Single-shot profilometry of rough surfaces using hyperspectral interferometry

• Autores: Pablo D. Ruiz, Jonathan M. Huntley, Taufiq Widjanarko
• Localización: SPECKLE 2012: V International Conference on Speckle Metrology : 10-12 september 2012 : Vigo, Spain / Ángel Manuel Fernández Doval (ed. lit.), María Cristina Trillo Yáñez (ed. lit.), José Carlos López Vázquez (ed. lit.), 2012, ISBN 9780819490902
• Idioma: inglés
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• Resumen

  • The measurement of surface profile is a vital quality control procedure in many industries. For small objects (dimensions below ~10 mm) with rough or discontinuous surfaces, scanning white light interferometry (SWLI) is currently the method of choice. However, with a resolution of ~1 nm, vibration during the scan induces motion artifacts and prevents its routine use on the production line. We present a system that avoids temporal scanning by spectrally splitting the white light interferogram into a set of interferograms at different wavenumbers which are recorded simultaneously on an image sensor. The system essentially consists of an interferometer coupled to a single-shot hyperspectral imaging system. Fourier transformation along the wavenumber axis provides an absolute optical path difference for each point in the field of view, a procedure which is robust even on optically rough surfaces. Height maps with a spatial resolution of 19×19 pixels and a measurement accuracy of ~460 nm are demonstrated