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Extraire des mesures sur des surfaces est un problème dans de nombreux domaines de recherche. L'archaïsme de certains systèmes ou la cherté d'appareils perfectionnés empêchent l'extraction rapide et robuste de ces paramètres. Pourtant, ils sont essentiels dans de nombreux domaines, comme les paramètres de rugosité qui interviennent dans de nombreux phénomènes physiques ou les valeurs dendrométriques pour l'étude de la bio-diversité. En parallèle, l'utilisation et la production de contenus 3D se développent considérablement ces dernières années dans des domaines très divers. Le but de cette thèse est donc d'utiliser toutes ces innovations dans le domaine de la reconstruction 3D et de les appliquer à la mesure de paramètres de surfaces. Pour cela, il est nécessaire de créer une chaîne complète de reconstruction 3D, n'utilisant que des images prises sans contrainte dans le but d'être accessible au plus grand nombre. Dans cette chaîne nous utilisons des algorithmes de stéréo-vision robustes produisant, pour chaque couple d'images, un nuage de points. Après le passage de ces nuages dans un référentiel commun, une étape de filtrage des points 3D et de suppression des redondances est nécessaire. Une étape de lissage permet d'obtenir le nuage final. Pour justifier des bons résultats obtenus, une étape de validation nous a permis de vérifier et d'étudier la robustesse de la chaîne de traitements développée. Enfin, les paramètres de rugosités et dendrométriques seront extraits. Nous étudierons dans ces deux cas, comment extraire ces informations et leurs utilisations / Extracting measures on surfaces is a problem in many areas of research. The archaism of some systems or the costliness of sophisticated devices prevent the fast and robust extraction of these parameters. Yet these measures are essential in many areas, such as roughness parameters involved in many physical phenomena or dendrometric values for the study of biodiversity. In parallel, the use and production of 3D content has grown dramatically this past year in very diverse domains. The purpose of this thesis is to use these innovations in the context of surfaces parameter measurements. It is necessary to create a complete chain of 3D reconstruction, using pictures taken without constraint, in order to be open to as many people. This chain uses robust stereo-vision algorithms in order to produce a point cloud for each pair of images. After the generation of these point cloud in the same geometric frame, a filtering step of 3D points and a deletion step of redundancies are necessary and a smoothing step allows us to obtain the final point cloud. To reveal the good results, a validation step has enabled us to verify and investigate the robustness of the developed chain. The roughness and dendrometric parameters are finally extracted. We will study in both cases, how to extract this information and their uses

COSTA, Roner Ferreira da. Estudo de sensibilidade do modelo Brams variáveis dos parâmetros de superfície do Nordeste do Brasil. 2007. 76 f. Dissertação (Mestrado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2007. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-05-29T22:10:07Z No. of bitstreams: 1 2007_dis_rfcosta.pdf: 970792 bytes, checksum: cb8cda8b3f31847a5d98d052c2c5ac87 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-05-29T22:17:57Z (GMT) No. of bitstreams: 1 2007_dis_rfcosta.pdf: 970792 bytes, checksum: cb8cda8b3f31847a5d98d052c2c5ac87 (MD5) / Made available in DSpace on 2015-05-29T22:17:57Z (GMT). No. of bitstreams: 1 2007_dis_rfcosta.pdf: 970792 bytes, checksum: cb8cda8b3f31847a5d98d052c2c5ac87 (MD5) Previous issue date: 2007 / In this work a numeric experiment was accomplished with the model BRAMS (Brazilian Regional Atmospheric Modeling System) with the purpose of studying the changes in the surface variables due to the variations of the surface parameters as soil moisture and the vegetation class in the Northeast of Brazil which are input in BRAMS. They were made three simulations, the first (simulation control) it was initialized with the standard files of the own model, the second simulation was maintained the class of vegetation pattern (Deciduous shrub) and just altering the soil moisture and the third simulation alters the vegetation for semi-desert besides reducing the humidity of the soil. Also a validation of the model was accomplished with a soil humidity made calculations starting from observed data of precipitation. It is verified that the humidity of the soil and the vegetation have a strong influences on the climate of the Northeast area of Brazil; however it is not very significant in the weather forecast. / Neste trabalho foi realizado um experimento numérico com o modelo BRAMS (Brazilian Regional Atmospheric Modeling System) com a finalidade de estudar as mudanças verificadas nas variáveis de superfície devido às variações dos parâmetros de superfície tais como, umidade do solo e a classe de vegetação no Nordeste do Brasil que alimentam o BRAMS. Foram feitas três simulações, a primeira (simulação controle) foi inicializadas com os arquivos padrões do próprio modelo, a segunda simulação foi mantido a classe de vegetação padrão (Deciduous shrub) alterando apenas a umidade do solo e a terceira simulação altera a vegetação para semi-deserto além de reduzir a umidade do solo. Também foi realizada uma validação do modelo com uma umidade de solo calculada a partir de dados observados de precipitação. Verifica-se que a umidade do solo e a vegetação têm uma forte influência sobre o clima da região Nordeste do Brasil, porém não é muito significativa na previsão do tempo.

