present art, such a compass is constructed in part using an element
(or elements) that is sensitive to the local magnetic field, that
is, the field at the location of the phone. For example, one
implementation uses a two-dimensional magneto-resistive measurement
bridge, which changes its resistance in response to a change in the
orientation of the bridge as influenced by the local magnetic
field. Circuitry, such as a differential amplifier and an
analog-to-digital converter, sense the voltage output of the bridge
and translate that output into a corresponding directionality
indication.
[0006] While the preceding approach to a cellular phone compass may
prove a desirable feature in some instances, the present inventor
has observed that it has certain drawbacks. For example, the
magneto-resistive measurement bridge extends only in two
dimensions, presumably to coincide with the two-dimensional nature
of the circuit board(s) inside the phone. As such, the bridge might
produce erroneous and indeed erratic indications if the phone is
positioned in a manner that is not parallel to the earth's surface.
As another example, because the bridge is responsive to local
magnetic field, then the resulting output will produce an erroneous
indication of direction when the phone is in a location that is
subject to aberrations in the earth's magnetic filed or nearby
metal objects that might distort the earth's magnetic field at the
then-existing location of the phone. As still another example, both
device cost and circuit board space are increased with the
inclusion of the bridge circuit and its associated circuitry.
[0007] As a result of the preceding, there arises a need to address
the drawbacks of the prior art as is achieved by the preferred
embodiments described below.
BRIEF SUMMARY OF THE INVENTION
[0008] In one preferred embodiment, there is an electronic device.
The device comprises means for displaying a compass directional
bearing. The device also comprises means for determining the
compass directional bearing unresponsive to a local magnetic field
in which the electronic device is located, wherein the means for
determining comprises image capturing circuitry.
[0009] Other aspects are also disclosed and claimed.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0010] FIG. 1a illustrates a front view of an example of a wireless
telephone handset 10 into which a preferred embodiment is
implemented.
[0011] FIG. 1b illustrates a rear view of the wireless telephone
handset 10 of FIG. 1a.
[0012] FIG. 2 illustrates an electrical block diagram of various
functional features of handset 10.
[0013] FIG. 3 illustrates a flowchart of a method 100 of operation
of handset 10 in connection with providing a compass functionality
in the inventive scope.
[0014] FIG. 4a illustrates an example of directional movement of
handset 10 between two location fixes.
[0015] FIG. 4b illustrates the example of FIG. 4a after handset 10
rotates 90 degrees clockwise following its second location fix in
FIG. 4a.
[0016] FIG. 4c illustrates the 90 degree clockwise rotation of
handset 10 as occurring at the second location fix and from FIG. 4a
to FIG. 4b.
[0017] FIG. 5 illustrates an example of directional movement of
handset 10 along a curve with numerous location fixes.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The present invention is described below in connection with
a preferred embodiment, namely as implemented into an electronic
device that includes a compass that operates in response to various
features in that electronic device. Thus, such a compass may be
included in a cellular telephone or a personal digital assistant
("PDA"), by ways of example. Still other electronic devices may
implement such aspects as well, as may be evident to one skilled in
the art. Accordingly, it is to be understood that the following
description is provided by way of example only and is not intended
to limit the inventive scope.
[0019] FIG. 1a illustrates a front view of an example of a wireless
telephone handset 10 into which the preferred embodiments are
implemented. Handset 10 includes an antenna ANT for bi-directional
communications in the sense of a cellular or wireless device.
However, only received signals are necessary for purposes of a
compass function that is associated with the preferred embodiments
and, thus, the preferred embodiments also may be implemented in
connection with a device that is only operable to receive certain
signals, described later, rather than to bi-directionally
communicate signals such as in the case of a cellular telephone. In
the example of FIG. 1a (and 1b), handset 10 provides the
conventional human interface features, including a microphone MIC,
a speaker SPK, a visual display 12, and a keypad 14. Keypad 14
includes the usual keys for a wireless telephone handset, including
numeric keys 0 through 9, the * and # keys, and other keys as in
conventional wireless telephone handsets. In addition and for
reasons more clear below, keypad 14 is shown to include a dedicated
COMPASS key 16. According to the preferred embodiments of the
invention, COMPASS key 16 may be pressed to invoke a compass
feature whereby in response to that action and further processing
described later, display 12 provides a visual indication of the
directional heading of handset 10.
