边界跟踪、区域填充及链码的应用研究
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摘要
边界跟踪与填充是图像处理的基本问题。链码间的转换是从已知一种链码获得其他链码的便捷方法。链码是获得图像几何特征的重要手段。文档图像的倾斜校正和表格识别是字符识别技术最重要的应用领域之一。
本文从边界跟踪、链码转换、区域填充、图像几何特征的计算到基于链码的表格处理软件，对链码相关的算法和链码的应用问题进行较为宽幅度的研究。本文的工作及研究成果可以归纳为：
1、分别就八近邻图像和四近邻图像给出了边界跟踪、顶点链码抽取及围线树结构的生成算法。首先通过构造像素顶点矩阵，利用像素顶点矩阵跟踪边界、抽取边界的顶点链码并生成围线树结构。其次设计了边界跟踪自动机，利用自动机的输出获得边界的顶点链码，自动机跟踪所有图像边界的同时生成围线树结构。这两种算法都是线性的，且适用于任意复杂图像区域，生成的围线树结构是一棵以围线类为节点的双向指针树。
2、研究了正方形点阵上二值图像的几种链码之间的相互转换算法。包括Freeman缝隙码与顶点链码之间的相互转换算法，四方向Freeman链码与顶点链码之间的相互转换算法和八方向Freeman链码与顶点链码之间的相互转换算法。这样只要获得一种链码就可以得到其它的链码表示，由某种链码获得的图像信息也为其他链码所共享。
3、分析研究并发展了基于Freeman链码、缝隙码和顶点链码的区域填充算法。算法包括一种基于Freeman链码的区域填充算法、一种基于缝隙码的区域填充算法、一种基于顶点链码的区域填充算法和一种新的奇偶点配对的区域填充算法。还给出了算法的复杂度分析，并与现有的填充算法进行了实验和比较，实验结果表明这些新算法的速度优于现有算法，特别对多连通或整幅图像填充时，由于不对区域内部孔洞填充，算法运行速度有很大提高。
4、利用区域边界的顶点链码表示，给出了计算边界点坐标和边界上任意两点之间的欧氏距离的坐标标定自动机，还给出了计算图像几何矩和图像Euler数的算法。
5、给出了一种表格文档图像的倾斜校正和表格单元格的实时识别算法，在图像倾斜校正和表格单元格识别算法的基础上，给出了一个基于图像的填表系统的设计与实现方法。
Boundary tracing and region filling are basic problems in digital image processing. Transforming chain code from one to another is convenient by transformation algorithms. It's the important method to obtain geometric characteristic of image by chain code. The slant correction and form recognition of document image are the most important applications in the field of Optical Character Recognition.
Research in this paper includes boundary tracing, transformation algorithms among chain code, region filling algorithm, obtaining geometric characteristic of image and form processing software based on chain code, algorithm and application of chain code are researched widely. The achievements are listed below:
1. Algorithms are proposed for tracing boundary and extracting vertex chain code and obtaining the tree structure of contours from 8-adjacent and 4-adjacent images. There are two algorithms in all. Firstly, trace region boundary and obtains chain code to construct tree structure of contours through a pixel vertex matrix. Secondly, designed automatic tracing machine to obtain vertex chain code and tree structure of contours at the same time of tracing the boundary of the image. Both the algorithms are linear and can be applied to arbitrary complicated image region.
2. This paper researches several transformation algorithms among different chain codes of binary image on square lattice. These algorithms are as follows: transformation algorithms of Freeman crack code and VCC, transformation algorithms of 4-direction and VCC, transformation algorithms of 8-direction and VCC. Once one kind of chain code of an image is obtained, the image information can be shared by other chain codes.
3. Region filling algorithms based on chain code are analyzed and improved, including the region filling algorithms based on Freeman chain code, crack code, vertex chain code and a new parity matching algorithm. Finally, complexity analysis of each proposed algorithms are given. Experiments indicate that compared with the existing ones, these new algorithms work better. They work much better than the current methods especially in the case of multi-connected region or the whole image, because the proposed algorithms don't fill the holes in the region.
4. In the paper, a coordinate labeling automata and an algorithm computing geometric moment and Euler number of image using vertex chain code are proposed.
本文从边界跟踪、链码转换、区域填充、图像几何特征的计算到基于链码的表格处理软件，对链码相关的算法和链码的应用问题进行较为宽幅度的研究。本文的工作及研究成果可以归纳为：
1、分别就八近邻图像和四近邻图像给出了边界跟踪、顶点链码抽取及围线树结构的生成算法。首先通过构造像素顶点矩阵，利用像素顶点矩阵跟踪边界、抽取边界的顶点链码并生成围线树结构。其次设计了边界跟踪自动机，利用自动机的输出获得边界的顶点链码，自动机跟踪所有图像边界的同时生成围线树结构。这两种算法都是线性的，且适用于任意复杂图像区域，生成的围线树结构是一棵以围线类为节点的双向指针树。
2、研究了正方形点阵上二值图像的几种链码之间的相互转换算法。包括Freeman缝隙码与顶点链码之间的相互转换算法，四方向Freeman链码与顶点链码之间的相互转换算法和八方向Freeman链码与顶点链码之间的相互转换算法。这样只要获得一种链码就可以得到其它的链码表示，由某种链码获得的图像信息也为其他链码所共享。
3、分析研究并发展了基于Freeman链码、缝隙码和顶点链码的区域填充算法。算法包括一种基于Freeman链码的区域填充算法、一种基于缝隙码的区域填充算法、一种基于顶点链码的区域填充算法和一种新的奇偶点配对的区域填充算法。还给出了算法的复杂度分析，并与现有的填充算法进行了实验和比较，实验结果表明这些新算法的速度优于现有算法，特别对多连通或整幅图像填充时，由于不对区域内部孔洞填充，算法运行速度有很大提高。
4、利用区域边界的顶点链码表示，给出了计算边界点坐标和边界上任意两点之间的欧氏距离的坐标标定自动机，还给出了计算图像几何矩和图像Euler数的算法。
5、给出了一种表格文档图像的倾斜校正和表格单元格的实时识别算法，在图像倾斜校正和表格单元格识别算法的基础上，给出了一个基于图像的填表系统的设计与实现方法。
Boundary tracing and region filling are basic problems in digital image processing. Transforming chain code from one to another is convenient by transformation algorithms. It's the important method to obtain geometric characteristic of image by chain code. The slant correction and form recognition of document image are the most important applications in the field of Optical Character Recognition.
