基于光场成像的三维粒子追踪测速技术  

Three-Dimensional Particle Tracking Velocimetry Based on Light Field Imaging

作　　者：刘慧芳 周骛[1,2] 蔡小舒 周雷[1,2] 郭延昂 Liu Huifang;Zhou Wu;Cai Xiaoshu;Zhou Lei;Guo Yan′ang(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]上海市动力工程多相流动与传热重点实验室,上海200093

出　　处：《光学学报》2020年第1期213-223,共11页Acta Optica Sinica

基　　金：国家自然科学基金(51576130,51327803)。

摘　　要：将光场成像理论与三维颗粒追踪测速(PTV)技术相结合,实现了单相机三维流场的测量。结合高斯光学和相似原理,推导出了深度与最优重聚焦系数的关系。搭建了光场标定与流场测量系统,提出基于光场成像理论模型的深度标定方法,并与泰勒多项式拟合方法进行对比,证明了其具有较高的稳健性。利用清晰度最大原理,获得原始光场图像的全聚焦图,采用最小特征值角点检测算法对全聚焦图上的颗粒进行定位,结合三维粒子追踪技术,得到颗粒的三维速度。形成了光场PTV的图像处理流程,并对后向台阶流场进行了实测,结果表明光场PTV技术能够较好地测量三维流场。In this study,light field imaging theory and three-dimensional(3 D)particle tracking velocimetry(PTV)are combined to evaluate a 3 D flow field using a single camera.Further,a relation is derived between the depth and the optimal refocusing coefficient based on the Gaussian optics and the similarity principle.Subsequently,the light field calibration and flow field measurement systems are established.A depth calibration method is proposed based on the theoretical model of light field imaging.When compared with the Taylor polynomial fitting method,the proposed method is proved to have high robustness.An all-in-focus image is obtained based on the principle of maximum sharpness.The particles in the all-in-focus image are positioned using the corner detection algorithm based on the minimum eigenvalue;further,the 3 D velocities of the particles are obtained using the 3 D PTV technology.A processing flow is established for the light field images and applied to the flow field measurement on a back step.The results prove that the light-field-imaging-based PTV technology can reconstruct the volumetric flow field.

关 键 词：成像系统 光场成像 颗粒追踪 深度标定 后向台阶 

分 类 号：V211.71[航空宇航科学与技术—航空宇航推进理论与工程]