Model-Free Lens Distortion Correction Based on Phase Analysis of Fringe-Patterns.

Jiawen Weng,Pan Qi,Jingang Zhong,Weishuai Zhou,Simin Ma

doi:10.3390/s21010209

Abstract

The existing lens correction methods deal with the distortion correction by one or more specific image distortion models. However, distortion determination may fail when an unsuitable model is used. So, methods based on the distortion model would have some drawbacks. A model-free lens distortion correction based on the phase analysis of fringe-patterns is proposed in this paper. Firstly, the mathematical relationship of the distortion displacement and the modulated phase of the sinusoidal fringe-pattern are established in theory. By the phase demodulation analysis of the fringe-pattern, the distortion displacement map can be determined point by point for the whole distorted image. So, the image correction is achieved according to the distortion displacement map by a model-free approach. Furthermore, the distortion center, which is important in obtaining an optimal result, is measured by the instantaneous frequency distribution according to the character of distortion automatically. Numerical simulation and experiments performed by a wide-angle lens are carried out to validate the method.

Highlights

Camera lenses suffer from optical aberration; the nonlinear distortion would be introduced into the captured image, especially for the lens with large field of view (FOV)
All the above-mentioned methods rely on some specific distortion models, such as the commonly used even-order polynomial model [16] proposed by Brown, division model [17] proposed by Fitzgibbon, and fisheye lens model [18]
By the plumb-line method with the single parameter division model, the phase analysis method by the even-order polynomial model with one and two model, the phase analysis method by the even-order polynomial model with one and distortion parameters and the single parameter division model, and the proposed modeltwo distortion parameters and single parameter and the proposed free method, the curvature radiuses of thethe corresponding correcteddivision lines on model, the corrected model-free method, the× 10 curvature corresponding corrected checkerboard images are 3.2821

Summary

Introduction

Camera lenses suffer from optical aberration; the nonlinear distortion would be introduced into the captured image, especially for the lens with large field of view (FOV). One relies on a known measuring pattern [5,6,7], including straight lines, vanishing points, and a planar pattern It estimates the parameters of the un-distortion function by a known pattern to achieve correction. The second is the multiple view correction method [9,10,11], which utilizes the correspondences between points in different images to measure lens distortion parameters. It achieves auto-correction without any special pattern but requires a set of images captured from different views. It should be noted that all these distortion models achieve ideal circular symmetry

Methods

Results

Discussion

Conclusion