一种头发动态模拟方法

该文提出了一种新奇的方法来表示头发,该方法建立在离散层次细节模型上,通过恰当重组和细分来表示头发。这种离散层次细节模型包括：单根头发,头发簇和头发束,通过一个基轴来控制头发的运动。基轴用四叉树数据结构来重组和细分。在运行时,通过头发的运动、头发是否可见以及与视点的距离来选择恰当的离散和连续头发层次表示。头发的碰撞检测算法是通过扫描体来快速准确交叉计算。同时,这些头发模拟和碰撞检测的方法在头发运动的整体性能和可视质量上达到一种柔性平衡。此外,该方法能够模拟不同的发型、各种头发的长度以及头发的运动。     

一种三维头发的仿真方法

头发的仿真一直是计算机图形学中最具挑战性的问题之一.为了得到真实感的头发图像,运用了基于NURBS曲面的头发建模方法,由悬臂梁模型在头部曲面附近生成关键头发曲线;调节控制点改变曲线形状;构造NURBS曲面四边形带代替头发簇;在头部模型对头发进行光照渲染,可以使用纹理方法映射颜色纹理和alpha纹理以生成真实头发.最后碰撞检测与响应手段增强了头发动态感.仿真结果表明,上述方法可以获得具有比较逼真效果的头发图像.     

基于头发的人头检测与跟踪

人头检测与跟踪技术是目前一个极具挑战性的研究课题,目前的一些研究中．比较少的学者研究头发捡测这一领域。研究的内容是基于单摄像头的人头栓测与跟踪。主要特色是利用头发检测对摄像头中读出来的图像数据进行初步处理、分析,并最终实现对人头的检测与跟踪。最后将检测到的人头标识出来。     

多雷达多目标跟踪仿真系统

该文提出了模块化、易扩展的多雷达多目标跟踪仿真系统软硬件结构,分析了仿真系统各模块的原理、功能,介绍了系统实现的关键技术。系统的研制成功地解决了雷达数据仿真、大批次和复杂机动目标跟踪、数据融合技术,并为各种算法的性能评估提供了研究平台。     

Wetting Effects in Hair Simulation

There is considerable recent progress in hair simulations, driven by the high demands in computer animated movies. However, capturing the complex interactions between hair and water is still relatively in its infancy. Such interactions are best modeled as those between water and an anisotropic permeable medium as water can flow into and out of the hair volume biased in hair fiber direction. Modeling the interaction is further challenged when the hair is allowed to move. In this paper, we introduce a simulation model that reproduces interactions between water and hair as a dynamic anisotropic permeable material. We utilize an Eulerian approach for capturing the microscopic porosity of hair and handle the wetting effects using a Cartesian bounding grid. A Lagrangian approach is used to simulate every single hair strand including interactions with each other, yielding fine‐detailed dynamic hair simulation. Our model and simulation generate many interesting effects of interactions between fine‐detailed dynamic hair and water, i.e., water absorption and diffusion, cohesion of wet hair strands, water flow within the hair volume, water dripping from the wet hair strands and morphological shape transformations of wet hair.     

A Stable Analytical Solution Method for Car-Like Robot Trajectory Tracking and Optimization

In this paper, the car-like robot kinematic model trajectory tracking and control problem is revisited by exploring an optimal analytical solution which guarantees the global exponential stability of the tracking error. The problem is formulated in the form of tracking error optimization in which the quadratic errors of the position, velocity, and acceleration are minimized subject to the rear-wheel car-like robot kinematic model. The input-output linearization technique is employed to transform the nonlinear problem into a linear formulation. By using the variational approach, the analytical solution is obtained, which is guaranteed to be globally exponentially stable and is also appropriate for real-time applications. The simulation results demonstrate the validity of the proposed mechanism in generating an optimal trajectory and control inputs by evaluating the proposed method in an eight-shape tracking scenario.     

基于3D人脸跟踪的实时真人虚拟试发

真人虚拟试发在虚拟社交、在线商城试戴和个人发型设计等领域具有明显的应用价值.现有的基于图像的2D虚拟试发系统无法让用户从不同的角度和距离实时观看试发效果,极大地限制了这类系统的可应用范围.为此,提出一个基于3D人脸跟踪的实时真人虚拟试发系统,用户仅使用一个网络摄像头,就能如同在镜子前试戴真实假发一样进行虚拟试发.首先结...     

