Method for performing a color space transformation

Abstract

A method for transforming a first image defined by a first multi-dimensional color space (RGB) into second image defined by a second multi-dimensional color space (CMYK). The method computes the transformation using information derived from a previous transformation of said second image into said first image. The method then minimizes the error produced while transforming the second image back into the first image. As such, an image editing system can display on a video monitor an image that is defined in one multi-dimensional color space (RGB), print using a printer that prints images using a second multi-dimensional color space (CMYK) and edit an image using any multi-dimensional color space (either RGB or CMYK) that facilitates rapid and accurate image editing.

1. For use in a method for editing color data wherein original CMYK data is converted to RGB color data and the RGB color data is edited to provide modified RGB color data, a method for converting modified RGB color data to modified CMYK color data, the method comprising:
 providing original CMYK data; and    utilizing at least a portion of the original CMYK color data for converting modified RGB color data to modified CMYK color data;    wherein said utilizing comprises constructing an RGB-to-CMYK conversion table that contains a plurality of RGB table entries, and said constructing an RGB-to-CMYK conversion table includes, 
 transforming at least a portion of the original CMYK data to RGB data;  
 locating, for at least one of the plurality of RGB table entries, candidate CMYK data, from the original CMYK data, which transforms into RGB data in proximity to the RGB table entries; and  
 associating with at least one of the plurality of RGB table entries corresponding CMYK color data, based upon the candidate CMYK data.  
   
     
     
       2. The method of  claim 1  further comprising initializing, for at least one of the RGB table entries, corresponding CMYK color data, according to a default RGB-to-CMYK transformation. 
     
     
       3. The method of  claim 2  and wherein the default RGB-to-CMYK transformation is based upon a default black generation function. 
     
     
       4. The method of  claim 1  and wherein said constructing an RGB-to-CMYK conversion table further comprises smoothing at least a portion of the corresponding CMYK data associated with a least one of the plurality of RGB table entries, by means of a smoothing filter. 
     
     
       5. A method for converting RGB color data to converted CMYK color data, the RGB color data being derived from original CMYK color data, the method comprising:
 providing original CMYK color data; and    utilizing at least a portion of the original CMYK color data for converting RGB color data to converted CMYK color data;    wherein said utilizing comprises constructing an RGB-to-CMYK conversion table that contains a plurality of RGB table entries, and said constructing an RGB-to-CMYK conversion table includes, 
 transforming at least a portion of the original CMYK data to RGB data;  
 locating, for at least one of the plurality of RGB table entries, candidate CMYK data, from the original CMYK data, which transforms into RGB data in proximity to the RGB table entries; and  
   associating with at least one of the plurality of RGB table entries corresponding CMYK color data, based upon the candidate CMYK data.    
     
     
       6. The method of  claim 5  further comprising initializing, for at least one of the
 RGB table entries, corresponding CMYK color data, according to a default RGB-to-CMYK    transformation.    
     
     
       7. The method of  claim 6  and wherein the default RGB-to-CMYK transformation is based upon a default black generation function. 
     
     
       8. The method of  claim 5  and wherein said constructing an RGB-to-CMYK conversion table further comprises smoothing at least a portion of the corresponding CMYK data associated with at least one of the plurality of RGB table entries, by means of a smoothing filter. 
     
     
       9. For use in editing color data wherein CMYK data is converted to RGB color data and the RGB color data is edited to provide modified RGB color data, a system for converting modified RGB color data to modified CMYK color data, the system comprising:
 a source of original CMYK data; and    a color converter, utilizing at least a portion of the original CMYK data for converting modified RGB color data to modified CMYK color data;    wherein said color converter includes a table constructor, constructing an RGB-to-CMYK conversion table, that contains a plurality of RGB table entries, and the table constructor includes,    a color transformer, transforming at least a portion of the original CMYK data to RGB data;    a data finder, locating, for at least one of the plurality of RGB table entries, candidate CMYK data, from the original CMYK data, which transforms under said color transformer to RGB data in proximity to the RGB table entries; and    a data processor, associating with at least one of the plurality of RGB table entries corresponding CMYK color data, based upon the candidate CMYK data.    
     
