Three-dimensional polarimetric integral imaging

A three-dimensional (3D) polarimetric image sensing and display technique based on integral imaging is proposed. Three-dimensional polarization distribution of reflected light from a 3D object can be measured as elemental image arrays by a rotating linear polarizer. After the measurement of the polarization of the 3D object, the 3D polarimetric object can be reconstructed optically by displaying the polarization-selected elemental images in spatial light modulators with two quarter-wave plates. Experimental demonstration of 3D polarimetric imaging of a 3D object attached to two orthogonal linear polarizers is presented. To the best of our knowledge, this is the first report on 3D polarimetric sensing imaging and 3D optical reconstruction by integral imaging.     

集成成像大纵深物体的三维形貌获取技术

为了满足现代工业所需的大纵深物体的三维形貌获取需求,解决传统结构光三维形貌获取技术纵深较小的问题, 借助集成成像这种阵列式多视点获取技术,构建了基于集成成像的大纵深物体的三维形貌获取技术。从集成成像原理出发,分析了集成成像三维物点和同名像点之间的关系,得到集成成像光学获取系统参数和三维物体纵深极限之间的关系。在此基础上,利用相机和电动平移台构建了扫描式相机集成成像三维形貌获取系统,并对纵深从600 mm到3 600 mm相对独立的2个物体构建的大纵深三维物体进行了形貌获取。光学实验结果显示,该集成成像大纵深物体三维形貌获取技术能够单次获取纵深为3 600 mm的三维物体的三维形貌,为大纵深物体的三维形貌获取提供了技术支持。     

360°连续扫描的便携式三维激光雷达设计与开发

针对三维激光雷达在国内有巨大的应用市场,而国外商业三维激光雷达十分昂贵的现状,开发了一种360°连续扫描的便携式三维激光雷达系统。采用一个二维激光扫描仪与高精度转台连接,通过步进电机控制形成三维激光扫描。在分析系统误差来源的基础上,提出了系统误差校正方法,给出了三维坐标精确计算公式。实验结果表明,系统测量精度高,数据质量好。系统作用距离80 m,测距精度可达6 mm,测量速度每秒7256点,可满足室内室外大规模场景三维数据快速获取的需求,而成本仅是国外同类商业三维激光雷达价格的四分之一左右,且重量轻体积小,携带方便。     

Cu(111)三维表面岛对表面原子扩散影响的分子动力学研究

采用嵌入原子方法的原子间相互作用势，利用分子动力学方法计算了同质外延生长中不同层数的三维Cu(111)表面岛上表面原子扩散激活能，分析了三维表面岛的层数对表面原子交换扩散和跳跃扩散势垒的影响. 研究结果表明，二维Enrilich-Schwoebel(ES)势垒小于三维ES势垒，且三维ES势垒不随表面岛层数的增加而显著变化. 对于侧向表面为(100)的表面岛，表面原子沿〈011〉方向上的扩散行为，随表面岛层数增加而逐渐变化；在表面岛层数达到3层时，扩散路径上的势垒变化趋于稳定，表面原子扩散以下坡扩散为主. 对于侧面取向为(111)的表面岛，当表面岛层数大于3层后，开始呈现上坡扩散的可能. 关键词： 表面原子 扩散 分子动力学模拟     

动态全息三维显示研究最新进展

全息三维显示是真三维显示技术, 其原理是利用光学干涉记录和衍射再现将物体或场景的三维信息全部重建出来, 所以观看全息三维图像与观看真实物体或场景的效果一样. 近期全息研究领域有一些突破性的成果被报道, 将推动全息显示的应用不断走向成熟. 本文将重点介绍基于光学材料和空间光调制器为全息图承载载体的动态全息三维显示最新发展状况. 虽然动态全息三维显示研究仍然存在挑战, 但最近研究中已经利用光学材料实现了实时动态全息三维视频显示, 这为未来实现大尺寸、高分辨率、彩色全息真三维视频显示提供了可能.     

Investigation of resolution of the stereoscopic 3D images

Evaluation of 3D images is an important part of 3D display developments. In this paper, we propose an evaluation method which can reflect the characteristics of the stereoscopic 3D images in the depth direction. Perception of the depth planes is verified using a subjective evaluation method. Resolution of the stereoscopic 3D images which represents the distribution of the 3D images in the depth direction quantitatively is calculated and analyzed.     