[0020] FIG. 1b illustrates a rear view of wireless telephone
handset 10 from FIG. 1a. This rear perspective is shown to
illustrate that handset 10 in the preferred embodiments also
includes a camera CAM. As with many popular contemporary cellular
phones, camera CAM is on the rear of handset 10, although such a
location is not necessary. Further, the illustration of camera CAM
in FIG. 1b is more particularly of its lens for sake of taking
pictures (still or video), as further described later, and one
skilled in the art should appreciate that within handset 10
additional circuitry in this regard is coupled to that lens as
further described below.
[0021] Referring now to FIG. 2, the construction of an exemplary
electrical block diagram architecture for handset 10 according to a
preferred embodiment is now described. Of course, the particular
architecture of a wireless handset (or other device within the
inventive scope) may vary from that illustrated in FIG. 2, and as
such the architecture of FIG. 2 is presented only by way of
example.
[0022] As shown in FIG. 2, the functionality of handset 10 is
generally controlled by a processor 18. Processor 18 may take
various forms, including an implementation where it is embodied as
a single integrated circuit that includes both a core and a digital
signal processor ("DSP"). High-performance processors that are
suitable for use as such a core include the advanced RISC ("reduced
instruction set computer") machine ("ARM") designed by a company
known as ARM Limited. Further, examples of DSPs suitable for such
use include the TMS320c5x family of digital signal processors
available from Texas Instruments Incorporated. In any event, the
functionality of processor 18 preferably includes programmable
logic, such as a microprocessor or microcontroller, that controls
the operation of handset 10 according to a computer program or
sequence of executable operations stored in program memory.
Preferably, the program memory is on-chip with processor 18, but
alternatively it may be implemented in read-only memory ("ROM") or
other storage in a separate integrated circuit. The computational
capability of processor 18 depends on the level of functionality
required of handset 10, including the "generation" of wireless
services for which handset 10 is to be capable. As known in the
art, modern wireless telephone handsets can have a great deal of
functionality, including the capability of Internet web browsing,
email handling, digital still and video photography, global
positioning system ("GPS") features, game playing, PDA
functionality, and the like, as well as the additional compass
functionality detailed later. The DSP functionality of processor 18
performs the bulk of the digital signal processing for signals to
be transmitted and signals received by handset 10. These functions
include the necessary digital filtering, coding and decoding,
digital modulation, and the like. Lastly, note that DSPs that are
comparable in various respects are available in combined form with
the above-discussed core on a single integrated circuit as a
combined processor referred to by Texas Instruments Incorporated as
an OMAP, although in present form they do not include the compass
functions detailed later.
[0023] Continuing the example of FIG. 2, processor 18 is coupled to
visual display 12 and keypad 14, each for performing well-known
functionality. In addition, and by way of introduction to aspects
detailed later, a user may press COMPASS key 16 (see FIG. 1a) which
is part of keypad 14, and that action invokes a control signal to
processor 18 so that it may process various signals so as to
provide a compass directional indicator on display 12. Continuing
with other functions of FIG. 2. Processor 18 also is coupled to a
power management function 20. Power management function 20
distributes regulated power supply voltages to various circuitry
within handset 10 and manages functions related to charging and
maintenance of the battery (not shown) of handset 10, including
standby and power-down modes to conserve battery power. Handset 10
also includes radio frequency ("RF") circuitry 22, which is coupled
to antenna ANT and to an analog baseband circuitry 24. RF circuitry
22 consumes power under control of power management function 20,
and it includes such functions as necessary to transmit and receive
the RF signals at the specified frequencies to and from the
wireless telephone communications network that communicates with
handset 10. Thus, RF circuitry 22 is contemplated to include such
functions as modulation circuitry and RF input and output drivers.
By applying the necessary filtering, coding and decoding, and the
like, analog baseband circuitry 24 processes the signals to be
transmitted (as received from microphone MIC) prior to modulation
and the received signals (to be output over speaker SPK) after
demodulation (hence in the baseband). Lastly, typical functions
included within analog baseband circuitry 24 include an RF
coder/decoder ("CODEC"), a voice CODEC, speaker amplifiers, and the
like, as known in the art.
