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Publications sur Contour actif
Résultat de la recherche dans la liste des publications :
5 Articles |
1 - A Marked Point Process Model Including Strong Prior Shape Information Applied to Multiple Object Extraction From Images.
M. S. Kulikova et I. H. Jermyn et X. Descombes et E. Zhizhina et J. Zerubia. International Journal of Computer Vision and Image Processing, 1(2): pages 1-12, 2011.
Mots-clés : Contour actif, Processus ponctuels marques, multiple birth-and-death dynamics, multiple object extraction, Shape prior.
@ARTICLE{kulikova_ijcvip2010,
|
| author |
= |
{Kulikova, M. S. and Jermyn, I. H. and Descombes, X. and Zhizhina, E. and Zerubia, J.}, |
| title |
= |
{A Marked Point Process Model Including Strong Prior Shape Information Applied to Multiple Object Extraction From Images}, |
| year |
= |
{2011}, |
| journal |
= |
{International Journal of Computer Vision and Image Processing}, |
| volume |
= |
{1}, |
| number |
= |
{2}, |
| pages |
= |
{1-12}, |
| url |
= |
{http://hal.archives-ouvertes.fr/hal-00804118}, |
| keyword |
= |
{Contour actif, Processus ponctuels marques, multiple birth-and-death dynamics, multiple object extraction, Shape prior} |
| } |
Abstract :
Object extraction from images is one of the most important tasks in remote sensing image analysis. For accurate extraction from very high resolution (VHR) images, object geometry needs to be taken into account. A method for incorporating strong yet flexible prior shape information into a marked point process model for the extraction of multiple objects of complex shape is presented. To control the computational complexity, the objects considered are defined using the image data and the prior shape information. To estimate the optimal configuration of objects, the process is sampled using a Markov chain based on a stochastic birth-and-death process on the space of multiple objects. The authors present several experimental results on the extraction of tree crowns from VHR aerial images. |
|
2 - Extended Phase Field Higher-Order Active Contour Models for Networks.
T. Peng et I. H. Jermyn et V. Prinet et J. Zerubia. International Journal of Computer Vision, 88(1): pages 111-128, mai 2010.
Mots-clés : Contour actif, Champ de Phase, Shape prior, Parameter analysis, remote sensing, Road network extraction.
@ARTICLE{Peng09,
|
| author |
= |
{Peng, T. and Jermyn, I. H. and Prinet, V. and Zerubia, J.}, |
| title |
= |
{ Extended Phase Field Higher-Order Active Contour Models for Networks}, |
| year |
= |
{2010}, |
| month |
= |
{mai}, |
| journal |
= |
{International Journal of Computer Vision}, |
| volume |
= |
{88}, |
| number |
= |
{1}, |
| pages |
= |
{ 111-128}, |
| url |
= |
{http://www.springerlink.com/content/d3641g2227316w58/}, |
| keyword |
= |
{Contour actif, Champ de Phase, Shape prior, Parameter analysis, remote sensing, Road network extraction} |
| } |
Abstract :
This paper addresses the segmentation from an image of entities that have the form of a ‘network’, i.e. the region in the image corresponding to the entity is composed of branches joining together at junctions, e.g. road or vascular networks. We present new phase field higher-order active contour (HOAC) prior models for network regions, and apply them to the segmentation of road networks from very high resolution satellite images. This is a hard problem for two reasons. First, the images are complex, with much ‘noise’ in the road region due to cars, road markings, etc., while the background is very varied, containing many features that are locally similar to roads. Second, network regions are complex to model, because they may have arbitrary topology. In particular, we address a limitation of a previous model in which network branch width was constrained to be similar to maximum network branch radius of curvature, thereby providing a poor model of networks with straight narrow branches or highly curved, wide branches. We solve this problem by introducing first an additional nonlinear nonlocal HOAC term, and then an additional linear nonlocal HOAC term to improve the computational speed. Both terms allow separate control of branch width and branch curvature, and furnish better prolongation for the same width, but the linear term has several advantages: it is more efficient, and it is able to model multiple widths simultaneously. To cope with the difficulty of parameter selection for these models, we perform a stability analysis of a long bar with a given width, and hence show how to choose the parameters of the energy functions. After adding a likelihood energy, we use both models to extract the road network quasi-automatically from pieces of a QuickBird image, and compare the results to other models in the literature. The state-of-the-art results obtained demonstrate the superiority of our new models, the importance of strong prior knowledge in general, and of the new terms in particular. |
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3 - A higher-order active contour model of a ‘gas of circles' and its application to tree crown extraction.
P. Horvath et I. H. Jermyn et Z. Kato et J. Zerubia. Pattern Recognition, 42(5): pages 699-709, mai 2009.
Mots-clés : Forme, Ordre superieur, Contour actif, Gaz de cercles, Extraction de Houppiers, Bayesian.