Hair Modeling and Simulation by Style

As the deformation behaviors of hair strands vary greatly depending on the hairstyle, the computational cost and accuracy of hair movement simulations can be significantly improved by applying simulation methods specific to a certain style. This paper makes two contributions with regard to the simulation of various hair styles. First, we propose a novel method to reconstruct simulatable hair strands from hair meshes created by artists. Manually created hair meshes consist of numerous mesh patches, and the strand reconstruction process is challenged by the absence of connectivity information among the patches for the same strand and the omission of hidden parts of strands due to the manual creation process. To this end, we develop a two‐stage spectral clustering method for estimating the degree of connectivity among patches and a strand‐growing method that preserves hairstyles. Next, we develop a hairstyle classification method for style‐specific simulations. In particular, we propose a set of features for efficient classifications and show that classifiers trained with the proposed features have higher accuracy than those trained with naive features. Our method applies efficient simulation methods according to the hairstyle without specific user input, and thus is favorable for real‐time simulation.     

一个基于TOSSIM的异构传感器网络仿真方案

TOSSIM提供了每一节点运行相同应用的传感器网络仿真实验方法,但很多传感器网络中各节点需要运行的应用各不相同.为了用TOSSIM仿真这类异构传感器网络,从结构上分析了TOSSIM不能仿真异构传感器网络的原因,通过拓展Main配件的StdControl接口,引入事件响应控制机制,从而解决了在TOSSIM的单线程仿真模式下不能直接仿真异构传感器网络的问题,并成功实现了多个异构传感器网络的TOSSIM仿真实验.仿真结果分析表明在TOSSIM中实现规模可扩展的异构传感器网络仿真实验是可能的.     

基于OpenGL的卫星跟踪仿真

基于开放式三维图形程序标准OpenGL的卫星三维仿真实现,论述了在VC 6.0中利用OpenGL进行三维仿真的优点,以及卫星几何模型的构建、卫星运动轨迹的确定、仿真过程的动态显示以及系统软件的主要功能和实现。由此得到了效果比较好的卫星跟踪仿真图。因受限于目前的计算机技术尚不能做到对卫星上所有设备进行图形显示监测,但是卫星三维视觉仿真对于卫星检测系统和卫星管理系统依然具有很大的实用价值。     

基于VRML的机动目标CCD跟踪的视景仿真

实现机动目标CCD跟踪的视景仿真对装备训练和基于图像的跟踪算法设计具有重要意义。该文介绍在Matlab软件平台下利用基于VRML的虚拟现实工具箱进行视景仿真的基本步骤,以机动目标CCD跟踪的视景仿真为目的,针对虚拟场景的构建、3D目标机动和虚拟CCD跟踪等问题,提出相应的解决方法,并给出仿真结果。     

基于OpenGL的卫星跟踪仿真

基于开放式三维图形程序标准OpenGL的卫星三维仿真实现，论述了在VC＋＋6．0中利用OpenGL进行三维仿真的优点，以及卫星几何模型的构建、卫星运动轨迹的确定、仿真过程的动态显示以及系统软件的主要功能和实现。由此得到了效果比较好的卫星跟踪仿真图。因受限于目前的计算机技术尚不能做到对卫星上所有设备进行图形显示监测．但是卫星三维视觉仿真对于卫星检测系统和卫星管理系统依然具有很大的实用价值。     

四旋翼无人机可视化轨迹跟踪仿真系统

为了便于对四旋翼无人机控制算法进行实验仿真和验证,联合Solidworks和Matlab/SimMechanics工具箱设计了一种四旋翼无人机可视化轨迹跟踪仿真系统;利用Solidworks搭建了四旋翼无人机三维实体模型,并通过Solidworks和Matlab转换接口将该实体模型导入到Matlab/SimMechanics中;Matlab/SimMechanics提供了了三维可视化窗口,可以显示无人机的实时仿真状态;仿真平台在Matlab/SimMechanics环境中实现,与Matlab/Simulink通信方便,可方便的将Simulink设计好的控制算法添加到仿真系统中,以进行验证和参数整定,还具有姿态分析和数据分析等功能;轨迹跟踪仿真结果表明,四旋翼无人机可视化轨迹跟踪仿真系统直观可视,准确可靠,能较好地对控制算法进行研究和测试,对四旋翼无人机以及控制算法的研究和开发具有重要价值。     