     
       10. The system of  claim 9  and further comprising a data initializer, initializing, for at least one of the RGB table entries, corresponding CMYK color data, according to a default RGB-to-CMYK transformation. 
     
     
       11. The system of  claim 10  and wherein the default RGB-to-CMYK transformation is based upon a default black generation function. 
     
     
       12. The system of  claim 9  and wherein said table constructor further comprises a
 data smoother, smoothing at least a portion of the corresponding CMYK data associated with at least one of the plurality of RGB table entries, by means of a smoothing filter.    
     
     
       13. A system for converting RGB color data to converted CMYK color data, the RGB color data being derived from original CMYK color data, the system comprising:
 a source of original CMYK color data; and    a color converter, utilizing at least a portion of the original CMYK color data for converting RGB color data to converted CMYK color data;    wherein said color converter comprises a table that contains a constructor, constructing an RGB-to-CMYK conversion table a plurality of RGB table entries, and said table constructor includes,    a color transformer, transforming at least a portion of the original CMYK data to RGB data;    a data finder, locating, for at least one of the plurality of RGB table entries, candidate CMYK data, from the original CMYK data, which transforms under said color transformer to RGB data in proximity to the RGB table entries; and    a data processor, associating with at least one of the plurality of RGB table entries corresponding CMYK color data, based upon the candidate CMYK data.    
     
     
       14. The system of  claim 13  and further comprising a data initializer, initializing, for at least one of the RGB table entries, corresponding CMYK color data, according to a default RGB-to-CMYK transformation. 
     
     
       15. The system of  claim 14  and wherein the default RGB-to-CMYK transformation is based upon a default black generation function. 
     
     
       16. The system of  claim 13  and wherein said table constructor further comprises a data smoother, smoothing at least a portion of the corresponding CMYK data associated with at least one of the plurality of RGB table entries, by means of a smoothing filter. 
     
     
       17. A method for converting second multi-dimensional color space data to converted first multi-dimensional color space data, the second multi-dimensional color space data being derived from original first multi-dimensional color space data, comprising:
   utilizing at least a portion of the original first multi-dimensional color space data for converting second multi-dimensional color space data to converted first multi-dimensional color space data,        wherein said utilizing comprises constructing a second multi-dimensional color space data-to-first multi-dimensional color space data conversion table that contains a plurality of second multi-dimensional color space data table entries, and said constructing the second multi-dimensional color space data-to-first multi-dimensional color space data conversion table includes:      transforming at least a portion of the original first multi-dimensional color space data to second multi-dimensional color space data;        locating, for at least one of the plurality of second multi-dimensional color space data table entries, candidate first multi-dimensional color space data, from the original first multi-dimensional color space data, which transforms into second multi-dimensional color space data in proximity to the second multi-dimensional color space data table entries; and        associating with at least one of the plurality of second multi-dimensional color space data table entries corresponding first multi-dimensional color space data, based upon the candidate first multi-dimensional color space data.       
     
     
       18. The method of  claim 17 , further comprising initializing, for at least one of the second multi-dimensional color space data table entries, corresponding first multi-dimensional color space data, according to a default second multi-dimensional color space data-to-first multi-dimensional color space data transformation. 
     
     
       19. The method of  claim 18 , wherein the default second multi-dimensional color space data-to-first multi-dimensional color space data transformation is based upon a default black generation function.  
     
     
       20. The method of  claim 17 , wherein said constructing the second multi-dimensional color space data-to-first multi-dimensional color space data conversion table further comprises smoothing at least a portion of the corresponding first multi-dimensional color space data associated with at least one of the plurality of second multi-dimensional color space data table entries. 
     
