Color calibration and reflectance estimation

Ville Heikkinen, University of Eastern Finland

In the case of digital cameras and scanners, device dependent values describe response to incoming spectrum of light. A color calibration (or characterization of a measurement device, can be dened as a construction of transformation from device response values to corresponding values in device independent CIE color spaces. Due to limitations of CIE color coordinates, it has been discussed that a spectrum-based color calibration would provide signicant benets. As an example, in some color engineering applications it may be possible calibrate device response values to reectance spectra and then calculate arbitrary color coordinates by using this data.

Color calibration and reectance estimation process can be based on empirical modeling or on theoretical physical modeling. In physical modeling spectral characteristics of camera and light source are utilized. Usually in the case of empirical modeling, the previous characteristics are unknown and a priori calibration data is used to construct calibration/estimation transform via interpolation and regression models. The empirical approach can be motivated by the fact that the physical characterization of measurement device or light source can be laborious or it may require expensive devices.

The lectures are currently scheduled for July 30th.