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dc.contributor.authorRomberg, Justin
Wakin, Michael
Choi, Hyeokho
Baraniuk, Richard G.
dc.creatorRomberg, Justin
Wakin, Michael
Choi, Hyeokho
Baraniuk, Richard G.
dc.date.accessioned 2007-10-31T01:02:53Z
dc.date.available 2007-10-31T01:02:53Z
dc.date.issued 2003-08-01
dc.date.submitted 2003-08-01
dc.identifier.urihttp://hdl.handle.net/1911/20301
dc.description Conference Paper
dc.description.abstract In the last few years, it has become apparent that traditional wavelet-based image processing algorithms and models have significant shortcomings in their treatment of edge contours. The standard modeling paradigm exploits the fact that wavelet coefficients representing smooth regions in images tend to have small magnitude, and that the multiscale nature of the wavelet transform implies that these small coefficients will persist across scale (the canonical example is the venerable zero-tree coder). The edge contours in the image, however, cause more and more large magnitude wavelet coefficients as we move down through scale to finer resolutions. But if the contours are smooth, they become simple as we zoom in on them, and are well approximated by straight lines at fine scales. Standard wavelet models exploit the grayscale regularity of the smooth regions of the image, but not the geometric regularity of the contours. In this paper, we build a model that accounts for this geometric regularity by capturing the dependencies between complex wavelet coefficients along a contour. The Geometric Hidden Markov Tree (GHMT) assigns each wavelet coefficient (or spatial cluster of wavelet coefficients) a hidden state corresponding to a linear approximation of the local contour structure. The shift and rotational-invariance properties of the complex wavelet transform allow the GHMT to model the behavior of each coefficient given the presence of a linear edge at a specified orientation --- the behavior of the wavelet coefficient given the state. By connecting the states together in a quadtree, the GHMT ties together wavelet coefficients along a contour, and also models how the contour itself behaves across scale. We demonstrate the effectiveness of the model by applying it to feature extraction.
dc.language.iso eng
dc.subjectWavelets
edges
geometry
feature extraction
dc.subject.otherWavelet based Signal/Image Processing
dc.title A Geometric Hidden Markov Tree Wavelet Model
dc.type Conference paper
dc.date.note 2003-10-02
dc.citation.bibtexName inproceedings
dc.date.modified 2006-06-05
dc.contributor.orgDigital Signal Processing (http://dsp.rice.edu/)
dc.subject.keywordWavelets
edges
geometry
feature extraction
dc.citation.location San Diego, CA
dc.citation.conferenceName International Symposium on Optical Science and Technology
dc.type.dcmi Text
dc.type.dcmi Text


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  • DSP Publications [508]
    Publications by Rice Faculty and graduate students in digital signal processing.
  • ECE Publications [1214]
    Publications by Rice University Electrical and Computer Engineering faculty and graduate students

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