Mathias   ORTNER
Page en francais
Professional address
INRIA - Sophia Antipolis
BP 93, 2004 Route des Lucioles
06902 Sophia Antipolis Cedex

Tel: +33 / 4 92 38 75 68
Fax: +33 / 4 92 38 76 43


Who I am ?
See my cv
I am finishing my Ph. D. Thesis. I am working within the Ariana project. My work uses some probabilistic tools like spatial point processes to infer from the altimetry of an urban scene its 3d simplified map.

Under this introduction, you will find below what my Ph. D. is precisly about, a presentation that explains my research work and a list of publications and papers I have recently written.

Ph. D. Subject

Building detection on Digital Elevation Models

Digital Elevation Models given by automatic processing of aerial images exhibit some geometrical artefacts (misplaced walls, presence of trees or cars etc. .). The objective of this work is to build a simple geometrical model of buildings and to extract objects from the DEM which are close with respect to this geometrical model. The goal of this work is to improve the scene reconstruction.

We choose to use stochastic geometry as our tool. We use marked point processes. These mathematical objects are quite new in image processing and give us the freedom on the kind of object we want to introduce in the model. Moreover, these marked point processes fit in well with our goals as they allow us to add interactions between objects such as alignement constraints on buildings. To optimize the model we use a Reversible Jump Markov Chain Monte Carlo algorithm.
Evaluation of this model technique will be carried out using real data given by IGN (French Mapping Institute).


  • Josiane Zerubia
    Director or research, INRIA, (tel.: 04 92 38 78 65, email :
  • Xavier Descombes
    Xavier Descombes, INRIA, (tel.: 04 92 38 76 63, email :

This link to the demo will allow you to discover pages presenting my work. This pages use the results I obtained after my first year of Ph. D.

October 2001 Invited Seminar VISTA Project, Irisa Rennes
October 2001 Invited Seminar Celar, DGA (French Defense Agency Lab) Rennes
December 2001 Invited Seminar CWI Amsterdam
February 2002Seminar INRIA Sophia Antipolis
August 2002Invited SeminarBRGM (French Geological Survey), Orleans
September 2002Invited SeminarAlcatel Space Cannes
January 2003Oral CommunicationJacques-Louis Lions Lab (Applied Mathematics), University of Paris VI
May 2003 SeminarINRIA Sophia Antipolis
May 2003Invited SeminarCTA, DGA (French Defense Agency Lab), Arcueil Paris
November 2003 Oral CommunicationCNES (French Space Agency)/ DLR (German Space Agency), at DLR, Oberpfaffenoffen
December 2003Invited SeminarDLR (German Space Agency), Oberpfaffenoffen
Jan. 2004Seminar MATIS Lab, IGN (French Mapping Institute) Paris

Youg Authors Award for the following paper :

A Discontinuity detector for building extraction from Digital Elevation Models by stochastic geometry. M. Ortner, X. Descombes and J. Zerubia, In Proc. of EUSIPCO'04. Vienna, September 2004.

Master thesis

Research Reports :

Invited communications :

  • Marked point processes in image analysis: from context to geometry. X. Descombes, F. Kruggel, C. Lacoste, M. Ortner, G. Perrin and J. Zerubia. In "Spatial Point Process Modelling and its Applications", Castellon (Spain), April 2004.
  • A Reversible Jump MCMC sampler for building detection in image processing. M. Ortner, X. Descombes and J. Zerubia. In " Monte Carlo methods and quasi-Monte Carlo methods ", Special Session "In Image Processing.". Juan Les Pins (France), June 2004.

Proceedings of French-speaking conferences

French Journal with review :

  • Extraction automatique de caricatures de batiments sur des Modèles Numériques d'Elévation. M. Ortner, X. Descombes, and J. Zerubia. In "Revue de la S.F.P.T." (Journal of the French Society of Remote Sensing and Photogrammetry) n 173/174 p.83-92, 1/2, 2004.

Proceedings of International Conferences :

International Journal Paper :

  • Building outline extraction from Digital Elevation Models using marked point processes. M. Ortner, X. Descombes and J. Zerubia, submitted to IJCV in november 2003 (under revision).

Chapter of books :

  • A Reversible Jump MCMC sampler for building detection in image processing. M. Ortner, X. Descombes and J. Zerubia. Submitted for a Springer Verlag publication in the proceedings of the conference MC2QMC : "Monte Carlo and Quasi Monte Carlo Methods in scientific computing", Juan Les Pins (France), June 2004. Editors will be Harald Niederreiter and Denis Talay.