粒子像斑三维定位的透视成像原理和方法

Prospective image arithmetic of particle positioning in 3-D PIV

在三维粒子成像测速 (PIV)方面 ,可运用体积光照明同时从不同光轴用多个照相机获得PIV图像 ,如何根据这些不同光轴获得的PIV图像确定出粒子物点的空间位置是实现三维粒子成像测速的前提。基于此 ,提出了根据多幅不同光轴的PIV图像的粒子像斑实现粒子物点三维定位的透视成像定位原理和方法。精确确定透视平面与透视中心在空间的位置是实现粒子物点三维定位的关键 ,直接测定透视中心 (照相机的光学中心 )和透视平面在空间的精确位置用常规的测量手段和方法难以奏效 ,因而针对透视图像成像特征及规律进行了较为深入地研究探讨 ,这对于寻求精确计测透视中心和透视平面空间位置的方法有着重要意义。作为实例 ,还给出了两光轴夹角为 90°情况下实现粒子物点三维定位的一系列具体方法和有关算法及定量关系。

In spatial illumination two cameras set along different visual lines are often used in 3 D PIV methods. How to determine the 3 D positions of the particles according to the two images obtained by the cameras is most important in the methods. This paper proposes a method based upon the principle of prospective image for determining the 3 D positions of the particles seeded in a flow field. Meanwhile, for an instance of the visual lines perpendicular each to other, the arithmetic of 3 D particle position and relative expressions is given in this paper.