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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Study of the Far Infrared Emission of Nearby Spiral Galaxies

Drouhet, Willie 07 November 2013 (has links) (PDF)
In my PHD work I explored the links between the physical properties of interstellar dust and other components of nearby spiral galaxies especially their stellar content. I worked on 46 disk galaxies from KINGFISH with IRAC/MIPS/PACS/SPIRE maps (3.6 - 500 microns). A bias is usually introduced in estimating disk orientations by using only a single surface brightness isophote. Thus I devised different surface brightness levels separated by constant steps in surface brightness and extracted isophotes at these levels in all FIR maps as well as in all IRAC 4.5 microns maps. To further assess the coherence of the shapes of isophotes across galactic disks, I built a quantitative indicator of the difference in shape between two ellipses with same center and same semi-major axis.I defined an acceptable level of difference between isophote shapes, by comparing disk orientations found in litterature. Using this level, I found regions inside the galactic disks where the isophotal shapes are similar. From these, I extracted one disk orientation per wavelength band. I found in the vast majority of the disk galaxy maps, be it dominated by stellar or dust emission, that a large fraction of the isophotes I extracted are coherent with the idea of an underlying disk. Comparing, for each galaxy, disk orientations extracted at all wavelengths, I found evidence in 20 galaxies out of 46, that on radial ranges as large as 1/3 of the visible disk (as measured by R25), the shapes of isophotes are morphologically similar. Thus for these 20 galaxies I devised consistent disk orientations both for the stellar and dust content. These 20 galaxies are less luminous, less emitting in the IR w.r.t. the optical, less barred, and characterized by later stage types than average. I also found that the disk orientations devised by my photometric method yield results more similar to H-alpha kinematic orientations than other photometric studies based on a single isophote level.Using the orientations I found and H-alpha dynamics disk orientations, I averaged azimuthally surface brightnesses to produce radial spectral energy distributions (SED) profiles. Once fitted with a cosmic dust emission model, they resulted in radial profiles of dust and stellar content properties. I found the dust intercepted power to be proportionnal to the product of the total dust mass and the average ISRF shining on dust. This former quantity is better correlated with the bolometric stellar luminosity than any of the dust mass or the dust heating ISRF separately. Thus the old stellar populations may be an important heating source for dust. The power intercepted by dust is also very well correlated with the total infrared power. The dust intercepts a larger quantity of power coming from stars in more actively star forming galaxies.Dust exhibit radial mass surface density profiles less well described by Sersic functions than stellar ones. When both profiles are well fitted by Sersic functions, stellar density profiles have smaller half mass radii than the isophotal optical radius (R25) separately in later type galaxies, but also in more quiescent galaxies. Sersic index and half mass radius distributions have larger widths for dust than for stellar surface density profiles.I also found that the ratio of dust over stellar surface density is an important factor to explain the variations with galactic morphological type of the ratio of dust intercepted power over the power emitted by old stellar populations. This later link could be intertwined with spiral structure strength in stage types later than 2.
22

Multi-modal, Multi-Domain Pedestrian Detection and Classification : Proposals and Explorations in Visible over StereoVision, FIR and SWIR

