Dissertations / Theses on the topic 'Détection du volume du couvert'
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Mohammadi, Vahid. "Design, Development and Evaluation of a System for the Detection of Aerial Parts and Measurement of Growth Indices of Bell Pepper Plant Based on Stereo and Multispectral Imaging." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2022. http://www.theses.fr/2022UBFCK109.
Full textDuring the growth of plants, monitoring them brings much benefits to the producers. This monitoring includes the measurement of physical properties, counting plants leaves, detection of plants and separation of them from weeds. All these can be done different techniques, however, the techniques are favorable that are non-destructive because plant is a very sensitive creature that any manipulation can put disorder in its growth or lead to losing leaves or branches. Imaging techniques are of the best solutions for plants growth monitoring and geometric measurements. In this regard, in this project the use of stereo imaging and multispectral data was studied. Active and passive stereo imaging were employed for the estimation of physical properties and counting leaves and multispectral data was utilized for the separation of crop and weed. Bell pepper plant was used for imaging measurements for a period of 30 days and for crop/weed separation, the spectral responses of bell pepper and five weeds were measured. Nine physical properties of pepper leaves (i.e. main leaf diameters, leaf area, leaf perimeter etc.) were measured using a scanner and was used as a database and also for comparing the estimated values to the actual values. The stereo system consisted of two LogiTech cameras and a video projector. First the stereo system was calibrated using sample images of a standard checkerboard in different position and angles. The system was controlled using the computer for turning a light line on, recording videos of both cameras while light is being swept on the plant and then stopping the light. The frames were extracted and processed. The processing algorithm first filtered the images for removing noise and then thresholded the unwanted pixels of environment. Then, using the peak detection method of Center of Mass the main and central part of the light line was extracted. After, the images were rectified by using the calibration information. Then the correspondent pixels were detected and used for the 3D model development. The obtained point cloud was transformed to a meshed surface and used for physical properties measurement. Passive stereo imaging was used for leaf detection and counting. For passive stereo matching six different matching algorithms and three cost functions were used and compared. For spectral responses of plants, they were freshly moved to the laboratory, leaves were detached from the plants and placed on a blur dark background. Type A lights were used for illumination and the spectral measurements were carried out using a spectroradiometer from 380 nm to 1000 nm. To reduce the dimensionality of the data, PCA and wavelet transform were used. Results of this study showed that the use of stereo imaging can propose a cheap and non-destructive tool for agriculture. An important advantage of active stereo imaging is that it is light-independent and can be used during the night. However, the use of active stereo for the primary stage of growth provides acceptable results but after that stage, the system will be unable to detect and reconstruct all leaves and plant's parts. Using ASI the R2 values of 0.978 and 0.967 were obtained for the estimation leaf area and perimeter, respectively. The results of separation of crop and weeds using spectral data were very promising and the classifier—which was based on deep learning—could completely separate pepper from other five weeds
Brigui, Frédéric. "Algorithmes d'imagerie SAR polarimétriques basés sur des modèles à sous-espace : application à la détection de cible sous couvert forestier." Paris 10, 2010. http://www.theses.fr/2010PA100171.
Full textThis thesis deals with the development of new SAR processors for detection of targats under foliage. For this application, classical SAR images are very noisy; the target has a low response and there are a lot of false alarms due to the interferences which are mainly the trunks of the forest. To detect target and reduce interferences, we reconsider the way processing a SAR image by using models which take into account the scattering properties of the target and the interferences. These models are developed for signals in sigle polarisation and in double polarisation (HH and VV) and are defined with low-rank subspaces generated from the responses of canonical elements. From this modeling, we develop new SAR processors. First, we focus on the detection of the target and on the reduction of false alarms. The performances of these processors in terms of detection and false alarms reduction are evaluated with realistic simulated data and we emphasize on the interest of using a polimetric information. We also apply these algorithms to real data that allows us to analyze the images in real-life context
Hettak, Lydia. "Mise en œuvre d'un modèle électromagnétique 3D dédié à l'analyse de milieux forestiers et à la détection de cibles sous couvert." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066415/document.
