基于osg粒子系统的海洋场景中下雪的仿真

针对虚拟现实领域中特殊天气、战斗等场景中需要雾、雨、云、火焰、爆炸等场景特效来提高场景逼真度,兼顾渲染实时性的问题,提出采用OSG的粒子系统进行仿真.在分析粒子系统实现原理的基础上,利用Open Scene Graph (OSG) 3.0.1开源场景图形开发库建立粒子特效系统模块,有效地解决特殊场景中对粒子效果的要求.利用基于FFT (Fast Fourier Transfer)算法的Gersmer模型的动态链接库进行大面积水域渲染仿真,并在此基础上添加雪效.     

基于多级粒子系统和新粒子形状的尾焰绘制*

针对目前大规模场景中导弹尾焰等特效绘制计算量大,导致系统实时性差等缺点,给出了一种基于多级粒子系统和新型粒子形状的尾焰绘制方法,在用三角函数勾画出轮廓后,对外部采用圆周发射新形状的粒子,内部采用特殊单面片作为基本粒子形状且用直线运动代替曲线运动,并采用了LOD结合GPU的粒子系统技术,在不影响真实感的情况下减少了计算量,有效提高了大规模场景中尾焰特效绘制的逼真度和实时性。     

基于GPU粒子系统的大规模场景高效雨雪实时模拟

粒子系统实现的雨雪效果能有效增强三维场景的真实感,传统基于中央处理器（CPU）运算模拟的粒子系统占用了大量CPU运算时间,难以达到实时模拟的要求。为此提出了一种基于图形处理器的（GPU）运算的粒子系统来模拟的雨雪场景。该方法通过在GPU中重复使用消亡粒子在视点坐标系内生成新粒子,并在几何着色器中将粒子的点坐标转换为矩形坐标,将CPU从复杂庞大的几何运算中解放出来,从而大幅增加了场景绘制的微粒数,使雨雪场景模拟的实时性和逼真度得到增强。     

基于粒子系统的污染气流扩散仿真

在虚拟场景中进行污染仿真实验时,需要对逼真度和实时性进行权衡。基于粒子系统给出一个模拟污染气流扩散的方法,用户通过调整粒子动力学方程中的参数可观察污染气流在不同环境下的运动变化。利用浓度场内空间粒子大小与透明度的逐渐变化,实现烟雾生成的逼真效果,达到降低粒子数量的目的。实验结果显示,该方法在普通PC平台上可以获得实时的绘制速度。     

基于OSG与Qt的FAST三维场景仿真

为解决FAST基地可视化的问题,开发了一套基于OpenSceneGraph(OSG)与Qt的三维场景仿真系统。通过三维建模,计算机程序自动化布局,OSG虚拟场景搭建等,将FAST的场景进行仿真显示。通过数据驱动实现对虚拟场景的实时更新,同时采用OSG的粒子系统来模拟雨雪天气特效场景。该系统将FAST的场景实时显现在技术工作人员面前,具有场景漫游,动态演示等基本人机交互功能,可为FAST基地的实践工作提供辅助决策依据。     

基于真实景物的虚拟现实场景的生成

在分析基于实景的虚拟现实场景建模特点的基础上,运用一个具体的实例来阐述了基于实景的虚拟现实场景的生成过程及其相关注意事项,通过合理建模减小复杂度、通过真实感贴图来增强逼真度、通过模型导入的对象化来实现对虚拟物体的控制、最终在逼真性、实时性和可控性方面都达到了较好的效果。     

基于汽车驾驶模拟器的实时雨雪效果模拟

针对传统粒子系统模拟动态景物不能兼顾系统的真实性与实时性,提出了一种实时雨雪特效模拟算法。该算法采用LOD技术,根据视点与粒子距离对雨雪进行分级,每级粒子进行不同的层次细节描述,同时引入着色器,充分利用GPU图形流水线的可编程性,将粒子系统的存储和运算交由GPU完成。将该算法应用到基于OSG图形开发包构建的汽车驾驶模拟系统中,仿真结果表明,该算法可以生成逼真的视觉效果,同时满足系统实时性的要求。     

