[OPTICAL REVIEW Vol. 10, No. 4 (2003) 202-205]
© 2003 The Optical Society of Japan

Consideration of Fractional Fringe Method on the Basis of the Least Squares Method

Koichi IWATA, Jie ZHANG and Hisao KIKUTA

Department of Mechanical Systems Engineering, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuencho, Sakai, Osaka 599-8531, Japan

(Received March 5, 2003; Accepted April 28, 2003)

The traditional fractional fringe method has been applied to measure 1-dimensional size of a block gauge using multiple wavelengths. Recently, similar methods have been used in pattern interferometry and also in pattern projection profilometry. However, the technique does not seem to be based on a well-established principle. In this paper, the fractional fringe method is formulated on the basis of the least squares method and on its basis effects of errors in fractional fringes and wavelengths are analyzed and the effective selection of wavelengths is considered.

Key words: fractional fringe method, method of exact fractions, method of excess fractions, interferometry, pattern projection profilometry