基于几何－拓扑广域三维地图和全向视觉的移动机器人自定位

面向大规模室内环境, 研究了基于全向视觉的移动机器人自定位. 提出用分层的几何－拓扑三维地图管理广域环境特征, 定义了不同层次的三维局部环境特征及全局拓扑属性, 给出了分层地图的应用方法. 构建了全向视觉传感器成像模型及其不确定性传播方法, 使得地图中的概率元素能够在系统中有效应用. 采用随机点预估搜索的方法提取环境元素对应的曲线边缘特征. 用带反馈的分层估计方法在融合中心对多观测特征产生的相应估计状态进行总体融合. 以分层逻辑架构设计实现了移动机器人交互式自定位系统. 实验分析了真实环境中不同初始位姿和观测信息情况下定位系统的收敛性和定位精度, 在考虑动态障碍物的遮挡情况下完成了机器人的在线环境感知和运动自定位任务. 实验结果表明本文方法的可靠性和实用性.     

一种新颖实用的基于视觉导航的三维重建算法

根据立体视觉在视觉导航应用中的特点，提出了由视差图重建三维场景的整套算法。首先，推导视差图里各点在摄像机坐标系下的三维坐标。其次，建立摄像机坐标系与车体坐标系的转换关系，得到更有实际意义的在车体坐标系下各点的三维坐标。最后，通过分格显示地貌的算法，大大减少了数据量。实验结果表明，该算法计算量小、鲁棒性强，完全满足视觉导航中的实时性、准确性要求。     

嵌入式应用系统中3D鼠标的应用

介绍了3D鼠标的底层通信原理及在嵌入式应用系统中的使用价值,讨论了嵌入式应用系统中3D鼠标的软件设计方法并给出了应用程序。     

基于视觉的目标检测与跟踪综述

基于视觉的目标检测与跟踪是图像处理、计算机视觉、模式识别等众多学科的交叉研究课题,在视频监控、虚拟现实、人机交互、自主导航等领域,具有重要的理论研究意义和实际应用价值.本文对目标检测与跟踪的发展历史、研究现状以及典型方法给出了较为全面的梳理和总结.首先,根据所处理的数据对象的不同,将目标检测分为基于背景建模和基于前景建模的方法,并分别对背景建模与特征表达方法进行了归纳总结.其次,根据跟踪过程有无目标检测的参与,将跟踪方法分为生成式与判别式,对基于统计的表观建模方法进行了归纳总结.然后,对典型算法的优缺点进行了梳理与分析,并给出了其在标准数据集上的性能对比.最后,总结了该领域待解决的难点问题,对其未来的发展趋势进行了展望.     

3D Reconstruction by Shadow Carving: Theory and Practical Evaluation

Cast shadows are an informative cue to the shape of objects. They are particularly valuable for discovering object’s concavities which are not available from other cues such as occluding boundaries. We propose a new method for recovering shape from shadows which we call shadow carving. Given a conservative estimate of the volume occupied by an object, it is possible to identify and carve away regions of this volume that are inconsistent with the observed pattern of shadows. We prove a theorem that guarantees that when these regions are carved away from the shape, the shape still remains conservative. Shadow carving overcomes limitations of previous studies on shape from shadows because it is robust with respect to errors in shadows detection and it allows the reconstruction of objects in the round, rather than just bas-reliefs. We propose a reconstruction system to recover shape from silhouettes and shadow carving. The silhouettes are used to reconstruct the initial conservative estimate of the object’s shape and shadow carving is used to carve out the concavities. We have simulated our reconstruction system with a commercial rendering package to explore the design parameters and assess the accuracy of the reconstruction. We have also implemented our reconstruction scheme in a table-top system and present the results of scanning of several objects.     

