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光流算法和物理性较强的LS光流算法两大类算法进行结合,实现高精度的流场实时显示。通过人工合成粒子图像测试和拖曳水槽装置,系统测试了算法的效率、精度和鲁棒性,并与互相关算法进行比较。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,LK-S&LS算法计算精度及鲁棒性最高,均方根和角误差分别为0.073和1.56,且抗噪声能力最强,互相关算法的耗时则为1500 ms,均方根误差和角误差为0.128和3.13,明显劣于其他几种光流算法。在基于拖曳水槽的实验测试中,LK和LK&LS耦合算法均可实现近尾流区速度场及涡量场快速显示,其中,LK&LS算法的流场噪点最少,互相关算法噪点最多。本研究还可为后续实时控制问题下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 Liu-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 15ms. 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 1500ms, 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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