平面三维显示技术的研究现状

平面三维显示技术是近年来最新出现的虚拟现实显示技术,其最大的特点是观察者无需使用任何辅助附加设备,直接用肉眼就可看到屏幕上显示的三维图像。为推进三维显示技术的发展,进一步研究了视差立体成像原理,并据此介绍几种平面三维显示方法及其工作原理,包括障栅立体显示、微柱透镜阵列立体显示、偏振片立体显示和基于微柱透镜立体显示原理的多视点系统,阐述并分析了系统的优缺点。以日本三洋公司的四视角立体显示装置、南京大学的多视点三维显示系统和NEC液晶科技的HDDP三维显示系统为例,描述了国内外该项技术近期的研究现状,分析了存在的技术难点,展望了该应用领域的发展前景。     

Computer-generated kinoforms of real-existing full-color 3D objects using pure-phase look-up-table method

A computational method based on pure-phase look-up-table (LUT) is proposed for generating kinoforms of full-color real-existing three-dimensional (3D) objects. The principle of the pure-phase LUT method is described. 3D depth as well as color information of a full-color 3D object is obtained by the full-color 3D profile measurement approach based on binocular vision. The obtained full-color 3D data is decomposed into red (R), green (G), and blue (B) channels, and kinoforms of each channel are calculated from the depth map and color information of the corresponding channel using the pure-phase LUT method. In order to reduce the speckle noise of reconstructed full-color 3D image, sequential kinoforms of each color channel are generated by adding dynamic-pseudorandom phase factor into the object domain. Numerical reconstruction and optical reconstruction with a phase-only spatial light modulator (SLM) show that, with the proposed method, full-color holographic 3D display of real-existing full-color 3D objects is available.     

Universal Fermi gases in mixed dimensions

We investigate a two-species Fermi gas in which one species is confined in a two-dimensional plane (2D) or one-dimensional line (1D) while the other is free in the three-dimensional space (3D). We discuss the realization of such a system with the interspecies interaction tuned to resonance. When the mass ratio is in the range 0.0351相似文献   

3D color reconstruction based on underwater RGB laser line scanning system

Laser line scanning (LLS) as an optical 3D survey method is recently used for underwater 3D imaging. This paper presents an approach for both 3D reconstruction and color restoration based on the LLS system. The system is set up with RGB laser scanning components for acquiring 3D data and color data at the same time. Direct calibration algorithms and RGB additive color model are involved for processing 3D color data. The experiment result shows that underwater targets can be feasibly 3D reconstructed with color texture simultaneously, at millimeter scales.     

3D multi-directional sensor with pyramid mirror and structured light

Structured-light-based 3D multi-directional sensors are widely used due to their flexible field of view (FOV), which is a significant benefit. Nevertheless, existing 3D multi-directional sensors based on linear lasers are only capable of measuring a slice of a 3D scene at low resolution. In addition, other 3D multi-directional sensors are capable of measuring 3D scenes by shooting 2D structured light patterns in different directions through curved mirrors. However, the projected and captured structured light patterns are blurred due to the optical aberration property of curved mirrors, resulting in inaccurate 3D reconstruction. This paper proposes a 3D, high-resolution, high-accuracy, real-time multi-directional sensor that utilizes pyramid mirrors to decompose the FOVs into different directions and reduce the optical aberration phenomenon. The mathematical model of the 3D sensor is presented, and the FOV is analyzed. A dual-frequency phase-shifting fringe pattern is used for 3D reconstruction in real time. Moreover, the sensor is calibrated using a planar circle calibration gauge and the Householder reflection constraint. Finally, the experimental results demonstrate that the measurement error of the 3D multi-directional sensor is less than 1 mm and 0.03 rad, thus verifying the method's feasibility.     

基于压缩感知的三维物体成像的简单计算方法

从压缩感知的原理入手,阐述了基于压缩感知的三维物体成像方法。为解决压缩感知三维物体成像计算量大的问题,重点提出了一种三维信息计算的简单方法。此方法通过两次压缩感知计算就可得到位于多个距离处的物体的三维信息,大大减少了计算量。对此方法进行了数值模拟,并分析了采样率的提高对于距离计算精度的影响;建立实际的三维成像系统,实验结果证明了这种方法的可行性。     

刚体与SPH耦合的三维数值方法研究

 研究了刚性体与SPH（Smoothed Particle Hydrodynamics）方法相耦合的计算方法和技术,以此技术为核心,在原有三维综合拉氏程序CL3D的基础上,研制了适用于斜侵彻问题数值研究的刚性弹体与SPH靶体耦合计算的拉氏三维数值模拟程序CRSPH3D。针对金属材料编入了Johnson-Cook本构模型计算模块,针对混凝土材料编入了Johnson-Holmquist本构模型及与之配套的损伤模型和状态方程等的计算模块。用研制的计算程序对弹体分别正碰和斜碰穿透中厚铝靶和侵彻厚混凝土靶的过程进行了数值模拟计算和分析。结果表明,对于铝靶穿透问题,模拟计算得到的弹体剩余速度、弹体动能损失和贯穿图像与实验结果符合得较好。对于混凝土靶的侵彻问题也得到了与实验现象一致的、定性合理的图像。     

