导　　师： 桑新柱

学科专业： 0809

授予学位： 硕士

作　　者： ;

机构地区： 北京邮电大学

摘　　要： 成像技术的重要发展趋势之一就是真实地再现3D场景,而全息显示的特征就是可以在空间中再现真实的3D物体。在该技术目前的研究情况、发展现状以及存在的问题分析的基础上,本论文进行了相关的研究工作,主要工作内容和创新点如下： 第一,通过分析计算全息图的制作和再现流程,详细地阐述了计算全息的理论基础。重点介绍了菲涅尔计算全息和傅里叶变换计算全息技术,并且推导出了快速简便的编程算法。具体介绍了两种最典型的编码技术,即罗曼Ⅲ型编码和博奇编码,分析了这两种编码方式的优缺点以及适用场合,并且使用计算机进行仿真验证。 第二,对典型的三维物体全息图的计算方法进行了研究,并分析了各种方法的适用范围,针对多视角投影法和层析法进行了仿真验证。在现实世界中,物体都是彩色的,可以通过分解成3个通道分别进行处理,最后再融合到一起。因此,本文采用“等距方法”对彩色物体的全息图计算和数值再现进行研究,并通过仿真验证了其理论的可行性。 第三,在数字全息的记录和再现的过程中,不可避免地受到各种因素的影响。其中最主要的是散斑噪声,这会降低再现图像的分辨率。本文提出了一种结合边缘提取算法和小波变换的去噪方法,实验结果表明可以在保留图像细节信息的前提下,有效地滤除散斑噪声。 第四,采用理论分析与实验验证相结合的方法,通过分析合成孔径数字全息的记录和再现的基本原理,验证了此技术能够有效的提高再现像的质量。采用基于灰度图像相关性的图像匹配技术,确保了各个子全息图准确拼接。 最后,对上述工作进行了总结,取得了一些成果但是也存在了不足之处,同时对未来工作进行了下一步的规划。 One of the important trends of display technology is to display real-existing three-dimensional /(3D/) images. More and more attentions are now paid on holographic display because of its capability of reconstructing real-existing3D images in the space. Based on the current research status and the existing problems, some related research work is carried out. By combing the process of the production and reconstruction of computer-generated holography /(CGH/), the theory basis is expounded. Focus on Fresnel and Fourier transform CGH technology, a faster and easier programming algorithm is derived. Two of the most typical coding technology is introduced in detail, the Roman type Ⅲ coding and Burch coding, whose advantages and disadvantages are analyzed in the paper and proven by the computer. Typical calculation methods of3D objects are described, especially for the perspective projection and chromatography methods. In the real world, the object is color. It can be broken down into three channels to process respectively, and then mixed together. Therefore, the "isometric method" is adopted for true color hologram calculation and numerical representation of an object, and the feasibility of the theory is verified by computer simulation. Digital holography is a kind of coherent imaging method and inevitably affected by many factors in the process of recording. One of dominant problems is the speckle noise, which is essentially nonlinear multiplicative noise related to signals. Due to the noise pollution, the low resolution of image reconstructed is caused. A new solution for suppressing speckle noise in digital hologram is presented, which combines Canny filtering with wavelet transform. Experimental results show this approach can not only effectively eliminate speckle noise, but also retain useful signals and edge information simultaneously. To effectively improve the quality of reconstructed image, synthetic aperture digital hologram is proposed in the paper. Image matching technology based on correlation of gray image, can solve the problem of the accurate and each hologram splicing. Finally, the above work is summarized and made some achievements. At the same time, the next step of future work is planned.

关 键 词： 数字全息 计算全息 三维显示 去噪 合成孔径

分 类 号： [TP391.41 TN27]

领　　域： [自动化与计算机技术] [自动化与计算机技术] [电子电信]