We propose a common-path two-wavelength intereferometric system based on a single optical element, a Savart Plate, able to obtain profile measurements at frame rate. To improve precision up to the sub-micron levels from safe working distances (beyond 100 mm), we use a speckle reduction system based on a rotating holographic diffuser. The interferometric signals of the two wavelengths are obtained simultaneously and their phase signals are combined to extend the measurement range. The system's common-path interferometry nature, and the possibility of acquiring a distance profile in a single frame, make it ideal for surface inspection in industrial environments.

Date Published: 17 June 2009
PDF: 9 pages
Proc. SPIE 7389, Optical Measurement Systems for Industrial Inspection VI, 73890W (17 June 2009); doi: 10.1117/12.827502

Published in SPIE Proceedings Vol. 7389:
Optical Measurement Systems for Industrial Inspection VI
Peter H. Lehmann, Editor(s)