U.S. patent application number 09/170871 was filed with the patent office on 2001-11-15 for remote control system.
Invention is credited to IWAMURA, RYUICHI.
Application Number | 20010042245 09/170871 |
Document ID | / |
Family ID | 22621622 |
Filed Date | 2001-11-15 |
United States Patent
Application |
20010042245 |
Kind Code |
A1 |
IWAMURA, RYUICHI |
November 15, 2001 |
REMOTE CONTROL SYSTEM
Abstract
An electronic appliance remote controller which includes a
display screen (which may be part of the appliance, e.g. a TV
screen) for displaying icons representing possible operations of
the electronic appliance, and a motion detector circuit for
detecting a motion within a field of view of the motion detector
circuit. The motion detector circuit detects a predetermined motion
of a moving object within the field of view as an indication that a
remote control operation is to be started and, thereafter, tracks
the movement of the object. The motion detector circuit outputs a
cursor control signal representative of the motion of the object. A
control circuit, connected to the display screen, the electronic
appliance, and the motion detector circuit and supplied with the
cursor control signal, controls the display screen to display a
movable visual indicator, e.g. a cursor, whose own motion tracks
the movement of the moving object and the electronic appliance to
perform operations corresponding to the icons selected by the user
using the visual indicator.
Inventors: |
IWAMURA, RYUICHI; (SAN
DIEGO, CA) |
Correspondence
Address: |
PHILIP M SHAW JR
CROSBY HEAFEY ROACH & MAY
PO BOX 7936
SAN FRANCISCO
CA
941207936
|
Family ID: |
22621622 |
Appl. No.: |
09/170871 |
Filed: |
October 13, 1998 |
Current U.S.
Class: |
725/1 ;
348/E5.103 |
Current CPC
Class: |
G08C 2201/32 20130101;
G06F 3/005 20130101; G06F 3/017 20130101; H04N 21/47 20130101; G06F
3/0304 20130101; G08C 23/00 20130101 |
Class at
Publication: |
725/1 |
International
Class: |
H04N 007/16 |
Claims
What is claimed is:
1. A remote controller for an electronic appliance, comprising: a
display screen for displaying icons representing possible
operations of the electronic appliance; a motion detector for
detecting a motion within a field of view of the motion detector,
the motion detector detecting a first predetermined motion of a
moving object within the field of view as an indication that a
remote control operation is to be started and, thereafter, tracking
the movement of the object and outputting a cursor control signal
representative of the motion of the object; a control circuit,
connected to the display screen, the electronic appliance, and the
motion detector and supplied with the cursor control signal, for
controlling the display screen to display a movable visual
indicator which tracks the movement of the moving object and for
controlling the electronic appliance to perform operations
corresponding to the icons selected by the user using the visual
indicator.
2. A remote controller according to claim 1, wherein the motion
detector detects the selection of an icon by the user by detecting
a second predetermined motion pattern of the object when the visual
indicator is coincident on the display screen with a particular
icon.
3. A remote controller according to claim 2, wherein the second
predetermined motion pattern is a cessation of movement of the
object for a predetermined period of time after the visual
indicator is coincident on the display screen with the particular
icon.
4. A remote controller according to claim 1, wherein the motion
detector includes a video camera.
5. A remote controller according to claim 1, wherein the visual
indicator is a cursor.
6. A remote controller according to claim 1, wherein the electronic
appliance is a television set.
7. A remote controller according to claim 1, wherein the display
screen is a cathode ray tube.
8. A remote controller according to claim 1, wherein the moving
object is a user's hand and the first predetermined motion is a
circular hand movement.
9. A remote controller according to claim 1, wherein the motion
detector includes a video camera and calculates a motion vector of
each macro block between two adjacent video frames in a video
output signal from the video camera.
10. A remote controller according to claim 9, wherein each video
frame includes a plurality of blocks each containing vectors
representative of detected motion of the object, wherein neighbor
vectors with almost the same direction are grouped as one
region.
11. A remote controller according to claim 10, wherein for each
frame, the motion detector, in determining whether to track an
object, checks each region to determine if that region satisfies
the conditions (a) that the vector made one rotation clockwise or
counterclockwise and (b) the region returned to the start position
where it used to be and locks onto that region if conditions (a)
and (b) are both satisfied.
