Inverse rendering for artistic paintings

It is difficult to apply inverse rendering to artistic paintings than photographs of real scenes because (1) shapes and shadings in paintings are physically incorrect due to artistic effects and (2) brush strokes disturb other factors. To overcome this difficulty of non-photorealistic rendering, we make some reasonable assumptions and then factorize the image into factors of shape, (color- and texture-independent) shading, object texture, and brush stroke texture. By transforming and combining these factors, we can manipulate grate paintings, such as relighting them and/or obtaining new views, and render new paintings, e.g., ones with Cézanne's shading and Renoir's brush strokes.