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Proceedings Paper

Digital Talbot interferometer
Author(s): Siu Chung Tam; Donald E. Silva; H. L. Wong
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Paper Abstract

A computer based automatic measuring instrument has been developed to compute the power distribution of progressive lenses. The measurement principle is based on Talbot interferometry in which the self image of a Ronchi grating is made to interfere with an analyzing grating of equal period. The fringe patterns produced are captured with a CCD camera and digitized with a Data Translation DT2851 frame grabber card. A C- language software package has been developed to perform fringe analysis using spin filtering, weighted averaging, and fringe centerline extraction with the binary derivative method. The power distribution is computed from the slope of the fringe centers. The instrument has been applied successfully to evaluate constant power and progressive power lenses.

Paper Details

Date Published: 1 March 1991
PDF: 11 pages
Proc. SPIE 1400, Optical Fabrication and Testing, (1 March 1991); doi: 10.1117/12.26115
Show Author Affiliations
Siu Chung Tam, Nanyang Technological Institute (Singapore)
Donald E. Silva, Polycore Optical Pte. Ltd. (Singapore)
H. L. Wong, Polycore Optical Pte. Ltd. (Singapore)

Published in SPIE Proceedings Vol. 1400:
Optical Fabrication and Testing
Manfred Lorenzen; Duncan R. J. Campbell; Craig Johnson, Editor(s)

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