结构光视觉测量机器人的标定

构建了由线结构光测头和机器人组成的视觉测量系统. 利用齐次坐标变换的方法建立了测量系统的数学模型. 针对数学模型中的手眼关系, 使用半径已知的球体, 采用定点变位姿的方法, 进行粗略的估计. 考虑到机器人的绝对精度较低, 将定点信息和尺度信息作为优化条件, 对计算机器人的运动学参数和手眼关系做进一步寻优. 实验表明文中的方法能够有效提高测量机器人的重复精度.     

基于手眼立体视觉的机器人定位系统

研发了基于手眼的机器人定位系统,采用了眼在手上的单目摄像机,通过机械手的一次移动实现了立体视觉的功能.提出了一种方便有效手眼标定方法,避免了复杂的传统手眼标定过程,无需求解摄像机外参数和手眼变换矩阵.仅获取标定时刻的摄像机综合参数和机器人位姿,就可以在机器人基坐标系中视场范围内的任意两点进行检测,根据立体视觉的约束关系求解出目标物体在机器人基坐标中的位置,进而实现对目标物体的精确定位.     

三维视觉测量系统标定技术

在机器人视觉测量系统中,手眼标定问题一直是一个很重要也很难解决的问题.结合一个具体的实际系统,提出了一种将摄像机外参数矩阵和手眼矩阵合在一起标定的新方法,免去了传统的摄像机外参数标定和手眼标定的麻烦,并因此减小了误差,提高了测量精度.     

精确标定关节臂视觉检测系统手眼关系

在关节臂视觉检测系统中,视觉传感器与关节臂末端的手眼关系标定的准确性直接影响到系统的测量精度。推导了关节臂手眼问题的数学关系模型,提出了一种基于遗传优化算法的双阶段手眼标定的新方法,即先采用常规方法求取手眼变换矩阵主要参数的初始值,在初始值的基础上利用遗传算法优化手眼标定模型的所有参数,建立遗传优化算法的手眼关系数学模型。通过实验论证了该方法的优良性和可行性,对一般手眼问题具有一定的可移植性,系统测量精度优于40 μm。     

计算机视觉在机器人目标定位中的应用

计算机视觉是一门新兴的发展迅速的学科,计算机视觉的研究已经历了从实验室走向实际应用的发展阶段.由于视觉信息容量大,在实际应用中直观有效,所以运用视觉来寻找和确定目标的方位是机器人发展中一个很重要的方法,近年来它广泛应用于工业自动化装配领域中,同时对视觉系统的要求也越来越高.文中介绍并分析了当前国内外基于视觉的几种主要的目标定位方法在实际中的应用,例如移动机器人自主导航定位系统、手眼立体视觉系统等.     

一种用于三维物体定位的视觉方法

本文讨论了一种利用视觉信息对限定性物体在三维空间定位的方法。这项工作是一个在脱机的高级机器人语言控制下验证视觉系统的一部分。本文对这一视觉系统的整体结构及其与高级机器人语言系统的关系做了概要的介绍,并且着重讨论了其中的低级视觉信息处理模块的工作原理,以及利用视觉信息对三维空间中的物体进行定位的精度     

基于HALCON的机器人手眼标定精度分析与反演方法

通过视觉引导机器人完成抓取任务,机器人手眼标定的精度直接影响了抓取任务作业精度和抓取成功率。对于基于位置的机器人视觉引导系统,手眼标定的任务则是确定机器人坐标系与相机坐标系之间的位姿关系。通过HALCON平台,使用线性标定法实现了6DOF机器人的手眼标定。对手眼标定的结果进行反演,直观地展示了手眼标定的精确程度。最后通过采集多组不同数量的图片,在HALCON平台下验证了不同摄像机模型对手眼标定的精度影响,以及同种摄像机模型在不同数量图片的情况下手眼标定的标定精度。实验证明,根据位姿矩阵中待求解的未知量个数采集合适数量的图片和使用更精确的摄像机模型能够提高手眼标定的精度。     

新的单目视觉系统两步手眼标定方法

为了实现单目视觉系统的快速、精确的手眼标定,本文提出了一种新的两步式手眼标定方法,将手眼标定分为求解旋转关系和平移关系两步.首先机器人携带标定板进行两次平移运动求解旋转关系,然后机器人工具坐标系执行若干次旋转运动求解平移关系.该方法简单快速,不需要昂贵的外部设备,通过实验最终验证了该方法的可行性.     