Full textIn this report, a model for the analysis of the scattering of metallic target placed in forested area is presented. The developed model is based on a hybrid (surface/volume) formulation of the method of moments. First, a model based on the surface formulation of the electric field integral equation is developed for the case of a metallic target placed in free space. The model is then modified in order to take into account the presence of a ground by using a complex image method coupled with the Fresnel reflection coefficients. Finally, the obtained code is coupled with a model treating the case of large forest areas that was previously developed in the laboratory. This model is based on a volume formulation of the electric field integral equation coupled with the Characteristics Basis Functions Method. The final hybrid model treats the case of metallic object placed in a large forested area. The model is then implemented on MATLAB and Fortran in order to compare its results with those of the commercial software FEKO. The results were compared different cases: free space, above ground and inside a forested area. The code was also used in order to different parameters affecting the diffraction mechanism. Finally, a numerical validation conducted in collaboration with CCRM (Centre Commun de Ressources en Micro-ondes de Marseille) is presented. A measurement complain of the diffracted field was achieve on scaled models (1/25) and the measurements were compared with the results given by the developed model
San, Emeterio Cabañes José Luis. "Désertification ou reverdissement ? Etude multiscalaire de l'évolution du couvert végétal en Afrique Sahélienne à partir de données de télédétection." Sorbonne Paris Cité, 2015. http://www.theses.fr/2015USPCC079.
Full textThe Sahel region has become the archetype of desertification and land degradation since the important droughts that took place during the 70s and 80s. However, the rainfall recovery since the middle of the 90s and the re-greening trend observed from remoting sensed vegetation indexes has challenged the view of an advancing desertification in the Sahel. Nevertheless, the relation between these indexes and land degradation is very complex and the conclusions made are sometimes contradictory. In fact, the high climate variability and the important landscape mutations, due to demographic growth, make of land degradation assessment a difficult task in this region. The strong interdependency between temporal and spatial scales of land degradation, led to carry out a multi-scalar analysis to understand; what is the actual situation of the Sahel concerning land degradation, and what is the most effective way to assess this phenomenon at a regional scale. This analysis has been done for the entire Sahel region during the period 1982-2011using the NDVI GIMMS-3g vegetation index and rainfall products. It has been later transposed to south-west Niger using the NDVI MODIS index and aerial and satellite photographs of the last decades
Rabus, David. "Résonateur à ondes élastiques de volume à harmoniques élevés (HBARs) pour mesures gravimétriques : application à la détection de gaz." Phd thesis, Université de Franche-Comté, 2013. http://tel.archives-ouvertes.fr/tel-00923625.
Full textRabus, David. "Résonateurs à ondes élastiques de volume à modes harmoniques élevés (HBARs) pour mesures gravimétriques : application à la détection de gaz." Thesis, Besançon, 2013. http://www.theses.fr/2013BESA2038/document.
Full textThe demand for compact and autonomous systems devoted to field detection of gaseous compounds is still persisting in arapidly changing international context (food-processing, sustainable development, security, and so on). The thesis reportedin this manuscript, supported by the Délégation Générale de l’Armement, develops new resonant sensor solutions basedon high overtone bulk acoustic waves (so-called HBARs) for chemical compound detection and more specifically explosivesubstances. These high compactness resonators are built using a transducer bound or deposited onto a resonant cavity,yielding a comb spectrum modulating its own frequency response. They are used generally as dipoles, but a quadrupolestructure allowing for transverse mode coupling has been particularly used for our developments. A theoretical study ofthe behaviour of these devices based on lithium niobate-on-quartz or qluminum nitride-on-silicon material stack has beenachieved to determine the gravimetric properties of these configurations accounting for their mode specificities. Variouscalibration techniques have been implemented to confirm the theoretical analysis and to define the most appropriate structurefor a given application. The produced results have been compared to those of a quartz guided-wave micro-balance toemphasize the strength (compactness, reduced chemical kinetics, multiphysics measurements) and weakness (gravimetricsensitivity requiring device thickness less than 100 μm) of our devices. An embedded signal processing electronics alsohas been developed to treat the information provided by our sensors, offering fast or accurate (millidegree range) detectionprotocols. The dedicated electronics aims at providing the flexibility needed to track multiple modes at variaous fixed frquencieswhile getting rid of the long sweep time of general purpose network analyzers. A eight-channel version of thissystem has been set to process several sensor in parallel or to monitor several modes of two HBAR sensors for effectivemuti-physics measurements in a reduced analysis domain (a few cubic mm). Phase noise is the limiting factor determiningthe detection limit. The system has been deployed for gas detection as well as for monitoring other physical parameters suchas temperature or viscosity under various experimental condition including fluid media
Bienaimé, Alex. "Microcapteur en arséniure de gallium pour la détection de molécules dans un fluide." Thesis, Besançon, 2012. http://www.theses.fr/2012BESA2025/document.
