基于数字微镜和旋转扫描技术的体三维显示器

研究了一种基于旋转体扫描方案的体三维显示系统,利用数字微镜设备(DMD)作为空间光调制器,将三维场景经离散化后得到的一系列二维切片轮流投影到高速旋转的屏幕上,基于视觉暂留效应,按时序变换的二维切片图像可被人眼融合并感知为连续完整的三维图像.试制了原理样机,实现了三维图像以24 Hz的刷新频率在体积为Φ200 mm×100 mm的柱体空间内的显示,可以任意选择视点直接观看,验证了设计方案的可行性.     

真三维立体显示技术中体扫描技术的图像引擎研究

真三维立体显示技术是近年来新兴的三维显示技术。在三维立体空间对物体成像,突破了平面显示的禁锢。立体显示技术使用了很多方法,如静态体成像技术和体扫描技术。本文研究了用于显示动态体的体扫描技术的图像引擎的一些特性,使用一个基本的配备了无源发射表面的平移运动的体扫描系统的图像引擎。详细研究了坐标系统的转换,处理图像数据的过程,体素排序等。为真三维立体显示技术的进一步研究提供了必要的理论基础和重要的技术方法。     

真三维旋转显示屏体素分析及均匀化校正研究

基于人眼视觉滞留效应,采用高速旋转的平面显示屏像素瞬间发光,形成圆柱体立体空间中的体素,重建真三维立体图像显示。针对旋转体机械结构造成的体素外疏内密的特点,本文研究了体素均匀化校正处理,得到较为理想的立体三维图像显示。     

固态体积式真三维立体显示效果优化

为了优化固态体积式真三维的立体成像效果,显示出更加逼真的立体图像,对编码图像的灰度级和成像显示体的对比度进行了研究。论文从固态体积式真三维立体显示器成像原理出发,介绍了固态体积式真三维的电路系统、光学投影系统和成像显示体,在分析和研究影响立体显示效果的主要因素后提出了两种改进的方法。一种方法是通过降低图像刷新频率,提高编码图像数据位数,从而提高像素灰度等级,另一种方法是改变液晶光阀的盒厚,以此增强显示体的对比度。在真三维样机上,成功实现了32级灰度,将颜色种类从4 096种提升至32 768种,对比度相比原样机提高了1.2倍,主观感受到更加丰富的图像细节和色彩。优化效果明显,可以显示出细节更加清晰、颜色更加丰富和效果更加真实的三维立体图像。     

多屏幕三维体显示技术

现如今随着科技的进步,显示技术已不仅仅局限于二维的平面中,各种三维的显示技术层出不穷。本项目对基于多块PDLC(聚合物掺杂液晶[1])屏幕的立体显示技术进行了研究,利用了PDLC屏幕的开关特性,采用多屏幕分时显示,同步的全息投影的方法,显示出三维的图像。实验中分析了PDLC屏幕的响应特性,设计了屏幕的驱动电路的硬件、时序和波形,探讨了基于Opencv的景深提取算法。最后获得了有一定景深的三维图像。     

应用微柱透镜的自由立体前投影屏幕设计

介绍了应用微柱透镜阵列的自由立体前投影显示的原理。推导出确定自由立体前投影屏幕中微柱透镜参数的公式,详细给出了一种设计方法。根据此方法设计了一块采用微柱透镜阵列的自由立体前投影屏幕,在Lighttools中对采用此屏幕的投影系统进行仿真模拟,仿真结果显示有5个比较明显的视区,视区间隔比较连续。搭建屏幕和投影系统进行实验验证,实验结果与仿真结果一致,串扰度为7.9%,图像重合度为1.008,在观察面处立体效果显著。实验结果验证了应用微柱透镜阵列的自由立体前投影显示的可行性。与背投影的自由立体显示技术相比,自由立体前投影显示具有装调快、占用空间小、投影距离灵活可调的优点,将是未来大屏幕自由立体显示的一个重要发展方向。     