@ARTICLE{Horvath09,
|
| author |
= |
{Horvath, P. and Jermyn, I. H. and Kato, Z. and Zerubia, J.}, |
| title |
= |
{A higher-order active contour model of a ‘gas of circles' and its application to tree crown extraction}, |
| year |
= |
{2009}, |
| month |
= |
{mai}, |
| journal |
= |
{Pattern Recognition}, |
| volume |
= |
{42}, |
| number |
= |
{5}, |
| pages |
= |
{699-709}, |
| url |
= |
{http://dx.doi.org/10.1016/j.patcog.2008.09.008}, |
| pdf |
= |
{http://www-sop.inria.fr/members/Ian.Jermyn/publications/Horvathetal09.pdf}, |
| keyword |
= |
{Forme, Ordre superieur, Contour actif, Gaz de cercles, Extraction de Houppiers, Bayesian} |
| } |
Abstract :
We present a model of a ‘gas of circles’: regions in the image domain composed of a unknown
number of circles of approximately the same radius. The model has applications
to medical, biological, nanotechnological, and remote sensing imaging. The model is constructed
using higher-order active contours (HOACs) in order to include non-trivial prior
knowledge about region shape without constraining topology. The main theoretical contribution
is an analysis of the local minima of the HOAC energy that allows us to guarantee
stable circles, fix one of the model parameters, and constrain the rest. We apply the model
to tree crown extraction from aerial images of plantations. Numerical experiments both
confirm the theoretical analysis and show the empirical importance of the prior shape information. |
|
4 - Higher-Order Active Contour Energies for Gap Closure.
M. Rochery et I. H. Jermyn et J. Zerubia. Journal of Mathematical Imaging and Vision, 29(1): pages 1-20, septembre 2007.
Mots-clés : Gap closure, Ordre superieur, Contour actif, Forme, A priori, Reseaux routiers.
@ARTICLE{Rochery07,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Higher-Order Active Contour Energies for Gap Closure}, |
| year |
= |
{2007}, |
| month |
= |
{septembre}, |
| journal |
= |
{Journal of Mathematical Imaging and Vision}, |
| volume |
= |
{29}, |
| number |
= |
{1}, |
| pages |
= |
{1-20}, |
| url |
= |
{http://dx.doi.org/10.1007/s10851-007-0021-x}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/2007_Rochery07.pdf}, |
| keyword |
= |
{Gap closure, Ordre superieur, Contour actif, Forme, A priori, Reseaux routiers} |
| } |
Abstract :
One of the main difficulties in extracting line networks from images, and in particular road networks from remote sensing images, is the existence of interruptions in the data caused, for example, by occlusions. These can lead to gaps in the extracted network that do not correspond to gaps in the real network. In this paper, we describe a higher-order active contour energy that in addition to favouring network-like regions, includes a prior term penalizing networks containing ‘nearby opposing extremities’, thereby making gaps in the extracted network less likely. The new energy term causes such extremities to attract one another during gradient descent. They thus move towards one another and join, closing the gap. To minimize the energy, we develop specific techniques to handle the high-order derivatives that appear in the gradient descent equation. We present the results of automatic extraction of networks from real remote-sensing images, showing the ability of the model to overcome interruptions. |
|
5 - Higher Order Active Contours.
M. Rochery et I. H. Jermyn et J. Zerubia. International Journal of Computer Vision, 69(1): pages 27--42, août 2006.
Mots-clés : Contour actif, Forme, Ordre superieur, A priori, Reseaux routiers.
@ARTICLE{mr_ijcv_06,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Higher Order Active Contours}, |
| year |
= |
{2006}, |
| month |
= |
{août}, |
| journal |
= |
{International Journal of Computer Vision}, |
| volume |
= |
{69}, |
| number |
= |
{1}, |
| pages |
= |
{27--42}, |
| url |
= |
{http://dx.doi.org/10.1007/s11263-006-6851-y}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/2006_mr_ijcv_06.pdf}, |
| keyword |
= |
{Contour actif, Forme, Ordre superieur, A priori, Reseaux routiers} |
| } |
Abstract :
We introduce a new class of active contour models that
hold great promise for region and shape modelling, and
we apply a special case of these models to the
extraction of road networks from satellite and aerial
imagery. The new models are arbitrary polynomial
functionals on the space of boundaries, and thus
greatly generalize the linear functionals used in
classical contour energies. While classical energies
are expressed as single integrals over the contour,
the new energies incorporate multiple integrals, and
thus describe long-range interactions between
different sets of contour points. As prior terms, they
describe families of contours that share complex
geometric properties, without making reference to any
particular shape, and they require no pose estimation.
As likelihood terms, they can describe multi-point
interactions between the contour and the data. To
optimize the energies, we use a level set approach.
The forces derived from the new energies are non-local
however, thus necessitating an extension of standard
level set methods. Networks are a shape family of
great importance in a number of applications,
including remote sensing imagery. To model them, we
make a particular choice of prior quadratic energy
that describes reticulated structures, and augment it
with a likelihood term that couples the data at pairs
of contour points to their joint geometry. Promising
experimental results are shown on real images. |
|
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2 Thèses de Doctorat et Habilitations |
1 - Contours actifs d'ordre supérieur et leur application à la détection de linéiques dans des images de télédétection.
M. Rochery. Thèse de Doctorat, Universite de Nice Sophia Antipolis, Sophia Antipolis, septembre 2005.
Mots-clés : Contour actif, Ordre superieur, Champ de Phase, Reseaux lineiques, Reseaux routiers.
