1. A method of correcting deviations of measured image data of an image inspection system, in which the image data are determined by both a single measuring head and an image measuring unit by using a computer, the method comprising the following steps: measuring color spectrums of color fields by using the single measuring head; measuring the color spectrums of color fields by using the image measuring unit; creating a respective color set by extracting the measured spectral color values from the color spectrums of the single measuring head and of the image measuring unit; calculating spectrums resulting from overprinting all possible color combinations, each with 0% to 100% halftone area, for the single measuring head and the image measuring unit by using a color model and the respective color set; calculating Lab color values for the single measuring head and for the image measuring unit based on the respective resultant spectrums of the single measuring head and of the image measuring unit; determining deviations between the Lab color values of the single measuring head and of the image measuring unit for specific supporting points in a Lab color space; adding the determined deviations to the Lab color values of the image measuring unit at the specific supporting points; creating an ICC profile based on corrected Lab color values of the image measuring unit, the ICC profile thus converting any desired imprecise Lab measured values of the image measuring unit into accurate Lab color values; and correcting imprecisely measured Lab color values of the image measuring unit of the image inspection system by using the created ICC profile.