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Optical model of hyperparaboloid mirror surface measurment based on PMD method

Phase measuring deflectometry (PMD) is used to measure the shape of the highly reflective hyperparaboloid mirror. The potical model of PMD was constructed by the aid of Zemax software, and the shape was reconstructed according to both the distorted fringes and the optical parameters, such as the distance between the text mirror and the LCD screen or the CCD camera, the off-axis distance of specular surfaces and the relative position between the screen and the camera. The slope of the text surface was obtained with the four-step phase-shifting method, phase unwrapping and camera calibration, and the shape of the hyperparaboloid mirror was restored by integrating the slope data, which provided a technical reference for the next actual measurement model.