A compleled method of Calibration of Lens-induced Distortion is discussed,which on a test photographing. It is described as following: take some pictures on a test target; the signs on the pictures are marked and matched by computer automatically; the parameters of lens-induced distortion can be calculated using least square procedure. The algorithm of automatic marking and matching test target is detailed, which contains several approaches: image pre-processing, image binaryzation, image segmentation, sig...