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P. Arbelaez, M. Maire, C. Fowlkes, J. Malik. Contour Detection and Hierarchical image Segmentation. IEEE Trans. on PAMI , 2011.

 

CONTOUR DETECTION AND HIERARCHICAL IMAGE SEGMENTATION

Student: Hsin-Min ChengAdvisor: Sheng-Jyh Wang

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Outline

Introduction Contour Detection Hierarchical Segmentation Results Conclusion

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Introduction

Original Image Contour

Contour

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Introduction

Original Image Segmentation

Segmentation

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Introduction From Contour to Segmentation

Original Image SegmentationContour

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Introduction Goal

Contour Detection Hierarchical Segmentation from Contours

Original Image SegmentationContour

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Outline

Introduction Contour Detection Hierarchical Segmentation Results Conclusion

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Contour Detection

1. Learn local boundary cues 2. Global framework to capture

closure, continuity3. Local Cues and global cues

combination

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Learn local boundary cues

Image Local Boundary Cues

Model

BrightnessColorTexture

Cue Combination

Contour Detection

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Learn local boundary cues Brightness L*a*b* colorspace

Color L*a*b* colorspace

Texture Convolve with 17 filters

Filters for creating textons

Contour Detection

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Learn local boundary cues Oriented gradient of histograms Example

Gradient magnitude G at location(x, y)

Three scales of r

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Contour Detection

ure ]2 , ,2

[

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Learn local boundary cues Local Cues Combination

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Contour Detection

ure ]2 , ,2

[ r

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Global framework to capture closure, continuityContour Detection

V: image pixels

E: connections between pairs of nearby pixels

=>Build a weighted graph G=(V,E) from image

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Global framework to capture closure, continuityContour Detection

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Local Cues and global cues combinationContour Detection

Local Cues Global cues

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Outline

Introduction Contour Detection Hierarchical Segmentation Results Conclusion

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Hierarchical Segmentation Multiple Segmentations

Fixed resolution

Hierarchy of Segmentations Flexible resolution adjustment

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Hierarchical Segmentation1. From contours to segmentation2. Hierarchical segmentation by

iterative merging

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Hierarchical Segmentation From contours to segmentation

Watershed Transform Concept

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Hierarchical Segmentation From contours to segmentation

Watershed Transform Example

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Hierarchical Segmentation From contours to segmentation

Watershed Transform

Boundary strength ArtifactsWeight each arc

Hierarchical Segmentation From contours to segmentation

Oriented Watershed Transform

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WTOWT

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Hierarchical Segmentation Hierarchical segmentation by iterative

merging Hierarchical segmentation

Example

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Brief SummaryOriginal Image

- Local cues - Global cues

Oriented Gradientof histograms

Contour

Oriented Watershed Transform

Iterative Merging

Hierarchical Segmentation

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Outline

Introduction Contour Detection Hierarchical Segmentation Results Conclusion

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Result

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Result

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Result

Evaluation of segmentation algorithmsEvaluation of contour detector

BSDS300 Dataset

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Outline

Introduction Contour Detection Hierarchical Segmentation Results Conclusion

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Conclusion A high performance contour detector, combining

local and global image information

A method to transform any contour detector signal into a hierarchy of regions while preserving contour quality

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Reference P. Arbelaez, M. Maire, C. Fowlkes and J. Malik. Contour Detection

and Hierarchical Image Segmentation. IEEE TPAMI, Vol. 33, No. 5, pp. 898-916, May 2011

P. Arbelaez, M. Maire, C. Fowlkes and J. Malik. From Contours to Regions: An Empirical Evaluation. In CVPR 2009.

P. Arbelaez and L. Cohen. Constrained Image Segmentation from Hierarchical Boundaries. In CVPR 2008.