【作者】 颜才杰；

【导师】 刘旭； 李海峰；

【作者基本信息】 浙江大学 ， 光学工程， 2011， 博士

【摘要】 多视图三维显示技术是目前研究最为热门的三维显示技术。随着多视图三维显示技术的发展,人们提出了一种可周视的全景视场三维显示。这是三维显示的一个全新研究方向,它在水平方向具有众多视角数,可以覆盖三维图像水平方向360°的视场。与体三维显示相比,它具有很好的视觉遮挡效果,是一种更符合人们视觉习惯的三维显示技术。本文从现有全景视场三维显示系统出发,提出了基于柱体图像空间的全景视场三维显示原理,该理论指出了各种具有水平视差的全景视场三维显示系统显示的图像空间为柱体图像空间,其空间的大小由最边缘显示像素位置和最大扫描角决定。现有的全景视场三维显示有柱面定向式、平面平行定向式和平面会聚定向式三种定向屏。详细分析了三种定向屏的发光特性和显示原理。通过投影视图与显示像素映射关系的研究,对显示图像畸变矫正和图像生成方法的研究起到了指导作用,同时有利于理解三维图像在不同深度平面上不同体空间分辨率的分布。我们研究了三种定向屏的柱体图像空间内的虚体素空间分布,从双眼的体视条件、投影视图分辨率、虚体素分辨率三个方面研究了全景视场三维显示对一周可视视图数要求。我们详细讨论了一种基于LED柱面屏的全景视场三维显示系统。在显示原理、图像生成、系统参数设计、电路控制设计四个方面做了详细的分析。全景视场三维显示原理最主要的就是控制每个像素的发光方向和发光角度,计算出了每个视角的中心发光方向和发光角度,推导出了可见视图对应显示像素的视角分布。提出了一种基于360°视图的全景视场三维显示图像生成方法。通过最大扫描角、转速、周像素数的分析,我们设计了一组较为合理的系统参数,通过模拟仿真进一步验证了设计参数的合理性。系统电路设计主要有高速寻址电路和同步显示调试两个方面技术难点。在同步显示调试方面,由于LED显示板的不均匀分布和狭缝光栅的不均匀周期,我们提出了像素同步和视角同步两步调试方法。通过这两种方法的调试,成功实现了三维场景的彩色三维图像显示。随着三维显示技术研究的继续深入,评价再现三维图像的显示性能将会成为人们下一步研究的主题。我们主要研究了显示图像的几何特性、亮度特性、色度特性、空间特性。设计了一系列测试图像,分别在实验中探测各种特性的性能指标。再现三维图像的评价,不仅能给出本系统的显示性能指标,实现在不同三维显示系统之间的比较,同时为开发新一代三维显示器件制定了显示性能标准。最后详细分析全景视场三维显示系统的发展前景,通过模拟视角数对三维图像体空间分辨率的影响,和根据LED的显示频率、海量数据的传输、LED阵列的排布密度等三方面的技术瓶颈给出了一组高清晰三维图像的全景视场三维显示的系统参数,为今后全景视场三维显示的发展提供了研究方向。更多还原

【Abstract】 Multi-view three-dimensional (3D) display technique is one of the most popular three-dimensional displays. Nowadays, with the development of multi-view display, omni-directional three-dimensional display is presented, which is a new research direction of 3D display. It has super multi-views in horizontal direction and can display 3D images with high resolution. Compared with volumetric display, it has a good occlusion-capable effect, which is a 3D display technique in line with the human vision.In this paper, the theory of omni-directional 3D display with cylindrical image space is presented from some existing omnidirectional 3D displays. This theory indicates that the image space of all omni-directional 3D displays with only horizontal parallax is cylindrical space, the size of which is dependent on the most marginal pixel location and the maximum scanning angle. The existing omni-directional 3D displays mainly contains cylinder direction-selective type, plane parallel direction-selective type and plane converge direction-selective type. With these three kinds of 3D displays, the optical characteristic of direction-selective screens and their display principle are analyzed in detail. The study on the mapping relation between the projecting view and pixels directs the study on the image rendering algorithm and distortion correction. At the same time, the study is also helpful to understand the 3D image distribution in different depth with different spatial resolution. The virtual voxel distribution in the cylindrical space is investigated. The requirement to the number of images all round is studied from stereoscopic vision, projecting view resolution and virtual voxel spatial resolution.The color omnidirectional 3D display system based on cylindrical LED screen is discussed in detail. The display principle, image rendering, system parameter design and simulation, and circuit control design are analyzed. The key to this display principle is to control the each pixel’s light emitting direction and angle. The center light direction and emitting angle in each view and the pixels’view distribution in the observed view are calculated. An image rendering method based on omni-directional views of a 3D scene is proposed. Through analysis of maximum scanning angle, rotation speed and pixels’number in one revolution, a set of reasonable system parameters is designed, which has been validated via simulation. The circuit design mainly has two technical difficulties:high-speed addressing and display synchronicity. In debugging display synchronicity, owing to the LED asymmetrical distribution and parallax barrier’s pitch ununiformity, the debugging method has two steps:pixel synchronization and view synchronization. With this debugging method, color 3D display is completed successfully.With the development of 3D display, display image evaluation is gradually focused on. We have investigated the geometry, bright, color, space characteristic of display 3D image with quantitative indeces. We have designed a series of test imag es for these characteristic, and detect all characteristics in experiment.3D image evaluation can show performance of 3D display system, which can be used for comparing among different 3D display systems, but also give higher display performance-for next-generation 3D display.At last, we have discussed the development of the omnidirectional-view 3D display. The relation between view number and 3D image resolution is investigated. We obtain system parameters of omnidirectional-view 3D display with better 3D image according the LED display frequence, massive data transmission, and LED arrangement pitch, which shows us a research direction of future development.更多还原