Jinhuan LI, Osami SASAKI and Takamasa SUZUKI

Faculty of Engineering, Niigata University, Niigata 950-2181, Japan

(Received April 15, 2002; Accepted May 24, 2002)

A method for accurately measuring a sectional profile of a cylinder is proposed in which a sinusoidally vibrating sinusoidal grating is used to generate a sinusoidally vibrating sinusoidal intensity distribution. A light coming from the top point of the cylinder surface is extracted with an optical system to make an image of this point. A sectional profile of the cylinder is measured by detecting a phase of a time-varying signal contained in the image intensity at a position where the amplitude of the signal is maximum. Detection of the amplitude and the phase is carried out easily and exactly.

Key words: grating, sinusoidal phase-modulation, sectional profile, optical imaging