An Analytical Piecewise Radial Distortion Model for Precision Camera Calibration

TL;DR

This paper introduces a new piecewise radial distortion model for camera calibration that offers improved flexibility and analytical undistortion, outperforming traditional polynomial models especially for low-quality cameras.

Contribution

A novel piecewise radial distortion model with an analytical undistortion formula, providing better accuracy and flexibility than polynomial models in camera calibration.

Findings

Better distortion correction performance than single-function models

Comparable results to polynomial models with fewer parameters

Effective for low-quality camera manufacturing distortions

Abstract

The common approach to radial distortion is by the means of polynomial approximation, which introduces distortion-specific parameters into the camera model and requires estimation of these distortion parameters. The task of estimating radial distortion is to find a radial distortion model that allows easy undistortion as well as satisfactory accuracy. This paper presents a new piecewise radial distortion model with easy analytical undistortion formula. The motivation for seeking a piecewise radial distortion model is that, when a camera is resulted in a low quality during manufacturing, the nonlinear radial distortion can be complex. Using low order polynomials to approximate the radial distortion might not be precise enough. On the other hand, higher order polynomials suffer from the inverse problem. With the new piecewise radial distortion function, more flexibility is obtained and the radial undistortion can be performed analytically. Experimental results are presented to show that with this new piecewise radial distortion model, better performance is achieved than that using the single function. Furthermore, a comparable performance with the conventional polynomial model using 2 coefficients can also be accomplished.