Radial geometrical distortion correction in image measurement system

Lens distortion in high precision imaging measurement system has to be strictly controlled, though the design and manufacture of this kind of lens are challenging. Thanks to the maturity of digital technical, image processing offers a new solution to correct the nonlinear distortion of lens. A set of simple and effective methods for detecting radial distortion center and calculating polynomial coefficients was proposed based on the analysis of a nonlinear camera model. Unitary linear regression analysis and gradually approach method were used to obtain the distortion center and recursive least squares estimation was used to get the polynomial coefficients, and images were corrected based on these data for fulfilling requirements. Test and simulation show the radial geometrical distortion can be accurately corrected in imaging measurement system by sampling one frame of image. It is simple and cost effective, could be used to calibrate camera distortion.