Imaging Techniques in Document Analysis Processes(文档分析过程中的图像技术)

Posted 2021-03-14 2008nmj

4. Imaging Techniques in Document Analysis Processes(文档分析过程中的图像技术)

Contents
Introduction. ....................................................................................... 74
Basic Image Processing Algorithms. ............................................................. 74
  Morphological Operations. ................................................................... 75
  Skeletonization. ............................................................................... 75
  Connected Component Labeling.............................................................. 76
  Run-Length Smoothing Algorithm (RLSA). ................................................ 76
  Distance Transform. ........................................................................... 76
  Hough Transform ............................................................................. 77
  Projection Profiles. ............................................................................ 77
Document Image Binarization. ................................................................... 77
  Global Thresholding Techniques. ............................................................ 79
  Local Thresholding Techniques. ............................................................. 86
  Hybrid Thresholding Techniques. ............................................................ 90
  Combining Different Binarization Techniques. .............................................. 91
  Using Training Samples....................................................................... 92
  Binarization of Color Documents. ............................................................ 94
Document Image Enhancement. .................................................................. 95
  Low Contrast and Uneven Background Illumination........................................ 95
  Bleed-Through, Shining, or Shadow-Through Effects. .......... ........... ............ .... 97
  Damaged Characters or Noisy Background. ................................................. 101
  Borders or Parts of Adjacent Page. ........................................................... 102
Document Image Normalization.................................................................. 104
  Page Orientation............................................................................... 104
  Deskew and Deslant. .......................................................................... 112
  Dewarping. .................................................................................... 123
Conclusion. ........................................................................................ 127
Cross-References. ................................................................................. 127
References. ........................................................................................ 128
  Further Reading. .............................................................................. 131