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Proceedings Paper

Direction-dependent tangent: a new tangent representation
Author(s): Wai-Him Wong; Horace H. S. Ip
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Paper Abstract

Many techniques in machine vision require tangent estimation. In many implementations, the acquired tangent estimates are sensitive to coding direction of the curves in interest. Therefore, it is a common practice to enforce a certain coding scheme, for example, a boundary is traced in the counterclockwise manner. However, this scheme guarantees to work only for closed curves. For open curves, an inverse operator seems to be a must. In this paper, we propose a new tangent representation scheme named direction-dependent tangent (DDT). DDT makes explicit the direction of curve following and incorporates concavity information into the tangent orientation. The scheme is a simple but powerful enhancement to the standard tangent notation. It facilitates shape matching type of tasks by removing the need for either a predefined coding direction or an inverse operator.

Paper Details

Date Published: 23 March 1995
PDF: 5 pages
Proc. SPIE 2421, Image and Video Processing III, (23 March 1995); doi: 10.1117/12.205481
Show Author Affiliations
Wai-Him Wong, City Polytechnic of Hong Kong (Hong Kong)
Horace H. S. Ip, City Polytechnic of Hong Kong (Hong Kong)

Published in SPIE Proceedings Vol. 2421:
Image and Video Processing III
Robert L. Stevenson; Sarah A. Rajala, Editor(s)

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