Method for converting digital color images
A method for characterizing a color in terms of tristimulus values, the method includes providing a source of a color; measuring a set of spectral values for color stimulus associated with the color using a spectral measurement device controlled by a digital processing system; calculating a first set of tristimulus values from the set of spectral values; defining a set of human observer color matching functions, the set of human observer color matching functions being functions of the tristimulus values; and determining a second set of tristimulus values from the set of spectral values using set of human observer color matching functions.
1. A method for characterizing a color in terms of tristimulus values, the method comprising:
providing a source of a color;
measuring a set of spectral values for color stimulus associated with the color using a spectral measurement device controlled by a digital processing system;
calculating a first set of tristimulus values from the set of spectral values;
defining a set of human observer color matching functions, the set of human observer color matching functions being functions of the tristimulus values; and
determining a second set of tristimulus values from the set of spectral values using the defined set of human observer color matching functions.
2. The method of claim 1 , wherein the second set of tristimulus values is converted to a perceptually uniform color space.
3. The method of claim 1 , wherein the source of the color is an illumination system.
4. The method of claim 2 , wherein the source of the color is an illumination system.
5. The method of claim 1 , wherein the source of the color is a reflective material viewed in an illumination system.
6. The method of claim 2 , wherein the source of the color is a reflective material viewed in an illumination system.
7. The method of claim 1 , wherein the source of the color is an emissive display system.
8. The method of claim 2 , wherein the source of the color is an emissive display system.
9. The method of claim 1 , wherein the source of the color is a digital projection system.
10. The method of claim 2 , wherein the source of the color is a digital projection system.
11. The method of claim 1 , wherein the set of human observer color matching functions are defined according to the equation xyz C (λ)=α({right arrow over (XYZ)} S ) xyz S (λ)+(1.0−α({right arrow over (XYZ)} S )) xyz M (λ) wherein xyz M (λ) denotes human observer functions obtained using the Maxwell method of matching whites, xyz S (λ) denotes human observer functions derived from the saturation method, xyz C (λ) refers to the corrected human observer function, and α({right arrow over (XYZ)} S ) is a function of tristimulus values calculated from xyz S (λ).
12. The method of claim 1 , wherein the tristimulus values are the cone values LMS and the color matching functions are the cone responses l (λ) m (λ) s (λ).