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Petia Radeva, Joan Serrat, & Enric Marti. (1995). A snake for model-based segmentation. In Proc. Conf. Fifth Int Computer Vision (pp. 816–821).
Abstract: Despite the promising results of numerous applications, the hitherto proposed snake techniques share some common problems: snake attraction by spurious edge points, snake degeneration (shrinking and attening), convergence and stability of the deformation process, snake initialization and local determination of the parameters of elasticity. We argue here that these problems can be solved only when all the snake aspects are considered. The snakes proposed here implement a new potential eld and external force in order to provide a deformation convergence, attraction by both near and far edges as well as snake behaviour selective according to the edge orientation. Furthermore, we conclude that in the case of model-based seg mentation, the internal force should include structural information about the expected snake shape. Experiments using this kind of snakes for segmenting bones in complex hand radiographs show a signi cant improvement.
Keywords: snakes; elastic matching; model-based segmenta tion
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Petia Radeva, & Enric Marti. (1995). An improved model of snakes for model-based segmentation. In Proceedings of Computer Analysis of Images and Patterns (pp. 515–520).
Abstract: The main advantage of segmentation by snakes consists in its ability to incorporate smoothness constraints on the detected shapes that can occur. Likewise, we propose to model snakes with other properties that reflect the information provided about the object of interest in a different extent. We consider different kinds of snakes, those searching for contours with a certain direction, those preserving an object’s model, those seeking for symmetry, those expanding open, etc. The availability of such a collection of snakes allows not only the more complete use of the knowledge about the segmented object, but also to solve some problems of the existing snakes. Our experiments on segmentation of facial features justify the usefulness of snakes with different properties.
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Ole Vilhelm-Larsen, Petia Radeva, & Enric Marti. (1995). Guidelines for choosing optimal parameters of elasticity for snakes. In Computer Analysis Of Images And Patterns (Vol. 970, pp. 106–113). LNCS.
Abstract: This paper proposes a guidance in the process of choosing and using the parameters of elasticity of a snake in order to obtain a precise segmentation. A new two step procedure is defined based on upper and lower bounds on the parameters. Formulas, by which these bounds can be calculated for real images where parts of the contour may be missing, are presented. Experiments on segmentation of bone structures in X-ray images have verified the usefulness of the new procedure.
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Ole Larsen, Petia Radeva, & Enric Marti. (1995). Bounds on the optimal elasticity parameters for a snake. Image Analysis and Processing, , 37–42.
Abstract: This paper develops a formalism by which an estimate for the upper and lower bounds for the elasticity parameters for a snake can be obtained. Objects different in size and shape give rise to different bounds. The bounds can be obtained based on an analysis of the shape of the object of interest. Experiments on synthetic images show a good correlation between the estimated behaviour of the snake and the one actually observed. Experiments on real X-ray images show that the parameters for optimal segmentation lie within the estimated bounds.
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Jordi Vitria, C. Gratin, D. Seron, & F. Moreso. (1995). Morphological image analysis for quantification of renal damage.
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Joan Serrat. (1995). Aplicacion del analisis de imagenes en radiologia..
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A. Martinez, & Jordi Vitria. (1995). Designing and Implementing Real Walking Agents using Virtual Environments.
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A. Martinez, & Jordi Vitria. (1995). A Development Plataform for Autonomous Agents. ASI–AA–95 – Practice and Future of Autonomous Agents., .
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A. Martinez, Jordi Vitria, & S. Sampayo. (1995). Atlas: a Hexapod driven by a Neural Network..
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Petia Radeva, & Enric Marti. (1995). Facial Features Segmentation by Model-Based Snakes..
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Antonio Lopez, & Joan Serrat. (1995). Image Analysis through Surface Geometric Descriptors.
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Jordi Vitria, & J. Llacer. (1995). Recovering brightness and depth from focus using the Expectation-Maximization Algorithm..
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D. Seron, F. Moreso, C. Gratin, & Jordi Vitria. (1995). Morphological Granulometries and Quantification of Interstitial Chronic Renal Damage.
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V. Valev, & Petia Radeva. (1995). ECG Recognition by Non-Reducible Descriptors..
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V. Valev, & Petia Radeva. (1995). Constructing Quantitative Non-Reducible Descriptors..
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