Corneal surface reconstruction by using heterodyne Moiré method

Wei-Yao Chang; Kun-Huang Chen; Der-Chin Chen; Jung-Kai Tseng; Shyan-Tarng Chen; Han-Ying Sun; Jing-Heng Chen; Ken Y. Hsu

doi:10.1117/12.2020423

23 May 2013 Corneal surface reconstruction by using heterodyne Moiré method

Wei-Yao Chang, Kun-Huang Chen, Der-Chin Chen, Jung-Kai Tseng, Shyan-Tarng Chen, Han-Ying Sun, Jing-Heng Chen, Ken Y. Hsu

Author Affiliations +

Proceedings Volume 8792, Optical Methods for Inspection, Characterization, and Imaging of Biomaterials; 87920B (2013) https://doi.org/10.1117/12.2020423
Event: SPIE Optical Metrology 2013, 2013, Munich, Germany

Abstract

In this paper, we propose a simple method for reconstructing the corneal surface profile by using the Talbot effect, projection moiré method, and heterodyne interferometry. A linear grating is obliquely illuminated by an expanding collimated light, and a self-image of this grating can be generated and projected on the corneal surface. The deformed grating fringes are imaged on the second grating to form the moiré fringes. If the first grating is moved with a constant velocity along the grating plane, a series of sampling points of the sinusoidal wave which behave like the heterodyne interferometric signal can be recorded by a CMOS camera. The phase distribution of the corneal surface then can be obtained with the IEEE 1241 least-square sine fitting algorithm and 2D phase unwrapping. Finally, the corneal surface profile can be reconstructed by substituting the phase distribution into special derived equation. This method provides the advantages of a simple optical setup, ease of operation, high stability, and high resolution.

Citation Download Citation

Wei-Yao Chang, Kun-Huang Chen, Der-Chin Chen, Jung-Kai Tseng, Shyan-Tarng Chen, Han-Ying Sun, Jing-Heng Chen, and Ken Y. Hsu "Corneal surface reconstruction by using heterodyne Moiré method", Proc. SPIE 8792, Optical Methods for Inspection, Characterization, and Imaging of Biomaterials, 87920B (23 May 2013); https://doi.org/10.1117/12.2020423

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