Miron, Alina Dana 16 July 2014 (has links) (PDF)
The main purpose of constructing Intelligent Vehicles is to increase the safety for all traffic participants. The detection of pedestrians, as one of the most vulnerable category of road users, is paramount for any Advance Driver Assistance System (ADAS). Although this topic has been studied for almost fifty years, a perfect solution does not exist yet. This thesis focuses on several aspects regarding pedestrian classification and detection, and has the objective of exploring and comparing multiple light spectrums (Visible, ShortWave Infrared, Far Infrared) and modalities (Intensity, Depth by Stereo Vision, Motion).From the variety of images, the Far Infrared cameras (FIR), capable of measuring the temperature of the scene, are particular interesting for detecting pedestrians. These will usually have higher temperature than the surroundings. Due to the lack of suitable public datasets containing Thermal images, we have acquired and annotated a database, that we will name RIFIR, containing both Visible and Far-Infrared Images. This dataset has allowed us to compare the performance of different state of the art features in the two domains. Moreover, we have proposed a new feature adapted for FIR images, called Intensity Self Similarity (ISS). The ISS representation is based on the relative intensity similarity between different sub-blocks within a pedestrian region of interest. The experiments performed on different image sequences have showed that, in general, FIR spectrum has a better performance than the Visible domain. Nevertheless, the fusion of the two domains provides the best results. The second domain that we have studied is the Short Wave Infrared (SWIR), a light spectrum that was never used before for the task of pedestrian classification and detection. Unlike FIRcameras, SWIR cameras can image through the windshield, and thus be mounted in the vehicle's cabin. In addition, SWIR imagers can have the ability to see clear at long distances, making it suitable for vehicle applications. We have acquired and annotated a database, that we will name RISWIR, containing both Visible and SWIR images. This dataset has allowed us to compare the performance of different pedestrian classification algorithms, along with a comparison between Visible and SWIR. Our tests have showed that SWIR might be promising for ADAS applications,performing better than the Visible domain on the considered dataset. Even if FIR and SWIR have provided promising results, Visible domain is still widely used due to the low cost of the cameras. The classical monocular imagers used for object detectionand classification can lead to a computational time well beyond real-time. Stereo Vision providesa way of reducing the hypothesis search space through the use of depth information contained in the disparity map. Therefore, a robust disparity map is essential in order to have good hypothesis over the location of pedestrians. In this context, in order to compute the disparity map, we haveproposed different cost functions robust to radiometric distortions. Moreover, we have showed that some simple post-processing techniques can have a great impact over the quality of the obtained depth images.The use of the disparity map is not strictly limited to the generation of hypothesis, and couldbe used for some feature computation by providing complementary information to color images.We have studied and compared the performance of features computed from different modalities(Intensity, Depth and Flow) and in two domains (Visible and FIR). The results have showed that the most robust systems are the ones that take into consideration all three modalities, especially when dealing with occlusions.
23

Efeitos in vitro da radiação infravermelha longa em fibroblastos humanos oriundos do leito de feridas crônicas de etiologia venosa / In vitro effects of Far Infrared Radiation on human venous ulcer fibroblasts

Altran, Silvana Cereijido 12 February 2019 (has links)
Úlceras decorrentes de disfunções venosas são comuns na prática clínica. Fatores como hipóxia, infecção, acúmulo de fibroblastos senescentes, metabolismo anormal de colágeno e desequilíbrio entre produção e absorção de matriz extracelular contribuem para a cronicidade dessas lesões. Até o momento, não existe tratamento ideal para essas úlceras. A radiação infravermelha longa (FIR) tem sido proposta como opção. Diversos estudos descrevem efeitos antimicrobiano e anti-inflamatório, melhora na circulação sanguínea, regeneração de colágeno, aumento na proliferação de fibroblastos e expressão de TGF-beta, e aumento da síntese de óxido nítrico (NO), que tem papel importante em todas as fases da cicatrização. O objetivo deste estudo foi avaliar, por imunoensaios, a ação de substratos têxteis emissores de radiação infravermelha longa (FIR), em associação ou não à prata (FIR+Ag), sobre cultura de fibroblastos oriundos de úlcera venosa (venous ulcer fibroblasts VUFs) quanto a citotoxicidade, expressão de vimentina, colágeno dos tipos I e III, iNOS e VEGF, além do potencial antimicrobiano sobre cepas de bactérias frequentemente encontradas no leito de úlceras venosas. Ao que parece, o aditivo FIR sozinho, ou em combinação com prata, não exerceu efeito citotóxico sobre fibroblastos humanos (VUF). Houve aumento na expressão de vimentina em relação ao controle em todos os estímulos avaliados. Também foi observado aumento da expressão de iNOS estimulado pela prata. Não ocorreu aumento da expressão de VEGF e colágeno do tipo I e tipo do III. O efeito antimicrobiano de FIR foi comparável ao efeito classicamente descrito para a utilização de prata. Assim, acreditamos que o emprego de produtos têxteis emissores de FIR como curativos seja uma possível opção para o tratamento de úlceras venosas / Ulcers resulting from venous dysfunctions are common in clinical practice. Factors such as hypoxia, infection, accumulation of senescent fibroblasts, abnormal collagen metabolism and imbalance between production and absorption of extracellular matrix contribute to the chronicity of these sores. There is no ideal treatment for those ulcers. Far Infrared Radiation (FIR) has been proposed as a treatement option. Several studies describe antimicrobial and anti-inflammatory effects, improvement in blood circulation, regeneration of collagen, increased proliferation of skin fibroblasts, higher expression of TGF-beta and increased synthesis of nitric oxide (NO), which plays an important role in all phases of the wound healing process. The aim of this study was to evaluate the action of textile emitting FIR substrates, whether containing silver or not (FIR+Ag), on the culture of venous ulcer fibroblasts (VUFs) regarding to: cytotoxicity, vimentin, types I and III collagen, iNOS and VEGF expression as well as the antimicrobial potential on strains of bacteria frequently found in venous ulcers. Our results proved that FIR additives alone, or in combination with silver, did not exert a cytotoxic effect on human fibroblasts (VUF). There was an increase in vimentin expression in relation to the control in all evaluated stimuli. Increased stimulation of iNOS expression by silver was observed. No increase in the expression of VEGF and nor collagen types I and III was observed. An antimicrobial effect of FIR comparable to the effect classically described for the use of silver has been verified. Thus, we believe that the use of FIR-emitting textile products as curatives is a possible option for the treatment of venous ulcers
24

