Paper
4 April 1994 Studies of Fourier transform profilometry
Author Affiliations +
Proceedings Volume 2178, Visual Data Exploration and Analysis; (1994) https://doi.org/10.1117/12.172067
Event: IS&T/SPIE 1994 International Symposium on Electronic Imaging: Science and Technology, 1994, San Jose, CA, United States
Abstract
This paper presents a comparison between two different optical geometries used in Fourier Transform Profilometry (FTP); crossed- optical-axes geometry and parallel-optical-axes geometry. A mathematical proof is presented to demonstrate that parallel- optical-axes geometry can provide a wider range of measurement than crossed-optical-axes geometry. The FTP method decodes the 3- D shape information from the phase information stored in a 2-D image of the object onto which Ronchi grating is projected. The phase information can be separated from the image signal by two methods; the phase subtraction method and the spectrum shift method. An experimental comparison between two phase extraction methods is presented. The results show that the phase subtraction method is less susceptible to nonlinearity of recording media and systematic optical geometry error. On the other hand, the spectrum shift method is faster in terms of computing time and noise immune. The experimental comparison also demonstrates a noise immune phase unwrapping strategy, based on a minimum spanning tree approach, to form a contiguous map of the object surface.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ping-Hai Chan, Peter John Bryanston-Cross, and John T. Judge "Studies of Fourier transform profilometry", Proc. SPIE 2178, Visual Data Exploration and Analysis, (4 April 1994); https://doi.org/10.1117/12.172067
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KEYWORDS
Fourier transforms

Phase shift keying

Projection systems

Cameras

Modulation

Image sensors

Ronchi rulings

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