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Proceedings Paper

Subpixel localization of synthetic references in digital images by use of noncomposite and composite augmented templates
Author(s): Wim M. Ruyten
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Paper Abstract

A new method is presented for the localization of synthetic references (SRs) in digital images based on normalized correlation. An augmented search template is used, which consists not only of occupied pixel fractions of the SR, but also of derivatives of these fractions with respects to shifts along the image axes. Resulting correlation values are higher than those based on standard correlation, especially for small SRs and unfavorable subpixel displacements between template and scene. The augmented template is also used to determine the location of the SR to subpixel accuracy. The precision of this determination is affected less by systematic and random error than is the case for centroiding or sampled correlation interpolation, and can be estimated explicitly from the calculated correlation value. Numerical examples are given and the algorithm is demonstrated on data taken in wind-tunnel tests under different lighting conditions. In particular, the situation is considered in which imaged SRs display poor contrast, mixed contrast, or are affected by other experimental artifacts such as specular reflection and partial occlusion. In these cases, successful subpixel localization is accomplished by treating the template as a composite set of overlapping 3-by-3 subtemplates.

Paper Details

Date Published: 22 May 2002
PDF: 10 pages
Proc. SPIE 4667, Image Processing: Algorithms and Systems, (22 May 2002); doi: 10.1117/12.467975
Show Author Affiliations
Wim M. Ruyten, Sverdrup Technology, Inc. (United States)

Published in SPIE Proceedings Vol. 4667:
Image Processing: Algorithms and Systems
Edward R. Dougherty; Jaakko T. Astola; Karen O. Egiazarian, Editor(s)

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