Browsing by Author "Athitsos, Vassilis"

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Browsing by Author "Athitsos, Vassilis"

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  • Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2001)
    Ongoing work towards appearance-based 3D hand pose estimation from a single image is presented. A large database of synthetic hand views is generated using a 3D hand model and computer graphics. The views display different ...
  • Rosales, Romer; Athitsos, Vassilis; Sigal, Leonid; Sclaroff, Stan (Boston University Computer Science Department, 2000-12-04)
    A system for recovering 3D hand pose from monocular color sequences is proposed. The system employs a non-linear supervised learning framework, the specialized mappings architecture (SMA), to map image features to likely ...
  • Alon, Jonathan; Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2005-06-03)
    Gesture spotting is the challenging task of locating the start and end frames of the video stream that correspond to a gesture of interest, while at the same time rejecting non-gesture motion patterns. This paper proposes ...
  • Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2001)
    An appearance-based framework for 3D hand shape classification and simultaneous camera viewpoint estimation is presented. Given an input image of a segmented hand, the most similar matches from a large database of synthetic ...
  • Yuan, Quan; Sclaroff, Stan; Athitsos, Vassilis (Boston University Computer Science Department, 2004-11-02)
    In gesture and sign language video sequences, hand motion tends to be rapid, and hands frequently appear in front of each other or in front of the face. Thus, hand location is often ambiguous, and naive color-based hand ...
  • Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2004-02-13)
    This paper introduces an algorithm that uses boosting to learn a distance measure for multiclass k-nearest neighbor classification. Given a family of distance measures as input, AdaBoost is used to learn a weighted distance ...
  • Athitsos, Vassilis; Alon, Jonathan; Sclaroff, Stan; Kollios, George (Boston University Computer Science Department, 2003-11-24)
    This paper introduces BoostMap, a method that can significantly reduce retrieval time in image and video database systems that employ computationally expensive distance measures, metric or non-metric. Database and query ...
  • Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2003-04-01)
    Estimation of 3D hand pose is useful in many gesture recognition applications, ranging from human-computer interaction to automated recognition of sign languages. In this paper, 3D hand pose estimation is treated as a ...
  • Athitsos, Vassilis; Wang, Jingbin; Sclaroff, Stan; Betke, Margrit (Boston University Computer Science Department, 2005-06-13)
    This paper proposes a method for detecting shapes of variable structure in images with clutter. The term "variable structure" means that some shape parts can be repeated an arbitrary number of times, some parts can be ...
  • Athitsos, Vassilis; Alon, Jonathan; Sclaroff, Stan (Boston University Computer Science Department, 2005-03-16)
    Nearest neighbor classification using shape context can yield highly accurate results in a number of recognition problems. Unfortunately, the approach can be too slow for practical applications, and thus approximation ...
  • Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2003-04-01)
    A method is proposed that can generate a ranked list of plausible three-dimensional hand configurations that best match an input image. Hand pose estimation is formulated as an image database indexing problem, where the ...
  • Sigal, Leonid; Sclaroff, Stan; Athitsos, Vassilis (Boston University Computer Science Department, 1999-12-01)
    A novel approach for real-time skin segmentation in video sequences is described. The approach enables reliable skin segmentation despite wide variation in illumination during tracking. An explicit second order Markov model ...
  • La Casica, Marco; Sclaroff, Stan; Athitsos, Vassilis (Boston University Computer Science Department, )
    An improved technique for 3D head tracking under varying illumination conditions is proposed. The head is modeled as a texture mapped cylinder. Tracking is formulated as an image registration problem in the cylinder's ...
  • Athitsos, Vassilis (Boston University Computer Science Department, 2006-06-14)
    Nearest neighbor retrieval is the task of identifying, given a database of objects and a query object, the objects in the database that are the most similar to the query. Retrieving nearest neighbors is a necessary component ...
  • Athitsos, Vassilis; Alon, Joni; Sclaroff, Stan; Kollios, George (Boston University Computer Science Department, 2004-04-07)
    BoostMap is a recently proposed method for efficient approximate nearest neighbor retrieval in arbitrary non-Euclidean spaces with computationally expensive and possibly non-metric distance measures. Database and query ...
  • Wang, Jingbin; Athitsos, Vassilis; Sclaroff, Stan; Betke, Margrit (Boston University Computer Science Department, 2006-10-02)
    Hidden State Shape Models (HSSMs) [2], a variant of Hidden Markov Models (HMMs) [9], were proposed to detect shape classes of variable structure in cluttered images. In this paper, we formulate a probabilistic framework ...
  • Alon, Jonathan; Athitsos, Vassilis; Sclaroff, Stan (Boston University Computer Science Department, 2005-06-03)
    Nearest neighbor classifiers are simple to implement, yet they can model complex non-parametric distributions, and provide state-of-the-art recognition accuracy in OCR databases. At the same time, they may be too slow for ...
  • Athitsos, Vassilis; Hadjieleftheriou, Marios; Kollios, George; Sclaroff, Stan (Boston University Computer Science Department, 2005-03-16)
    A common problem in many types of databases is retrieving the most similar matches to a query object. Finding those matches in a large database can be too slow to be practical, especially in domains where objects are ...
  • Alon, Jonathan; Athitsos, Vassilis; Yuan, Quan; Sclaroff, Stan (Boston University Computer Science Department, 2004-03-08)
    A framework for the simultaneous localization and recognition of dynamic hand gestures is proposed. At the core of this framework is a dynamic space-time warping (DSTW) algorithm, that aligns a pair of query and model ...
  • Sigal, Leonid; Sclaroff, Stan; Athitsos, Vassilis (Boston University Computer Science Department, 2003-03-25)
    A novel approach for real-time skin segmentation in video sequences is described. The approach enables reliable skin segmentation despite wide variation in illumination during tracking. An explicit second order Markov model ...