High dynamic range, backwards-compatible, digital cinema

• US 9,781,417 B2
• Filed: 10/07/2014
• Issued: 10/03/2017
• Est. Priority Date: 06/13/2011
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Ninan, Ajit, Hulyalkar, Samir N.
• Primary Examiner(s): Motsinger, Sean
• Application Number:
  US14/508,026
• Publication Number:
  US 20150023433A1
• Time in Patent Office: 1,092 Days
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 5/40 using histogram techniques
• CPC Class Codes: H04N 19/33 in the spatial domain
• 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 19/647 using significance based coding, e.g. Embedded Zerotrees of Wavelets [EZW] or Set Partitioning in Hierarchical Trees [SPIHT]
• CPC Class Codes: H04N 19/85 using pre-processing or post-processing specially adapted for video compression
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/41415 involving a public display, viewable by several users in a public space outside their home, e.g. movie theatre, information kiosk

Abstract

HDR images are coded and distributed. An initial HDR image is received. Processing the received HDR image creates a JPEG-2000 DCI-compliant coded baseline image and an HDR-enhancement image. The coded baseline image has one or more color components, each of which provide enhancement information that allows reconstruction of an instance of the initial HDR image using the baseline image and the HDR-enhancement images. A data packet is computed, which has a first and a second data set. The first data set relates to the baseline image color components, each of which has an application marker that relates to the HDR-enhancement images. The second data set relates to the HDR-enhancement image. The data packets are sent in a DCI-compliant bit stream.

Claims

1. A method, comprising:

receiving a data packet in a bit stream that conforms to the Digital Cinema Systems Specification of the Digital Cinema Initiative (DCI Systems Standard), the data packet comprising at least a portion of a high dynamic range (HDR) image, wherein the HDR image comprises (a) a coded baseline image that complies with the DCI Systems Standard, and (b) one or more HDR-enhancement images;

wherein the coded baseline image comprises at least three color components, wherein the coded baseline image and the one or more HDR-enhancement images each provides enhancement information to allow reconstruction of an instance of the received HDR image using the baseline image and the HDR-enhancement images;

processing the data packet to reconstruct the HDR image by extracting;

a first data set that relates to the coded baseline image for the at least three color components; and

a second data set that relates to the one or more HDR-enhancement images,

wherein each of the HDR enhancement images comprises;

a first coded chroma residual image,

a second coded chroma residual image, and

a coded ratio image representing ratios of (i) luminance values of the HDR image and (ii) corresponding luminance values of a tone-mapped version of the HDR image,

wherein each of the residual images is configured to capture chroma information lost in creating the baseline image from the HDR image,

wherein the first coded chroma residual image and the second coded chroma residual image are based on the tone-mapped version of the HDR image and a re-mapped image representing an application of the ratios to the HDR image, and

wherein the first coded chroma residual image is embedded within a first portion of the data packet that also includes baseline data for a first color component, the second coded chroma residual image is embedded within a second portion of the data packet that also includes baseline data for a second color component, and the coded ratio image is embedded within a third portion of the data packet that also includes baseline data for a third color component.

2. The method of claim 1, wherein the coded baseline image comprises a resolution of 2048×

1080 (2K), or 4096×

2160 (4K).

3. The method of claim 1, wherein the third portion of the data packet comprises an application marker that separates the baseline data for the third color component and the coded ratio image.

4. The method of claim 1, wherein the first portion of the data packet comprises an application marker that separates the baseline data for the first color component and the first coded chroma residual image.

5. The method of claim 1, wherein the second portion of the data packet comprises an application marker that separates the baseline data for the second color component and the second coded chroma residual image.

6. The method of claim 3, wherein the application marker conforms to a specification of the JPEG 2000 compressor/decompressor (codec) of the Joint Photographic Experts Group (JPEG).

7. The method of claim 1, wherein processing the data packet further comprises:

extracting quantization parameters relating to quantized values for the coded ratio image and the coded residual images for the one or more HDR-enhancement images;

converting, based at least in part on the quantization parameters, the quantized values into the coded ratio image and the coded residual images for the at least three color components; and

reconstructing the HDR image using the coded baseline image as well as the coded ratio image and the code residual images for the at least three color components.