Research in this paper includes boundary tracing, transformation algorithms among chain code, region filling algorithm, obtaining geometric characteristic of image and form processing software based on chain code, algorithm and application of chain code are researched widely. The achievements are listed below:
1. Algorithms are proposed for tracing boundary and extracting vertex chain code and obtaining the tree structure of contours from 8-adjacent and 4-adjacent images. There are two algorithms in all. Firstly, trace region boundary and obtains chain code to construct tree structure of contours through a pixel vertex matrix. Secondly, designed automatic tracing machine to obtain vertex chain code and tree structure of contours at the same time of tracing the boundary of the image. Both the algorithms are linear and can be applied to arbitrary complicated image region.
2. This paper researches several transformation algorithms among different chain codes of binary image on square lattice. These algorithms are as follows: transformation algorithms of Freeman crack code and VCC, transformation algorithms of 4-direction and VCC, transformation algorithms of 8-direction and VCC. Once one kind of chain code of an image is obtained, the image information can be shared by other chain codes.
3. Region filling algorithms based on chain code are analyzed and improved, including the region filling algorithms based on Freeman chain code, crack code, vertex chain code and a new parity matching algorithm. Finally, complexity analysis of each proposed algorithms are given. Experiments indicate that compared with the existing ones, these new algorithms work better. They work much better than the current methods especially in the case of multi-connected region or the whole image, because the proposed algorithms don't fill the holes in the region.
4. In the paper, a coordinate labeling automata and an algorithm computing geometric moment and Euler number of image using vertex chain code are proposed.
引文
[1] Belaid Y, Belaid A, Turolla E. Item searching in forms: application to French tax form. In: Proceedings of the 3rd International Conference on Document Analysis and Recognition. Washington D. C.: IEEE Computer Press, 1995, 744—747.
[2] Bribiesca E. A Chain Code for Representing 3D Curves, Pattern Recognition, 2000, 33(5):755—765.
[3] Bribiesca E. Guzman A. How to describe pure form and how to measure differences in shapes using shape numbers. Pattern Recognition, 1980, 12(1): 101 — 112.
[4] Bribiesca E. A new chain code [J]. Pattern Recognition. 1999, 32: 235—251.
[5] Bribiesca E. A chain code for representing 3D curves [J]. Pattern Recognition, 1999, 33(5): 755—765.
[6] Z. Cai. Restoration of binary images using contour direction chain codes description, CVGIP 1988,41:101 — 106.
[7] Fu Chang, Chun-Jen Chen, Chi-Jen Lu. A linear-time component-labeling algorithm using contour tracing technique[J]. Computer Vision and Image Understanding, 2004, 93(2): 206—220.
[8] Indranil Chakravarty. A Single-Pass Chain Generating Algorithm for Region Boundaries, Computer Graphics and Image Processing 1981, 15:182-193.
[9] Chung K H, Hui P M, Gu G Q. Two-dimensional traffic flow problems with faulty traffic lights. Phys Rev, 1995, E51 (1): 772—774.
[10] L.W. Chang, K. L. Leu. A fast algorithm for the restoration of images based on chain codes description and its application, CVGIP 1990, 50:296—307.
[11] Jiun-Lin Chen, Hsi-Jian Lee, An Efficient Algorithm for Form Structure Extraction Using Strip Projection, Pattern Recognition, Vol.31, No. 9, 1998, pp. 1353-1368.
[12] Louis R. Chow, H. C. Liu, S. Y. Hsu, D. W. Wu. A new dynamic approach for finding the contour of bi-level images[J]. Computer Vision, Graphics, and Image Processing, 1994, 56(6): 507—509.
[13] Carlos A. Cabrelli, Ursula M. Molter. Automatic representation of binary images[J]. IEEE Trans. On Pattern Anal. Machine Intell., 1990, PAMI-12(12): 1190—1196.
[14] Y-K. Chen, J-F. Wang. A decument skew dectection method. Pattern Recognition, 2000, 33: 195—208.
[15] M Dai,P Baylou, M Najim. An Efficient Algorithm for Computation of Shape Moments from Run-Length Codes or Chain Codes[J]. Pattern Recognition 1992,25(10): 1119—1128.
[16] Charles R. Dyer, Azriel Rosenfeld, Hanan Samet. Region representation: Boundary Codes from quadtree[J]. Communications of the ACM, 1980, 23:171-179.
[17] Dyer C R. Computing the Euler number of an image from its quadtree. Computer Graphics and Image Processing, 1980, 13(3) : 270—276.
[18] R. Fan, L. Lam, and C. Y. Suen. Processing of date information on cheques. In Proc. 5th International Workshop on Frontiers of Handwriting Recognition (IWFHR), pp.207-212, Colchester-U.K, September 1996.
[19] Fan K C, Lu J M, Wang J Y. A feature point approach to the segmentation of form document. In: Proceedings of the 3rd International Conference on Document Analysis and Recognition. Washington D. C. : IEEE Computer Press, 1995, 623—626.
[20] Fujisawa H, Nakano Y, Kurino K. Segmentation methods for character recognition: from segmentation to document structure analysis. Proceedings of the IEEE, 1992, 80(7) : 1079-1092.
