基于光流算法的流场实时显示研究

Research on real-time display of flow field based on optical flow algorithm

  • 摘要: 本文将效率较高的LK算法与物理性较强的LS算法相结合,以实现高精度的流场数据实时显示。通过人工合成粒子图像测试和拖曳水槽实验,系统评估了算法的效率、精度与鲁棒性,并与互相关算法进行了比较。在合成图像数据集测试中,LK-I算法的计算耗时最低,仅需15 ms;而LK-S & LS算法的计算精度与鲁棒性最高,其均方根误差和角误差分别为0.073和1.56,且抗噪声能力最强;互相关算法的计算耗时为1500 ms,均方根误差和角误差分别为0.128和3.13,明显劣于其他几种光流算法。在拖曳水槽实验中,LK算法及LK & LS算法均能实现近尾流区速度场与涡量场的快速显示,其中LK & LS算法所得流场噪点最少,互相关算法所得流场的噪点最多。本研究可为后续针对实时控制问题实现钝体减阻降噪提供一定的算法支撑。

     

    Abstract: In this paper, Lucas–Kanade (LK) optical flow algorithm with high efficiency and Lius–Shen (LS) optical flow algorithm with strong physical properties are combined to achieve high precision real-time display of the flow field. The efficiency, accuracy and robustness of the algorithm are tested by the synthetic particle image test and the towing flume device, which is compared with the cross-correlation algorithm. In the test of synthetic image data set, LK-I algorithm has the shortest computing time, only 15 ms. LK-S & LS algorithm has the highest computational accuracy and robustness, and its root-mean-square error and angular errors are 0.073 and 1.56 respectively with the strongest anti-noise ability. Cross-correlation algorithm takes 1500 ms, and its root-mean-square error and angular error are 0.128 and 3.13 respectively, so it is obviously inferior to the other two optical flow algorithms. In the experimental test based on the towing flume, both LK and LK & LS coupling algorithms can quickly display the velocity field and vorticity field in the near-wake region. The results show that LK & LS algorithm has the least flow field noisy points, while cross-correlation algorithm has the most noisy points. This research can also provide some algorithm support for the realization of blunt body drag and noise reduction in the following real-time control problems.

     

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