【作者】 谢小燕；

【导师】 刘旭；

【作者基本信息】 浙江大学 ， 光学工程， 2009， 博士

【摘要】 体显示是目前最为可行的真三维显示技术之一。随着二维显示及其相关产业发展的日趋完美,越来越多关注的目光聚焦在实现真实空间的三维显示技术上。近十年来国际上研制出了一系列基于各种原理的体显示系统,但由于实现上的巨大困难,这些系统大多数只能实现小空间内的单色显示,且分辨率不高,只能显示简单的静态图像。有鉴于此,本课题组在已有的研究基础上建立了高清晰度的彩色LED体显示系统,希望能在显示空间尺寸、图像色彩、分辨率、实时动态显示等方面有较大的突破,为真三维显示技术发展上新一个台阶提供前瞻性的实践经验和理论依据。本文围绕高清晰度彩色LED体显示系统软硬件的设计及实现展开,包括体素数据的生成及仿真,断点光纤实现海量数据的高速无线传输、增量传输实现大场景的动态显示、FPGA高速驱动电路等设想的提出,小间隙、大尺寸、高分辨率的彩色LED显示屏的设计及实现,机械设计上的优化等。所建成系统的显示空间是目前国际上已有系统中最大之一。针对LED体显示的体素形状、大小及分布特点,提出了适合本系统的直线段体素化算法:扫描映射法。在考虑LED尺寸的情况下,对LED阵列进行行和列方向上的扫描,从而获得体素数据。仿真结果及数据分析表明该算法是有效的。建立了彩色体素数据的生成及仿真软件,体素数据的颜色信息可在该平台上获得,同时通过软件设定不同的屏幕分辨率、二维截面数,比较这些情况下同一模型的仿真效果,可为确定合理的硬件参数服务。对于三维数据源被体素化后,体素点的位置偏差引起的再现三维图像的纹理失真现象,提出了基于人眼视觉特性的纹理图分区评价方法,综合体素点的位置偏差、纹理图像的感兴趣区域划分、体素点相对背景的灰度值三个因素建立了再现三维图像的纹理失真评价方程。运用此方程对三维模型中不同灰度分布的纹理图失真进行了评价,并给出了仿真图加以印证。对于纹理失真较严重的情况,通过改进体素化算法进行了修正。针对至今关于体显示的光学性能检测及显示中存在的问题等方面的研究仍近于空白的情况,本文对彩色LED体显示系统在旋转过程中的亮度及色均匀性等进行了检测及定量分析,并对显示中的死区问题作了详细分析及探讨。对于LED体显示中的消隐问题,提出了屏幕前加挡板的方案并通过实验初步验证了可行性。更多还原

【Abstract】 Volumetric three-dimensional (3D) display technique is a feasible way to realize true 3D display which displays images in an actual 3D space, with most characteristics similar to real-world objects. Nowadays with the mature development of two dimensional (2D) display and relative industry, more and more people focus on developing true 3D display technique. Some 3D display prototype systems have been built in the world recent years. However, due to many technical difficulties, most of the systems have poor performance: small display space, low resolution, only monochromatic and static display, etc. Therefore, we tried to develop a high resolution multi-color volumetric display system based on 2D rotating LED panel. It is a system with excellent performance, which provides large display space, multi-color, high resolution and real-time dynamic 3D display. Now it has been successfully completed.In this paper, implementation of software and hardware of the system was presented, including the generation and simulation of the voxel data, high-speed wireless transmission of the massive data, realization of dynamic display for large 3D scene, design of the high-speed drive circuit, realization of the small pitch, large size and high density multi-color LED panel, optimization of the mechanical system, etc. The display space of the system is the largest one in 3D display field in the world up to now.Proper voxelization algorithm namely scan mapping method for line voxelization was presented, which scanned LED array in both row and column directions according to the voxel’ s shape, size and distribution. Both simulation results and numerical analysis show that the algorithm is effective. Generation and simulation of voxel data with multi-color for this system was built, which generated color information for voxels and simulated them on PC screen. Different simulation results for the same original model under different LED panel resolution or 2D slice number per rotation were given and compared, which could specify proper hardware parameters.Evaluation of texture distortion due to voxels’ position deviations caused in voxelization was proposed, based on human visual system and texture detail distribution. The merit function of texture distortion was set-up, considering voxel’ s position deviation, distribution of details in textures and voxel’s relative gray scale. 3D Models with textures having different gray scale distribution were built and texture distortion of them was evaluated by the merit function. Numerical analysis and simulating results were also given. The voxelization algorithm was improved for the type of textures in which distortion was serious.Up to now many studies have been done on the establishment of 3D display systems. However, none of them concerns about the testing of optical performance of 3D display systems, evaluation of 3D images and the problems of 3D display. Hence this paper presented studies on the brightness uniformity and chroma uniformity of 3D display space, both accurate testing and numerical analysis were given. The dead zone of 3D images displayed by LED volumetric display system was discussed and investigated in detail. Moreover, experiments were done to show that LED volumetric display was capable of occlusion utilizing lenticular or parallax-barrier.更多还原