Segmentation d'Images Texturées Couleur à l'aide de modèles paramétriques pour approcher la distribution des erreurs de prédiction linéaires

International audienceWe propose novel a priori parametric models to approximate the distribution of the two dimensional multichannel linear prediction error in order to improve the performance of color texture segmentation algorithms. Two dimensional linear prediction models are used to characterize the spatial structures in color images. The multivariate linear prediction error of these texture models is approximated with Wishart distribution and multivariate Gaussian mixture models. A novel color texture segmentation framework based on these models and a spatial regularization model of initial class label fields is presented. For the proposed method and with different color spaces, experimental results show better performances in terms of percentage segmentation error, in comparison with the use of a multivariate Gaussian law.Nous présentons de nouveaux modèles paramétriques pour approcher la distribution des erreurs de prédiction linéaire issues d’un signal multicanal bidimensionnel. Ces modèles sont utilisés afin d’améliorer la performance d’algorithmes de segmentation d’images texturées couleur. Les modèles de prédiction linéaire 2D offrent une caractérisation des structures spatiales des textures couleur. Dans ce papier, la distribution de l’erreur de prédiction linéaire associée à ces modèles est approchée à l’aide de la distribution de Wishart et des lois de mélanges gaussiennes multidimensionnelles. La méthode de segmentation est basée sur ces modèles de distribution et un modèle de régularisation spatiale des régions. Les résultats montrent qu’en termes de pourcentage d’erreur de segmentation, les performances sont améliorées avec la méthode proposée pour les trois espaces couleur testés par rapport à l’utilisation d’une loi de gauss multidimensionnelle

Texture and Colour in Image Analysis

Research in colour and texture has experienced major changes in the last few years. This book presents some recent advances in the field, specifically in the theory and applications of colour texture analysis. This volume also features benchmarks, comparative evaluations and reviews

Segmentation d'images par combinaison adaptative couleur-texture et classification de pixels. (Applications à la caractérisation de l'environnement de réception de signaux GNSS)

En segmentation d images, les informations de couleur et de texture sont très utilisées. Le premier apport de cette thèse se situe au niveau de l utilisation conjointe de ces deux sources d informations. Nous proposons alors une méthode de combinaison couleur/texture, adaptative et non paramétrique, qui consiste à combiner un (ou plus) gradient couleur et un (ou plus) gradient texture pour ensuite générer un gradient structurel utilisé comme image de potentiel dans l algorithme de croissance de régions par LPE. L originalité de notre méthode réside dans l étude de la dispersion d un nuage de point 3D dans l espace, en utilisant une étude comparative des valeurs propres obtenues par une analyse des composantes principales de la matrice de covariance de ce nuage de points. L approche de combinaison couleur/texture proposée est d abord testée sur deux bases d images, à savoir la base générique d images couleur de BERKELEY et la base d images de texture VISTEX. Cette thèse s inscrivant dans le cadre des projets ViLoc (RFC) et CAPLOC (PREDIT), le deuxième apport de celle-ci se situe au niveau de la caractérisation de l environnement de réception des signaux GNSS pour améliorer le calcul de la position d un mobile en milieu urbain. Dans ce cadre, nous proposons d exclure certains satellites (NLOS dont les signaux sont reçus par réflexion voir totalement bloqués par les obstacles environnants) dans le calcul de la position d un mobile. Deux approches de caractérisation, basées sur le traitement d images, sont alors proposées. La première approche consiste à appliquer la méthode de combinaison couleur/texture proposée sur deux bases d images réelles acquises en mobilité, à l aide d une caméra fisheye installée sur le toit du véhicule de laboratoire, suivie d une classification binaire permettant d obtenir les deux classes d intérêt ciel (signaux LOS) et non ciel (signaux NLOS). Afin de satisfaire la contrainte temps réel exigée par le projet CAPLOC, nous avons proposé une deuxième approche basée sur une simplification de l image couplée à une classification pixellaire adaptée. Le principe d exclusion des satellites NLOS permet d améliorer la précision de la position estimée, mais uniquement lorsque les satellites LOS (dont les signaux sont reçus de manière direct) sont géométriquement bien distribués dans l espace. Dans le but de prendre en compte cette connaissance relative à la distribution des satellites, et par conséquent, améliorer la précision de localisation, nous avons proposé une nouvelle stratégie pour l estimation de position, basée sur l exclusion des satellites NLOS (identifiés par le traitement d images), conditionnée par l information DOP, contenue dans les trames GPS.Color and texture are two main information used in image segmentation. The first contribution of this thesis focuses on the joint use of color and texture information by developing a robust and non parametric method combining color and texture gradients. The proposed color/texture combination allows defining a structural gradient that is used as potential image in watershed algorithm. The originality of the proposed method consists in studying a 3D points cloud generated by color and texture descriptors, followed by an eigenvalue analysis. The color/texture combination method is firstly tested and compared with well known methods in the literature, using two databases (generic BERKELEY database of color images and the VISTEX database of texture images). The applied part of the thesis is within ViLoc project (funded by RFC regional council) and CAPLOC project (funded by PREDIT). In this framework, the second contribution of the thesis concerns the characterization of the environment of GNSS signals reception. In this part, we aim to improve estimated position of a mobile in urban environment by excluding NLOS satellites (for which the signal is masked or received after reflections on obstacles surrounding the antenna environment). For that, we propose two approaches to characterize the environment of GNSS signals reception using image processing. The first one consists in applying the proposed color/texture combination on images acquired in mobility with a fisheye camera located on the roof of a vehicle and oriented toward the sky. The segmentation step is followed by a binary classification to extract two classes sky (LOS signals) and not sky (NLOS signals). The second approach is proposed in order to satisfy the real-time constraint required by the application. This approach is based on image simplification and adaptive pixel classification. The NLOS satellites exclusion principle is interesting, in terms of improving precision of position, when the LOS satellites (for which the signals are received directly) are well geometrically distributed in space. To take into account the knowledge of satellite distribution and then increase the precision of position, we propose a new strategy of position estimation, based on the exclusion of NLOS satellites (identified by the image processing step), conditioned by DOP information, which is provided by GPS data.BELFORT-UTBM-SEVENANS (900942101) / SudocSudocFranceF

