Search results for "Rotation invariance"

showing 3 items of 3 documents

Keypoint descriptor matching with context-based orientation estimation

2014

Abstract This paper presents a matching strategy to improve the discriminative power of histogram-based keypoint descriptors by constraining the range of allowable dominant orientations according to the context of the scene under observation. This can be done when the descriptor uses a circular grid and quantized orientation steps, by computing or providing a global reference orientation based on the feature matches. The proposed matching strategy is compared with the standard approaches used with the SIFT and GLOH descriptors and the recent rotation invariant MROGH and LIOP descriptors. A new evaluation protocol based on an approximated overlap error is presented to provide an effective an…

GLOHComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONScale-invariant feature transformContext basedReference orientationImage descriptorLIOPDiscriminative modelMROGHHistogramKeypoint matchingSIFTComputer Science::MultimediaComputer visionInvariant (mathematics)MathematicsDominant orientationSettore INF/01 - Informaticabusiness.industryPattern recognitionGridLocal featureRotation invarianceComputer Science::Computer Vision and Pattern RecognitionSignal ProcessingImage descriptors; Local features; Dominant orientation; Rotation invariance; Keypoint matching; SIFT; LIOP; MROGHComputer Vision and Pattern RecognitionArtificial intelligencebusiness
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Extending the sGLOH descriptor

2015

This paper proposes an extension of the sGLOH keypoint descriptor [3] which improves its robustness and discriminability. The sGLOH descriptor can handle discrete rotations by a cyclic shift of its elements thanks to its circular structure, but its performance can decrease when the keypoint relative rotation is in between two sGLOH discrete rotations. The proposed extension couples together two sGLOH descriptors for the same patch with different rotations in order to cope with this issue and it can be also applied straightly to the sCOr and sGOr matching strategies of sGLOH. Experimental results show a consistent improvement of the descriptor discriminability, while different setups can be …

Keypoint descriptorMatching (graph theory)Settore INF/01 - InformaticaComputer scienceGLOHStructure (category theory)Scale-invariant feature transformSGLOHExtension (predicate logic)Keypoint descriptor image matching rotation invarianceRunning timeTask (project management)Robustness (computer science)SIFTMatchingAlgorithm
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Multivariate nonparametric tests in a randomized complete block design

2003

AbstractIn this paper multivariate extensions of the Friedman and Page tests for the comparison of several treatments are introduced. Related unadjusted and adjusted treatment effect estimates for the multivariate response variable are also found and their properties discussed. The test statistics and estimates are analogous to the traditional univariate methods. In test constructions, the univariate ranks are replaced by multivariate spatial ranks (J. Nonparam. Statist. 5 (1995) 201). Asymptotic theory is developed to provide approximations for the limiting distributions of the test statistics and estimates. Limiting efficiencies of the tests and treatment effect estimates are found in the…

Multivariate Friedman testStatistics and ProbabilityMultivariate statisticsNumerical AnalysisMultivariate analysisUnivariateNonparametric statisticsMultivariate normal distributionPitman efficiencyRotation invarianceMultivariate analysis of varianceFriedman testAffine invarianceStatisticsTest statisticSpatial rankStatistics Probability and UncertaintyMultivariate Page testMathematicsJournal of Multivariate Analysis
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