Study of the Measurement of Corneal Surface Profile with Heterodyne Moiré Method

• Main Authors: TSUNG-MIN CHEN, 陳聰閔
• Other Authors: KUN-HUANG CHEN
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/10577271281249829381

碩士 === 逢甲大學 === 電機工程學系 === 101 === This study proposes an accurate method for reconstructing the corneal surface profile. By applying a constant velocity to the projection grating along the grating plane, a series of sampling points of the sinusoidal wave, which behaves in the manner of heterodyne interferometric signals, can be recorded using a CMOS camera. The phase distribution of the corneal surface profile can then be obtained using the IEEE 1241 least-square sine fitting algorithm and two-dimensional (2D) phase unwrapping. Finally, the corneal surface profile can be reconstructed by substituting the phase distribution into a special derived equation. To validate the proposed method, a corneal surface of a pig eyeball was measured. The measurement resolution was approximately 2.9 um. Because of the introduction of the Talbot effect, the projection moiré method, and heterodyne interferometry, this approach provides the advantages of a simple optical setup, ease of operation, high stability, and high resolution.