Color management and proofing architecture

• US 6,603,483 B1
• Filed: 11/15/1999
• Issued: 08/05/2003
• Est. Priority Date: 11/15/1999
• Status: Expired due to Term

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Newman, Todd D.
• Primary Examiner(s): Luu, Matthew
• Assistant Examiner(s): Havan, Thu Thao
• Application Number:
  US09/440,463
• Time in Patent Office: 1,359 Days
• Field of Search: 345/589, 345/501, 345/600, 345/604, 345/601, 345/602, 345/603, 345/605, 345/606-610, 345/612, 345/611, 345/590, 345/591-599, 345/964, 382/162, 382/163, 382/164, 382/165, 382/166, 382/167, 358/2--, 358/3-3-, 358/515-527, 430/143
• US Class Current: 345/593
• CPC Class Codes: H04N 1/6058 Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut

Abstract

The generation of a color transformation sequence comprised of transform steps, wherein the color transformation sequence is for transforming color image data. At least one reference to a color profile or a gamut mapping algorithm is received, and at least one transform step is generated based on the at least one reference, wherein the at least one transform step is a profile step or a gamut-mapping step. The at least one transform step is included in the color transformation sequence.

Claims

1. A method for generating a color transformation sequence comprised of transform steps, said color transformation sequence for transforming color image data, said method comprising the steps of:

receiving a color profile list which includes at least one user-supplied reference to a color profile and receiving a gamut mapping algorithm list which includes at least one user-supplied reference to a gamut mapping algorithm, the color profile containing a color transform and the gamut mapping algorithm being accessed from the color profile or from an external source separate from the color profile;

generating transform steps based on the received user-supplied references, wherein the transform steps include a profile step based on the color transform and a gamut mapping step based on the gamut mapping algorithm; and

including the generated transform steps in the color transformation sequence.

2. A method according to claim 1, wherein the received references are provided by a user.

3. A method according to claim 2, wherein the received references include a color profile list and a gamut mapping algorithm list, wherein the color profile list has at least one reference entry for containing a color profile reference, and wherein the gamut-mapping algorithm list has at least one reference entry for containing a gamut mapping algorithm reference.

4. A method according to claim 3, wherein the step for generating the transform steps includes:

creating a transform step comprised of a profile step in the case that a first reference entry of the color profile list contains a color profile reference;

creating a transform step comprised of a gamut mapping step for each reference entry of the gamut mapping algorithm list that contains a gamut mapping algorithm reference;

creating a transform step comprised of a profile step for each color profile reference that corresponds to an abstract color profile and that is present in interim reference entries between the first and last entries of the color profile list; and

creating a transform step comprised of a profile step in the case that the last reference entry of the color profile list contains a color profile reference that corresponds to a device color profile.

5. A method according to claim 3, wherein the step for generating the transform steps includes:

creating one transform step comprised of a profile step in the case that a first reference entry of the color profile list contains a null value and a second reference entry of the color profile list contains a color profile reference,

wherein the profile step transforms the color image data from a device-independent color space to a device-dependent color space.

6. A method according to claim 3, wherein the step for generating the transform steps includes:

creating one transform step comprised of a profile step in the case that a first reference entry of the color profile list contains a color profile reference and a second reference entry of the color profile list contains a null value,

wherein the profile step transforms the color image data from a device-dependent color space to a device-independent color space.

7. A method according to claim 1, wherein the profile step includes a color appearance transformation and a bitfield, wherein the bitfield indicates how the color appearance transformation is applied to the color image data.

8. A method according to claim 1, wherein the gamut mapping step includes a pointer to a gamut mapping algorithm and includes a data block containing at least one gamut boundary descriptor for use by the gamut mapping algorithm to gamut map the color image data.

9. A method according to claim 1, wherein the received references contain a reference to a gamut mapping algorithm that utilizes an input gamut boundary description and an output gamut boundary description when the gamut mapping algorithm is applied to color image data.

17. Computer-executable process steps stored on a computer readable medium, said computer-executable process steps for generating a color transformation sequence comprised of transform steps, said color transformation sequence for transforming color image data, said computer-executable process steps comprising process steps according to any of claims 1 to 10.

18. A computer-readable medium which stores computer-executable process steps, the computer-executable process steps to generate a color transformation sequence comprised of transform steps, said color transformation sequence for transforming color image data, said computer-executable process steps comprising process steps according to any of claims 1 to 10.

19. A computing device for generating a color transformation sequence comprised of transform steps, said color transformation sequence for transforming color image data, said computing device comprising:

a program memory for storing process steps executable to generate a color transformation sequence comprised of transform steps according to any of claims 1 to 10; and

a processor for executing the process steps stored in said program memory.

