Search results for "Signal and Image processing"
showing 10 items of 454 documents
Multi-pixel Geiger mode imager for medical application
2013
International audience; Nowadays, there are two types of sensors to detect the low luminous flux, PMT (Photomultiplier Tube) and Geiger-APD (Geiger Avalanche Photodiode). The domain of Geiger-APD has reached an advanced development in the last years. The basic idea of this structure consists in polarizing an APD in Geiger-mode by applying a voltage beyond its breakdown voltage. In this case of polarization, the APD is working in a special mode and is able to detect the single photon. The theory of detection of single photon using this detector has been invented in the beginning of 90's and developed for detection of low light intensity. By using this kind of photodiode in the Geiger-mode, w…
Phase Space Reconstruction of an Experimental Cardiac Electrical Signal
2014
International audience; Cardiac arrhythmias are very common pathologies which can be treated either by medications, invasive ablation procedures or device implantations. In order to improve theses treatments, clinical and experimental models are used to test new drugs. In this context, in vitro cultures of cardiac cells represent valuable models to study the mechanism of the arrhythmias at the cellular level. In this paper, we investigate the stability and robustness of an experimental model in normal and under external stimulation conditions. Phase space reconstructions of attractors in normal and arrhythmic cases are performed after characterizing the nonlinearity of the model, computing …
Visualization of spectral images: a comparative study
2011
International audience; The dimensionality reduction of spectral images for visualization has been a quite active area of research recently. Given the variety of existing approaches, it can be very chal- lenging to understand the actual advantages of one over another, especially in the absence of a very specific application. Moreover, there is no consensus on how to evaluate the general efficiency of such a method. In this paper, we propose a comparison framework not only to compare such techniques, but also to measure their intrinsic properties in terms of naturalness and informative content.
Image Encryption/Decryption system based on an oscillatory cellular nonlinear network
2008
International audience
Implicit motor learning in discrete and continuous tasks: Toward a possible explanation of discrepant results
2009
Abstract
Vineyard leaf roughness characterization by computer vision and cloud computing technics
2010
International audience; In the context of vineyard leaf roughness analysis for precision spraying applications, this article deals with its characterization by computer vision and cloud computing techniques. The techniques merge feature extraction, linear or nonlinear dimensionality reduction techniques and several kinds of classification methods. Different combinations are processed and their performances compared in terms of classification error rate, in order to find the best association. However these combinations are hardly processed because of the lack of computing power and the prohibitive time consumption of the algorithms. To overcome these difficulties, we propose a solution: the …
Weed detection by aerial imaging: impact of soil, crop and weed spectral mixing
2015
International audience; This study aims to evaluate spectral information potential of images captured with a UAV, for site specific weed management. The image acquisition chain was modeled in order to compute the digital values of image pixels, according to the field conditions and objects lying on the ground surface projected in the pixels. The object spectra are mixed in the same pixel to estimate the impact of the spatial resolution of the image. The classification potential into crop, weed and soil classes was studied usinf simulations based on the present multispectral sensor characteristics and according to different mixing rates.
Cardiac arrhythmia induced by hypothermia in a cardiac model in vitro
2013
nouvelle version avec l'article complet; International audience; The neurological damage after cardiac arrest (CA) constitutes a big challenge of hospital discharge since years. The therapeutic hypothermia therapy (34°C-32°C) has shown its benefit to reduce cerebral oxygen demand and improve neurological outcomes after the cardiac arrest. Despite the fact that induced hypothermia after CA has been shown to increase the hospital survival rate, it can have many adverse effects, among which the cardiac arrhythmia generation represents an important part (up to 34%, according different clinical studies). Compared to studies in vivo, cardiac culture in vitro provides a better spatial resolution a…
Remaillage semi-régulier pour les maillages surfaciques triangulaires : un état de l'art
2010
National audience; Les maillages surfaciques triangulaires sont désormais couramment utilisés pour modéliser des formes tridimensionnelles. Beaucoup de ces modèles géométriques sont obtenus à partir de techniques de numérisation scanner ou de représentations implicites (isosurfaces). Ainsi la géométrie de ces maillages est souvent très dense (sur-échantillonnage) et leur connectivité arbitraire (irrégularité du voisinage des sommets). Il est alors souvent nécessaire de les remailler afin de réduire leur complexité (simplification), améliorer la qualité des triangles produits, optimiser l'échantillonnage de la géométrie ou encore rendre la connectivité la plus régulière possible. Concernant …
Imagerie polarimétrique : principes et applications.
2016
National audience