Wavelet-based Light Reconstruction from a Single Image

In this paper we propose a wavelet-based light representation. This representation is used for recovering illumination and reflectance of a scene with known geometry from a single calibrated image. Previous approaches of light estimation reconstruct either a discrete set of infinite light sources or the projection of light on the spherical harmonics basis. The first approach is more suitable for modeling sharp light effects while the second one works best for diffuse scenes. In contrast, we show that the proposed representation is suitable for both diffuse and specular scenes. We compared our technique with the two previously mentioned approaches and found it superior. In addition to illumination estimation our algorithm also estimates a Phong surface reflection. Experiments with synthetic and real scenes demonstrate the effectiveness of our method.