多视点三维投影显示系统

许多人都认为自动分光立体显示技术将使得家庭视觉体验朝着更自然、更逼真的方向发展.为了营造更逼真、更刺激的 VR 效果,屏幕越大越好.本文旨在详细介绍运用在 3D 显示的多视点三维投影系统.三维图像方法的原理是视差的深度暗示.采用的方法的视差不是由于使用特殊光学眼镜或者是特殊的光学头盔作为观察光学图像形成区域而引起的.实验装置系统包括暗箱组、PC 组和一个多视点三维显示器.采用了透镜、视差栅栏来制作空间多元多视角的自动分光立体显示器.使用投影仪来模拟分光图像对.这种自动分光显示屏幕的优点在于:容易按比例放大;低成本;投影仪和屏幕间不需要精确对准.本文还研究了该屏幕的制作工艺,并给出了实验结果.     

基于灰度值编码的三维轮廓数据表示方法

近年来,在线三维数字博物馆成为文物保护和资源共享的新兴手段,但是使用三维扫描技术获得的三维轮廓数据体积较大,不便于三维数字博物馆数据的实时加载与显示。针对该问题,提出了一种基于灰度值编码的三维轮廓数据表示方法。在虚拟条纹投影系统的基础上,根据虚拟照相机水平方向分辨率将灰度值编码为8位灰度图像或者8位灰度图像和二值图像,并将其作为投影图像进行投影。使用虚拟照相机对发生形变的投影图像进行拍摄,实现三维轮廓数据的图片表示。实验结果表明,与传统的三维数据格式相比,提出方法所需的数据加载及显示时间减少了98%以上,非常适合基于三维轮廓数据数字博物馆的数据实时加载与显示。     

VTK技术在雷达图像可视化中的研究与应用

利用VTK对雷达图像数据进行三维可视化研究,其中研究了表面绘制和体绘制两种绘制技术：表面绘刺用移动立方体法实现,体绘制用合成光线投影算法实现。实验高效快捷地显示了雷达二维图像,实现了雷迭四波数据的空间整体三维重建显示和x,y,z三维任意切面的雷达回波强度显示,并且可以任意方向切割、旋转、放大与平移三维图像。VTK应用于雷达图像三维可视化更为直观和全面的展现了空间回波的分布状况。     

