Method and apparatus for encoding and decoding HDR images

Patent metadata

Field	Value
Publication number	US-11727548-B2
Application number	US-202016784124-A
Country	US
Kind code	B2
Filing date	Feb 6, 2020
Priority date	Feb 26, 2014
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

To encode High Dynamic Range (HDR) images, the HDR images can be converted to Low Dynamic Range (LDR) images through tone mapping operation, and the LDR images can be encoded with an LDR encoder. The present principles formulates a rate distortion minimization problem when designing the tone mapping curve. In particular, the tone mapping curve is formulated as a function of the probability distribution function of the HDR images to be encoded and a Lagrangian multiplier that depends on encoding parameters. At the decoder, based on the parameters indicative of the tone mapping function, an inverse tone mapping function can be derived to reconstruct HDR images from decoded LDR images.

First claim

The invention claimed is:

1. A method comprising:
determining a tone mapping function based on images and at least one encoding parameter;
determining a lower dynamic range version of the images from the images based on the tone mapping function;
encoding the lower dynamic range version of the images and information including a parameter used to encode the determined lower dynamic range version of the images, wherein the parameter is used as an input to generate an inverse tone-mapping function; and
transmitting the encoded lower dynamic range version of the images and information in one or more signals.

2. The method of claim 1 , wherein the parameter used to encode the lower dynamic range version of the images is a quantization parameter.

3. The method of claim 2 , further comprising determining a Lagrangian multiplier depending on the quantization parameter.

4. The method of claim 1 , wherein determining a tone mapping function comprises determining at least one of the dynamic range of the images and a probability distribution function of the images.

5. The method of claim 1 , wherein determining the tone mapping function is based on a rate distortion function.

6. The method of claim 1 , further comprising providing the one or more signals signal for storage.

7. The method of claim 1 , further comprising interleaving the data in the one or more signals.

8. The method of claim 1 , further comprising randomizing energy in the one or more signals.

9. The method of claim 1 , further comprising modulating the one or more signals from one or more carriers.

10. The method of claim 1 , further comprising error-correction encoding the one or more signals.

11. A method comprising:
receiving one or more signals;
decoding second images depicting a lower dynamic range version of first images from the one or more received signals;
accessing information from the one or more received signals, the accessed information including a parameter used to encode the second images;
using the parameter as an input when generating an inverse tone mapping function; and
generating the first images from the decoded second images based on the inverse tone mapping function.

12. The method of claim 11 , wherein the parameter used to encode the second image is a quantization parameter.

13. The method of claim 11 , wherein the accessed information includes parameters indicative of the dynamic range of original first images corresponding to the first images to be decoded.

14. The method of claim 11 , wherein the accessed information further includes parameters indicative of a probability distribution function of original first images corresponding to the first images to be decoded.

15. The method of claim 11 , further comprising demodulating the one or more received signals from one or more carriers.

16. The method of claim 11 , further comprising de-randomizing energy in the one or more received signals.

17. The method of claim 11 , further comprising de-interleaving the data in the one or more received signals.

18. The method of claim 11 , further comprising error-correction decoding the one or more received signals.

19. A data transmission apparatus comprising:
a tone curve estimator configured to determine a tone mapping function based on images and at least one encoding parameter;
an image generator configured to determine a lower dynamic range version of the images from the images based on the tone mapping function; and
an encoder configured to encode the lower dynamic range version of the images and information including a parameter used to encode the determined lower dynamic range version of the images, wherein the parameter is used as an input to generate an inverse tone-mapping function; and
a transmitter configured to transmit the encoded lower dynamic range version of the images and information in one or more signals.

20. The data transmission apparatus of claim 19 , wherein the parameter used to encode the lower dynamic range version of the images is a quantization parameter.

21. The data transmission apparatus of claim 19 , wherein the tone curve estimator determines a Lagrangian multiplier responsive to the quantization parameter.

22. The data transmission apparatus of claim 19 , wherein the tone curve estimator determines at least one of the dynamic range of the images and a probability distribution function of the images.

23. The data transmission apparatus of claim 19 , wherein the tone curve estimator determines the tone mapping function responsive to a rate distortion function.

24. The data transmission apparatus of claim 19 , further comprising an interleaver configured to interleave the data in the one or more signals.

25. The data transmission apparatus of claim 19 , further comprising a randomizer configured to randomize energy in the one or more signals.

26. The data transmission apparatus of claim 19 , further comprising a modulator configured to modulate the one or more signals.

27. The data transmission apparatus of claim 19 , further comprising an error-correction encoder configured to error-correction encoding the one or more signals.

28. The data transmission apparatus of claim 19 , further comprising or interfacing with an antenna.

29. The data transmission apparatus of claim 19 , wherein the data transmission apparatus is disposed in a cell phone, a computer, a set-top box, or other device that transmits encoded video and provides encoded video signals for at least one of display, processing, and storage.

30. The data transmission apparatus of claim 19 , wherein the data transmission apparatus is communicatively coupled to a storage unit and configured to provide the one or more signals for storage.

31. The data transmission apparatus of claim 30 , wherein the storage unit is coupled to the encoder.

32. The data transmission apparatus of claim 30 , wherein the storage unit is coupled to the transmitter.

33. The data transmission apparatus of claim 30 , wherein the storage unit is one or more of a standard DVD, a Blu-Ray disc, a hard drive, or other storage device.

34. The data transmission apparatus of claim 19 , wherein the transmitter comprises or interfaces with an antenna.

35. A data receiving apparatus comprising:
a receiver configured to provide one or more signals;
a decoder configured to decode second images depicting a lower dynamic range version of first images from the one or more received signals;
a processor configured to:
access information from the one or more signals, the accessed information including a parameter used to encode the second images;
use the parameter as an input when generating an inverse tone mapping function; and
an image generator configured to generate the first images from the decoded second images based on the inverse tone mapping function.

36. The data receiving apparatus of claim 35 , wherein the parameter used to encode the second image is a quantization parameter.

37. The data receiving apparatus of claim 35 , wherein the accessed information includes parameters indicative of the dynamic range of original first images corresponding to the first images to be decoded.

38. The data receiving appara

Assignees

• Interdigital Vc Holdings Inc

Inventors

• Le Pendu Mikael
• Boitard Ronan
• Guillemot Christine
• Thoreau Dominique

Classifications

• H04N19/19

  using optimisation based on Lagrange multipliers · CPC title

• H04N19/124

  Quantisation · CPC title

• H04N19/177

  the unit being a group of pictures [GOP] · CPC title

• H04N19/172

  the region being a picture, frame or field · CPC title

• G06T5/92 Primary

  based on global image properties · CPC title