Adjusting a brightness of a display based on an image

1. A computer-implemented method comprising:

obtaining an image;

determining an amount of brightness in the image;

determining an amount of contrast in the image, including determining an amount of dark pixels in the image and an amount of light pixels in the image satisfies contrast level criteria for a particular contrast level;

determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image;

adjusting the brightness of the display based on the brightness gain; and

providing the image for output on the display with the brightness of the display adjusted in accordance with the brightness gain.

2. The computer-implemented method of claim 1 , wherein adjusting the brightness of the display based on the brightness gain comprises:

increasing the brightness of the display without changing data that represents the image.

3. The computer-implemented method of claim 1 , wherein adjusting the brightness of the display based on the brightness gain comprises:

increasing an amount of power provided to the display based on the brightness gain.

4. The computer-implemented method of claim 1 , wherein providing the image for output on the display with the brightness of the display adjusted in accordance with the brightness gain comprises:

generating a local tone mapped image from the image; and

providing the local tone mapped image for output on the display with the brightness of the display adjusted in accordance with the brightness gain.

5. The computer-implemented method of claim 1 , wherein determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image comprises:

determining an amount of brightness of an environment of the display; and

determining the brightness gain that reflects the amount to adjust brightness of the display based on (i) the amount of brightness in the image, (ii) the amount of contrast in the image, and (iii) the amount of brightness of the environment of the display.

6. The computer-implemented method of claim 1 , wherein determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image comprises:

determining an adjusted amount of brightness in the image based on the amount of contrast in the image; and

determining the brightness gain from the adjusted amount of brightness in the image.

7. The computer-implemented method of claim 1 , wherein determining an amount of brightness in the image comprises:

determining an average of brightnesses of each pixel in the image.

8. The computer-implemented method of claim 1 , wherein determining an amount of contrast in the image comprises:

determining an amount of variance in brightnesses for pixels in the image.

9. The computer-implemented method of claim 1 , wherein determining an amount of dark pixels and an amount of light pixels in the image satisfies contrast level criteria for a particular contrast level comprises:

determining a high amount of contrast in the image in response to determining a percentage of pixels that are dark in the image and a percentage of pixels that are light in the image are both greater than a particular threshold.

10. The computer-implemented method of claim 1 , wherein determining an amount of dark pixels and an amount of light pixels in the image satisfies contrast level criteria for a particular contrast level comprises:

determining a low amount of contrast in the image based on determining a percentage of pixels that are dark in the image is less than a particular threshold and the percentage of pixels that are light in the image is above the particular threshold.

11. The computer-implemented method of claim 1 , wherein determining an amount of dark pixels and an amount of light pixels in the image satisfies contrast level criteria for a particular contrast level comprises:

determining a medium amount of contrast in the image in response to determining a percentage of pixels that are dark in the image is less than a particular threshold and the percentage of light pixels is less than the particular threshold.

12. The computer-implemented method of claim 1 , comprising:

determining that the image is no longer to be output on the display; and

in response to determining that the image is no longer to be output on the display, adjusting the brightness of the display to the brightness of the display before the image was output.

13. A system comprising:

one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:

obtaining an image;

determining an amount of brightness in the image;

determining an amount of contrast in the image, including determining an amount of dark pixels in the image and an amount of light pixels in the image satisfies contrast level criteria for a particular contrast level;

determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image;

adjusting the brightness of the display based on the brightness gain; and

providing the image for output on the display with the brightness of the display adjusted in accordance with the brightness gain.

14. The system of claim 13 , wherein adjusting the brightness of the display based on the brightness gain comprises:

increasing the brightness of the display without changing data that represents the image.

15. The system of claim 13 , wherein adjusting the brightness of the display based on the brightness gain comprises:

increasing an amount of power provided to the display based on the brightness gain.

16. The system of claim 13 , wherein providing the image for output on the display with the brightness of the display adjusted in accordance with the brightness gain comprises:

generating a local tone mapped image from the image; and

providing the local tone mapped image for output on the display with the brightness of the display adjusted in accordance with the brightness gain.

17. The system of claim 13 , wherein determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image comprises:

determining an amount of brightness of an environment of the display; and

determining the brightness gain that reflects the amount to adjust brightness of the display based on (i) the amount of brightness in the image, (ii) the amount of contrast in the image, and (iii) the amount of brightness of the environment of the display.

18. The system of claim 13 , wherein determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image comprises:

determining an adjusted amount of brightness in the image based on the amount of contrast in the image; and

determining the brightness gain from the adjusted amount of brightness in the image.

19. A non-transitory computer-readable medium storing instructions executable by one or more computers which, upon such execution, cause the one or more computers to perform operations comprising:

obtaining an image;

determining an amount of brightness in the image;

determining an amount of contrast in the image, including determining an amount of dark pixels in the image and an amount of light pixels in the image satisfies contrast level criteria for a particular contrast level;

determining a brightness gain that reflects an amount to adjust brightness of a display based on both the amount of brightness in the image and the amount of contrast in the image;

adjusting the brightness of the display based on the brightness gain; and

providing the image for output on the display with the brightness of the display adjusted in accordance with the brightness gain.