[0024] Handset 10 also includes a GPS module 26, which also
consumes power under control of power management function 20 and is
coupled to receive signals from RF circuitry 22 and to function
generally according to the art to process those signals in
connection with processor 18. Note that GPS is only used here by
way of example, when in fact GPS is one example of a broader
category of the satellite positioning system ("SPS"). Prior to its
use in cellular phones, SPS has existed for decades and has been
used in military and civil applications. The current SPS system
includes the well-known US-owned global positioning satellite
("GPS") system or NAVSTAR and the Russia-owned Global Navigation
Satellite System ("GLONASS"). Additionally, the European Union has
started its effort to support SPS with an initiative to position a
constellation of satellites, called the Galileo system, for
completion in the future. In any event, many cellular phones are
now including an SPS functionality, and for purposes of the
preferred embodiments this functionality is shown by way of example
as GPS, while it should be understood that the preferred
embodiments may be implemented in connection with any SPS
technique. In any event, and as detailed later, the GPS information
provided in this manner also may be used in connection with a novel
compass functionality. Looking presently to the GPS function in
general, note that GPS features are now included in various
cellular telephones to process GPS signals from a receiver, such as
from the combination of antenna ANT and RF circuitry 22 or,
alternatively, GPS module 26 may include its own RF circuitry, in
which case module 26 may receive signals directly from antenna ANT,
with such an alternative connection also being shown in FIG. 2. In
either event, module 26 receives unidirectional communications from
the satellite GPS system which, as known in the GPS art, is a
constellation of a number of satellites that orbit the earth at a
given angle relative to the equator. Each satellite transmits coded
position and timing information in a low power signal and, in
response, that information may be received by any GPS-enabled
device, including handset 10. In the case of the latter, those
signals are received by antenna ANT, converted by RF circuitry 22
and processed by GPS module 26, either alone or in combination with
the capabilities of processor 18. Thus, one or the combination of
these functional blocks preferably has a measurement engine and
position engine from which a determination of a so-called location
fix of handset 10 is determined, that is, the geographic coordinate
position of handset 10. The accuracy of the location fix depends on
various considerations, but even in a consumer-level device that
accuracy may be on the order of one to two meters. Further, GPS
location fix determinations may be improved in accuracy with
supplementation from other GPS services, as known in the art. In
any event, with the GPS location fix of the cellular phone, the
phone may use that information for various applications. In one
example, a contemporary standard requires that a phone such as
handset 10 be operable to report its location in the event that its
user calls the emergency 9-1-1 service and, thus, the GPS
functionality of the phone supports this requirement. In another
example, the GPS information may be used in connection with a
mapping program associated with the phone (or other electronic
device), so as to depict on display 12 the location of the phone
(and its user) on a displayed map. As detailed below, however, this
information is also used in part to support a novel compass
functionality, that is, to provide a directional heading indication
of handset 10.
[0025] FIG. 3 illustrates a flowchart of a method 100 of operation
of handset 10 in connection with providing a compass functionality
in the inventive scope. By way of introduction, note that the use
of a flowchart is merely to explain various functional concepts and
steps, where the order of these steps may be adjusted and where
they may be represented in an alternative fashion, such as in a
state diagram. Moreover, the steps of FIG. 3 are only directed to
certain aspects pertaining to the management of the compass
functionality, while one skilled in the art will readily appreciate
that various other functions may occur with respect to handset 10,
either simultaneously or in addition to those set forth in FIG. 3.
Note also that the compass functionality of method 100 may be
achieved by including additional computer programming software in
connection with processor 18 (e.g., in local or remote memory or
other computer-readable medium), where that software operates with
respect to data provided by already-existing hardware including GPS
module 26 and camera CAM, but without reference to any
magnetic-sensitive device as in the prior art. These aspects will
be appreciated below, as will be manners of implementing such
software by one skilled in the art.
[0026] Turning to method 100 of FIG. 3, it commences with a step
110, where the compass feature is enabled. In a preferred
embodiment, the user of handset 10 may accomplish this task by
pressing COMPASS key 16 (FIG. 1a). In an alternative embodiment,
the compass selection may be programmed into another general
purpose or programmable key or otherwise invoked by operating
handset 10 in some desired manner, including navigating to a menu,
interface, or the like on display 12. In any event, once the
feature is enabled, method 100 continues from step 110 to step
120.
[0027] In step 120, GPS module 26 determines a first location fix
LF.sub.x, that is, from signals received from RF circuitry 22 and
with known GPS functionality, a first set of GPS geographic
coordinates are determined for handset 10. Note that such
functionality may be selected from various alternatives and,
moreover, the rate at which first location fix LF.sub.x is
determinable may depend on the supporting GPS methodology. For
example, so-called assisted GPS now exists and may be incorporated
into handset 10 so as to reduce the time needed to determine a
first location fix. To further demonstrate step 120 and later
steps, FIGS. 4a through 4c provide simplified top views of the
positioning of handset 10 in different locations. Moreover, handset
10 is shown in those Figures in general form, with an outline of
the handset and with camera CAM on its underside (as shown in FIGS.
