用于彩色光照粒子图像测速的粒子场模拟成像  

Particle Field Simulation Imaging for Color-illuminated Particle Image Velocimetry

作　　者：单良 施飞杨 洪波 王道档 熊俊哲 孔明 SHAN Liang;SHI Feiyang;HONG Bo;WANG Daodang;XIONG Junzhe;KONG Ming(Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province,College of Information Engineering,China Jiliang University,Hangzhou 310018,China;College of Metrology&Measurement Engineering,China Jiliang University,Hangzhou 310018,China)

机构地区：[1]中国计量大学信息工程学院,浙江省电磁波信息技术与计量检测重点实验室,杭州310018 [2]中国计量大学计量测试工程学院,杭州310018

出　　处：《光子学报》2022年第3期88-97,共10页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.51874264,52076200)。

摘　　要：分析了基于彩色光照的粒子图像测速算法中示踪粒子的成像原理,并根据实际流场中的应用环境以及彩色粒子图像测速算法的实验条件,采用一套由白色光源和波长线性变化的滤波片组成的照明系统,为粒子场提供不同深度、相同光强的彩色体积光照明。根据针孔相机模型和其对应的点扩散函数,建立示踪粒子的三维成像模型,得到在彩色体积光照射下流场中的粒子在彩色相机上的模拟图像。结合朗肯涡流模型生成的三维速度场得到不同时刻下的模拟粒子图像。采用彩虹粒子图像测速算法对不同密度的粒子在不同速度的朗肯涡流场下的模拟图像进行粒子分布场和粒子速度场的重建分析,与真实值对比,证明该方法生成的模拟粒子图像可以为基于彩色光照粒子图像测速算法的研究提供支撑。Fluids are very common in nature and engineering.Research in engineering fields such as fluid mechanics and aerodynamics is closely related to fluid measurement.Measuring and analyzing the motion state of fluids is a key issue in the field of fluids.The particle image velocimetry method developed in the1880s is a transient,multipoint,noncontact hydrodynamic velocimetry method.It can accurately measure the transient flow field in the plane without disturbing the fluid.This paper analyzes the imaging principle of tracer particles in the particle image velocimetry algorithm based on color illumination.According to the application environment in the actual flow field and the experimental conditions of the color particle image velocity measurement algorithm,a set of lighting systems consisting of a white light source and a filter with linearly changing wavelength is adopted to provide the particle field with color volume illumination of different depths and the same light intensity.Particles of different depths in the fluid that reflect the light of the corresponding wavelength are modeled as narrow band point light sources with different wavelengths.To obtain the accurate position of each particle imaging on the CCD,namely,the spectral distribution of the particle field,the camera pinhole imaging model is established to analyze and simulate the optical path of particle imaging.When the light reflected by particles passes through the pinhole model of the camera,imaging of particles on a CCD sensor can be achieved.First,the imaging diameter of particles is calculated by the Airy spot diameter and the real diameter of particles.Second,the normalized intensity matrix of the discrete image is obtained by the weight function of the particle intensity distribution because the strength distribution of particles should satisfy a two-dimensional Gaussian distribution.Finally,the particle’s imaging diameter and intensity are combined to acquire the particle’s point spread function.The threedimensional imaging model of trace

关 键 词：粒子图像测速 针孔成像 点扩散函数 彩色光照 朗肯涡流 

分 类 号：O351[理学—流体力学]