架空输电线路巡线机器人的视觉导航

巡线机器人沿相线行走时必须探测识别和定位各种障碍物,并根据障碍类型规划越障行为。针对220 kV架空输电线路的结构特点,利用视觉传感器,设计了基于结构约束的障碍识别算法,完成了障碍识别和分类。根据障碍物的结构特点,设计了一种自适应多窗口区域立体匹配算法,实现了障碍物的双目视觉定位。模拟线路实验结果表明,算法能可靠地从复杂背景中识别并定位出防振锤、悬垂线夹和耐张线夹等障碍物,满足了巡线机器人导航要求。     

基于人脸识别与光流追踪的移动机器人视觉导航方法

针对移动机器人视觉导航中跟踪目标丢失的问题,提出了基于人脸识别与稀疏光流算法(KLT)结合的移动机器人视觉导航方法(FR-KLT视觉导航方法)。采用OpenCV库中的Haar特征提取人脸识别算法实时检测识别目标人脸,通过Harris角点检测获取目标人体特征点,对目标人体进行精准定位;KLT光流追踪法测算目标移动趋势,并预测目标下一刻大致位置。目标人体位置变动时移动机器人对目标进行实时追踪导航。通过Pioneer-LX机器人在真实环境下试验,验证了该方法准确识别并跟踪目标的实时性和有效性。     

移动机器人寻迹算法研究

传统的寻迹算法控制下的移动机器人通过复杂路径时常产生路径识别错误。针对这种情况,首先将移动机器人的寻迹过程抽象成运动学模型,然后将模糊PID算法应用于机器人控制,并针对交叉路径的识别问题提出了改进的寻迹算法。实验证明：采用所述算法后,机器人能正确地识别交叉道,实现了对复杂路径的准确、快速跟踪。     

面向医院的移动机器人导航系统设计

本文设计了一种采用RFID和机器视觉相结合的自主移动机器人导航系统.该系统在搜索和识别走廊内RFID标签和门牌号的基础上实现自定位和导航.本文首先给出了移动机器人导航系统的整体设计,然后分别给出了基于RFID辅助定位方法和基于DSP的门牌号识别方法,最后在博创UpVoyager移动机器人平台上验证了本系统的有效性.     

Indoor scene recognition by a mobile robot through adaptive object detection

Mobile robotics has achieved notable progress, however, to increase the complexity of the tasks that mobile robots can perform in natural environments, we need to provide them with a greater semantic understanding of their surrounding. In particular, identifying indoor scenes, such as an Office or a Kitchen, is a highly valuable perceptual ability for an indoor mobile robot, and in this paper we propose a new technique to achieve this goal. As a distinguishing feature, we use common objects, such as Doors or furniture, as a key intermediate representation to recognize indoor scenes. We frame our method as a generative probabilistic hierarchical model, where we use object category classifiers to associate low-level visual features to objects, and contextual relations to associate objects to scenes. The inherent semantic interpretation of common objects allows us to use rich sources of online data to populate the probabilistic terms of our model. In contrast to alternative computer vision based methods, we boost performance by exploiting the embedded and dynamic nature of a mobile robot. In particular, we increase detection accuracy and efficiency by using a 3D range sensor that allows us to implement a focus of attention mechanism based on geometric and structural information. Furthermore, we use concepts from information theory to propose an adaptive scheme that limits computational load by selectively guiding the search for informative objects. The operation of this scheme is facilitated by the dynamic nature of a mobile robot that is constantly changing its field of view. We test our approach using real data captured by a mobile robot navigating in Office and home environments. Our results indicate that the proposed approach outperforms several state-of-the-art techniques for scene recognition.     

Reactive Visual Navigation Based on Omnidirectional Sensing – Path Following and Collision Avoidance

Described here is a visual navigation method for navigating a mobile robot along a man-made route such as a corridor or a street. We have proposed an image sensor, named HyperOmni Vision, with a hyperboloidal mirror for vision-based navigation of the mobile robot. This sensing system can acquire an omnidirectional view around the robot in real time. In the case of the man-made route, road boundaries between the ground plane and wall appear as a close-looped curve in the image. By making use of this optical characteristic, the robot can avoid obstacles and move along the corridor by tracking the close-looped curve with an active contour model. Experiments that have been done in a real environment are described.     

机器人双目视觉系统的算法研究与实现

针对计算机视觉系统在移动机器人中的应用,对摄像机标定、图像分割、模式识别、目标距离探测以及双目视觉系统在移动机器人导航中的运用进行分析与研究。文章提出了在特定三维场景中,对不同研究对象采取不同处理方式的复合算法,实现了对于机器人视野内简单几何物体的识别,同时使用双目摄像机结构,直接探测出目标物体相对于机器人的深度距离及其方位角度。     