[21] Freeman H. On the Encoding of Arbitrary Geometric Configuration [J]. IRE Trans, 1961, EC-10 (2): 260-268.
[22] Freeman H. Techniques for the digital computer analysis of chain-encoded arbitrary plane curves [J]. Proc Natl Elect Conf, 1961, 17 : 421-432.
[23] Freeman H. A technique for the classification and recognition of geometric patterns [A]. Proc 3rd International Congress on Cybernetics [C]. Paris: Gauthier-Villars, 1961 : 348—368.
[24] Freeman H. Computer processing of line-drawing images [J]. Computing Surveys, 1974, 6(1) : 57—97.
[25] N. Gorski, V. Anisimov, E. Augustin, O. Baret and S. Maximov. Industrial bank check processing: the A2iA CheckReaderTM, International Journal on Document Analysis and Recognition, 3:196— 206, 2001.
[26] Garris M D. Correlated run length algorithm(CURL) for detecting form structure within digitized documents. In: Proceedings of the 3rd Annual Sysmposium of Document Analysis and Information Retrieval. Washington D. C.: IEEE Computer Press, 1994, 413—424.
[27] M. A.Hatamian. Real-time two Dimensional Moment Generating Algorithm and its Single Chip Implementation. IEEE Trans, ASSSP, 1986, 34(3): 546—553.
[28] Hinds S C, Fisher J L, Amato D P D'. A document skew detection method using run-length encoding and the Hough transform[A]. In: Proceedings of the 10th International Conference on Pattern Recognition[C], Atlantic City, NJ, USA, 1990: 464—468.
[29] H. P. Hiriyannaiah. Moments Estimation in Radon Space. Pattern Recognition Letters 15, pp.227-234, 1994.
[30] Illingworth J. Kittler J. A survey of the hough transform. Computer Vision, Graphics and Image Processing, 1988, 44(1): 87—116.
[31] Ishitani Y. Document skew detection based on local region complexity[A]. In:Processing of 2nd International Conference on Document Analysis and Recognition[C], Tsukuba Science City, Japan, 1993, 49—52.
[32] X. Y. jiang, H. Bunke. simple and Fast Computation of Moments. Pattern Recognition. 1991, 24(10):801—806.
[33] Seong-Dae Kim, Jeong-Hwan Lee, Jae-Kyoon Kim. A new chain-coding algorithm for binary images using run-length codes[J]. Computer Vision, Graphics, and Image Processing, 1988, 41: 114-128.
[34] SEONG-DAE KIM, JEONG-HWAN LEE, JAE-KYOON KIM. A New Chain-Coding for Binary Images Using Run-Length Codes, Computer Vision, Graphics and Image Processing, 1988,41:114—128.
[35] Lawrence O'Gorman. The document spectrum for page layout analysis[J]. IEEE Transactions on PAMI, 1993, 15(11): 1162—1173.
[36] Liu Wenyin, Dov Dori. From raster to vectors: extracting visual information from line drawing. Pattern Analysis and Application. 1999, 2(1): 11-21.
[37] G. S. Lehal, R. Dhir. A range free skew detection technique for digitized Gurmukhi script documents. 1999 IEEE International Conference on Document Analysis and Recognition, 1999, Pages: 147— 152.
[38] Jinhui Liu, Xiaoqing Ding, Youshou Wu, Description and Recognition of Form and Automated Form Data Entry. In: Proceedings of 3rd International Conference on Docnument Analysis and Recognition, Washington D. C. :IEEE Computer Press, 1995, pp. 579—582.
[39] N. Liolios, N. Fakotakis, G. kokkinakis. Improved document skew detection based on text Line connected-component clustering. 2001 IEEE International Conference on Image Processing, 2001, Vol(1): 1098-1101.
[40] B C Li. A New computation of Geometric Moments[J], Pattern Recognition 1993, 26(1): 109—113.
[41] Bing-Cheng Li, Jun Shen. Fast Computation of Moment Invariats. Pattern Recognition, 1991, 24(10): 807—813.
[42] Yue Lu, Chew Lim Tan. A nearest-neighbor chain based approach to skew estimation in document images. Pattern Recognition Letters, 2003, 24: 2315-2323.
[43] DS Le, G R Thoma, H Wechsler. Automated page orientation and skew angle detection for binary document images[J]. Pattern Recognition, 1994, 27(10): 1325-1344.
[44] Marius C. Codrea. Note: An algorithm for contour-based region filling. Computers & graphics. 2005 29:441—450.
[45] R. D. Merrill. Represention of contours and regions for efficient computer search[J]. Communications of the ACM, 1990, 16(2): 69—82.
[46] S. Messelodi, C.M. Modena. Automatic identification and skew estimation of text lines in real scene images. Pattern Recognition, 32(1999)791-810.
[47] Daisuke Nishiwaki, Masato Hayashi, Atsushi Sato. Robust Frame Extraction and Removal for Processing Form Documents, Graphics Recognition. Algorithms and Applications: 4th International Workshop, GREC 2002, LNCS 2390, pp. 36-45, 2002.
[48] T. Pavlidis. Filling algorithm s for raster graphics. Comput. Graphics Image Process, 1979,10:126—141.
[49] Theo Pavlidis. Filling algorithms for raster graphics[J]. Computer Graphics and Image Processing, 1979, 10(2) : 126—141.
[50] Pavlidis T. Algorithms for Graphics and Image Processing. Rockville, MD:Computer Sciences Press, 1982.
[51] S. C. Park, B. K. Choi. Boundry extraction algorithm for cutting area detection, Computer-Aided Design 2001, 33:571—579.
[52] W. Philips, A New Algorithm for Moment Computation. Pattern Recognition, vol.26, No. 11, pp. 1619-1621, 1993.
