Real-time tracking of people has many applications in computervision and typically requires multiple cameras;for instance for surveillance, domotics, elderly-care and video conferencing. However, this problem is very...
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ISBN:
(纸本)9780819489487
Real-time tracking of people has many applications in computervision and typically requires multiple cameras;for instance for surveillance, domotics, elderly-care and video conferencing. However, this problem is very challenging because of the need to deal with frequent occlusions and environmental changes. Another challenge is to develop solutions which scale well with the size of the camera network. Such solutions need to carefully restrict overall communication in the network and often involve distributed processing. In this paper we present a distributed person tracker, addressing the aforementioned issues. Real-time processing is achieved by distributing tasks between the cameras and a fusion node. The latter fuses only high level data based on low-bandwidth input streams from the cameras. This is achieved by performing tracking first on the image plane of each camera followed by sending only metadata to a local fusion node. We designed the proposed system with respect to a low communication load and towards robustness of the system. We evaluate the performance of the tracker in meeting scenarios where persons are often occluded by other persons and/or furniture. We present experimental results which show that our tracking approach is accurate even in cases of severe occlusions in some of the views.
In order to achieve highly accurate motion control and path planning for a mobile robot, an obstacle avoidance algorithm that provided a desired instantaneous turning radius and velocity was generated. This type of ob...
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ISBN:
(纸本)9780819489487
In order to achieve highly accurate motion control and path planning for a mobile robot, an obstacle avoidance algorithm that provided a desired instantaneous turning radius and velocity was generated. This type of obstacle avoidance algorithm, which has been implemented in California State University Northridge's intelligent Ground Vehicle (IGV), is known as Radial Polar Histogram (RPH). The RPH algorithm utilizes raw data in the form of a polar histogram that is read from a Laser Range Finder (LRF) and a camera. A desired open block is determined from the raw data utilizing a navigational heading and an elliptical approximation. The left and right most radii are determined from the calculated edges of the open block and provide the range of possible radial paths the IGV can travel through. In addition, the calculated obstacle edge positions allow the IGV to recognize complex obstacle arrangements and to slow down accordingly. A radial path optimization function calculates the best radial path between the left and right most radii and is sent to motion control for speed determination. Overall, the RPH algorithm allows the IGV to autonomously travel at average speeds of 3mph while avoiding all obstacles, with a processing time of approximately 10ms.
A mobile robot equipped with a stereo camera can measure both the video image of a scene and the visual disparity in the scene. The disparity image can be used to generate a collection of points, each representing the...
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ISBN:
(纸本)9780819489487
A mobile robot equipped with a stereo camera can measure both the video image of a scene and the visual disparity in the scene. The disparity image can be used to generate a collection of points, each representing the location of a surface in the visual scene as a 3D point with respect to the location of the stereo camera: a point cloud. If the stereo camera is moving, e. g., mounted on a moving robot, aligning these scans becomes a difficult, and computationally expensive problem. Many finely tuned versions of the iterative closest point algorithm (ICP) have been used throughout robotics for registration of these sets of scans. However, ICP relies on theoretical convergence to the nearest local minimum of the dynamical system: there is no guarantee that ICP will accurately align the scans. In order to address two problems with ICP, convergence time and accuracy of convergence, we have developed an improvement by using salient keypoints from successive video images to calculate an affine transformation estimate of the camera location. This transformation, when applied to the target point cloud, provides ICP an initial guess to reduce the computational time required for point cloud registration and improve the quality of registration. We report ICP convergence times with and without image information for a set of stereo data point clouds to demonstrate the effectiveness of the approach.
This paper describes the main activities and achievements of our research group on Machine Intelligence and Robotics (Grima) at the computer Science Department, Pontificia Universidad Catolica de Chile (PUC). Since 20...
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This paper describes the main activities and achievements of our research group on Machine Intelligence and Robotics (Grima) at the computer Science Department, Pontificia Universidad Catolica de Chile (PUC). Since 2002, we have been developing an active research in the area of indoor autonomous social robots. Our main focus has been the cognitive side of Robotics, where we have developed algorithms for autonomous navigation using wheeled robots, scene recognition using vision and 3D range sensors, and social behaviors using Markov Decision Processes, among others. As a distinguishing feature, in our research we have followed a probabilistic approach, deeply rooted in machine learning and Bayesian statistical techniques. Among our main achievements are an increasing list of publications in main Robotics conference and journals, and the consolidation of a research group with more than 25 people among full-time professors, visiting researchers, and graduate students.
In order to maximize the use of a robotic probe during its limited lifetime, scientists immediately have to be provided the best achievable visual quality of 3D data products. The EU FP7-SPACE Project PRoVisG (2008-20...
