Dynamic Gamut Display Systems, Methods, and Applications Thereof

• US 20140340434A1
• Filed: 08/05/2014
• Published: 11/20/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Ostendo Technologies Inc.
• Original Assignee: Ostendo Technologies Inc.
• Inventors: El-Ghoroury, Hussein S., Lanzone, Andrew J.
• Granted Patent: US 9,524,682 B2
• Time in Patent Office: Days
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2350/00 Solving problems of bandwidth in display systems
• CPC Class Codes: G09G 3/2096 Details of the interface to the display terminal specific for a flat panel suitable for both CRT and flat panel G09G5/006; specific for a CRT G09G1/167
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/04 using circuits for interfacing with colour displays

Abstract

In the dynamic gamut display systems, video input data is processed to extract metrics indicative of the gamut occupancy of the frame pixels. The extracted metrics are used to form a set of scale factors to be used by the display to synthesize an adapted gamut that matches the frame pixel color gamut from the native color primaries of the display. The generated gamut adaptation scale factors are used to convert the frame pixels'"'"' values to the adapted gamut which are provided to the display for modulation using the synthesized adapted gamut for each video frame or a sub-region of a video frame. The methods enable increased display brightness, reduced power consumption and reduced interface and processing bandwidth. Also disclosed is an adapted video frame data formatting method that maps the benefits of the adapted gamut into a reduced frame data size enabling bandwidth savings when used for video distribution.

Claims

1. A dynamic gamut display system method comprising:

buffering in a buffer, an input video frame pixel data expressed relative to a defined three primary reference color gamut having a defined reference white point;

processing the input video frame pixel data as the input video frame pixel data is entered into the buffer to calculate a set of gamut metrics for each processed pixel'"'"'s data;

integrating the set of gamut metrics over a multiplicity of the processed pixel'"'"'s data to calculate a set of gamut scale factors that represent a distribution of processed pixel'"'"'s data color values around the defined reference white point;

calculating an adapted color gamut and a matrix for converting pixels'"'"' color values from the defined three primary reference color gamut to the adapted color gamut using the set of gamut scale factors;

converting the buffered input video frame pixel data from the defined three primary reference color gamut to the adapted color gamut using the matrix to provide adapted frame pixel data; and

outputting the adapted color gamut and the adapted frame pixel data to a display element of the dynamic gamut display system.

2. The method of claim 1 wherein the set of gamut metrics are a set of respective minimum distances from a frame'"'"'s pixels'"'"' chromaticity position to lines extending from the defined reference white point to three color primaries of the defined three primary reference color gamut.

3. The method of claim 2 wherein the set of gamut metrics are converted to normalized gamut metrics values ranging from 0 to 1, with a gamut metric having a value close to 0 being close to the defined reference white point and a gamut metric having a value close to 1 being closer to a respective one of the three primaries of the defined three primary reference color gamut.

4. The method of claim 3 wherein the respective normalized gamut metrics values or the respective minimum distances are assigned a value 0.0 if a line representing the respective minimum distance intersects the respective line extending from the defined reference white point to the respective one of the three color primaries of the defined three primary reference color gamut.

5. The method of claim 3 wherein the normalized gamut metrics values are integrated in a pair of running accumulators for each of three color primaries of the defined three primary reference color gamut, the running accumulators incorporating a pixel counter, an output of a first of each pair of running accumulators representing a mean of the normalized gamut metrics values of the respective one of the three primaries of the defined three primary reference color gamut and an output of a second of each pair of running accumulators representing a spread of the normalized gamut metrics values of the respective one of the three primaries of the defined three primary reference color gamut.

6. The method of claim 5 wherein the set of gamut scale factors are calculated as a minimum of either a value 1 or a sum of the outputs of the two running accumulators to represent a spread of the frame'"'"'s pixels'"'"' chromaticity around the defined reference white point.

7. The method of claim 6 wherein the set of gamut scale factors are used to represent the adapted color gamut that substantially includes the frame'"'"'s pixels'"'"' chromaticity.

8. The method of claim 7 further comprising calculating a 3×

3 matrix using the set of gamut scale factors to convert the buffered input video frame pixel data to adapted frame pixel data in the adapted color gamut and converting the buffered input video frame pixel data to adapted frame pixel data in the adapted color gamut.

9. The method of claim 7 wherein a display native gamut of the display element is not identical to the defined three primary reference color gamut, and further comprising synthesizing the color primaries of the adapted color gamut using the set of gamut scale factors and color primaries of the display native gamut.

10. The method of claim 9 further comprising synthesizing the color primaries of the adapted color gamut using the set of gamut scale factors and the defined three primary reference color gamut, and additional scale factors representing values of a desired display brightness, white point chromaticity and brightness.