基于局部显著区域的自然场景识别

场景识别是移动机器人实现拓扑导航的关键。针对未知环境,提出一种基于视觉局部显著区域的自然场景识别方法。首先,提出带反馈的显著性检测模型(FSDM)自底向上进行图像分析;然后,根据显著位置,基于分形实现自动尺度选择,以构造合适尺寸的局部显著区域。对场景图像中的显著区域采用梯度方向、二阶不变矩、归一化色调3种特征进行不变性表示,并根据其匹配率实现场景识别。实验结果表明,FSDM具有较高的显著性检测精度。而且室内室外环境的多次场景识别实验也表明,该方法与全局外观方法相比能够更好地容忍尺度、视角等变化引起的差异,静态场景识别具有较高的准确性。     

Autonomous exploration using rapid perception of low-resolution image information

We present a technique for mobile robot exploration in unknown indoor environments using only a single forward-facing camera. Rather than processing all the data, the method intermittently examines only small 32×24 downsampled grayscale images. We show that for the task of indoor exploration the visual information is highly redundant, allowing successful navigation even using only a small fraction of the available data. The method keeps the robot centered in the corridor by estimating two state parameters: the orientation within the corridor, and the distance to the end of the corridor. The orientation is determined by combining the results of five complementary measures, while the estimated distance to the end combines the results of three complementary measures. These measures, which are predominantly information-theoretic, are analyzed independently, and the combined system is tested in several unknown corridor buildings exhibiting a wide variety of appearances, showing the sufficiency of low-resolution visual information for mobile robot exploration. Because the algorithm discards such a large percentage of the pixels both spatially and temporally, processing occurs at an average of 1000 frames per second, thus freeing the processor for other concurrent tasks.     

Development of an indoor navigation system for a monocular-vision-based autonomous mobile robot

We have developed a technology for a robot that uses an indoor navigation system based on visual methods to provide the required autonomy. For robots to run autonomously, it is extremely important that they are able to recognize the surrounding environment and their current location. Because it was not necessary to use plural external world sensors, we built a navigation system in our test environment that reduced the burden of information processing mainly by using sight information from a monocular camera. In addition, we used only natural landmarks such as walls, because we assumed that the environment was a human one. In this article we discuss and explain two modules: a self-position recognition system and an obstacle recognition system. In both systems, the recognition is based on image processing of the sight information provided by the robot’s camera. In addition, in order to provide autonomy for the robot, we use an encoder and information from a two-dimensional space map given beforehand. Here, we explain the navigation system that integrates these two modules. We applied this system to a robot in an indoor environment and evaluated its performance, and in a discussion of our experimental results we consider the resulting problems.     

一种多目标快速识别的自适应灰度量化方法研究

针对实时序列图像多目标识别问题提出了一种快速图像处理方法。该方法依据一定的先验知识和准则，对复杂背景图像进行窗口化，对每一个窗口独立进行自适应快速中值滤波，及基于局部图像灰度信息的自适应重新量化和最大熵分割处理，实现了对全景视场内预定目标的快速准确提取和识别。为动态环境中多目标条件下移动机器人的视觉定位、导航和目标跟踪所需图像处理技术提供了一种新的方法。     

Reinforcement based mobile robot navigation in dynamic environment

In this paper, a new approach is developed for solving the problem of mobile robot path planning in an unknown dynamic environment based on Q-learning. Q-learning algorithms have been used widely for solving real world problems, especially in robotics since it has been proved to give reliable and efficient solutions due to its simple and well developed theory. However, most of the researchers who tried to use Q-learning for solving the mobile robot navigation problem dealt with static environments; they avoided using it for dynamic environments because it is a more complex problem that has infinite number of states. This great number of states makes the training for the intelligent agent very difficult. In this paper, the Q-learning algorithm was applied for solving the mobile robot navigation in dynamic environment problem by limiting the number of states based on a new definition for the states space. This has the effect of reducing the size of the Q-table and hence, increasing the speed of the navigation algorithm. The conducted experimental simulation scenarios indicate the strength of the new proposed approach for mobile robot navigation in dynamic environment. The results show that the new approach has a high Hit rate and that the robot succeeded to reach its target in a collision free path in most cases which is the most desirable feature in any navigation algorithm.     

Robust place recognition based on omnidirectional vision and real-time local visual features for mobile robots

Topological localization is especially suitable for human–robot interaction and robot’s high level planning, and it can be realized by visual place recognition. In this paper, bag-of-features, a popular and successful approach in pattern recognition community, is introduced to realize robot topological localization. By combining the real-time local visual features proposed by ourselves for omnidirectional vision and support vector machines, a robust and real-time visual place recognition algorithm based on omnidirectional vision is proposed. The panoramic images from the COLD database were used to perform experiments to determine the best algorithm parameters and the best training condition. The experimental results show that the robot can achieve robust topological localization with high successful rate in real time by using our algorithm.     

A realistic benchmark for visual indoor place recognition

An important competence for a mobile robot system is the ability to localize and perform context interpretation. This is required to perform basic navigation and to facilitate local specific services. Recent advances in vision have made this modality a viable alternative to the traditional range sensors, and visual place recognition algorithms emerged as a useful and widely applied tool for obtaining information about robot’s position. Several place recognition methods have been proposed using vision alone or combined with sonar and/or laser. This research calls for standard benchmark datasets for development, evaluation and comparison of solutions. To this end, this paper presents two carefully designed and annotated image databases augmented with an experimental procedure and extensive baseline evaluation. The databases were gathered in an uncontrolled indoor office environment using two mobile robots and a standard camera. The acquisition spanned across a time range of several months and different illumination and weather conditions. Thus, the databases are very well suited for evaluating the robustness of algorithms with respect to a broad range of variations, often occurring in real-world settings. We thoroughly assessed the databases with a purely appearance-based place recognition method based on support vector machines and two types of rich visual features (global and local).     