@PHDTHESIS{rochery_these,
|
| author |
= |
{Rochery, M.}, |
| title |
= |
{Contours actifs d'ordre supérieur et leur application à la détection de linéiques dans des images de télédétection}, |
| year |
= |
{2005}, |
| month |
= |
{septembre}, |
| school |
= |
{Universite de Nice Sophia Antipolis}, |
| address |
= |
{Sophia Antipolis}, |
| pdf |
= |
{http://hal.inria.fr/docs/00/04/86/28/PDF/tel-00010631.pdf}, |
| keyword |
= |
{Contour actif, Ordre superieur, Champ de Phase, Reseaux lineiques, Reseaux routiers} |
| } |
|
2 - Contribution à la classification d'images satellitaires par approche variationnelle et équations aux dérivées partielles.
C. Samson. Thèse de Doctorat, Universite de Nice Sophia Antipolis, septembre 2000.
Mots-clés : Classification, Restauration, Courbes de niveaux, Contour actif.
@PHDTHESIS{cs,
|
| author |
= |
{Samson, C.}, |
| title |
= |
{Contribution à la classification d'images satellitaires par approche variationnelle et équations aux dérivées partielles}, |
| year |
= |
{2000}, |
| month |
= |
{septembre}, |
| school |
= |
{Universite de Nice Sophia Antipolis}, |
| url |
= |
{https://tel.archives-ouvertes.fr/tel-00319709}, |
| pdf |
= |
{http://tel.archives-ouvertes.fr/docs/00/31/97/09/PDF/SAMSONthesis.pdf}, |
| keyword |
= |
{Classification, Restauration, Courbes de niveaux, Contour actif} |
| } |
Résumé :
Ce travail est consacré au développement ainsi qu'à l'implantation de deux modèles variationnels pour la classification d'images. La classification d'images, consistant à attribuer une étiquette à chaque pixel d'une image, concerne de nombreuses applications à partir du moment où cette opération intervient très souvent à la base des chaînes de traitement et d'interprétation d'images. De nombreux modèles de classification ont déjà été développés dans un cadre stochastique ou à travers des approches structurales, mais rarement dans un contexte variationnel qui a déjà montré son efficacité dans divers domaines tels que la reconstruction ou la restauration d'images. Le premier modèle que nous proposons repose sur la minimisation d'une famille de critères dont la suite de solutions converge vers une partition des données composée de classes homogènes séparées par des contours réguliers. Cette approche entre dans le cadre des problèmes à discontinuité libre (it free discontinuity problems) et fait appel à des notions de convergence variationnelle telle que la théorie de la Gamma-convergence. La famille de fonctionnelles que nous proposons de minimiser contient un terme de régularisation, ainsi qu'un terme de classification. Lors de la convergence de cette suite de critères, le modèle change progressivement de comportement en commençant par restaurer l'image avant d'entamer le processus d'étiquetage des pixels. Parallèlement à cette approche, nous avons développé un second modèle de classification mettant en jeu un ensemble de régions et contours actifs. Nous utilisons une approche par ensembles de niveaux pour définir le critère à minimiser, cette approche ayant déjà suscité de nombreux travaux dans le cadre de la segmentation d'images. Chaque classe, et son ensemble de régions et contours associé, est défini à travers une fonction d'ensemble de niveaux. Le critère contient des termes reliés à l'information sur les régions ainsi qu'à l'information sur les contours. Nous aboutissons à la résolution d'un système d'équations aux dérivées partielles couplées et plongées dans un schéma dynamique. L'évolution de chaque région est guidée par un jeu de forces permettant d'obtenir une partition de l'image composée de classes homogènes et dont les frontières sont lisses. Nous avons mené des expériences sur de nombreuses données synthétiques ainsi que sur des images satellitaires SPOT. Nous avons également étendu ces deux modèles au cas de données multispectrales et obtenu des résultats sur des données SPOT XS que nous avons comparé à ceux obtenus par différents modèles. |
Abstract :
This work is devoted to the development and the implementation of variational models for image classification.\ Image classification, which consists in assiging a label to each pixel of a given image, concerns many applications since it is often the basic processing for many image interpretation systems. Many models have been developed within a stochastic framework or using structural approaches, but rarely within a variational framework whose efficiency has largely been proved for a wide variety of problems such as image reconstruction or restoration. The first model we propose herein is based on the minimization of a criterion family whose set of solutions in converging to a partition of the data set composed of homogeneous regions with regularized boundaries. This approach takes place within the context of free boundary problems and we use the Gamma-convergence theory for the theoretical study. The set of functionals we minimize contains a regularization term and a classification one. As the set of functionals is converging, the behavior of the model is progressively changing: the restoration process is vanishing while the labeling one is rising. The second model we propose is based on a set of active regions and contours. We use a level set formulation to define the criterion we want to minimize, this formulation allows a change of topology of the evolving sets. Each class and its associated set of regions and boundaries is defined thanks to a level set function. From the Euler equations, we solve a system of coupled partial differential equations through a dynamical scheme. The evolution of each region is governed by forces constraining the partition to be composed of homogeneous classes with smooth boundaries.\ We have conducted many experiments on both synthetic and real images. We have extended these models to the multispectral case for which the data are a set of images, and we show some results and comparisons on SPOT XS images. |
|
haut de la page
10 Articles de conférence |
1 - Extraction of arbitrarily shaped objects using stochastic multiple birth-and-death dynamics and active contours.
M. S. Kulikova et I. H. Jermyn et X. Descombes et E. Zhizhina et J. Zerubia. Dans Proc. IS&T/SPIE Electronic Imaging, San Jose, USA, janvier 2010.