4a through 4c with a dashed outline), facing generally downward
toward the ground. Further in this regard and as appreciated with
the remaining discussion, in the preferred embodiments a user of
handset 10 is generally encouraged to position handset 10 in this
manner while performing method 100, that is, in a horizontal
manner, parallel to the ground and with camera CAM facing downward.
As also appreciated later, however, modest deviations in the
horizontal positioning of handset 10 will not interfere with its
compass functionality. In any event, FIG. 4a illustrates handset 10
wherein the user (not shown) is pointing handset 10 with a bearing
of east, and location fix LF.sub.x is determined from step 110 at
that location. Thereafter, method 100 continues from step 120 to
step 130.
[0028] In step 130, processor 18 enables camera CAM to begin to
capture successive images in time. In a preferred embodiment, these
successive images are captured as an ongoing video stream
commencing with step 130. However, in an alternative embodiment,
successive still images may be captured. Either approach may be
achieved using many of various known or developed image techniques,
such as through mpeg, jpeg, or other technologies as ascertainable
by one skilled in the art. Looking again to FIG. 4a, therefore,
image capture occurs at location fix LF.sub.x and continues as
handset 10 is moved eastward. While image capture continues, method
100 continues from step 130 to step 140.
[0029] In step 140, GPS module 26 determines a second location fix
LF.sub.x+1, where the subscript is intended to denote that it
follows the first location fix, LF.sub.x, determined in step 120.
Again, the same GPS functionality used to achieve step 120 is
preferably used to achieve step 140. Thus, in FIG. 4a, step 140
occurs as shown to the right of the Figure, which depicts handset
10 at second location fix LF.sub.x+1. Next, method 100 continues
from step 140 to step 150.
[0030] In step 150, processor 18 determines the directional bearing
(i.e., direction of movement) of handset 10 based on the difference
of second location fix LF.sub.x+1 and first location fix LF.sub.x.
In other words, these two points necessarily define a line and,
thus, with a geographical coordinate for each, the directional
bearing along that line may be determined. In the example of FIG.
4a, therefore, this direction is determined to be east, that is,
handset 10 has been shown in that Figure to have been moved east,
as will be confirmed by calculating the directional difference
between LF.sub.x+1 and LF.sub.x. Note also in this regard that
calculating direction based on different GPS fixes is known in the
automotive art, where systems are now available that perform this
function, although they do so with expectations about the fixed
orientation of the receiver relative to the remainder of the
vehicle (and the ground) as well as an anticipation of the vehicle
traveling at speeds greater than that which would be expected from
a human traveling without vehicle assistance and carrying a
portable device such as handset 10. In any event, after step 150,
method 100 continues from step 150 to step 160.
[0031] Step 160 is illustrated in connection with FIG. 4b. Turning
first then to FIG. 4b, it is intended to demonstrate the two
location fixes of FIG. 4a, but now it is shown that the user of
handset 10 has rotated handset 10 by an amount of 90 degrees
clockwise, where such movement is also shown by way of
demonstration in FIG. 4c. Particularly, FIG. 4c illustrates handset
10 in a position 10.sub.4a, which is intended to illustrate the
orientation of handset 10 at the end of its eastward movement in
FIG. 4a, followed by a 90 degree clockwise rotation to a position
10.sub.4b, which is intended to illustrate the orientation of
handset 10 after both its eastward movement in FIG. 4a and its 90
degree clockwise rotation shown in FIG. 4b. Thus, returning to FIG.
4b, it may be appreciated that while handset 10 previously moved
east as was determined by step 150, the directional bearing of
handset 10 is now south, given the 90 degree clockwise rotation.
Returning then to FIG. 3 and step 160, it determines a difference
in bearing, if any, from any angular change in images that have
been or are being captured by camera CAM. In other words, assuming
an image IM.sub.T captured at a time T, then step 160 evaluates
that image based on a range R of other images, which may be before
and/or after image IM.sub.T is captured; hence, step 160 is shown
to make its determination relative to images IM.sub.T.+-.IM.sub.R.
For example, assume that a number N of images are captured between
the time handset 10 is positioned as shown at location fix
LF.sub.x+1 in FIG. 4a and as shown at location LF.sub.x+1 in FIG.
