Origami: Multiview Rectification of Folded Documents

Digitally unwrapping paper sheets is a crucial step for document scanning and accurate text recognition. This paper presents a method for automatically rectifying curved or folded paper sheets from a small number of images captured from different viewpoints. Unlike previous techniques that require either an expensive 3D scanner or over-simplified parametric representation of the deformations, our method only uses a few images and is based on general developable surface model that can represent diverse sets of deformation of paper sheets. By exploiting the geometric property of developable surfaces, we develop a robust rectification method based on ridge-aware 3D reconstruction of the paper sheet and `1 conformal mapping. We evaluate the proposed technique quantitatively and qualitatively using a wide variety of input documents, such as receipts, book pages and letters.