Mots-clés : Extraction d'objets, Processus ponctuels marques, Shape prior, Contour actif, birth-and-death dynamics.
Copyright : Copyright 2010 by SPIE and IS&T. This paper was published in the proceedings of IS&T/SPIE Electronic Imaging 2010 Conference in San Jose, USA, and is made available as an electronic reprint with permission of SPIE and IS&T. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
@INPROCEEDINGS{Kulikova10a,
|
| author |
= |
{Kulikova, M. S. and Jermyn, I. H. and Descombes, X. and Zhizhina, E. and Zerubia, J.}, |
| title |
= |
{Extraction of arbitrarily shaped objects using stochastic multiple birth-and-death dynamics and active contours}, |
| year |
= |
{2010}, |
| month |
= |
{janvier}, |
| booktitle |
= |
{Proc. IS&T/SPIE Electronic Imaging}, |
| address |
= |
{San Jose, USA}, |
| pdf |
= |
{http://hal.archives-ouvertes.fr/docs/00/46/54/72/PDF/Kulikova_SPIE2010.pdf}, |
| keyword |
= |
{Extraction d'objets, Processus ponctuels marques, Shape prior, Contour actif, birth-and-death dynamics} |
| } |
Abstract :
We extend the marked point process models that have been used for object extraction from images to arbitrarily shaped objects, without greatly increasing the computational complexity of sampling and estimation. From an alternative point of view, the approach can be viewed as an extension of the active contour methodology to an a priori unknown number of
objects. Sampling and estimation are based on a stochastic birth-and-death process defined on the configuration space of an arbitrary number of objects, where the objects are defined by the image data and prior information. The performance of the approach is demonstrated via experimental results on synthetic and real data. |
|
2 - A marked point process model with strong prior shape information for extraction of multiple, arbitrarily-shaped objects.
M. S. Kulikova et I. H. Jermyn et X. Descombes et E. Zhizhina et J. Zerubia. Dans Proc. IEEE SITIS, Publ. IEEE Computer Society, Marrakech, Maroc, décembre 2009.
Mots-clés : Extraction d'objets, Processus ponctuels marques, Shape prior, Contour actif, multiple birth-and-death dynamics.
@INPROCEEDINGS{Kulikova09a,
|
| author |
= |
{Kulikova, M. S. and Jermyn, I. H. and Descombes, X. and Zhizhina, E. and Zerubia, J.}, |
| title |
= |
{A marked point process model with strong prior shape information for extraction of multiple, arbitrarily-shaped objects}, |
| year |
= |
{2009}, |
| month |
= |
{décembre}, |
| booktitle |
= |
{Proc. IEEE SITIS}, |
| publisher |
= |
{IEEE Computer Society}, |
| address |
= |
{Marrakech, Maroc}, |
| pdf |
= |
{http://hal.inria.fr/docs/00/43/63/20/PDF/PID1054029.pdf}, |
| keyword |
= |
{Extraction d'objets, Processus ponctuels marques, Shape prior, Contour actif, multiple birth-and-death dynamics} |
| } |
Abstract :
We define a method for incorporating strong prior shape information into a recently extended Markov point process model for the extraction of arbitrarily-shaped objects from images. To estimate the optimal configuration of objects, the process is sampled using a Markov chain based on a stochastic birth-and-death process defined in a space of multiple
objects. The single objects considered are defined by both the image data
and the prior information in a way that controls the computational
complexity of the estimation problem. The method is tested via experiments
on a very high resolution aerial image of a scene composed of tree crowns. |
|
3 - A Phase Field Model Incorporating Generic and Specific Prior Knowledge Applied to Road Network Extraction from VHR Satellite Images.
T. Peng et I. H. Jermyn et V. Prinet et J. Zerubia et B. Hu. Dans Proc. British Machine Vision Conference (BMVC), Warwick, UK, septembre 2007.
Mots-clés : Reseaux routiers, Very high resolution, Ordre superieur, Contour actif, Forme, A priori.
@INPROCEEDINGS{Peng07a,
|
| author |
= |
{Peng, T. and Jermyn, I. H. and Prinet, V. and Zerubia, J. and Hu, B.}, |
| title |
= |
{A Phase Field Model Incorporating Generic and Specific Prior Knowledge Applied to Road Network Extraction from VHR Satellite Images}, |
| year |
= |
{2007}, |
| month |
= |
{septembre}, |
| booktitle |
= |
{Proc. British Machine Vision Conference (BMVC)}, |
| address |
= |
{Warwick, UK}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/2007_Peng07a.pdf}, |
| keyword |
= |
{Reseaux routiers, Very high resolution, Ordre superieur, Contour actif, Forme, A priori} |
| } |
Abstract :
We address the problem of updating road maps in dense urban areas by extracting the main road network from a very high resolution (VHR) satellite image. Our model of the region occupied by the road network in the image is innovative. It incorporates three different types of prior geometric knowledge: generic boundary smoothness constraints, equivalent to a standard active contour prior; knowledge of the geometric properties of road networks (i.e. that they occupy regions composed of long, low-curvature segments joined at junctions), equivalent to a higher-order active contour prior; and knowledge of the road network at an earlier date derived from GIS data, similar to other ‘shape priors’ in the literature. In addition, we represent the road network region as a ‘phase field’, which offers a number of important advantages over other region modelling frameworks. All three types of prior knowledge prove important for overcoming the complexity of geometric ‘noise’ in VHR images. Promising results and a comparison with several other techniques demonstrate the effectiveness of our approach. |
|
4 - Urban road extraction from VHR images using a multiscale image model and a phase field model of network geometry.
