21 September 1999 Shape measurement by multiple-wavelength interferometry
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Proceedings Volume 3824, Optical Measurement Systems for Industrial Inspection; (1999) https://doi.org/10.1117/12.364288
Event: Industrial Lasers and Inspection (EUROPTO Series), 1999, Munich, Germany
Abstract
Multiple-wavelength interferometry is a well-known technique which enables to increase the range of non-ambiguity for interferometry and to reduce the sensitivity of the measurement. Moreover, this technique is also applicable to rough surfaces. It is therefore of a great interest for shape measurement. We propose here a multiple-wavelength heterodyne interferometer with two-dimensional detection. Heterodyne technique requires synchronous detection of the heterodyne signal, which is not compatible with standard CCD. We used therefore a new type of CCD smart image sensor for two- dimensional synchronous detection at the heterodyne frequency. By applying an appropriate signal processing, distance measurements on rough surfaces were performed with a resolution of about 10 micrometer. By optimizing the illumination pattern on the target, only a few mW of total optical power is required for the measurements at several meter distance. This is of a great importance for an eye-safe system. Applications of this technique to shape measurements are discussed.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yves Salvade, Yves Salvade, Rene Daendliker, Rene Daendliker, } "Shape measurement by multiple-wavelength interferometry", Proc. SPIE 3824, Optical Measurement Systems for Industrial Inspection, (21 September 1999); doi: 10.1117/12.364288; https://doi.org/10.1117/12.364288
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