Active Contours and their Utilization at Image SegmentationAuthorMarin BakoSource 5th Slovakian-Hungarian Joint Symposium on Applied Machine Intelligence and Informatics January 25-26, 2007Speaker Cheng-Jung WuAdvisor Ku-Yaw Chang

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OutlineBackgroundBasic Types of Deformable ModelsBasic DefinitionConclusion

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BackgroundAn active contourImage segmentationiterationresultinitialization

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BackgroundAn active contourEnergy minimizing splineFlexibile curve (or surface)A set of control pointsSequence of each otherStraight linesAn interactive processThe user an initial contourThe intended shape

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OutlineBackgroundBasic Types of Deformable ModelsBasic DefinitionConclusion

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Basic Types of Deformable ModelsDeformable modelsParametricGeometricThe parametric deformable modelsCurves and surfacesDuring deforming explicitly in parametric formHelp of some of the following formulationsThe formulation of minimizing energyThe formulation of dynamic force

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Basic Types of Deformable ModelsThe formulation of minimizing energyMinimizationInternaltension or smoothness of contourImagehigh gradient edgeTotal energy minimizationInternal = external energiesThe formulation of dynamic forceHelp of force formulationDynamic problemExternal and imageE.g.a negative gradient of potential energy function

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Basic Types of Deformable ModelsThe geometric deformable modelsElegant solutionParametric deformable modelsCurves and surfaces evolutionGeometric criteriaThe evolution independentParametrizationThe curves and surfaces generatingThe level set of a multidimensional functionTopological changesEasy to control

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OutlineBackgroundBasic Types of Deformable ModelsBasic DefinitionConclusion

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Basic DefinitionSnakeInternalElasticcurve compactfirst-orderBend limit its very acuminous deflectionssecond-orderoriginalelastic12ABC

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Basic Definitionbendelasticoriginal

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Basic DefinitionImageLineedgescale spaceExternalThe curve towards the objects borders

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OutlineBackgroundBasic Types of Deformable ModelsBasic DefinitionConclusion

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ConclusionArtificial vs. Real512515ArtificialinitializationRealinitialization

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ConclusionThe number of iterationsThe size of the scanned surroundingsDisadvantagesThe initial points of the contourDependencyType of the pictureComputing difficultyPossibleBy the use of less accurate but satisfactory methods

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The EndThanks ~

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