Systems and methods for accurately representing high contrast imagery on high dynamic range display systems

• US 9,135,864 B2
• Filed: 12/19/2012
• Issued: 09/15/2015
• Est. Priority Date: 05/14/2010
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Shields, Jerome, Hadlaw, Marek, Erinjippurath, Gopal
• Primary Examiner(s): Tzeng, Fred
• Application Number:
  US13/719,412
• Publication Number:
  US 20130106923A1
• Time in Patent Office: 1,000 Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/1333 Constructional arrangements; Manufacturing methodsG02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: H04N 9/3126 for spatial light modulators in series

Abstract

A dual-panel display system is provided that comprises control modules and algorithms to select codeword pairs (CWs) to drive a first image-generating panel and a second contrast-improving panel. The first codewords is selected by considering some characteristics of the input image data (e.g., peak luminance) and to improve some image rendering metric (e.g., reduced parallax, reduced contouring, improved level precision). The first codeword may be selected to be the minimum first codeword within a set of codeword pairs that preserves the peak luminance required by the input image data. Also, the first codeword may be selected to minimize the number of Just Noticeable Difference (JND) steps in the final image to be rendered. The second codeword may be selected to similarly improve image quality according to a given quality metric.

Claims

1. A dual-panel display system comprising:

a backlight;

a first image-generating panel;

a second contrast-improving panel;

a control module for selecting a codeword (CW) pair for driving said first image-generating panel and said second contrast-improving panel respectively according to input image data; and

further wherein said control module is capable of selecting the CW pair to improve final image rendering presented to a viewer.

2. The display according to claim 1, wherein the first image-generating panel comprises a monochrome LCD panel.

3. The display according to claim 2, wherein the second contrast-improving panel comprises a chromatic LCD panel.

4. The display according to claim 3, wherein said control module is capable of selecting a first CW for driving said first image-generating panel from among a set of possible CW pairs that satisfy a desired luminance setting according to input image data.

5. The display according to claim 4, wherein said first CW for driving said first image-generating panel is substantially the minimum CW value among the set of possible CW pairs that satisfy a desired luminance setting according to input image data.

6. The display according to claim 4 wherein said first CW for driving said first image-generating panel is substantially the CW for minimum Just Noticeable Difference (JND) steps among the set of possible CW pairs that satisfy a desired luminance setting according to input image data.

7. The display according to claim 4 wherein said control module is capable of:

selecting a first minimum CW for driving said first image-generating panel that is substantially the minimum CW value among the set of possible CW pairs that satisfy a desired luminance setting according to input image data;

selecting a first minimum JND CW for driving said first image-generating panel is substantially the CW for minimum JND steps among the set of possible CW pairs that satisfy a desired luminance setting according to input image data; and

combining minimum CW image data and minimum JND CW image data according to said first minimum CW image data and said first minimum JND CW image data to select a final first CW for driving said first image-generating panel.

8. The display according to claim 7 wherein said control module is capable of filtering said CW image data by spreading the energy of said CW image data while substantially maintaining the peak energy of the CW image data.

9. The display according to claim 8 wherein said spreading of energy comprises dilating and filtering of said CW image data.

10. The display according to claim 9 wherein said control module is capable of selecting a second CW to drive said second contrast-improving panel according to said first CW selected to drive said first image-generating panel.

11. The display according to claim 10 wherein said second CW is selected among a set of possible second CWs to improve final image rendering presented to a viewer.

12. In a dual-panel display system, said dual-panel display system comprising:

a backlight, a first image-generating panel, a second contrast-improving panel, a method for selecting a codeword (CW) pair for driving said first image-generating panel and said second contrast-improving panel respectively according to input image data;

the steps of said method comprising;

inputting image data to be rendered by said dual-panel display system;

finding a first CW for driving said first image-generating panel based upon input image data; and

finding a second CW for driving said second contrast-improving panel, said first CW and said second CW comprising the CW pair, and wherein the CW pair improves final image rendering according to a desired metric.

13. The method of claim 12 wherein the step of finding a first CW for driving said first image further comprises:

extracting the maximum color component value from the input image data; and

finding a first CW for said first image-generating panel that meets the maximum color component value extracted from the input image data.

14. The method of claim 13 wherein the step of finding a first CW for said first image-generating panel that meets the maximum color component value extracted from the input image data further comprises:

finding the set of possible CW pairs of first CWs and second CWs; and

selecting the first CW that is substantially minimum among the set of possible CW pairs.

15. The method of claim 13 wherein the step of finding a first CW for said first image-generating panel that meets the maximum color component value extracted from the input image data further comprises:

finding the set of possible CW pairs of first CWs and second CWs; and

selecting the first CW that substantially minimizes the JND steps among the set of possible CW pairs.

16. The method of claim 12 wherein the step of finding a first CW for driving said first image generating panel further comprises:

extracting the maximum color component value from the input image data; and

finding the CW for said first image-generating panel that meets the maximum color component value extracted from the input image data and substantially minimizes the JND steps.

17. The method of claim 16 wherein the step of finding the CW for said first image-generating panel that meets the maximum color component value extracted from the input image data and substantially minimizes the JND steps further comprises:

finding the set of possible CW pairs of first CWs and second CWs; and

selecting from the set of possible CW pairs the first CW that substantially minimizes the JND steps.

18. The method of claim 12 wherein said method further comprises the steps of:

finding the minimum CW image data;

finding the minimum JND CW image data; and

combining the minimum CW image data and the minimum JND CW image data to select a first CW.

19. The method of claim 18 wherein said step of combining the minimum CW image and the minimum JND CW image to select a final first CW image further comprises:

filtering the minimum CW image data and the minimum JND CW image data with a narrow filter to create a first intermediate CW image data;

filtering the minimum CW image data and the minimum JND CW image data with a wide filter to create a second intermediate CW image data;

mixing said first intermediate CW image data and said second intermediate CW image data to create a third CW image data.

20. The method of claim 19 wherein the step of mixing said first intermediate CW image data and said second intermediate CW image data to create a third CW data image further comprises:

creating said third CW image data such that said third CW image data comprises energy spread out while substantially maintaining the peak energy derivable from the input image data.

21. The method of claim 12 wherein said method further comprises the steps of:

finding said second CW such that the selected CW pair substantially minimizes JND steps.

22. The method of claim 12 wherein said method further comprises the steps of:

finding said second CW such that the selected CW pair substantially minimizes contouring in said final image presented to a viewer.

23. The method of claim 12 wherein said method further comprises the steps of:

finding said second CW such that the selected CW pair substantially minimizes parallax in said final image presented to a viewer.