Aerial image distortion correction algorithm based on polar coordinate Lagrange interpolation

Abstract

Since the height of aerial image shot is much lower than the height of satellite image shot, this may lead to the differences of the projection sizes and directions between every shooting location, which will result in serious picture distortion in most cases. In addition, the degree of distortion of the image edge region is much more serious than that in the center region, a distortion correction method based on Lagrange interpolation of polar coordinates has been proposed by this paper. We use this method to interpolate the single pixel in polar coordinates system. The pixel coordinate expression will be reconverted from polar coordinates to Cartesian coordinates after we corrected the pixel according the consequence of interpolation. And finally this method will be used to correct distortion pixel-by-pixel throughout the aerial image. The experiment results show that the corrected aerial image distortion does not exceed 3%, which proves that this algorithm can not only correct distortion image effectively, but also has a wide applicability compared with the traditional distortion correction methods, such as making use of the Direct Linear Transformation to obtain the distortion matrix.