The ability of fast and accurate acquiring of large 3D spatial data is the main benefit for consideration of a terrestrial laser scanner in deformation monitoring. The objective of this paper is to discuss this technique with support of practical experiments performed inside a laboratory. It also includes measuring changes from millimetre to sub millimetre level and a comparison of measurements from a terrestrial laser scanner with measurements of other instruments. Various areas of applications are reviewed. The report discusses a surface modeling method to estimate deformation parameters of objects, such as planar, spherical and cylindrical surface representations. Illustrative numerical examples are performed by simulating randomly generated sample point coordinates for estimation of changes of modeled planar and cylindrical surfaces. The practical experiments were performed using a scan of a carton box, a ball and a rounded paper holder, which correspond to the planar, spherical and cylindrical surfaces, respectively. Independent measurements were performed using a total station and a measuring tape to make a comparison with the scanner measurements. A statistical test was performed independently for the changes obtained from each type of modeled surface in order to check whether the movement is real or due to measurement noises.  A significant change of the normal of a plane was detected between epochs, and similar results were obtained from both scanner and total station measurements. The normal of the plane was rotated by  between scan epochs. A translation of 3.2 and 3.7 millimetres were detected between scan epochs for the center of the sphere and axis of the cylinder, respectively. Only the scanner data was used in this case. From the scanner measurement changes in radii of the sphere and the cylinder were obtained as 1.6 and 3.1 millimetres, respectively between scan epochs. The measurement of the scanner was verified by performing independent measurements using measuring tape. And hence the change in radii of the sphere and the cylinder were obtained as 2.5 and 4 millimetres, respectively.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho foi realizado um experimento numÃrico com o modelo BRAMS (Brazilian Regional Atmospheric Modeling System) com a finalidade de estudar as mudanÃas verificadas nas variÃveis de superfÃcie devido Ãs variaÃÃes dos parÃmetros de superfÃcie tais como, umidade do solo e a classe de vegetaÃÃo no Nordeste do Brasil que alimentam o BRAMS. Foram feitas trÃs simulaÃÃes, a primeira (simulaÃÃo controle) foi inicializadas com os arquivos padrÃes do prÃprio modelo, a segunda simulaÃÃo foi mantido a classe de vegetaÃÃo padrÃo (Deciduous shrub) alterando apenas a umidade do solo e a terceira simulaÃÃo altera a vegetaÃÃo para semi-deserto alÃm de reduzir a umidade do solo. TambÃm foi realizada uma validaÃÃo do modelo com uma umidade de solo calculada a partir de dados observados de precipitaÃÃo. Verifica-se que a umidade do solo e a vegetaÃÃo tÃm uma forte influÃncia sobre o clima da regiÃo Nordeste do Brasil, porÃm nÃo à muito significativa na previsÃo do tempo. / In this work a numeric experiment was accomplished with the model BRAMS (Brazilian Regional Atmospheric Modeling System) with the purpose of studying the changes in the surface variables due to the variations of the surface parameters as soil moisture and the vegetation class in the Northeast of Brazil which are input in BRAMS. They were made three simulations, the first (simulation control) it was initialized with the standard files of the own model, the second simulation was maintained the class of vegetation pattern (Deciduous shrub) and just altering the soil moisture and the third simulation alters the vegetation for semi-desert besides reducing the humidity of the soil. Also a validation of the model was accomplished with a soil humidity made calculations starting from observed data of precipitation. It is verified that the humidity of the soil and the vegetation have a strong influences on the climate of the Northeast area of Brazil; however it is not very significant in the weather forecast.

