Planar shape recognition by directional flow-change method

Abstract A method based on directional flow-change concept is proposed in this paper for recognizing planar shapes. This method locates critical points by evaluating directional flow-changes in terms of chain code directions along the contour. An angle string can be obtained by computing the sizes of angles at the critical points and then converting them into some special angle codes. Possible shape numbers are generated by applying a set of rules to the angle string. Consequently, the task of shape recognition is transformed to the task of comparing shape numbers. Experimental results show that our method is very effective in recognizing shapes and more efficient in computation than the curve bending function (CBF) method.

[1]  M. Fischler,et al.  Perceptual organization and curve partitioning , 1987 .

[2]  Pengfei Zhu,et al.  On Critical Point Detection of Digital Shapes , 1995, IEEE Trans. Pattern Anal. Mach. Intell..

[3]  Hong Yan,et al.  A curve bend function based method to characterize contour shapes , 1997, Pattern Recognit..

[4]  Hong Yan,et al.  Effective classification of planar shapes based on curve segment properties , 1997, Pattern Recognit. Lett..

[5]  Roland T. Chin,et al.  Scale-Based Detection of Corners of Planar Curves , 1992, IEEE Trans. Pattern Anal. Mach. Intell..

[6]  Ernesto Bribiesca,et al.  How to describe pure form and how to measure differences in shapes using shape numbers , 1980, Pattern Recognit..

[7]  Naonori Ueda,et al.  Learning Visual Models from Shape Contours Using Multiscale Convex/Concave Structure Matching , 1993, IEEE Trans. Pattern Anal. Mach. Intell..

[8]  Azriel Rosenfeld,et al.  Angle Detection on Digital Curves , 1973, IEEE Transactions on Computers.

[9]  Azriel Rosenfeld,et al.  An Improved Method of Angle Detection on Digital Curves , 1975, IEEE Transactions on Computers.

[10]  B. Rosenberg,et al.  Computing Dominant Points on Simple Shapes , 1974, Int. J. Man Mach. Stud..

[11]  Carlo Arcelli,et al.  Finding contour-based abstractions of planar patterns , 1993, Pattern Recognit..

[12]  Larry S. Davis,et al.  Understanding Shape: Angles and Sides , 1977, IEEE Transactions on Computers.

[13]  B. Rosenberg.  The analysis of convex blobs , 1972, Comput. Graph. Image Process..

[14]  Hideo Ogawa.  Corner detection on digital curves based on local symmetry of the shape , 1989, Pattern Recognit..

[15]  Herbert Freeman,et al.  Computer Processing of Line-Drawing Images , 1974, CSUR.

[16]  Farzin Mokhtarian,et al.  A Theory of Multiscale, Curvature-Based Shape Representation for Planar Curves , 1992, IEEE Trans. Pattern Anal. Mach. Intell..

[17]  Roland T. Chin,et al.  On the Detection of Dominant Points on Digital Curves , 1989, IEEE Trans. Pattern Anal. Mach. Intell..