Stony Brook Algorithm Repository

Shape Similarity


Input Description: Two polygonal shapes, \(P_1\) and \(P_2\).
Problem: How similar are \(P_1\) and \(P_2\)?

Excerpt from The Algorithm Design Manual: Shape similarity is a problem that underlies much of pattern recognition. Consider a system for optical character recognition (OCR). We have a known library of shape models representing letters and the unknown shapes we obtain by scanning a page. We seek to identify an unknown shape by matching it to the most similar shape model.

The problem of shape similarity is inherently ill-defined, because what ``similar'' means is application dependent. Thus no single algorithmic approach can solve all shape matching problems. Whichever method you select, expect to spend a large chunk of time tweaking it so as to achieve maximum performance. Don't kid yourself -- this is a difficult problem.


Shape similarity testing via turning functions (rating 8)
SegMatch (rating 8)
svmjs (rating 7)
KML (rating 7)
SVMlight (rating 7)
LIBSVM (rating 7)
SNNS (rating 5)

Recommended Books

Algorithms for Clustering Data by A. Jain and R. Dubes Pattern Classification and Scene Analysis by R. Duda and P. Hart

Related Problems

Graph Isomorphism

Medial-Axis Transform

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