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25
M2Tracker: A Multi-View Approach to Segmenting and Tracking People in a Cluttered Scene Using Region-Based Stereo
- International Journal of Computer Vision
, 2002
"... We present a system that is capable of segmenting, detecting and tracking multiple people in a cluttered scene using multiple synchronized cameras located far from each other. The system improves upon existing systems in many ways including: (1) We do not assume that a foreground connected compon ..."
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Cited by 225 (9 self)
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We present a system that is capable of segmenting, detecting and tracking multiple people in a cluttered scene using multiple synchronized cameras located far from each other. The system improves upon existing systems in many ways including: (1) We do not assume that a foreground connected component belongs to only one object; rather, we segment the views taking into account color models for the objects and the background. This helps us to not only separate foreground regions belonging to different objects, but to also obtain better background regions than traditional background subtraction methods (as it uses foreground color models in the algorithm). (2) It is fully automatic and does not require any manual input or initializations of any kind. (3) Instead of taking decisions about object detection and tracking from a single view or camera pair, we collect evidences from each pair and combine the evidence to obtain a decision in the end. This helps us to obtain much better detection and tracking as opposed to traditional systems.
Y.: Homography based multiple camera detection and tracking of people in a dense crowd
- In: Proc. of the IEEE CVPR
, 2008
"... Tracking people in a dense crowd is a challenging problem for a single camera tracker due to occlusions and extensive motion that make human segmentation difficult. In this paper we suggest a method for simultaneously tracking all the people in a densely crowded scene using a set of cameras with ove ..."
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Cited by 42 (2 self)
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Tracking people in a dense crowd is a challenging problem for a single camera tracker due to occlusions and extensive motion that make human segmentation difficult. In this paper we suggest a method for simultaneously tracking all the people in a densely crowded scene using a set of cameras with overlapping fields of view. To overcome occlusions, the cameras are placed at a high elevation and only people’s heads are tracked. Head detection is still difficult since each foreground region may consist of multiple subjects. By combining data from several views, height information is extracted and used for head segmentation. The head tops, which are regarded as 2D patches at various heights, are detected by applying intensity correlation to aligned frames from the different cameras. The detected head tops are then tracked using common assumptions on motion direction and velocity. The method was tested on sequences in indoor and outdoor environments under challenging illumination conditions. It was successful in tracking up to 21 people walking in a small area (2.5 people per m 2), in spite of severe and persistent occlusions. 1.
A peer-to-peer architecture for distributed real-time gesture recognition
- In International Conference on Multimedia and Exposition
, 2004
"... We describe a peer-to-peer multiple-camera architecture for distributed real-time gesture recognition system. Previ-ous work attaches multiple cameras to a server. This simpli-fies many design problems but is impractical for real-world installations. Our architecture uses a network of relatively ine ..."
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Cited by 12 (2 self)
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We describe a peer-to-peer multiple-camera architecture for distributed real-time gesture recognition system. Previ-ous work attaches multiple cameras to a server. This simpli-fies many design problems but is impractical for real-world installations. Our architecture uses a network of relatively inexpensive cameras to gather images in order to provide high resolution at low cost. Computations are done at the embedded processors in each camera, without using a cen-tralized server. We also propose a methodology for trans-forming well-defined single-camera algorithms to multiple cameras. We migrate our single-camera gesture recogni-tion system into multiple cameras with slightly overlapped views. In order to minimize the communication bandwidth and power consumption, only selected contours or ellipses information is transmitted between the cameras. 1.
Temporal Occupancy Grids: a Method for Classifying the Spatio-Temporal Properties of the Environment
- In Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS
, 2002
"... This paper introduces the concept of a temporal occupancy grid as a method for modeling and classifying spatial areas according to the time properties of their occupancy. The method extends the idea of occupancy grids[1] by considering occupancy over a number of different timescales. This paper pres ..."
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Cited by 11 (1 self)
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This paper introduces the concept of a temporal occupancy grid as a method for modeling and classifying spatial areas according to the time properties of their occupancy. The method extends the idea of occupancy grids[1] by considering occupancy over a number of different timescales. This paper presents the basic formalism and its implementation using planar laser rangefinders. It includes the results of a number of validation experiments, and an experiment in which we demonstrate the ability to locate doors in a real-world setting.
Consistent labeling for multi-camera object tracking
- In Proc. of Int’l Conference on Image Analysis and Processing
, 2005
"... Abstract. In this paper, we present a new approach to multi-camera object tracking based on the consistent labeling. An automatic and reliable procedure allows to obtain the homographic transformation between two overlapped views, without any manual calibration of the cameras. Object’s positions are ..."
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Cited by 9 (3 self)
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Abstract. In this paper, we present a new approach to multi-camera object tracking based on the consistent labeling. An automatic and reliable procedure allows to obtain the homographic transformation between two overlapped views, without any manual calibration of the cameras. Object’s positions are matched by using the homography when the object is firstly detected in one of the two views. The approach has been tested also in the case of simultaneous transitions and in the case in which people are detected as a group during the transition. Promising results are reported over a real setup of overlapped cameras. 1
Design and implementation of ubiquitous smart cameras
- in SUTC ’06: Proceedings of the IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing -Vol 1 (SUTC’06
, 2006
"... Design aspects and software modelling for ubiquitous real-time camera system are described in this paper. We propose system architecture using a network of inexpensive cameras and perform video processing in-network. In general, ubiquitous systems have to perform spatial and temporal calibration in ..."
