Search results for "Engineering sciences"
showing 10 items of 2347 documents
Analysis of the performance of the TES algorithm over urban areas
2014
International audience; The temperature and emissivity separation (TES) algorithm is used to retrieve the land surface emissivity (LSE) and land surface temperature (LST) values from multispectral thermal infrared sensors. In this paper, we analyze the performance of this methodology over urban areas, which are characterized by a large number of different surface materials, a variability in the lowest layer of the atmospheric profiles, and a 3-D structure. These specificities induce errors in the LSE and LST retrieval, which should be quantified. With this aim, the efficiency of the TES algorithm over urban materials, the atmospheric correction, and the impact of the 3-D architecture of urb…
Fast prototyping of parallel image processing applications using functional skeletons
1999
We present SKiPPER, a software dedicated to the fast prototyping of vision algorithms on MIMD/DM platforms. This software is based upon the concept of algorithmic skeletons, i.e. higher order program constructs encapsulating recurring forms of parallel computations and hiding their low-level implementation details. Examples of such skeletons in low- to mid-level image processing include such as geometric decompositions, data or task farming. Each skeleton is given an architecture-independant functional (but executable) specification, a portable implementation as a process template and an analytic performance model. The source program is a purely functional specification of the algorithm in …
Digital Correlation Method Based on Micro-geometrical Texture Pattern for Strain Field Measurement
2011
International audience; Image correlation methods are widely used in experimental mechanics to obtain displacement field measurements. Currently, these methods are applied using digital images of the initial and deformed surfaces sprayed with black or white paint. Speckle patterns are then captured and the correlation is performed with a high degree of accuracy to an order of 0.01 pixels. In 3D, however, stereo-correlation leads to a lower degree of accuracy. Correlation techniques are based on the search for a sub-image (or pattern) displacement field. The work presented in this paper introduces a new correlation-based approach for 3D displacement field measurement that uses an additional …
Supercontinuum Generation and Intermodal Four-Wave Mixing in a Step-Index Few-Mode Fibre
2019
International audience; The complex spatiotemporal dynamics of nonlinear light propagation in multimode fibers (MMFs) has recently witnessed a renewed interest because of their experimental realization in emerging key areas of laser physics and fiber optics [1]. Specifically, MMFs have a number of linear and nonlinear optical properties that make them very attractive to investigate new spatiotemporal effects fundamentally different from standard single-mode fibers. These include the observation of multimode solitons [2], intermodal four-wave mixing (FWM) [3], geometric parametric instabilities [4], spatial beam self-cleaning [5], and the generation of supercontinuum (SC) light when pumping …
A2Ba: Adaptive Background Modelling for Visual Aerial Surveillance Conditions
2015
International audience; Background modelling algorithms are widely used to define a part of an image that most time remains stationary in a video. In surveillance tasks, this model helps to recognize those outlier objects in an area under monitoring. Set up a background model on mobile platforms (UAVs, intelligent cars, etc.) is a challenging task due camera motion when images are acquired. In this paper, we propose A2Ba, a robust method to support instabilities caused by aerial images fusing different information about image motion. We used frame difference as first approximation, then age of pixels is estimated. This latter gives us an invariability level of a pixel over time. Gradient di…
Skin Parameter Map Retrieval from a Dedicated Multispectral Imaging System Applied to Dermatology/Cosmetology
2013
International audience; In vivo quantitative assessment of skin lesions is an important step in the evaluation of skin condition. An objective measurement device can help as a valuable tool for skin analysis. We propose an explorative new multispectral camera specifically developed for dermatology/cosmetology applications. The multispectral imaging system provides images of skin reflectance at different wavebands covering visible and near-infrared domain. It is coupled with a neural network-based algorithm for the reconstruction of reflectance cube of cutaneous data. This cube contains only skin optical reflectance spectrum in each pixel of the bidimensional spatial information. The reflect…
Structural characterization and optical constants of p-toluene sulfonic acid doped polyaniline and its composites of chitosan and reduced graphene-ox…
2020
Para-Toluene sulfonic acid doped polyaniline (PANI), PANI/chitosan composites, PANI/reduced graphene-oxide composites and a ternary composite comprising of PANI, chitosan and reduced graphene-oxide have synthesised via oxidative polymerisation of aniline by Ammonium peroxydisulfate (APS). FTIR, XRD, FESEM and UV-VIS techniques were performed for the confirmation of the successful synthesis. The fundamental optical parameters such as, complex refractive index, complex dielectric constants and optical conductivity of the PANI and the composites were investigated in the UV-VIS-NIR range. The results show a clear dependence on the constituent component such as sulphur as well as the absorbance …
Damage accumulation and life prediction in carbon fibre composite pressure vessels
2009
Composites and nanostructures
State of the art and prospects for halide perovskite nanocrystals
2021
Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of …
Identification of lipid accumulation in lacrimal gland from NOD mice
2008
International audience; Purpose: : The NOD mouse is an established animal model of the human disease, Sjögren’s syndrome. The lacrimal gland of male NOD mouse becomes significantly infiltrated with inflammatory cells by 12 weeks of age. Dacryadenitis is associated with massive lipid deposition in the lacrimal acinar cells, a process which starts by 6 weeks of age and is accompanied by onset of inflammatory infiltrates. The aim of this study was to identify the lipids that accumulate in lacrimal glands from NOD mice. Methods: : Lacrimal glands were excised from 12-week-old male NOD (n = 8) and BALB/c mice (n = 10). Lipids were extracted and lipid class distribution examined. Then the lipid c…