This includes algorithm and also datasets
(1) CJV-based shading correction method is described in "src" file
(2) Real datasets
Real datasets 1-4 include ten shaded images each
(3) Artificial datasets
evenImg_ArtData1/2: simulated shading-free image realIllumImg_ArtData1/2: simulated shading field unevenImg__ArtData1/2: simulated shaded image