La forêt Pyrénéenne comporte une grande richesse en bois dont la qualité est encore très peu étudiée. Une valorisation de ces ressources locales constitue un des enjeux de la filière forêt-bois dans la région afin d'apporter plus de valeur ajoutée et d'accroître les bénéfices de cette filière. C'est dans ce contexte que cette thèse a vu le jour pour découvrir la potentialité des ressources locales et pour comparer leur performance (hêtre des Pyrénées, Douglas et Chêne). A l'heure actuelle, la majorité des entreprises s'imposent une sur-qualité pour améliorer la qualité de surface du bois usiné avant le collage ou avant l'application de la finition. A l'état actuel des connaissances, aucune étude n'a permis de répondre de façon précise à la question suivante : " quelles caractéristiques de l'état de surface donnent une performance acceptable à la finition et au collage ? ". L'objectif principal de ma thèse est donc d'identifier des critères quantitatifs permettant de caractériser l'état de surface du bois usiné en vue d'évaluer sa performance vis-à-vis d'une application donnée, et d'en déduire les conditions de coupe optimales. Deux domaines d'application ont été étudiés : le collage du bois en construction et en menuiserie intérieure, la finition du bois en menuiserie intérieure. Pour mener à bien ces travaux, de nombreux essais ont été réalisés: (i) Usinage du bois chez les industriels en faisant varier les paramètres de rabotage et de ponçage pour obtenir toutes les gammes possibles de qualités de surface et de performances; (ii) Caractérisation des états de surfaces usinées (mesures des paramètres topographiques 3D, des paramètres physico-chimiques et des endommagements anatomiques); (iii) Collage et application de la finition chez les industriels; (iv) Evaluation de la performance au collage (performance à l'adhésion et durabilité du collage), et de la performance à la finition (performance esthétique par analyse des relevés de fibres qui apparaissent après l'application d'un vernis aqueux, la performance à l'adhésion et la durabilité de la finition). Au final, les caractéristiques géométriques, physico-chimiques et anatomiques essentielles que doit avoir une surface usinée pour assurer une performance au collage et à la finition acceptable et durable ont été identifiées. Une modélisation des relations entre les paramètres d'état de surface et les critères de performance pour chaque application a été établie. Les résultats découlant de cette recherche constituent une référence pour les travaux futurs sur la fonctionnalité des surfaces bois usinées. En effet, les modèles établis s'avèrent d'une importance capitale, d'une part pour optimiser l'usinage du bois dans le contexte industriel, et d'autre part pour simuler la performance d'une surface donnée en fonction de ses caractéristiques. En outre, l'étude a permis d'évaluer la performance des ressources locales (hêtre des Pyrénées) par rapport aux essences communément utilisées (chêne et douglas). La thèse présente donc des intérêts multiples dans le développement de la connaissance scientifique et de l'économie régionale. / The Pyrenees forest has significant old-growth but non-valued timber resources. One of the current challenges consists in using those forest resources to generate better added-value and enhance the benefits for the regional wood industry. It was in this context, that this thesis started to discover the potentiality of local resources, and to compare their performance (Pyrenees beech, Douglas fir and Oak). Most wood industries impose an over-quality to improve the surface due to a lack of knowledge on the surface characteristics that would optimize bonding and finishing. To date, no previous scientific research has examined what surfaces characteristics give an acceptable bonding and finishing performance. This study mainly aims to identify quantitative criteria which characterize wood machined surface to evaluate the performance for a given application. Two areas of application were studied: wood bonding for structural and non-structural uses, wood finishing for interior joinery. Several tests were performed to reach the goal: (i) Wood machining processes were carried out using industry machines. The levels of planning and sanding parameters were varied to obtain all possible ranges of surface quality and performances; (ii) Wood machined surfaces were characterized (measurement of 3D topographic surface parameters, physico-chemical parameters and anatomical defects); (iii) Bonding and finishing application were performed in industry; (iv) Bonding performance (adhesion performance, durability), and finishing performance (esthetical performance by analyzing the raised fibers due to the application of waterborne varnish, adhesion performance and durability) were assessed. The essential geometric characteristics required for a machined surface to ensure acceptable bonding and finishing performance were identified. Models that link surface parameters and performance criteria for each application were established. This study represents an essential reference for future research works on the functionality of machined wood surfaces. Indeed, the established models are of paramount importance, on one hand to optimize the cutting of woods in industry, and on the other hand to simulate the performance of a given surface depending on its characteristics. In addition, this study assessed how performant local resources (Pyrenees beech) are relative to other commonly used wood species (Oak and Douglas). Therefore, this PhD thesis has multiple interests in the advancement of scientific knowledge and the development of regional economy.

