Singularities and Regularities on Line Pictures via Symmetrical Trapezoids

An algorithm that decomposes a line image into singular and regular regions is presented. We define a contour trapezoid as the building block of regular regions, and postulate a maximal trapezoid set as the core of regular regions. Then, we describe an algorithm that calculates a maximal trapezoid set of a polygon and show how to use it to find a skeleton of a polygonal approximation of a contour. Experiments are explained to show the behavior of the new concept on real images as compared to previous algorithms.

[1]  Theodosios Pavlidis,et al.  Line sweep thinning algorithm for feature analysis , 1997, Proceedings of the Fourth International Conference on Document Analysis and Recognition.

[2]  Hiromichi Fujisawa,et al.  Substructure Shape Analysis for Kanji Character Recognition , 1996, SSPR.

[3]  Ching Y. Suen,et al.  Thinning Methodologies - A Comprehensive Survey , 1992, IEEE Trans. Pattern Anal. Mach. Intell..

[4]  Réjean Plamondon,et al.  Methodologies for Evaluating Thinning Algorithms for Character Recognition , 1993, Int. J. Pattern Recognit. Artif. Intell..

[5]  Toshihiro Suzuki,et al.  Structural Description of Line Images by the Cross Section Sequence Graph , 1993, Int. J. Pattern Recognit. Artif. Intell..

[6]  Theodosios Pavlidis,et al.  Global Shape Analysis by k-Syntactic Similarity , 1981, IEEE Transactions on Pattern Analysis and Machine Intelligence.