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Cited by 5 (2 self)
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Design aspects and software modelling for ubiquitous real-time camera system are described in this paper. We propose system architecture using a network of inexpensive cameras and perform video processing in-network. In general, ubiquitous systems have to perform spatial and temporal calibration in advance to determine timing and coordination relationship between sensor nodes, and other application specific design considerations, such as system architecture, distributed software, control authority and communication channel. A methodology for transforming welldesigned single-node algorithm to distributed system is also proposed. Applications for ubiquitous cameras can be modelled as the composition of system finite state machine, functional services and middleware. A service oriented software architecture is proposed to dynamically reconfigure services when system state changes. We have developed a distributed gesture recognition system with true in-network processing to analyze video in real time. By exchanging data and control messages between neighboring sensors, each node can maintain broader view of the environment with integrated video processing results. Our prototype system is built on Windows machines, and uses webcams as sensors and local network as communication channel. 1.
Calibration-free Camera Hand-Over for Fast and Reliable Person Tracking in Multi-Camera Setups
"... Ensembles of multiple (active) cameras yield an important ingredient in modern tracking and surveillance applications. They overcome the limited fields-of-view of single cameras, however, require robust procedures for handing over tracking tasks from one camera to another. In this paper a calibratio ..."
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Cited by 4 (0 self)
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Ensembles of multiple (active) cameras yield an important ingredient in modern tracking and surveillance applications. They overcome the limited fields-of-view of single cameras, however, require robust procedures for handing over tracking tasks from one camera to another. In this paper a calibration-free procedure is proposed that allows for fast and reliable camera handover in Ambient Intelligence (AmI) applications. The approach is based on online acquisition of scenariospecific target models and especially solves the problem of significant changes in object view during handover. Real-world results acquired in an AmI environment prove the effectiveness of our technique. 1.
A System for Automatic Face Obscuration for Privacy Purposes
"... This work proposes a method for automatic face obscuration capable of protecting people’s identity. Since face detection heavily benefits from the possibility to exploit tracking, multi-camera people tracking has been integrated with a face detector based on colour clustering and Hough transform. Mo ..."
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Cited by 3 (0 self)
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This work proposes a method for automatic face obscuration capable of protecting people’s identity. Since face detection heavily benefits from the possibility to exploit tracking, multi-camera people tracking has been integrated with a face detector based on colour clustering and Hough transform. Moreover, the multiple viewpoints provided by multiple cameras are exploited in order to always obtain a good-quality image of the face. The identity of people in different views is kept consistent by means of a geometrical, uncalibrated approach based on homographies. Experimental results show the accuracy of the proposed approach.
A Bayesian hierarchical framework for multitarget labeling and correspondence with ghost suppression over multicamera surveillance system
- IEEE Trans. Autom. Sci. Eng
, 2012
"... Abstract—In this paper, the main purpose is to locate, label, and correspond multiple targets with the capability of ghost suppres-sion over a multicamera surveillance system. In practice, the chal-lenges come from the unknown target number, the interocclusion among targets, and the ghost effect cau ..."
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Cited by 2 (0 self)
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Abstract—In this paper, the main purpose is to locate, label, and correspond multiple targets with the capability of ghost suppres-sion over a multicamera surveillance system. In practice, the chal-lenges come from the unknown target number, the interocclusion among targets, and the ghost effect caused by geometric ambiguity. Instead of directly corresponding objects among different camera views, the proposed framework adopts a fusion-inference strategy. In the fusion stage, we formulate a posterior distribution to indi-cate the likelihood of having some moving targets at certain ground locations. Based on this distribution, a systematic approach is pro-posed to construct a rough scene model of the moving targets. In the inference stage, the scene model is inputted into a proposed Bayesian hierarchical detection framework, where the target la-beling, target correspondence, and ghost removal are regarded as a unified optimization problem subject to 3-D scene priors, target
Multi-Camera Visual Surveillance for Motion Detection, Occlusion Handling, Tracking and Event Recognition 1
, 2008
"... Abstract. This paper presents novel approaches for background modeling, occlusion handling and event recognition by using multi-camera configurations that can be used to overcome the limitations of the single camera configurations. The main novelty in proposed background modeling approach is buildin ..."
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Cited by 2 (0 self)
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Abstract. This paper presents novel approaches for background modeling, occlusion handling and event recognition by using multi-camera configurations that can be used to overcome the limitations of the single camera configurations. The main novelty in proposed background modeling approach is building multivariate Gaussians background model for each pixel of the reference camera by utilizing homography-related positions. Also, occlusion handling is achieved by generation of the top-view via trifocal tensors, as a result of matching over-segmented regions instead of pixels. The resulting graph is segmented into objects after determining the minimum spanning tree of this graph. Tracking of multi-view data is obtained by utilizing measurements across the views in case of occlusions. The last contribution is the classification of the resulting trajectories by GM-HMMs, yielding better results for using together all different view trajectories of the same object. Hence, multi-camera sensing is fully exploited from motion detection to event modeling. 1