[53] W Pstl. Detection of linear oblique structure and skew scan in digitized documents[A]. In: Proceedings of the 8th International Conference on Pattern Recognition[C], Pairs, France, 1986. 687—689.
[54] Rosenfeld A, Kak A C. Digital Picture Processing. Academic Press, 1976, 349-350.
[55] Roger L. T. Cederber. Chain-link coding and segmentation for raster scan devices[J]. Computer Graphics and Image Processing, 1979, 10: 224-234.
[56] Rosenfeld A. Adjacency in digital picture. Information and control. 1974,26:24-33.
[57] A. Rosenfeld. Algorithms for Image/Vector Confersion [J]. Computer Graphics, 1978, 12: 135—139.
[58] Ren Mingwu, Yang Jinyu, Sun Han. Tracing boundary contours in a binary image. Image and Vision Computing, 2002, 20:125—131.
[59] Mingwu Ren, Wangkou Yang, Jingyu Yang. A new and fast contour-filling algorithm, Pattern Recognition, 2005, 38:2564 — 2577.
[60] SATOSHI SUZUKI, KEIICHI ABE. Topological Structural Analysis of Digitized Binary Images by Border Following. COMPUTER VISION, GRAPHICS, AND IMAGE PROCESSING 1985, 30, 32-46.
[61] Hanan Samet. Region representation: quadtrees from Boundary codes[J]. Communications of the ACM, 1980, 23: 163—170.
[62] Sonka M, Hlavac V, Boyle R. Image Processing, Analysis, and Machine Vision. 2nd edition, Thomson Learning, 1999, 256—259.
[63] T. Steinherz, N. Intrator, E. Rivlin. Skew detection via principal components analysis. 1999 IEEE International Conference on Document Analysis and Recognition, 1999, Pages: 153—156.
[64] Irwin Sobel. Neighbourhood coding of binary images for fast contour following and general binary array processing[J]. Computer Graphics, and Image Processing, 1978, 8: 127-135.
[65] F. Y. Shih, W. T. Wong. An improved fast algorithm for the restoration of images based on chain codes description, CVGIP 1994, 56:348-351.
[66] G. Y. TANG. A Discrete Version of Green's Theorem[J], IEEE Transactions on Pattern Analysis and Machine Intelligence, 1982, 4(3): 242—250.
[67] Gregory Y. Tang. Region Filling with the Use of the Discrete Green Theorem[J]. Computer Vision, Graphics, and Image Processing, 1988, 42: 297-305.
[68] TAO Ren-ji, CHEN Shi-hua. Input-Trees of Finite Automata and Application to Cryptanalysis[J]. Computer Science and Technology, 2000, 15(4): 305—325.
[69] Yao-Hong Tsai and Kuo-Liang Chung. Region-filling algorithm on bincode-based contour and its implementation, Computers & Graphics 24 (2000) 529—537.
[70] T. Watanabe, Q. Luo. A multiplayer recognition method for understanding table-form documents. 1996, Int, Journal of imaging Systems and Technology, Vol. 7. pp. 279—288.
[71] Wolberg G. Digital Image Warping[M]. Los Alamitos California: IEEE Computer Society Press, 1990. 201—209.
[72] Wang D, Srihari S N. Analysis of form images. In: Proceedings of the 1st International Conference on Document Analysis and Recognition. AFCET-IRISA/INRIA, Washington D. C.: IEEE Computer Press, 1991, 181 — 191.
[73] XU Yan-bing, GU Guo-qing. Method to generate vertex chain code and the calculation of geometric quantities [J], Journal of Shanghai University, 2001, 5: 144—146.
[74] L. Yang and F. Albregtsen. Fast and Exact Computation of Cartesian Geometric Moments Using Discrete Green's Theorem. Pattern Recognition, vol. 29, No. 7, pp. 1061-1073, 1996.
[75] H Yan. Skew correction of document images using interline cross-correlation[J]. Computer Vision Graphics Image Process Graphical Models and Image Process, 1993, 55(6):538—543.
[76] Yu B., Jam A. K. A generic system for form dropout. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1996, 18(11):1127— 1131.
[77] Yuan J, Suen C Y. An Optimal O(n) Algorithm for Identifying Line Segments form a Sequence of Chain Codes. Pattern Recognition, 1995, 28(5): 635-645.
[78] J. Yuan, L. Xu, and C.Y. Suen, Form Items Extraction By Model Matching, Proc. ICDAR'91, pp. 210-218, 1991.
[79] R. Zanibbi, D. Blostein and J. R. Cordy. A Survey of Table Recognition: Models, Observations, Transformations and Inferences, International Journal on Document Analysis and Recognition 7,1 (March 2004), pp. 1～16.
[80] Zingaretti P, GasparroniM, VecciL. Fast chain coding of region boundaries. IEEE rrans Pattern Analysis and Machine Intelligence, 1998, 20(4): 407～414.
[81] M. F. Zakaria, L. J. Vroomen, P. J. A. Zsonbor-Murray, M. Kessel. Fast Algorithm for Computation of Moment Invariants. Pattern Recognition. 1987, 20(7): 639～643.
[82] Zakaria M F, Vroomen L J, Zsombor-Murray P L A, et al. Fast algorithm for the computation of moment invariants[J]. Pattern Recognition, 1987, 20(6): 639～643.
[83] 鲍丰．弱可逆有限自动机的化合与分解[J]．中国科学：A辑，1995，23 (7)：759～765．
[84] 鲍璐，钱荣松，张根度．基于有限状态机的一致性测试例自动生成方法[J]．计算机研究与发展，1996，33(3)：217～222．
[85] 曹锋，邓培民，易忠．弱可逆有限自动机的分解[J]．计算机学报，2005，28(9)：1501～1507．
[86] 陈优广，张薇，顾国庆．矩形点阵上链码的转换算法，小型微型计算机系统，2005年12月，26(12)，2190～2193．
[87] 顾国庆，许彦冰．数字图像区域标定的方法[J]，上海理工大学学报，2001，23(4)：295～299．
[88] 顾国庆，张薇．《一种得到高压缩性能的图像存储格式的方法》，发明专利，授权号：03116519．2．
[89] 顾国庆, Statistical Properties of the Additive Automaton Networks, Inter. J. Mod, Phy. 8 18 (17-19)(2004): 2463～2468.