T. Peng et I. H. Jermyn et V. Prinet et J. Zerubia. Dans Proc. Urban, Paris, France, avril 2007.
Mots-clés : Reseaux routiers, Very high resolution, Multiscale, Ordre superieur, Contour actif, Forme.
@INPROCEEDINGS{Peng07_urban,
|
| author |
= |
{Peng, T. and Jermyn, I. H. and Prinet, V. and Zerubia, J.}, |
| title |
= |
{Urban road extraction from VHR images using a multiscale image model and a phase field model of network geometry}, |
| year |
= |
{2007}, |
| month |
= |
{avril}, |
| booktitle |
= |
{Proc. Urban}, |
| address |
= |
{Paris, France}, |
| pdf |
= |
{http://www-sop.inria.fr/members/Ian.Jermyn/publications/Peng07urban.pdf}, |
| keyword |
= |
{Reseaux routiers, Very high resolution, Multiscale, Ordre superieur, Contour actif, Forme} |
| } |
Abstract :
This paper addresses the problem of automatically
extracting the main road network in a dense urban area from
a very high resolution optical satellite image using a variational
approach. The model energy has two parts: a phase field higherorder
active contour energy that describes our prior knowledge
of road network geometry, i.e. that it is composed of elongated
structures with roughly parallel borders that meet at junctions;
and a multi-scale statistical image model describing the image
we expect to see given a road network. By minimizing the model
energy, an estimate of the road network is obtained. Promising
results on 0.6m QuickBird Panchromatic images are presented,
and future improvements to the models are outlined. |
|
5 - An improved 'gas of circles' higher-order active contour model and its application to tree crown extraction.
P. Horvath et I. H. Jermyn et Z. Kato et J. Zerubia. Dans Proc. Indian Conference on Computer Vision, Graphics, and Image Processing (ICVGIP), Madurai, India, décembre 2006.
Mots-clés : Extraction de Houppiers, Aerial images, Ordre superieur, Contour actif, Gaz de cercles, Forme.
@INPROCEEDINGS{Horvath06_icvgip,
|
| author |
= |
{Horvath, P. and Jermyn, I. H. and Kato, Z. and Zerubia, J.}, |
| title |
= |
{An improved 'gas of circles' higher-order active contour model and its application to tree crown extraction}, |
| year |
= |
{2006}, |
| month |
= |
{décembre}, |
| booktitle |
= |
{Proc. Indian Conference on Computer Vision, Graphics, and Image Processing (ICVGIP)}, |
| address |
= |
{Madurai, India}, |
| url |
= |
{http://dx.doi.org/10.1007/11949619_14}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/2006_Horvath06_icvgip.pdf}, |
| keyword |
= |
{Extraction de Houppiers, Aerial images, Ordre superieur, Contour actif, Gaz de cercles, Forme} |
| } |
Abstract :
A central task in image processing is to find the
region in the image corresponding to an entity. In a
number of problems, the region takes the form of a
collection of circles, eg tree crowns in remote
sensing imagery; cells in biological and medical
imagery. In~citeHorvath06b, a model of such regions,
the `gas of circles' model, was developed based on
higher-order active contours, a recently developed
framework for the inclusion of prior knowledge in
active contour energies. However, the model suffers
from a defect. In~citeHorvath06b, the model
parameters were adjusted so that the circles were local
energy minima. Gradient descent can become stuck in
these minima, producing phantom circles even with no
supporting data. We solve this problem by calculating,
via a Taylor expansion of the energy, parameter values
that make circles into energy inflection points rather
than minima. As a bonus, the constraint halves the
number of model parameters, and severely constrains one
of the two that remain, a major advantage for an
energy-based model. We use the model for tree crown
extraction from aerial images. Experiments show that
despite the lack of parametric freedom, the new model
performs better than the old, and much better than a
classical active contour. |
|
6 - A Higher-Order Active Contour Model for Tree Detection.
P. Horvath et I. H. Jermyn et Z. Kato et J. Zerubia. Dans Proc. International Conference on Pattern Recognition (ICPR), Hong Kong, août 2006.
Mots-clés : Contour actif, Gaz de cercles, Ordre superieur, Forme, A priori, Extraction de Houppiers.
@INPROCEEDINGS{horvath_icpr06,
|
| author |
= |
{Horvath, P. and Jermyn, I. H. and Kato, Z. and Zerubia, J.}, |
| title |
= |
{A Higher-Order Active Contour Model for Tree Detection}, |
| year |
= |
{2006}, |
| month |
= |
{août}, |
| booktitle |
= |
{Proc. International Conference on Pattern Recognition (ICPR)}, |
| address |
= |
{Hong Kong}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/2006_horvath_icpr06.pdf}, |
| keyword |
= |
{Contour actif, Gaz de cercles, Ordre superieur, Forme, A priori, Extraction de Houppiers} |
| } |
Abstract :
We present a model of a ‘gas of circles’, the ensemble
of regions in the image domain consisting of an
unknown number of circles with approximately fixed
radius and short range repulsive interactions, and
apply it to the extraction of tree crowns from aerial
images. The method uses the re- cently introduced
‘higher order active contours’ (HOACs), which
incorporate long-range interactions between contour
points, and thereby include prior geometric
information without using a template shape. This makes
them ideal when looking for multiple instances of an
entity in an image. We study an existing HOAC model
for networks, and show via a stability calculation
that circles stable to perturbations are possible
for constrained parameter sets. Combining this prior
energy with a data term, we show results on aerial
imagery that demonstrate the effectiveness of the
method and the need for prior geometric knowledge. The
model has many other potential applications. |
|
7 - Phase field models and higher-order active contours.
