Research On 3d Reconstruction Algorithm Of Surface Defects Based On Scattering Distribution

With the continuous development of the modern optical industry,the application of precision optical components has become increasingly widespread in major fields such as aerospace,medicine,military,astronomy,and daily life.Optical systems composed of optical components have played an extremely important role in the field of optoelectronics such as high power lasers,large integrated circuits,and medical devices.In the use and development of various optical instruments,optical components play an extremely important role.Surface defects of optical components are caused by improper processing,and the scattered light produced by them can cause various hazards to the optical system,such as: reducing beam quality,triggering thermal effects,increasing system noise,reducing contrast,etc.,affecting the overall performance and normal operation of the optical system.Therefore,this paper conducts a study on the detection of three-dimensional dimensions of defects on the surface of optical components.The main research elements include:(1)In order to detect the surface defects of optical components by scattering method,only the CCD or CMOS sensor can receive the light field distribution formed by the scattering of surface defects and derive the two-dimensional dimensions of surface defects,but cannot directly detect the depth dimensions of surface defects,we propose a three-dimensional reconstruction of surface defects based on the scattering distribution.The phase distribution of surface defects is reconstructed first,and then the three-dimensional dimensional detection of surface defects of optical components is achieved based on the modulation characteristics of surface defects on the phase.(2)Based on the scattering model of the surface defects of optical elements,a simulation study of the 3D reconstruction algorithm of the surface defects of optical elements is carried out.Firstly,the angular spectrum propagation of light waves,scalar diffraction theory and the scattering theory of optical element surface defects are studied,based on which the scattering model of optical element surface defects is established;then the STIE method(Simple TIE,STIE)for the approximate solution of transport of intensity equation(TIE)is analysed,and the weighted angular spectrum iteration algorithm is proposed on the basis of the existing angular spectrum iteration algorithm,and the TIE algorithm is combined with the angular spectrum iteration algorithm and the weighted angular spectrum iteration algorithm,and the angular spectrum iteration algorithm,the weighted angular spectrum iteration algorithm,the TIE + angular spectrum iteration algorithm and the TIE + weighted angular spectrum iteration algorithm are applied to the detection of surface defects of optical components;finally,the convergence speed and reconstruction accuracy of these four 3D reconstruction algorithms are evaluated in terms of intensity error,relative root mean square error,correlation coefficient and structural similarity,respectively.Finally,the convergence speed and reconstruction accuracy of these four 3D reconstruction algorithms were evaluated in terms of intensity error,relative root mean error,correlation coefficient and structural similarity.The results show that all four 3D reconstruction algorithms can achieve 3D reconstruction of optical component surface defects,but the convergence speed of TIE+weighted angular spectrum iteration algorithm is faster and the reconstruction accuracy is better than the other three reconstruction algorithms.(3)The experimental setup was built based on the principle of defect detection by scattering method,and the experimental study of 3D reconstruction of surface defects of optical components was carried out.Firstly,the acquired surface scattering images of the optical element were preprocessed;then four 3D reconstruction algorithms were used to reconstruct the phase distribution of the optical element surface defects,and the detection of the 3D dimensions of the optical element surface defects was realized based on the modulation characteristics of the surface defects on the phase;finally,the reconstruction results were compared with the measurement results of the white light interferometer to calculate the relative error.The experimental results show that all four reconstruction algorithms can realize the 3D reconstruction of surface defects of optical elements,but compared with the other three reconstruction algorithms,the TIE+weighted angular spectrum iteration algorithm has the smallest reconstruction error and higher reconstruction accuracy.