Low-Energy Charge and Spin Dynamics in Quantum Confined Systems

Rice, William 06 September 2012 (has links)
Condensed matter systems exhibit a variety of dynamical phenomena at low energy scales, from gigahertz (GHz) to terahertz (THz) frequencies in particular, arising from complex interplay between charge, spin, and lattice. A large number of collective and elementary excitations in solids occur in this frequency range, which are further modified and enriched by scattering, interactions, and disorder. Recent advancements in spectroscopic methods for probing low-energy dynamics allow us to investigate novel aspects of charge and spin dynamics in solids. In this dissertation work, we used direct current (DC) conductivity, GHz, THz, and mid-infrared (MIR) techniques to provide significant new insights into interaction and disorder effects in low-dimensional systems. Specifically, we have studied temperature-dependent magnetoresistance (MR) and electron spin resonance (ESR) in single-wall carbon nanotubes (SWCNTs), intra-exciton scattering in InGaAs quantum wells, and high-field MIR-induced band gaps in graphene. Temperature-dependent resistance and MR were measured in an ensemble of SWCNTs from 0.3 to 350 K. The resistance temperature behavior followed a 3D variable range hopping (VRH) behavior from 0.3 to ~100 K. A positive MR was observed at temperatures above 25 K and could be fit with a spin-dependent VRH model; negative MR was seen at low temperatures. In the GHz regime, the ESR linewidth for SWCNTs was observed to narrow by as much as ~50% as the temperature was increased from 3 to 300 K, a phenomenon known as motional narrowing, suggesting that we are detecting the ESR of hopping spins. From the linewidth change versus temperature, we find the hopping frequency to be 285 GHz. For excitons in InGaAs quantum wells, we demonstrate the manipulation of intra-excitonic populations using intense, narrow-band THz pulses. The THz radiation temporarily quenches the 1s emission, which is then followed by an enhancement and subsequent decay of 2s emission. After the quenching, the 1s emission recovers and then eventually becomes enhanced, a demonstration of energy storage in intra-exciton states known as excitonic shelving. We show that the diffusive Coulomb scattering between the 2p and 2s states produces a symmetry breaking, leading to a THz-field-induced 1s-to-2s exciton population transfer.
25