12. A remote controller according to claim 1, wherein the motion
detector includes a series connection of a video camera, a discrete
cosine transform (DCT) circuit for discrete cosine transform
processing a video signal output by the camera, a quantizing
circuit for quantizing the DCT processed video signal, an
invert-DCT circuit for invert DCT processing the DCT processed
video signal, a frame memory supplied with the output of the invert
DCT circuit, a subtraction node interposed between the camera and
the DCT circuit for subtracting, in the case of a predictive frame,
the camera's video signal from reconstructed intra frame data
output from the frame memory, and a summing node interposed between
the frame memory and the invert DCT processing, for adding, in the
case of a predictive frame, reconstructed intra frame data output
from the frame memory to the output signal from the invert DCT
circuit, and a motion detection circuit connected to the frame
memory which compares a past frame in the frame memory with a
current frame in the frame memory and calculates a motion vector of
each macro block between the past and current video frames.
13. A remote controller according to claim 12, wherein each video
frame includes a plurality of blocks each containing vectors
representative of detected motion of the object, wherein neighbor
vectors with almost the same direction are grouped as one
region.
14. A remote controller according to claim 13, wherein for each
frame, the motion detector, in determining whether to track an
object, checks each region to determine if that region satisfies
the conditions (a) that the vector made one rotation clockwise or
counterclockwise and (b) the region returned to the start position
where it used to be and locks onto that region if conditions (a)
and (b) are both satisfied.
15. A remote controller according to claim 1, further comprising an
automatic cursor sensitivity control means for automatically
adjusting a length of movement of the visual indicator on the
display screen relative to a corresponding length of movement of
the moving object detected by the motion detector.
16. A remote controller according to claim 15, wherein the
automatic cursor sensitivity control means adjusts the length of
movement of the visual indicator on the display screen to move a
fixed, predetermined distance on the display screen in response to
the length of the detected first predetermined motion.
17. A remote controlling method for an electronic appliance,
comprising the steps of: visually displaying on a display screen
icons representing possible operations of the electronic appliance;
detecting a motion within a field of view, including detecting a
predetermined motion of a moving object within the field of view as
an indication that a remote control operation is to be started and,
thereafter, tracking the movement of the object an outputting a
cursor control signal representative of the motion of the object;
as a function of the control signal, controlling the display screen
to display a movable visual indicator which tracks the movement of
the moving object and the electronic appliance to perform
operations corresponding to the icons selected by the user using
the visual indicator.
18. A remote controlling method according to claim 17, wherein the
step of detecting the selection of an icon by the user includes
detecting a predetermined motion pattern of the object when the
visual indicator is coincident on the display screen with a
particular icon.
19. A remote controlling method according to claim 17, wherein the
step of detecting the selection of an icon by the user includes
detecting a cessation of movement of the object for a predetermined
period of time after the visual indicator is coincident on the
display screen with a particular icon.
20. A remote controlling method according to claim 17, wherein the
visual indicator is a cursor.
21. A remote controlling method according to claim 17, wherein the
electronic appliance is a television set.
22. A remote controlling method according to claim 17, wherein the
step of displaying includes displaying on a cathode ray tube.
23. A remote controlling method according to claim 17, wherein the
predetermined motion is a circular hand movement.
24. A remote controlling method according to claim 17, wherein the
motion detecting step uses a video camera.
25. A remote controlling method according to claim 24, wherein the
motion detecting step includes calculating a motion vector of each
macro block between two adjacent video frames in a video output
signal from the video camera.
26. A remote controlling method according to claim 25, wherein each
video frame includes a plurality of blocks each containing vectors
representative of detected motion of the object, wherein neighbor
vectors with almost the same direction are grouped as one
region.
27. A remote controlling method according to claim 26, further
comprising the steps, for each frame, of determining whether to
track an object by checking each region to determine if that region
satisfies the conditions (a) that the vector made one rotation
clockwise or counterclockwise and (b) the region returned to the
start position where it used to be and locking onto that region if
conditions (a) and (b) are both satisfied.
28. A remote controlling method according to claim 24, wherein the
motion detecting step takes place as part of a process of encoding
the video output signal from the video camera according to the
motion picture experts group (MPEG) standard and includes
calculating a motion vector of each macro block between a past
video frame and a current video frame in video output signal from
the video camera.
