Using a residual image to represent an extended color gamut digital image

• US 6,282,311 B1
• Filed: 09/28/1998
• Issued: 08/28/2001
• Est. Priority Date: 09/28/1998
• Status: Expired due to Term

• Current Assignee: Monument Peak Ventures, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Eastman Kodak Company
• Inventors: Spaulding, Kevin E., McCarthy, Ann L., Giorgianni, Edward J.
• Primary Examiner(s): Manci, Jose R
• Assistant Examiner(s): Bayat, Ali
• Application Number:
  US09/162,026
• Time in Patent Office: 1,065 Days
• Field of Search: 382/162, 382/167, 382/240, 358/504, 358/520, 358/523, 358/518, 358/1.9, 358/517, 348/431.1, 348/434.1, 345/153, 345/155
• US Class Current: 382/162
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77
• CPC Class Codes: H04N 1/6058 Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut

Abstract

A method for representing a digital image having color values with an extended color gamut in a storage color space having a limited color gamut includes adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image; representing the limited color gamut digital image in the storage color space; determining a residual image representing a difference between the extended color gamut digital image and the limited color gamut digital image; and associating the residual image with the limited color gamut digital image in the storage color space such that the associated residual image and the limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image.

Claims

1. A method for representing a digital image having color values with an extended color gamut in a storage color space having a limited color gamut comprising:

a) adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image;

b) representing the limited color gamut digital image in the storage color space;

c) determining a difference between the extended color gamut digital image and the limited color gamut digital image forming a residual image; and

d) storing the residual image with the limited color gamut digital image in the storage color space such that the associated residual image and the limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image.

2. The method of claim 1 where the storage color space is a particular device dependent color space.

3. The method of claim 2 where the storage color space is a video RGB color space.

4. The method of claim 3 further including previewing the digital image by displaying the limited color gamut digital image in the storage color space on a video display.

5. The method of claim 1 where the storage color space is a particular limited color gamut color space.

6. The method of claim 1 where the limited color gamut digital image is determined by clipping colors that are outside the limited color gamut so that they are on the surface of the limited color gamut.

7. The method of claim 1 where the limited color gamut digital image is determined by using gamut mapping that preserves color appearance.

8. The method of claim 1 where the limited color gamut digital image is determined by modifying color values that are outside the limited color gamut so that they are mapped to color values within the limited color gamut.

9. The method of claim 1 where the extended color gamut digital image has a larger range of chroma values than the limited color gamut digital image.

10. The method of claim 1 where the extended color gamut digital image has a larger luminance dynamic range than the limited color gamut digital image.

11. The method of claim 10 where the adjusting the color values of the extended color gamut digital image to determine the limited color gamut digital image includes applying a tone scale function to reduce the luminance dynamic range of the image.

12. The method of claim 10 wherein the extended luminance dynamic range digital image is a monochrome digital image.

13. The method of claim 1 where the extended color gamut digital image is a representation of the colors in an original scene.

14. The method of claim 13 where the limited color gamut digital image is determined by rendering the colors of the original scene to produce rendered color values that are desirable for a first output device.

15. The method of claim 14 where the residual image is determined by computing the difference between the rendered color values for the first output device and a second set of rendered color values that are desirable for a second output device having a larger color gamut than the first output device.

16. The method of claim 15 where the larger color gamut output device is a hypothetical output device having an idealized color gamut.

17. The method of claim 1 where the limited color gamut digital image in the storage color space is stored in a digital image file using a digital storage medium.

18. The method of claim 17 where the residual image is stored as additional data in the digital image file.

19. The method of claim 17 where a data compression technique is applied to the residual image before it is stored so that it uses a smaller amount of digital storage memory.

20. The method of claim 17 where the limited color gamut digital image is stored in the digital image file, and the residual image is stored in a separate digital image file.

21. The method of claim 1 further including using the residual image together with the limited color gamut digital image in the storage color space to form a reconstructed extended color gamut digital image.

22. The method of claim 1 further including using the residual image together with the limited color gamut digital image in the storage color space to form a digital image appropriate for display on an output device having a color gamut different that the limited color gamut.

23. The method of claim 1 where the extended color gamut digital image originates from a scan of a photographic negative.

24. The method of claim 1 where the extended color gamut digital image originates from a scan of a photographic transparency.

25. The method of claim 1 where the extended color gamut digital image originates from a scan of a photographic print.

26. The method of claim 1 where the extended color gamut digital image originates from a digital camera.

27. The method of claim 1 where the residual image is determined by computing a difference between the extended color gamut digital image represented in an extended storage color space and the limited color gamut digital image represented in the storage color space.

28. A method for representing and manipulating a digital image with an extended color gamut using a storage color space having a limited color gamut comprising:

a) adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image;

b) representing the limited color gamut digital image in the storage color space;

c) determining a difference between the extended color gamut digital image and the limited color gamut digital image forming a residual image;

d) storing the residual image with the limited color gamut digital image in the storage color space such that the associated residual image and the limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image;

e) specifying a desirable modification to the image; and

f) using the residual image together with the limited color gamut digital image in the storage color space and the specified desirable modification to the image to produce a modified digital image.

29. The method of claim 28 where the desirable modification is interactively user specified.

30. The method of claim 28 where the desirable modification is determined by applying an automatic algorithm to the digital image.

31. A method for representing a digital image having color values with an extended color gamut in a storage color space having a limited color gamut comprising:

a) adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image;

b) representing the limited color gamut digital image in the storage color space;

c) compressing the limited color gamut digital image in the storage color space;

d) determining a difference between the extended color gamut digital image and an uncompressed limited color gamut digital image computed from the compressed limited color gamut digital image in the storage color space forming a residual image; and

e) storing the residual image with the compressed limited color gamut digital image in the storage color space such that the associated residual image and the compressed limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image.

32. A computer program product, comprising a computer readable storage medium, for representing a digital image having color values with an extended color gamut in a storage color space having a limited color gamut having a computer program stored thereon for performing:

a) adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image;

b) representing the limited color gamut digital image in the storage color space;

c) determining a difference between the extended color gamut digital image and the limited color gamut digital image forming a residual image; and

d) storing the residual image with the limited color gamut digital image in the storage color space such that the associated residual image and the limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image.

33. A computer program product for representing and manipulating a digital image with an extended color gamut using a storage color space having a limited color gamut, and having a computer readable storage medium with a computer program stored thereon for performing:

a) adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image;

b) representing the limited color gamut digital image in the storage color space;

c) determining a difference between the extended color gamut digital image and the limited color gamut digital image forming a residual image;

d) storing the residual image with the limited color gamut digital image in the storage color space such that the associated residual image and the limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image;

e) specifying a desirable modification to the image; and

f) using the residual image together with the limited color gamut digital image in the storage color space and the specified desirable modification to the image to produce a modified digital image.

34. A computer program product, comprising a computer readable storage medium, for representing a digital image having color values with an extended color gamut in a storage color space having a limited color gamut having a computer program stored thereon for performing:

a) adjusting the color values of the extended color gamut digital image to fit within the limited color gamut to form a limited color gamut digital image;

b) representing the limited color gamut digital image in the storage color space;

c) compressing the limited color gamut digital image in the storage color space;

d) determining a difference between the extended color gamut digital image and an uncompressed limited color gamut digital image computed from the compressed limited color gamut digital image in the storage color space forming a residual image; and

e) storing the residual image with the compressed limited color gamut digital image in the storage color space such that the associated residual image and the compressed limited color gamut digital image in the storage color space are adapted to be used to form a reconstructed extended color gamut digital image.