Research On Distortion Measurement And Calibration Technique For Automatic Tracking And Aiming Optical System Based On CCD

The automatic tracking and aiming optical system based on CCD is a photovoltaic system which is widely used in the domain of military. This system is composed of multiple sensors; it is a platform to capture, track and aim multiple targets, the performance of this system determines the weapon capability. However, the distortion seriously affects on the observation, measurement, positioning and analysis of the object, the high-precision image of registration and mosaic can not be obtained, the target characteristics can not be reflected accurately, which is the reason why the target tracking is wrong. The analysis accuracy, application effect and usage value are reduced, so distortion measurement and calibration become more important.The distortion measurement and calibration of the automatic tracking and aiming optical system based on CCD are researched in this paper. Firstly, the influence of the image quality which produced by distortion is analyzed theoretically and the characteristics of the system distortion are summarized and described. Secondly, according to the principle of camera calibration, in the premise of the internal parameter and the external parameter are calibrated, the distortion measurement system of automatic tracking and aiming optical system based on CCD is formed to get rid of the ocular examination and realize digital and objectification measurement by use of the high performance electronic target of high contrast, high brightness and excellent uniformity. Finally, by researching on the calibration technique, the inversion polynomial algorithm is proposed to calibrate the distortion according to the calibration precision, calculating time, instantaneity and experimental conditions. The calibrated precision of the inversion polynomial and positive polynomial are compared and verified by the experimental. The calibrated precision is affected by the number of target sample points, the degree of fitted polynomial and repeatability test. The calibrated result shows that the measurement precision using inversion algorithm can calibrate distortion of the system and the average distortion after calibration is better than 0.15%.