采用条纹分析的镜头畸变测量与校正

Lens distortion measurement and correction by Fringe-pattern analysis

针对目前条纹模板测量法在图像畸变校正中所存在的过校正问题,文章采用载频条纹相位解调分析结合畸变模型实现对镜头桶形畸变的测量与校正。以载频条纹图像作为校正模板,使用广角镜头相机进行拍摄,获得畸变条纹图像;采用具有高空间局域特性的四步相移分析方法进行相位解调,获得畸变中心位置以及径向畸变量分布;根据桶形径向畸变的偶数阶多项式模型展开数值拟合分析,对畸变参量进行估算,结合畸变中心位置点参量,最终实现对畸变图像的校正。数值模拟以及实验结果表明,方法简单、有效,具有实际的应用价值。

Aiming at the over-correction problem of the fringe template measurement method in the lens distortion correction, the phase analysis of fringe-pattern combined with the distortion model is adopted to realize the measurement and correction of the lens barrel distortion. Firstly, the standard cosine fringe-pattern is employed as the measuring template and captured by the camera with wide-angle lens to obtain the distorted fringe-pattern. Four-step phase shifting analysis, which is excellent at spatial localization analysis, is employed for the phase analysis. And then the distortion center and the radial distortion phase are obtained. According to the even-order polynomial model of the radial distortion, the distortion parameters are calculated by numerical curve fitting. Finally, the image correction is achieved according to the distortion parameters and the distortion center. Numerical simulation and real distorted image experiments have been carried out to validate the method.