Departments:
- - Applied Informatics
- - Image Processing and Computer Graphics
- - Foundations of Computer Science
- - Computer Algorithms and Artificial Intelligence
- - Software Engineering
- - Research Group on Artificial Intelligence
[University of Szeged]
Higher Order Active Contours - the `Gas of Circles' Shape Prior
 | Members: Peter Horvath, Zoltan Kato Funded by
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Description
The ‘gas of circles’ (GOC) model is a tool to describe a set of circles with an approximately fixed radius. The model is based on the recently introduced ‘higher-order active contour’ (HOAC) framework. For certain ranges of the HOAC parameters, the model creates stable circles with an approximately fixed radius instead of networks. The general ‘gas of circles’ model has many potential applications in varied domains, but it suffers from a drawback: the local minima corresponding to circles can trap the gradient descent algorithm, thus producing phantom circles even with no supporting data. We solved the problem of phantom circles by calculating, via a Taylor expansion of the energy, parameter values that make the circles into inflection points rather than minima. We developed an alternative formulation of the ‘gas of circles’, based on the ‘phase field’ framework. We address the tree crown extraction problem by constructing a phase field model of a ‘gas of circles’. The images we used are color-infrared (CIR) and panchromatic images. We introduced two data models. The first describes the use of only one band of the three available bands. The model is based on the image gradient and on Gaussian distributions. Our second data model makes use of all three bands in the CIR images. Experiments show that the models outperform other traditional methods. The models can also be applied to the detection of other circular objects, e.g. in biology, nano-technology, medical imaging, teledetection.
Results
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Publications
- Péter Horváth. A Multispectral Data Model for Higher-Order Active Contours and its Application to Tree Crown Extraction. In Proceedings of the Advanced Concepts for Intelligent Vision Systems, volume 4678 of Lecture Notes in Computer Science, Delft, Netherlands, pages 200-211, August 2007.
- Péter Horváth and Ian Jermyn. A 'gas of Circles' Phase Field Model and its Application to Tree Crown Extraction. In Proceedings of the European Signal Processing Conference (EUSIPCO), Poznan, Poland, September 2007.
- Péter Horváth and Ian Jermyn. A New Phase Field Model of a 'gas of Circles' for Tree Crown Extraction from Aerial Images. In Proceedings of International Conference on Computer Analysis of Images and Patterns, volume 4673 of Lecture Notes in Computer Science, Vienna, Austria, pages 702-709, August 2007.
- Peter Horvath, Ian Jermyn, Zoltan Kato, and Josiane Zerubia. A Higher-Order Active Contour Model for Tree Detection. In Proceedings of International Conference on Pattern Recognition, volume 2, Hong Kong, China, pages 130-133, August 2006. IAPR, IEEE.
- Peter Horvath, Ian Jermyn, Zoltan Kato, and Josiane Zerubia. An improved `gas of circles' higher-order active contour model and its application to tree crown extraction. In Prem Kalra and Shmuel Peleg, editors, Proceedings of Indian Conference on Computer Vision, Graphics and Image Processing, volume 4338 of Lecture Notes in Computer Science, Madurai, India, pages 152-161, December 2006. Springer.
- Peter Horvath, Ian Jermyn, Zoltan Kato, and Josiane Zerubia. A Higher-Order Active Contour Model of a `Gas of Circles' and its Application to Tree Crown Extraction. Research Report 6026, INRIA, Sophia Antipolis, France, November 2006. [PDF]
- Péter Horváth. The 'Gas of Circles' Model and its Application to Tree Crown Extraction. PhD Thesis, University of Nice - Sophia Antipolis and University of Szeged. December 2007. [PDF]
- Peter Horvath, Ian Jermyn, Zoltan Kato, and Josiane Zerubia. A higher-order active contour model of a `gas of circles' and its application to tree crown extraction. Pattern Recognition, 42(5):699-709, May 2009.