全息干涉光学格点一到三维空间维度的简捷变换

采用计算机模拟技术,研究了激光全息干涉光学格点从一维、二维到三维的简易空间变换.采用镜像添加光束技术,改变光束配置,可以较容易地实现干涉场光学格点从二维到三维的空间变换.进一步研究发现,若改变入射光束的偏振方向,干涉场可由三维结构变为一维层状结构,并且层状结构周期最小可达半个光波长.本文对全息光刻制作各种空间维度,尤其是光学波段禁带的光子晶体提供了简捷可行的实验技术思路.     

Application d'un modéle de l'état liquide à une monocouche de xénon ou de krypton adsorbées sur la surface (0001) du graphite

A phenomenological model of three-dimensional (3D) liquids is applied to a xenon or krypton monolayer adsorbed on (0001) graphite. The rare-gas atoms are assumed to be mobile with a short-range order as in 3D liquids. From the study of the equilibrium 3D gas ? 2D solid and 3D gas ? 2D liquid, one can find with reasonable agreement the pressures and temperatures of the 2D triple point determined experimentally by other authors.     

Holographic correspondence in topological superconductors

We analytically derive a compatible family of effective field theories that uniquely describe topological superconductors in 3D, their 2D boundary and their 1D defect lines. We start by deriving the topological field theory of a 3D topological superconductor in class DIII, which is consistent with its symmetries. Then we identify the effective theory of a 2D topological superconductor in class D living on the gapped boundary of the 3D system. By employing the holographic correspondence we derive the effective chiral conformal field theory that describes the gapless modes living on the defect lines or effective boundary of the class D topological superconductor. We demonstrate that the chiral central charge is given in terms of the 3D winding number of the bulk which by its turn is equal to the Chern number of its gapped boundary.     

Combined lenticular lens for autostereoscopic three dimensional display

When an autostereoscopic three dimensional (3D) display based on a single lenticular lens keeps working for a long period, the thermal expansion of lenticular lens results in serious crosstalk and 3D image deterioration. To overcome this problem, a combined lenticular lens is proposed. The combined lenticular lens is composed of a single lenticular lens used in the traditional autostereoscopic 3D display, a transparent glue layer and a glass substrate. The design method of the combined lenticular lens and analysis of thermal expansion effect is given. A 42-inch autostereoscopic 3D display based on the combined lenticular lens is developed. The experiment results verify that the proposed combined lenticular lens effectively avoids the crosstalk and 3D image deterioration happened in the traditional autostereoscopic 3D display.     

Precise perimeter measurement for 3D object with a light-pen vision measurement system

A novel measurement scheme for a three-dimensional (3D) object's surface boundary perimeter is proposed. This scheme consists of three steps. First, a light-pen single-camera 3D coordinate vision measurement system is devised to obtain the 3D coordinates of a detected object's 3D surface boundary. Second, a novel 3D B-spline active contour is applied to converge to the object's 3D surface boundary accurately. Finally, for the convergent active contour, its true contour length is computed as the detected object's true perimeter. An experiment on a bent surface's perimeter measurement indicates that this scheme's measurement repetition error decreases to 0.6%.     

一种考虑硅通孔电阻-电容效应的三维互连线模型

硅通孔(TSV)是三维集成电路的一种主流技术.基于TSV寄生参数提取模型,对不同物理尺寸的TSV电阻-电容(RC)参数进行提取,采用Q3D仿真结果验证了模型精度.分析TSVRC效应对片上系统的性能及功耗影响,推导了插入缓冲器的三维互连线延时与功耗的解析模型.在45nm互补金属氧化物半导体工艺下,对不同规模的互连电路进行了比较分析.模拟结果显示,TSVRC效应导致互连延时平均增加10%,互连功耗密度平均提高21%;电路规模越小,TSV影响愈加显著.在三维片上系统前端设计中,包含TSV寄生参数的互连模型将有助于设计者更加精确地预测片上互连性能.     

光谱法计算机三维成象与再现系统

本文提出一种全新的计算机立体视觉新方法—光谱法三维成象与再现.文中分析了该方法的基本原理和系统结构,并推导出了获取三维面形信息的三角算法计算公式,最后给出了实验结果.结论表明,该方法作为一种全新的立体视觉方法,具有原理简洁、计算快、精度高的特点,能够对物体进行快速成象并再现物体的三维形状,且结构简单,有很强的实用性.