Modal optical studies of multi-moded ultra-low-noise detectors in far-infrared

Chen, Jiajun January 2018 (has links)
In this thesis, I have developed a range of theoretical and numerical techniques for modelling the behaviour of partially coherent optical systems and multi-mode detectors. The numerical simulations were carried out for the ultra-low-noise Transition Edge Sensors (TESs) being proposed for use on the SAFARI instrument on the cooled aperture infrared space telescope SPICA (34 - 210 μm). The optical behaviour of the SAFARI system is described in terms of the optical modes of the telescope, as distinct from the optical modes of the detector. The performance of the TESs were assessed in terms of signal power, background power and photon noise. To establish a method for precisely characterising and calibrating ultra-low-noise TESs, a cryogenic test system was designed and engineered to measure the optical efficiencies of the SAFARI TESs. The multi-mode, partially coherent illumination conditions of the measurement system were engineered to be precisely the same as those of the telescope. A major difference between the test system and the telescope’s optics is that the telescope will have focusing elements, but the test system was designed to avoid focusing elements in order to keep the optical path as clean as possible. The theoretical formalism and numerical models were adapted accordingly to address this difference. The numerical simulations show that the test system could provide near identical optical performance as that of the telescope system even though the focusing elements were absent. I also performed experimental measurements to investigate the optical efficiencies of the multi-mode TESs. The detectors worked exceedingly well in all respects with satisfactory optical efficiencies. In addition, it has been shown that the optical model provides a good description of the optical behaviour of the test system and detectors. Further modal analysis was developed to study losses in the multi-mode horns. The optical behaviour of the waveguide-mounted thin absorbing films in the far-infrared was modelled using a mode-matching method.
26

Application de la spectroscopie térahertz à la détection de substances sensibles / Ultra broadband terahertz time domain spectroscopy - security application

Armand, Damien 07 July 2011 (has links)
Pour répondre aux questions que pose la faisabilité d’un dispositif de détection d’explosifsà l’aide de la technologie de spectroscopie térahertz, cette thèse a exploré troisaxes. Le premier a consisté à établir une base de données des signatures spectrales (indiceet absorption) d’une large gamme de matériaux d’intérêt pour ce type d’applications,à partir des données expérimentales que nous avons mesurées par spectroscopie dans ledomaine temporel. Nous avons identifié les matériaux montrant une signature spectralesignificative et nous avons aussi étudié l’effet des matériaux de dissimulation.Dans la seconde partie de ce travail, nous avons conçu et construit un banc de spectroscopieultra-large bande destiné à une meilleure identification spectrale des substances. Nousavons identifié les limites techniques de ce type de banc et donné les pistes pour atteindreles performances désirées.Ensuite, nous avons développé et validé un banc de spectroscopie en réflexion, de typegoniométrique, afin de détecter des signaux térahertz diffusés par des matériaux hétérogènes.Finalement, nous avons étudié les plasmons de surface dans le domaine térahertz, en vuede la détection de très faibles quantités de matière. / This PhD work was performed in view of using terahertz electromagnetic signals forthe detection and identification of dangerous and prohibited substances. In a first stage,a database of the terahertz properties (namely refractive index and absorption) of thesesubstances was created from the measurements we performed using terahertz time-domainspectroscopy. Then a large bandwidth terahertz time-domain set up has been built, togetherwith a goniometric-type set up that allows us recording signals scattered by roughor heterogeneous samples. Finally, we studied the excitation and propagation of surfaceplasmons in the terahertz domain, which may be used for the detection of small amountsof matter.
27

Fotometria e imageamento THz de fontes termicas e não-termicas / THz imaging and photometry of thermal and non-thermal sources