基于光学显微镜的三维成像技术

传统研究显微样本三维结构的方法是通过在显微镜下获取其二维图像进行观察和分析的,难以准确理解样本的三维结构.因此,研究显微三维成像理论、三维定量分析技术,具有很高的实用价值和重要的学术意义,该领域的研究也是显微信息学科的研究热点之一.针对不同显微样本的三维成像与处理问题,论文以多种光学数码显微镜作为硬件平台,系统、全面地开展了基于光学显微镜的显微三维成像、处理和分析方法的研究.重点研究了聚焦深度显微三维成像、显微双目立体成像、序列显微光学切片三维成像、连续物理切片显微三维成像测量等关键技术和系统实现.聚焦深度显微三维成像方法为解决显微成像景深有限的问题,研究了各种序列显微图像空域聚焦融合算法,对优选出的改进Laplacian算子图像融合方法,提出了基于深度图去噪处理等的优化改进方案,实现了序列显微图像的有效合成,扩展了显微照相的景深.在此基础上,实现了一套基于聚焦深度的显微三维成像测量显示系统.三维成像实验:以昆虫眼睛图像序列验证三维成像方法.昆虫眼睛图像序列原始图用MOTICDMBl显微镜,4倍物镜,冷光源外照射反射光成像,包括33幅不同聚焦层面的原始图像.三维成像效果达到一定实用要求.双目立体体视显微镜三维成像为改进传统光学体视显微镜实现立体显微三维成像,根据计算机立体视觉原理,提出了一种基于光学数码体视显微镜的显微立体表面成像、测量系统方案.针对该系统特点,提出使用线性标定模型来标定立体视觉系统.为解决光学显微立体图像的匹配问题,从所研究的两种匹配算法中,优选出新序数测度匹配法.基于上述方案和算法,实现了一套基于光学数码体视显微镜的显微立体表面成像、测量软件系统.三维成像实验:以某航空材料断口表面显微三维立体成像为例验证该三维成像方法,材料断口表面显微图像采用本研究设计的双目立体摄像MOTIC K500MBGG体视显微镜,16倍物镜,冷光源外照射反射光成像,包括2幅左、右光路采集的原始图像.三维成像效果达到一定实用要求.序列光学切片显微三维成像为解决显微荧光三维成像去模糊的问题,研究实现了最近邻、线性去卷积和最大期望光学切片去模糊复原方法,分析总结了上述三种算法的性能和优缺点,给出了各算法适用的条件.在此基础上实现了一套序列显微光学切片三维成像系统.三维成像实验:为说明光学切片三维去模糊效果,以Confocal获取的显微荧光细胞三维图像为例,本序列图像由MOTIC集团提供,共16层图像,各层图像上有一些模糊效果,经EM去模糊算法50次迭代,一定程度上去除了模糊效果,然后用体可视化方法显示.显微物理切片三维成像研究了生物组织序列切片图像的三维重建和测量方法,根据连续组织切片的特点,提出用上、下层切片图像间存在的对应结构特征部分作为控制点,采用2次多项式进行几何校正、配准.对当今国内、外体视学界广泛认同的三维粒子测量计数方法一双层切片法(Disector)原理进行了分析,提出在计算机图像分析系统上,设计实现自动双层切片体视测量和三维成像方法.三维成像实验:以大鼠肝门部胆管微血管切片图像序列为例验证该三维成像方法.本序列图像选自与解放军总医院肝胆外科一同合作的"大鼠肝门部胆管微血管的三维重建"实验,总共有16幅经空间配准后的不阿层面的大鼠肝门部胆管微血管厚切片序列图像.三维成像效果满足医学研究需要.     

基于计算全息技术的彩色CT真三维可视化

不同于现有的用计算机软件合成的CT 图像的伪 三维可视化,本文提出了一种基于计算全息技术的彩色CT 图像的真三维可视化技术。首先,利用计算全息技术对彩色CT图像进行三维重建,将一组 彩色CT图像的空间 二维信息融合成三维信息,并以计算全息图(CGH)的形式进行保存;然后,设计了彩色CT图 像光电再现与三维显示系 统,以液晶空间光调制器(LC-SLM)作为CGH的显示载体,通过计算机同时输入 3幅CGH,通过光电再现获得 三原色三维再现像,利用合色棱镜将三原色再现像合成为彩色图像,用雾屏作为彩色三维再 现像的显示载体,获 得彩色真三维CT图像。在全息图的计算过程中,基于CT图像的二维属性,采用了快速傅里 叶变换(FFT)算法,大大加快了计算速度。给出了理论分析与实验结果。     

3-Deep: new displays render images you can almost reach out and touch

Research continues to develop volumetric displays that render images in a 3D space rather than on a flat screen, focusing on two main technological approaches to displaying solid images electronically. The first approach is known as swept volume, which uses a high definition projector or an array of lasers to bounce images off a screen that rotates so fast that the human eye perceives only a 3D image floating in space. The other approach involves an all solid-state design that uses a projector behind a stack of 20 liquid-crystal screens to create one solid image from a rapidly projected series of images. All these systems create 3D images that require no special eyewear, produce no eye fatigue or headaches, and are visible over a wide field of view from several meters away by many people. If all goes well, economies of scale could bring prices down to a point where all sorts of intriguing applications become possible.     

