三维物体的计算全息图快速生成算法及显示研究

发布时间：2018-05-30 05:32

本文选题：计算全息 + 全息三维显示　；参考：《昆明理工大学》2017年硕士论文

【摘要】：全息三维显示技术能够再现三维物体光波前分布的全部信息,被认为是最具发展前景的真三维显示技术。基于空间光调制器的全息三维显示技术,可以实现实时动态真彩色三维显示的效果,因此吸引了国内外各个高校和研究机构的广泛关注。目前,计算全息三维显示技术的发展主要受制于显示器件分辨率低、全息图计算量大等问题,如何提高显示设备的分辨率以及获得快速生成计算全息图的算法和系统是目前还需研究的问题。本文主要开展基于液晶空间光调制器的计算全息图快速生成算法的研究,研究内容简述如下:首先综述了三维显示技术并分析了三维显示技术的现状与发展。介绍基于标量衍射计算的相关理论知识,并对光波通过光学系统的波前重建公式的修正进行了分析。当光波在非单一介质中传播时,给出了将记录距离等效为介质中传播距离的方法。结果表明,计算光波在介质中传播的等效距离,并采用等效距离对数字全息图进行波前重建的结果与采用柯林斯公式重建的结果是一致的。其次,简要的说明了空间光调制器的基本性能及相位调制原理。对空间光调制器的脉冲响应进行了简单推导,导出基于空间光调制器的全息三维显示系统的焦深。采用基于迭代的菲涅尔衍射积分逆运算重建算法实现相位全息图的生成,并进行了模拟重建实验和光学实验重建。最后,对传统点源法的基本原理及改进算法进行了介绍,重点研究了波前记录算法,并进行了相关的模拟和实验。在此基础上,根据课题组之前的研究内容,给出基于焦深分层的光源变换算法,考虑环境光照明和物体隐藏面的消除,实现三维物体的计算全息图快速生成及显示,相对于传统的点源算法,光源变换算法生成计算全息图的速度提高了两个数量级左右,同时,由于在投影平面到全息面采用快速傅里叶变换算法,根据物平面和全息面的尺寸关系,能够实现大尺寸的三维物体重建。在焦深范围内,采用光源变换算法对简单的彩色三维物体进行了模拟重建,可为后期实现复杂彩色三维物体全息显示打下基础。搭建了基于空间光调制器的全息三维显示系统,实现了三维物体的光电再现,取得了较好的实验结果。
[Abstract]:The holographic 3D display technology can reproduce all the information of the 3D object optical wavefront distribution and is considered to be the most promising true 3D display technology. The holographic 3D display technology based on spatial light modulator can realize the effect of real-time dynamic true color 3D display, so it has attracted wide attention of universities and research institutions at home and abroad. At present, the development of CGH 3D display technology is mainly restricted by the low resolution of display devices and the large amount of calculation of hologram. How to improve the resolution of display equipment and how to obtain the algorithm and system for fast generation of CGH are still problems to be studied. In this paper, the fast generation algorithm of CGH based on liquid crystal spatial light modulator is studied. The research contents are summarized as follows: firstly, the 3D display technology is reviewed, and the present situation and development of 3D display technology are analyzed. The related theoretical knowledge based on scalar diffraction calculation is introduced, and the correction of wavefront reconstruction formula of light wave passing through optical system is analyzed. When the light wave propagates in a non-single medium, a method of equating the recording distance to the propagation distance in the medium is given. The results show that the calculation of the equivalent distance of light wave propagation in the medium and the reconstruction of digital holograms by using the equivalent distance are consistent with the results of the reconstruction using Collins formula. Secondly, the basic performance of spatial light modulator and the principle of phase modulation are briefly explained. The pulse response of spatial light modulator is deduced and the focal depth of holographic 3D display system based on spatial light modulator is derived. An iterative Fresnel diffraction integral inverse reconstruction algorithm is used to generate the phase hologram, and simulated reconstruction experiments and optical experimental reconstruction are carried out. Finally, the basic principle and the improved algorithm of the traditional point source method are introduced, and the wavefront recording algorithm is studied, and the simulation and experiment are carried out. On this basis, according to the previous research contents of the research group, a light source transformation algorithm based on the layer of focal depth is presented, which takes into account the illumination of the environment and the elimination of the hidden surface of the object to realize the fast generation and display of the 3D object's CGH. Compared with the traditional point source algorithm, the speed of generating CGH by the light source transform algorithm is increased by about two orders of magnitude. At the same time, the fast Fourier transform algorithm is used in the projection plane to the holographic plane. According to the dimension relation between the object plane and the holographic plane, the large-scale three-dimensional object reconstruction can be realized. In the range of focal depth, the light source transform algorithm is used to simulate and reconstruct the simple color 3D object, which can lay the foundation for the realization of the complex color 3D object holographic display in the later stage. A holographic 3D display system based on spatial light modulator is built, and the photo-electric reconstruction of 3D object is realized, and good experimental results are obtained.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O438.1;TP391.41

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