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ISBN:
(纸本)9780819489487
In order to maximize the use of a robotic probe during its limited lifetime, scientists immediately have to be provided the best achievable visual quality of 3D data products. The EU FP7-SPACE Project PRoVisG (2008-2012) develops technology for the rapid processing and effective representation of visual data by improving ground processing facilities. In September 2011 PRoVisG held a Field Trials campaign in the Caldera of Tenerife to verify the implemented 3D vision processing mechanisms and to collect various sets of reference data in representative environment. The campaign was strongly supported by the Astrium UK Rover Bridget as a representative platform which allows simultaneous on-board mounting and powering of various vision sensors such as the Aberystwyth ExoMars PanCam Emulator (AUPE). The paper covers the preparation work for such a campaign and highlights the experiments that include standard operations-and science-related components but also data capture to verify specific processing functions. We give an overview of the captured data and the compiled and envisaged processing results, as well as a summary of the test sites, logistics and test assets utilized during the campaign.
In this paper we propose a novel approach for low cost multimodal detection of humans with mobile service robots. Detecting people is a key capability for robots that operate in populated environments. The main object...
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In this work, we address a situation presented as a new requirement for the Autonomous Challenge portion of the 2011 intelligent Ground Vehicle Competition (IGVC). This new requirement is to navigate between red and g...
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ISBN:
(纸本)9780819489487
In this work, we address a situation presented as a new requirement for the Autonomous Challenge portion of the 2011 intelligent Ground Vehicle Competition (IGVC). This new requirement is to navigate between red and green colored flags placed within the normal white painted lane lines. The regular visionalgorithms had to be enhanced to reliably identify and localize the colored flags, while the Navigation algorithms had to be modified to satisfy the constraints placed on the robot while transiting through the flag region. The challenge in finding a solution was the size of the flags, the possibility of loosing them against the background, as well as their movement in the wind. The attendant possibility of false positives and negatives also needed to be addressed to increase reliability of detection. Preliminary tests on the robot have produced positive results.
Mobile systems exploring Planetary surfaces in future will require more autonomy than today. The EU FP7-SPACE Project ProViScout (2010-2012) establishes the building blocks of such autonomous exploration systems in te...
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ISBN:
(纸本)9780819489487
Mobile systems exploring Planetary surfaces in future will require more autonomy than today. The EU FP7-SPACE Project ProViScout (2010-2012) establishes the building blocks of such autonomous exploration systems in terms of robotics vision by a decision-based combination of navigation and scientific target selection, and integrates them into a framework ready for and exposed to field demonstration. The PRoViScout on-board system consists of mission management components such as an Executive, a Mars Mission On-Board Planner and Scheduler, a Science Assessment Module, and Navigation & vision Processing modules. The platform hardware consists of the rover with the sensors and pointing devices. We report on the major building blocks and their functions & interfaces, emphasizing on the computervision parts such as image acquisition (using a novel zoomed 3D-Time-of-Flight & RGB camera), mapping from 3D-TOF data, panoramic image & stereo reconstruction, hazard and slope maps, visual odometry and the recognition of potential scientifically interesting targets.
In geometric calibration of stereoscopic cameras the object is to determine a set of parameters which describe the mapping from 3D reference coordinates to 2D image coordinates, and indicate the geometric relationship...
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ISBN:
(纸本)9780819489487
In geometric calibration of stereoscopic cameras the object is to determine a set of parameters which describe the mapping from 3D reference coordinates to 2D image coordinates, and indicate the geometric relationships between the cameras. While various methods for stereo cameras with ordinary lenses can be found from the literature, stereoscopic vision with extremely wide angle lenses has been much less discussed. Spherical stereoscopic vision is more and more convenient in computervision applications. However, its use for 3D measurement purposes is limited by the lack of an accurate, general, and easy-to-use calibration procedure. Hence, we present a geometric model for spherical stereoscopic vision equipped by extremely wide angle lenses. Then, a corresponding generic mathematical model is built. Method for calibration the parameters of the mathematical model is proposed. This paper shows practical results from the calibration of two high quality panomorph lenses mounted on cameras with 2048x1536 resolutions. Here, the stereoscopic vision system is flexible, the position and orientation of the cameras can be adjusted randomly. The calibration results include interior orientation, exterior orientation and the geometric relationships between the two cameras. The achieved level of calibration accuracy is very satisfying.
The proceedings contain 32 papers. The topics discussed include: engineering robust intelligentrobots;different micromanipulation applications based on common modular control architecture;recognizing and tracking hum...
ISBN:
(纸本)9780819479327
The proceedings contain 32 papers. The topics discussed include: engineering robust intelligentrobots;different micromanipulation applications based on common modular control architecture;recognizing and tracking humans and vehicles using radar;object tracking by co-trained classifiers and particle filters;teaching and implementing autonomous robotic lab walkthroughs in a biotech laboratory through model-based visual tracking;LandingNav: a precision autonomous landing sensor for robotic platforms on planetary bodies;real-time 3D environment model for obstacle detection and collision avoidance with a mobile service robot;handling of split-and-merge effects and occlusions using feature-based probabilistic data association;robust obstacles detection and tracking using disparity for car driving assistance;and modeling of radial asymmetry in lens distortion facilitated by modern optimization techniques.
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