眼在手上机器人手眼无标定三维视觉跟踪

在未标定手眼关系及摄像机模型的情况下,建立了机器人三维视觉跟踪问题非线性视觉映射关系模型,并据此设计了基于人工神经网络的视觉跟踪控制器.仿真结果表明该算法能完全消除稳态跟踪误差,具有很强的环境适应性和容错能力,算法简单,易于实时实现.     

基于主动视觉的手眼矩阵和光平面标定方法

为解决现有基于主动视觉方法标定手眼矩阵和结构光平面操作较复杂的问题,提出一种基于主动视觉的同时标定手眼矩阵和光平面的方法。通过精确控制机器人做两次相互正交的平移运动,求解手眼矩阵的旋转部分;而后通过两次及以上带旋转运动,求解手眼矩阵的平移部分和光平面方程。该方法简单,无需使用特定靶标,标定过程只需3个特征点,即可实现机器人手眼矩阵和光平面方程的标定;实验结果证明了该方法的有效性。     

应用多个正交视角轮流逼近3维目标的坐标

为实现目标的快速、精确3维定位和跟踪,提出一种正交摄像机视频定位系统及其坐标轮流逼近的迭代定位算法。系统中平面摄像机光轴按照正交方式布置,拍摄方向均指向原点。不同于现有的大部分计算机视觉方法,本算法中没有影响定位效率和精度问题的图像配准操作。证明了迭代算法的收敛性。数值验证和实际试验表明,本算法计算简单、误差稳定性好,收敛快,因此具有良好的应用潜力。     

Visual station keeping for floating robots in unstructured environments

This paper describes the use of vision for navigation of mobile robots floating in 3D space. The problem addressed is that of automatic station keeping relative to some naturally textured environmental region. Due to the motion disturbances in the environment (currents), these tasks are important to keep the vehicle stabilized relative to an external reference frame. Assuming short range regions in the environment, vision can be used for local navigation, so that no global positioning methods are required. A planar environmental region is selected as a visual landmark and tracked throughout a monocular video sequence. For a camera moving in 3D space, the observed deformations of the tracked image region are according to planar projective transformations and reveal information about the robot relative position and orientation w.r.t. the landmark. This information is then used in a visual feedback loop so as to realize station keeping. Both the tracking system and the control design are discussed. Two robotic platforms are used for experimental validation, namely an indoor aerial blimp and a remote operated underwater vehicle. Results obtained from these experiments are described.     

基于双目视觉的运动目标跟踪与测量

在研究融合运动目标位置预测的Mean Shift跟踪算法和双目立体视觉中的空间点定位算法的基础上,基于双目视觉设计了双目立体视觉运动目标跟踪和测量系统,并在所进行的跟踪与测量实验中,提取了运动目标质心的三维坐标序列,实现了对目标深度和速度的测量。     

Automatic initialization for 3D soccer player tracking

As a special application of computer vision, automatic sports video analysis has been studied by some researchers. This sports video analysis via computer vision is a moderately challenging problem: it is more difficult than analyzing a video of a few laboratory members acting as in a simple scenario and is easier than analyzing a video of crowded people at a subway station. So the success of an analysis heavily depends on how much one can exploit the prior information on the sport and setting. The most challenging and important part would be the tracking of players (and ball). With a multi-camera system, 3D tracking is feasible which is much more meaningful than 2D tracking for the analysis. As an initial step of 3D player tracking from multi-view soccer videos, this paper deals with automatic initialization of player positions. Initial 3D positions can be estimated by exploiting some conditions of a soccer match. To make it robust, prior knowledge on the features of players is learnt by support vector machines (SVM). Experimental results show that the proposed system is efficient for general soccer sequences.     

