111 research outputs found

    Colour image enhancement by virtual histogram approach

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    Airborne laser scanning raster data visualization

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    This guide provides an insight into a range of visualization techniques for high-resolution digital elevation models (DEMs). It is provided in the context of investigation and interpretation of various types of historical and modern, cultural and natural small-scale relief features and landscape structures. It also provides concise guidance for selecting the best techniques when looking at a specific type of landscape and/or looking for particular kinds of forms.The three main sections – descriptions of visualization techniques, guidance for selection of the techniques, and visualization tools – accompany examples of visualizations, exemplar archaeological and geomorphological case studies, a glossary of terms, and a list of references and recommendations for further reading. The structure facilitates people of different academic background and level of expertise to understand different visualizations, how to read them, how to manipulate the settings in a calculation, and choose the best suited for the purpose of the intended investigation.A smaller amount of books is also available in hardcover (ISBN 978-961-05-0011-7, 24 EUR).Monografija nudi vpogled v nabor tehnik prikaza visokoločljivih modelov višin. Napisana je v kontekstu preučevanja in interpretacije različnih tipov zgodovinskih in modernih, kulturnih in naravnih majhnih reliefnih oblik. Daje jedrnate napotke za izbiro najboljših tehnik prikaza določenih tipov pokrajine in izrazitih oblik.Tri glavna poglavja – opis tehnik prikazovanja digitalnih modelov višin, napotki za njihovo izbiro in orodja za izračun prikazov –, spremljajo izbrani primeri tipičnih arheoloških in geomorfoloških študij, slovarček pojmov ter seznam literature in priporočenega branja. Posameznikom z različnih znanstvenih področij in z različnim predznanjem o tematiki je struktura v pomoč pri razumevanju različnih tehnik prikazov, kako jih brati, kako izbrati prave nastavitve pri njihovem izračunu in kako prepoznati najbolj primerne za namen zasnovane raziskave

    Unsupervised methods for large-scale, cell-resolution neural data analysis

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    In order to keep up with the volume of data, as well as the complexity of experiments and models in modern neuroscience, we need scalable and principled analytic programmes that take into account the scientific goals and the challenges of biological experiments. This work focuses on algorithms that tackle problems throughout the whole data analysis process. I first investigate how to best transform two-photon calcium imaging microscopy recordings – sets of contiguous images – into an easier-to-analyse matrix containing time courses of individual neurons. For this I first estimate how the true fluorescence signal gets transformed by tissue artefacts and the microscope setup, by learning the parameters of a realistic physical model from recorded data. Next, I describe how individual neural cell bodies may be segmented from the images, based on a cost function tailored to neural characteristics. Finally, I describe an interpretable non-linear dynamical model of neural population activity, which provides immediate scientific insight into complex system behaviour, and may spawn a new way of investigating stochastic non-linear dynamical systems. I hope the algorithms described here will not only be integrated into analytic pipelines of neural recordings, but also point out that algorithmic design should be informed by communication with the broader community, understanding and tackling the challenges inherent in experimental biological science

    Computer-assisted detection of lung cancer nudules in medical chest X-rays

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    Diagnostic medicine was revolutionized in 1895 with Rontgen's discovery of x-rays. X-ray photography has played a very prominent role in diagnostics of all kinds since then and continues to do so. It is true that more sophisticated and successful medical imaging systems are available. These include Magnetic Resonance Imaging (MRI), Computerized Tomography (CT) and Positron Emission Tomography (PET). However, the hardware instalment and operation costs of these systems remain considerably higher than x-ray systems. Conventional x-ray photography also has the advantage of producing an image in significantly less time than MRI, CT and PET. X-ray photography is still used extensively, especially in third world countries. The routine diagnostic tool for chest complaints is the x-ray. Lung cancer may be diagnosed by the identification of a lung cancer nodule in a chest x-ray. The cure of lung cancer depends upon detection and diagnosis at an early stage. Presently the five-year survival rate of lung cancer patients is approximately 10%. If lung cancer can be detected when the tumour is still small and localized, the five-year survival rate increases to about 40%. However, currently only 20% of lung cancer cases are diagnosed at this early stage. Giger et al wrote that "detection and diagnosis of cancerous lung nodules in chest radiographs are among the most important and difficult tasks performed by radiologists"

    The GE.N.ESIS Project - Georeferenced Depiction and Synthesis of Marine Archaeological Survey Data in Greece