Full textThe biomarkers detection for screening, diagnosis or treatment of disease requires the development of highly sensitive devices combining low cost of analysis, a small size and quick responses. In this context, we develop a biosensor using bulk acoustic wave to allow the detection of specific analyte in a complex biological medium. The geometry used is a piezoelectric resonant membrane using shear mode vibration excited by lateral field. The transducer uses the specific properties of gallium arsenide to provide a highly sensitive and selective detection thanks to its piezoelectric properties and also its microfabrication or biofonctionnalisation facilities. First, we dimensioned the device and modeled it behavior. A sensitivity to adding mass has been estimated at 0.1 ng.Hz-1. Then, we considered the sensor microfabrication using only low cost process (photolithography and wet etching). Through these processes, we obtained well formed thick membranes (50μm) with specific surface properties and microstructuration. Next, we realize the biointerface through the development of a specific chemical interface in order to immobilize a dense protein monolayer covalently attached to the GaAs surface. This monolayer was characterized by an original analysis coupling the atomic force microscopy and the mass spectroscopy MALDI-TOF. Finally, fluid and electrical interfaces have been developed and we tested the device by impedance measurements
Bachelier, Elodie. "Modélisation électromagnétique des effets de diffusion de surface et de volume des sols par la méthode des différences finies." Toulouse, ENSAE, 1999. http://www.theses.fr/1999ESAE0017.
Full textLi, Gengxiang. "Rehaussement et détection des attributs sismiques 3D par techniques avancées d'analyse d'images." Phd thesis, Université Michel de Montaigne - Bordeaux III, 2012. http://tel.archives-ouvertes.fr/tel-00731886.
Full textLacour, Vivien. "Optimisation d'un microcapteur GaAs à ondes acoustiques et de sa biointerface pour la détection de pathogènes en milieu liquide." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/10471.
Full textAbstract : This PhD thesis was realized in the context of a cotutelle program between FEMTO-ST institute in France and the University of Sherbrooke in Canada. The thesis addresses the development of a potentially low cost sensor dedicated for detection of pathogens in food industry processing, environment and biosafety sectors. Such a sensor could serve detection of Escherichia coli bacteria whose pathogenic strains are the source of foodborne illnesses encountered worldwide every year. Hence, biosensor devices are needed for a rapid, sensitive and selective detection of pathogens to avert, as soon as possible, any sources of contamination and prevent outbreak risks. The design of the sensor consists of a resonant membrane fabricated in gallium arsenide (GaAs) crystal that operates at shear modes of bulk acoustic waves generated by lateral field excitation. In addition to the attractive piezoelectric properties, as shown in this work, fabrication of a GaAs-based biosensor benefits from a well-developed technology of microfabrication of GaAs, as well as biofunctionalization and the possibility of regeneration that should result in cost savings of used devices. The transducer element was fabricated by using typical clean room microfabrication techniques. Plasma and wet etching were investigated and compared for achieving thin membranes with high quality surface morphology. At the same time, we designed and fabricated fluidic elements that allowed the construction of a flow cell chamber integrated in the sensor. Extensive research was carried out with a Fourier transform infrared spectroscopy (FTIR) diagnostic tool to determine optimum conditions for biofunctionalization of the GaAs surface. This activity allowed to advance the fundamental knowledge of self-assembly formation and, consequently, fabrication of high density biointerfaces for efficient immobilization of selected bioreceptors. Among different biochip regeneration methods, it has been demonstrated that liquid UV photooxidation (liquid-UVPO) has a great potential to deliver attractive surfaces for re-usable biochips. Finally, operation of the transducer device was evaluated in air environment and in various liquid media, simulating real conditions for detection.
Emteu, Tchagou Serge Vladimir. "Réduction à la volée du volume des traces d'exécution pour l'analyse d'applications multimédia de systèmes embarqués." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAM051/document.