29. A remote controlling method according to claim 28, wherein each
video frame includes a plurality of blocks each containing vectors
representative of a detected motion of the object, wherein neighbor
vectors with almost the same direction are grouped as one
region.
30. A remote controlling method according to claim 27, further
comprising the steps, for each frame, of determining whether to
track an object by checking each region to determine if that region
satisfies the conditions (a) that the vector made one rotation
clockwise or counterclockwise and (b) the region returned to the
start position where it used to be and locking onto that region if
conditions (a) and (b) are both satisfied.
31. A remote controlling method according to claim 17, further
comprising the step of automatically adjusting a length of movement
of the visual indicator on the display screen relative to a
corresponding length of the detected movement of the moving
object.
32. A remote controlling method according to claim 31, wherein
during the step of automatically adjusting the length of movement
of the visual indicator on the display screen includes moving the
visual indicator a fixed, predetermined distance on the display
screen in response to the length of the detected first
predetermined motion.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a remote control commander for an
electronic appliance, such as a television set, and more
particularly to an optical motion sensing remote control system for
an electronic appliance.
[0003] 2. Related Art
[0004] An IR (Infra Red) remote commander is a common means to
control a TV from a distance. However, existing remote commanders
have some drawbacks. They are easy to lose. The user often mistakes
a VCR commander for the TV commander. In fact, a lot of people have
a great "remote commander collection". Also one has to learn which
button is where on the commander. Remote commanders require
batteries which have to be replaced periodically. If a TV could
have a camera vision and read the user's gestures, no remote
commander would be necessary. However, it is not easy for a TV to
distinguish gestures from other moves in its camera view. One would
not want the channel to change each time the user got up to fetch a
snack from the kitchen, for example.
SUMMARY OF THE INVENTION
[0005] The above and other problems of prior art electronic
appliance remote controllers are overcome by an electronic
appliance remote controller according to the present invention
which includes a display screen (which may be part of the
appliance, e.g. a TV screen) for displaying icons representing
possible operations of the electronic appliance, and a motion
detector circuit for detecting a motion within a field of view of
the motion detector circuit. The motion detector circuit detects a
predetermined motion of a moving object within the field of view as
an indication that a remote control operation is to be started and,
thereafter, tracks the movement of the object. The motion detector
circuit outputs a cursor control signal representative of the
motion of the object. A control circuit, connected to the display
screen, the electronic appliance, and the motion detector circuit
and supplied with the cursor control signal, controls the display
screen to display a movable visual indicator, e.g. a cursor, whose
own motion tracks the movement of the moving object and the
electronic appliance to perform operations corresponding to the
icons selected by the user using the visual indicator.
[0006] In a preferred embodiment, the motion detector circuit
detects the selection of an icon by the user by detecting a
predetermined motion pattern of the object when the visual
indicator is coincident on the display screen with a particular
icon. For example, the motion detector circuit detects the
selection of an icon by the user by detecting a cessation of
movement of the object for a predetermined period of time after the
visual indicator is coincident on the display screen with a
particular icon. The detected object can be, for example, the
user's hand. The predetermined motion can be a circular hand
movement.
[0007] In the preferred embodiment, the motion detector circuit
includes a video camera and calculates a motion vector of each
macro block between two adjacent video frames in a video output
signal from the video camera. Each video frame includes a plurality
of blocks, each containing vectors representative of detected
motion of the object. Neighbor vectors with almost the same
direction are grouped as one region. For each frame, the motion
detector circuit, in determining whether to track an object, checks
each region to determine if that region satisfies the conditions
(a) that the vector made one rotation clockwise or counterclockwise
and (b) the region returned to the start position where it used to
be and locks onto that region if conditions (a) and (b) are both
satisfied.
[0008] In order that the same general length of hand movement will
control the visual indicator to move a consistent corresponding
length of movement, the control circuit includes an automatic
cursor sensitivity adjustment feature which automatically scales
the extremes of the movement of the visual indicator to the
extremes of the predetermined hand motion so that, for example, the
same diagonal motion of the user's hand will cause the visual
indicator to move just across the diagonal of the display screen
regardless of whether the user is close to the motion detector
circuit or far away.
