Color transformation in 3D color space

Abstract

A method, system and computer readable medium for transforming three dimensional (3D) color information into a color standard is described. A 3D cube defined by eight RGB color points representing the eight vertices of the 3D cube is stored. Each of the eight points represents one of the colors: red, yellow, white, magenta, blue, black, green and cyan. In addition, each of the eight points represents the difference between the capacity of a display and the color standard. The 3D cube is divided into six tetrahedrons and the tetrahedron corresponding to an input RGB pixel is selected. A 3×3 matrix based on the vertices of the selected tetrahedron is calculated. The 3×3 matrix is then multiplied by the components of the input RGB pixel to produce an output RGB pixel conforming to the color standard.

What is claimed is:  
     
         1 . A method for transforming color information for conformance with a color standard, comprising the steps of: 
 storing a plurality of RGB color points representing each vertex of at least one three dimensional cube, wherein each of the RGB color points represents a difference between a capacity of an output device and a selected color standard;    dividing the three dimensional cube into a plurality of tetrahedrons;    determining which of the plurality of tetrahedrons corresponds to an input RGB pixel with an R, G and B component;    calculating a 3×3 matrix based on each vertex of a tetrahedron corresponding to the input RGB pixel; and    multiplying the 3×3 matrix by the components of the input RGB pixel, wherein an output RGB pixel conforming to the selected color standard is calculated.    
     
     
         2 . The method of  claim 1 , wherein the step of storing includes storing eight RGB color points representing each limit vertex of the three dimensional cube, wherein the eight RGB color points represent the following colors: red, yellow, white, magenta, blue, black, green and cyan.  
     
     
         3 . The method of  claim 2 , wherein the step of dividing includes: 
 dividing the three dimensional cube into six tetrahedrons, wherein each of the six tetrahedrons is defined by four limit vertices of the three dimensional cube.    
     
     
         4 . The method of  claim 3 , wherein the step of dividing includes six tetrahedrons defined by the following limit vertices of: 
 white, red, yellow, black;    white, yellow, green, black;    white, green, cyan, black;    white, cyan, blue, black;    white, magenta, blue, black; and    white, magenta, red, black.    
     
     
         5 . The method of  claim 4 , wherein the step of calculating includes: 
 calculating a 3×3 matrix based on each limit vertex of a tetrahedron corresponding to the input RGB pixel, wherein each coefficient of the first row of the 3×3 matrix are based on a first edge of the tetrahedron, wherein each coefficient of the second row of the 3×3 matrix are based on a second edge of the tetrahedron, wherein each coefficient of the third row of the 3×3 matrix are based on a third edge of the tetrahedron, and wherein each coefficient of the first, second and third row of the 3×3 matrix are not based on a black-to-white edge of the tetrahedron.    
     
     
         6 . The method of  claim 2 , wherein the step of multiplying includes: 
 multiplying the 3×3 matrix by the components of the input RGB pixel according to the formula:              (           x   1           y   1           z   1               x   2           y   2           z   2               x   3           y   3           z   3           )          (         R           G           B         )                       wherein x 1 , y 1 , z 1 , x 2 , y 2 , z 2 , x 3 , y 3  and z 3  are the coefficients of the 3×3 matrix and R, G and B represent the components of the input RGB pixel.    
     
     
         7 . The method of  claim 6 , wherein the step of multiplying further includes: 
 offsetting a result of the step of multiplying by the components of the input RGB pixel and by the components of the black limit vertex of the three dimensional cube.    
     
     
         8 . A computer readable medium including computer instructions for transforming color information into a standard color space, the computer instructions comprising instructions for: 
 storing a plurality of RGB color points representing each vertex of at least one three dimensional cube, wherein each of the RGB color points represents a difference between a capacity of an output device and a selected color standard;    dividing the three dimensional cube into a plurality of tetrahedrons;    determining which of the plurality of tetrahedrons corresponds to an input RGB pixel with an R, G and B component;    calculating a 3×3 matrix based on each vertex of a tetrahedron corresponding to the input RGB pixel; and    multiplying the 3×3 matrix by the components of the input RGB pixel, wherein an output RGB pixel conforming to the selected color standard is calculated.    
     
     
         9 . The computer readable medium of  claim 8 , wherein the instructions for storing include storing eight RGB color points representing each limit vertex of the three dimensional cube, wherein the eight RGB color points represent the following colors: red, yellow, white, magenta, blue, black, green and cyan.  
     
     
         10 . The computer readable medium of  claim 9 , wherein the instructions for dividing include: 
 dividing the three dimensional cube into six tetrahedrons, wherein each of the six tetrahedrons is defined by four limit vertices of the three dimensional cube.    
     
     
         11 . The computer readable medium of  claim 10 , wherein the instructions for dividing include six tetrahedrons defined by the following limit vertices of: 
 white, red, yellow, black;    white, yellow, green, black;    white, green, cyan, black;    white, cyan, blue, black;    white, magenta, blue, black; and    white, magenta, red, black.    
     