4b, that is, assume N images are captured through the range of the
90 degree rotation of handset 10. In this or other cases, then in
step 160, various image processing techniques, including by ways of
example extrapolation and interpolation techniques used in mpeg (or
the like) video processing, are employed to determine from those N
images the direction and extent of the angular rotation of handset
10, thereby providing a corresponding determination of the change
in directional bearing of handset 10. Indeed, note that this image
processing also may account for modest variations in the horizontal
orientation of handset 10, that is, if the user while carrying
handset 10 departs from the intended preference of holding it in a
horizontal manner, then sufficient image capture and processing may
well be able to account for such deviations, while still providing
a determination of the change, if any, in directional orientation
of handset 10. Next, method 100 continues from step 160 to step
170.
[0032] In step 170, processor 18 modifies the directional bearing
from step 150 with the difference in bearing, if any, based on the
captured images. The result is provided to user 10, such as through
display 12 or through some other means of depicting direction to
that user. Thus, returning once more to FIG. 4a, step 150 will have
determined a directional bearing of east. However, the subsequent
step 160 will have determined a 90 degree clockwise rotation of
handset 10, which is used in step 170 to modify the step 150
directional bearing, thereby changing it from an east bearing to a
south bearing. The result of south, therefore, is presented to the
user of handset 10 via display 12. The presentation may take
various forms. In one embodiment, the presentation may be an
indication of directional bearing by a letter or arrow or depicted
on a screen displayed compass or directional arrow. In another
embodiment, the presentation may locate a directional indicator on
a map that shown the geographic location in which handset 10 is
located.
[0033] The preceding illustrates that method 100, as shown in the
example of FIGS. 4a through 4c, permits handset 10 to determine a
directional bearing in response to location fixes and successive
image data, all provided by circuitry and software within handset
10. Note various additional benefits of these preferred
embodiments. First, the example of FIGS. 4a through 4c is only one
of many instances in which method 100 may operate. Indeed, note
that the timing between successive location fixes and the image
capture may be shortened or lengthened so as to adjust accuracy as
well as directional bearing updates. For example, FIG. 5
illustrates another example of directional movement of handset 10,
handset 10 is shown traversing along a curve that in different
instances corresponds to various different directional bearings. In
that example, a total of seven location fixes are taken. Thus, as
between each successive location fix, a straight line might
indicate the previous general direction of movement of handset 10,
but because of the curvature of the route the then-existing actual
bearing (or orientation) of handset 10 may differ to due its
rotation of the actual physical device as it travels along the
curve. However, with sufficient image capture this additional
rotation may be ascertained as explained above in connection with
step 160 and the directional bearing may be modified in the
corresponding step 170. Thus, many other instances and examples
should be appreciated by one skilled in the art, as should the
notion that method 100 may be continuously repeated, with or
without requiring a repetition of user-input such as through step
110, whereby handset 10 continuously updates its directional
bearing by using successive or incremental location fixes as well
as captured image data.
[0034] From the above, it may be appreciated that the preferred
embodiments provide a compass for use in an electronic device.
Because the compass of the preferred embodiments determines
directional bearing based on GPS and image data, it is operable
irrespective of the magnetic field in which handset 10 is located.
In other words, the compass functionality is unresponsive to the
magnetic field that is influencing the location of handset 10. For
this reason, the preferred embodiments provide various benefits as
compared to the prior art. As one example of a benefit, additional
magnetic-responsive devices, which may add cost, complexity, size,
and weight to a portable device are not required in handset 10. As
another example of a benefit, the preferred embodiments provide a
compass functionality that is not susceptible to magnetic field
variations that would adversely affect a typical
magnetic-responsive compass. For example, there may be local
magnetic attractions if handset 10 is in the vicinity of something
made of iron or a comparably field influencing substance or device.
As another example, there may be localized aberrations in the
earth's magnetic field, and still further there is the possible
influence on magnetic-responsive devices of the different North
Poles, that is, True North and Magnetic North. Nonetheless, the
preferred embodiments as shown above are unresponsive to these
localized magnetic effects and, therefore, can prove meaningful
compass functionality in such locations without a disturbance in
the accuracy of the compass. As yet another benefit, many
contemporary cellular telephones already include both GPS and
camera functionality and, thus, in these devices, the preferred
embodiments may be implemented by adding purely software into these
devices to program them to operate as described above. Thus, the
preferred embodiments include various aspects and advantages as
compared to the prior art, and still others will be appreciated by
one skilled in the art. Moreover, while the preferred embodiments
have been shown by way of example, certain other alternatives have
been provided and still others are contemplated. Thus, the
preceding discussion and these examples should further demonstrate
that while the present embodiments have been described in detail,
various substitutions, modifications or alterations could be made
to the descriptions set forth above without departing from the
inventive scope which is defined by the following claims.
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