[0009] A remote controlling method for an electronic appliance
according to the invention includes the steps of visually
displaying on a display screen, such as a TV screen, icons
representing possible operations of the electronic appliance (e.g.
a TV), detecting a motion within a field of view, including
detecting a first predetermined motion of a moving object within
the field of view as an indication that a remote control operation
is to be started and, thereafter, tracking the movement of the
object an outputting a cursor control signal representative of the
motion of the object. In response to the control signal,
controlling the display screen to display a movable visual
indicator, e.g. a cursor, whose movement tracks the movement of the
moving object and further controlling the electronic appliance to
perform operations corresponding to the icons selected by the user
using the visual indicator. The first predetermined motion can be
any hand movement, such as a circular movement or a diagonal hand
movement, for example.
[0010] The step of detecting the selection of an icon by the user
includes detecting a second predetermined motion pattern of the
object when the visual indicator is coincident on the display
screen with a particular icon. For example, the predetermined
motion pattern could be a cessation of movement of the object for a
predetermined period of time after the visual indicator is
coincident on the display screen with the particular icon.
[0011] The motion detecting step uses a video camera in the
preferred embodiment and includes calculating a motion vector of
each macro block between two adjacent video frames in a video
output signal from the video camera. Each video frame includes a
plurality of blocks each containing vectors representative of
detected motion of the object, wherein neighbor vectors with almost
the same direction are grouped as one region. For each frame, the
determination of whether to track an object is made by checking
each region to determine if that region satisfies the conditions
(a) that the vector made one rotation clockwise or counterclockwise
and (b) the region returned to the start position where it used to
be. That region is locked onto if conditions (a) and (b) are both
satisfied.
[0012] In order that the same general length of hand movement will
control the visual indicator to move a consistent corresponding
length of movement, the remote controlling method according to the
invention further includes a step of automatically adjusting the
sensitivity of the visual indicator by the steps of automatically
scaling the extremes of the movement of the visual indicator to the
extremes of the predetermined hand motion so that, for example, the
same diagonal motion of the user's hand will cause the visual
indicator to move just across the diagonal of the display screen
regardless of whether the user is close to the motion detector
circuit or far away.
[0013] The foregoing and other objectives, features and advantages
of the invention will be more readily understood upon consideration
of the following detailed description of certain preferred
embodiments of the invention, taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE INVENTION
[0014] FIG. 1 is a block diagram of the motion sensing remote
control system according to the invention.
[0015] FIG. 2 is a diagrammatic illustration for use in explaining
how the user uses a hand motion to cause the remote control system
of FIG. 1 to recognize that a motion control signal is about to be
made.
[0016] FIG. 3 is a diagrammatic illustration for use in explaining
how the user causes the remote control system of FIG. 1 to move an
on-screen cursor to follow the hand motion of the user.
[0017] FIG. 4 is a diagram of a macro block in a video signal frame
in which a motion is calculated by the remote control system of
FIG. 1 and further depicts motion vectors as arrows.
[0018] FIGS. 5-8 are each snapshots of vectors at an interval of
one half a second.
[0019] FIG. 9 is a snapshot wherein the remote control system of
FIG. 1 has determined that the image is a hand image and locks onto
the image.
[0020] FIG. 10 is a block diagram of an alternative embodiment
which makes use of an MPEG encoder of the electronicl
appliance.
[0021] FIG. 11 is a diagrammatic illustration for use in explaining
how the user uses another type of predetermined hand motion to
cause the remote control system of FIG. 1 to recognize that a
motion control signal is about to be made.
[0022] FIGS. 12 and 13 are each snapshots of macro blocks and
motion vectors at an interval of one half a second of motion
vectors detected by the remote control system of FIG. 1 for a hand
motion shown in FIG. 11.
[0023] FIGS. 14 and 15 depict the user's diagonal hand motion as
detected by the remote control system of FIG. 1 when the user is
close to the TV (FIG. 14) and when the user is far from the TV
(FIG. 15).
