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Introduction
Adrien Bartoli
ALCoV – ISIT
Université d’Auvergne
Clermont-Ferrand, France
Fourth Tutorial on Computer Vision in a Nonrigid World ICCV’11, Barcelona, Spain – octobre 6, 2011
Lourdes Agapito, Adrien Bartoli, Alessio Del Bue
Millennia
Century
Decades
“Vision is the act of knowing what is where by looking.”
- Aristotle
Object detection Person detection Person recognition
Tob
y
Ad
rien
Ab
ed
Jae-Hak
Florian
Image Understanding in Computer Vision
Measurements
“Vision is the act of knowing what is where by looking.”
- Aristotle
Measurements
3D Computer Vision
Depth map Partial 3D surface
Real world
A General Sketch of Visual Process
Tob
y
Ad
rien
Ab
ed
Jae-Hak
Florian
Image Formation
Shape-from-X: Inversing Image Formation
?
The X of Shape-from-X
Shading Focus Shadow
Texture Shading+specularity
Silhouette Occlusion
… and more!
Scene Priors
Shape priors – often statistical
→ A kettle is rigid
→ Pretrained models: I saw faces before, I learnt their shape
Deformation priors – often physical
→ Untrained models: the shape is structured
→ A piece of paper is isometric and developable
→ A face is quasi-isometric
= 𝑓( ) From [Blanz and Vetter, PAMI’03]
= 𝑓( )
Real world
A Sketch of the Current Visual Process in SfX
Tob
y
Ad
rien
Ab
ed
Jae-Hak
Florian
Using Multiple-Views
Photometric stereo
Shape-from-Motion - SfM
Image formation
Stereovision Monovision
Are Multiple Views Always Enough?
The answer depends on the scene prior
Rigid Deformable
In general, yes No general answer
State of research: mature State of research: open
Rigid SfM has Two Main Steps
Image registration Shape inference
Registered images with matched keypoints
Non-Rigid SfM / Deformable SfM
Image registration Shape inference
Registered images with visualization grid
Template-Based Deformable 3D Reconstruction
Image
registration
template
Shape
inference
Tutorial Roadmap
• Introduction
1. Deformable Image Registration – Feature-based – Pixel-based
2. Template-Based Deformable Shape Inference – Isometric surfaces – Elastic surfaces
3. Non-Rigid Structure-from-Motion – The Low-Rank Shape Model – Alternative Models
• Conclusion
+
… …
Mo
rnin
g M
orn
ing
Aft
ern
oo
n
Introduction
Adrien Bartoli
ALCoV – ISIT
Université d’Auvergne
Clermont-Ferrand, France
Fourth Tutorial on Computer Vision in a Nonrigid World ICCV’11, Barcelona, Spain – octobre 6, 2011
Lourdes Agapito, Adrien Bartoli, Alessio Del Bue