神经网络在机器人视觉图像命令识别中的应用

在智能机器人技术中,视觉识别是关键.在智能机器人视觉系统获得的图像中,由于图像倾斜而造成的识别错误是视觉识别难以解决的问题.针对机器人所要完成的具体任务,对机器人的视觉识别问题进行探讨,为实现机器人对图像命令的识别,首先对机器人视觉系统获得的倾斜图像,采用Hough变换进行倾斜度检测并进行校正,然后采用人工神经网络法进行识别,根据识别结果对机器人的下一步运动进行决策与控制,达到了预期的目的.实验结果表明,该方法具有较高的识别率.     

Identifying vegetation from laser data in structured outdoor environments

The ability to reliably detect vegetation is an important requirement for outdoor navigation with mobile robots as it enables the robot to navigate more efficiently and safely. In this paper, we present an approach to detect flat vegetation, such as grass, which cannot be identified using range measurements. This type of vegetation is typically found in structured outdoor environments such as parks or campus sites. Our approach classifies the terrain in the vicinity of the robot based on laser scans and makes use of the fact that plants exhibit specific reflection properties. It uses a support vector machine to learn a classifier for distinguishing vegetation from streets based on laser reflectivity, measured distance, and the incidence angle. In addition, it employs a vibration-based classifier to acquire training data in a self-supervised way and thus reduces manual work. Our approach has been evaluated extensively in real world experiments using several mobile robots. We furthermore evaluated it with different types of sensors and in the context of mapping, autonomous navigation, and exploration experiments. In addition, we compared it to an approach based on linear discriminant analysis. In our real world experiments, our approach yields a classification accuracy close to 100%.     

适用于机器人视觉的手势识别系统

手势是一种高效的人机交互和设备控制的方式,基于视觉的手势识别是人机交互、模式识别等领域的一个富有挑战性的研究课题。文章提出并实现了一个可用于与机器人交互的静态手势检测和识别系统。该系统用摇动检测的方法定位人手;用基于现场采样得到的肤色模型进行手的分割;用简化并改进的CAMSHIFT算法对手势进行跟踪;最后用模式识别的方法提取简单特征进行识别。实验证明,该系统快速、稳定而有效。     

Robot semantic mapping through human activity recognition: A wearable sensing and computing approach

Semantic information can help robots understand unknown environments better. In order to obtain semantic information efficiently and link it to a metric map, we present a new robot semantic mapping approach through human activity recognition in a human–robot coexisting environment. An intelligent mobile robot platform called ASCCbot creates a metric map while wearable motion sensors attached to the human body are used to recognize human activities. Combining pre-learned models of activity–furniture correlation and location–furniture correlation, the robot determines the probability distribution of the furniture types through a Bayesian framework and labels them on the metric map. Computer simulations and real experiments demonstrate that the proposed approach is able to create a semantic map of an indoor environment effectively.     

Mobile robot navigation and scene modeling using stereo fish-eye lens system

We present an autonomous mobile robot navigation system using stereo fish-eye lenses for navigation in an indoor structured environment and for generating a model of the imaged scene. The system estimates the three-dimensional (3D) position of significant features in the scene, and by estimating its relative position to the features, navigates through narrow passages and makes turns at corridor ends. Fish-eye lenses are used to provide a large field of view, which images objects close to the robot and helps in making smooth transitions in the direction of motion. Calibration is performed for the lens-camera setup and the distortion is corrected to obtain accurate quantitative measurements. A vision-based algorithm that uses the vanishing points of extracted segments from a scene in a few 3D orientations provides an accurate estimate of the robot orientation. This is used, in addition to 3D recovery via stereo correspondence, to maintain the robot motion in a purely translational path, as well as to remove the effects of any drifts from this path from each acquired image. Horizontal segments are used as a qualitative estimate of change in the motion direction and correspondence of vertical segment provides precise 3D information about objects close to the robot. Assuming detected linear edges in the scene as boundaries of planar surfaces, the 3D model of the scene is generated. The robot system is implemented and tested in a structured environment at our research center. Results from the robot navigation in real environments are presented and discussed. Received: 25 September 1996 / Accepted: 20 October 1996     

基于视觉的同时定位与地图构建方法综述

基于视觉的自主导航与路径规划是移动机器人研究的关键技术,对基于视觉的计算机导航与同时定位及地图构建（SLAM）方法近三十年的发展进行了总结和展望。将视觉导航分为室内导航和室外导航,并详细阐述了每一种子类型的特点和方法。对于室内视觉导航,列举了经典导航模型和技术方法,探讨了解决SLAM问题的最新进展：HTM-SLAM算法和基于特征的算法;对室外视觉导航,阐述了国际国内目前的研究动态。