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Computer and Robot Vision, 2007. CRV '07. Fourth Canadian Conference on

Date 28-30 May 2007

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Displaying Results 1 - 25 of 70
  • Fourth Canadian Conference on Computer and Robot Vision - Cover

    Publication Year: 2007 , Page(s): c1
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  • Fourth Canadian Conference on Computer and Robot Vision - Title page

    Publication Year: 2007 , Page(s): i - iii
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  • Fourth Canadian Conference on Computer and Robot Vision - Copyright

    Publication Year: 2007 , Page(s): iv
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  • Fourth Canadian Conference on Computer and Robot Vision - Table of contents

    Publication Year: 2007 , Page(s): v - x
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  • Preface

    Publication Year: 2007 , Page(s): xi
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  • Committees

    Publication Year: 2007 , Page(s): xii
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  • Extrinsic Recalibration in Camera Networks

    Publication Year: 2007 , Page(s): 3 - 10
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    This work addresses the practical problem of keeping a camera network calibrated during a recording session. When dealing with real-time applications, a robust calibration of the camera network needs to be assured, without the burden of a full system recalibration at every (un)intended camera displacement. In this paper we present an efficient algorithm to detect when the extrinsic parameters of a... View full abstract»

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  • Screen-Camera Calibration using a Spherical Mirror

    Publication Year: 2007 , Page(s): 11 - 20
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (306 KB) |  | HTML iconHTML  

    Developments in the consumer market have indicated that the average user of a personal computer is likely to also own a webcam. With the emergence of this new user group will come a new set of applications, which will require a user-friendly way to calibrate the position of the camera with respect to the location of the screen. This paper presents a fully automatic method to calibrate a screen-cam... View full abstract»

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  • A Simple Operator for Very Precise Estimation of Ellipses

    Publication Year: 2007 , Page(s): 21 - 28
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (455 KB) |  | HTML iconHTML  

    This paper presents a simple linear operator that accurately estimates the position and parameters of ellipse features. Based on the dual conic model, the operator avoids the intermediate stage of precisely extracting individual edge points by exploiting directly the raw gradient information in the neighborhood of an ellipse's boundary. Moreover, under the dual representation, the dual conic can e... View full abstract»

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  • Training Database Adequacy Analysis for Learning-Based Super-Resolution

    Publication Year: 2007 , Page(s): 29 - 35
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (908 KB) |  | HTML iconHTML  

    This paper explores the possibility of assessing the adequacy of a training database to be used in a learning-based super-resolution process. The Mean Euclidean Distance (MED) function is obtained by averaging the distance between each input patch and its closest candidate in the training database, for a series of blurring kernels used to construct the low-resolution database. The shape of that fu... View full abstract»

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  • Extracting Salient Objects from Operator-Framed Images

    Publication Year: 2007 , Page(s): 36 - 43
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (335 KB) |  | HTML iconHTML  

    In images framed by human operators, as opposed to those taken under computer control, the position of objects can be an important clue to saliency. This paper uses the Berkeley image data set to show how locational and photometric information can be combined to extract a probability of saliency for all image pixels. This probability can then be thresholded and segmented to extract compact image r... View full abstract»

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  • Learning Saccadic Gaze Control via Motion Prediciton

    Publication Year: 2007 , Page(s): 44 - 54
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1328 KB) |  | HTML iconHTML  

    This paper describes a system that autonomously learns to perform saccadic gaze control on a stereo pan-tilt unit. Instead of learning a direct map from image positions to a centering action, the system first learns a forward model that predicts how image features move in the visual field as the gaze is shifted. Gaze control can then be performed by searching for the action that best centers a fea... View full abstract»

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  • Efficient camera motion and 3D recovery using an inertial sensor

    Publication Year: 2007 , Page(s): 55 - 62
    Cited by:  Papers (4)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (2823 KB) |  | HTML iconHTML  

    This paper presents a system for 3D reconstruction using a camera combined with an inertial sensor. The system mainly exploits the orientation obtained from the inertial sensor in order to accelerate and improve the matching process between wide baseline images. The orientation further contributes to incremental 3D reconstruction of a set of feature points from linear equation systems. The process... View full abstract»

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  • Can Lucas-Kanade be used to estimate motion parallax in 3D cluttered scenes?

    Publication Year: 2007 , Page(s): 63 - 72
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (386 KB) |  | HTML iconHTML  

    When an observer moves in a 3D static scene, the motion field depends on the depth of the visible objects and on the observer's instantaneous translation and rotation. By computing the difference between nearby motion field vectors, the observer can estimate the direction of local motion parallax and in turn the direction of heading. It has recently been argued that, in 3D cluttered scenes such as... View full abstract»

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  • Local Graph Matching for Object Category Recognition

    Publication Year: 2007 , Page(s): 73 - 80
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (388 KB) |  | HTML iconHTML  

    A novel model for object category recognition in real-world scenes is proposed. Images in our model are represented by a set of triangular labelled graphs, each containing information on the appearance and geometry of a 3-tuple of distinctive image regions. In the learning stage, our model automatically learns a set of codebooks of model graphs for each object category, where each codebook contain... View full abstract»

