Composite color transformation using customized gamut mappings

• US 6,704,442 B2
• Filed: 11/15/1999
• Issued: 03/09/2004
• Est. Priority Date: 11/15/1999
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Newman, Todd D., Haikin, John S.
• Primary Examiner(s): Johns, Andrew W.
• Assistant Examiner(s): Alavi, Amir
• Application Number:
  US09/440,065
• Publication Number:
  US 20030053682A1
• Time in Patent Office: 1,576 Days
• Field of Search: 382/162, 382/163, 382/164, 382/165, 382/166, 382/167, 382/276, 382/168, 395/131, 395/164, 395/162, 358/504, 358/505, 358/518, 358/519, 358/520, 358/521, 358/522, 358/523, 345/430, 345/431
• 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 1/603 controlled by characteristics of the picture signal generator or the picture reproducer
• CPC Class Codes: H04N 1/6058 Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut
• CPC Class Codes: H04N 1/6086 by scene illuminant, i.e. conditions at the time of picture capture, e.g. flash, optical filter used, evening, cloud, daylight, artificial lighting, white point measurement, colour temperature
• CPC Class Codes: H04N 1/6088 by viewing conditions, i.e. conditions at picture output

Abstract

A color management system that transforms input image data from an input colorant space to an output colorant space using input and output device appearance transforms and a customizable gamut mapping algorithm. The gamut mapping algorithm is customizable based on the color management session in question, and in particular may be customizable based on the content of the image data, based on a comparison between input device appearance transforms and output device appearance transforms, or based on viewing conditions, output conditions or print media involved. According to the invention, the customizable gamut mapping algorithm is customized based on the current color management session, and the customized gamut mapping algorithm is composited with the input device appearance transform and/or the output device appearance transform thereby yielding one or more transformations that can be applied to the input image data more efficiently than if the transformations (including the gamut mapping algorithm) were applied individually.

Claims

1. A color management method using an input device appearance transform and an output device appearance transform together with a customizable gamut mapping algorithm, said method comprising the steps of:

obtaining the input device appearance transform and the output device appearance transform based on each of input device color profile and an output device color profile;

customizing the gamut mapping algorithm based on information in regard to the gamut mapping;

compositing the customized gamut mapping algorithm with either the input device appearance transform and a color appearance model transform or the output device appearance transform and an inverse color appearance model transform, or both;

generating an appearance look-up table; and

transforming image data from an input colorant space to an output colorant space using the composited transform,

wherein said gamut mapping algorithm operates in a perceptual color space, said perceptual color space is obtained by using the color appearance model transform.

2. A method according to claim 1, wherein said customizing step customizes the gamut mapping algorithm based on the image data.

3. A method according to claim 1, further comprising the step of comparing between input and output device gamuts, wherein the information on the gamut mapping is the information on the result from the comparison.

4. A method according to claim 1, wherein the information in regard to the gamut mapping is information on the viewing condition.

5. A method according to claim 1, wherein the input device profile and the output device profile include gamut boundary descriptors, and wherein the customizing step customizes based on the gamut boundary descriptors.

6. Computer-executable process steps stored on a computer readable medium, said computer-executable process steps for transforming image data from an input colorant space to an output colorant space by using a composited transform of either the input device appearance transform and a color appearance model transform or the output device appearance transform and an inverse color appearance model transform, or both, said computer-executable process steps comprising process steps executable to perform a method according to claim 1.

7. A computer-readable medium which stores computer-executable process steps, the computer-executable process steps for transforming image data from an input colorant space to an output colorant space by using a composited transform of either the input device appearance transform and a color appearance model transform or the output device appearance transform and an inverse color appearance model transform, or both, said computer-executable process steps comprising process steps executable to perform a method according to claim 1.

8. A color management system which uses an input device appearance transform and an output device together with a customizable gamut mapping algorithm, said system comprising:

an obtaining processor that obtains the input device appearance transform and the output device appearance transform based on each of an input device color profile and an output device color profile;

a customization processor that customizes the customizable gamut mapping algorithm based on information in regard to gamut mapping;

a pre-processor that composites either the input device appearance transform and a color appearance model transform or the output device appearance transform and an inverse color appearance model transform, or both using the customized gamut mapping algorithm, and generates an appearance look-up table; and

a data processor that transforms the image data from an input colorant space to an output colorant space using the composited transform,

wherein the gamut mapping algorithm operates in a perceptual color space, said perceptual color space is obtained by using the color appearance model transform.

9. A color management method using an input device appearance transform and an output device appearance transform together with a customizable gamut mapping algorithm, said method comprising the steps of:

obtaining input device color profile and output device color profile, the input device color profile and the output device color profile each include a gamut boundary descriptor;

customizing the gamut mapping algorithm based on the gamut boundary descriptor of the input device color profile and the gamut boundary descriptor of the output device color profile;

compositing the customized gamut mapping algorithm with either the input device appearance transform for transformation between input device dependent color space and an intermediate color space, or the output device appearance transform for transformation between the intermediate color space and an output device dependent color space, or both appearance transforms, and generating a composited transform; and

transforming image data from the input device dependent color space to the output device dependent color space using the composited transform,

wherein the intermediate color space is other than the input and output device dependent color spaces.

10. A method according to claim 9, further comprising the step of comparing between input and output device gamut, wherein the customizing step customizes the gamut mapping algorithm based on a viewing condition.

11. A method according to claim 9, wherein the customizing step customizes the gamut mapping algorithm based on a viewing condition.

12. A computer-readable storage medium in which is stored a program for controlling a computer, said program comprising codes for permitting the computer to perform:

an obtaining step, for obtaining input device color profile and output device color profile, the input device color profile and the output device color profile each include a gamut boundary descriptor;

a customizing step, for customizing the gamut mapping algorithm based on the gamut boundary descriptor of the input device color profile and the gamut boundary descriptor of the output device color profile;

a compositing step, for compositing the customized gamut mapping algorithm with either the input device appearance transform for transformation between input device dependent color space and an intermediate color space, or the output device appearance transform for transformation between the intermediate color space and an output color space, or both appearance transforms, and generating a composited transform; and

a transforming step, for transforming image data from the input device dependent color space to the output device dependent color space using the composited transform,

wherein the intermediate color space is other than the input and output device dependent color spaces.

13. A color management method using an input device appearance transform and an output device appearance transform together with a customizable gamut mapping algorithm, said method comprising the steps of:

customizing the gamut mapping algorithm based on information in regard to the gamut mapping;

compositing the customized gamut mapping algorithm with either the input device appearance transform for transformation between an input device dependent color space and an intermediate color space, or the output device appearance transform for transformation between the intermediate color space and an output device dependent color space, or the both appearance transforms; and

transforming image data from the input device dependent color space to the output device dependent color space,

wherein the intermediate color space is other than the input and output device dependent color spaces, wherein the gamut mapping algorithm operates in a device independent color space, and wherein the input or output device appearance transform is implemented as a color lookup table.

14. A color management method according to claim 13, wherein the gamut mapping algorithm operates in both a device independent and a viewing-condition independent color space.