Abstract

We propose a method for estimating radiometric response functions from observation of image noise variance, not profile of its distribution. The relationship between radiance intensity and noise vari- ance is affine, but due to the non-linearity of response functions, this affinity is not maintained in the observation domain. We use the non- affinity relationship between the observed intensity and noise variance to estimate radiometric response functions. In addition, we theoretically de- rive how the response function alters the intensity-variance relationship. Since our method uses noise variance as input, it is fundamentally robust against noise. Unlike prior approaches, our method does not require im- ages taken with different and known exposures. Real-world experiments demonstrate the effectiveness of our method.