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  • Efficient Registration of 3D SPHARM Surfaces

    Publication Year: 2007 , Page(s): 81 - 88
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (776 KB) |  | HTML iconHTML  

    We present SHREC, an efficient algorithm for registration of 3D SPHARM (spherical harmonic) surfaces. SHREC follows the iterative closest point (ICP) registration strategy, and alternately improves the surface correspondence and adjusts the object pose. It establishes the surface correspondence by aligning the underlying SPHARM parameterization. It employs a rotational property of the harmonic exp... View full abstract»

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  • Computing View-normalized Body Parts Trajectories

    Publication Year: 2007 , Page(s): 89 - 96
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (982 KB) |  | HTML iconHTML  

    This paper proposes an approach to compute view normalized body part trajectories of pedestrians from monocular video sequences. The proposed approach first extracts the 2D trajectories of both feet and of the head from tracked silhouettes. On that basis, it segments the walking trajectory into piecewise linear segments. Finally, a normalization process is applied to head and feet trajectories ove... View full abstract»

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  • Automated Detection of Mitosis in Embryonic Tissues

    Publication Year: 2007 , Page(s): 97 - 104
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (2978 KB) |  | HTML iconHTML  

    Characterization of mitosis is important for understanding the mechanisms of development in early stage embryos. In studies of cancer, another situation in which mitosis is of interest, the tissue is stained with contrast agents before mitosis characterization; an intervention that could lead to atypical development in live embryos. A new image processing algorithm that does not rely on the use of... View full abstract»

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  • Computer Assisted Detection of Polycystic Ovary Morphology in Ultrasound Images

    Publication Year: 2007 , Page(s): 105 - 112
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (683 KB) |  | HTML iconHTML  

    Polycystic ovary syndrome (PCOS) is an endocrine abnormality with multiple diagnostic criteria due to its heterogenic manifestations. One of the diagnostic criteria includes analysis of ultrasound images of ovaries for the detection of number, size, and distribution of follicles within the ovary. This involves manual tracing and counting of follicles on the ultrasound images to determine the prese... View full abstract»

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  • Automatic Detection and Clustering of Actor Faces based on Spectral Clustering Techniques

    Publication Year: 2007 , Page(s): 113 - 122
    Cited by:  Papers (4)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1158 KB) |  | HTML iconHTML  

    We describe a video indexing system that aims at indexing large video files in relation to the presence of similar faces. The detection of near-frontal view faces is done with a cascade of weak classifier. Face tracking is done through a particle filter and generate trajectories. Face clusters are found based on a spectral clustering approach. We compare the performance of various spectral cluster... View full abstract»

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  • Petri Net-Based Cooperation In Multi-Agent Systems

    Publication Year: 2007 , Page(s): 123 - 130
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (205 KB) |  | HTML iconHTML  

    We present a formal framework for robotic cooperation in which we use an extension to Petri nets, known as workflow nets, to establish a protocol among mobile agents based on the task coverage they maintain. Our choice is motivated by the fact that Petri nets handle concurrency and that goal reachability can be theoretically established. We describe the means by which cooperation is performed with... View full abstract»

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  • Corridor Navigation and Obstacle Avoidance using Visual Potential for Mobile Robot

    Publication Year: 2007 , Page(s): 131 - 138
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (981 KB) |  | HTML iconHTML  

    In this paper, we develop an algorithm for corridor navigation and obstacle avoidance using visual potential for visual navigation by an autonomous mobile robot. The robot is equipped with a camera system which dynamically captures the environment. The visual potential is computed from an image sequence and optical flow computed from successive images captured by the camera mounted on the robot. O... View full abstract»

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  • Energy Efficient Robot Rendezvous

    Publication Year: 2007 , Page(s): 139 - 148
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1024 KB) |  | HTML iconHTML  

    We examine the problem of finding a single meeting location for a group of heterogeneous autonomous mobile robots, such that the total system cost of traveling to the rendezvous is minimized. We propose two algorithms that solve this problem. The first method computes an approximate globally optimal meeting point using numerical simplex minimization. The second method is a computationally cheap he... View full abstract»

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  • Camera Sensor Model for Visual SLAM

    Publication Year: 2007 , Page(s): 149 - 156
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1329 KB) |  | HTML iconHTML  

    In this paper, we present a technique for the construction of a camera sensor model for visual SLAM. The proposed method is an extension of the general camera calibration procedure and requires the camera to observe a planar checkerboard pattern shown at different orientations. By iteratively placing the pattern at different distances from the camera, we can find a relationship between the measure... View full abstract»

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  • Quantitative Evaluation of Feature Extractors for Visual SLAM

    Publication Year: 2007 , Page(s): 157 - 164
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (185 KB) |  | HTML iconHTML  

    We present a performance evaluation framework for visual feature extraction and matching in the visual simultaneous localization and mapping (SLAM) context. Although feature extraction is a crucial component, no qualitative study comparing different techniques from the visual SLAM perspective exists. We extend previous image pair evaluation methods to handle non-planar scenes and the multiple imag... View full abstract»

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