PIV技术自相关处理方法的研究(英)

A Study of Image Processing On PIV

本文介绍了用于处理PIV粒子图象速度场的两种自相关处理方法－平移和旋转，通过对两种处理方法进行分析和比较，我们看到旋转自相关处理方法能更好地处理带有较大速度梯度和旋涡的流场速度场。文中给出了两种处理方法的模拟流场的数值计算结果，并用两种处理方法对对称翼型流场的PIV图象进行了比较计算，得出较好结果。

To make Particle Image Velocimetry (PIV) more effective to the measurement of flow fields with steep velocity gradients and vortices, a new schema of digital image processing on conventional PIV is studied in this paper. We can compute velocity distribution on a planar domam of flow field with great velocity gradients.The new schema is suitable to be used in the image processing of PIV pictures of double-exposure. It is based on auto-correlation method. Comparing with the traditional method, this method considers the effect of out-of-pattern and velocity gradients within the patch. Out-of-pattem effect is the effect of the difference between the particle image pattern of the second exposure and that of the first exposure. Simulative calculations are performed, then results are compared and discussed. We have also prac-ticed the measurement of flow field around a symmetrical wing in a water tunnel. Results of velocity fields computed by different image pmeessing codes are compared, and several points have been concluded.