DIY absolute tele-colorimeter using a camera-projector system

Abstract

Image-based reflectance measurement setups lower costs and increase the speed of reflectance acquisition. Unfortunately, consumer camera sensors are designed to produce aesthetically pleasing images, rather than faithfully capture the colors of a scene. We present a novel approach for colorimetric camera characterization, which exploits a commonly available projector as controllable light source, and accurately relates the camera sensor response to the known reflected radiance. The characterized camera can be effectively used as a 2D tele-colorimeter, suitable for image-based reflectance measurements, spectral prefiltering and spectral up-sampling for rendering, and to improve color accuracy in HDR imaging. We demonstrate our method in the context of radiometric compensation. Coupled with a gamut-mapping technique, it allows to seamlessly project images on almost any surface, including non-flat, colored or even textured ones.