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Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Hannover, 2010-02-23
Image Understanding withOrganic Computing
Rolf P. Wurtz
Ruhr-Universitat BochumInstitut fur Neuroinformatik
http://www.neuroinformatik.rub.derolf.wuertz@neuroinformatik.rub.derolf.wuertz@organic-computing.org
OverviewNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
• Introduction
• Problem of image understanding
• Controlled generalization in face recognition
• General object recognition
• Learning of articulated models
• Where to go from here
Complexity problemsNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
• Artificial systems are rapidly getting too complex to understand
• Desirable are complex systems with trivial interfaces
• This requires restrictions on possible behaviors
• This asks for self-organization
Image understanding . . .Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
. . . means establishing a symbolic description.
Image understanding . . .Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
. . . in the brain is done under additional assumptions.
Image understanding . . .Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
. . . requires extensive world knowledge.
Image understanding . . .Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
. . . has a local-global problem.
Face recognitionNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
= 6=
Different situations yield very different images.
Invariance problemNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
All the same?
Invariance . . .Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
6 6= 6
. . . is task-dependent.
List of tasksNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
• We do need a formal model of images, but we don’t have any
• We do not even have a formalization of the problem
• Required is an imitation of human capability
• Identify constraints of visual data autonomously
• Learn computer vision routines from examples
• Start a positive feedback loop of learning vision
• Control generalization
Controlled generalizationNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
• Neural networks learn complicated functions from examples
• They can generalize, but not always in the desired way
• Visual invariances must be built in explicitly(Neocognitron, Convolutional NN, . . . )
• Exception: Slow feature analysis (Wiskott & Sejnowski, 2002)
• Goal: Learn generalization dimensions from examples!
Bunch GraphsNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
image graph
general facebunch graph Gabor wavelet jet
bunch of jets
a: b: c: Wiskott et al., 1997
Graph similarityNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
• Jet similarity function SJ
• Probe graph P with N nodes Pn
• Gallery graphs Gg with N nodes Gg,n each
grec = arg maxg
1
N
N∑n=1
SJ(Pn, Gg,n) .
Face GraphsNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
Pose VariationNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
PM+45 PM+00 PM−45
Pose VariationNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
Probe Gallery
Similarity?
Gg P
......
Rank CorrelationNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
ModelProbe Gallery
SP SG
π = [7, 3, 9, . . .] γ = [7, 9, 3, . . .]
γ = [2, 1, 35, . . .]
......
......
Neural rank list similarityNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
aj wjE
I
E =
K∑j=1
exp
(−order(aj)
λ
)wj
wj =1
Kexp
(−order(bj)
λ
)
Thorpe et al., 2001
Neural rank list similarityNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
π(m)
wm,g
Ag
wm,g =1
NMexp
(−γg(m)
λ
)Ag =
∑m
exp
(−π(m)
λ
)wm,g
=1
NM
∑m
exp
(−π(m) + γg(m)
λ
)= Sneural(γg, π)
grec = arg maxg
1
N
∑n
Sneural(γg,n, πn)
Muller and Wurtz, ICANN 2009
Face recognition Mainz Hbf.Neuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
CAS-PEAL DatabaseNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
PM+45 FM+00 FM−45 FM−90
PM+00 FD+00 FD−45 FD−90
PM−45 FU+00 FU−45 FU−90
Rank Correlation: ResultsNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
Pose Illumination
Recognition percentage with given situation 99.02 89.01
Percentage of correct situation estimation 99.89 ± 0.09 91.96 ± 0.89
Recognition percentage with automaticallydetermined situation
97.75 ± 0.50 89.97 ± 1.36
Best recognition percentage reported indatabase description
71 51
Rank Correlation: Early stoppingNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
0
0.2
0.4
0.6
0.8
1
0 20 40 60 80 100
Rec
ogni
tion
rate
Spike number
poseillumination
Thanks toNeuroinformatik / Ruhr-Universitat Bochum
Rolf P. Wurtz
Image Understanding with Organic Computing Hannover, 2010-02-23
Marco Muller Rank correlation memoryGunter Westphal Object recognitionThomas Walther Body tracking
Manuel Gunter Statistical face recognitionMarkus Lessmann Scene analysisOliver Lomp Neuronal dynamicsMathis Richter Clustering of image patchesGuillermo Donatti Object memory, Neural Map
DFG, EU, NRW Funding
All of you Attention
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