8. An apparatus comprising a processor, wherein the processor is configured to:

receive a computed data packet in a bit stream that conforms to the Digital Cinema Systems Specification of the Digital Cinema Initiative (DCI Systems Standard), the data packet comprising at least a portion of a high dynamic range (HDR) image, wherein the HDR image comprises (a) a coded baseline image that complies with the DCI Systems Standard, and (b) one or more HDR-enhancement images;

wherein the coded baseline image comprises at least three color components, wherein the coded baseline image and the one or more HDR-enhancement images each provides enhancement information to allow reconstruction of an instance of the received HDR image using the baseline image and the HDR-enhancement images;

process the data packet to create the HDR image by extracting;

a first data set that relates to the coded baseline image for the at least three color components; and

a second data set that relates to the one or more HDR-enhancement images,

wherein each of the HDR enhancement images comprise;

a first coded chroma residual image,

a second coded chroma residual image, and

a coded ratio image representing ratios of (i) luminance values of the HDR image and (ii) corresponding luminance values of a tone-mapped version of the HDR image,

wherein each of the residual images is configured to capture chroma information lost in creating the baseline image from the HDR image,

wherein the first coded chroma residual image and the second coded chroma residual image are based on the tone-mapped version of the HDR image and a re-mapped image representing an application of the ratios to the HDR image, and

wherein the first coded chroma residual image is embedded within a first portion of the data packet that also includes baseline data for a first color component, the second coded chroma residual image is embedded within a second portion of the data packet that also includes baseline data for a second color component, and the coded ratio image is embedded within a third portion of the data packet that also includes baseline data for a third color component.

9. The apparatus of claim 8, wherein the coded baseline image comprises a resolution of either 2048×

1080 (2K), or 4096×

2160 (4K).

10. The apparatus of claim 8, wherein the third portion of the data packet comprises an application marker that separates the baseline data for the third color component and the coded ratio image, and wherein the application marker conforms to a specification of the JPEG 2000 compressor/decompressor (codec) of the Joint Photographic Experts Group (JPEG).

11. The apparatus of claim 8, wherein the first portion of the data packet comprises an application marker that separates the baseline data for the first color component and the coded ratio image, and wherein the application marker conforms to a specification of the JPEG 2000 compressor/decompressor (codec) of the Joint Photographic Experts Group (JPEG).

12. The apparatus of claim 8, wherein the processor is further configured to:

extract quantization parameters relating to quantized values for the coded ratio image and the coded residual images for the one or more HDR-enhancement images;

convert, based at least in part on the quantization parameters, the quantized values into the coded ratio image and the coded residual images for the at least three color components; and

reconstruct the HDR image using the coded baseline image as well as the coded ratio image and the code residual images for the at least three color components.

13. A method, comprising:

receiving a high dynamic range (HDR) image;

processing the received HDR image, wherein the received HDR image comprises (a) a coded baseline image that complies with the Digital Cinema Systems Specification of the Digital Cinema Initiative (DCI Systems Standard), and (b) one or more HDR-enhancement images are created from the received HDR image;

wherein the coded baseline image comprises at least three color components, wherein the coded baseline image and the one or more HDR-enhancement images each provide enhancement information to allow reconstruction of an instance of the received HDR image using the baseline image and the HDR-enhancement images;

computing a data packet, wherein the data packet comprises;

a first data set that relates to the coded baseline image for the at least three color components; and

a second data set that relates to the HDR-enhancement images,

wherein each of the HDR enhancement images comprises;

a first coded chroma residual image,

a second coded chroma residual image, and

a coded ratio image representing ratios of (i) luminance values of the received HDR image and (ii) corresponding luminance values of a tone-mapped version of the received HDR image,

wherein the first coded chroma residual image and the second coded chroma residual image are based on the tone-mapped version of the received HDR image and a re-mapped image representing an application of the ratios to the received HDR image

wherein the first coded chroma residual image is embedded within a first portion of the data packet that also includes baseline data for a first color component, the second coded chroma residual image is embedded within a second portion of the data packet that also includes baseline data for a second color component, and the coded ratio image is embedded within a third portion of the data packet that also includes baseline data for a third color component; and

sending the computed data packet in a bit stream that conforms to the DCI Systems Standard.

14. The method of claim 13 wherein the coded baseline image comprises a resolution of 2048×

1080 (2K), or 4096×

2160 (4K).

15. The method of claim 13, wherein the third portion of the data packet comprises an application marker that separates the baseline data for the third color component and the coded ratio image.

16. The method of claim 13, wherein the first portion of the data packet comprises an application marker that separates the baseline data for the first color component and the first coded chroma residual image.

17. The method of claim 13, wherein the second portion of the data packet comprises an application marker that separates the baseline data for the second color component and the second coded chroma residual image.

18. The method of claim 17, wherein the application marker conforms to a specification of the JPEG 2000 compressor/decompressor (codec) of the Joint Photographic Experts Group (JPEG).

19. The method of claim 13, wherein computing the data packet comprises:

generating the tone-mapped image based on the received HDR image;

generating the coded ratio image by dividing luminance values of the received HDR image with the corresponding luminance values of the tone-mapped version of the received HDR image;

applying the luminance ratio values to the received HDR image to create the re-mapped image; and

determining the first coded chroma residual image and the second coded chroma residual image based on the re-mapped image and the tone-mapped image.

20. The method of claim 19, wherein computing the data packet further comprises:

prior to dividing the luminance values of the received HDR image with the luminance values of the tone-mapped image, applying an inverse gamma correction to the tone-mapped image according to a gamma curve for the at least three color components.