From Dome to Disease: The Respiratory Toxicity of Volcanic Cristobalite

Exposure to fine-grained volcanic ash can potentially cause acute and chronic respiratory disease. The toxicity of ash is likely to vary depending on the type and style of eruption; eruptions at dome-forming volcanoes, in particular, can produce ash containing substantial quantities of respirable crystalline silica, a recognised human carcinogen and causative agent of silicosis. Volcanic domes crystallise crystalline silica as cristobalite, which is metastable at dome-forming temperatures (ca. 850 °C), through deposition from silica-saturated vapours and through devitrification of volcanic glass. Five dome-forming volcanoes are studied to constrain the hazard posed by volcanic cristobalite, including: Colima, Mexico; Merapi, Indonesia; Mount St. Helens, USA; Santiaguito, Guatemala; and Unzen, Japan. The evolution of the cristobalite hazard is investigated from crystallisation in volcanic settings to its potential effect on biological systems, through a series of petrological, physicochemical and toxicological studies. We rationalise the presence of metastable cristobalite below its stability field in all domes studied by way of a textural investigation, and conclude that the incorporation of aluminium and sodium into the silica structure facilitates crystallisation. Since particle toxicology is dependent on composition and structure, the observation of cation substitutions is expanded in a geochemical and thermodynamic investigation of volcanic cristobalite to constrain its mineralogy. We find that incorporation of 1-4 wt. % aluminium leads to a poorly-ordered cristobalite structure. This investigation facilitates a mineralogical comparison of the cristobalite hazard among volcanic locations and provides the framework for assessing volcanic cristobalite toxicity. We investigate the ability of volcanic ash to elicit an in vitro pro-inflammatory response, focusing on silica-mediated experiments, and relate the influence of structure and composition to the potential physiological burden. We find that volcanic cristobalite can be mineralogically considered as a single entity among locations, and that cristobalite-bearing ash is less toxic than expected. Nonetheless, we recommend that eruptions be considered on a case-by-case basis to most effectively aid the risk mitigation work of disaster managers globally

Revisiting the art of Francis Bacon and his contemporaries

The nine items that I am submitting for a PhD by publication (two books and seven articles, amounting to some 220,000 words in total) constitute, I claim, a coherent body of research in terms of both subject-matter and of underlying art-historical methodology. The field studied is British figurative painting during the 1940s and 1950s, with particular reference to the art of Francis Bacon, who emerged as an innovative and influential figure at that time. Other British artists under scrutiny include Graham Sutherland, Lucian Freud and Frank Auerbach. My main interest is in visual intelligence and the process of visual translation within creativity, as discussed in the accompanying, 12,000 word reflective essay. I seek to analyse how artists feed in a highly purposeful and inventive manner off one another (Bacon and Sutherland in the 1940s), off their predecessors (such as Edgar Degas, Waiter Sickert, Chaim Soutine, Pablo Picasso and Alberto Giacometti) and, especially in the case of Bacon, off various kinds of photographic imagery, above all propaganda emanating from pre-war Nazi Germany. This approach serves to embed the interpretation of meaning and content, a crucial concern for all these artists against the backdrop of a profoundly traumatic period in world history, within the analysis of formal language and of the process whereby artists and extend and manipulate to their own ends available resources of two-dimensional imagery