基于室内外定位的校园LBS研究

提出基于室内外定位的校园LBS平台总体框架,设计中心平台、移动终端和信息亭结构。给出室内定位系统,研究基于ZigBee的室内无线定位网络的部署原则和方法,建立基于室内外定位的校园LBS平台原型演示验证系统,该系统实现了终端定位、地图查询、三维浏览、导航与导游、跟踪监控、短信通知等功能。     

The comparison of accommodative response and ocular movements in viewing 3D and 2D displays

Some people often appear asthenopia symptoms of eye fatigue, double vision, nausea, and dizziness while viewing 3D movies. By testing the changes of accommodation function and ocular movements during watching 3D and 2D movies, the factors in visual discomfort are confirmed in this study.20 subjects with normal visual acuity and binocular vision function view 3D and 2D movies with the same content for 30 min, and the amplitude of accommodation, binocular vergence ability, stereo-acuity, and tear break-up time of the subjects before and after viewing the films are measured. Furthermore, an open-field auto-refractor is utilized for synchronously testing the change of accommodative response while viewing 3D and 2D films, and Skalar IRIS tracking system is applied to record ocular movements through infrared positioning.In comparison with viewing 2D movies, the accommodative response and ocular movements reveal obvious changes while viewing 3D movies. The accommodation ability and binocular vergence ability obviously drop after viewing 3D movies; moreover, the stability of stereo-acuity and tear film also gets worse. The changes of such physiological factors might be the major cause of asthenopia.     

基于多视角视频的运动重建

为了更逼真地从视频图像序列中实现三维人体骨架动画形式的提取,以便进一步地对人体运动进行分析与研究,提出了一种基于多视角视频的运动重建的方法。该方法充分利用了标记点的信息,其核心步骤有标定摄像机,提取标记点,跟踪标记点和人体运动三维重建四个主要方面。其中,在跟踪标记点时,使用了基于多视觉的目标跟踪算法,该算法由结合了扩展卡尔曼滤波预测与标记点轨迹平滑性约束所构成的双目立体视觉跟踪与多目视觉数据融合两个方面。实验结果证明了所提方法的有效性与可行性。     

多目相机的三维人体运动分析

本文提出了一个从三维voxel数据当中获取和跟踪人体骨架的算法。我们通过16台照相机得到人体的voxel数据,它是三维空间中定义一个点的图象信息的单位,包含每个点的X、Y和Z三个坐标等信息。从多目摄像机获得的三维人体voxel数据当中提取准确的,实时的人体骨架信息是当前计算机视觉领域的一个研究热点和难题。借鉴量子遗传算法的思想,把其中的迭代和优化思想运用到骨架的优化和提取是一种行之有效的办法。实验结果表明了该算法有较强的鲁棒性和有效性。     

Conics-enhanced vision approach for easy and low-cost 3D tracking

This paper presents a conics-enhanced vision approach for low-cost and easy-to-operate 3D tracking. The idea is to use paper disks as markers and recover the 3D positions of these paper disks by a property of conics: the 3D rotation and translation information of a planar circle with known radius could be recovered from its elliptic projection in one image (Int. J. Comput. Vision 10(1) (1993) 7). This property implies that tracking a paper disk in 3D could be done by tracking its elliptic projection in a sequence of 2D images. Since ellipse tracking has to consider many factors such as occlusion, background, light and so on, it is difficult to develop a general algorithm that works for all situations. In this paper, we discuss algorithms for two types of ellipse tracking: real-time tracking of single, non-occluded ellipse and off-line tracking of multiple ellipses. They are used to develop a real-time tracker to control the camera movement in a virtual environment and a multiple-tracker system that works off-line to acquire human motion data to animate a 3D human model. Implementation details and experimental results of the tracking systems are presented. The proposed 3D tracking approach is valuable for applications where accuracy and speed are not very critical but affordability and operational ease are most concerned, e.g., the educational-purpose virtual environments for kids.     

基于双目立体视觉避障的四旋翼飞行器设计

将双目立体视觉技术融入四旋翼飞行器设计,通过两个在相对水平位置上的单目相机模拟人的眼睛,在双目立体视觉测距系统上经过图像采集、双目矫正、双目立体匹配等步骤得到视差结果,计算出深度信息并进行三维重构,实现四旋翼飞行器一键起飞、定高、定点巡航、悬停及自主避障。实验结果表明,所设计的飞行器响应速度快,跟随性能好,定位精度较高。