12. The method of claim 5 wherein each pair of running accumulators provide their outputs when their pixel counters reach a respective preset maximum value that is either a full pixel count within the buffered input video frame or a pixel count within a sub-region of the buffered input video frame, thus allowing adaptation of the adapted color gamut once per buffered input video frame or multiple times per buffered input video frame.

13. The method of claim 12 wherein the respective preset maximum value of each pair of running accumulators is selected to enable adaptation of a display native gamut multiple times per input video frame to enable the adapted display native gamut to match a gamut of multiple equal or non-equal size sub-regions of the input video frame.

14. The method of claim 5 wherein the running accumulators are configured to provide running accumulator outputs after their pixel counter reaches a preset minimum pixel count value and their accumulated normalized gamut metrics values fall between a predefined set of thresholds that partition a full range of the accumulated normalized gamut metric values into a discrete set of segments to enable the adapted color gamut to match the gamut of multiple non-equal size sub-regions of the input video frame data having different levels of color correlation.

15. The method of claim 10 wherein the color primaries of the adapted color gamut are synthesized by adjusting the turn-on times of the color primaries of the display native gamut by two components, a first component being the values of the color primaries of the display native gamut needed to synthesize the reference color gamut weighted by the additional scale factors, and a second component being values of the display element white point, chromaticity and brightness complementarily weighted by the additional scale factors.

16. The method of claim 15 wherein the display element is a solid state light based display.

17. The method of claim 16 wherein an apparatus for practicing the method is collocated with the solid state light based display.

18. The method of claim 16 wherein the interface apparatus for practicing the method is remotely located from the solid state light based display, and is either embedded within or supplementary to the solid state light based display, whereby the adapted color gamut and the adapted frame pixel data are coupled to the interface apparatus embedded within or supplementary to the solid state light based display via a cable network, a local area network, a mobile wireless network, the Internet, or a batch media.

19. The method of claim 18, wherein the apparatus for practicing the method is either incorporated, co-located or integrated with a video distribution headend that couples the adapted color gamut and the adapted frame pixel data through an interface to a multiplicity of display elements via the Internet, the mobile wireless network, the local area network or a batch media, the multiplicity of display elements including but not limited to the solid state light based display.

20. The method of claim 19, as applied to reduce a bandwidth of the interface.

21. The method of claim 20 wherein the multiplicity of display elements include a display element not capable of adapting its gamut, and wherein a processing function is added to process data frames to decode the respective adapted frame pixel data to convert the adapted frame pixel data to pixels'"'"' data relative to the gamut of the respective display element.

22. The method of claim 16 wherein the adapted color gamut and the adapted frame pixel data are outputted to the solid state light based display in a data stream comprising data frames that convey video frame synchronization data plus a header data sub-frame followed by respective adapted frame pixel data, and wherein:

the header data sub-frame is comprised of two data fields, wherein;

the first data field of the header data sub-frame conveys data needed to synthesize the defined reference color gamut from the display native gamut and set the display operational white point chromaticity and brightness, and

the second data field of the header data sub-frame conveys a set of gamut scale factors, and

a pixels'"'"' data sub-frame conveys the respective adapted frame pixel data.

23. The method of claim 22 wherein the first data field of the header data sub-frame is changed only when the defined three primary reference color gamut or brightness or white point chromaticity of the solid state light based display is changed.

25. The method of claim 22 wherein the second data field of the header data sub-frame is changed each time the defined three primary reference gamut is converted to the adapted color gamut, either each frame or sub-region of each frame and inserted within the pixels'"'"' data sub-frame to convey the video frame or video frame sub-region adapted color gamut.

26. The method of claim 22 wherein the adapted frame pixel data as conveyed by the pixels'"'"' data sub-frame is represented by either the same number of bits as the input video frame pixel data, or a fewer number of bits than the input video frame pixel data as determined by the set of gamut scale factors and conveyed by the second data field of the header data sub-frame.

27. The method of claim 26, used to provide a reduction in a number of bits of the pixels'"'"' data sub-frame that is responsive a reduction in a number of bits representing the adapted color gamut relative to a number of bits of the defined three primary reference color gamut.

29. The method of claim 1, as applied to increase a color representation precision of the display element.

30. The method of claim 1, as applied to reduce interface and processing bandwidth of the display element.

11. The method of clam 10 wherein the display element synthesizes the color primaries of the adapted color gamut and modulates the adapted frame pixel data using the synthesized color primaries of the adapted color gamut.

24. The method of clam 23 wherein a change in the first data field of the header data sub-frame is indicated by a change flag incorporated in the first data field of the header data sub-frame.

28. The method of clam 1, as applied to either increase brightness or reduce a power consumption of the display element.