Fast Approximate Energy Minimization via Graph Cuts M.S. Student, Hee-Jong Hong May 29, 2013
2
Introduction
Previous Works
Proposed Method
Experiment
Conclusion
Contents
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
3
Local Method
– Sum of Squared Differences
– Sum of Absolute Differences
– Zero-mean Normalized Cross-Correlation
Global Method
– Dynamic Programming (One Dimensional Problem)
– Graph Cuts (Every Epipolar Line)
Introduction
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
4
Global Optimization
Introduction
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
Sum Of Local Energy Sum Of Global Energy
(a)
(b)
0
4
0 + K/2 + K/2 = K
V(a,b) = V(b,c) = K/2
V(a,c) = K
(d)
4 + 0 + 0 = 4
Dynamic Programming
Introduction
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
5
1 2 3 41
2
3
4
Disparity
A Image Row
Energy Minimization
Introduction
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
6
Another global approach to improve qual-ity of correspondences
Assumption: disparities vary (mostly) smoothly
Minimize energy function:Edata+lEsmoothness
Edata: how well does disparity match data
Esmoothness: how well does disparity matchthat of neighbors – regularization
Energy Definition in Stereo
Introduction
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
7
),(),(),,( ydxyxdyxD JI
similar)something(or
d2 and d1 labels with pixelsadjacentofcost
21
21 ),(
dd
ddV
)2,2(),1,1(
2,21,1),(
, ),(),,(})({yxyxneighbors
yxyxyx
yx ddVdyxDdE
Max Flow / Min Cut
Previous Works
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
8
“source”
A graph with two terminals
S T
“sink”
Previous Works
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
Labeling– For each pixel, either the F or G edge has to be cut– Only one edge label per pixel can be cut (otherwise
could be added
B
F
Proposed Method
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
Swap Move & Expansion Move
Energy Definition
– Data Term :
– Smoothness Term : Static Cues (Weighted Potts)
Experiment
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
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Static Cues
Experiment
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
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Potts
Static Cues
0?1?unkown
Give Higher Smoothness Factor to Continues Intensity
1Pixel Move
Experiment
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
18
Swap Move
Expansion Move
Experiment
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
19
Normalized Corr
&
Annealling
Expansion Move
&
Swap Move
Conclusion
Visual Object Tracking using Adaptive Correlation Filters [CVPR 2010]
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Performs well on a variety of computer vision prob-
lems
– Image Restoration, Stereo, and Motion
Very Faster than Annealing