Melo, Arline Maria 11 July 2007 (has links)
Orientador: Jose Alexandre Diniz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-11T06:36:37Z (GMT). No. of bitstreams: 1 Melo_ArlineMaria_D.pdf: 17701586 bytes, checksum: b5160ad894463745fdeea0dae1f71065 (MD5) Previous issue date: 2007 / Resumo: Este trabalho apresenta importantes informações sobre tecnologia THz, atualmente considerada um desafio tecnológico e estado da arte em diversas áreas de desenvolvimento. Com o objetivo de formar um sistema imageador THz, ainda indisponível comercialmente, foram dispensados esforços em diferentes frentes. Câmeras para o infravermelho médio (8 ¿ 14 µm) foram adquiridas, caracterizadas e testadas, com resultados relevantes e inéditos em Física Solar, aplicação considerada para este trabalho. Filtros de malha ressonante para diversas bandas na região THz (centrados em 0,4, 0,67, 0,85, 2, 4 e 8,5 THz) foram projetados, fabricados e testados exibindo excepcional resposta. E finalmente um primeiro protótipo imageador foi montado acoplando os filtros de malha ressonante a câmera IV sem sua óptica original de germânio. As primeiras imagens THz de uma resistência aquecida é apresentada, provando a funcionalidade do conceito original. Os desenvolvimentos e estudos aqui apresentados estarão contribuindo para dois experimentos espaciais recentemente propostos, DESIR ( Detection of Solar eruptive Infrared Radiation) e SIRA (Submillimeter-wave to InfraRed solar Activity emissions), prevendo a utilização de sistemas THz em observações de transientes em plasmas ativos solares em diferentes freqüências, a partir do solo e no espaço / Abstract: This work presents important information on THz technology, currently considered a technological challenge and state of the art in different areas of development. To form a THz imaging system, still unavailable commercially, efforts in different fronts had been excused. Cameras for medium IR (8 - 14 µm) had been acquired, characterized and tested, with excellent and unknown results in Solar Physics, application considered for this work. Filters of resonant metal mesh for diverse bands in the THz region (centered in 0,4, 0,67, 0,85, 2, 4 and 8,5 THz) had been projected, manufactured and tested showing excellent results. Finally a first imaging system was mounted connecting the filters of resonant mesh to the IR camera without its original optics of germanium. The first THz images of a warm resistance are presented, proving the functionality of the original concept. The developments and studies presented here will contribute for two space experiments recently considered, DESIR ( Solar Detection of eruptive Infrared Radiation) and SIRA ( Submillimeter-wave you the solar InfraRed Activity emissions), requiring the use of THz systems for observations of transient in solar active plasmas in different frequencies, from the ground and in the space / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutor em Engenharia Elétrica
28

Contribution à l’étude des modifications hémodynamiques de la veine axillaire après curage axillaire. / Contribution to the study of the hemodynamic modification of the axillary vein after axillary lymph node dissection

Belgrado, Jean-Paul 25 April 2017 (has links)
Les lymphœdèmes secondaires au traitement du cancer du sein représentent une des comorbidités majeures de l’adénomectomie axillaire. L’exérèse des lymphonœuds axillaires est pointée comme la cause évidente de l’apparition du lymphœdème. Elle semble être une condition nécessaire, mais non suffisante, pour que les patientes développent un lymphœdème secondaire. Les patientes opérées selon la même procédure chirurgicale et affectées d’un lymphœdème secondaire peuvent être catégorisées en deux groupes :l’un présentant un œdème caractérisé par le signe du godet marqué et une réponse rapide aux bandages compressifs, l’autre montrant les signes inverses. Nous posons l’hypothèse que parmi les causes intercurrentes à la genèse du lymphœdème secondaire au traitement du cancer du sein, la procédure chirurgicale du creux axillaire peut induire des perturbations intermittentes de l’hémodynamique de la veine axillaire et provoquer une hyperfiltration d’amont. Notre travail montre que l’exérèse de tout ou partie de la lame cellulo-adipeuse qui contient les lymphonœuds et l’ouverture de la gaine axillaire, modifie les conditions biomécaniques de la veine axillaire, lorsque le bras est ballant le long du corps, ayant pour conséquence une occlusion partielle et intermittente de cette veine, ce qui détermine aux distalités du membre une augmentation de la filtration. Cette occlusion intermittente provoque un épaississement réactionnel local de l’endothélium veineux et induit à terme le développement d’un réseau veineux collatéral superficiel visible sur le thorax à l'aide de l'imagerie par thermographie à infrarouges lointains. Après avoir démontrer l’existence clinique de l'occlusion intermittente par différentes méthodes expérimentales et cliniques, nous avons proposer à la fois des moyens diagnostiques simples et initier une proposition de traitement chirurgical visant à rétablir de meilleures conditions hémodynamiques veineuses qui pourraient contribuer à la décongestion partielle du membre. / Doctorat en Sciences de la motricité / info:eu-repo/semantics/nonPublished
29

