Study On Surface Detection Algorithm Based On 3d Reconstruction

In the traditional lens shape detection process,it is necessary to contact the sample to be measured.This will cause the lens to be tested because the friction will damage the surface finish.Therefore,the traditional measurement method has gradually been replaced by the rapidly developed interferometry.Optical interferometry is able to detect the surface deviation of optical elements without contact,and to avoid the wear of other objects.The surface type deviation of the object surface and the standard surface is used as the optical path difference to generate interference,and the physical information carried by the interferogram can be used to indirectly measure the shape deviation of the object through the image processing technology.In this paper,by using digital image processing algorithm to extract key information from a single interference image,reconstruction of the object under test relative deviation of 3D surface shape,calculation of surface shape deviation,and lay a foundation for realizing automatic face detection software.This paper firstly introduces the significance,background and development status of this subject,and then briefly introduces the evaluation index of optical surface deviation.Then,the phase extraction algorithm,process and 3d surface fitting are introduced.In this paper,we focus on the binary algorithm of interference fringes and the hierarchical calibration algorithm.In this paper,the processing flow of the interference fringe pattern includes binarization,refinement,removal of burrs,automatic calibration of order,and interpolation of boundary points.Finally,the wavefront reconstruction is carried out with Zernike polynomials.This article through studies comparing the advantages and disadvantages of the traditional method,choose the best solution interference stripes binarization,then for thinning binary stripe images to extract the centerline,deburring,connection fracture after skeleton line,according to the interference fringes of endpoints are the characteristics of the external on the circle,to extract the first each stripe skeleton line endpoint,then use the least squares solution of the circumscribed circle of skeleton line.Then,the problem of too few boundary data points is solved by automatically demarcating and fitting round boundary points.Finally,the three dimensional surface shape of the measured object is fitted out with the Zernike polynomial,and the deviation of the surface and the standard surface is calculated.The interference fringe processing algorithm in this paper is developed and implemented in Matlab 2014b platform,and the interferogram collected by the research group can be processed to achieve the desired effect.