ZONE-BASED TONE MAPPING

• US 20120113130A1
• Filed: 06/29/2010
• Published: 05/10/2012
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: InterDigital Madison Patent Holdings (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Zhai, Jiefu, Llach, Joan
• Granted Patent: US 9,087,382 B2
• Time in Patent Office: Days
• US Class Current: 345/589
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 5/94 based on local image properties, e.g. for local contrast enhancement

Abstract

A method of tone mapping high dynamic range images for display on low dynamic range displays wherein a high dynamic range image is first accessed. The high dynamic range image is segmented into different regions such that each region is represented by a matrix, where each element of the matrix is a weight or probability of a pixel. An exposure of each region is determined or calculated and the exposure values are applied to the regions responsive to the weight or probability. The different regions are then fused together to obtain a final tone mapped image.

Claims

1. A method of tone mapping high dynamic range images for display on low dynamic range displays comprising the steps of:

accessing a high dynamic range image;

segmenting the high dynamic range image into different regions such that each region is represented by a matrix, where each element of the matrix is a weight or probability of a pixel;

determining or calculating exposure of each region;

applying exposure values to the regions responsive to the weight or probability; and

fusing the different regions together to obtain a final tone mapped image.

2. The method of claim 1, further comprising the step of identifying or establishing different perceptual brightness levels for the high dynamic range images.

3. The method of claim 1, further comprising the step of identifying or establishing different perceptual brightness levels for the final tone mapped image.

4. The method of claim 1, further comprising the step of determining regions responsive to luminance data.

5. The method of claim 4, further comprising establishing anchor values, wherein each anchor value establishes one of the regions.

6. The method of claim 1, wherein tone mapping is performed based on a luminance channel and then applied to color channels by post-processing.

7. The method of claim 1, wherein tone mapping is performed based on individual color channels.

8. A method of tone mapping high dynamic range images for display on low dynamic range displays comprising the steps of:

accessing a high dynamic range image;

segmenting the high dynamic range image into different regions such that each region is represented by a matrix, where each element of the matrix is a weight or probability of a pixel;

determining or calculating exposure of each region;

applying exposure values to the regions responsive to the weight or probability;

fusing the different regions together to obtain a final tone mapped image; and

providing a user interface for the user to adjust parameters in the steps.

9. The method of claim 8, further comprising the step of identifying or establishing different perceptual brightness levels for the high dynamic range images.

10. The method of claim 8, further comprising the step of identifying or establishing different perceptual brightness levels for the final tone mapped image.

11. The method of claim 8, further comprising the step of determining regions responsive to luminance data.

12. The method of claim 11, further comprising establishing anchor values, wherein each anchor value establishes one of the regions.

13. The method of claim 8, wherein tone mapping is performed based on a luminance channel and then applied to color channels by post-processing.

14. The method of claim 8, wherein tone mapping is performed based on individual color channels.