Rotation-vibration spectroscopic studies of formaldehyde and formic acid

Lohilahti, J. (Jarmo) 10 May 2006 (has links)
Abstract The thesis consists of seven studies dealing with high resolution vibration-rotation spectra of planar asymmetric tops. Six studies deal with D212CO and D213CO species of the formaldehyde molecule and one study is from DCOOH specie of the formic acid molecule. The measurements were carried out at high accuracy and the rotational analyses of the recorded spectra were performed. The observed anharmonic and Coriolis resonances were taking into account in the analyses. The rotational constants of the present and literature studies were used in evaluation of the planarity defects of formaldehyde and formic acid molecules in the summary part of the thesis. Finally, a semi-experimental structure for formaldehyde was obtained by employing experimental and theoretical data.
30

Multi-modal, Multi-Domain Pedestrian Detection and Classification : Proposals and Explorations in Visible over StereoVision, FIR and SWIR / Détection et classification de piétons multi-modale, multi-domaine : propositions et explorations dans visible sur stéréo vision, infrarouge lointain et infrarouge à ondes courtes

Miron, Alina Dana 16 July 2014 (has links)
L’intérêt principal des systèmes d’aide à la conduite (ADAS) est d’accroître la sécurité de tous les usagers de la route. Le domaine du véhicule intelligent porte une attention particulière au piéton,l’une des catégories la plus vulnérable. Bien que ce sujet ait été étudié pendant près de cinquante ans par des chercheurs, une solution parfaite n’existe pas encore. Nous avons exploré dans ce travail de thèse différents aspects de la détection et la classification du piéton. Plusieurs domaines du spectre (Visible, Infrarouge proche, Infrarouge lointain et stéréovision) ont été explorés et comparés.Parmi la multitude des systèmes imageurs existants, les capteurs infrarouge lointain (FIR),capables de capturer la température des différents objets, reste particulièrement intéressants pour la détection de piétons. Les piétons ont, le plus souvent, une température plus élevée que les autres objets. En raison du manque d’accessibilité publique aux bases de données d’images thermiques, nous avons acquis et annoté une base de donnée, nommé RIFIR, contenant à la fois des images dans le visible et dans l’infrarouge lointain. Cette base nous a permis de comparer les performances de plusieurs attributs présentés dans l’état de l’art dans les deux domaines.Nous avons proposé une méthode générant de nouvelles caractéristiques adaptées aux images FIR appelées « Intensity Self Similarity (ISS) ». Cette nouvelle représentation est basée sur la similarité relative des intensités entre différents sous-blocks dans la région d’intérêt contenant le piéton.Appliquée sur différentes bases de données, cette méthode a montré que, d’une manière générale,le spectre infrarouge donne de meilleures performances que le domaine du visible. Néanmoins, la fusion des deux domaines semble beaucoup plus intéressante.La deuxième modalité d’image à laquelle nous nous sommes intéressé est l’infrarouge très proche (SWIR, Short Wave InfraRed). Contrairement aux caméras FIR, les caméras SWIR sont capables de recevoir le signal même à travers le pare-brise d’un véhicule. Ce qui permet de les embarquer dans l’habitacle du véhicule. De plus, les imageurs SWIR ont la capacité de capturer une scène même à distance lointaine. Ce qui les rend plus appropriées aux applications liées au véhicule intelligent. Dans le cadre de cette thèse, nous avons acquis et annoté une base de données, nommé RISWIR, contenant des images dans le visible et dans le SWIR. Cette base a permis une comparaison entre différents algorithmes de détection et de classification de piétons et entre le visible et le SWIR. Nos expérimentations ont montré que les systèmes SWIR sont prometteurs pour les ADAS. Les performances de ces systèmes semblent meilleures que celles du domaine du visible.Malgré les performances des domaines FIR et SWIR, le domaine du visible reste le plus utilisé grâce à son bas coût. Les systèmes imageurs monoculaires classiques ont des difficultés à produire une détection et classification de piétons en temps réel. Pour cela, nous avons l’information profondeur (carte de disparité) obtenue par stéréovision afin de réduire l’espace d’hypothèses dans l’étape de classification. Par conséquent, une carte de disparité