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Towards Unsupervised Whole-Object Segmentation: Combining Automated Matting with Boundary Detection. Andrew N. Stein∗ Thomas S. Stepleton Martial Hebert The Robotics Institute, Carnegie Mellon University Reporter: Hsieh Chia-Hao Date: 2009/09/28. Introduction.
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Towards Unsupervised Whole-Object Segmentation:Combining Automated Matting with Boundary Detection Andrew N. Stein∗ Thomas S. Stepleton Martial Hebert The Robotics Institute, Carnegie Mellon University Reporter: Hsieh Chia-Hao Date: 2009/09/28
Introduction • Towards Unsupervised Whole-Object Segmentation: Combining Automated Matting with Boundary Detection
Outline • Segmentation “Hints” via Multiple Mattes • α-Matting • Multiple Mattes Affinities • Detecting Boundary Fragments • Image Segmentation by Ncuts • Evaluating Object Segmentations • Experiments
α-Matting Multiple Mattes • α-Matting • Multiple Mattes Affinities Pixel OR super-pixels
Detecting Boundary Fragments • Incorporating local, instantaneous motion estimates when short video clips are available • Over-segments a scene into a few hundred “super-pixels” using a watershed-based approach • Learned classifiers and inference on a graphical model boundary probabilities (weight for W)
Image Segmentation by Ncuts • Given pair-wise affinity matrix A • Use spectral clustering according to the Normalized Cut Criterion • Produce an image segmentation with K segments • K is variable
Evaluating Object Segmentations • Consistency • Efficiency R = {A, B, C, . . . } ⊆S is a subset of segments from a given (over-)segmentation S
Experiments bottom-up perspective
Discussion • Promising results for use in subsequent work on unsupervised object discovery or scene understanding