基于HVS的LED显示屏亮度均匀性评估方法

针对全彩LED显示屏的特点,提出了一种基于人眼视觉特性(HVS)的评价显示屏亮度均匀性的新方法,并通过实验进行了验证。该方法通过CCD图像传感器获取LED图像,并将图像划分成尺寸相等的子区域,计算出各子区域基于HVS的亮度特征因子、纹理细节特征因子和空间位置特征因子,用3个因子的特征融合作为每一区域的评估参数,用全屏各区域参数的离散程度值作为均匀性评价指标,客观准确地给出评估分析结果。实验证明,该方法与人的主观评价结果基本符合,提高了显示屏亮度均匀性主观评价与客观评价的一致性。     

高分辨率多视点动态全息3D显示

提出了一种高分辨率多视点动态全息3D显示方法,观看视点位置变化时,观看者能够看到连续变化的3D效果。在进行全息图计算时,首先根据针孔阵列投影模型,渲染3D动画中每一帧3D模型的光场图像序列;然后从已渲染的多组光场图像序列中抽取对应视角信息的光场图像进行融合,得到融合后的动态光场图像序列;在进行全息图编码时,以动态光场图像序列中的一帧图像作为物光振幅,以来自于针孔的发散球面波的相位作为物光相位,引入平面参考光进行编码,得到一个单元全息图。由于每个单元全息图的计算是相互独立的,因此在计算过程中使用并行加速计算,实现了尺寸为32 mm×32 mm、分辨率为100000 pixel×100000 pixel的高分辨率全息图,其光场图像融合和全息编码的时间仅需27 min。光学再现结果证明了该方法的可行性。所提出的高分辨率多视点动态全息3D显示方法在全息包装和3D广告等领域具有广泛的应用前景。     

A portable image overlay projection device for computer-aided open liver surgery

Image overlay projection is a form of augmented reality that allows surgeons to view underlying anatomical structures directly on the patient surface. It improves intuitiveness of computer-aided surgery by removing the need for sight diversion between the patient and a display screen and has been reported to assist in 3-D understanding of anatomical structures and the identification of target and critical structures. Challenges in the development of image overlay technologies for surgery remain in the projection setup. Calibration, patient registration, view direction, and projection obstruction remain unsolved limitations to image overlay techniques. In this paper, we propose a novel, portable, and handheld-navigated image overlay device based on miniature laser projection technology that allows images of 3-D patient-specific models to be projected directly onto the organ surface intraoperatively without the need for intrusive hardware around the surgical site. The device can be integrated into a navigation system, thereby exploiting existing patient registration and model generation solutions. The position of the device is tracked by the navigation system's position sensor and used to project geometrically correct images from any position within the workspace of the navigation system. The projector was calibrated using modified camera calibration techniques and images for projection are rendered using a virtual camera defined by the projectors extrinsic parameters. Verification of the device's projection accuracy concluded a mean projection error of 1.3 mm. Visibility testing of the projection performed on pig liver tissue found the device suitable for the display of anatomical structures on the organ surface. The feasibility of use within the surgical workflow was assessed during open liver surgery. We show that the device could be quickly and unobtrusively deployed within the sterile environment.     

Three-dimensional color display by projection-type composite holography

A new method of projection-type composite holography for displaying three-dimensional (3-D) color information has been developed. The basic concept and the results of the experiments are described. A model 3-D color display system for storing several kinds of colored cinematic information is presented as a practical application of the method. This method constructs the 3-D color image by synthesizing the reconstructed images which are projected on the unilaterally direction-selective screen from several holograms. The 3-D color information is recorded as 3N holograms on a roll film arranged in an arc, the center of which is located on the screen. To reconstruct the 3-D color information three kinds of laser beams (red, green, and blue) illuminate these 3N holograms under the same condition. All the reconstructed images from these 3N holograms are projected and synthesized on the unilaterally direction-selective screen. The direction-selective axis of the screen is set parallel to the direction of the film. Consequently the color components of the reconstructed images are diffusely reflected and the angular components are reflected back in the original direction. The human eye can recognize a 3-D color image in the viewing zone enlarged through the vertical diffusing effect of the screen.     

