Nicolas Widynski

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In this paper a new algorithm to compute the component tree is presented. As compared to the state-of-the-art, this algorithm does not use excessive memory and is able to work efficiently on images whose values are highly quantized or even with images having floating values. We also describe how it can be applied to astronomical data to identify relevant(More)
In this paper, we propose an algorithm to detect smooth local symmetries and contours of ribbon-like objects in natural images. The detection is formulated as a spatial tracking task using a particle filtering approach, extracting one part of a structure at a time. Using an adaptive local geometric model, the method can detect straight reflection symmetries(More)
Edge detection remains an active problem in the image processing community, because of the high complexity of natural images. In the last decade, Desolneux et al. proposed a novel parameter free detection approach, based on the Helmhotz principle. Applied to the edge detection problem, this means that observing a true edge in random and independent(More)
In this paper, we propose a novel method to introduce structural spatial information in particle filters. This information, expressed as spatial relations such as orientation and distance, is modeled in a fuzzy set framework, and is introduced in the dynamics in order to model the potential changes from one instant to the next one. The fuzzy modeling(More)
We investigate the contour detection task in complex natural images. We propose a novel contour detection algorithm which jointly tracks at two scales small pieces of edges called edgelets. This multiscale edgelet structure naturally embeds semi-local information and is the basic element of the proposed recursive Bayesian modeling. Prior and transition(More)
This paper investigates the speckle spot detection task in ultrasound images. Speckle spots are described by structural criteria: dimensions, shape, and topology. We propose to represent the image using a morphological inclusion tree, from which speckle spots are detected using their structural appearance. This makes the method independent of contrast, and(More)
This paper investigates the task of tracking and strain estimation of arteries in intravascular ultrasound images. A tracking method is proposed to extract the inner and the outer contours of the vessel wall (lumen/intima-media and intima-media/adventitia interfaces, respectively), and the deformations along them. This estimation is carried out by a non(More)
Dealing with multi-object tracking in a particle filter raises several issues. A first essential point is to model possible interactions between objects. In this article, we represent these interactions using a fuzzy formalism, which allows us to easily model spatial constraints between objects, in a general and formal way. The second issue addressed in(More)
In this paper, we propose a novel method to introduce spatial information in particle filters. This information may be expressed as spatial relations (orientation, distance, etc.), velocity, scaling, or shape information. Spatial information is modeled in a generic fuzzy-set framework. The fuzzy models are then introduced in the particle filter and(More)