[90] 顾国庆，匡运娟，张薇。《一种新型的奇偶配对填充算法》，发明专利，受理号：200610024852．ⅹ．
[91] 顾国庆，范炳全，许伯铭。交通系统的元胞自动机模型，系统工程理论方法应用 Vol．4(1995)12～17。
[92] 顾国庆，许伯铭，汪秉宏等．随机交通灯的二维元胞自动机交通模型．应用数学和力学，1998，19(9)：753～758．
[93] 瞿洋，杨利平，“Hough变换OCR图象倾斜矫正方法”，中国图象图形学报，2001年，第6卷(A版)，第2期，178-181页．
[94] 李华，朱光喜，朱耀庭．一种利用方向链码重建二值图像的新方法，中国图象图形学报，2000，5(6)：474～478．
[95] 李小平，任江兴，杨德刚。车牌识别系统中若干问题的探讨．北京理工大学学报，Vol．21，No．1 Feb．2001。
[96] 李国强，张薇，顾国庆．顶点链编码和区域面积的计算方法．上海理工大学学报，2003，25(3)：267～270．
[97] 李星原，高文．一种鲁棒性的结构未知表格分析方法．软件学报，1999，10(11)：1216～1224．
[98] 林应强，吴立德．区域围线追踪算法的改进，模式识别与人工智能，1994，7(3)：215～226．
[99] 刘文，刘永红，何友全．一种邮政编码自动识别系统．西南交通大学学 报，Vol．38，No．1 Feb．2003．
[100] 陆宗琪．图像处理领域轮廓跟踪及应用．中国计算机用户，1994，10：49～54．
[101] 任明武，杨静宇，孙涵．一种新的基于链码描述的轮廓填充方法，中国图象图形学报，2001，6(4)：348～352．
[102] 石秀，施泽生．FCC到VCC的转化[J]．小型微型计算机系统，2001，22(11)：1326～1330．
[103] 陶仁骥，陈世华．一种有限自动机公开钥密码体制和数字签名．计算机学报，1985(8)：401～409．
[104] 陶仁骥．自动机引论[M]．北京：科学出版社，1986年．
[105] 王涤琼，张薇，顾国庆．用顶点链编码计算图像区域的密集度和体态比，华东师范大学学报(自然科学版)，2005年3月，No．1，59～62．
[106] 王钲旋，李文辉，庞云阶．线性四元树表示的二值图像的围线追踪和Euler数的计算．计算机学报，1998，21(3)：223～228．
[107] 吴立德，林应强．基于边过程的围线追踪与围线的树结构，计算机学报，1996，19(6)：457～465．
[108] 叶晨洲．车辆牌照字符识别系统．计算机系统应用，1999，Vol．5，pp．10～13．
[109] 曾湘宁，张忻中，沈兰生．印刷表格文本分析识别系统的研究．Journal of Chinese Information Processing，1997，vol．11，No．4，33～41．
[110] 张圣希，张薇，李国强，顾国庆．利用顶点链编码探测表格的斜率，华东师范大学，2004，No．3，54-58．
[111] 张薇，陈优广，顾国庆．顶点链编码和顶点欧氏距离的计算[J]．华东师范大学学报(自然科学版)，2005，2：33～38．
[112] 章毓晋．图像分割(M)．北京：科学出版社，2001，19～75．
[113] 郑冶枫，刘长松，丁晓青，潘世言．基于有向单连通链的表格框线检测算法．软件学报，2002，13(4)：790～796．
[114] 尚振宏，刘明业．运用Freeman准则的直线检测算法．计算机辅助设计与图形学学报，2005，17(1)：49～53．
[2] Bribiesca E. A Chain Code for Representing 3D Curves, Pattern Recognition, 2000, 33(5):755—765.
[3] Bribiesca E. Guzman A. How to describe pure form and how to measure differences in shapes using shape numbers. Pattern Recognition, 1980, 12(1): 101 — 112.
[4] Bribiesca E. A new chain code [J]. Pattern Recognition. 1999, 32: 235—251.
[5] Bribiesca E. A chain code for representing 3D curves [J]. Pattern Recognition, 1999, 33(5): 755—765.
[6] Z. Cai. Restoration of binary images using contour direction chain codes description, CVGIP 1988,41:101 — 106.
[7] Fu Chang, Chun-Jen Chen, Chi-Jen Lu. A linear-time component-labeling algorithm using contour tracing technique[J]. Computer Vision and Image Understanding, 2004, 93(2): 206—220.
[8] Indranil Chakravarty. A Single-Pass Chain Generating Algorithm for Region Boundaries, Computer Graphics and Image Processing 1981, 15:182-193.
[9] Chung K H, Hui P M, Gu G Q. Two-dimensional traffic flow problems with faulty traffic lights. Phys Rev, 1995, E51 (1): 772—774.
[10] L.W. Chang, K. L. Leu. A fast algorithm for the restoration of images based on chain codes description and its application, CVGIP 1990, 50:296—307.
[11] Jiun-Lin Chen, Hsi-Jian Lee, An Efficient Algorithm for Form Structure Extraction Using Strip Projection, Pattern Recognition, Vol.31, No. 9, 1998, pp. 1353-1368.
