数字全息的高精度检测技术研究

发布时间：2018-03-29 01:03

本文选题：数字全息　切入点：记录光路　出处：《西安工业大学》2015年硕士论文

【摘要】：数字全息是现代光学检测技术的重要手段之一,它用CCD代替了传统全息的记录干板,实现了全息记录的数字化,再辅助以计算机通过一定的算法便可以再现所记录的物体。按照记录光路的不同系统一般有两种形式,分别是同轴数字全息和离轴数字全息。同轴全息需要采集多幅全息图或者借助于相移器件来使物体的再现像与共轭像分离,而离轴全息只需要调整光路结构就可以使他们分开,具有更广泛的研究和应用价值。同时数字全息是一种实时无损的检测方法,而且可以三维再现物体的形貌,因此,展开对数字全息检测技术的研究十分必要。本文主要对其检测的方法进行研究,并使之达到较高的精度。主要内容有：首先,对数字全息检测的基本理论进行了分析,针对目前数字全息普遍存在的再现像的精度差、相位信息的准确获取困难、零级像和共轭像干扰等的问题,本文确定了以无预放大离轴数字全息系统为基础进行检测的研究。通过理论分析,确定了记录光路影响再现结果的关键因素,对记录距离和物参夹角进行了理论上的分析,并且通过MATLAB模拟数字全息的记录和再现的过程,通过调整记录和再现的实验参数,验证了这些因素对全息再现结果的影响；其次,通过理论上的计算和分析,选择器件搭建了实验平台,通过调试实验的记录系统,采集到了高质量的全息图。最后,对再现算法进行了理论分析,并且通过计算机编写MATLAB程序,对采集到的全息图通过频谱滤波的方法进行了预处理,消除了零级像和共轭像的频谱,再通过角谱法的编写,完成了对物体的高精度三维重建。对提取的相位图进行了解包裹和畸变消除,从而得到了真实的相位信息,并且获得了物体的表面形貌；通过对同一样品的对比检测,验证了该系统和算法的准确性；通过对不同的样品进行检测,证明其具有普遍的适用性。
[Abstract]:Digital holography is one of the important means of modern optical inspection technology. It uses CCD instead of the traditional holographic recording board, and realizes the digitization of holographic recording. Then the computer can reproduce the recorded object through a certain algorithm. According to the different systems of recording the optical path, there are generally two forms. They are coaxial digital holography and off-axis digital holography. Coaxial holography requires collecting multiple holograms or isolating objects from conjugate images by means of phase-shifting devices, while off-axis holography can separate them by simply adjusting the structure of the optical path. At the same time, digital holography is a real time nondestructive detection method, and it can reproduce the appearance of objects in three dimensions. It is necessary to carry out the research on digital holographic detection technology. This paper mainly studies the methods of digital holographic detection and makes it achieve higher accuracy. The main contents are as follows: firstly, the basic theory of digital holographic detection is analyzed. In view of the problems such as poor precision of reconstructed image, difficulty in obtaining phase information, interference of zero-order image and conjugate image, etc. In this paper, the research on the detection of off-axis digital holographic system without preamplifier is determined. Through theoretical analysis, the key factors influencing the reappearance result of recording optical path are determined, and the recording distance and the angle of object parameter are analyzed theoretically. And through the MATLAB analog digital holography recording and reproducing process, by adjusting the experimental parameters of recording and reproducing, the effects of these factors on the holographic reconstruction results are verified. Secondly, through theoretical calculation and analysis, The high quality hologram is collected by debugging the recording system of the experiment. Finally, the reconstruction algorithm is analyzed theoretically, and the MATLAB program is written by computer. The collected holograms are preprocessed by the method of spectrum filtering to eliminate the spectrum of zero-order images and conjugate images, and then the angular spectrum method is used to compile them. The high precision 3D reconstruction of the object is completed. The extracted phase image is understood and the distortion is eliminated, the real phase information is obtained, and the surface morphology of the object is obtained. The accuracy of the system and the algorithm is verified, and the universal applicability of the system is proved by the detection of different samples.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN26

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