23. A method according to claim 1, wherein the color profile list and the gamut mapping algorithm list are combined in a user-supplied transform list which includes a plurality of reference entries, the user-supplied transform list including at least one reference entry containing a color profile reference and including at least one reference entry containing a gamut mapping algorithm reference, and wherein the step for generating the transform steps includes:

creating a transform step comprised of a profile step in the case that a first reference entry of the transform list contains a color profile reference;

creating a transform step comprised of a gamut mapping step for each reference entry of the transform list that contains a gamut mapping algorithm reference;

creating a transform step comprised of a profile step for each color profile reference that corresponds to an abstract color profile and that is present in an interim reference entry between the first reference entry and a last reference entry of the transform list; and

creating a transform step comprised of a profile step in the case that the last reference entry of the transform list contains a color profile reference that corresponds to a device color profile.

10. A method for generating a color transformation sequence comprised of transform steps, said color transformation sequence for transforming color image data, said method comprising the steps of:

receiving a color profile list and a gamut mapping algorithm list, wherein the color profile list has at least one reference entry for containing a user-supplied color profile reference, and wherein the gamut-mapping algorithm list has at least one reference entry for containing a user-supplied gamut mapping algorithm reference, the color profile reference corresponding to a color profile containing a color transform, and the gamut mapping algorithm reference corresponding to a gamut mapping algorithm which is accessed from a color profile or from an external source separate from the color profile;

creating a transform step comprised of a profile step in the case that a first reference entry of the color profile list contains a color profile reference;

creating a transform step comprised of a gamut mapping step for each reference entry of the gamut mapping algorithm list that contains a gamut mapping algorithm reference;

creating a transform step comprised of a profile step for each color profile reference that corresponds to an abstract color profile and that is present in interim reference entries between the first and last entries of the color profile list;

creating a transform step comprised of a profile step in the case that the last reference entry of the color profile list contains a color profile reference that corresponds to a device color profile; and

including the created transform steps in the color transformation sequence.

11. A method for transforming color image data by applying a color transformation sequence comprised of transform steps to the color image data, said method comprising the steps of:

accessing the color transformation sequence;

accessing the color image data; and

sequentially processing each transform step of the color transformation sequence to transform the color image data,

wherein, in the case that the transform step being processed is a profile step, a color transformation module is accessed from a corresponding user-supplied color profile and is applied to the color image data, and

wherein, in the case that the transform step being processed is a gamut mapping step, a corresponding gamut mapping algorithm is accessed from a user-supplied color profile or from an external source separate from the color profile and is applied to the color image data.

12. A method according to claim 11, wherein the color transformation sequence and the color image data are provided by a user.

13. A method according to claim 11, wherein the corresponding gamut mapping algorithm is accessed from a color management module for application to the color image data.

14. A method according to claim 11, wherein the corresponding gamut mapping algorithm utilizes an input gamut boundary description and an output gamut boundary description for gamut mapping the color image data.

15. A method according to claim 13, wherein the corresponding gamut mapping algorithm utilizes an input gamut boundary description and an output gamut boundary description for gamut mapping the color image data.

20. Computer-executable process steps stored on a computer readable medium, said computer-executable process steps for transforming color image data by applying a color transformation sequence comprised of transform steps to the color image data, said computer-executable process steps comprising process steps according to any of claims 11 to 16.

21. A computer-readable medium which stores computer-executable process steps, the computer-executable process steps to transform color image data by applying a color transformation sequence comprised of transform steps to the color image data, said computer-executable process steps comprising process steps according to any of claims 11 to 16.

22. A computing device for transforming color image data by applying a color transformation sequence comprised of transform steps to the color image data, said computing device comprising:

a program memory for storing process steps executable to transform color image data by applying a color transformation sequence comprised of transform steps to the color image data, according to any of claims 11 to 16; and

a processor for executing the process steps stored in said program memory.

16. A method for transforming color image data by applying a color transformation sequence comprised of transform steps to the color image data, said method comprising the steps of:

accessing the color transformation sequence;

accessing the color image data; and

sequentially processing each transform step of the color transformation sequence to transform the color image data,

wherein, in the case that the transform step being processed is a profile step, a color transformation module is accessed from a corresponding user-supplied color profile and is applied to the color image data, and

wherein, in the case that the transform step being processed is a gamut mapping step, a corresponding gamut mapping algorithm is accessed from a color management module in a user-supplied color profile or in an external source separate from the color profile, and an input gamut boundary description and an output gamut boundary description are accessed and utilized by the gamut mapping algorithm for gamut mapping the color image data.