Mushaca: A 3-Degrees-of-Freedom Mouse Supporting Rotation

Based on kinesiology research demonstrating that translation and rotation are inseparable actions in the physical world, we present Mushaca, a 3-degrees-of-freedom mouse that senses rotation in addition to traditional planar position. We present an optical realization of the Mushaca device based on two optical sensors and then evaluate the device through a series of controlled experiments. Our results show that rotation is indeed a useful input modality for a pointing device, and also give some insight into how users perceive the changing coordinate system of the rotating mouse and adapt to this change through kinesthetic learning.     

Koala 3D: A continuous climbing 3D printer

The size of manufactured parts is naturally bound by the size of their production machines. In this paper, we explore the alternative of making a machine that can continuously navigate along an object being fabricated, producing objects larger than itself. The machine combines a climbing robot and a 3D printer. It uses an infinite fabrication loop which includes printing, reanchoring to a new station, and printing again. We present the design, construction, and characterization of the machine along with experiments on the fabrication of vertical columns. We also demonstrate the freeform fabrication capabilities of the machine by printing a moai statue. The results obtained have a wide range of applications for construction, product fabrication and promisingly broaden the current applications of 3D printing.     

基于OpenGL的网格数据三维地形鼠标取值方法

在OpenGL的三维场景模拟中,通过鼠标取点得到该点的三维坐标一直是一个难题,而在三维地形模拟中则进一步要求通过鼠标取点得到该点在地形数据中的实际值,即用鼠标取值,因此OpenGL三维地形的鼠标取值一直是这类应用程序中的难点。文章在解决实际问题的基础上实现了一种解决基于OpenGL的网格数据的三维地形的鼠标取值方法。     

Vision-based 3-D trajectory tracking for unknown environments

This paper describes a vision-based system for 3-D localization of a mobile robot in a natural environment. The system includes a mountable head with three on-board charge-coupled device cameras that can be installed on the robot. The main emphasis of this paper is on the ability to estimate the motion of the robot independently from any prior scene knowledge, landmark, or extra sensory devices. Distinctive scene features are identified using a novel algorithm, and their 3-D locations are estimated with high accuracy by a stereo algorithm. Using new two-stage feature tracking and iterative motion estimation in a symbiotic manner, precise motion vectors are obtained. The 3-D positions of scene features and the robot are refined by a Kalman filtering approach with a complete error-propagation modeling scheme. Experimental results show that good tracking and localization can be achieved using the proposed vision system.     

三维物体表面轮廓测量中实用相位展开算法的研究

在利用FTP进行三维物体表面轮廓测量时,影响测量精度的关键因素之一是相位的展开算法。传统的相位展开算法受展开路径的影响。本文在传统相位展开算法的基础上,提出了一种实用的不完全依赖展开路径的相位展开算法,该算法使噪声对精度的影响可减到最小并且易于操作。     

TWIXT: A 3D animation system

This paper describes a visually interactive 3D computer animation system. Animation is controlled by lists of events stored in tracks. Tracks are interpolated by functions that have an arbitrary degree of knowledge about how to control display parameters. The system provides real time wireframe playback so the animator can see what the animation looks like and is both input and output device independent.     

Java3D扩展鼠标交互功能的研究与实现

介绍了Java3D本身提供的鼠标交互功能,针对三维仿真环境中暴露出的操作性、交互性不足的问题,提出了扩展鼠标点取功能的需求,即可以对场景中任意目标物体进行操作和控制.详细论述了Java3D扩展鼠标交互功能的实现方案:首先判断鼠标点击动作,然后在获取点击范围内所有目标的列表后选择目标对象进行操作.结合具体实现的代码阐述了扩展鼠标交互功能的一般性方法,继承、重载和改写了Java3D中相关的鼠标操作类,重点讲解了实现过程中技术难点的解决方案,最后阐明了此研究工作的价值.     

