Produit T., Tuia D. LaSIG, EPFL 26-Oct-12 1 OGRS 2012, - - PowerPoint PPT Presentation

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produit t tuia d lasig epfl 26 oct 12 1 ogrs 2012 yverdon

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Laboratoire de systmes dinformation gographique LaSIG An open monoplotter to register landscape oblique images and generate their synthetic model. Produit T., Tuia D. LaSIG, EPFL 26-Oct-12 1 OGRS 2012, Yverdon-les-Bains, Produit T.

SLIDE 1

Laboratoire de systèmes d’information géographique LaSIG

An open monoplotter to register landscape oblique images and generate their synthetic model.

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 1

Produit T., Tuia D. LaSIG, EPFL

SLIDE 2

Laboratoire de systèmes d’information géographique LaSIG

A monoplotter is a software which links pixel of an image with its

3D world coordinates.

What do you need?

– Camera coordinate – Camera orientation – Camera intrinsics – DEM

Why? Our research focuses on the automatic pose estimation of

landscape images.

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 2

Introduction

Monoplotter !?

SLIDE 3

Laboratoire de systèmes d’information géographique LaSIG

Involved technologies
Processing

– Image registration (co-linearity) – Z-buffer computation – Functionalities

Case studies

– Aletsch glacier – Chateau-d’Oex postcard collection

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 3

Introduction

Plan

SLIDE 4

Laboratoire de systèmes d’information géographique LaSIG

Involved technologies

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 4

Technologies

SLIDE 5

Laboratoire de systèmes d’information géographique LaSIG

Processing

Image registration:

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 5

Processing

SLIDE 6

Laboratoire de systèmes d’information géographique LaSIG

Involved technologies

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 6

Technologies

SLIDE 7

Laboratoire de systèmes d’information géographique LaSIG

Processing

Z-buffer:

Computer graphics technology used to render synthetic

images.

3D objects are modeled with geometric primitives (Triangle

Irregular Network)

Primitives are projected in the screen plan
And rasterized
Closest pixels are displayed

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 7

Processing

SLIDE 8

Laboratoire de systèmes d’information géographique LaSIG

Processing

Ortho-rectification:

During z-buffering, each pixel in the image obtains a 3D world

coordinate.

Intensity values at each point of a regular grid are interpolated.

Synthetic images are generated by coloring z-buffer with the real

rtho-image

GIS vectors are projected in the image plane using colinearity equations Vectors drawn in the image are projected in the map

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 8

Processing

SLIDE 9

Laboratoire de systèmes d’information géographique LaSIG

Aletsch glacier

What happened during the last century?

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 9

Library of Congress, View of Switzerland , ~1890-1900, http://www.loc.gov/pictures/

Case Studies

SLIDE 10

Laboratoire de systèmes d’information géographique LaSIG

Aletsch glacier

What happened during the last century?

Re-photography
Widely used to show landscape change

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 10

Case Studies

SLIDE 11

Laboratoire de systèmes d’information géographique LaSIG

Aletsch glacier

1. Ground Control Points Digitization
> Camera pose is computed

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 11

Case Studies

SLIDE 12

Laboratoire de systèmes d’information géographique LaSIG

Aletsch glacier

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 12

1. Synthetic image computation
2. Analysis

Profil Δ Horizontal [m] Δ Vertical [m] A 311 82 B 191 120 C 202 83 D 130 44 Case Studies

SLIDE 13

Laboratoire de systèmes d’information géographique LaSIG

Château-d’Oex, ski resort

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 13

Collection of ancient postcards
Assessment of the evolution of landscape
Oblique aerial images

Acm – EPFL, fonds Perrochet – Pleinciel SA , ~1960.

Case Studies

SLIDE 14

Laboratoire de systèmes d’information géographique LaSIG

Château-d’Oex, ski resort

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 14

How did the builded area grow? 1. Orthorectified image computation 2. Augmented image computation

Case Studies

SLIDE 15

Laboratoire de systèmes d’information géographique LaSIG

Château-d’Oex, ski ressort

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 15

A second overlapping postcard?
Computer vision feature detectors / descriptors are able to detect

matches

SURF features SURF matching

Case Studies

SLIDE 16

Laboratoire de systèmes d’information géographique LaSIG

Château-d’Oex, ski ressort

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 16

Automatic pose estimation of the second camera RANSAC to deptict outliers:

4 correspondences are picked

randomly,

A camera pose is computed,
If a sufficiently high ratio of other

correspondences match with this pose, the pose is kept in memory,

Until a «better» one is found.

SURF matching RANSAC computation Visual quality assessment

Case Studies

SLIDE 17

Laboratoire de systèmes d’information géographique LaSIG

Conclusion

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 17

Registration of oblique image has several applications:

– Ancient and non-photogrammetric image valuation – Landscape survey with terrestrial images – Augmented reality applications

EFLUM – EPFL, 2012.

Conclusion

SLIDE 18

Laboratoire de systèmes d’information géographique LaSIG

Conclusion

26-Oct-12 OGRS 2012, Yverdon-les-Bains, Produit T. 18

Why open? You just can’t avoid it!

Most computer vision libraries are open
Multiple softwares interaction (GIS, Computer Vision,

Image Processing, Scientific computing)

Interaction with other labs and students

An open monoplotter to register landscape oblique images and generate their synthetic model.

Produit T., Tuia D. LaSIG, EPFL

3D world coordinates.

– Camera coordinate – Camera orientation – Camera intrinsics – DEM

landscape images.

Introduction

Monoplotter !?

– Image registration (co-linearity) – Z-buffer computation – Functionalities

– Aletsch glacier – Chateau-d’Oex postcard collection

Introduction

Plan

Involved technologies

Technologies

Processing

Image registration:

Processing

Involved technologies

Technologies

Processing

Z-buffer:

images.

Irregular Network)

Processing

Processing

Ortho-rectification:

coordinate.

Synthetic images are generated by coloring z-buffer with the real

GIS vectors are projected in the image plane using colinearity equations Vectors drawn in the image are projected in the map

Processing

Aletsch glacier

What happened during the last century?

Case Studies

Aletsch glacier

What happened during the last century?

Case Studies

Aletsch glacier

Case Studies

Aletsch glacier

Profil Δ Horizontal [m] Δ Vertical [m] A 311 82 B 191 120 C 202 83 D 130 44 Case Studies

Château-d’Oex, ski resort

Case Studies

Château-d’Oex, ski resort

How did the builded area grow? 1. Orthorectified image computation 2. Augmented image computation

Case Studies

Château-d’Oex, ski ressort

matches

Case Studies

Château-d’Oex, ski ressort

Automatic pose estimation of the second camera RANSAC to deptict outliers:

randomly,

correspondences match with this pose, the pose is kept in memory,

Case Studies

Conclusion

– Ancient and non-photogrammetric image valuation – Landscape survey with terrestrial images – Augmented reality applications

Conclusion

Conclusion

Why open? You just can’t avoid it!

Image Processing, Scientific computing)

timothee.produit@epfl.ch http://lasig.epfl.ch

Conclusion