Methods and devices for generating, encoding or decoding images with a first dynamic range, and corresponding computer program products and computer-readable medium

1. A method comprising:

obtaining an epitome of an image with a first dynamic range, called a first epitome, the first epitome is a representation of the image with the first dynamic range having reduced redundant information,

determining an epitome of an image with a second dynamic range, called a second epitome, from the image with the second dynamic range, the second epitome is a representation of the image with the second dynamic range having reduced redundant information, and the second dynamic range is lower than the first dynamic range,

determining a transformation map between the second epitome and the image with the second dynamic range,

applying the transformation map to the first epitome, to generate a reconstructed image of the image with the first dynamic range.

2. The method according to claim 1 , wherein the generating the reconstructed image further comprises up sampling the image with the second dynamic range, in order to generate an up sampled image with the first dynamic range.

3. The method according to claim 1 , wherein it comprises at least one iteration of:

obtaining an estimated image with the second dynamic range, from the image with the first dynamic range for a first iteration, or from a corrected image with the first dynamic range for the following iterations,

determining an estimation error between the image with the second dynamic range and the estimated image with the second dynamic range, and

correcting the image with the first dynamic range, responsive to the estimation error, to obtain the corrected image with the first dynamic range.

4. A method for decoding comprising:

decoding an image with a second dynamic range,

obtaining an epitome of an image with a first dynamic range, called a first epitome, the first epitome is a representation of the image with the first dynamic range having reduced redundant information, and the second dynamic range is lower than the first dynamic range,

determining an epitome of the image with the second dynamic range, called a second epitome, from the image with the second dynamic range, the second epitome is a representation of the image with the second dynamic range having reduced redundant information,

determining a transformation map between the second epitome and the image with the second dynamic range,

applying the transformation map to the first epitome, to generate a reconstructed image of the image with the first dynamic range.

5. The method according to claim 4 , wherein the generating the reconstructed image further comprises up sampling the image with the second dynamic range, in order to generate an up sampled image with the first dynamic range.

6. The method according to claim 4 , wherein it comprises at least one iteration of:

obtaining an estimated image with the second dynamic range, from the image with the first dynamic range for a first iteration, or from a corrected image with the first dynamic range for the following iterations,

determining an estimation error between the image with the second dynamic range and the estimated image with the second dynamic range, and

correcting the image with the first dynamic range, responsive to the estimation error, to obtain the corrected image with a first dynamic range.

7. A device comprising at least one memory and one or more processors, the one or more processor being configured to:

obtain an epitome of an image with a first dynamic range, called a first epitome, the first epitome is a representation of the image with the first dynamic range having reduced redundant information,

determine an epitome of an image with a second dynamic range, called a second epitome, from the image with the second dynamic range, the second epitome is a representation of the image with the second dynamic range having reduced redundant information, and the second dynamic range is lower than the first dynamic range

determine a transformation map between the second epitome and the image with the second dynamic range,

apply the transformation map to the first epitome, to generate a reconstructed image of the image with the first dynamic range.

8. The device according to claim 7 , wherein the one or more processor are further configured to up sample the image with the second dynamic range, in order to generate an up sampled image with the first dynamic range.

9. A device for decoding comprising at least one memory and one or more processors, the one or more processor being configured to:

decode an image with a second dynamic range,

obtain an epitome of an image with a first dynamic range, called a first epitome, the first epitome is a representation of the image with the first dynamic range having reduced redundant information, and the second dynamic range is lower than the first dynamic range,

determine an epitome of the image with the second dynamic range, called a second epitome, from the image with the second dynamic range, the second epitome is a representation of the image with the second dynamic range having reduced redundant information, determine a transformation map between the second epitome and the image with the second dynamic range,

apply the transformation map to the first epitome, to generate a reconstructed image of the image with the first dynamic range.

10. The device according to claim 9 , wherein the one or more processor are further configured to up sample the image with the second dynamic range, in order to generate an up sampled image with the first dynamic range.

11. A non-transitory computer-readable medium comprising computer program instructions recorded thereon and capable of being executed by a processor for implementing a method comprising:

obtaining an epitome of an image with a first dynamic range, called a first epitome, the first epitome is a representation of the image with the first dynamic range having reduced redundant information,

determining an epitome of an image with a second dynamic range, called a second epitome, from the image with the second dynamic range, the second epitome is a representation of the image with the second dynamic range having reduced redundant information, and the second dynamic range is lower than the first dynamic range,

determining a transformation map between the second epitome and the image with the second dynamic range,

applying the transformation map to the first epitome, to generate a reconstructed image of the image with the first dynamic range.

12. The device according to claim 11 , wherein the generating the reconstructed image further comprises up sampling the image with the second dynamic range, in order to generate an up sampled image with the first dynamic range.