A 3D Profile Measurement Method Based on Color Composite Grating Projection

While the detected object contains depth discontinuities and large gradient, it is difficult to unwrap the wrapped-phase correctly because of the interrupted phase caused by height variations and background spectrum. So we bring a novel technique based on color composite grating, which contains two different colors and each color grating contain two different frequencies, generated by computer software. Through LCD projector project grating to the object's surface, it will be able to eliminate background spectrum through capture only one deformed grating, expanding the scope of measurement and solving the problem of the interrupted phase. Finally the feasibility of this method is provided through an analysis of the spectral aliasing in the deformed grating as well as computer simulation and experimental verification.