The main theme of this thesis is the surface topography evaluation. The theoretical part introduces the fundamental methods of evaluation, measuring instruments and describes profile and surface topographic parameters. In the practical part, the influence of different cutting conditions in high-feed face milling was researched on sample made of aluminium alloy 7475-T7351. For the surface topography evaluation of all samples the measuring device Alicona IF G5 was used. The last part of the diploma thesis is devoted to the economic influence of cutting conditions on the process of high-feed face milling.

L'extraction des paramètres de surface est une activité essentielle des Sciences de la vie et de la Terre. Ce mémoire propose une nouvelle méthodologie pour l'analyse des paramètres biophysiques et géophysiques, appelée Réalité Terrain Étendue, et qui mêle les avantages des relevés terrain et de la télédétection. Nous nous sommes en particulier attachés aux avantages de la télédétection basse altitude et d'un système micro-drone multi-caméras pour la cartographie de la dynamique de la végétation à l'échelle des individus. Cette problématique pose de nombreuses contraintes sur notre système car l'identification des arbrisseaux nécessite des capteurs innovants et une adaptation aux cycles phénologiques pour améliorer leur capacité de discrimination. La télédétection basse altitude semble être une solution intéressante en terme de résolution spatiale et de souplesse opérationnelle, et le développement des micro-drones civils permet des outils d'autant plus performants et fiables pour les missions terrain. Nous avons donc mis en place un système complet de drone avec une charge utile spécifique emportant simultanément trois appareils photographiques pour l'acquisition à la demande d'images obliques, stéréoscopiques ou multispectrales et permettant le développement de nouvelles méthodes d'identification de la végétation. Enfin, en participant à un relevé terrain du Muséum national d'Histoire naturelle, nous avons validé l'intérêt de notre système pour la cartographie de la dynamique de la végétation. Ce travail s'ouvre sur de nombreuses applications et perspectives de recherche, comme l'extraction de paramètres biophysiques par stéréo-restitution et l'agriculture de précision / Retrieval of land surface parameters is an essential part of life and Earth sciences activities, as they are the key to understand the complex phenomena that take place in the biosphere. This thesis proposes a new methodology for biophysical and geophysical surface para-meters analysis, that we call Extended Ground Truth, and that mix the advantages of the field ope-rations and those of remote sensing. We have especially focused our work on the benefits of low altitude remote sensing with a multi-cameras Unmanned Aerial System for vegetation dynamics mapping at subject scale. This problematic raises strong constraints on the system, as the identification of small bushes implies new type of sensors and the adaptation to the phenological cycles to improve the discrimination capacity of the sensors. Low altitude remote sensing seems a good solution in terms of resolution and operational flexibility and the technical revolution behind the spreading of civilian micro-UAV allows all the more capable and reliable tools for field operations. We therefore developed an Unmanned Aerial System with a specific payload that can lift up three digital cameras at once, allowing on demand oblique, stereoscopic or multispectral synchronous acquisitions and thus the development of new identification methods of the vegetation. Finally, we have participated in a field operation on a test site of the National Natural History Museum and confirmed the interest of our tool for vegetation dynamics mapping. This work leads to many other researches, per example in the field of biophysical parameters extraction from stereoscopic images, and other application fields like precision farming

Made available in DSpace on 2015-03-26T13:32:15Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1445397 bytes, checksum: 2e00a708ce4685a98f700f3d00d17d31 (MD5) Previous issue date: 2012-02-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The present work had the purpose of evaluating the performance of the rotational central composite design (RCCD) in relation to the estimated response surface parameters, under conditions of simulated experimental errors that provide high coefficients of variation. The big impulse of the response methodology was given by Box and Wilson (1951), who developed methods of process optimization in industrial researches. Within these methods, the RCCD may be mentioned as an economic design for the response surface, due to the reduced number of level combinations in the studied factors, when compared to the full factorial. However, it is known that these designs are efficient where experimental mistakes are usually small and the conditions of the experiment are easily controlled. However, given the reduced number of tests by the RCCD, it has become important to verify its potential in designing treatments to adjust response surfaces on experiments related to agrarian sciences, that present, naturally, larger random error. For such, the treatment designs, full factorial and rotational central composite have been used to plan the combinations between the coded levels of two factors (A and B). A second-order model has been established for two factors A and B without interaction among them, named true response surface. A full 5x5 factorial has been established, with the combinations between the coded levels of factors A and B and 40 repetitions per treatment. In total, 1000 experimental units have been built. Afterwards, 100 simulations have been made for the experimental errors ε present in the experiment under normal conditions with average zero and variations σε2. The parameter σε has been specified in 32, 48, 64 and 80, to provide the residual coefficients of variation (CV) equal to 25, 37, 50 and 60 %. The choice of these coefficients of variation has been made in order to include the classifications created by Ferreira (1991), quoted by Silva