Efficient decoding and post-processing of high dynamic range images

• US 8,781,238 B2
• Filed: 09/06/2012
• Issued: 07/15/2014
• Est. Priority Date: 09/08/2011
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Ninan, Ajit, Ten, Arkady
• Primary Examiner(s): Mehta, Bhavesh
• Assistant Examiner(s): Niu, Feng
• Application Number:
  US13/605,368
• Publication Number:
  US 20130064462A1
• Time in Patent Office: 677 Days
• Field of Search: None
• US Class Current: 382/233
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression

Abstract

A decoder receives for decoding and post-processing for display an HDR (high dynamic range) image comprising a first coded image (e.g., a JPEG-HDR baseline image) and a second coded image (e.g., a JPEG-HDR ratio image). The first coded image is partially decoded and post-processed according to a post-processing command (e.g., scaling) to output a first decoded and post-processed image. The second coded image is also partially decoded and post-processed according to the post-processing command to output a second decoded and post-processed image. The first and the second decoded and post-processed images are combined to output a decoded HDR image according to the post-processing command.

Claims

1. A method to combine decoding and post-processing of a coded HDR image with a processor, the method comprising:

accessing the coded HDR (high dynamic range) image, the HDR image comprising a JPEG-coded baseline image and a second coded image, wherein the JPEG-coded baseline image comprises a plurality of 8×

8 coded baseline image blocks and the second coded image comprises a plurality of coded regions;

partially decoding the JPEG-coded baseline image according to a post-processing command for the HDR image to output a first decoded image, wherein the partial decoding of the first coded image comprises;

performing an N×

N IDCT (Inverse Discrete Cosine Transform) on each one of the plurality of the coded 8×

8 baseline blocks, where N is a positive integer smaller than 8 but larger or equal to 1;

partially decoding the second coded image according to the post-processing command to output a second decoded image; and

combining the first decoded image and the second decoded image to output a decoded and post-processed HDR image.

2. The method of claim 1, wherein the post-processing command comprises at least one of an image down-scaling command, an image up-scaling command, and an image windowing command.

3. The method of claim 1, wherein the second coded image comprises a JPEG-coded ratio image comprising a plurality of coded ratio image blocks.

4. The method of claim 3, wherein decoding the JPEG-coded ratio image comprises performing an N×

N IDCT on each one of the plurality of the coded ratio blocks, where N comprises a positive integer smaller than 8 but larger or equal to 1.

5. The method of claim 4, wherein N has a value that is equal to 1, 2, or 4.

6. The method of claim 1, wherein N has a value that is equal to 1, 2, or 4.

7. The method of claim 1, further comprising:

before the combining step, applying second post-processing to the first decoded image according to the post-processing command to generate a post-processed first decoded image, wherein the combining step comprises combining the post-processed first decoded image and the second decoded image.

8. The method of claim 1, further comprising:

before the combining step, applying third post-processing to the second decoded image according to the post-processing command to generate a post-processed second decoded image, wherein the combining step comprises combining the post-processed second decoded image and the first decoded image.

9. The method of claim 1, further comprising:

before the combining step, applying second post-processing to the first decoded image according to the post-processing command to generate a post-processed first decoded image; and

applying third post-processing to the second decoded image according to the post-processing command to generate a post-processed second decoded image, wherein the combining step comprises combining the post-processed first decoded image and the post-processed second decoded image.

10. A non-transitory computer-readable storage medium having stored thereon computer-executable instructions for executing a method with a processor according to the method of claim 1.

11. A method to decode a coded HDR image with a processor, the method comprising:

accessing the coded HDR (high dynamic range) image comprising a JPEG-coded baseline image and a coded ratio image, wherein the JPEG-coded baseline image comprises a first plurality of 8×

8 coded baseline image blocks, and the coded ratio image comprises a second plurality of coded ratio image blocks;

decoding the JPEG-coded baseline image according to a post-processing command to output a first decoded image, wherein decoding the JPEG-coded baseline image comprises performing an N×

N IDCT (Inverse Discrete Cosine Transform) on each one of the plurality of the coded 8×

8 baseline blocks, where N is a positive integer smaller than 8 but larger or equal to 1;

decoding the coded ratio image according to the post-processing command to output a second decoded image; and

combining the first decoded image and the second image to output a decoded and post-processed HDR image.

13. The method of claim 11, wherein N has a value that is equal to 1, 2, or 4.

12. A method to decode a coded HDR image with a processor, the method comprising:

accessing the coded HDR (high dynamic range) image comprising a JPEG-coded baseline image and a coded ratio image, wherein the JPEG-coded baseline image comprises a first plurality of 8×

8 coded baseline image blocks, and the coded ratio image comprises a second plurality of coded ratio image blocks;

decoding the JPEG-coded baseline image according to a post-processing command to output a first decoded image;

decoding the coded ratio image according to the post-processing command to output a second decoded image, wherein decoding the coded ratio image comprises performing an N×

N IDCT on each one of the plurality of the coded ratio blocks, where N comprises a positive integer smaller than 8 but larger or equal to 1; and

combining the first decoded image and the second image to output a decoded and post-processed HDR image.

14. The method of claim 12, wherein N has a value that is equal to 1, 2, or 4.