Simulation Guided Hair Dynamics Modeling from Video

In this paper we present a hybrid approach to reconstruct hair dynamics from multi‐view video sequences, captured under uncontrolled lighting conditions. The key of this method is a refinement approach that combines image‐based reconstruction techniques with physically based hair simulation. Given an initially reconstructed sequence of hair fiber models, we develop a hair dynamics refinement system using particle‐based simulation and incompressible fluid simulation. The system allows us to improve reconstructed hair fiber motions and complete missing fibers caused by occlusion or tracking failure. The refined space‐time hair dynamics are consistent with video inputs and can be also used to generate novel hair animations of different hair styles. We validate this method through various real hair examples.     

Fast Hair and Head Tracking System Using 3D Image Sensor

In this paper, we propose a system that can detect and track hair regions of heads automatically and runs at video-rate （30 frames per-second） by making use of both the color and the depth information obtained from a Kinect. Our system has three characteristics： （1） Using a 6D feature vector to describe both the 3D color feature and 3D geometric feature ofa pixel uniformly; （2） Classifying pixels into foreground （e.g., hair） and background with K-means clustering algorithm; （3） Selecting and updating the cluster centers of foreground and background before and during hair tracking automatically. Our system can track hair of any color or any style robustly in clustered background where some objects have color similar to the hair or in environment where the illumination changes. Moreover, it can also be used to track faces （or heads） if the face （= skin ＋ hair） is selected as foreground.     

卫星可视化仿真与跟踪概论

系统仿真是第二次世界大战后发展起来的一门新技术．目前已广泛应用于工程与非工程的不同领域．它与航天技术的关系尤为密切。卫星仿真跟踪系统是天体力学、计算机图形学和数据库技术、软件工程等的交叉综合应用：包括地球模型构造．地球数据库和卫星数据库的建立：系统需要卫星地面接收站的硬件支持．同时加密解密算法的研究对于卫星数据的获取是不可或缺的条件。     

数字直扩接收机中同步环路设计与仿真

同步是扩频通信系统中的一个重要问题。该文详细介绍了直接序列扩频（DSSS）通信系统中，数字科斯塔斯（Costas）环、数字延迟锁定环（DLL）的工作原理和环路中二阶环路滤波器的设计方法，并根据该原理提出了一种新的码环实现方案。使用Matlab对数字直扩接收机进行了仿真。不同环路滤波器参数下环路捕获性能的仿真结果及系统解调误码率证明了该环路滤波器在Costas环和DLL环中的正确性和实用性。其较好地解决了直扩系统中载波和伪码精确同步的问题。该文所设计的数字直扩接收机可有效地应用于CDMA及GPS等系统之中。     

电视跟踪系统视景仿真方法研究

该文提出了一种面向通用雷达装备虚拟维修训练系统(VMTS)的电视跟踪系统视景仿真方法，建立了满足实时性与真实感的三维视景模型，并将几种跟踪算法相结合，实现了对目标的识别与跟踪，同时采用组件技术，满足了系统通用性的要求。     

飞行目标跟踪训练视景仿真技术研究

研究飞行器跟踪目标可视化问题,采用光电经纬仪作为操作训练系统.为了提高光电经纬仪操作手的训练水平,研究了经纬仪目标跟踪可视化视景仿真系统,克服了传统训练方法的诸多庇病,结合先进的OLED光学引擎,采用图像生成技术,提出了经纬仪所跟踪目标的三维飞行场景,实时显示了目标的飞行轨迹和各阶段的飞行姿态,能较好地满足操作手进行目标跟踪训练的需求.实际训练结果表明系统可以复现真实背景环境下操纵经纬仪进行瞄准、跟踪的过程,达到实战训练的目的,可为设计提供科学依据.     

一种应用于分布式目标跟踪仿真系统的算法调用方法

应用HLA技术构建了分布式雷达目标跟踪仿真环境;为使得目标跟踪算法应用独立于仿真系统,按照仿真组件技术的思想,通过分析仿真系统的静态功能模型和动态应用过程,绘出了目标跟踪算法调用方法的设计与应用;在分布式目标跟踪仿真系统中,算法调用方法实现了系统程序结构与具体算法应用的分离,并可以动态适应用户的算法应用需求;实践结果表明,算法调用方法可满足复杂多变的算法仿真应用,且保证了仿真系统的稳定性.