一种基于向量运算的三维真实感纹理映射方法

为增强三维场景中纹理映射的真实感及映射效率,提出一种快捷且便于实现的基于向量运算的纹理映射方法。该方法实现方便,具有较高的处理速度。     

基于立体分光原理的三维立体显示技术

关键技术：本项目提供了一种易于实现,价格低廉,观看舒适,立体呈现性能出色的三维立体显示系统。该系统采用立体分光原理,以两台上下普通液晶显示器分别提供左眼和右眼影像,使用时观众只需佩戴偏光眼镜进行观看,就能欣赏到高质量的三维立体显示效果。为了便于该项技术的产业化,我们同时提出了与硬件显示系统配套的软件媒体解决方案,使得该项目可以在二维和三维显示之间自由切换,使该项目更具有市场投资潜力。     

基于立体分光原理的三维立体显示技术

本项目提供了一种易于实现,价格低廉,观看舒适,立体呈现性能出色的三维立体显示系统。该系统采用立体分光原理,以两台上下普通液晶显示器作为人机交互平台,使用时观众只需佩戴偏光眼镜进行观看,就能欣赏到高质量的三维立体显示效果。该系统同时可以在二维和三维显示之间自由切换。     

三维建模中的纹理处理

纹理是影响三维模型逼真程度的最主要因素，当三维模型建立以后，需要将纹理映射在DSM上，真实地模拟三维景观。在大范围的城市三维建模中，纹理处理的工作量非常大，因此如何进行纹理处理是城市三维建模中的关键。本文将对城市三维建模中采用航空遥感影像和地面摄影影像进行地表纹理、建筑物顶部以及侧面纹理等处理的有关问题进行讨论。     

大面积三维地形生成和显示技术及实现

大面积三维地形的生成与显示是军事仿真视景系统开发的难点问题.本文研究了解决此问题的关键技术,包括LOD、纹理映射、分页调度策略和大地形数据库管理;提出了应用上述技术的方案,利用Creator的地形建模模块,生成大面积地形,采用视景仿真软件Vega绘制虚拟场景,实验表明达到了良好的效果.     

三维曲线的计算机双色立体显示技术

文章系统地介绍了在计算机上采用双色法对三维曲线进行立体显示的原理和方法,并编制了相应程序。方法简单易行,能达到更好的视觉效果。     

三维立体显示综述

按基本工作原理是否为双目视差将三维立体显示分为两大类。基于双目视差原理的三维立体显示主要有眼镜/头盔式立体显示和光栅式自由立体显示,这类三维立体显示的技术相对成熟并有相应产品;非基于双目视差原理的三维立体显示主要有全息立体显示、集成成像立体显示和体显示等,这类三维立体显示的技术较不成熟,大多没有相应产品。对这些三维立体显示的器件结构、工作原理以及各自的特性进行了阐述。     

三维表面纹理高度重建中的光线不均校正

因三维表面纹理能比二维纹理更好地表现物体的纹理信息,而且随场景光照及视角的变化而变化,所以被广泛用于虚拟现实以及计算机游戏等技术之中。Photometric Stereo作为一种有效的获取三维表面纹理信息的技术而被人们所广泛关注。均匀的光照条件是Photometric Stereo捕获和重建三维表面纹理成功的关键条件。在现实应用中,不均匀光照会导致三维表面纹理在捕获和重建过程中发生失真和畸变。针对这种失真和畸变进行了研究,并提出了一种解决此类问题的方法。实验结果表明,该方法简单可行,有效。     

纹理映射技术在三维游戏引擎中的应用

游戏引擎是游戏的心脏,它在后台控制着游戏中各个模块同时有序的工作,渲染模块是游戏引擎中最复杂,也是最能体现游戏效果的模块。纹理映射技术的应用能增强场景绘制的真实感并能提高场景的渲染速度。该文是对三维游戏引擎中的渲染模块的初步研究,首先介绍了三维游戏引擎系统以及纹理映射技术,使用OpenGL图形库实现了大环境天空盒、三维地形的贴图效果、并加入了地面建筑物,再现了真实的三维场景。介绍了纹理映射技术在三维游戏引擎中的应用及作用。     