Application of Physics-Based Image Formation Models to Change Detection in The Context of Indoor Workplace Video Surveillance

The aim of this thesis is to investigate the application of physics-based image formation models to change detection in the context of indoor workplace video surveillance. First, video surveillance applications are reviewed. Based on this review, a new classification of video surveillance applications is proposed and indoor workplace surveillance is chosen as the target application. A new workplace surveillance modelis then introduced, which relates the needs of workplace surveillance applications, their implications and the capabilities of video surveillance techniques. Furthermore, a set of requirements for workplace surveillance applications are elicited and a videobased workplace system structure is proposed. Change detection is then reviewed, and the suitability of using physics-based image formation models to enhance change detection algorithms is investigated. Two physics-based change detection techniques are developed. The foundations of these techniques are advances of colour constancy techniques which extract physical features from the camera output; this approach is unlike other change detection algorithms which use the camera output directly without considering its physical meaning. The performance of the proposed techniques is measured and compared against the Horprasert algorithm, using objective and computational complexity evaluation methods, where the quality of the change detection is measured using recall and precision measures. The Horprasert algorithm was shown, in an independent study by other researchers, to have the best trade-off between segmentation quality and computational complexity among other state-of-the-art algorithms such as Cavallaro, McKenna and Shen under experimental conditions which covered different lightings and background structures

Liver Biopsy

Liver biopsy is recommended as the gold standard method to determine diagnosis, fibrosis staging, prognosis and therapeutic indications in patients with chronic liver disease. However, liver biopsy is an invasive procedure with a risk of complications which can be serious. This book provides the management of the complications in liver biopsy. Additionally, this book provides also the references for the new technology of liver biopsy including the non-invasive elastography, imaging methods and blood panels which could be the alternatives to liver biopsy. The non-invasive methods, especially the elastography, which is the new procedure in hot topics, which were frequently reported in these years. In this book, the professionals of elastography show the mechanism, availability and how to use this technology in a clinical field of elastography. The comprehension of elastography could be a great help for better dealing and for understanding of liver biopsy

7th International Conference on Higher Education Advances (HEAd'21)

Information and communication technologies together with new teaching paradigms are reshaping the learning environment.The International Conference on Higher Education Advances (HEAd) aims to become a forum for researchers and practitioners to exchange ideas, experiences,opinions and research results relating to the preparation of students and the organization of educational systems.Doménech I De Soria, J.; Merello Giménez, P.; Poza Plaza, EDL. (2021). 7th International Conference on Higher Education Advances (HEAd'21). Editorial Universitat Politècnica de València. https://doi.org/10.4995/HEAD21.2021.13621EDITORIA

Spatial Structure Characterization Of Textures In IHLS Colour Space

International audienc

Mechanical weathering in cold regions with special emphasis on the Antarctic environment and the freeze-thaw mechanism in particular.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.Consideration of almost any geomorphology textbook will show the fundamental argument that in cold environments mechanical weathering processes, usually freeze-thaw, will predominate and that chemical weathering will be temperature-limited, often to the point of non occurrence. These basic concepts have underpinned geomorphology for over a century and are the basis for the development of many landforms in periglacial regions. With the introduction of data loggers so field data became more readily available but, sadly, those data were not of a quality to other than justify the existent assumptions and thus did little more than reinforce, rather than test, the nature of our understanding of cold region weathering. Factors such as rock properties were dealt with to a limited extent but rock moisture was all but ignored, despite its centrality to most weathering processes. Here the results of field studies into weathering in cold regions, coupled with laboratory experiments based on the field data, are presented. An attempt is made to overcome the shortcomings of earlier studies. Temperature, moisture and rock properties have all been considered. Processes were not assumed but rather the data were used to evaluate what processes were operative. The results, both in terms of weathering process understanding per se and of its application to landform development, significantly challenge our longheld perceptions. Information is presented that shows that it is not temperature, but rather water, that is the limiting factor in cold region weathering. Indeed, in the absence of water, many cold environments have attributes akin to a hot desert. The relevance of this is that weathering processes other than freeze-thaw may play a significant role and that in the presence of water chemical weathering can play a far greater role than hitherto thought. Overall, the whole concept of zonality with respect to weathering is questioned. Finally, the attributes of weathering are put within the context of landform development and questions raised regarding the origin of some forms and of their palaeoenvironmental significance. Attributes of periglacial, glacial and zoogeomorphic processes and landforms in present and past cold environments are also presented