Method and system for correcting color display based upon ambient light

Claim 1

A method of color matching between a display monitor and an image-carrying substrate, comprising the steps of: a) comparing a predetermined color patch on the image-carrying substrate with a corresponding color output on the display monitor under a light condition, said predetermined color patch being specified by a first set of known values according to a first color system, said corresponding color output being generated based upon a second set of signals according to a second color system, said first set of values including CIE tri-stimulus x, y, and z values while said second set of signals including RGB signals; b) making a change in said y value which is an intensity related value of said first set of said values so that said predetermined color patch and said corresponding color output on the display monitor appear substantially identical in their color representation, said step b) further comprising: iii) converting said Y value into a L* value defining luminance by a first equation, L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100. iv) modifying said L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β); and v) converting said L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and c) generating each of said signals of said second set based upon said change in said intensity related value in said first set.

Claim 2

A method of color matching between a display monitor and an image-carrying substrate, comprising the steps of: a) comparing a predetermined color patch on the image-carrying substrate with a corresponding color output on the display monitor under a light condition, said predetermined color patch being specified by a first set of known values according to a first color system, said corresponding color output being generated based upon a second set of signals according to a second color system, said first set of values including CIE tri-stimulus x, y, and z values while said second set of signals including RGB signals; b) making a change in said y value which is an intensity related value of said first set of said values so that said predetermined color patch and said corresponding color output on the display monitor appear substantially identical in their color representation, said step b) further comprising: iii) converting said Y value into a L* value defining luminance by a first equation, L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100. iv) modifying said L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β); and v) converting said L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and c) generating each of said signals of said second set based upon said change in said intensity related value in said first set.

Claim 12

A method of correcting predetermined CIE XYZ values of a color patch into RGB values for a viewer under ambient light, comprising the steps of: a) taking a measurement of the ambient light of substantially identical chromaticity coordinates of those for the predetermined CIE XYZ; b) adjusting the RGB values based upon the measurement for a color presentation on a monitor; and c) further adjusting the RGB values until the viewer perceives that the color presentation matches the color patch, said step c) further comprising: d) determining luminous conversion coefficients α and β; i) converting the Y value into a luminance L* value according to a conversion equation L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100; ii) modifying the L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β); and iii) converting the L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and e) storing said luminous conversion coefficients α and β.

Claim 13

A method of correcting predetermined CIE XYZ values of a color patch into RGB values for a viewer under ambient light, comprising the steps of: a) taking a measurement of the ambient light of substantially identical chromaticity coordinates of those for the predetermined CIE XYZ; b) adjusting the RGB values based upon the measurement for a color presentation on a monitor; and c) further adjusting the RGB values until the viewer perceives that the color presentation matches the color patch, said step c) further comprising: d) determining luminous conversion coefficients α and β; i) converting the Y value into a luminance L* value according to a conversion equation L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100; ii) modifying the L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β); and iii) converting the L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and e) storing said luminous conversion coefficients α and β.

Claim 19

A system for color matching between a display monitor and an image-carrying substrate, comprising: a predetermined color patch on the image-carrying substrate, said predetermined color patch being specified by a first set of values including x, y and z values according to a first color system of CIE tri-stimulus under a predetermined light condition; an output device for outputting a color output corresponding to said predetermined color patch, said corresponding color output being generated based upon a second set of R, G and B signals according to a second color system of RGB; a light measuring device for taking a measurement of said light condition, a controller connected to said light measuring device for varying an intensity related value of said y value based upon said measurement so as to cause the corresponding color output from said output device appear substantially identical to said color patch, said controller further comprising a converter for converting said Y value into a L* value defining luminance by a first equation, L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100, said converter modifying said L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β), said convertor converts said L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and a signal generator connected to said controller and said output device for generating each of said signals of said second set based upon said varied intensity related value in said first set.

Claim 20

A system for color matching between a display monitor and an image-carrying substrate, comprising: a predetermined color patch on the image-carrying substrate, said predetermined color patch being specified by a first set of values including x, y and z values according to a first color system of CIE tri-stimulus under a predetermined light condition; an output device for outputting a color output corresponding to said predetermined color patch, said corresponding color output being generated based upon a second set of R, G and B signals according to a second color system of RGB; a light measuring device for taking a measurement of said light condition, a controller connected to said light measuring device for varying an intensity related value of said y value based upon said measurement so as to cause the corresponding color output from said output device appear substantially identical to said color patch, said controller further comprising a converter for converting said Y value into a L* value defining luminance by a first equation, L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100, said converter modifying said L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β), said convertor converts said L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and a signal generator connected to said controller and said output device for generating each of said signals of said second set based upon said varied intensity related value in said first set.

Claim 29

A system for converting predetermined CIE XYZ values of a color patch into RGB values of a monitor for viewing under ambient light, comprising: a light measuring device for taking a measurement of the ambient light of substantially identical chromaticity coordinates of those for the predetermined CIE XYZ; a first adjustor for adjusting the RGB values based upon the measurement for a color presentation on said monitor, said first adjustor including: a determining device for determining luminance conversion coefficients αand β; and a memory for storing the luminance conversion coefficients α and β; said determining device converts the Y value into a luminance L* value according to a conversion equation L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100, said determining device modifying the L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β), said determining device converting the L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and a second adjustor for further adjusting the RGB values until the viewer perceives that the color presentation and the color patch are substantially identical.

Claim 30

A system for converting predetermined CIE XYZ values of a color patch into RGB values of a monitor for viewing under ambient light, comprising: a light measuring device for taking a measurement of the ambient light of substantially identical chromaticity coordinates of those for the predetermined CIE XYZ; a first adjustor for adjusting the RGB values based upon the measurement for a color presentation on said monitor, said first adjustor including: a determining device for determining luminance conversion coefficients αand β; and a memory for storing the luminance conversion coefficients α and β; said determining device converts the Y value into a luminance L* value according to a conversion equation L*=116 (Y/Y n ) 1/3 -16, Y n being defined as 100, said determining device modifying the L* value by luminance conversion coefficients α and β into L'* which is defined by α(L*-β), said determining device converting the L'* back to a modified a Y' value which is defined by Y n ((L'*+16)/116) 3 ; and a second adjustor for further adjusting the RGB values until the viewer perceives that the color presentation and the color patch are substantially identical.