Recovering shading and reflectance from a single image
The Problem: Given an input image, decompose it into an image representing the shading of the scene and a second image representing the reflectance of every point in the scene. Finding the shading image can be thought of as re-rendering the image as if every surface shown in the image was made of the same material, such as plaster. Figure 1 shows an example image that has been decomposed into shading and reflectance images.