Java3D鼠标交互功能的扩展与应用

分析了Java3D提供的鼠标交互功能,针对场景比较复杂,待拾取物体相对距离近的虚拟环境中用户拾取不准的问题提出了一种解决思路：在鼠标移动过程中实时创建一条连接空间中的视点与投影平面上的鼠标点的射线,检测沿射线的方向是否有物体与之相交,若有则返回距离视点最近的与射线相交物体所在的节点,并在该节点上添加一个动画效果提示用户该节点是预选节点。重点讲解了具体的实现过程,在最后的部分结合实际应用背景验证了该方法可以有效地方便用户的拾取操作。     

Logitech三维鼠标及其在三维场景漫游中的应用

着重介绍了如何运用Ｌogitech３维鼠标作为３维场景漫游时的视点控制传感器,并提出了一种基于Ｗindows多线程的漫游框架。     

基于3DMAX的《三维建模制作》教学模式改革实践研究

3DMAX软件是Autodesk公司开发的三维动画渲染和制作软件,广泛用于建筑设计、三维动画、多媒体制作、游戏、辅助教学以及工程可视化等领域。聊城职业技术学院在对《三维建模制作》课程进行项目化课程开发和"做学教"一体化教学,模式改革、实践与研究过程中,围绕3DMAX软件功能在师生"做""学""教"三个能力层面和配套资源建设等方面的建设进行了探索和实践,提高了人才培养质量。     

Twins: A Dual Addressing Space Representation for Self-Organizing Networks

As the size of mobile self-organizing networks increases, the efficiency of location services must increase as well so that addressing/routing scalability does not become an issue. In this paper, we propose a novel architecture, called Twins, tailored for self-organizing networks. Twins architecture involves addressing and locating nodes in large networks, forwarding packets between them, and managing in the presence of mobility/topology changes. Twins defines a logical multidimensional space for addressing and forwarding, while location service and management operations make use of a one-dimensional space. To improve scalability and performance, forwarding is hop-by-hop with greedy next-hop choice and the location service uses a rendezvous paradigm to distribute information among nodes. In this paper, we describe the Twins architecture and present a performance evaluation to assess scalability, fairness in the overhead distribution among nodes, and routing robustness.     

Practical reliable Bayesian recognition of 2D and 3D objects usingimplicit polynomials and algebraic invariants

We treat the use of more complex higher degree polynomial curves and surfaces of degree higher than 2, which have many desirable properties for object recognition and position estimation, and attack the instability problem arising in their use with partial and noisy data. The scenario discussed in this paper is one where we have a set of objects that are modeled as implicit polynomial functions, or a set of representations of classes of objects with each object in a class modeled as an implicit polynomial function, stored in the database. Then, given partial data from one of the objects, we want to recognize the object (or the object class) or collect more data in order to get better parameter estimates for more reliable recognition. Two problems arising in this scenario are discussed: 1) the problem of recognizing these polynomials by comparing them in terms of their coefficients; and 2) the problem of where to collect data so as to improve the parameter estimates as quickly as possible. We use an asymptotic Bayesian approximation for solving the two problems. The intrinsic dimensionality of polynomials and the use of the Mahalanobis distance are discussed     

3D Semantic Scene Completion: A Survey

International Journal of Computer Vision - Semantic scene completion (SSC) aims to jointly estimate the complete geometry and semantics of a scene, assuming partial sparse input. In the last years...     

基于内容的三维模型检索综述

对当前基于内容的三维模型检索技术的国际研究现状及进展进行了广泛而深入的综述．探讨和分析了基于内容的三维模型检索技术的系统框架及其关键方法,重点介绍其中的模型坐标标准化、特征提取与索引、相似性匹配、查询方式与用户界面等方面的基本内容,并进行了适当分类．分析总结了现有的基于内容的三维模型检索系统及搜索引擎的典型实例．最后,对现有研究中存在的难点问题及其未来的发展方向进行了展望．     

mWorld: A multiuser 3D virtual environment

mWorld integrates 3D virtual-scene generation tools and synchronous, asynchronous, and time-dependent data communication techniques to enable cooperative 3D design and visualization across networks