一种新的三维PIV自标定技术  

Novel Self-calibration in Stereo-PIV

作　　者：刘艳[1] 董守平[1] 

机构地区：[1]中国石油大学流体测试实验室,北京102249

出　　处：《科学技术与工程》2007年第21期5485-5488,5509,共5页Science Technology and Engineering

摘　　要：相机标定是获取相机内外部方位参数的过程。利用体视投影匹配确定的标定参数,就能从两幅体视照片中确定视场内一点的三维位置。提出一种新的在三维PIV测量中使用的相机自标定技术。该方法只需要测量现场的任意八个不相关点和一个标定长度做参照,就可实现流场的自标定,完全不需要再测试现场放置标定体,更不需要已知相机的内外方位元素。该标定方法分为两步:第一步标定相机内方位元素:由三灭点定理确定体视相机的初步标定参数;第二步标定实际流场:利用同源像线与基线必定确定一平面作为优化约束,对第一步取得的参数进行非线性优化。实验证明,该方法行之有效。Camera calibration is a process to acquire camera＇s intrinsic and extrinsic parameters.Using these parameters,the 3-D position of a point in the scene,which is identified and matched in two stereo images,can be determined.A new self-calibration method in stereo-PIV system is presented with volume-light source based on camera pinhole model.The proposed calibration procedure consists of two steps.In the first step,the calibration parameters are estimated by self-calibration using three vanishing-points theorem in two perspective picture.In the second step,the parameters estimated in the first step are improved iteratively through a nonlinear optimization,based on the coplanarity condition,taking into account camera distortions.This works well if there are three sets of parallel lines independently in the view scene.Only one global distance scale is needed.

关 键 词：三维PIV(3DPIV) 自标定 灭点 非线性优化 共面约束 

分 类 号：O353[理学—流体力学] TV131[理学—力学]