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Optical Engineering

Further improvement of edge location accuracy of charge-coupled-device laser autocollimators using orthogonal Fourier-Mellin moments
Author(s): Jiubin Tan; Lei Ao; Ji-wen Cui; Wen-jing Kang
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Paper Abstract

In order to further improve edge location accuracies of charge-coupled-device laser autocollimators, we use rotation invariance and lower radial orders of orthogonal Fourier-Mellin moments to efficiently extract the characteristics of edges, set the edges in the vertical direction, and establish the expressions used for edge location. We accomplish this by analyzing the interrelationship of orthogonal Fourier-Mellin moments. We compensate errors caused by the differences between the masks selected (by correcting the locations in proportion to the dimensions of the masks selected) and by the differences between actual and ideal edge patterns (by correcting the bias errors in proportion to the distance from the center of the sampling area to the edge). Experimental results show that an edge location accuracy of 0.06 pixel can be achieved for straight lines, 0.08 pixel for curves, and ±0.12 pixel for an actual circular target acquired by a charge-coupled-device laser autocollimator. It is therefore concluded that the proposed method can be used as an efficient approach to achieve the higher edge location accuracies specified for such optoelectronic image measurements instruments as a charge-coupled-device laser autocollimator.

Paper Details

Date Published: 1 May 2007
PDF: 12 pages
Opt. Eng. 46(5) 057007 doi: 10.1117/1.2735287
Published in: Optical Engineering Volume 46, Issue 5
Show Author Affiliations
Jiubin Tan, Harbin Institute of Technology (China)
Lei Ao, Harbin Institute of Technology (China)
Ji-wen Cui, Harbin Institute of Technology (China)
Wen-jing Kang, Harbin Institute of Technology (China)

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