M. Rochery et I. H. Jermyn et J. Zerubia. Dans Proc. IEEE International Conference on Computer Vision (ICCV), Beijing, China, octobre 2005.
Mots-clés : Contour actif, Ordre superieur, Forme, Reseaux lineiques, Reseaux routiers, Champ de Phase.
@INPROCEEDINGS{rochery_iccv05,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Phase field models and higher-order active contours}, |
| year |
= |
{2005}, |
| month |
= |
{octobre}, |
| booktitle |
= |
{Proc. IEEE International Conference on Computer Vision (ICCV)}, |
| address |
= |
{Beijing, China}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/rochery_iccv05.pdf}, |
| keyword |
= |
{Contour actif, Ordre superieur, Forme, Reseaux lineiques, Reseaux routiers, Champ de Phase} |
| } |
Abstract :
The representation and modelling of regions is an important topic in computer vision. In this paper, we represent a region via a level set of a `phase field' function. The function is not constrained, eg to be a distance function; nevertheless, phase field energies equivalent to classical active contour energies can be defined. They represent an advantageous alternative to other methods: a linear representation space; ease of implementation (a PDE with no reinitialization); neutral initialization; greater topological freedom. We extend the basic phase field model with terms that reproduce `higher-order active contour' energies, a powerful way of including prior geometric knowledge in the active contour framework via nonlocal interactions between contour points. In addition to the above advantages, the phase field greatly simplifies the analysis and implementation of the higher-order terms. We define a phase field model that favours regions composed of thin arms meeting at junctions, combine this with image terms, and apply the model to the extraction of line networks from remote sensing images. |
|
8 - New Higher-order Active Contour Energies for Network Extraction.
M. Rochery et I. H. Jermyn et J. Zerubia. Dans Proc. IEEE International Conference on Image Processing (ICIP), Genoa, Italy, septembre 2005.
Mots-clés : Gap closure, Forme, A priori, Ordre superieur, Contour actif.
@INPROCEEDINGS{rochery_icip05,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{New Higher-order Active Contour Energies for Network Extraction}, |
| year |
= |
{2005}, |
| month |
= |
{septembre}, |
| booktitle |
= |
{Proc. IEEE International Conference on Image Processing (ICIP)}, |
| address |
= |
{Genoa, Italy}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/rochery_icip05.pdf}, |
| keyword |
= |
{Gap closure, Forme, A priori, Ordre superieur, Contour actif} |
| } |
Abstract :
Using the framework of higher-order active contours, we present a new quadratic em continuation energy for the extraction of line networks (e.g. road, hydrographic, vascular) in the presence of occlusions. Occlusions create gaps in the data that frequently translate to gaps in the extracted network. The new energy penalizes earby opposing extremities of the network, and thus favours the closure of the gaps created by occlusions. Nearby opposing extremities are identified using a
sophisticated interaction between pairs of points on the contour. This new model allows the extraction of fully connected networks, even though occlusions violate common assumptions about the homogeneity of the
interior, and high contrast with the exterior, of the network. We present experimental results on real aerial images that demonstrate the effectiveness of the new model for network extraction tasks. |
|
9 - Gap closure in (road) networks using higher-order active contours.
M. Rochery et I. H. Jermyn et J. Zerubia. Dans Proc. IEEE International Conference on Image Processing (ICIP), Singapore, octobre 2004.
Mots-clés : Contour actif, Gap closure, Ordre superieur, Forme, Reseaux routiers.
@INPROCEEDINGS{Rochery04,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Gap closure in (road) networks using higher-order active contours}, |
| year |
= |
{2004}, |
| month |
= |
{octobre}, |
| booktitle |
= |
{Proc. IEEE International Conference on Image Processing (ICIP)}, |
| address |
= |
{Singapore}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/rochery_icip04.pdf}, |
| keyword |
= |
{Contour actif, Gap closure, Ordre superieur, Forme, Reseaux routiers} |
| } |
Abstract :
We present a new model for the extraction of networks from images in the presence of occlusions. Such occlusions cause gaps in the extracted network that need to be closed. Using higher-order active contours, which allow the incorporation of sophisticated geometric information, we introduce a new, non-local, `gap closure' force that causes pairs of network extremities that are close together to extend towards one another and join, thus closing the gap
between them. We demonstrate the benefits of the model using the problem of road network extraction, presenting results on aerial images. |
|
10 - Higher Order Active Contours and their Application to the Detection of Line Networks in Satellite Imagery.
M. Rochery et I. H. Jermyn et J. Zerubia. Dans Proc. IEEE Workshop Variational, Geometric and Level Set Methods in Computer Vision, at ICCV, Nice, France, octobre 2003.
Mots-clés : Ordre superieur, Contour actif, Forme, Reseaux routiers, Segmentation, A priori.
