HDR displays and control systems therefor

1. A controller connected to control a first array of pixels and a second array of pixels according to image data defining a desired image, the first and second arrays of pixels each comprising a plurality of controllable elements, the controller configured to:

control the controllable elements of the first array of pixels to project a pattern of light which approximates the desired image onto the second array of pixels; and,

control the controllable elements of the second array of pixels to reduce a difference between the pattern of light and the desired image.

2. A controller according to claim 1 wherein the controller is configured to:

determine intensities of the pattern of light at the controllable elements of the second array of pixels; and,

control the controllable elements of the second array of pixels in response to the determined intensities.

3. A controller according to claim 1 wherein for each controllable element of the first array of pixels, the second array of pixels has more than one controllable element, and wherein the controller is configured to:

set each controllable element of the first array of pixels to contribute a luminance which is an average, or weighted average, of a plurality of desired luminance values for image areas corresponding to that controllable element of the first array of pixels.

4. A controller according to claim 1 wherein the controller is configured to:

control the controllable elements of the second array of pixels to modulate light incident thereon based on desired luminance values at image locations corresponding to locations of the controllable elements of the second array of pixels divided by intensities of light from the first array of pixels at the controllable elements of the second array of pixels.

5. A controller according to claim 1 wherein the controller is configured to:

set each controllable element of the first array of pixels to a brightness level selected from a number N of discrete brightness levels; and

set each controllable element of the second array of pixels to a brightness level selected from a number M of discrete brightness levels, wherein N is greater than M.

6. A controller according to claim 1 wherein the controller is configured to:

set each controllable element of the first array of pixels to a brightness level selected from a number N of discrete brightness levels; and

set each controllable element of the second array of pixels to a brightness level selected from a number M of discrete brightness levels, wherein N is less than M.

7. A controller according to claim 1 wherein the controllable elements of the second array of pixels have controllable retro-reflection properties, and wherein the controller is configured to control the controllable elements of the second array of pixels by adjusting retro-reflection properties of the controllable elements of the second array of pixels.

8. A controller according to claim 1 wherein the controllable elements of the second array of pixels have controllable transmission properties, and wherein the controller is configured to control the controllable elements of the second array of pixels by adjusting transmission properties of the controllable elements of the second array of pixels.

9. A controller according to claim 1 wherein the first array of pixels comprises an array of color pixels, wherein the controller is configured to control the controllable elements of the first array of pixels by separately setting a color value for each controllable element of the first array of pixels.

10. A controller according to claim 9 wherein the controller is configured to control the controllable elements of the first array of pixels by separately setting a plurality of color values for each controllable element of the first array of pixels.

11. A controller according to claim 1 wherein the controller is configured to:

control the controllable elements of the second array of pixels to modulate light incident thereon by locally dimming areas of the second array of pixels which correspond to image areas where the desired image has reduced desired luminance values.

12. The controller according to claim 1 , wherein the control of the first and second arrays of pixels includes control that reduces artifacts that result from a variance in resolution between the first and second arrays of pixels.

13. The controller according to claim 12 , wherein the second array of pixels comprises pixels of a transmissive panel and the control that reduces artifacts is provided according to an algorithm that sets control levels for the controllable elements of the first array of pixels to provide an approximation of the desired image by determining an average of desired luminance values for image areas corresponding to pixels of the transmissive panel.

14. The controller according to claim 13 , wherein the average comprises a weighted average of the desired luminance values.

15. A controller configured to,

produce signals capable of controlling a display, the signals comprising control values to be applied to a backlight and cause local dimming in the backlight and controlling transmissivity of a display panel illuminated by the locally-dimmed backlight,

wherein,

the signals are produced based on an image signal,

the local dimming is enabled by providing, in the signals, a control level for each of a plurality of individually-controllable lights of the backlight that cause the backlight to produce a low resolution version of a desired image contained in the image signal,

the transmissivity of the display panel is enabled by providing, in the signals, modulation data for the display panel that is intended to be used to modulate light emanating from the locally-dimmed backlight so as to reduce differences between the low resolution version of the desired image and the desired image, and

the modulation data including artifact minimization.

16. The controller according to claim 15 , wherein the artifact minimization comprises a minimization of artifacts related to differences in resolution between the backlight and the panel.

17. The controller according to claim 15 , wherein the control levels for each of a plurality of individually-controllable lights of the backlight comprise a light intensity level selected in coarser steps than that of a light intensity in the modulation data for the panel.

18. The controller according to claim 15 , wherein the control levels for each of a plurality of individually controllable lights of the backlight are intended to control a backlight having comparatively lower resolution than the transmissive array.

19. The controller according to claim 18 , wherein the transmissive array comprises an LCD panel.

20. A means for controlling a display, comprising:

means for energizing a backlight to produce a low resolution version of a desired image;

means for energizing a transmissive panel illuminated by the backlight with modulation data to effect changes in the low resolution version of the image so as to approach the desired image;

wherein:

the backlight has a lower resolution than the transmissive panel;

the means for energizing the transmissive panel includes means for reducing artifacts caused by the mismatch in resolutions between the backlight and the transmissive panel;

the means for energizing the backlight comprises means for adjusting a light intensity of the backlight comprising means for stepwise adjustments of the light intensity; and

the means for energizing the transmissive panel further including means for adjusting transmissivity of the transmissive panel, the means for adjusting transmissivity of the transmissive panel comprising means for stepwise adjustments in transmissivity of a resolution finer than that of the means for stepwise adjustments of the light intensity.

21. The means for controlling a display according to claim 20 , wherein the means for energizing a backlight and the means for energizing a transmissive panel comprise a computer means comprising image processing means.