5,508 research outputs found

    Semantic Indexing of Sport Program Sequences by Audio-Visual Analysis

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    Semantic indexing of sports videos is a subject of great interest to researchers working on multimedia content characterization. Sports programs appeal to large audiences and their efficient distribution over various networks should contribute to widespread usage of multimedia services. In this paper, we propose a semantic indexing algorithm for soccer programs which uses both audio and visual information for content characterization. The video signal is processed first by extracting low-level visual descriptors from the MPEG compressed bit-stream. The temporal evolution of these descriptors during a semantic event is supposed to be governed by a controlled Markov chain. This allows to determine a list of those video segments where a semantic event of interest is likely to be found, based on the maximum likelihood criterion. The audio information is then used to refine the results of the video classification procedure by ranking the candidate video segments in the list so that the segments associated to the event of interest appear in the very first positions of the ordered list. The proposed method is applied to goal detection. Experimental results show the effectiveness of the proposed cross-modal approach

    Future-Viewer: An Efficient Framework for Navigating and Classifying Audio-Visual Documents

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    In this paper we present an intuitive framework named Future-Viewer, introduced for the effective visualization of spatiotemporal low-level features, in the context of browsing and retrieval of a multimedia document. This tool is used to facilitate the access to the content and to improve the understanding of the semantics associated to the considered multimedia document. The main visualization paradigm employed consists in representing a 2D feature space in which the video document shots are located. The features that characterize the 2D space's axes can be selected by the user. Shots with similar content fall near each other, and the tool offers various functionalities for automatically nding and annotating shot clusters in the feature space. These annotations can also be stored in MPEG7 format. The use of this application to browse the content of few audio-video sequences demonstrate very interesting capabilities

    Efficient Digital Pre-Filtering For Least-Squares Linear Approximation

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    In this paper we propose a very simple FIR pre-filter based method for near optimal least-squares linear approximation of discrete time signals. A digital pre-processing filter, which we demonstrate to be near-optimal, is applied to the signal before performing the usual linear interpolation. This leads to a non interpolating reconstruction of the signal, with good reconstruction quality and very limited computational cost. The basic formalism adopted to design the pre-filter has been derived from the framework introduced by Blu et Unser in [1]. To demonstrate the usability and the effectiveness of the approach, the proposed method has been applied to the problem of natural image resampling, which is typically applied when the image undergoes successive rotations. The performance obtained are very interesting, and the required computational effort is extremely low

    A proposal for Video Signature Tool and Video Fingerprinting

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    In this document we present and evaluate a video signature system, proposed by Signals and Communications Laboratory – Department of Electronic for Automation, University of Brescia (Italy)

    Error Resilience Performance Evaluation of a Distributed Video Codec

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    Distributed Video Coding (DVC), one of the most active research field in the video coding community, is based on the combination of Slepian-Wolf coding techniques with the idea of performing the prediction at the decoder side rather than at the encoder side. Besides its main property, which is flexible allocation of computational complexity between encoder and decoder, the distributed approach has other interesting properties. One of the most promising DVC characteristics is its intrinsic robustness to transmission errors. In this work we have evaluated the error resilience performance of a video codec based on the DVC scheme proposed by Stanford, and we have carried out a preliminary comparison with traditional H.264 encoding, showing that at high error probabilities and high bitrates the distributed approach can also outperform the traditional one

    Individual patient data meta-analysis of randomized controlled trials of community occupational therapy for stroke patients

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    <p><b>Background and Purpose:</b> Trials of occupational therapy for stroke patients living in the community have varied in their findings. It is unclear why these discrepancies have occurred.</p> <p><b>Methods:</b> Trials were identified from searches of the Cochrane Library and other sources. The primary outcome measure was the Nottingham Extended Activities of Daily Living (NEADL) score at the end of intervention. Secondary outcome measures included the Barthel Index or the Rivermead ADL (Personal ADL), General Health Questionnaire (GHQ), Nottingham Leisure Questionnaire (NLQ), and death. Data were analyzed using linear or logistic regression with a random effect for trial and adjustment for age, gender, baseline dependency, and method of follow-up. Subgroup analyses compared any occupational therapy intervention with control.</p> <p><b>Results:</b> We included 8 single-blind randomized controlled trials incorporating 1143 patients. Occupational therapy was associated with higher NEADL scores at the end of intervention (weighted mean difference [WMD], 1.30 points, 95% confidence intervals [CI], 0.47 to 2.13) and higher leisure scores at the end of intervention (WMD, 1.51 points; 95% CI, 0.24 to 2.79). Occupational therapy emphasizing activities of daily living (ADL) was associated with improved end of intervention NEADL (WMD, 1.61 points; 95% CI, 0.72 to 2.49) and personal activities of daily living (odds ratio [OR], 0.65; 95% CI, 0.46 to 0.91), but not NLQ. Leisure-based occupational therapy improved end of intervention NLQ (WMD, 1.96 points; 95% CI, 0.27 to 3.66) but not NEADL or PADL.</p> <p><b>Conclusions:</b> Community occupational therapy significantly improved personal and extended activities of daily living and leisure activity in patients with stroke. Better outcomes were found with targeted interventions.</p&gt
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