Histogram and spatial-based power savings
Described herein are systems and methods that reduce power consumption for an electronics device that includes a display. Power conservation systems and methods described herein alter video information in one or more inactive portions of a display area such that the alteration decreases power consumption. The invention finds use with many electronics devices, such as portable computing devices powered from a battery or other limited source of power. Since video output often dominates power consumption for an electronics device, decreasing display power consumption may extends battery longevity for the portable device.
1. A method for reducing power consumed by a display device, the method comprising:
displaying an active graphics component in a first portion of a display area provided by the display device;
in response to user inactivity in an inactive portion of the display area that is outside the first portion, altering video information in the inactive portion using a histogram manipulation of luminance values for a set of pixels in the inactive portion such that the display device will consume less power when displaying the altered video information than an amount of power that would be required to display the video information without the alteration,
wherein altering the video information includes a) altering the luminance values using a histogram compression of a histogram to produce compressed luminance values, and
b) reducing the compressed luminance values using a constant,
and wherein a) and b) occur at a threshold inactivity time; and
simultaneously displaying the active graphics component in the first portion and the altered video information in the inactive portion.
2. The method of claim 1 wherein the histogram is compressed only on one side of a mean, median or mode for the pixel values.
3. The method of claim 2 wherein the histogram is compressed only for pixel values greater than the mean, median or mode for the pixel values.
4. The method of claim 1 further comprising repeating a) and b) at multiple subsequent power reduction intervals.
5. The method of claim 4 further comprising stopping the repetition of a) and b) when a new luminance histogram produced by a) and b) for the set of pixels reaches a minimum width.
6. The method of claim 4 further comprising stopping the repetition of a) and b) when a maximum luminance in a new luminance histogram produced by a) and b) reaches a predetermined minimum luminance.
7. The method of claim 1 wherein the active graphics component outputs video information for one of: a word processing program, an Internet Browser interface, a graphics control, a music player program, and a video game.
8. The method of claim 1 wherein the alteration reduces one of a red, green, or blue value for the set of pixels in the inactive portion such that the display device will consume less power when displaying the altered video information.
9. The method of claim 1 wherein the constant includes a function of one of i) a maximum luminance for the inactive portion, ii) a maximum luminance provided by the display device, iii) a mean, median or mode of luminance values for an inactive portion, and iv) a mean, median or mode of a luminance range values provided by the display device.
10. The method of claim 1 wherein the constant includes less than 1 percent of the maximum luminance for the inactive portion or the maximum luminance provided by the display device.
11. The method of claim 1 wherein the histogram manipulation substantially maintains relative luminance levels in the video information that existed before the alteration without turning the video information to black.
12. A computer readable medium including instructions for reducing power consumed by a display device, the computer-readable medium comprising:
displaying an active graphics component in a first portion of a display area provided by the display device;
instructions for, in response to user inactivity in an inactive portion of the display area that is outside the first portion, altering video information in the inactive portion using a histogram manipulation of luminance values for a set of pixels in the inactive portion such that the display device will consume less power when displaying the altered video information than an amount of power that would be required to display the video information without the alteration,
wherein the instructions for altering the video information include a) instructions for altering the luminance values using a histogram compression of a histogram to produce compressed luminance values, and
b) instructions for reducing the compressed luminance values using a constant,
and instructions for altering the video information at a threshold inactivity time; and
instructions for simultaneously displaying the active graphics component in the first portion and the altered video information in the inactive portion.
13. A method for reducing power consumed by a display device, the method comprising:
displaying an active graphics component in a first portion of a display area provided by the display device;
in response to user inactivity in an inactive portion of the display area that is outside the first portion, altering video information in the inactive portion using a histogram manipulation of luminance values for a set of pixels in the inactive portion such that the display device will consume less power when displaying the altered video information than an amount of power that would be required to display the video information without the alteration; and
simultaneously displaying the active graphics component in the first portion and the altered video information in the inactive portion.
14. The method of claim 13 wherein the histogram manipulation includes a histogram compression of a histogram including the pixel values and produces compressed pixel values.
15. The method of claim 14 further comprising reducing the compressed pixel values using a constant.
16. The method of claim 13 wherein the alteration reduces one of a red, green, or blue value for the set of pixels in the inactive portion such that the display device will consume less power when displaying the altered video information.
17. The method of claim 13 wherein the alteration reduces a backlight level for the set of pixels in the inactive portion.
18. The method of claim 13 wherein the histogram manipulation includes a histogram shift of a histogram of the pixel values using a constant.
19. The method of claim 18 wherein the constant value includes a function of one of i) a maximum luminance for the inactive portion, ii) a maximum luminance provided by the display device, iii) a mean, median or mode of luminance values for an inactive portion, and iv) a mean, median or mode of a luminance range values provided by the display device.
20. The method of claim 13 wherein the histogram manipulation substantially maintains relative luminance levels that existed before the alteration in the video information for the set of pixels in the inactive portion.