[0024] FIG. 16 is an illustration showing how the user cooperates
in setting the automatic cursor sensitivity adjustment control.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] The system according to the invention operates on the
premise that a user does a special hand motion so that, for
example, a TV can easily detect and lock onto an image of the
user's hand. Once the hand image is locked, the TV electronically
follows the hand's motion and moves a cursor on the TV screen
toward the same direction as the hand moves. The user can move the
cursor by moving the hand like a PC mouse. Moving the cursor, the
user can choose a menu button from a plurality of buttons on the TV
display. If the TV loses track of the hand motion after locking,
the TV indicates a message to the user and lets the user do a
special hand motion to re-lock and trace the motion.
[0026] To detect hand moves, motion vectors can be employed. A
motion vector scheme is common in a motion picture experts group
(MPEG) system. If the system has an MPEG encoder, its motion vector
circuits can be shared. A large reduction in costs will then be
possible.
[0027] Referring now to FIG. 1, a block diagram of the system is
shown. The portion from blocks 1 to 12 is the same as a common
digital TV set. The signal received by an antenna 1 is tuned in a
tuner 2, demodulated and error-corrected in a demodulation and
error correction block 3, and de-multiplexed in demultiplexer 4.
Demultiplexed on screen display (OSD) data, video data and audio
data are sent to OSD circuit 5, video decoder 6, and audio decoder
7, respectively. OSD data and the decoded video signal are mixed in
a superimposer 7 and sent to a cathode ray tube (CRT) circuit 8 and
displayed on CRT monitor 9. Decoded audio data is amplified in an
amplifier 11 and sent to a loudspeaker 12.
[0028] Blocks 13 to 16 are the main portion of this invention. A
camera 13, which can be mounted on the monitor 9, for example,
captures images of a user 18 in front of the TV set and sends its
images to a motion detector circuit 15. The motion detector circuit
15 compares the current video frame with a previous video frame
stored in a RAM 14 and calculates a motion vector for each macro
block of the video frame. A macro block size is, for example,
16.times.16 pixels. One frame consists of, for example, 22.times.18
macro blocks.
[0029] When the user 18 wants to control the TV, the user 18 moves
his or her hand 20 in a circular motion, so that it draws a circle
in the air. (FIG. 2). The TV distinguishes this unusual hand motion
from other motions and senses that the user 18 wants to
communicate. At that time, the TV displays the menu button icons 22
on the CRT display. Once the TV's motion detector circuit 15
captures the hand image, the motion detector circuit 15 locks the
hand motion and a cursor 24 follows it. If the user 18 moves his or
her hand 20 to the right, the cursor 24 on the CRT display moves
right (24'). The hand 20 and the cursor 24 behave like a PC mouse
and a cursor. Note that the TV does not care about absolute
position of the hand 20. The TV senses only moving speed and
direction of the hand 20 and moves the on screen cursor 24. When
the cursor 24 comes to a menu button icon 22 the user 18 wants, the
user 18 stops and holds the hand 20 there a couple of seconds. The
motion detector circuit 15 of the TV recognizes this action as the
equivalent of a "button push" and executes the function the button
icon 22 indicates. If no move is detected for a certain time, it is
timed out. The menu disappears. The motion detector circuit 15
begins trying to detect another circular move again.
[0030] The motion detector circuit 15 recognizes and locks the hand
20 image as follows. The motion detector circuit 15 calculates a
motion vector of each macro block between two adjacent frames.
Small vectors below a certain threshold are ignored. FIG. 4 shows
whole macro blocks in a frame. For purposes of explanation and to
make the figure simpler, the depicted macro blocks are less than
the actual number and shown larger. Neighbor vectors with almost
the same direction are grouped as one region. In FIG. 4, regions 1
and 2 are grouped. At this time, the motion detector circuit 15
does not know which region is the hand image. The motion detector
circuit 15 repeats this procedure for every frame.
[0031] In the next frame, if there is a region that has almost the
same position and vector direction as region 1, the region will
succeed the named region 1. Other regions will be named in the same
way. A new region 1 is given a new name. If a region in a previous
frame does not find a successor, it is discarded. Each of FIGS. 5
to 8 indicates a snapshot of vectors at an interval of half a
second. It takes one to three seconds to draw a circle. In FIG. 6,
region 1 disappeared and the motion detector circuit 15 judges
region 1 is not the hand motion. Region 2 is still a candidate for
the hand image. For every frame, the motion detector circuit 15
checks that each region satisfies the following two conditions:
[0032] (1) Did the vector make one rotation clockwise or
counterclockwise?
