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Proceedings Paper

Focusing techniques
Author(s): Murali Subbarao; Tae-Sun Choi; Arman Nikzad
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Paper Abstract

We use the paraxial geometric optics model of image formation to derive a set of camera focusing techniques. These techniques do not require calibration of cameras but involve a search of the camera parameter space. The techniques are proved to be theoretically sound. They include energy maximization of unfiltered, low-pass filtered, high-pass filtered, and band-pass filtered images. It is shown that in the presence of high spatial frequencies, noise, and aliasing, focusing techniques based on band-pass filters perform well. The focusing techniques are implemented on a prototype camera system named SPARCS. The architecture of SPARCS is described briefly. The performance of the different techniques are compared experimentally. All techniques are found to perform well. One of them -- the energy of low pass filtered image gradient -- which has better overall characteristics is recommended for practical applications.

Paper Details

Date Published: 1 November 1992
PDF: 12 pages
Proc. SPIE 1823, Machine Vision Applications, Architectures, and Systems Integration, (1 November 1992); doi: 10.1117/12.132073
Show Author Affiliations
Murali Subbarao, SUNY/Stony Brook (United States)
Tae-Sun Choi, Kwangju Institute of Science and Technology (South Korea)
Arman Nikzad, Symbol Technologies Inc. (United States)

Published in SPIE Proceedings Vol. 1823:
Machine Vision Applications, Architectures, and Systems Integration
Bruce G. Batchelor; Susan Snell Solomon; Frederick M. Waltz, Editor(s)

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