Falls Sie ein Student sind und nach einer Studien oder
Diplomarbeit ausschau halten, finden Sie
hier
genauere Informationen. Insbesondere kann ich Arbeiten auf den
Gebieten
3D-Rekonstruktion
und
Archäometry
anbieten.
Falls das Ihren Interessen nicht so entgegen kommt, sollten Sie
auch mal einen Blick auf die anderen
bei KOGS angebotenen Themen
werfen.
If you are a student looking for a Diploma-thesis (Diplomarbeit),
please note that I can offer several interesting subjects in
particular in connection with
3D-reconstruction
and
archaeometry
- some are described
here,
but you can always contact me for related topics. You might also
want to have a look at
other subjects currently on offer
at
KOGS.
This is an ongoing research interest (since 1998) more than a real
project. The idea here is to generate a qualitative depth-map from
single images (which is theoretically impossible, but none
the less constantly done by humans looking at pictures). In order
to achive this goal I am utilising a-priori knowledge about the
world (corners are usually right-angle, the floor is usually flat
and horizontal, walls are usually vertical...) and combine it with
some simple reasoning (T-junctions often mean that the part "above"
the T is obscuring the part "below" the "T-bar",...), but of course
also "proper" projective geometry. Unfortunately I have little time
to work on this myself, but it would make a perfect Diplomarbeit.
Archaeometry is the application of methods taken from the natural
sciences - and in my case in particular computer vision - to
archaeological problems. My interest in this area dates back to
1996, when Dr. Peter Werner and Prof. Machule from the TU
Hamburg-Harburg asked Prof. Burkhard for help with the automatic
classification of ancient ceramics, and he in turn asked me, due to
my experience with rotationally symmetric objects4. Unfortunately
this project too is mainly a spare-time activity and relies
on Studien- and Diplomarbeiten.
From 5/2001 till 6/2004 KOGS was a member of CogVis - Cognitive
Vision Systems - a project sponsored by the EU. The aim of CogVis,
as well as a number of similar projects also funded by the EU, was
to "remarry" computer vision on the one hand and artificial
intelligence on the other. Since KOGS is traditionally active in
both fields we were a natural partner. The thumbnail shows part of
an analysis of a table-laying scene, which is the scenario we
concentrated on. Within CogVis I only acted as an advisor on the
computer-vision aspects.
This is the title of my yet to be viva-ed - never mind published -
PhD-thesis. I mostly worked on this from 1995 till about 1999, with
some added effort in 2003/2004. My interest in error-propagation
started when, during the MOVIS-project6, I noticed that the
application of straightforward projective geometry to my particular
task (finding zebra-crossings) didn't work at all as expected - the
measurements I had to work with where much too bad to be of any
use. However, the error I observed was not well modelled by your
usually Gaussians, and this set me thinking. The icon shows an
error-model for the cross-ratio of four lines, an important
projective invariant.
From 1994 till 1997 I worked on the project MOVIS, the "Mobil
Optoelectronic Visual Interpretative System for the blind and
visually impaired", which would put two miniature cameras into
normal glasses, connecting them to a computer and act as some sort
of portable electronic guide dog, but one which can talk and read.
Interestingly both KOGS (my current home) as well as Ti-1 (my former
employer, and the one for which I worked during MOVIS) were part of
MOVIS. Within MOVIS I was mostly concentrating on the recognition
of street-signs; in particular pedestrian crossings but also other
signs of interest, such as bus-stops, signs denoting public phones
(not that many mobiles around in 1994) and such.
In the autumn of 1994 we at the TU Hamburg-Harburg's Ti-1 were asked
to conduct a study to assess the possibilities of automatic visual
inspection of rather small defects on the cardboard printout for
cigarette boxes. These are printed to surprisingly exacting
standards (better then your average art print, I wouldn't be
surprised), and even sub-millimetre defects are unwanted. The study
is of course proprietary, so let me just say that yes, it could be
done, even using 1994 technology and considering the tremendous
speed at which theses things are printed (albeit just barely, and
requiring careful lighting).
From 7/1993 till 1/1994 I was staying with Dr. Zisserman in Oxford,
working on my Diplomarbeit (approx. a MSc). Prof. Burkhard afforded
me that unique opportunity, which combined intense and fruitful
scientific work with a lot of fun! I rarely enjoyed any extended
period of time as much as I enjoyed my stay in Oxford, and would
like to thank all who made it possible. There I worked on the
recognition (and reconstruction) of rotationally symmetric surfaces
from single, projective views.
From 4/1993 till 5/1993 I had some time on my hand in between the
internship and some examinations on the one side and the start of my
Diplomarbeit in Oxford on the other side, so I took up an offer of
the Philips research laboratory to work on software which would map
a recently acquired 3D-map of a human brain onto the actual MRI-scan
of a real brain. Affinely map it, that is, by manually specifying 4
control points - not exactly the state of the art by todays
standards, but in 1993 we were quite happy to get something like
this displayed in reasonable time (3D-acceleration? Hell, you were
lucky if your workstation supported 256 colours!). The main problem
was to intelligently interpolate between individual slices once the
atlas became rotated around the x- or y-axis.