     
       21. The method of  claim 17  wherein the first multi-dimensional color space is CMYK. 
     
     
       22. The method of  claim 17  wherein the second multi-dimensional color space is RGB. 
     
     
       23. For use in editing color data wherein first multi-dimensional color space data is converted to second multi-dimensional color space data and the second multi-dimensional color space data is edited to provide modified second multi-dimensional color space data, a system for converting modified second multi-dimensional color space data to modified first multi-dimensional color space data, the system comprising:
   a color converter capable of utilizing at least a portion of original first multi-dimensional color space data and converting modified second multi-dimensional color space data to modified first multi-dimensional color space data,        wherein said color converter includes a table constructor capable of constructing an second multi-dimensional color space data-to-first multi-dimensional color space data conversion table that contains a plurality of second multi-dimensional color space data table entries, and the table constructor includes:      a color transformer capable of transforming at least a portion of the original first multi-dimensional color space data to second multi-dimensional color space data;        a data finder capable of locating, for at least one of the plurality of second multi-dimensional color space data table entries, candidate first multi-dimensional color space data, from the original first multi-dimensional color space data, which transforms under said color transformer to second multi-dimensional color space data in proximity to the second multi-dimensional color space data table entries; and        a data processor capable of associating with at least one of the plurality of second multi-dimensional color space data table entries corresponding first multi-dimensional color space data, based upon the candidate first multi-dimensional color space data.       
     
     
       24. The system of  claim 23 , further comprising a data initializer capable of initializing, for at least one of the second multi-dimensional color space data table entries, corresponding first multi-dimensional color space data, according to a default second multi-dimensional color space data-to-first multi-dimensional color space data transformation. 
     
     
       25. The system of  claim 24 , wherein the default second multi-dimensional color space data-to-first multi-dimensional color space data transformation is based upon a default black generation function. 
     
     
       26. The system of  claim 23 , wherein said table constructor further comprises a data smoother capable of smoothing at least a portion of the corresponding first multi-dimensional color space data associated with at least one of the plurality of second multi-dimensional color space data table entries. 
     
     
       27. The system of  claim 23 , further comprising a source of the original first multi-dimensional color space data. 
     
     
       28. The system of  claim 23  wherein the first multi-dimensional color space is CMYK. 
     
     
       29. The system of  claim 23  wherein the second multi-dimensional color space is RGB. 
     
     
       30. A system for converting second multi-dimensional color space data to converted first multi-dimensional color space data, the second multi-dimensional color space data being derived from original first multi-dimensional color space data, comprising:
   a color converter capable of utilizing at least a portion of the original first multi-dimensional color space data and converting second multi-dimensional color space data to converted first multi-dimensional color space data;        wherein said color converter comprises a table that contains a constructor capable of constructing a second multi-dimensional color space data-to-first multi-dimensional color space data conversion table that contains a plurality of second multi-dimensional color space data table entries, and said table constructor includes:      a color transformer capable of transforming at least a portion of the original first multi-dimensional color space data to second multi-dimensional color space data;        a data finder capable of locating, for at least one of the plurality of second multi-dimensional color space data table entries, candidate first multi-dimensional color space data, from the original first multi-dimensional color space data, which transforms under said color transformer to second multi-dimensional color space data in proximity to the second multi-dimensional color space data table entries; and        a data processor capable of associating with at least one of the plurality of second multi-dimensional color space data table entries corresponding first multi-dimensional color space data, based upon the candidate first multi-dimensional color space data.       
     
     
       31. The system of  claim 30 , further comprising a data initializer capable of initializing, for at least one of the second multi-dimensional color space data table entries, corresponding first multi-dimensional color space data, according to a default second multi-dimensional color space data-to-first multi-dimensional color space data transformation. 
     
     
       32. The system of  claim 31 , wherein the default second multi-dimensional color space data-to-first multi-dimensional color space data transformation is based upon a default black generation function. 
     
     
       33. The system of  claim 30 , wherein said table constructor further comprises a data smoother, smoothing at least a portion of the corresponding first multi-dimensional color space data associated with at least one of the plurality of second multi-dimensional color space data table entries. 
     
     
       34. The system of  claim 30 , further comprising a source of the original first multi-dimensional color space data. 
     
     
       35. The system of  claim 30  wherein the first multi-dimensional color space is CMYK. 
     
     
       36. The system of  claim 30  wherein the second multi-dimensional color space is RGB.