Digitally unwrapping images of paper sheets is crucial for accurate document scanning and text recognition. This paper presents a method for automatically rectifying curved or folded paper sheets from a few images captured from multiple viewpoints. Prior methods either need expensive 3D scanners or model deformable surfaces using over-simplified parametric representations. In contrast, our method uses regular images and is based on general developable surface models that can represent a wide variety of paper deformations. Our main contribution is a new robust rectification method based on ridge-aware 3D reconstruction of a paper sheet and unwrapping the reconstructed surface using properties of developable surfaces via ℓ1 conformal mapping. We present results on several examples including book pages, folded letters and shopping receipts.
@article{arxiv.1606.00166,
title = {Multiview Rectification of Folded Documents},
author = {Shaodi You and Yasuyuki Matsushita and Sudipta Sinha and Yusuke Bou and Katsushi Ikeuchi},
journal= {arXiv preprint arXiv:1606.00166},
year = {2016}
}