真三维立体显示技术

当今 ,在二维平面显示器流行的时代 ,一种三维立体显示器及其相关技术正在迅速兴起 .通过介绍常用的几种表示三维数据的显示方式 ,解释了基于体素的三维显示技术 ,并介绍说明了三维显示技术的几种主要类型 ,然后在此基础上 ,又重点介绍了真三维立体显示技术的基本原理、主要技术的发展过程 ,并对采用该技术的几种主要产品的基本原理进行了必要的说明 ;接着解释了真三维立体显示器的一些主要性能参数 ,比较了几种目前最新产品的性能 ;最后 ,对真三维显示器的应用前景作了简要阐述 .     

一种基于面积比不变性约束的曲面纹理算法

文中运用两步映射原理解决了曲面的参数化问题,改进了一种采用面积比不变性约束的球冠映射算法,消除了采用传统的整球面和半球面参数化方法向中间曲面作映射所带来的纹理变形问题,进而较好地实现了由非参数化面片拼接成的曲面表面的纹理映射。     

纹理映射在模型优化中的应用

三维模型的构建是虚拟现实及视景仿真系统中最基本、最重要的组成部分之一。构建三维模型需考虑到场景浏览的真实感与实时性,因而需要建立一个最优化的可视化模型。本文比较了在虚拟现实系统中模型优化的方法,采用了纹理映射代替多边形建模创建高效真实感模型的优化手段,着重介绍了颜色纹理和凹凸纹理的相关理论和方法,并应用于视景仿真系统中,极大的提高了实时性,并保证了真实感。     

虚拟城市建设中纹理库及模型库建立研究

虚拟城市是对城市的三维逼真表达,它不仅具有多种细节层次的几何表达,还提供具有相片质感的表面描述.在虚拟城市建设中,纹理数据及三维模型数据对于虚拟城市建设速度,运行效率,逼真性、沉浸感都有着至关重要的作用.从系统和科学的角度出发,以快速高效构建虚拟城市模型为目的,基于530平方公里虚拟城市模型建设及虚拟小区精细模型建设实践基础,探讨了虚拟城市模型建设过程中纹理库及模型库的建设及应用,解决了传统纹理数据及模型数据的无序、低效利用问题.实践表明,纹理库及模型库对于逼真虚拟城市模型的快速高效构建发挥着至为重要的作用.     

人-车-路视景仿真系统中信息的动态显示

为了提高人-车-路系统视景仿真时的逼真度,在介绍利用Vega API和Symbology模块显示英文字符的基础上,论述了利用OpenGL在Vega视景仿真线程中动态显示中英文混合信息的技术原理,提出了使用回调函数和OpenGL无闪烁动态显示仿真状态信息的方法,并给出了基于Visual C++开发平台的伪代码实现。     

三维地形场景的真实感绘制

三维地形场景的真实感绘制追求的两个目标是绘制的逼真度和绘制的实时性,需要在不明显降低图像质量的条件下保持较高的交互帧速率。为了满足实时性的需求,采用连续LOD算法和其它技术来加速地形绘制：为了满足逼真度的需求,采用SAR图像进行纹理映射,采用光照映射实现场景照明和明暗处理。     

Effects of using head-up display in automobile context on attention demand and driving performance

