Color Measurement by Imaging Spectrometry

Spectral imaging has the potential to make spatially resolved absolute color measurement possible for automatic visual inspection in industrial production applications. In this paper, a detailed description and evaluation of the calibration of such an imaging spectrograph is given. The reproducibility of the reflectance factors measured by the spectrograph is determined empirically and the measurements are compared to those of a spectrophotometer. Based on the CCD camera sensitivity, the probability that a measured color is within one CIE L*a*b* unit of the actual color is predicted theoretically. This result is verified in practice.