et al. (2011), and Pimentel Gomes (1985) for the agrarian areas. The observed values of Y have been obtained from the sum of the true values of Y ( ) obtained from the true response surface, with residuals ( ), generated by the simulation. In each type of design (RCCD and full factorial), three, six, nine and twelve repetitions per treatment have been established. According to the combinations between the types of treatment, coefficients of variation and number of repetitions per treatment, 100 adjustments of the response surface have been realized, from which the averages of the coefficient of determination, the average distances between the true and the estimated critical point (CPD) and between the coefficients of variation estimated and simulated (CVD), besides the success percentage and confidence interval of each parameter and the percentage of success from the response surface. Afterwards, a regression of these measures as been made, evaluated based on the design, coefficient of variation and number of repetitions per treatment. The superiority of performance of the full factorial in relation to the RCCD increase in relation to the increase of the CV and the reducing of the number of repetitions per treatment. The RCCD has been recommended under more controlled experimental conditions, for being a more economic treatment design. However, knowing the difficulty of controlling the random error on experiments for the agrarian areas, in experiments of this nature the full factorial or the RCCD were recommended with a larger number of repetitions per treatment. It has also been concluded that the increase of the CV prejudices the adjustment quality of the full factorial and mainly of the RCCD and this prejudice can be compensated with the increase in the number of repetitions per treatment. It has been seen that the adjustment quality provided by the treatment design does not depend only of their quantity, but mostly on the sufficient amount of experimental units to provide proper estimates of the effects of the known and unknown factors. / Esse trabalho teve como objetivo avaliar o desempenho do delineamento composto central rotacional (DCCR) em relação às estimativas dos parâmetros da superfície de resposta estimada, sob condições de erros experimentais simulados que proporcionam altos coeficientes de variação. O grande impulso da metodologia de resposta foi dado por Box e Wilson (1951), que desenvolveram métodos de otimização de processos em pesquisas industriais. Dentre esses métodos, pode-se citar o DCCR como um delineamento econômico para a superfície de resposta, devido ao número reduzido de combinações entre os níveis dos fatores estudados, quando comparado ao fatorial completo. No entanto, sabe-se que estes delineamentos são eficientes onde normalmente os erros experimentais são pequenos e as condições do experimento são mais facilmente controláveis. Portanto, dada a economia do número de ensaios pelo DCCR, tornou-se importante verificar o seu potencial em delinear tratamentos visando o ajuste de superfícies de respostas para experimentos ligados às ciências agrárias, que apresentam, naturalmente, maiores erros aleatórios. Para tanto, os delineamentos de tratamentos, fatorial completo e composto central rotacional foram utilizados para planejar as combinações entre os níveis codificados de dois fatores (A e B). Foi estabelecido um modelo de segunda ordem para dois fatores A e B sem interação entre eles, denominada de superfície de resposta verdadeira. Foi estabelecido um fatorial completo 5x5, com as combinações entre os níveis codificados dos fatores A e B e com 40 repetições por tratamento. No total, foram constituídas 1000 unidades experimentais. Posteriormente, foram feitas 100 simulações para os erros experimentais presentes no experimento sob distribuição normal com média zero e variância σε2. O parâmetro σε foi especificado em 32, 48, 64 e 80, para fornecer os coeficientes de variação residuais (CV) iguais a 25, 37, 50 e 62 %. A escolha de tais coeficientes de variação foi feita de modo a abranger as classificações criadas por Ferreira (1991), citado por Silva et al. (2011), e Pimentel Gomes (1985) para as áreas agrárias. Os valores observados de Y foram obtidos a partir da soma dos valores verdadeiros de Y ( ) obtidos a partir da superfície de resposta verdadeira, com os resíduos , gerados pela simulação. Em cada tipo de delineamento (DCCR e fatorial completo), foram estabelecidas três, seis, nove e doze repetições por tratamento. De acordo com as combinações entre os tipos de delineamentos, coeficientes de variação e número de repetições por tratamento, foram realizados 100 ajustes da superfície de resposta dos quais foram obtidas as médias do coeficiente de determinação, EQM, a distância média entre o ponto crítico verdadeiro e o estimado (DPC) e a diferença média entre os coeficientes de variação estimados e simulados (DCV), além da porcentagem de acerto e intervalo de confiança de cada parâmetro e a porcentagem de acerto da superfície de resposta. Posteriormente foi feita uma regressão dessas medidas avaliadas em função do delineamento, coeficiente de variação e número de repetições por tratamento. A superioridade do desempenho do fatorial completo em relação DCCR aumentou em função do aumento do CV e da diminuição do número de repetições por tratamento. Recomendou-se o DCCR sob condições experimentais mais bem controladas, por ser um delineamento de tratamento mais econômico. No entanto, sabendo do difícil controle do erro aleatório em experimentos das áreas agrárias, em experimentos dessa natureza recomendou-se o fatorial completo ou o DCCR com um número maior de repetições por tratamento. Conclui-se também que o aumento do CV prejudica a qualidade de ajuste do fatorial completo e principalmente a do DCCR e esse prejuízo pode ser compensado com o aumento do número de repetições por tratamento. Percebeu-se que a qualidade de ajuste proporcionada pelo delineamento de tratamento não depende só da quantidade dos mesmos, mas principalmente da quantidade de unidades experimentais suficientes para proporcionar estimativas adequadas dos efeitos dos fatores conhecidos e desconhecidos.

