Apparatus and method for accurate electronic color capture and reproduction

An electronic color capture system for capturing a color image and producing an accurate color reproduction of the color image, said system comprising:

• a plurality of image sensors for capturing the image and generating a plurality of color image signals from the captured image, each image sensor having predetermined spectral sensitivities defining the spectral response of the image sensor;
• an optical section including at least one optical element for directing image light of a particular color content toward each image sensor and at least one cutoff filter in an optical path of each image sensor for filtering the color light content directed upon the respective image sensor, said optical section having spectral characteristics comprised of specific optical element characteristics and specific filter characteristics which together define the spectral response of the optical section;
• wherein the spectral responses of the optical section and the image sensors are selected so as to cascade together to provide all-positive, Gaussian system curves modeled upon red, green and blue color matching functions representative of the human visual system and derived from three monochromatic light sources, said color matching functions containing no more than three positive lobes as well as one or more negative lobes, and whereby the areas under the color matching functions (a) determined by summation of all negative lobes is minimized and (b) determined by overlap between the green and red color matching functions is minimized;
• a color correction matrix containing matrix coefficients that are selected by minimizing at least two error measuring parameters including one parameter measuring the color difference between the color image signals and the human visual system and the other parameter measuring the level of signal noise in the color image signals;
• and
• a processor for applying the color correction matrix to the color image signals produced by the image sensors, thereby producing an output color image signal exhibiting an accurate color reproduction of the color image.

A method for capturing an image and producing an accurate color reproduction of the image, said method comprising the steps of:

• providing an imaging section having predetermined spectral sensitivities defining a spectral response of the imaging section, said imaging section capturing the image and generating a plurality of color image signals from the captured image;
• providing an optical section having specific spectral characteristics which define a spectral response of the optical section, said optical section separating the image into its separate color content and directing the separate color content toward said imaging section;
• selecting the spectral responses of the optical section and the imaging section so that they cascade together to provide all-positive, symmetrical system curves modeled upon red, green and blue color matching functions representative of the human visual system and derived from three monochromatic light sources, said color matching functions containing no more than three positive lobes as well as one or more negative lobes, and whereby the areas under the color matching functions (a) determined by summation of all negative lobes is minimized and (b) determined by overlap between the green and red color matching functions is minimized;
• and
• processing the color image signals with a color correction matrix having coefficients optimized for signal-to-noise performance for producing an output color image from the color image signals exhibiting an accurate color reproduction of the color image.