Does Inverse Lighting Work Well under Unknown Response Function?

Inverse lighting is a technique for recovering the lighting environment of a scene from a single image of an object. Conventionally, inverse lighting assumes that a pixel value is proportional to radiance value, i.e. the response function of a camera is linear. Unfortunately, however, consumer cameras usually have unknown and nonlinear response functions, and therefore conventional inverse lighting does not work well for images taken by those cameras. In this study, we propose a method for simultaneously recovering the lighting environment of a scene and the response function of a camera from a single image. Through a number of experiments using synthetic images, we demonstrate that the performance of our proposed method depends on the lighting distribution, response function, and surface albedo, and address under what conditions the simultaneous recovery of the lighting environment and response function works well.