[12] Louis R. Chow, H. C. Liu, S. Y. Hsu, D. W. Wu. A new dynamic approach for finding the contour of bi-level images[J]. Computer Vision, Graphics, and Image Processing, 1994, 56(6): 507—509.
[13] Carlos A. Cabrelli, Ursula M. Molter. Automatic representation of binary images[J]. IEEE Trans. On Pattern Anal. Machine Intell., 1990, PAMI-12(12): 1190—1196.
[14] Y-K. Chen, J-F. Wang. A decument skew dectection method. Pattern Recognition, 2000, 33: 195—208.
[15] M Dai,P Baylou, M Najim. An Efficient Algorithm for Computation of Shape Moments from Run-Length Codes or Chain Codes[J]. Pattern Recognition 1992,25(10): 1119—1128.
[16] Charles R. Dyer, Azriel Rosenfeld, Hanan Samet. Region representation: Boundary Codes from quadtree[J]. Communications of the ACM, 1980, 23:171-179.
[17] Dyer C R. Computing the Euler number of an image from its quadtree. Computer Graphics and Image Processing, 1980, 13(3) : 270—276.
[18] R. Fan, L. Lam, and C. Y. Suen. Processing of date information on cheques. In Proc. 5th International Workshop on Frontiers of Handwriting Recognition (IWFHR), pp.207-212, Colchester-U.K, September 1996.
[19] Fan K C, Lu J M, Wang J Y. A feature point approach to the segmentation of form document. In: Proceedings of the 3rd International Conference on Document Analysis and Recognition. Washington D. C. : IEEE Computer Press, 1995, 623—626.
[20] Fujisawa H, Nakano Y, Kurino K. Segmentation methods for character recognition: from segmentation to document structure analysis. Proceedings of the IEEE, 1992, 80(7) : 1079-1092.
[21] Freeman H. On the Encoding of Arbitrary Geometric Configuration [J]. IRE Trans, 1961, EC-10 (2): 260-268.
[22] Freeman H. Techniques for the digital computer analysis of chain-encoded arbitrary plane curves [J]. Proc Natl Elect Conf, 1961, 17 : 421-432.
[23] Freeman H. A technique for the classification and recognition of geometric patterns [A]. Proc 3rd International Congress on Cybernetics [C]. Paris: Gauthier-Villars, 1961 : 348—368.
[24] Freeman H. Computer processing of line-drawing images [J]. Computing Surveys, 1974, 6(1) : 57—97.
[25] N. Gorski, V. Anisimov, E. Augustin, O. Baret and S. Maximov. Industrial bank check processing: the A2iA CheckReaderTM, International Journal on Document Analysis and Recognition, 3:196— 206, 2001.
[26] Garris M D. Correlated run length algorithm(CURL) for detecting form structure within digitized documents. In: Proceedings of the 3rd Annual Sysmposium of Document Analysis and Information Retrieval. Washington D. C.: IEEE Computer Press, 1994, 413—424.
[27] M. A.Hatamian. Real-time two Dimensional Moment Generating Algorithm and its Single Chip Implementation. IEEE Trans, ASSSP, 1986, 34(3): 546—553.
[28] Hinds S C, Fisher J L, Amato D P D'. A document skew detection method using run-length encoding and the Hough transform[A]. In: Proceedings of the 10th International Conference on Pattern Recognition[C], Atlantic City, NJ, USA, 1990: 464—468.
[29] H. P. Hiriyannaiah. Moments Estimation in Radon Space. Pattern Recognition Letters 15, pp.227-234, 1994.
[30] Illingworth J. Kittler J. A survey of the hough transform. Computer Vision, Graphics and Image Processing, 1988, 44(1): 87—116.
[31] Ishitani Y. Document skew detection based on local region complexity[A]. In:Processing of 2nd International Conference on Document Analysis and Recognition[C], Tsukuba Science City, Japan, 1993, 49—52.
[32] X. Y. jiang, H. Bunke. simple and Fast Computation of Moments. Pattern Recognition. 1991, 24(10):801—806.
[33] Seong-Dae Kim, Jeong-Hwan Lee, Jae-Kyoon Kim. A new chain-coding algorithm for binary images using run-length codes[J]. Computer Vision, Graphics, and Image Processing, 1988, 41: 114-128.
[34] SEONG-DAE KIM, JEONG-HWAN LEE, JAE-KYOON KIM. A New Chain-Coding for Binary Images Using Run-Length Codes, Computer Vision, Graphics and Image Processing, 1988,41:114—128.
[35] Lawrence O'Gorman. The document spectrum for page layout analysis[J]. IEEE Transactions on PAMI, 1993, 15(11): 1162—1173.
[36] Liu Wenyin, Dov Dori. From raster to vectors: extracting visual information from line drawing. Pattern Analysis and Application. 1999, 2(1): 11-21.
[37] G. S. Lehal, R. Dhir. A range free skew detection technique for digitized Gurmukhi script documents. 1999 IEEE International Conference on Document Analysis and Recognition, 1999, Pages: 147— 152.
[38] Jinhui Liu, Xiaoqing Ding, Youshou Wu, Description and Recognition of Form and Automated Form Data Entry. In: Proceedings of 3rd International Conference on Docnument Analysis and Recognition, Washington D. C. :IEEE Computer Press, 1995, pp. 579—582.
[39] N. Liolios, N. Fakotakis, G. kokkinakis. Improved document skew detection based on text Line connected-component clustering. 2001 IEEE International Conference on Image Processing, 2001, Vol(1): 1098-1101.
[40] B C Li. A New computation of Geometric Moments[J], Pattern Recognition 1993, 26(1): 109—113.
[41] Bing-Cheng Li, Jun Shen. Fast Computation of Moment Invariats. Pattern Recognition, 1991, 24(10): 807—813.
[42] Yue Lu, Chew Lim Tan. A nearest-neighbor chain based approach to skew estimation in document images. Pattern Recognition Letters, 2003, 24: 2315-2323.