@INPROCEEDINGS{Rochery03a,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Higher Order Active Contours and their Application to the Detection of Line Networks in Satellite Imagery}, |
| year |
= |
{2003}, |
| month |
= |
{octobre}, |
| booktitle |
= |
{Proc. IEEE Workshop Variational, Geometric and Level Set Methods in Computer Vision}, |
| address |
= |
{at ICCV, Nice, France}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/rochery_vlsm03.pdf}, |
| keyword |
= |
{Ordre superieur, Contour actif, Forme, Reseaux routiers, Segmentation, A priori} |
| } |
Abstract :
We present a novel method for the incorporation of shape information
into active contour models, and apply it to the extraction
of line networks (e.g. road, water) from satellite imagery.
The method is based on a new class of contour energies.
These energies are quadratic on the space of one-chains
in the image, as opposed to classical energies, which are linear.
They can be expressed as double integrals on the contour,
and thus incorporate non-trivial interactions between
different contour points. The new energies describe families
of contours that share complex geometric properties, without
making reference to any particular shape. Networks fall
into such a family, and to model them we make a particular
choice of quadratic energy whose minima are reticulated.
To optimize the energies, we use a level set approach. The
forces derived from the new energies are non-local however,
thus necessitating an extension of standard level set methods.
Promising experimental results are obtained using real
images. |
|
haut de la page
5 Rapports de recherche et Rapports techniques |
1 - A higher-order active contour model of a `gas of circles' and its application to tree crown extraction.
P. Horvath et I. H. Jermyn et Z. Kato et J. Zerubia. Research Report 6026, INRIA, France, novembre 2006.
Mots-clés : Extraction de Houppiers, Aerial images, Ordre superieur, Contour actif, Gaz de cercles, Forme.
@TECHREPORT{Horvath05,
|
| author |
= |
{Horvath, P. and Jermyn, I. H. and Kato, Z. and Zerubia, J.}, |
| title |
= |
{A higher-order active contour model of a `gas of circles' and its application to tree crown extraction}, |
| year |
= |
{2006}, |
| month |
= |
{novembre}, |
| institution |
= |
{INRIA}, |
| type |
= |
{Research Report}, |
| number |
= |
{6026}, |
| address |
= |
{France}, |
| url |
= |
{http://hal.inria.fr/inria-00115631}, |
| pdf |
= |
{ftp://ftp-sop.inria.fr/ariana/Articles/2006_Horvath05.pdf}, |
| keyword |
= |
{Extraction de Houppiers, Aerial images, Ordre superieur, Contour actif, Gaz de cercles, Forme} |
| } |
Abstract :
Many image processing problems involve identifying the region in the image domain occupied by a given entity in the scene. Automatic solution of these problems requires models that incorporate significant prior knowledge about the shape of the region. Many methods for including such knowledge run into difficulties when the topology of the region is unknown a priori, for example when the entity is composed of an unknown number of similar objects. Higher-order active contours (HOACs) represent one method for the modelling of non-trivial prior knowledge about shape without necessarily constraining region topology, via the inclusion of non-local interactions between region boundary points in the energy defining the model. The case of an unknown number of circular objects arises in a number of domains, \eg medical, biological, nanotechnological, and remote sensing imagery. Regions composed of an a priori unknown number of circles may be referred to as a `gas of circles'. In this report, we present a HOAC model of a `gas of circles'. In order to guarantee stable circles, we conduct a stability analysis via a functional Taylor expansion of the HOAC energy around a circular shape. This analysis fixes one of the model parameters in terms of the others and constrains the rest. In conjunction with a suitable likelihood energy, we apply the model to the extraction of tree crowns from aerial imagery, and show that the new model outperforms other techniques. |
|
2 - Higher-Order Active Contour Energies for Gap Closure.
M. Rochery et I. H. Jermyn et J. Zerubia. Rapport de Recherche 5717, INRIA, France, octobre 2005.
Mots-clés : Reseaux routiers, Continuity, Gap closure, Ordre superieur, Contour actif, Forme.
@TECHREPORT{RR_5717,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Higher-Order Active Contour Energies for Gap Closure}, |
| year |
= |
{2005}, |
| month |
= |
{octobre}, |
| institution |
= |
{INRIA}, |
| type |
= |
{Research Report}, |
| number |
= |
{5717}, |
| address |
= |
{France}, |
| url |
= |
{http://hal.inria.fr/inria-00070300/fr/}, |
| pdf |
= |
{https://hal.inria.fr/file/index/docid/70300/filename/RR-5717.pdf}, |
| ps |
= |
{http://hal.inria.fr/docs/00/07/03/00/PS/RR-5717.ps}, |
| keyword |
= |
{Reseaux routiers, Continuity, Gap closure, Ordre superieur, Contour actif, Forme} |
| } |
Résumé :
L'un des principaux problèmes lors de l'extraction de réseaux
linéiques dans des images, et en particulier l'extraction de réseaux
routiers dans des images de télédétection, est l'existence d'interruptions
dans les données, causées, par exemple, par des occultations. Ces
interruptions peuvent mener à des trous dans le réseau extrait qui
n'existent pas dans le réseau réel. Dans ce rapport, nous décrivons une
énergie de contour actif d'ordre supérieur qui, en plus de favoriser les
régions composées de bras fins et connectés entre eux, inclut un terme d'a
priori qui pénalise les configurations du réseau où des extremités proches
et se faisant face apparaissent. L'apparition dans le réseau extrait de ces
configurations est donc moins probable. Si des extremités proches et se
faisant face apparaissent pendant l'évolution par descente de gradient
utilisée pour minimiser l'énergie, le nouveau terme dans l'énergie crée une
attraction entre ces extremités, qui se rapprochent donc l'une de l'autre
et se rejoignent, fermant ainsi le trou entre elles. Pour minimiser
l'énergie, nous développons des techniques spécifiques pour traiter les
derivées d'ordre élevé qui apparaissent dans l'équation de descente de
gradient. Nous présentons des résultats d'extraction automatique de réseaux
routiers à partir d'images de télédétection, montrant ainsi la capacité du
modèle à surmonter les interruptions. |
Abstract :
One of the main difficulties in extracting line networks from
images, and in particular road networks from remote sensing images, is the
existence of interruptions in the data caused, for example, by occlusions.
