Color selection and/or matching in a color image

Abstract

A method or computer program product for color selection in a color image, including operations or instructions for selecting a base color in a base color portion of a color image; computing a perceptual color difference between the base color and a respective second color in the color image; comparing the perceptual color difference to a tolerance; and, identifying whether the color difference satisfies the tolerance.

What is claimed is: 
     
         1 . A method for color selection in a color image, the method comprising:
 selecting a base color in a base color portion of a color image;   computing a perceptual color difference between the base color and a respective second color in the color image;   comparing the perceptual color difference to a tolerance; and,   identifying whether the color difference satisfies the tolerance.   
     
     
         2 . A method according to  claim 1  wherein the identifying operation identifies the respective second color as a match to the original base color when the tolerance is satisfied. 
     
     
         3 . A method according to  claim 1  wherein the identifying operation identifies the respective second color as a match to the original base color when the tolerance is satisfied, and identifies the second color as part of the base color portion of the color image. 
     
     
         4 . A method according to  claim 1  wherein the identifying operation provides for selecting by color one or both of an object or a region in the color image. 
     
     
         5 . A method according to  claim 1  wherein the respective second color is in one of a contiguous or a non-contiguous portion of the color image. 
     
     
         6 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations are performed on a pixel-by-pixel basis. 
     
     
         7 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations includes use of a chromaticity color system. 
     
     
         8 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations includes use of a chromaticity color system including use of a common chromaticity coordinate. 
     
     
         9 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations includes use of a chromaticity color system including use of one or more of a CIE xyY or CIE xy chromaticity color space, or a projective transformation of an additive, linear-energy color system. 
     
     
         10 . A method according to  claim 1  wherein the CIE xy chromaticity is computed from the CIE XYZ additive primaries as x=X/(X+Y+Z) and y=Y/(X+Y+Z). 
     
     
         11 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations includes use of a perceptual color system. 
     
     
         12 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations includes use of a perceptual color system including one or more of a CIE L*, CIE L*a*b* and CIE L*u*v* color space. 
     
     
         13 . A method according to  claim 1  further including using a CIE xy color space and one or both of a histogram and a chromaticity diagram. 
     
     
         14 . A method according to  claim 1  further including using a CIE xy color space and one or both of a histogram and a chromaticity diagram to identify a color concentration representative of a dominant base color. 
     
     
         15 . A method according to  claim 1  further including using a CIE xyY color space and one or both of a histogram and a chromaticity diagram to identify a color concentration representative of a dominant base color; and further including one or more of segmenting or enclosing a color concentration. 
     
     
         16 . A method according to  claim 15  wherein the enclosing operation includes using one or more of a circle, an ellipse, a polygon or a non-smooth shape. 
     
     
         17 . A method according to  claim 15  wherein the enclosing operation includes adjusting a radius to set the tolerance. 
     
     
         18 . A method according to  claim 1  wherein one or more of the selecting, computing, comparing and identifying operations includes use of a one, two or three dimensional solution, the one, two or three dimensional solution including one of a CIE L*, CIE xy or a CIE L*a*b* color space. 
     
     
         19 . A method according to  claim 1  wherein the comparing operation is repeated with a second tolerance without a repetition of the selection or computing operations. 
     
     
         20 . A method according to  claim 1  wherein the comparing operation, the tolerance is adjustable and re-applicable to the color difference. 
     
     
         21 . A computer program product in a computer readable medium for use in a data processing system for executing a computer program, the computer program product comprising instructions for operating a method according to  claim 1 . 
     
     
         22 . A computer program product for color selection in a color image, the computer program product comprising:
 first instructions for a base color in a base color portion of a color image;   second instructions for computing a perceptual color difference between the base color and a respective second color in the color image;   third instructions for comparing the perceptual color difference to a tolerance; and,   fourth instructions for identifying whether the color difference satisfies the tolerance.   
     
     
         23 . A method for selecting a color in a color image, the color image having a plurality of candidate pixels, the method comprising:
 selecting a reference pixel determining an original base color in a region of a color image; computing a color difference in a pre-determined perceptual color space relative between the color value of the reference pixel and the color value of each candidate pixel in the color image;   applying a tolerance to each color difference;   setting a flag for each candidate pixel having a difference satisfying the tolerance.