[0033] (2) Did the region return to the start position where it
used to be?
[0034] If a region meets these conditions, the motion detector
circuit 15 judges it is the hand image.
[0035] In FIG. 8, region 2 is judged as the hand image. Then the
motion detector circuit 15 locks on region 2 and follow its motion
(FIG. 9). The motion detector circuit 15 lets CPU 16 know that the
hand image has been locked and sends its motion information to CPU
16. Controlled by CPU 16, OSD 5 moves the cursor 24 on the CRT
monitor 9 so that the cursor 24 follows the hand motion.
[0036] If the motion detector circuit 15 loses track of the hand
20, the motion detector circuit 15 informs the CPU 16 to cause the
CRT 9 to display the message "Move your hand right". The user 18
follows the message. Then the motion detector circuit 15 causes the
CPU to control the CRT 9 to display another message "Move your hand
upward." The user 18 follows the message again. If the motion
detector circuit 15 captures the image that moves right first and
upward next, then the motion detector circuit 15 re-captures and
locks on the hand image again.
[0037] The special hand motion is not limited to a circular move.
Any other special gesture will do. To let the TV know the menu
button icon 22 is chosen, the user can do another special gesture
instead of holding the hand 20 still. For example, as a variation
of the circular hand motion, the user 18 may move the hand 20
several times (for example twice) toward diagonal direction, for
example, lower left to upper right. (FIG. 11) When the hand 20 goes
up, motion vectors point to the upper right (FIG. 12) region 3).
When the hand 20 goes down, the motion vectors point to the lower
left. (FIG. 13, region 3) The motion vectors point to the opposite
direction as the hand 20 moves. Therefore, if there are motion
vectors which point to a predetermined direction and change their
direction oppositely, for example, three times (predetermined
times) in a certain time period, the system judges that the user 18
has done the predetermined motion and locks onto the hand
motion.
[0038] Compared with the circular motion shown in FIG. 2, this is
an easier motion for the user 18 to make and also easier to detect
for the system. A drawback is that such a motion is more likely to
occur unintentionally than the circular motion and, thus,
misdetection could occur more frequently. If the user 18 jiggles
his or her leg, it could cause misdetection. It is a tradeoff.
[0039] The moving distance of the hand 20 depends on the camera
view angle and the distance between the camera 13 and the user 18.
FIGS. 14 and 15 show a diagonal hand motion in the camera view. If
the view angle is wide or the user 18 is at some distance from the
camera 13, the corresponding distance moved by the cursor 24 on the
display is relatively shorter than it would be if the view angle
was not so wide or the user 18 was closer to the camera 13. (FIG.
14). If the view angle is narrow or the user 18 is too close to the
camera 13, the hand motion distance is large. (FIG. 15). Assume
that the cursor 24 sensitivity is fixed. In the former case, the
cursor 24 moves little even if the user 18 makes a large motion of
his or her hand 20. In the latter case, the cursor 24 is too
sensitive and it moves a relatively large distance in response to a
small hand motion.
[0040] To solve this problem, this system has an auto cursor
sensitivity adjustment function. When the predetermined motion is
small in the camera view, the CPU 16 moves the cursor 24 largely.
When the predetermined motion is large in the camera view, the CPU
16 moves the cursor 24 a little. For example, in FIG. 14, assume
that the predetermined hand motion is 50 pixels long. In this case,
the CPU 16 makes the cursor 24 move 4 pixels when the hand 20 moves
1 pixel, i.e. the cursor motion is automatically scaled to the
length of the detected hand motion. In FIG. 15, the predetermined
hand motion is 200 pixels long. The cursor 24 should move 1 pixel
for every one pixel of hand motion. If the user 18 wants to move
the cursor 24 from the left side to the right side of the display,
the user only should move the hand 20 almost the same distance
regardless of the camera view angle or the user's position from the
camera 13. This auto cursor sensitivity is implemented in the
software of the CPU 16.
