Patent ID: 7477294

Claim:
A method for correcting the image data of a camera system for the inspection of colored printed products, comprising the steps of: (a) providing an observation area adapted to receive and illuminate a printed product; (b) providing a color camera adapted to generate first, second and third output signals for first, second and third separate color channels in the form of output signal vectors, said first, second and third output signals corresponding to image colors recorded; (c) aiming said color camera at said printed product in said observation area; (d) generating said first, second and third camera output signals corresponding to a recorded printed product image; (e) multiplying said first camera output signal by a first color-channel dependant correction factor and adding the result to a first correction vector to generate a first camera corrected output signal vector; (f) multiplying said second camera output signal by a second color-channel dependant correction factor and adding the result to a second correction vector to generate a second camera corrected output signal vector; (g) multiplying said third camera output signal by a third color-channel dependant correction factor and adding the result to a third correction vector to generate a third camera corrected output signal vector; (h) defining a camera corrected output signal vector matrix comprising said first, second and third camera corrected output signal vectors; (i) defining a correction matrix comprising selected correction coefficients; said selected correction coefficients being selected by an iterative approximation process and compared to a reference color table; and (j) multiplying said camera corrected output signal vector matrix with said correction matrix to generate a second corrected output signal vector.