Search results for "Image processing"

Space-Frequency Quantization for Image Compression With Directionlets

2007

The standard separable 2-D wavelet transform (WT) has recently achieved a great success in image processing because it provides a sparse representation of smooth images. However, it fails to efficiently capture 1-D discontinuities, like edges or contours. These features, being elongated and characterized by geometrical regularity along different directions, intersect and generate many large magnitude wavelet coefficients. Since contours are very important elements in the visual perception of images, to provide a good visual quality of compressed images, it is fundamental to preserve good reconstruction of these directional features. In our previous work, we proposed a construction of critic…

Micro-architecture of three-dimensional porous scaffolds evaluated via image processing technique

2011

Multi-modal Image Registration Using Fuzzy Kernel Regression

2009

This paper presents a study aimed to the realization of a novel multiresolution registration framework. The transformation function is computed iteratively as a composition of local deformations determined by the maximization of mutual information. At each iteration, local transformations are joint together using fuzzy kernel regression. This technique represents the core of the mothod and it's formally described from a probabilistic perspective. It avoids blocking artifacts and allows to keep the final deformation spatially congruent and smooth. Both qualitative and quantitative experimental results show that this approach is equally effective for registering datasets acquired from both si…

Active lighting applied to three dimensional reconstruction of specular metallic surfaces by polarization imaging

2005

This thesis deals with a new automated tridimensional inspection system for specular metallic surfaces, based on polarization analysis. We first present an extension of the ‘Shape from Polarization' method for dielectric to metallic surfaces. After being reflected, an unpolarized light wave becomes partially linearly polarized, depending on the surface normal and on the refractive index of the media it impinges on. Hence, by measuring the polarization parameters of the reflected light, the surface normals are computed. The ambiguity concerning the normals orientation is solved here with a new active lighting system. Then, we describe and compare numerical methods for reconstructing the trid…

IP 3 signalling regulates exogenous RNA i in C aenorhabditis elegans

2015

RNA interference (RNAi) is a widespread and widely exploited phenomenon. Here, we show that changing inositol 1,4,5-trisphosphate (IP3) signalling alters RNAi sensitivity in Caenorhabditis elegans. Reducing IP3 signalling enhances sensitivity to RNAi in a broad range of genes and tissues. Conversely up-regulating IP3 signalling decreases sensitivity. Tissue-specific rescue experiments suggest IP3 functions in the intestine. We also exploit IP3 signalling mutants to further enhance the sensitivity of RNAi hypersensitive strains. These results demonstrate that conserved cell signalling pathways can modify RNAi responses, implying that RNAi responses may be influenced by an animal's physiology…

VERS UNE ARCHITECTURE UNIFIÉE ET ZÉRO TEMPS MORT POUR L'INSTRUMENTATION NUCLÉAIRE

2014

National audience; Dans l’instrumentation nucléaire, et d’autres domaines tels que les applications de la physique des particules, l’analyse de signaux médicaux (Tomographie par Emission de Positons (TEP), Electro-EncephaloGraphie (EEG)) ou la détection de signaux radar, le signal mesuré est composé d’impulsions dont la date d’arrivée est aléatoire, et dont l’amplitude et la durée sont non-d´eterministes. La grande variété d’applications nécessite de disposer d’une architecture flexible pouvant être aisément reprogrammée. De plus, l’exigence de mesures en temps réel impose de disposer d’une grande capacité de calcul et de bande passante pour la mise en forme et l’extraction des caractéristi…

On modified α-ϕ-fuzzy contractive mappings and an application to integral equations

2016

Abstract We introduce the notion of a modified α-ϕ-fuzzy contractive mapping and prove some results in fuzzy metric spaces for such kind of mappings. The theorems presented provide a generalization of some interesting results in the literature. Two examples and an application to integral equations are given to illustrate the usability of our theory.

Semi-blind Source Extraction Methods: Application to the measurement of non-contact physiological signs

2018

Non-contact physiological measurements are highlydesirable in many biomedical fields such asdiagnosis of infants, geriartic patients, patients withextreme physical trauma, and fitness and well-being.Remote photoplethysmography is increasingly beingused for non-contact measurement of heart rate fromvideos which is one of the most common biomedicalproperty required for most medical diagnosis. Oneof the common techniques for performing remotephotoplethysmography involves using Blind SourceSeparation (BSS) methods to extract the cardiacsignal from video data.In this context, the objective of this thesis is todevelop different methods in the field of extractionand separation of sources by improv…

Hume’s Guillotine in Designing Ethically Intelligent Technologies

2020

Intelligent machines can follow ethical rules in their behaviour. However, it is less clear whether intelligent systems can also create new ethical principles. The former position can be called weak ethical AI and the latter strong ethical AI. Hume’s guillotine which claims that one cannot derive values from facts appears to be a fundamental obstacle to strong ethical AI. The analysis of human ethical information processes provides clarity to the possibility of strong ethical AI. Human ethical information processing begins with positive of negative emotions associated to situations. Situations can be seen as consequences of actions and for this reason people can define rules about acceptabi…

Large-scale nonlinear dimensionality reduction for network intrusion detection

2017

International audience; Network intrusion detection (NID) is a complex classification problem. In this paper, we combine classification with recent and scalable nonlinear dimensionality reduction (NLDR) methods. Classification and DR are not necessarily adversarial, provided adequate cluster magnification occurring in NLDR methods like $t$-SNE: DR mitigates the curse of dimensionality, while cluster magnification can maintain class separability. We demonstrate experimentally the effectiveness of the approach by analyzing and comparing results on the big KDD99 dataset, using both NLDR quality assessment and classification rate for SVMs and random forests. Since data involves features of mixe…