relativement correcte est indispensable pour mieux localiser le piéton. Dans ce contexte, une multitude de fonctions coût ont été proposées, robustes aux distorsions radiométriques, pour le calcul de la carte de disparité.La qualité de la carte de disparité, importante pour l’étape de classification, a été affinée par un post traitement approprié aux scènes routières.Les performances de différentes caractéristiques calculées pour différentes modalités (Intensité,profondeur, flot optique) et domaines (Visible et FIR) ont été étudiées. Les résultats ont montré que les systèmes les plus robustes sont ceux qui prennent en considération les trois modalités,plus particulièrement aux occultations. / The main purpose of constructing Intelligent Vehicles is to increase the safety for all traffic participants. The detection of pedestrians, as one of the most vulnerable category of road users, is paramount for any Advance Driver Assistance System (ADAS). Although this topic has been studied for almost fifty years, a perfect solution does not exist yet. This thesis focuses on several aspects regarding pedestrian classification and detection, and has the objective of exploring and comparing multiple light spectrums (Visible, ShortWave Infrared, Far Infrared) and modalities (Intensity, Depth by Stereo Vision, Motion).From the variety of images, the Far Infrared cameras (FIR), capable of measuring the temperature of the scene, are particular interesting for detecting pedestrians. These will usually have higher temperature than the surroundings. Due to the lack of suitable public datasets containing Thermal images, we have acquired and annotated a database, that we will name RIFIR, containing both Visible and Far-Infrared Images. This dataset has allowed us to compare the performance of different state of the art features in the two domains. Moreover, we have proposed a new feature adapted for FIR images, called Intensity Self Similarity (ISS). The ISS representation is based on the relative intensity similarity between different sub-blocks within a pedestrian region of interest. The experiments performed on different image sequences have showed that, in general, FIR spectrum has a better performance than the Visible domain. Nevertheless, the fusion of the two domains provides the best results. The second domain that we have studied is the Short Wave Infrared (SWIR), a light spectrum that was never used before for the task of pedestrian classification and detection. Unlike FIRcameras, SWIR cameras can image through the windshield, and thus be mounted in the vehicle’s cabin. In addition, SWIR imagers can have the ability to see clear at long distances, making it suitable for vehicle applications. We have acquired and annotated a database, that we will name RISWIR, containing both Visible and SWIR images. This dataset has allowed us to compare the performance of different pedestrian classification algorithms, along with a comparison between Visible and SWIR. Our tests have showed that SWIR might be promising for ADAS applications,performing better than the Visible domain on the considered dataset. Even if FIR and SWIR have provided promising results, Visible domain is still widely used due to the low cost of the cameras. The classical monocular imagers used for object detectionand classification can lead to a computational time well beyond real-time. Stereo Vision providesa way of reducing the hypothesis search space through the use of depth information contained in the disparity map. Therefore, a robust disparity map is essential in order to have good hypothesis over the location of pedestrians. In this context, in order to compute the disparity map, we haveproposed different cost functions robust to radiometric distortions. Moreover, we have showed that some simple post-processing techniques can have a great impact over the quality of the obtained depth images.The use of the disparity map is not strictly limited to the generation of hypothesis, and couldbe used for some feature computation by providing complementary information to color images.We have studied and compared the performance of features computed from different modalities(Intensity, Depth and Flow) and in two domains (Visible and FIR). The results have showed that the most robust systems are the ones that take into consideration all three modalities, especially when dealing with occlusions.

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