Theoretical And Experimental Research Of Interferometric Imaging With Transparent Particles

Particle exists widely in spray field,and the measurement of particle information has important significance to study the properties of the particle.Interferometric particle imaging?IPI?is a technique for measuring the particles.It is on the basis that the interference image is formed on the defocused image and the in-focus image is formed on the focused image by the scattered light which includes the reflected light from the particle surface and internal refracted light.Based on the transmission matrix,the defocused and focused light field of the spherical and ellipsoidal particles are studied theoretically and experimentally;the influence of the sample pool layout on the IPI system is researched;and the theoretical analysis and the experimental research of the sampling volume and the concentration in defocused IPI are carried out.Main work of this paper:1.The interferometric imaging measurements of the spherical and ellipsoidal particles are analyzed theoretically.Based on the transmission matrix,the scattered light field distribution of the particle in IPI system is studied.According to the geometrical optics,the positions of exit points on the surface of spherical particles and ellipsoidal particles at certain scattering angles have been analyzed and the focused and defocused images have also been analyzed.2.For the IPI system,the calculation method of the image distance,object distance and the size of the out-of-focus interferogram are given.The influence of the placement of the sample pool on the system is analyzed theoretically and experimentally.The Zemax is also used to simulate and analyze the images of the particles.3.The defocused IPI can be used to measure the particle concentration.Based on geometrical optics,the method of calculating the sampling volume of the out-of-focus IPI system is studied.Whether the interferogram size is within the theoretical size range[?37?_pix2,?37?_pix1]is used to judge the particles in the sampling volume and provide the information for calculating the particle concentration.The experimental results of the particles with different sizes and concentrations verify the feasibility of this method.4.The experiments with spherical and ellipsoidal particles are conducted.The ellipsoidal particles are prepared with standard particles as raw materials.The experiments with spherical and ellipsoidal particles have been done by the use of IPI system.In the practical IPI system,two CCDs are placed behind the imaging lens and are used to receive the in-focus or out-of-focus images of particles simultaneously.