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Digital Camera Patent Abstract
A processor-based system may be controlled using a digital camera.
The digital camera can provide luminance and motion information
which may be analyzed to determine whether to alter one or more
of the power consumption state, the operation of system utilities,
or the operation of a screen saver.
Digital Camera Patent Claims
1. A processor-based system comprising: a processor, said processor
coupled to a storage device; a digital camera coupled to said processor;
and said storage device storing software that controls the power
consumption state of said system based on information received from
said camera.
2. The system of claim 1 wherein said software controls the power
consumption state of said system based on information from said
camera indicative of motion proximate to said camera.
3. The system of claim 1 wherein said software controls the operation
of system utilities based on information from said digital camera.
Digital Camera Patent Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application
Ser. No. 09/430,282, filed on Oct. 29, 1999.
BACKGROUND
[0002] This invention relates generally to processor-based systems
and particularly to such systems which have a digital camera coupled
to the system.
[0003] A variety of processor-based systems come with a digital
camera or are adaptable to be coupled to a digital camera. Commonly,
digital cameras are tethered through an appropriate input port to
personal computers. A number of users operate the digital cameras
continuously through a tethered connection to the computer.
[0004] The camera may be maintained always "on", ready
to provide a useful service as the opportunity arises. The camera
may be used to implement a video conferencing feature or to stream
video over the Internet as examples.
[0005] A number of techniques are available for controlling processor-based
systems. Processor-based systems may receive input commands using
a mouse which is tethered to the computer, using an infrared mouse
which controls the computer remotely, using a variety of remote
control devices, and using keyboards either tethered to the computer
or keyboards that are coupled to the computer through infrared or
other airwave communications, as a few examples.
[0006] In addition, a number of computer systems transition between
power consumption states in response to periods of sustained user
inactivity. That is, if the keyboard, for example, is not operated
for a given time period, the system may transition to a lower power
consumption state. With ensuing periods of inactivity, the system
may progressively transition to even lower power consumption states.
In this way, the amount of power that the system consumes may be
controlled. In addition to environmental advantages, the lifetime
of the computer may be enhanced by such powering down in response
to inactivity.
[0007] Sensors may detect the user's presence in proximity to the
keyboard. These sensors may be piezoelectric sensors that detect
when the user is poised over the keyboard, for example. Again, this
type of sensor provides additional information to the computer system
to make a judgment about whether or not to transition to lower power
consumption modes. If the user is poised over the keyboard about
to operate the keyboard, it makes no sense to transition to a lower
power consumption mode only to immediately transition back to a
higher power consumption mode. Not only is this awkward, but needless
transitions waste time and system resources.
[0008] Thus, there is a continuing need for better ways to control
the power consumption of computer systems.
SUMMARY
[0009] In accordance with one aspect, a method of controlling a
processor-based system includes receiving video information from
a camera. The power consumption state of the system is controlled
based on the video information.
[0010] Other aspects are set forth in the accompanying detailed
description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a front elevational view of a processor-based
system in accordance with one embodiment of the present invention;
[0012] FIG. 2 is a flow chart for software for implementing one
aspect of one embodiment of the present invention;
[0013] FIG. 3 is a flow chart for software for implementing another
aspect of one embodiment of the present invention;
[0014] FIG. 4 is a flow chart for software for implementing another
aspect of one embodiment of the present invention;
[0015] FIG. 5 is a flow chart for software that implements another
aspect of one embodiment of the present invention; and
[0016] FIG. 6 is a block diagram for the embodiment shown in FIG.
1.
DETAILED DESCRIPTION
[0017] A processor-based system 10 shown in FIG. 1, includes a
processor-based housing 12, a keyboard 13, a display 14 and a digital
camera 16 which may be coupled by a tether (not shown) to the housing
12. As illustrated, the camera 16 is positioned to observe the area
in front of the processor-based system 10. Thus, the camera 16 detects
the user's presence as well as the lighting conditions proximate
to the system 10.
[0018] Referring now to FIG. 2, light monitoring software 18 stored
on the system 10, is responsible for controlling the power consumption
state of the processor-based system 10 in response to ambient light.
A timer is reset (block 20) and the keyboard and mouse are checked
for their current condition (block 22). At diamond 24, a check determines
whether the keyboard and mouse have just been used. If so, the timer
is again reset. If not, the check at diamond 26 determines whether
the timer has expired. If the timer has expired, indicating a period
of inactivity exceeding a predetermined time period, a video frame
is grabbed as indicated in block 28. In other words, the camera
16 provides a video frame which may be analyzed at block 30. In
particular, the luminance value of the frame may be computed at
block 30.
[0019] A subsampling of the pixels of a frame may be analyzed,
for example, approximately 250 pixels in one embodiment of the invention,
evenly distributed throughout the frame. Each pixel's luminance
value is computed by converting its red, green, blue (RGB) color
space value to a hue, saturation and luminance (HSL) color space
value using well known techniques. Luminance is the brightness portion
of a composite video signal. The pixel luminance values are simply
summed and divided by the number of samples. The result is the return
luminance value.
