Distortion measurement of CCD imaging system with short focal length and large-field objective

The measuring technology for high-distortion TV images taken by CCD imaging system with short focal length and large-field objective is investigated carefully. According to the principle of optical measurement, a camera model accounting with polynomial descriptions of distortion coordinates. Polynomial fitting is much better than others presented in literatures about camera calibration. Optical center is successfully pre-determined by laser self-alignment and software optimization, whose error of location is less than 0.01 pixel. To locate each sample dot in the high distortion (36%) image, a horizontal and a vertical grating is used. Using the equipments and software developed in experiments, the distortion of the CCD imaging system with focal length f ′ = 2.6 mm and view-field 120° is measured accurately. The measurement precision is 0.2%. The method can be applied in practice.