Stereo-PIV using self-calibration on particle images
Stereo-PIV using self-calibration on particle images
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DOI：
10.1007/s00348-005-0962-z
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发表时间：
2005-05
影响因子：
2.4
通讯作者：
B. Wieneke
中科院分区：
文献类型：
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作者：
B. Wieneke
基于使用 3D 校准板的单个或多个视图将相机针孔模型拟合到两个相机，开发了立体 PIV（立体粒子图像测速）校准程序。通过相机 1 和 2 的图像的互相关，在真实粒子图像上计算视差矢量图，以确定校准板是否与光片重合。根据视差矢量，拟合光片在空间中的真实位置，并相应地校正映射函数。结果表明，即使校准板距离光片很远，也可以导出准确的映射函数，从而使校准过程变得更加容易。已实施改进的 3 介质相机针孔模型，以考虑沿光路的折射率变化。然后可以在封闭的流动池外部进行校准并对记录进行自校准。该方法允许在封闭的测量空间内进行立体 PIV 测量，这在以前是不可能的。根据计算出的相关图，可以导出两个激光光片的位置和厚度，以确定两个激光光片的厚度、重叠程度和平坦度。
A stereo-PIV (stereo particle image velocimetry) calibration procedure has been developed based on fitting a camera pinhole model to the two cameras using single or multiple views of a 3D calibration plate. A disparity vector map is computed on the real particle images by cross-correlation of the images from cameras 1 and 2 to determine if the calibration plate coincides with the light sheet. From the disparity vectors, the true position of the light sheet in space is fitted and the mapping functions are corrected accordingly. It is shown that it is possible to derive accurate mapping functions, even if the calibration plate is quite far away from the light sheet, making the calibration procedure much easier. A modified 3-media camera pinhole model has been implemented to account for index-of-refraction changes along the optical path. It is then possible to calibrate outside closed flow cells and self-calibrate onto the recordings. This method allows stereo-PIV measurements to be taken inside closed measurement volumes, which was not previously possible. From the computed correlation maps, the position and thickness of the two laser light sheets can be derived to determine the thickness, degree of overlap and the flatness of the two sheets.