Estimation of 3D shape of warped document surface for image restoration

While scanning pages from a thick, bound book, there are two sources of distortion in the document images: 1) shade along the book ´spine´, and 2) warping of the book surface in the shade area. We propose a fast method to estimate the 3D shape of a book surface. Based on this shape, we remove the shade and correct the warping to restore the document images. The experiments show that the photometric and geometric distortions are mostly removed. The OCR tests on the original and restored document images are also presented.