Change search
ReferencesLink to record
Permanent link

Direct link
Multi-scale feature tracking and motion estimation
KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
1999 (English)Doctoral thesis, monograph (Other scientific)
Abstract [en]

This thesis studies the problems of feature tracking and motion estimation and

presents an application of these concepts to human-computer interaction. The

presentation is divided into three parts.

The first part addresses feature tracking in a multi-scale context. Features

in an image appear at different scales, and these scales can be expected to

change over time due to the size variations that occur when objects move relative

to the camera. A scheme for feature tracking is presented, which incorporates

a mechanism for automatic scale selection and it is argued that

such a mechanism is necessary to handle size variations over time. Experiments

demonstrate how the proposed scheme is robust to size variations in

situations where a traditional fixed scale tracker fails. This leads to extended

feature trajectories, which are valuable for motion and structure estimation.

It is also shown how an object representation suitable for tracking can be

built in a conceptually simple way as a multi-scale feature hierarchy with

qualitative relations between features at different scales. Experiments illustrate

the capability of the proposed hierarchy to handle occlusions and semirigid


The second part of the thesis develops a geometric framework for computing

estimates of 3D structure and motion from sparse feature correspondences

in monocular sequences. A tool is presented, called the centered affine trifocal

tensor, for motion estimation from three affine views. Moreover, a factorization

approach is developed which simultaneously handles point and line

correspondences in multiple affine views. Experiments show the influence of

several factors on the accuracy of the structure and motion estimates, including

noise in the feature localization, perspective effects and the number of feature

correspondences. This motion estimation framework is also applied to

feature correspondences obtained from the abovementioned feature tracker.

The last part integrates the functionalities from the first two parts into a

pre-prototype system which explores new principles for human-computer interaction.

The idea is to transfer 3D orientation to a computer using no other

equipment than the operator’s hand.

Place, publisher, year, edition, pages
Stockholm: KTH , 1999. , v, 153 p.
Trita-NA-P, 9907
National Category
Engineering and Technology
URN: urn:nbn:se:kth:diva-2856ISBN: 91-7170-457-4OAI: diva2:8582
Public defence
1999-10-15, 00:00 (English)
QC 20100519Available from: 2000-01-01 Created: 2000-01-01 Last updated: 2010-05-19Bibliographically approved

Open Access in DiVA

fulltext(1256 kB)1421 downloads
File information
File name FULLTEXT01.pdfFile size 1256 kBChecksum SHA-1
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Bretzner, Lars
By organisation
Numerical Analysis and Computer Science, NADA
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 1421 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 451 hits
ReferencesLink to record
Permanent link

Direct link