【作者】 马飞；

【导师】 李保生；

【作者基本信息】 合肥工业大学 ， 测试计量技术及仪器， 2016， 硕士

【摘要】 在人工影响天气方面,对云滴粒子的探测对于人工有效的影响天气提供了重要参考。由于云层的结构有许多复杂的因素,云种散播区域难以准确确定。在人工影响天气的过程中,精准的获得云层的内部分布具有十分重要的意义。数字全息技术是用新型的光电CCD探测器代替传统的光学干板作为记录全息图的材料的一种新型的全息成像技术。其通过使用计算机来模拟光衍射过程,从而得到被测量物场的波前分布情况,最终实现了整个全息过程的数字化,包括记录、存储、传输和再现。随着现代高分辨率CCD及计算机技术的高速发展,数字全息技术因其能够实现对三维粒子场的测量以及细节参数的获取,而被广泛应用于粒子测量。本文采用同轴数字全息方式对实验室中仿真的粒子进行记录,获得粒子的数字全息图,并且通过计算处理获得群体粒子的重要参数,如粒子三维坐标空间分布,及特性参数,包括形状、粒径、椭圆度。本文研究了传统全息技术和数字全息技术的记录和再现理论,对光学全息的记录过程的数学表达分别从解析解和数值解两个方面进行了分析,对两种不同的全息再现算法进行了比较,对测量粒子场所用的同轴数字全息的平面波记录系统进行了研究。经过对图像数据的预处理,达到降低图像噪声的目的。研究多种粒子判焦方法,其中运用灰度合成法对灰度进行提取,来实现粒子三维坐标的测量；运用灰度梯度法对梯度进行提取,获取粒子的边缘来测量粒子三维坐标。在测量过程中,均需要使用阂值对判焦方法中的粒子进行提取。最终对所提取到的粒子的粒径进行估算。对实验系统进行设计,完成实验系统的搭建,包括各部分之间的软件连接,对自制铝屑粒子场和水滴进行全息图拍摄,运用卷积再现算法、灰度合成判焦等对所得图像数据进行处理并进行相应分析。本论文最终验证了同轴数字全息装置应用于云层参数测量的可行性,并完成了实验系统的搭建,完成了实验中的仿真粒子测量。更多还原

【Abstract】 In terms of weather modification, the cloud droplets particle detection is one of the important measures. It provides important information for artificial weather modification effectively. Due to the complexity of structure of clouds, cloud seeding area is difficult to determine accurately. In the process of weather modification, obtaining accurately the internal distribution of clouds is greatly significance.Digital holography is a new kind of holographic imaging technology. It uses the new type of optical CCD detector to instead of the traditional optical dry plate as the material of recording hologram. It is through the use of computer to simulate the process of light diffraction, to obtain the distribution of the field of holography. Finally, it can achieve the whole process of digital hologram, including recording, storage, transmission and reconstruction. With the rapid development of modern high resolution CCD and computer technology, digital holographic technology is widely used in the particle measure, because it can realize to the measurement of three-dimensional particle field and obtain detail parameters.This article adopts the in-line digital holographic method to records of laboratory simulation of particles, and obtains the particle digital hologram. In the end, some parameters of the groups of particles were obtained by the application of computing. Such as, the three-dimensional distribution of particle, and monomer characteristic parameters, including shape, particle size, ovality.This paper studies the traditional holography and digital holography recording and reproduction theory, analyzes the math expression of the optical holographic recording process respectively from two aspects of analytical solution and numerical solution, compares the two different kinds of holographic representation algorithm, studies the plane wave recording in-line digital hologram system to measure particle.After preprocessing of the image data, the image noise can been reduced. It studies a variety of method of particles found focus location, which using gray-scale synthesis method to extract for gray level, to achieve three-dimensional distribution of particles. All measurements in the process of measurement need to use the threshold to extract particles in the particles found. Finally, extracted the particle size is estimated.Designing experiment system, and completing the construction of the experimental system. Including the holography for homemade aluminum dust particles and water droplets, using convolution representation algorithm, gray-scale synthesis sentenced to focus on the image data processing and the corresponding analysis.This paper proves the feasibility of in-line digital holographic device that is applied to the clouds parameter measurement. It completed the construction of the experimental system, and the measurement of particle of the experimental simulation.更多还原