[43] DS Le, G R Thoma, H Wechsler. Automated page orientation and skew angle detection for binary document images[J]. Pattern Recognition, 1994, 27(10): 1325-1344.
[44] Marius C. Codrea. Note: An algorithm for contour-based region filling. Computers & graphics. 2005 29:441—450.
[45] R. D. Merrill. Represention of contours and regions for efficient computer search[J]. Communications of the ACM, 1990, 16(2): 69—82.
[46] S. Messelodi, C.M. Modena. Automatic identification and skew estimation of text lines in real scene images. Pattern Recognition, 32(1999)791-810.
[47] Daisuke Nishiwaki, Masato Hayashi, Atsushi Sato. Robust Frame Extraction and Removal for Processing Form Documents, Graphics Recognition. Algorithms and Applications: 4th International Workshop, GREC 2002, LNCS 2390, pp. 36-45, 2002.
[48] T. Pavlidis. Filling algorithm s for raster graphics. Comput. Graphics Image Process, 1979,10:126—141.
[49] Theo Pavlidis. Filling algorithms for raster graphics[J]. Computer Graphics and Image Processing, 1979, 10(2) : 126—141.
[50] Pavlidis T. Algorithms for Graphics and Image Processing. Rockville, MD:Computer Sciences Press, 1982.
[51] S. C. Park, B. K. Choi. Boundry extraction algorithm for cutting area detection, Computer-Aided Design 2001, 33:571—579.
[52] W. Philips, A New Algorithm for Moment Computation. Pattern Recognition, vol.26, No. 11, pp. 1619-1621, 1993.
[53] W Pstl. Detection of linear oblique structure and skew scan in digitized documents[A]. In: Proceedings of the 8th International Conference on Pattern Recognition[C], Pairs, France, 1986. 687—689.
[54] Rosenfeld A, Kak A C. Digital Picture Processing. Academic Press, 1976, 349-350.
[55] Roger L. T. Cederber. Chain-link coding and segmentation for raster scan devices[J]. Computer Graphics and Image Processing, 1979, 10: 224-234.
[56] Rosenfeld A. Adjacency in digital picture. Information and control. 1974,26:24-33.
[57] A. Rosenfeld. Algorithms for Image/Vector Confersion [J]. Computer Graphics, 1978, 12: 135—139.
[58] Ren Mingwu, Yang Jinyu, Sun Han. Tracing boundary contours in a binary image. Image and Vision Computing, 2002, 20:125—131.
[59] Mingwu Ren, Wangkou Yang, Jingyu Yang. A new and fast contour-filling algorithm, Pattern Recognition, 2005, 38:2564 — 2577.
[60] SATOSHI SUZUKI, KEIICHI ABE. Topological Structural Analysis of Digitized Binary Images by Border Following. COMPUTER VISION, GRAPHICS, AND IMAGE PROCESSING 1985, 30, 32-46.
[61] Hanan Samet. Region representation: quadtrees from Boundary codes[J]. Communications of the ACM, 1980, 23: 163—170.
[62] Sonka M, Hlavac V, Boyle R. Image Processing, Analysis, and Machine Vision. 2nd edition, Thomson Learning, 1999, 256—259.
[63] T. Steinherz, N. Intrator, E. Rivlin. Skew detection via principal components analysis. 1999 IEEE International Conference on Document Analysis and Recognition, 1999, Pages: 153—156.
[64] Irwin Sobel. Neighbourhood coding of binary images for fast contour following and general binary array processing[J]. Computer Graphics, and Image Processing, 1978, 8: 127-135.
[65] F. Y. Shih, W. T. Wong. An improved fast algorithm for the restoration of images based on chain codes description, CVGIP 1994, 56:348-351.
[66] G. Y. TANG. A Discrete Version of Green's Theorem[J], IEEE Transactions on Pattern Analysis and Machine Intelligence, 1982, 4(3): 242—250.
[67] Gregory Y. Tang. Region Filling with the Use of the Discrete Green Theorem[J]. Computer Vision, Graphics, and Image Processing, 1988, 42: 297-305.
[68] TAO Ren-ji, CHEN Shi-hua. Input-Trees of Finite Automata and Application to Cryptanalysis[J]. Computer Science and Technology, 2000, 15(4): 305—325.
[69] Yao-Hong Tsai and Kuo-Liang Chung. Region-filling algorithm on bincode-based contour and its implementation, Computers & Graphics 24 (2000) 529—537.
[70] T. Watanabe, Q. Luo. A multiplayer recognition method for understanding table-form documents. 1996, Int, Journal of imaging Systems and Technology, Vol. 7. pp. 279—288.
[71] Wolberg G. Digital Image Warping[M]. Los Alamitos California: IEEE Computer Society Press, 1990. 201—209.
[72] Wang D, Srihari S N. Analysis of form images. In: Proceedings of the 1st International Conference on Document Analysis and Recognition. AFCET-IRISA/INRIA, Washington D. C.: IEEE Computer Press, 1991, 181 — 191.
[73] XU Yan-bing, GU Guo-qing. Method to generate vertex chain code and the calculation of geometric quantities [J], Journal of Shanghai University, 2001, 5: 144—146.
[74] L. Yang and F. Albregtsen. Fast and Exact Computation of Cartesian Geometric Moments Using Discrete Green's Theorem. Pattern Recognition, vol. 29, No. 7, pp. 1061-1073, 1996.
[75] H Yan. Skew correction of document images using interline cross-correlation[J]. Computer Vision Graphics Image Process Graphical Models and Image Process, 1993, 55(6):538—543.
[76] Yu B., Jam A. K. A generic system for form dropout. IEEE Transactions on Pattern Analysis and Machine Intelligence, 1996, 18(11):1127— 1131.
