Appearance Harmonization for Single Image Shadow Removal
This addresses artifacts in photographs for image editing applications, but appears incremental as it builds on previous shadow removal methods.
The paper tackles the problem of visual inconsistency in shadow removal by proposing an automatic shadow region harmonization approach that reconstructs shadow regions using patches from non-shadowed areas, with quantitative evaluation showing it effectively improves upon state-of-the-art methods.
Shadows often create unwanted artifacts in photographs, and removing them can be very challenging. Previous shadow removal methods often produce de-shadowed regions that are visually inconsistent with the rest of the image. In this work we propose a fully automatic shadow region harmonization approach that improves the appearance compatibility of the de-shadowed region as typically produced by previous methods. It is based on a shadow-guided patch-based image synthesis approach that reconstructs the shadow region using patches sampled from non-shadowed regions. The result is then refined based on the reconstruction confidence to handle unique image patterns. Many shadow removal results and comparisons are show the effectiveness of our improvement. Quantitative evaluation on a benchmark dataset suggests that our automatic shadow harmonization approach effectively improves upon the state-of-the-art.