These can lead to gaps in the extracted network that do not correspond to
gaps in the real network. In this report, we describe a higher-order active
contour energy that in addition to favouring network-like regions composed
of thin arms joining at junctions, also includes a prior term that
penalizes network configurations containing `nearby opposing extremities',
and thereby makes their appearance in the extracted network less likely. If
nearby opposing extremities form during the gradient descent evolution used
to minimize the energy, the new energy term causes the extremities to
attract one another, and hence to move towards one another and join, thus
closing the gap. To minimize the energy, we develop specific techniques to
handle the high-order derivatives that appear in the gradient descent
equation. We present the results of automatic extraction of networks from
real remote-sensing images, showing the ability of the model to overcome
interruptions. |
|
3 - Higher Order Active Contours.
M. Rochery et I. H. Jermyn et J. Zerubia. Rapport de Recherche 5656, INRIA, France, août 2005.
Mots-clés : Contour actif, Ordre superieur, Reseaux routiers, Forme, A priori.
@TECHREPORT{RR_5656,
|
| author |
= |
{Rochery, M. and Jermyn, I. H. and Zerubia, J.}, |
| title |
= |
{Higher Order Active Contours}, |
| year |
= |
{2005}, |
| month |
= |
{août}, |
| institution |
= |
{INRIA}, |
| type |
= |
{Research Report}, |
| number |
= |
{5656}, |
| address |
= |
{France}, |
| url |
= |
{https://hal.inria.fr/inria-00070352}, |
| pdf |
= |
{https://hal.inria.fr/file/index/docid/70352/filename/RR-5656.pdf}, |
| ps |
= |
{https://hal.inria.fr/docs/00/07/03/52/PS/RR-5656.ps}, |
| keyword |
= |
{Contour actif, Ordre superieur, Reseaux routiers, Forme, A priori} |
| } |
Résumé :
Nous introduisons une nouvelle classe de contours actifs qui offre des perspectives intéressantes pour la modélisation des régions et des formes, et nous appliquons un cas particulier de ces modèles à l'extraction de réseaux linéiques dans des images satellitaires et aériennes. Les nouveaux modèles sont des fonctionnelles polynômiales arbitraires sur l'espace des contours, et généralisent ainsi les fonctionnelles linéaires utilisées dans les modèles classiques de contours actifs. Alors que les fonctionnelles classiques s'écrivent avec de simples intégrales sur le contour, les nouvelles énergies sont définies comme des intégrales multiples, décrivant ainsi des interactions de longue portée entre les différents ensembles de points du contour. Utilisées comme des termes d'a priori, les fonctionnelles décrivent des familles de contours aux propriétés géométriques complexes, sans faire référence à une forme spécifique et sans nécessiter l'estimation de la position. Utilisées comme des termes d'attache aux données, elles permettent de décrire des interactions multi-points entre le contour et les données. Afin de minimiser ces énergies, nous adoptons la méthodologie des courbes de niveau. Les forces dérivées des énergies sont cependant non locales, et nécessitent une extension des méthodes de courbes de niveau standard. Les réseaux sont une famille de formes d'une grande importance dans de nombreuses applications et en particulier en télédétection. Pour les modéliser, nous faisons un choix particulier d'énergie quadratique qui décrit des structures branchées et nous ajoutons un terme d'attache aux données qui lie les données et la géométrie du contour au niveau des paires de points du contour. Des résultats d'extraction prometteurs sont montrés sur des images réelles. |
Abstract :
We introduce a new class of active contour models that hold great promise for region and shape modelling, and we apply a special case of these models to the extraction of road networks from satellite and aerial imagery. The new models are arbitrary polynomial functionals on the space of boundaries, and thus greatly generalize the linear functionals used in classical contour energies. While classical energies are expressed as single integrals over the contour, the new energies incorporate multiple integrals, and thus describe long-range interactions between different sets of contour points. As prior terms, they describe families of contours that share complex geometric properties, without making reference to any particular shape, and they require no pose estimation. As likelihood terms, they can describe multi-point interactions between the contour and the data. To optimize the energies, we use a level set approach. The forces derived from the new energies are non-local however, thus necessitating an extension of standard level set methods. Networks are a shape family of great importance in a number of applications, including remote sensing imagery. To model them, we make a particular choice of prior quadratic energy that describes reticulated structures, and augment it with a likelihood term that couples the data at pairs of contour points to their joint geometry. Promising experimental results are shown on real images. |
|
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