Patent ID: 7884980

Claim:
A method for transforming light intensities measured by a sensor for a portion of a graphical image into a device-independent representation of color for the image portion, the method comprising the steps of: receiving by a processor an output signal from the sensor indicative of a light intensity for the image portion for each of a plurality of hyperspectral bandpasses, wherein the plurality of hyperspectral bandpasses define a spectrum characterized by wavelengths ranging continuously between 360 and 830 nanometers, and wherein the component beam for each hyperspectral bandpass is characterized by a substantially unique and non-overlapping selection of continuous wavelengths from the spectrum; converting each of the output signals for the plurality of hyperspectral bandpasses into a raw count digital data (RCT λ ) value; calculating by another processor a relative normalized intensity value (T λ ) for each of the plurality of hyperspectral bandpasses as a function of the RCT λ value, a white point (WP λ ) value and a black point (BP λ ) value, wherein the WP λ value is indicative of a light intensity that saturates the sensor and the BP λ value is indicative of a threshold electronic noise level of the sensor; storing the T λ value for each of the plurality of hyperspectral bandpasses as a hyperspectral trace representing a spectral power distribution; calculating bandpass delineated intermediate values (T λ S λ x λ , T λ S λ y λ , T λ S λ z λ ) for each of the plurality of hyperspectral bandpasses as a function of the T λ value, a user-selected Illuminant value (S λ ) and user-selected Observer values (x λ , y λ , and z λ ); calculating bandpass delineated sum values (ΣT λ S λ x λ , ΣT λ S λ y λ , ΣT λ S λ z λ ) for the image portion by respectively summing each of the bandpass delineated intermediate values (T λ S λ x λ , T λ S λ y λ , T λ S λ z λ ) for all of the plurality of hyperspectral bandpasses; calculating tristimulus values (X, Y, Z) for the image portion respectively as kΣT λ S λ x λ , kΣT λ S λ y λ , and kΣT λ S λ z λ , where a constant k is calculated as 100/ΣS λ y λ ; and storing the tristimulus values (X, Y, Z) for the image.