基于多视角采样校正的大尺度多投影光场显示系统

提出了一种基于多视角采样校正的大尺度多投影光场三维显示系统,系统采用了360台投影仪环绕投影在直径3 m、高1.8 m的柱形各向异性散射屏上,并在柱形屏内部精确重构出物体的三维光场。该系统能在360范围内显示可供多人多角度同时观看的具有平滑运动视差的大尺度三维场景,其中动态场景的绘制帧率达30 frame/s及以上,具有流畅的动态效果。设计了一种宽场柱面屏幕投影镜头来扩展投影仪画幅,并设计了一种基于相机多角度采样的光场自动校正方法,用于校正宽场镜头引入的非线性畸变以及系统装配引入的误差,实现了对360台投影仪光场的拼接融合。     

Multimedia ambiance communication

The photo-realistic 3-D image space of multimedia ambiance communication offers enhanced interpersonal communication. Formed by taking the laws of perspective and the characteristics of human visual perception into account, the space provides a natural environment that users can feel to be a part of. It is based on the concept of a three-layer structure, with long-, mid-, and short-range views. We constructed a testbed for multimedia ambiance communication consisting of a high-speed graphics computer and a curved screen onto which images are stereoscopically projected from the rear, and developed a three-camera system for capturing environment images. In addition, we developed the two-plane expression for processing backdrop views and highly efficient mid-range views. Finally, we constructed a photo-realistic 3-D image space using these image processing techniques     

Flat Projection for 3-D

The two challenges for three-dimensional (3-D) display are designing the optics for wide fields of view, and delivering pixels at the rates needed to support this. Getting such pixel rates at low cost is merely an extension of the key challenge for two-dimensional (2-D) displays,and the cost advantage of projection in this respect over alternatives increases considerably at the data rates needed for 3-D. Both 2-D and 3-D projection concepts are bulky, so the authors describe how to project images within a flat panel. Flat projection is not only inexpensive: it can generate virtual as well as real images, and allows the screen to take images and input from the viewer as well as vice versa. Real images are created by pointing a projector into a wedge-shaped light guide, and either the projector or the screen can be shuttered in order to time-multiplex a 3-D image on a large screen. Virtual images are created by pointing a projector into a slab embossed with a grating and can deliver the collimated illumination needed if a liquid crystal display is to time-multiplex a 3-D image with the high off-screen resolution provided by holograms.     

A 36 fps SXGA 3-D Display Processor Embedding a Programmable 3-D Graphics Rendering Engine

In this paper, a 3D display processor embedding a programmable 3D graphics rendering engine is proposed. The proposed processor combines a 3D graphics rendering engine and a 3D image synthesis engine to support both true realism and interactivity for the future multimedia applications. Using high coherence between 3D graphics data and 3D display inputs, both pipelines are merged by sharing buffers such that a 3D display engine directly uses the output of a 3D graphics rendering engine. The merged architecture has synergetic coupling effects such as freely providing various rendering effects to 3D images and easily computing disparities without complex extraction processes. In the 3D image synthesis engine, we adopt view interpolation algorithm and propose real-time synthesis method, pixel-by-pixel process. The view interpolation algorithm reduces the number of images to be rendered, resulting in the reduction of external memory size to 64.8% compared to conventional synthesis process. The proposed pixel-by-pixel process synthesizes 3D images at 36 fps through bandwidth reduction of 26.7% and decreases internal memory size to 64.2% compared to typical image-by-image process. The 3D graphics rendering engine is programmable and supports the instruction sets of the latest 3D graphics standard APIs, Pixel Shader 3.0 and OpenGL|ES 2.0. The die contains about 1.7 M transistors, occupies 5 mm times 5 mm in 0.18 mum CMOS and dissipates 379 mW at 1.85 V.