Displaying images on local-dimming displays
Displays, display components, image and video processing apparatus and related methods are described. A method for driving local-dimming displays comprises generating control values for driving pixels of a spatial light modulator from one image data component and generating control values for driving backlight elements from a second image data component. The first and second image data components may respectively comprise a tone map and a ratio image. Control values for the spatial light modulator and/or backlight may be obtained using cost effective hardware.
1. Apparatus for driving a local-dimming display comprising a backlight and a spatial light modulator, the backlight comprising a plurality of individually-controllable elements, the apparatus comprising:
a decoder configured to:
receive, from an encoder, image data comprising (i) a first image data component comprising a low-dynamic range version of an image; and (ii) a second image data component comprising values that can be used to modify the low-dynamic range version of the image to recover a high-dynamic range version of the image, wherein the low-dynamic range version of the image is a tone-mapped image of the high-dynamic range version of the image, and wherein the values that can be used to modify the low-dynamic range version of the image are linearized ratio data; and
extract, from the image data, the first image data component and the second image data component;
a first system configured to generate, using the first image data component and without using the high-dynamic range version of the image, first driving signals for the spatial light modulator; and
a second system configured to:
combine the tone-mapped image and the linearized ratio data by multiplying values in the tone-mapped image by corresponding values in the linearized ratio data to generate a high-dynamic range image;
extract luminance values of the high-dynamic range image;
down-sample the luminance values of the high-dynamic range image to generate down-sampled data and
generate, using the second image data component and without using the high-dynamic range version of the image, second driving signals for controlling the individually controllable elements of the backlight by generating the second driving signals based on the down-sampled data.
2. Apparatus according to claim 1 wherein the second system comprises a downsampler configured to down-sample the luminance values of the high-dynamic range image to generate down-sampled data.
3. Apparatus according to claim 1 wherein the second system comprises a driving value calculator configured to normalize the second image data component.
4. Apparatus according to claim 3 wherein the driving value calculator is configured to normalize the second image data component by dividing values of the second image data by a representative value.
5. Apparatus according to claim 4 wherein the representative value comprises a maximum value, mean value, average value, median value, or percentile value.
6. Apparatus according to claim 4 wherein the driving value calculator is configured to clip the values of the second image component to the representative value.
7. Apparatus according to claim 1 wherein the second system comprises a linearizer.
8. Apparatus according to claim 1 wherein the first system comprises:
a light field simulator configured to generate an estimated light field that would be produced at the spatial light modulator upon applying the second driving signals to drive the backlight; and
a tone map modifier configured to modify the tone-mapped image according to the estimated light field.
9. Apparatus according to claim 1 wherein the second image data component has a resolution lower than a resolution of the first image data component.
10. Apparatus according to claim 1 wherein the first system comprises a color correction stage.
11. Apparatus according to claim 1 wherein the first system comprises a sharpening filter.
12. Apparatus according to claim 1 , wherein the first system is further configured to generate the first driving signals based on the second image data component.
13. A method for driving a local-dimming display comprising a backlight and a spatial light modulator, the backlight comprising a plurality of individually-controllable elements, the method comprising:
obtaining, from an encoder, image data comprising (i) a first image data component comprising a low-dynamic range version of an image; and (ii) a second image data component comprising values that can be used to modify the low-dynamic range version of the image to recover a high-dynamic range version of the image, wherein the low-dynamic range version of the image is a tone-mapped image of the high-dynamic range version of the image, and wherein the values that can be used to modify the low-dynamic range version of the image are linearized ratio data;
extracting, from the image data, the first image data component and the second image data component;
generating, using the first image data component and without using the high-dynamic range version of the image, first driving signals for the spatial light modulator;
combining the tone-mapped image and the linearized ratio data by multiplying values in the tone-mapped image by corresponding values in the linearized ratio data to generate a high-dynamic range image;
extracting luminance values of the high-dynamic range image;
down-sampling the luminance values of the high-dynamic range image to generate down-sampled data; and
generating, using the second image data component and without using the high-dynamic range version of the image, second driving signals for controlling the individually controllable elements of the backlight by generating the second driving signals based on the down-sampled data.
14. A method according to claim 13 comprising clipping values of the second image data to a reference value.
15. A method according to claim 13 wherein the second image data component has a resolution lower than a resolution of the first image data component.
