Simultaneous Camera, Light Position and Radiant Intensity Distribution Calibration

We propose a practical method for calibrating the position and the Radiant Intensity Distribution (RID) of light sources from images of Lambertian planes. In contrast with existing techniques that rely on the presence of specularities, we prove a novel geometric property relative to the brightness of Lambertian planes that allows to robustly calibrate the illuminant parameters without the detrimental effects of view-dependent reflectance and a large decrease in complexity. We further show closed form solutions for position and RID of common types of light sources. The proposed method can be seamlessly integrated within the camera calibration pipeline, and its validity against the state-of-the-art is shown both on synthetic and real data.