Distortion error model of image of ellipse center in 3D visual inspection

In 3D visual inspection applications, there usually exists a distortion error of the CCD camera's pin-hole image of ellipse center. To address this problem, a mathematical model of this distortion error on the image plane of the CCD camera was established based on the theory of perspective projection and the theory of spatial analytic geometry. As it can quantificationally compensate the distortion error according to the parameters of vision system and the position and geometrical parameters of the inspected object, the proposed model provides a valuable theoretical reference for the inspection of the centers of the circular holes (elliptical holes) or cylindrical (cylindroid) workpieces, for the inspection application of structured-light based 3D vision and for the calibration of the intrinsic parameters of CCD cameras.