16. A method according to claim 13 wherein generating the second driving signals comprises linearizing the second image data component.
17. A method according to claim 13 wherein generating the first driving signals comprises applying a sharpening filter to the first image data component.
18. A method according to claim 13 wherein generating the first driving signals comprises applying a color correction to the first image data component.
19. A display apparatus comprising:
a backlight comprising a plurality of individually controllable elements;
a spatial light modulator configured to receive light from the plurality of individually controllable elements of the backlight;
a decoder configured to:
receive, from an encoder, image data comprising (i) a first image data component comprising a low-dynamic range version of an image; and (ii) a second image data component comprising values that can be used to modify the low-dynamic range version of the image to recover a high-dynamic range version of the image, wherein the low-dynamic range version of the image is a tone-mapped image of the high-dynamic range version of the image, and wherein the values that can be used to modify the low-dynamic range version of the image are linearized ratio data; and
extract, from the image data, first image data component and the second image data component;
a first system configured to generate, using the first image data component and without using the high-dynamic range version of the image, first driving signals for the spatial light modulator; and
a second system configured to:
combine the tone-mapped image and the linearized ratio data by multiplying values in the tone-mapped image by corresponding values in the linearized ratio data to generate a high-dynamic range image;
extract luminance values of the high-dynamic range image;
down-sample the luminance values of the high-dynamic range image to generate down-sampled data; and
generate, using the second image data component and without using the high-dynamic range version of the image, second driving signals for controlling the individually controllable elements of the backlight by generating the second driving signals based on the down-sampled data.
20. Apparatus for driving a local-dimming display comprising a backlight and a spatial light modulator, the backlight comprising a plurality of individually-controllable elements, the apparatus comprising:
a decoder configured to:
receive, from an encoder, image data comprising (i) a first image data component comprising a tone-mapped image of a high-dynamic range version of the image; and (ii) a second image data component comprising linearized ratio data that can be used to modify the tone-mapped image to recover the high-dynamic range version of the image; and
extract, from the image data, the first image data component and the second image data component;
a first system configured to:
combine the tone-mapped image and the linearized ratio data by multiplying values in the tone-mapped image by corresponding values in the linearized ratio data to generate a high-dynamic range image; and
generate, based on the generated high-dynamic range image, first driving signals for the spatial light modulator; and
a second system configured to generate, using the second image data component and without using the high-dynamic range version of the image, second driving signals for controlling the individually controllable elements of the backlight.
21. A method for driving a local-dimming display comprising a backlight and a spatial light modulator, the backlight comprising a plurality of individually-controllable elements, the method comprising:
obtaining, from an encoder, image data comprising (i) a first image data component comprising a tone-mapped image of a high-dynamic range version of the image; and (ii) a second image data component comprising linearized ratio data that can be used to modify the tone-mapped image to recover the high-dynamic range version of the image;
extracting, from the image data, the first image data component and the second image data component;
combining the tone-mapped image and the linearized ratio data by multiplying values in the tone-mapped image by corresponding values in the linearized ratio data to generate a high-dynamic range image;
generating, based on the generated high-dynamic range image, first driving signals for the spatial light modulator; and
generating, using the second image data component and without using the high-dynamic range version of the image, second driving signals for controlling the individually controllable elements of the backlight.
22. A display apparatus comprising:
a backlight comprising a plurality of individually controllable elements;
a spatial light modulator configured to receive light from the plurality of individually controllable elements of the backlight;
a decoder configured to:
receive, from an encoder, image data comprising (i) a first image data component comprising a tone-mapped image of a high-dynamic range version of the image; and (ii) a second image data component comprising linearized ratio data that can be used to modify the tone-mapped image to recover the high-dynamic range version of the image; and
extract, from the image data, the first image data component and the second image data component;
a first system configured to:
combine the tone-mapped image and the linearized ratio data by multiplying values in the tone-mapped image by corresponding values in the linearized ratio data to generate a high-dynamic range image; and
generate, based on the generated high-dynamic range image, first driving signals for the spatial light modulator; and
a second system configured to generate, using the second image data component and without using the high-dynamic range version of the image, second driving signals for controlling the individually controllable elements of the backlight.