[0020] Referring to FIG. 3, the software 42 for determining the
return luminance value begins by taking the video frame as described
previously (see block 44). The pixel stepping for the pre-set sample
set, approximately 250 pixel samples in this example, is computed
(block 46). The software steps to the next pixel location (block
48). The pixel at the next location has its RGB color space values
converted to an HSL format (blocks 50 and 52). The luminance value
of the next pixel (from the HSL space) is added to the accumulated
luminance total value, as indicated in block 54. If there are more
pixels to complete the sample set, the flow iterates. If not, the
luminance total is divided by the number of pixel samples as indicated
in block 58. The result is then returned to the flow in FIG. 2,
as indicated at block 60.
[0021] Returning to FIG. 2, next the motion value is computed (block
32). As shown in FIG. 4, software 62 for computing the return motion
value begins by taking the video frames from the previous steps
(FIG. 2) as indicated at block 64. The pixel stepping for a pre-set
number of pixels, for example approximately 250 pixels, is computed,
as indicated in block 66. The flow steps through each successive
pixel as indicated in block 68. At block 70, the pixel at the new
location in the old frame and new frame are accessed. The red value
in the old frame is subtracted from the red value in the new frame
and this process is repeated for the blue and green values as indicated
in block 72. An absolute value of the difference is computed (block
74).
[0022] If the result is greater than 50 or some other noise threshold
(diamond 76), the result is added to the total motion return value
(block 78). At diamond 80 a determination is made as to whether
there are additional pixels in the initial set of 250 pixel samples.
If not, the motion value is returned (block 82). Otherwise, the
flow continues to iterate until all the pixels in the sample have
been processed.
[0023] Returning again to FIG. 2, at diamond 34 the flow determines
whether the returned luminance value differs by more than 40 percent.
Of course, 40 percent is merely an exemplary threshold for testing
the returned luminance value. If so, a check at diamond 36 determines
whether this is the fourth time (or some other number) in a row
that the luminance value remained at this level. If so, a check
at diamond 38 determines whether motion has occurred during the
time period. If not, appropriate changes can be made as indicated
in block 40. Among the changes that may be made are to activate
a screen saver, implement a power management decision or implement
a system utility.
[0024] Once the camera 16 is activated, it may capture a frame
every second in one embodiment of the invention. The system 10 computes
the luminance value for each frame and compares its value to the
luminance value computed for a previous frame. If the number is
significantly lower than that of previous frames, the software starts
to suspect the lights might be out. It keeps capturing frames, computing
both a luminance value and a motion value. If the luminance value
continues to be low for several frames and the motion value is also
low, the computer screen saver and power management mode may be
activated. When full power management is turned on, a keyboard or
mouse input signal may be used to reactivate the computer. However,
the camera 16 can continue to run with the monitors, printers and
hard drives powered down, as long as the processor remains on.
[0025] The camera continues to capture frames while the computer
is in the lower power usage mode or screen saver mode. It compares
the frames and computes the luminance value for each frame. If the
luminance suddenly increases, the system is immediately returned
to full power status and/or the screen saver is deactivated. If
the luminance values do not change significantly, and motion occurs
for a time period (for example continuously for three seconds),
the system may be returned to full power status and/or the screen
saver may be deactivated.
[0026] Turning now to FIG. 5, the software 84 for leaving the screen
saver, power management, or system utility modes begins by checking
the keyboard and mouse status (block 86). At diamond 88, a check
determines whether the keyboard or mouse was just used. If so, the
computer is returned to full operational status as indicated in
block 102. The timer is reset, as indicated in block 104, and the
keyboard and mouse states are checked (block 106).
[0027] At diamond 108, a check determines whether the keyboard
or mouse were just used. If not, the flow determines (at diamond
110) whether the timer has expired. If so, the screen saver, power
management mode or system utilities may be reactivated, as indicated
in block 112. Otherwise, the system continues to check the keyboard
and mouse state, as indicated in block 106.
[0028] If the keyboard and mouse were not used as determined at
diamond 88, a video frame is grabbed as shown in block 90. A luminance
value and motion value are computed as indicated in blocks 92 and
94. If the luminance value does not differ by a preset amount (for
example more than 40% at diamond 96), a check at diamond 98 determines
whether motion has occurred. If so, a check at diamond 100 determines
whether motion has occurred two times in a row. If so, the system
returns to full activation (block 102). If not, the flow returns
to block 86 and checks keyboard and mouse states.
[0029] Referring now to FIG. 6, the system 10 may include a processor
114 coupled to an interface 116. The interface 116 may be a chipset
or bridge, as two examples. The interface 116 may be coupled system
memory 118 and a display controller 122. The display controller
is coupled to the display 14.
[0030] The interface 116 may also couple a bus 126. The bus 126
in turn may be coupled through an interface 128 to the camera 16.
In addition, the bus 126 may couple an interface 132. The interface
132 may be coupled to a bus 136 and to a storage device such as
a hard disk drive 134. The software 18, 42, 62 and 84 may be stored
on the hard disk drive 134.
[0031] The bus 136 is coupled to conventional components such as
a serial input/output device 138. The device 138 couples a mouse
142 and a keyboard 13. The basic input/output system (BIOS) 144
may also be provided on the bus 136.
[0032] While the present invention has been described with respect
to a limited number of embodiments, those skilled in the art will
appreciate numerous modifications and variations therefrom. It is
intended that the appended claims cover all such modifications and
variations as fall within the true spirit and scope of this present
invention. |