Research On Analysis Method Of Interferogram Based On OSI-120SQ Interferometer

Interferometry Technology is based on the principle of interference of light. Optical interference measurement is an important method of detecting the surface of the optical element. And it has the advantage of high precision and non-contact measurement. Nowadays, the demand of optical devices is increasing day by day. The traditional manual method is difficult to meet the current needs of detecting and processing the optical devices in efficiency and detection accuracy. With the development of image sensing technology, computer technology and image processing technology, interference detection technology being developed to higher efficiency and higher automation.In order to achieve automatic and real-time interpretation of the fringes, this paper studies the methods of the computer interferometric image analysis. Through analysis of digital image processing technology, interference fringes are processed, the effective information of fringe are sampled. Eventually, through the Zernike polynomials to fit under measured wavefront, the surface shape information under measured component is obtained. Specific steps of interferogram fringe pattern analysis include interferogram fringe pattern enhancement, fringes binarization, stripe thinning, stripes centerline extraction, stripes sampling and polynomial fitting. The thesis use spatial processing approach to process interference images. Then use Householder transformation to solve Zernike polynomial coefficients. Through simulation experiments, the measurement biases of this approach are reasonable, which shows the effectiveness of the method.