[0041] Referring now to FIG. 16, when the user 18 makes a
predetermined motion in the form of a diagonal hand movement, the
motion detection system 15 locks onto the hand movement and moves
the cursor 24 diagonally across the face of the TV screen. CPU 16
always calculates the ratio of the video frame diagonal distance to
the distance of the hand stroke. The cursor is controlled
proportionally to the ratio. If the user 20 controls the length of
his or her hand movement to be constant, the CPU 16 is programmed
to recognize this as the largest hand motion that needs to be
detected and scales the corresponding-movement of the cursor 24 so
that it just spans the entire diagonal of the TV screen. This scale
between the length of hand movement and the length of corresponding
cursor movement is thereafter maintained for other hand movements.
If the recognized diagonal hand stroke was ten inches, after the
hand image is locked, the user 18 has to move the hand 20 ten
inches diagonally in order to move the cursor from the lower left
comer to the upper right comer on the CRT monitor 9. If the
recognized diagonal hand stroke is 20 inches, the user has to move
the hand 20 inches to move the cursor in the same way.
[0042] Instead of a cursor 24, a button may be highlighted like a
digital satellite system graphical user interface (DSS GUI). When
the hand 20 moves up, the upper button icon gets highlighted and so
on. To choose the highlighted button, the user 18 holds the hand 20
on the button for some seconds. As used in this specification and
claims, the term "cursor" is to be deemed to include any change in
the TV display which tracks the movement of the user's detected
motion, including such highlighting of button icons in
correspondence to the motion of the user's hand.
[0043] Instead of motion vector detection, another image
recognition scheme can be employed for this invention. For example,
the motion detector circuit 15 may follow the tracks of skin color
of the hand. If the track draws a circle, the motion detector
circuit 15 judges that it is the hand image. Another way is to
detect an outline of the hand with a pattern-matching scheme. The
most important point of this invention is that a user does a
special predetermined move so that the motion detector circuit 15
can easily distinguish it from other visually "noisy" moves.
[0044] This invention can be applied for not only digital TV, but
also analog TV, PC video-phone, or any system that uses a camera
and monitor display. Not only a CRT but also other kinds of
displays (for example, an LCD, projection TV, etc.) can be
used.
[0045] A video conference or telephone system uses an MPEG or H.261
video encoder. FIG. 11 shows a typical example of the encoder. The
signal from camera 100 is sent via a subtraction node 101 to a DCT
(Discrete Cosine Transform) block 102 for compression. In case of a
predictive frame, before DCT processing, the signal is subtracted
from reconstructed intra frame data in the subtraction block 101.
After DCT processing, the signal is quantized in a circuit block
103 and output as a encoded stream. The output signal is also
de-quantized in a circuit block 104 and uncompressed in an
Inverse-DCT circuit 105. The uncompressed signal is passed through
a summing block 106 and stored in a frame memory 107. In case of a
predictive frame, reconstructed intra frame data is added to the
uncompressed signal in the block 106.
[0046] The motion detector circuit 108 is connected to the frame
memory 107, compares the past frame with the current frame and
calculates a motion vector of each macro block. In this way motion
vectors can be obtained. Therefore, with a small modification, i.e.
detection of whether the vectors of a given region the motion
detector circuit 108 can detect a circular hand motion. The motion
detector circuit 108 sends the hand motion data to CPU 16. The rest
of the blocks (blocks 1 to 12) are the same as in the embodiment of
FIG. 1. Blocks 13 to 15 can be replaced with this modified encoder.
By sharing the motion detection block with the encoder, a circuit
size reduction and a cost reduction will be accomplished.
[0047] As an extended feature, if the camera is motor-driven, the
CPU 16 can control the pan, tilt, or zoom of the camera
automatically so that the hand image is positioned at the best
place (usually the center) in the camera view.
[0048] This system does not require color signals. Therefore, for a
dark place, an infrared camera 13 may be used.
[0049] If the CPU 16 connects with a network interface, for example
a 1394 interface, this system can send hand position data and
control another device through the network. This system does not
have to be built into a TV set.
[0050] Although the present invention has been shown and described
with respect to preferred embodiments, various changes and
modifications are deemed to lie within the spirit and scope of the
invention as claimed. The corresponding structures, materials,
acts, and equivalents of all means or step plus function elements
in the claims which follow are intended to include any structure,
material, or acts for performing the functions in combination with
other claimed elements as specifically claimed.
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