The Automatic Undistortion Strength Estimation for Any Describable Optical Distortion

Abstract

A presence of an optical distortion does undesired influence on the geometrical image quality. The main reason of its occurring is using a lens with low or variable focal length or simple camera optics. When an image captured by a camera is affected by undesired distortion and it is used for the distance measurement, it can cause significant measurement errors. The aim of this paper is to introduce a method for finding an optimal undistortion parameter for any optical distortion, which can be described mathematically. The proposed method uses the Hough transformation accumulator and at each iteration step the quality of straight lines is evaluated as a gradient from local maximum. The algorithm is verified and assessed on several images. The developed approach can be used to find the global maximum gradient in general, even when a local maximum changes its size over iterations.