Research On Detection Algorithm For Surface Defects Of High Reflector

The high reflector is an important optical element in many optical systems,and its quality directly affects the performance of the optical system.Especially for some precision optical systems,the surface defects(or imperfections)of the high reflector will directly reduce the performance parameters of the system.Such as the the surface defects of high reflector that composes the ring resonator of the laser gyroscope will cause the light scattering in the gyroscope optical path,especially the back scattered light and the forward scattered light are more easily coupled to the forward and backward two propagating working beams to increase the lock area of the laser gyroscope,so that the the measurement sensitive area of laser gyroscope is influenced.Because its reflectivity is greater than 99.99%,the detection accuracy of surface defects is high,it is difficult to obtain complete surface defect information,and it is easily affected by stray light.Therefore,the surface defect detection of high mirror is the focus and difficulty of gyroscope quality evaluation now.Based on the microscopic scattering imaging measurement system and image processing technology,this paper digitally evaluates the two.dimensional information of the high mirror's surface defects,and focuses on the detection algorithms of surface defects.Combined with the measurement of the scattering rate of surface defects by the integrated scattering rate measurement system,the problem of the difficulty of measuring the depth information of micron.level surface defects is indirectly solved.Completed the comprehensive characterization of surface defects with multiple parameters.This paper theoretically analyzes the relationship between surface defects and scattering rate and surface roughness,uses Matlab to simulate and calculates the influence of surface defects of different sizes on the surface roughness,and analyzes and calculates the precision requirements for the detection of surface defects of high reflectors.A measurement system was built based on the micro.scattering imaging method,and motion control and image acquisition software was designed.Through the translation and rotation scanning of the sample,the surface defect images of different light directions were obtained.The detection algorithm of surface defects is studied,the noise of the surface defect image is filtered through the NLM algorithm,the surface defect image is segmented by the image fusion and OSTU algorithm,which can effectively avoid the influence of stray light,and the surface defect is realized based on the BP neural network.Image recognition and classification can accurately distinguish pits and scratches.The length,width,area and other information are extractedOptimized the integrated scattering rate measurement system,designed the lock.in amplifier control and data processing software,realized the measurement of the scattering rate of the area of interest for the surface defect of the high reflector,and screened out the high reflector integrated with the total integrated scattering rate?100ppm to evaluate the surface quality of the high reflector.Finally,through the analysis and calculation of the errors caused by the software and related algorithms in this paper,the feasibility of the software and the algorithm is verified,which can meet the detection requirements of the surface defects of the high reflector,and finally achieve the smallest diameter range of ?3mm on the high reflector.For the detection of surface defects on the order of 3?m,high.reflection mirrors that meet the surface defect detection standards are screened to guide the assembly of the laser gyroscope.The research results have certain guiding significance for the use of machine vision technology to evaluate the surface quality of high.reflection mirrors.