视觉测量系统中一种独立的畸变校正算法

针对视觉测量系统中畸变校正的计算过程复杂、 操作调整繁琐等问题,提出一种 基于虚拟模板的逐点畸变校正方法。首先基于交比不变性原理、镜头畸变特点和双线 性插值法,求解单幅虚拟平面模板内特征光点所对应成像点的理想坐标及其畸变修正量； 再通过单幅虚拟模板运行轨迹的小幅度旋转与平移,逐步构成一块包含密集校正光点的虚拟 畸变校正模板,为镜头畸变修正提供足够的插值节点；而后采用Delaunay三角剖分(DT)技术 ,最 终在整个像平面内逐点地校正各类镜头畸变,形成包含全部像素点理想坐标及畸变修正 量的畸变修正数据表。实验表明,经独立畸变校正的视觉系统,其测点反投位置偏差的标准 差达0.015mm、最大值仅0.068mm；本文方法 能有效地修正畸变,有助于提高视觉系统的测量精度。

Independent distortion correction algorithm in vision measurement system

There are some projected problems during the distortion correction pro cess in vision measurement system,such as complex calculation process,minu te operating or adjusting.Hence,a novel point-to-point distortion correction algorithm based on virtual template is proposed in this paper.Based on cross-r atio invariability,characteristics of lens distortion and bilinear interpolation alg orithm,all ideal coordinates of corresponding image points projected from a sing l e virtual plane template are solved.And the distortion modified values are calc ulated on the basis of shifting between ideal and actual coordinates.Then,narr ow-range rotations and translations of template running trace are executed.So a virtual distortion correction plate with dense feature light spots is formed st ep by step,which supplies sufficient interpolation nodes for distortion modific ation.Finally,all kinds of lens distortions located in the whole image plane are corrected point by point by adopting Delaunay triangulation (DT) technology.And a d istortion modified data table is set up,which contains ideal coordinates and dis tortion modified values of all pixels.The experimental results demonstr at e that the standard deviation of projection distance deviations acquired by the independent correction method is 0.015mm,and the maximum error is merely 0.068mm.T he independent method could effectively correct lens distortion and has benefit for improving vision measurement accuracy.