Structure and spectrum analysis of quasi-sinusoidal grating in phase measurement profilometry

In order to project sinusoidal fringe patterns onto the 3-D diffuse surface in the phase measuring profilometry(PMP),this paper presents a new method for designing quasi-sinusoidal grating.The sinusoidality of the image of the grating is improved by projecting such a grating onto an object surface by structured illumination,and by selecting the appropriate parameters of combination grating.The paper introduces the simulation of curve of intensity distribution and the development of the mathematical model of the designed quasi-sinusoidal grating,and the spectrum analysis of the quasi-sinusoidal grating.The fast Fourier transform spectra of the designed quasi-sinusoidal grating is of the same characteristics as the sinusoidal amplitude grating.The results provide a useful approach to design of quasi-sinusoidal grating.