Multi-wavelength single-shot interferometry

A new surface profiling technique is proposed, which enables us fast and robust 3D measurements with interferometric resolution and extended measurement range. It is accomplished by a newly developed multi-wavelength imaging system, which is easily and economically constructed by a commercially available RGB LED illuminator and a color camera. With this imaging system, we first developed a two-wavelength single-shot technique. Then we expanded it to three wavelengths and successfully measured a step height of 1000 nm. For this purpose, we developed several algorithms including crosstalk compensation and frequency estimation. The algorithms and experimental results are presented.