Les espaces intertidaux correspondent à des estrans soumis à un régime de marée montrant un certain marnage. Il s’agit d’étendues basses constituées d’alluvions récentes, situées à proximité des mers à marée et envahies par les eaux lors des marées hautes. Les espaces intertidaux au nord du Vietnam sont sous l’influence de la mousson associé à un régime de marée diurne. Ils s’étendent sur environ 350 km le long de la côte. Le sud de la zone d’étude est marqué par le delta du fleuve Rouge et le fleuve Thai Binh qui apportent une grande quantité de sédiments, entraînant des estrans à dominante vaseuse ou vaso-silteuse. Le centre de la zone d’étude est caractérisé par des estrans noirs. L’exploitation du charbon dans la région de Cam Pha et de Ha Long expliquent un apport énorme de particules carbonées qui créent des estrans vaseux noirs tout à fait originaux. Cependant, les espaces intertidaux de ce secteur n’ont jusqu’à présent pas fait l’objet d’une étude détaillée. La présente thèse a pour objectif de répondre à quatre questions concernant ces espaces intertidaux :1. Comment la morphologie des estrans a-t-elle évolué depuis les 25 dernières années ?2. Quels sont les sédiments constituant ces estrans : granulométrie, teneur en carbonates, teneur en matière organique, etc. ?3. Quels sont les paramètres biophysiques de surface des estrans ?4. Quels sont les facteurs qui influencent les changements de morphologie des estrans et comment ces derniers peuvent-ils évoluer ?Afin de répondre à ces différentes questions, des images de télédétection tant optiques (Landsat, Spot, Aster, etc.) que radar (Sentinel-1A) ont été utilisées. Les analyses spatiales ont été réalisées à l’aide d’un système d’information géographique (SIG).Le présent travail est une thèse financée dans le cadre du programme liant l’Université de Sciences et Technologies de Hanoï et l’Université de Reims - Champagne-Ardenne, membre du consortium USTH. / Tidal flat is a special environment suffering tidal regime in which tidal flats are submerged during flood tide and exposing the air during ebb tide. Tidal flats in the north coast in Vietnam are constituted in diurnal tide condition with tide range varying from 0.3m to 3.5m. Along 350km coastline of the study area, the diversity of constituent conditions formed various tidal flats with different characteristic. Tidal flats in the southern part of the study area are fed by sediment from two large river systems, in the middle part forms the coal tidal flats, but the only sandy sediment along with tide domination constitute the large tidal flats in the north coast of the study area. This study apply remote sensing techniques and GIS tools to solve four scientific issues including: the evolution of tidal flats over periods from 1989 to 2014, the characteristics of sediments in tidal flats, the surface parameter of tidal flats, and the forcing factors which influence the future change of tidal flats. The results of the study shows that, tidal flats in the north coast in the study area are dramatically eroded but the tidal flats in the south coast are deposition by the concentration of fine sediments. In total 14 forcing factors, the coastal nature factor has highest forcing to the deposition of tidal flats. However, the factors of wind-wave effect and tidal flat width have negative influence to deposition. Consequently, the highest potential for future deposition of tidal flats are around the river mouths in the south coast but no potential for future deposition is in tidal flats in the north of the study area. This study is implemented in the framework of the cooperation between University of Science and Technology Ha Noi (USTH) and Université de Reims Champagne-Ardenne (URCA).