虚拟现实场景的建模特点及生成效果

在分析了基于实景的虚拟现实场景建模特点的基础上,运用一个具体的实例来阐述了基于实景的虚拟现实场景的生成过程及其相关注意事项,通过合理建模减小复杂度、通过真实感贴图来增强逼真度、通过模型导入的对象化来实现对虚拟物体的控制。最终在逼真性,实时性和可控性方面都达到了较好的效果。     

虚拟飞行场景中事故特效的实时仿真

针对飞机的虚拟飞行仿真中,飞行事故仿真的真实感不强的问题,基于粒子系统, 结合动力学模型,实时渲染了爆炸、火焰、烟雾等飞行事故常见特效。使用四边形粒子代替传统 点粒子,结合纹理映射技术和融合技术,将真实感较强的纹理贴图与背景的帧缓存按照预设的融 合因子进行深度融合,提高了特效的真实感和实时性。通过粒子系统碰撞检测的方法,模拟烟雾 在飞机机舱内扩散,与舱壁发生碰撞的效果。搭建出模拟飞行的虚拟现实仿真系统,实现真实感 和沉浸感都很强的飞机爆炸、起火和冒烟等事故场景实时仿真。     

基于Vega Prime的灭火飞机投水特效模拟

为了模拟某型灭火飞机的投水特效,主要研究了基于粒子系统的投水特效.首先阐述了Vega Prime特殊效果模块中粒子系统的基本原理,然后采用面向视点的多边形来表示水粒子,通过具体设置粒子系统中粒子的颜色、透明度、大小、纹理、速度和位置等属性,逼真的模拟了飞机的投水特效.在模拟的过程中,将环境影响因素考虑进去,使用Vega Prime的API函数实现投水特效的实时性,同时将飞机坐标系中的速度转换到渲染的场景坐标系中,实现了投水特效随着飞机运动的效果.实践证明,使用粒子系统模拟飞机的投水特效,使三维真实感更强.     

VRML虚拟场景跳转实现

基于VRML(Virtual Reality Modeling Language)构造复杂三维场景时,通常需要多个场景的组合和链接。如何实现三维场景空间的流畅跳转则十分关键。本文结合实例介绍了利用Anchor组节点实现虚拟场景间跳转的方法,从而有效服务于网络中复杂三维虚拟场景空间的跳转。     

基于音乐视觉化的游戏设计与开发

为了解决游戏场景开发制作成本高、制作效率低的问题,结合实验游戏StarMusiX的创作,提出了一种设计游戏场景的新方法,即：实时分析在游戏运行过程中输入的外部数据,并将分析结果作为实时搭建游戏场景的驱动因素,进而实现场景及内容的过程化实时生成。实验游戏将“音乐”这一元素作为外部数据输入并分析,以“音乐视觉化”作为游戏场景形式表现,验证了上述思路的合理性和可行性。实验表明,此种方法有效地提高了游戏场景设计的效率。     

Movie scenes detection with MIGSOM based on shots semi-supervised clustering

The segmentation into scenes helps users to browse movie archives and to select the interesting ones. In a given movie, we have two kinds of scenes: action scenes and non-action scenes. To detect action scenes, we rely on tempo features as motion and audio energy. However, to detect non-action scenes, we have to use the content information. In this paper, we present a new approach to detect non-action movie scenes. The main idea is the use of a new dynamic variant of the self-organizing maps called MIGSOM (Multilevel Interior Growing self-organizing maps) to detect agglomerations of shots in movie scenes. The originality of MIGSOM model lies in its architecture for evolving the structure of the network. The MIGSOM algorithm is generated by a growth process by adding nodes where it is necessary, whether from the boundaries or the interior of the map. In addition, the advantage of the proposed MIGSOM algorithm is their ability to find the best structure of the output space through the training process and to represent better the semantics of the data. Our system is tested on a varied database and compared to the classical SOM and others works. The obtained results show the merit of our approach in term of recall and precision rates and that our assumptions are well founded.     