This study aimed to investigate the difference in driving performance between drivers’ attention on the head-up display (HUD)/road under low/high road conditions via a driving simulator experiment. Experimental driving included four driving scenarios with attention-on-the-HUD followed by attention-on-the-road or vice versa under high or low driving load conditions. Each scenario took about a 30-min driving consisting of two 15-min sections for each attention location. Forty-eight participants, divided into four groups, drove one of the four scenarios once. Besides driving safely within speed limit, participants were also required to perform detection task and speed limit sign response task. Results revealed that drivers paying attention to the HUD, under both low and high driving load conditions, reacted faster to speed limit sign changes than when paying attention to the road. In addition, attention-to-the-HUD under low driving load condition caused the smallest variation in steering wheel angle and lateral acceleration. These differences can be attributed to the driver's enhanced awareness and the cognitive capture effect, and tended to diminish with increasing driving workload. Finally, attention shift of drivers and the so-called novelty effect for using new technology product were also found.     

Influence of wall charge distribution on time lag of address discharge in AC plasma display panels

The influence of wall charge distribution on the time lag of address discharge in an AC plasma display panel is investigated using two different reset waveforms: one (typical reset) induces both face and surface discharges and the other (TR reset) induces face discharges only. The measured formative time lag and statistical time lag of address discharge for TR were 21–31 ns and 31–74 ns shorter than the one for the typical reset, respectively. The TR reset resulted in much less increase of statistical time lag than the typical reset when the reset-to-address time interval was increased, and 70 ns smaller deviation of the statistical time lag among different color cells. Calculations show that the TR reset forms a much smoother wall charge profile, which is less susceptible to cell parameter variations, than the typical reset. The observed differences in the time lags of address discharge between different scan lines and color cells are strongly correlated to the differences of the wall charge profile, indicating that a smooth wall charge profile formed by the reset using face discharges only reduces the time lag of address discharge and minimizes the susceptibility of address discharge to cell parameter variation.     

Adaptive detection of range-spread targets in compound Gaussian clutter with the square root of inverse Gaussian texture

The compound Gaussian clutter with the square root of inverse Gaussian texture component has been successfully used for modeling the heavy-tailed non-Gaussian clutter measured by high-resolution radars. In high-resolution radars, the targets may extend along multiple consecutive range cells, which are called range-spread targets. In this paper, we consider the range-spread target detection problem in the compound Gaussian clutter with the square root of inverse Gaussian texture. Three adaptive detectors are proposed based on Bayesian one-step generalized likelihood ratio test, maximum a posteriori generalized likelihood ratio test and Bayesian two-step generalized likelihood ratio test, respectively. Finally, the detection performances of the proposed detectors are evaluated by the Monte Carlo simulation. The simulation results show that the proposed detectors have better detection performance of range-spread target than the conventional generalized likelihood ratio test detector.     

Visual ergonomics of video-display-terminal workstations: Field measurements of luminance for various display settings

Electronic visual displays have shown a rapid technological evolution in the last two decades. With reference to the ergonomic requirements for video display terminal (VDT) workstations (ISO 9241), at an international level, attention is focused on the human–system interaction. With reference to visual ergonomics, the aim of this study is to assess luminance conditions through in-field measurements in order to evaluate: luminance and contrast ratios, luminance and contrast non-uniformities. The assessment was applied to widespread flat screen displays and repeated for fourteen combinations of Contrast–Brightness. The analysis carried out by the Authors shows the importance of realizing a simple and quick procedure to determine the performance levels of displays used in VDT workstations. The proposed assessment could be used as a practical tool for staff assigned to assess the risks arising from VDT use in the workplace within the Occupational Health and Safety Assessment Procedure.     

三维视频中实现多个视频同时播放

研究了在三维视频中实现多个视频同时播放。为拓展多媒体技术的应用空间,使其与工程应用更接近,通过多媒体技术和OpenGL技术相结合,设计了一个立体视频播放器。它能在立体图形的不同面上播放不同的视频,而且可以在多个2D平面上同时播放多个不同的视频。2D图形和3D图形可以进行灵活自如的变形、移动、旋转等操作。实验结果表明,该播放器播放画面平滑自然,播放视频的数目可自由选择,多个视频间互不干扰,达到一种比较良好和理想的播放效果。