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    Through the GE.N.ESIS project, the Hellenic Ephorate of Underwater Antiquities (EUA) is introduced to a digital tool for visualisation and synthesis of underwater archaeological data. A marine geoarchaeological survey was conducted at the Methoni underwater archaeological site (Greece) in the summer of 2012 utilising geophysical instruments. The acquired data together with archival archaeological data was managed through a Geographical Information System (GIS). The survey results present the ruins of a submerged prehistoric settlement, the Methoni ancient harbour and submerged breakwater, wrecks, cannons and artefacts/features – all of which are of potential archaeological interest. The project outcomes provide the genesis of a new baseline capability for the cultural management of the Greek archaeological sites.Gracias al Proyecto GE.N.ESIS, le ha sido presentada al “Hellenic Ephorate of Underwater Antiquities” (EUA) una herramienta digital para la visualización y la síntesis de datos arqueológicos submarinos. Un levantamiento geoarqueológico marino fue efectuado en el sitio arqueológico submarino de Methoni (Grecia) durante el verano del 2012, utilizando instrumentos geofísicos. Los datos adquiridos, junto con los datos de los archivos arqueológicos, fueron administrados a través del Sistema de Información Geográfica (SIG). Los resultados del levantamiento presentan las ruinas de un emplaza-miento prehistórico sumergido, el antiguo Puerto de Methoni y el rompeolas sumergido, restos de naufragios, cañones y artefactos/objetos, todos ellos de un interés arqueológi-co potencial. El resultado del proyecto proporciona la génesis de una nueva capacidad de referencia para la gestión cultural de los sitios arqueológicos griegos.Dans le cadre du projet GE.N.ESIS, l’éphorat grec des antiquités sous-marines (EUA) est présenté via un outil numérique de visualisation et de synthèse des données archéologi-ques sous-marines. Un levé géo-archéologique marin a été réalisé sur le site d’archéolo-gie marine de Méthone (Grèce) au cours de l’été 2012 à l’aide d’instruments de géophysique. Les données acquises ainsi que les données archéologiques d’archives ont été gérées via un système d’information géographique (SIG). Les résultats du levé présentent les ruines d’une zone de peuplement préhistorique submergée, l’ancien port de Méthone et des brise-lames, épaves, canons et artefacts/éléments submergés – tous d’intérêt archéologique potentiel. Les résultats du projet fournissent la génèse d’une nouvelle capacité de base pour la gestion culturelle des sites archéologiques grecs

    Feasibility of seismic monitoring methods for Australian CO2 storage projects

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    I study the detectability of CO2 plumes by seismic methods for three Australian Carbon Capture and Storage projects. I quantify the ability of CO2 plume detection for different acquisition designs applicable to the projects. I evaluate both pre- and post-stack seismic imaging methods. Any detectability study depends on a realistic model of noise. For both of the imaging methods I design a different approach to model the time-lapse noise needed to evaluate the detectability

    The evaluation of Corona and Ikonos satellite imagery for archaeological applications in a semi-arid environment

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    Archaeologists have been aware of the potential of satellite imagery as a tool almost since the first Earth remote sensing satellite. Initially sensors such as Landsat had a ground resolution which was too coarse for thorough archaeological prospection although the imagery was used for geo-archaeological and enviro-archaeological analyses. In the intervening years the spatial and spectral resolution of these sensing devices has improved. In recent years two important occurrences enhanced the archaeological applicability of imagery from satellite platforms: The declassification of high resolution photography by the American and Russian governments and the deregulation of commercial remote sensing systems allowing the collection of sub metre resolution imagery. This thesis aims to evaluate the archaeological application of three potentially important resources; Corona space photography and Ikonos panchromatic and multispectral imager). These resources are evaluated in conjunction with Landsat Thematic Mapper (TM) imagery over a 600 square km study area in the semi-arid environment around Homs, Syria. The archaeological resource in this area is poorly understood, mapped and documented. The images are evaluated for their ability to create thematic layers and to locate archaeological residues in different environmental zones. Further consideration is given to the physical factors that allow archaeological residues to be identified and how satellite imagery and modern technology may impact on Cultural Resource Management. This research demonstrates that modern high resolution and historic satellite imagery can be important tools for archaeologists studying in semi-arid environments. The imagery has allowed a representative range of archaeological features and landscape themes to be identified. The research shows that the use of satellite imagery can have significant impact on the design of the archaeological survey in the middle-east and perhaps in other environments
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