Distortion correction for a wide-angle lens based on real-time digital image processing

Images captured with wide-angle lenses suffer from spatial distortion, which prevents accurate measure and feature extraction. In this work, a mathematical model based on polynomial mapping is used to map the images from distorted image space onto the corrected image space. The model parameters include the polynomial coefficients, distortion center, and dot center. A new technique to estimate the distortion center based on the evaluation function is presented. In dot center estimation, a seed fill algorithm is used to traverse all pixels. The expansion polynomial was obtained by using cubic spline interpolation. With a field programmable gate array (FPGA), the real-time distortion correction is implemented, which is independent of a computer. The major benefit using FPGA is that the same circuit can be used for other circularly symmetric wide-angle lenses without being modified.