Development of an instrument for measuring curvature of lens

摘要

A new edge detection method based on nonlinear fitting is used in the measurement of the curvature of lens in this paper. Non-contact Newton's rings are formed by an interferometer. In order to detect the diameters of dark rings and calculate the lens radius of curvature, the edge detection method is used for the image process. The auto-measuring system of lens curvature captures the gray scale image by CMOS image sensor, and then processes the data and calculates the position by a microprocessor. The scale of image pixels corresponding to Newton's rings that are related to the radius of curvature is obtained by scanning fringes or other optical methods. The accuracy of measurement is better than 0.3 percent.