Full textThe consumer electronics market is dominated by embedded systems due to their ever-increasing processing power and the large number of functionnalities they offer.To provide such features, architectures of embedded systems have increased in complexity: they rely on several heterogeneous processing units, and allow concurrent tasks execution.This complexity degrades the programmability of embedded system architectures and makes application execution difficult to understand on such systems.The most used approach for analyzing application execution on embedded systems consists in capturing execution traces (event sequences, such as system call invocations or context switch, generated during application execution).This approach is used in application testing, debugging or profiling.However in some use cases, execution traces generated can be very large, up to several hundreds of gigabytes.For example endurance tests, which are tests consisting in tracing execution of an application on an embedded system during long periods, from several hours to several days.Current tools and methods for analyzing execution traces are not designed to handle such amounts of data.We propose an approach for monitoring an application execution by analyzing traces on the fly in order to reduce the volume of recorded trace.Our approach is based on features of multimedia applications which contribute the most to the success of popular devices such as set-top boxes or smartphones.This approach consists in identifying automatically the suspicious periods of an application execution in order to record only the parts of traces which correspond to these periods.The proposed approach consists of two steps: a learning step which discovers regular behaviors of an application from its execution trace, and an anomaly detection step which identifies behaviors deviating from the regular ones.The many experiments, performed on synthetic and real-life datasets, show that our approach reduces the trace size by an order of magnitude while maintaining a good performance in detecting suspicious behaviors
Timofeeva, Maria. "Sonde magnétique inductive de haute sensibilité et conditionneur adapté très faible impédance : Perspectives de détection mixte Electrique : Magnétique, sans contact, à haute sensibilité, pour impédance-métrie résolue en volume." Caen, 2012. http://www.theses.fr/2012CAEN2049.
Full textThis PhD thesis was carried out in the framework of a contract CIFRE between the GREYC laboratory and the company Inphynix. The objective is the study and development of high performance magnetometers, based on search coils and associated transimpedance amplifier with a perspective of simultaneous measurement of both Electric E and Magnetic H fields. The magnetometer specifications were a high bandwidth, a high dynamic range and a small volume occupancy. A theoretical and experimental study of compact search coils dedicated were performed. The spatial resolution for search coils with different geometrical forms was studied. Differential current amplifiers and transimpedance amplifiers optimized for this application were studied especially for differential signal mode transfer and noise. An original differential search coil based magnetometer, made of coupled coils, operating in flux mode and connected to a differential transimpedance amplifier has been developed. It was shown that this structure is better than two separated coils in terms of volume occupancy, spatial resolution, noise and low cut-off frequency. The structure of an original mixed E-H field sensor and its amplifier has been defined. Key words: Search coil sensor, Magnetometer, Transimpedance amplifier, Differentiel current amplifier, Spatial resolution, mixed E-H field sensor
Himmelstein, Jesse Cooper. "Geometric operators for motion planning." Toulouse, INSA, 2008. http://eprint.insa-toulouse.fr/archive/00000241/.
Full textLa planification du mouvement connait une utilisation croissante dans le contexte industriel. Qu’elle soit destinée à la programmation des robots dans l’usine ou au calcul de l’assemblage d’une pièce mécanique, la planification au travers des algorithmes probabilistes est particulièrement efficace pour résoudre des problèmes complexes et difficiles pour l’opérateur humain. Cette thèse CIFRE, effectuée en collaboration entre le laboratoire de recherche LAAS-CNRS et la jeune entreprise Kineo CAM, s’attache à résoudre la problématique de planification de mouvement dans l’usine numérique. Nous avons identifié trois domaines auxquels s’intéressent les partenaires industriels et nous apportons des contributions dans chacun d’eux: la détection de collision, le volume balayé et le mouvement en collision. La détection de collision est un opérateur critique pour analyser des maquettes numériques. Les algorithmes de planification de mouvement font si souvent appel à cet opérateur qu’il représente un point critique pour les performances. C’est pourquoi, il existe une grande variété d’algorithmes spécialisés pour chaque type de géométries possibles. Cette diversité de solutions induit une difficulté pour l’intégration de plusieurs types de géométries dans la même architecture. Nous proposons une structure algorithmique rassemblant des types géométriques hétérogènes pour effectuer les tests de proximité entre eux. Cette architecture distingue un noyau algorithmique commun entre des approches de division de