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Proceedings Paper

Geometric matching algorithm for beam scanning
Author(s): Aaron S. Wallack; John F. Canny
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Paper Abstract

In this paper, we present an object recognition technique using scanline information. Objects are scanned using a small number of on/off light sensors. The times when the beams break and unbreak constrain the object's identity, position, and orientation. We study this type of sensor because they are inexpensive, compact, very precise, and insensitive to ambient light, and so well-adapted to manufacturing environments. The information provided by the sensor is very sparse however, consisting of isolated points on the object boundary without normal information. Conventional model-based matching techniques, such as the alignment method, take O(n3) time for this problem. We describe an O(A + n) correspondence algorithm for objects with convex polygonal silhouettes, where n is the silhouette's complexity, and A is the total number of consistent edge pair matches for pairs of scanline points, which is O(n2) in the worst case, but typically O(n). Our algorithm works also for non-convex objects, but the quantity A has a somewhat larger typical value, and a worst case value of O(n3). The object's position and orientation can be easily computed given the correspondence information.

Paper Details

Date Published: 1 December 1993
PDF: 18 pages
Proc. SPIE 2060, Vision Geometry II, (1 December 1993); doi: 10.1117/12.164990
Show Author Affiliations
Aaron S. Wallack, Univ. of California/Berkeley (United States)
John F. Canny, Univ. of California/Berkeley (United States)

Published in SPIE Proceedings Vol. 2060:
Vision Geometry II
Robert A. Melter; Angela Y. Wu, Editor(s)

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