The Research On Automatic Measurement Of The Circular Optical Element Profile

Among the optical elements, circular optical elements are most widely used, such as a lens. The profile size of the optical element is the foundation to ensure that the element can be used normally.Therefore,in this thesis, the detection of circular optical element profile is studied deeply.Firstly, it is found that the detection of circular optical element profile,which is still in the stage of manual and contact measurement.The detection can't meet the need of industrial production.So it's necessary to look for efficient and accurate detection method.Secondly, the existing measurement methods of diameter and cylindrical are analyzed, and the scheme for the cylindrical contour of circular optical element is designed.The devices of measurement system is designed by analyzing the applications of various light as well as parameters of lens and combing with the scheme and measurement requirements.Then the experimental platform is built to acquire the cylindrical contour images.According to the resulting image,combining threshold segmentation and vertical projection which used for acquiring target position,the method of extracting target information based on scanning press performed of image is proposed.lt can effectively extract useful information automatically extraction.Then,sub-pixel detection algorithm to obtain the edge data is chosen by analyzing and comparing various algorithm for edge detection.Finally, the diameter and cylindricity of the circular optical element is calculated. According the edge data, the diameter is calculated by least square method.Cylindrical is obtained by building the objective function according the minimum zone method, as well as the algorithm is optimized by using MATLAB. It is given a method to eliminate error of the axis of rotation.In this thesis, using machine vision technology,the research on detecting the diameter and cylindricity of the circular optical element is studied including theory and experiment,providing direction for industry to detect optical elements.