[77] Yuan J, Suen C Y. An Optimal O(n) Algorithm for Identifying Line Segments form a Sequence of Chain Codes. Pattern Recognition, 1995, 28(5): 635-645.
[78] J. Yuan, L. Xu, and C.Y. Suen, Form Items Extraction By Model Matching, Proc. ICDAR'91, pp. 210-218, 1991.
[79] R. Zanibbi, D. Blostein and J. R. Cordy. A Survey of Table Recognition: Models, Observations, Transformations and Inferences, International Journal on Document Analysis and Recognition 7,1 (March 2004), pp. 1～16.
[80] Zingaretti P, GasparroniM, VecciL. Fast chain coding of region boundaries. IEEE rrans Pattern Analysis and Machine Intelligence, 1998, 20(4): 407～414.
[81] M. F. Zakaria, L. J. Vroomen, P. J. A. Zsonbor-Murray, M. Kessel. Fast Algorithm for Computation of Moment Invariants. Pattern Recognition. 1987, 20(7): 639～643.
[82] Zakaria M F, Vroomen L J, Zsombor-Murray P L A, et al. Fast algorithm for the computation of moment invariants[J]. Pattern Recognition, 1987, 20(6): 639～643.
[83] 鲍丰．弱可逆有限自动机的化合与分解[J]．中国科学：A辑，1995，23 (7)：759～765．
[84] 鲍璐，钱荣松，张根度．基于有限状态机的一致性测试例自动生成方法[J]．计算机研究与发展，1996，33(3)：217～222．
[85] 曹锋，邓培民，易忠．弱可逆有限自动机的分解[J]．计算机学报，2005，28(9)：1501～1507．
[86] 陈优广，张薇，顾国庆．矩形点阵上链码的转换算法，小型微型计算机系统，2005年12月，26(12)，2190～2193．
[87] 顾国庆，许彦冰．数字图像区域标定的方法[J]，上海理工大学学报，2001，23(4)：295～299．
[88] 顾国庆，张薇．《一种得到高压缩性能的图像存储格式的方法》，发明专利，授权号：03116519．2．
[89] 顾国庆, Statistical Properties of the Additive Automaton Networks, Inter. J. Mod, Phy. 8 18 (17-19)(2004): 2463～2468.
[90] 顾国庆，匡运娟，张薇。《一种新型的奇偶配对填充算法》，发明专利，受理号：200610024852．ⅹ．
[91] 顾国庆，范炳全，许伯铭。交通系统的元胞自动机模型，系统工程理论方法应用 Vol．4(1995)12～17。
[92] 顾国庆，许伯铭，汪秉宏等．随机交通灯的二维元胞自动机交通模型．应用数学和力学，1998，19(9)：753～758．
[93] 瞿洋，杨利平，“Hough变换OCR图象倾斜矫正方法”，中国图象图形学报，2001年，第6卷(A版)，第2期，178-181页．
[94] 李华，朱光喜，朱耀庭．一种利用方向链码重建二值图像的新方法，中国图象图形学报，2000，5(6)：474～478．
[95] 李小平，任江兴，杨德刚。车牌识别系统中若干问题的探讨．北京理工大学学报，Vol．21，No．1 Feb．2001。
[96] 李国强，张薇，顾国庆．顶点链编码和区域面积的计算方法．上海理工大学学报，2003，25(3)：267～270．
[97] 李星原，高文．一种鲁棒性的结构未知表格分析方法．软件学报，1999，10(11)：1216～1224．
[98] 林应强，吴立德．区域围线追踪算法的改进，模式识别与人工智能，1994，7(3)：215～226．
[99] 刘文，刘永红，何友全．一种邮政编码自动识别系统．西南交通大学学 报，Vol．38，No．1 Feb．2003．
[100] 陆宗琪．图像处理领域轮廓跟踪及应用．中国计算机用户，1994，10：49～54．
[101] 任明武，杨静宇，孙涵．一种新的基于链码描述的轮廓填充方法，中国图象图形学报，2001，6(4)：348～352．
[102] 石秀，施泽生．FCC到VCC的转化[J]．小型微型计算机系统，2001，22(11)：1326～1330．
[103] 陶仁骥，陈世华．一种有限自动机公开钥密码体制和数字签名．计算机学报，1985(8)：401～409．
[104] 陶仁骥．自动机引论[M]．北京：科学出版社，1986年．
[105] 王涤琼，张薇，顾国庆．用顶点链编码计算图像区域的密集度和体态比，华东师范大学学报(自然科学版)，2005年3月，No．1，59～62．
[106] 王钲旋，李文辉，庞云阶．线性四元树表示的二值图像的围线追踪和Euler数的计算．计算机学报，1998，21(3)：223～228．
[107] 吴立德，林应强．基于边过程的围线追踪与围线的树结构，计算机学报，1996，19(6)：457～465．
[108] 叶晨洲．车辆牌照字符识别系统．计算机系统应用，1999，Vol．5，pp．10～13．
[109] 曾湘宁，张忻中，沈兰生．印刷表格文本分析识别系统的研究．Journal of Chinese Information Processing，1997，vol．11，No．4，33～41．
[110] 张圣希，张薇，李国强，顾国庆．利用顶点链编码探测表格的斜率，华东师范大学，2004，No．3，54-58．
[111] 张薇，陈优广，顾国庆．顶点链编码和顶点欧氏距离的计算[J]．华东师范大学学报(自然科学版)，2005，2：33～38．
[112] 章毓晋．图像分割(M)．北京：科学出版社，2001，19～75．
[113] 郑冶枫，刘长松，丁晓青，潘世言．基于有向单连通链的表格框线检测算法．软件学报，2002，13(4)：790～796．
[114] 尚振宏，刘明业．运用Freeman准则的直线检测算法．计算机辅助设计与图形学学报，2005，17(1)：49～53．