An improved method of nonlinear distortion correction for wide-angle lens

This paper introduces an improved method of nonlinear distortion correction for wide-angle lens. The method is to cast chessboard image to the billiard table by the projector according to the given parameters, then to extract sub-pixel corners from the chessboard image collected by camera and establish fitting relations between coordinates of camera image and that of computer screen with the binary cubic polynomial. Through error compensation on the image coordinates in the nearby area based on each corner's error distribution, higher accurate mapping relation between the points on the billiard tabletop and those on the computer screen is obtained. Experiments show that the method is simple and feasible, which solves the problem of distortion correction of camera system with large field view and short focal length lens effectively and efficiently with the correction accuracy reaching the sub-pixel level, and is suitable for billiards teaching system and related fields.