Distortion measurement and calibration technology for CCD camera system based on new target board

The influence of testing map on distortion measurement and calibration is extensively studied. A so called 'one target distortion testing method' is presented for distortion measurement and calibration. The distorted image of the self-designed and fabricated 'integrated spot array target board' is recorded. The position of distorted points is determined by image processing, and compared with the ideal points position. The position relation between distorted points and ideal points is established by polynomial model. The position of ideal points is obtained by ideal imaging. Then polynomial coefficients of the model are computed from the least squares method. While corresponding the distorted points to ideal points, the whole CCD camera system's distortion is calibrated. The integrated spot array target board consists of gray spots and black interval belts, and makes it convenient to mark the spots in sequence and correspond the distorted points to the ideal points. The distortion of wide-angle CCD camera system with focal length of 2.6 mm is repeatedly measured and calibrated, and the calibrating precision is within 0.3%.