Self-distillation framework for indoor and outdoor monocular depth estimation

As one of the most crucial tasks of scene perception, Monocular Depth Estimation (MDE) has made considerable development in recent years. Current MDE researchers are interested in the precision and speed of the estimation, but pay less attention to the generalization ability across scenes. For instance, the MDE networks trained on outdoor scenes achieve impressive performance on outdoor scenes but poor performance on indoor scenes, and vice versa. To tackle this problem, we propose a self-distillation MDE framework to improve the generalization ability across different scenes in this paper. Specifically, we design a student encoder that extracts features from two datasets of indoor and outdoor scenes, respectively. After that, we introduce a dissimilarity loss to pull apart encoded features of different scenes in the feature space. Finally, a decoder is adopted to estimate the final depth from encoded features. By doing so, our self-distillation MDE framework can learn the depth estimation of two different datasets. To the best of our knowledge, we are the first one to tackle the generalization problem across datasets of different scenes in the MDE field. Experiments demonstrate that our method reduces the degradation problem when a MDE network is in the face of datasets with complex data distribution. Note that evaluating on two datasets by a single network is more challenging than evaluating on two datasets by two different networks.

     

基于VRML-Java的网络虚拟现实的实现

受到网络速度的限制,传统的网页只能显示文本和图片等二维信息,而网络虚拟现实技术把交互的、逼真的虚拟三维场景引入网络.虚拟现实建模语言（VRML）是一种在互联网上构筑三维虚拟场景的语言标准,通过VRML脚本节点及Java小应用程序实现了用户与虚拟场景更好的交互,并通过Java数据库连接（JDBC）,系统实现了三维场景与二维信息的集成.     

VRML描述的网上全景漫游

用Java语言描述、应用全景图像实现三维场景的虚拟漫游在因特网中巳得到了广泛应用，然而，用全景图像描述的场景，其景物和光照环境固定，场景交互性较差，场景切换不自然，在全景图像的基础上，提出应用虚拟实境建模语言（VRML）来描述虚拟场景的方法，不仅能够较简便地实现三维漫游，而且可改变相关景物和光照环境，场景的交互和切换更自然，适合于因特网中应用。     

Conspicuity in realistic scenes: an eye-movement measure

An experiment is described to measure the distracting effects of advertisements on the conspicuity of routing signs in realistic scenes. Slides of railway station scenes were shown in which subjects had to search for a target word used in a routing sign present in the scene. Eye movements were recorded to determine search time and number of fixations during search time. Both search time and number of fixations increased systematically with the number of advertisements in two of the three experimental scenes. The distribution of fixations over the scenes is discussed.     

图形场景交互操作的分析设计

本文主要介绍分析图形场景中的交互操作,并以表格形式和UML应用工具Rational Rose对图形场景中的基本操作进行了描述和分析,对一般的图形场景都适用。     

Study on Recognition Method of Similar Weather Scenes in Terminal Area

Weather is a key factor affecting the control of air traffic. Accurate recognition and classification of similar weather scenes in the terminal area is helpful for rapid decision-making in air traffic flow management. Current researches mostly use traditional machine learning methods to extract features of weather scenes, and clustering algorithms to divide similar scenes. Inspired by the excellent performance of deep learning in image recognition, this paper proposes a terminal area similar weather scene classification method based on improved deep convolution embedded clustering (IDCEC), which uses the combination of the encoding layer and the decoding layer to reduce the dimensionality of the weather image, retaining useful information to the greatest extent, and then uses the combination of the pre-trained encoding layer and the clustering layer to train the clustering model of the similar scenes in the terminal area. Finally, terminal area of Guangzhou Airport is selected as the research object, the method proposed in this article is used to classify historical weather data in similar scenes, and the performance is compared with other state-of-the-art methods. The experimental results show that the proposed IDCEC method can identify similar scenes more accurately based on the spatial distribution characteristics and severity of weather; at the same time, compared with the actual flight volume in the Guangzhou terminal area, IDCEC's recognition results of similar weather scenes are consistent with the recognition of experts in the field.     

图形场景交互操作的分析设计

本文主要介绍分析图形场景中的交互操作，并以表格形式和UML应用工具Rational Rose对图形场景中的基本操作进行了描述和分析，对一般的图形场景都适用。