l’espace, et des tests spécialisés pour un couple de primitives géométriques donné. Nous offrons ainsi la possibilité de facilement ajouter des types de données nouveaux sans pénaliser la performance. Notre approche est validée sur un cas de robot humanoïde qui navigue dans un environnement inconnu grâce à la vision. Concernant le volume balayé, il est utilisé pour visualiser l’étendue d’un mouvement, qu’il soit la vibration d’un moteur ou le geste d‘un mannequin virtuel. L’approche la plus innovante de la littérature repose sur la puissance du matériel graphique pour calculer une approximation du volume balayé très rapidement. Elle est toutefois limitée en entrée à un seul objet, qui luimême doit décrire un volume fermé. Afin d’adapter cet algorithme au contexte de la conception numérique, nous modifions son comportement pour traiter des « soupes de polygones » ainsi que des trajectoires discontinues. Nous montrons son efficacité sur les mouvements de désassemblage pour des pièces avec un grand nombre de polygones. Il est difficile de manipuler le volume décrit par une soupe de polygones. A partir du calcul du volume balayé, nous introduisons des opérateurs qui changent la taille de l’objet discret. Ces operateurs calculent la somme de Minkowski entre l’objet et une sphère afin d’agrandir l’objet, et la différence de Minkowski pour le rétrécir. Nous obtenons les résultats sur les objets statiques ainsi que dynamiques. Enfin, nous abordons le problème de la planification de mouvement en collision. Cette antilogie exprime la capacité d’autoriser une collision bornée pendant la recherche de trajectoire. Ceci permet de résoudre certains problèmes d’assemblage très difficiles. Par exemple, lors du calcul des séquences de désassemblage, il peut être utile de permettre à des « pièces obstacles » telles que les vis de se déplacer pendant la planification. De plus, en autorisant la collision, nous sommes capables de résoudre des problèmes de passage en force. Cette problématique se pose souvent dans la maquette numérique où certaines pièces sont « souples » ou si le problème consiste à identifier la trajectoire « la moins pire » quand aucun chemin sans collision n’existe. Nous apportons dans ce travail plusieurs contributions qui s’appliquent à la conception numérique pour la robotique industrielle. Nous essayons de marier une approche scientifique avec des critères de fonctionnalités strictes pour mieux s’adapter aux utilisateurs de la conception numérique. Nous cherchons à exposer les avantages et les inconvénients de nos approches tout au long du manuscrit
Himmelstein, Jesse. "Geometric operators for motion planning." Phd thesis, INSA de Toulouse, 2008. http://tel.archives-ouvertes.fr/tel-00348010.
Full textHandouzi, Wahida. "Traitement d'information mono-source pour la validation objective d'un modèle d'anxiété : application au signal de pression sanguine volumique." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0237/document.
Full textDetection and evaluation of emotions are areas of great interest in many communities both in terms of human and exact sciences. In this thesis we focus on social anxiety recognition, which is an irrational fear felt by a person during any form of social relationship. Anxiety can be revealed by a set of physical and physiological traits such as tone of voice, facial expressions, increased heart rate, flushing ... etc. The interest to the physiological measures is motivated by them robustness to avoid the artifacts created by human social masking, they are a continuous source of data and each emotion is characterized by a particular physiological variation. In this work, we propose a measurement system based on the use of a single physiological signal "Blood volume pulse BVP". The use of a single sensor limits the subjects’ discomfort. From the BVP signal we selected three relevant features which best represents the close relationship between this signal and anxiety status. This features set is classified using support vector machine SVM. The work undertaken in the field of emotion recognition frequently use, for information support, unreliable data do not always correspond to the situations envisaged. This lack of reliability may be due to several parameters among them the subjectivity of the evaluation method used (self-evaluation questionnaire, subjects…etc.). We have developed an approach to objective assessment of data based on the dynamics of selected features. The used database was recorded in our laboratory under real conditions acquired in subjects with a level of anxiety during social situations and who are not under psychological treatment. The used stimulus is the exposition to virtual environments representing some feared social situations. After the evaluation stage, we obtained a reliable model for the recognition of two levels of anxiety. The latter was tested in a clinic specializing in cognitive behavioral therapy (CBT) on phobic subjects. The results highlight the reliability of the built model specifically for the recognition of anxiety levels in healthy subjects or of phobic subjects, what constitutes a solution to the lack of data affecting different areas of recognition
Ramah, Houerbi Khadija. "Mesures et Caractérisation du Trafic dans le Réseau National Universitaire (RNU)." Phd thesis, 2009. http://tel.archives-ouvertes.fr/tel-00656376.
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