Removing Shadows from Images

We attempt to recover a 2D chromaticity intrinsic variation of a single RGB image which is independent of lighting, without requiring any prior knowledge about the camera. The proposed algorithm aims to learn an invariant direction for projecting from 2D color space to the greyscale intrinsic image. We notice that along this direction, the entropy in the derived invariant image is minimized. The experiments con-ducted on various inputs indicate that this method achieves intrinsic 2D chromaticity images which are free of shad-ows. In addition, we examined the idea to utilize projection pursuit instead of entropy minimization to find the desired direction. 1