     
         12 . The computer readable medium of  claim 8 , wherein the instructions for calculating include: 
 calculating a 3×3 matrix based on each limit vertex of a tetrahedron corresponding to the input RGB pixel, wherein each coefficient of the first row of the 3×3 matrix are based on a first edge of the tetrahedron, wherein each coefficient of the second row of the 3×3 matrix are based on a second edge of the tetrahedron, wherein each coefficient of the third row of the 3×3 matrix are based on a third edge of the tetrahedron, and wherein each coefficient of the first, second and third row of the 3×3 matrix are not based on a black-to-white edge of the tetrahedron.    
     
     
         13 . The computer readable medium of  claim 9 , wherein the instructions for multiplying include: 
 multiplying the 3×3 matrix by the components of the input RGB pixel according to the formula:              (           x   1           y   1           z   1               x   2           y   2           z   2               x   3           y   3           z   3           )          (         R           G           B         )                       wherein x 1 , y 1 , z 1 , x 2 , y 2 , z 2 , x 3 , y 3  and z 3  are the coefficients of the 3×3 matrix and R, G and B represent the components of the input RGB pixel.    
     
     
         14 . The computer readable medium of  claim 13 , wherein the instructions for multiplying further include: 
 offsetting a result of the instructions for multiplying by the components of the input RGB pixel and by the components of the black limit vertex of the three dimensional cube.    
     
     
         15 . A system for transforming color information into a standard color space, comprising: 
 means for storing a plurality of RGB color points representing each vertex of at least one three dimensional cube, wherein each of the RGB color points represents a difference between a capacity of an output device and a selected color standard;    means for dividing the three dimensional cube into a plurality of tetrahedrons;    means for determining which of the six tetrahedrons corresponds to an input RGB pixel with an R, G and B component;    means for calculating a 3×3 matrix based on each vertex of a tetrahedron corresponding to the input RGB pixel; and    means for multiplying the 3×3 matrix by the components of the input RGB pixel, wherein an output RGB pixel conforming to the selected color standard is calculated.    
     
     
         16 . The system of  claim 15 , wherein the means for storing includes storing eight RGB color points representing each limit vertex of the three dimensional cube, wherein the eight RGB color points represent the following colors: red, yellow, white, magenta, blue, black, green and cyan.  
     
     
         17 . The system of  claim 16 , wherein the means for dividing includes: 
 means for dividing the three dimensional cube into six tetrahedrons, wherein each of the six tetrahedrons is defined by four limit vertices of the three dimensional cube.    
     
     
         18 . The system of  claim 17 , wherein the means for dividing includes six tetrahedrons defined by the following limit vertices of: 
 white, red, yellow, black;    white, yellow, green, black;    white, green, cyan, black;    white, cyan, blue, black;    white, magenta, blue, black; and    white, magenta, red, black.    
     
     
         19 . The system of  claim 18 , wherein the means for calculating includes: 
 means for calculating a 3×3 matrix based on each limit vertex of a tetrahedron corresponding to the input RGB pixel, wherein each coefficient of the first row of the 3×3 matrix are based on a first edge of the tetrahedron, wherein each coefficient of the second row of the 3×3 matrix are based on a second edge of the tetrahedron, wherein each coefficient of the third row of the 3×3 matrix are based on a third edge of the tetrahedron, and wherein each coefficient of the first, second and third row of the 3×3 matrix are not based on a black-to-white edge of the tetrahedron.    
     
     
         20 . The system of  claim 16 , wherein the means for multiplying includes: 
 means for multiplying the 3×3 matrix by the components of the input RGB pixel according to the formula:              (           x   1           y   1           z   1               x   2           y   2           z   2               x   3           y   3           z   3           )          (         R           G           B         )                       wherein x 1 , y 1 , z 1 , x 2 , y 2 , z 2 , x 3 , y 3  and z 3  are the coefficients of the 3×3 matrix and R, G and B represent the components of the input RGB pixel.    
     
     
         21 . A system for transforming color information into a standard color space, comprising: 
 an interface to storage for storing a plurality of RGB color points representing each vertex of at least one three dimensional cube, wherein each of the RGB color points represents a difference between a capacity of an output device and a selected color standard;    a processor configured to divide the three dimensional cube into a plurality of tetrahedrons;    a processor configured to determine which of the plurality of tetrahedrons corresponds to an input RGB pixel with an R, G and B component;    a processor configured to calculate a 3×3 matrix based on each vertex of a tetrahedron corresponding to the input RGB pixel; and    a processor configured to multiply the 3×3 matrix by the components of the input RGB pixel, wherein an output RGB pixel conforming to the selected color standard is calculated.    
     
     
         22 . The system of  claim 21 , wherein the system is implemented in the ST Microelectronics ADE 3250 integrated circuit.