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Restoring camera-captured distorted document images

  • Changsong Liu
  • Yu Zhang
  • Baokang Wang
  • Xiaoqing Ding
Special Issue Paper

Abstract

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.

Keywords

Baseline fitting Distorted document images Line segmentation Thin-plate splines 

Notes

Acknowledgments

This work is supported by National Natural Science Foundation of China (No. 61471214), 973 National Basic Research Program of China (No. 2014CB340506). The fourth author is also supported by National Natural Science Foundation of China (61032008).

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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Changsong Liu
    • 1
  • Yu Zhang
    • 1
  • Baokang Wang
    • 1
  • Xiaoqing Ding
    • 1
  1. 1.The State Key Laboratory of Intelligent Technology and Systems, Tsinghua National Laboratory for Information Science and Technology, Department of Electronic EngineeringTsinghua UniversityBeijingChina

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