We propose a classier that takes as input a shadow region and a neighboring lit
region.
For each shadow region Rs we need to identify which of its lit neighbors
Ri shares the same material with Rs. If a lit neighbor shares the same material
then it can be used to relight Rs by applying the transformation T previously
described in Section 2. Hence, we select features that describe: i) the similar-
ity between Rs and Ri, ii) the transformation dened by the pair of regions
T(Rs;Ri), and iii) the results of applying that transformation. If Rr and Ri,
have the same material, the relit shadow region c Rs and the lit region should be
similar in color and texture. We compute the following features: