Restoring camera-captured distorted document images

Research paper by Changsong Liu, Yu Zhang, Baokang Wang, Xiaoqing Ding

Indexed on: 26 Nov '14Published on: 26 Nov '14Published in: International Journal on Document Analysis and Recognition (IJDAR)


This article discusses restoration of camera-captured distorted document images. Without the assistance of 3D data or model, our algorithm estimates and rectifies document warping just from 2D image based on line segmentation. Warping shape of each text line is acquired by estimating baselines’ shape and characters’ slant angles after line segmentation. In order to get fluent recovery result, thin-plate splines are exploited whose key points are determined through the result of warping estimation. Such process can effectively depict document warping and successfully restore warped document images to be flat. Comparison of OCR recognition rate between original camera-captured images and restored images shows the effectiveness of the algorithm proposed. We also demonstrate evaluation on DFKI dewarping contest dataset with some related algorithms. Besides desirable restoration result, processing speed of the whole procedure is satisfactory as well. In conclusion, it is applicable to be performed in OCR application to achieve better understanding of camera-captured document images.