Camera response function recovery from different illuminations of identical subject matter

A robust method of camera response function estimation, using pictures taken by differently illuminating the same subject matter, is presented. The method solves for the response function directly using superposition constraints imposed by different combinations of two (or more) lights to illuminate the same subject matter. Previous methods of computing camera response functions typically used differing exposures of identical subject matter, leading to uniqueness problems (underconstrained due to comparametric periodicity or fractal ambiguity). The method used in this paper overcomes this problem. Finally, we compare the method of the paper to previous methods and find the new method outperforms the previous work.