In-Situ Surface Inspection Using White Light Channelled Spectrum Interferometer

Abstract

We introduce a new environmentally robust optical interferometry system for fast surface profile measurement. The proposed white light channelled spectrum Interferometer (WLCSI) is effective for applications in on-line surface inspection because it can obtain a surface profile in a single shot. Compared to the traditional spectral interferometry techniques, cylindrical lens is used in the Michelson interferometric objective of our system to achieve the measurement of long profiles. Combined with a modern high speed CCD camera, general-purpose graphics processing unit (GPGPU) and multi-core processors computing technology, large dynamic measurement with a high signal-to-noise ratio is realized. The designed prototype of WLCSI is presented and its performance was evaluated experimentally by measuring two surface samples. The measuring results closely align with the calibrated specifications given by the manufacturer as well as the measurement results by the other commercial instrument, which shows that the proposed WLCSI could be applied to production line like the roll-to-toll (R2R) surface inspection where only defects on the film surface are concerned in terms of the quality contro