Camera sensitivity measurements without a spectroradiometer

Abstract

We validate a new technique for getting the channel sensitivities of color cameras which uses only a dispersing element and a single image captured by the camera itself. The measured sensitivities are compared with standard measurements using a monochromator and spectroradiometer. Results for Hitachi 3CCD HV-C20 and a Sony X711 show accurate agreement. We refine the technique by removing the effect of the light source used (a Tungsten-Halogen lamp) from the measured color signals. Without using a spectroradiometer, the color temperature of the lamp is determined using Wien's displacement law and its spectrum is estimated as a blackbody radiator. Comparison of actual images versus rendered color outputs from spectral information of red, green, blue and yellow patches in a Macbeth color checker show good color appearance match.