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Object Segmentation in Video: A Hierarchical Variational Approach for Turning Point Trajectories into Dense Regions. 层次化变分法用于稠密的视频运动分割 Peter Ochs and Thomas Brox University of Freiburg, Germany ICCV 2011. Thomas Brox, Professor in University of Freiburg, Germany Experience:
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Object Segmentation in Video: A Hierarchical Variational Approach for Turning Point Trajectories into Dense Regions 层次化变分法用于稠密的视频运动分割 Peter Ochs and Thomas Brox University of Freiburg, Germany ICCV 2011
Thomas Brox, Professor in University of Freiburg, Germany Experience: Received PhD from Saarland University in 2005. 2005-2007 Post Doctor in Born University. 2007-2008 Temporary Professor in University of Dresden. 2008-2010 Post Doctor in UC Berkerley with J. Malik. Main Interests: Optical Flow, Segmentation, Human Motion Representative Work: Brox Optical Flow(ECCV’04 best paper) LDOF (PAMI’10) Segmentation (ECCV’10)
Video Segmentation • Two Tasks • Shots Segmentation • Spatial-Temperal Cues Segmentation • Motion Segmentation
Motion Segmentation • Optical flow based • Earlier Methods • Layers • Feature trajectory based • Most Popular in the last 10 years • Utilize 3D Motion • Related to Subspace Clustering • Hybrid methods using both motion and static cues
Sparse Point Segmentation (1/6) • Optical Flow to obtain long-term point Trajectories Thomas Brox and Jitendra Malik, Object Segmentation by Long Term Analysis of Point Trajectories, ECCV 2010
Sparse Point Segmentation (2/6) • Similarity Definition
Sparse Point Segmentation (3/6) • Similarity Definition
Sparse Point Segmentation (4/6) • Standard Spectral Clustering
Sparse Point Segmentation (5/6) • Spectral Clustering with Spatial Regularity • Automatically determine cluster number
Sparse Point Segmentation (6/6) • Main Contribution • Very Sparse Feature Points 0.01%-> Sparse points (3%)
Solution (1/2) Euler-LagrangeEquation:
Solution (2/2) Euler-LagrangeEquation: Successive over-relaxation: solve AX=B, where A = D - L - U by
Why Multi-level continuous model? • Multi-level • Information can take a shortcut via a coarser level where this noise has been removed. • Continuous • Less block artifacts
Solution Euler-LagrangeEquation: k>0 k=0
Summary • Combining Motion Cues and Static Cues • Propose a Multi-level Variational Method