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Proceedings Paper

The research on the moire fringe image preprocessing
Author(s): Xiao-guo Xiao; Ming-wu Ao; Chun-ping Yang; Ruo-fu Yang
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Paper Abstract

Based on Talbot effect and Moiré fringes of Ronchi gratings which is defined as Moiré Deflection Technology (MDT), lenses' power is calculated. Moiré Deflection Technology can be used for non-contact measurement of phase objects and surfaces and MDT is more widely used in the lenses' power measurement. The power of measured lenses can be figured out accurately according to the relationship between moiré fringes tilting angle and the tested lens's power. Area array CCD recorded moiré fringe image generated by two gratings mechanical interference to measure lenses' power. After appropriate digital image processing such as gray scale equality, image enhancement, image thinning etc, the moiré fringes image is processed by thinning to single pixel width. The pixels of the moiré fringes are labeled to fitting lines to calculate the slope coefficients. However, the moiré fringe image appears to have an unequal light distribution. Based on this phenomenon, a binary processing method, which is based on background gray-scale extension, was proposed. At first, a statistical method is used to calculate gray values from a sampling image with block-based processing. Then the linear interpolation is employed to generate new gray values instead of image pixels to obtain a background image and the moiré fringe image should be corrected by the obtained background image. At last, binarized the image by 2D OTSU threshold algorithm. The experimental results show that the method is simple and effective to segment the moiré pattern from the original moiré fringe image. This method can be used to improve precision of lenses measurement.

Paper Details

Date Published: 18 August 2011
PDF: 8 pages
Proc. SPIE 8194, International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, 81941A (18 August 2011); doi: 10.1117/12.900127
Show Author Affiliations
Xiao-guo Xiao, Univ. of Electronic Science and Technology of China (China)
Ming-wu Ao, Univ. of Electronic Science and Technology of China (China)
Chun-ping Yang, Univ. of Electronic Science and Technology of China (China)
Ruo-fu Yang, Univ. of Electronic Science and Technology of China (China)


Published in SPIE Proceedings Vol. 8194:
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications
Makoto Ikeda; Nanjian Wu; Guangjun Zhang; Kecong Ai, Editor(s)

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