In late 1992 and early 1993 I was fulfilling my internship at Philips GmbH, Forschungsabteilung Technische Systeme Hamburg. Due to my previous experiences with the simulator for the flame-tomography I was assigned the task to write a simulator for an MRI-scanner. The objects in question were very simple head-phantoms like the one to the left, essentially simple, 2D, geometric objects (this was 1992, mind). As its input the program would take a description of the phantom, and as it's output the simulator would generate data which could then directly be fed back into the tomography-software used at Philips; the reconstruction could then be compared with reconstructions of an actual phantom in an actual MRI-scanner.
In late 1991, early 1992 I was working on this project as my "Studienarbeit" (3rd year project, BS-thesis). The goal was to get a tomographic reconstruction of the temperature distribution inside a burning flame (assumed rotationally symmetric) from 4 images taken with narrow-band spectral filters. The trick here is to model the flame both as emitting but also as absorbing light. At that time no hardware was available for the task (albeit ordered), and it was my task to write software which would simulate the burning flame, and also to write software which would do the tomographic reconstruction.
One thing which we learnt from doing the simulations (not that one
couldn't have found out applying some little error-propagation and
common sense) was that we would need a camera with either a
12 Bit linear or 8 Bit logarithmic resolution - both
something not readily available in 1991, which ultimately doomed
this project.
Find out more...
: Error propagation in geometry-based grouping, Albert-Ludwigs-Universität Freiburg, Institut für Informatik, Fakultät für Angewandte Wissenschaften, Doktorarbeit, 2006
[BibTeX]
[Abstract] [Pdf, 11MB]
; ; ; Fachbereich Informatik, Universität Hamburg (Hrsg.): Ancient Ceramics: Computer aided Classification, Mitteilung. FBI-HH-M-338/06, 2006
[BibTeX]
[Abstract] [pdf, 401KB] [ps.gz, 455KB]
: Error-Bounds on Curvature Estimation. In: Scale Space: Springer-Verlag, Berlin, 2003, S. 657--666
[BibTeX]
[pdf, 200KB] [Abstract, 1.0KB]
; Fachbereich Informatik, Universität Hamburg (Hrsg.): Comparison of Different Approaches for the Calculation of Projective Symmetry or the Axis of a SHGC, Bericht. FBI-HH-253/03, 2003
[BibTeX]
[Abstract] [pdf, 1.1MB]
; Fachbereich Informatik, Universität Hamburg (Hrsg.): Error-Bounds on Curvature Estimation, Bericht. FBI-HH-252/03, 2003
[BibTeX]
[Abstract] [pdf, 110KB]
; : Projective Reconstruction of Surfaces of Revolution. In: Michaelis, B. (Hrsg.); Krell, G. (Hrsg.): 25. DAGM-Symposium Mustererkennung. Lecture Notes in Computer Science. Bd. 2781: Springer-Verlag, Berlin, 2003. - ISBN 3-540-40861-4, S. 265--272
[BibTeX]
[pdf, 660KB] [Abstract, 1.0KB]
: Grouping based on Projective Geometry Constraints and Uncertainty. In: Proceedings of the Sixth International Conference on Computer Vision: Narosa Publishing House, New Delhi, 1998. - ISBN 81-7319-221-9, S. 739--746
[BibTeX]
[ps.gz, 1.3MB] [Abstract, 1.0KB]
; ; ; ; Albert-Ludwigs-Universität, Freiburg, Institut für Informatik (Hrsg.): MOVIS: Über die Entwicklung eines ersten Prototypen einer Blindenbrille, Interner Bericht. 3/98, 1998
[BibTeX]
[ps.gz]
; Technische Informatik I, TU-HH (Hrsg.): Grouping based on Projective Geometry Constraints and Uncertainty, Interner Bericht. 1/97, 1997
[BibTeX]
[ps.gz, 1.9MB] [Abstract, 1.0KB]
; ; ; ; ; ; ; : An Experimental Comparison of Appearance and Geometric Model Based Recognition, 1996
[BibTeX]
; ; ; ; ; ; ; : An Experimental Comparison of Appearance and Geometric Model Based Recognition. In: Proc. Object Representation in Computer Vision II. LNCS 1144: Springer-Verlag, 1996, S. 247--269
[BibTeX]
[Postscript, 1.6MB] [Abstract, 1.5KB]
; ; ; ; ; ; : Class-Based Grouping in Perspective Images. In: Proceedings of the Fifth International Conference on Computer Vision, 1995, S. 183--188
[BibTeX]
[ps.gz, 735KB] [Abstract, 1.8KB]
; : Advanced Quality Inspection through Physics-Based Vision. In: Proc. of the the International Symposium Machine Vision in the Industrial Practice, 1995
[BibTeX]
[Postscript, 1.2MB] [Abstract, 1.5KB]
; ; : Viewpoint-Invariant Representation of Generalized Cylinders Using the Symmetry Set. In: British Machine Vision Conference, 1994
[BibTeX]
; ; ; ; ; ; ; ; : MORSE: A 3D Object Recognition System based on Geometric Invariants. In: Kaufmann, Morgan (Hrsg.): Image Understanding Workshop, 1994, S. II:1393--1402
[BibTeX]
[ps.gz, 216KB] [Abstract, 0.5KB]
: Transfer and Invariants of Surfaces of Revolution, Technische Universität Hamburg-Harburg, Diplomarbeit, 1994
[BibTeX]
[ps.gz, 1.6MB] [pdf, 1.4MB]
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