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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

Computational models of primary visual cortex and the structure of natural images

Bartsch, Hauke. Unknown Date (has links) (PDF)
Techn. University, Diss., 2003--Berlin.
22

Quantitative petrographic investigations of porphyritic rhyolitic laccoliths of the Halle Volcanic Complex, Germany

Mock, Alexander 13 July 2009 (has links) (PDF)
Felsic phenocrysts of the laccoliths have straight size distributions (characteristic lengths 3.4 to 36 mm) and R-values from 1.34 to 0.78 (randomly distributed, no touching frameworks). Laccoliths have crystallinities from 10 to 30%. Textural coarsening possibly played a role in crystallization history. Serial sectioning reveals true shapes, sizes and three dimensional size distributions, non-touching frameworks, aspect ratios from 1.7:1.5:1 to 8.7:1.9:1 and a minimum sampling size of ~200 crystals. Different textural varieties develop late in system evolution and differed in density (~1%), viscosity and, thus, level of emplacement. Phenocryst populations formed on a timescale between 10 days and 2000 years, growth during emplacement is negligible. Models for filling and cooling of laccoliths suggest timescales from few 100 to ~20000 years. Contacts of laccoliths appear brecciated and sometimes show intercalation of magma and host sediment under ductile deformation. Dimensions of laccoliths plot in the field for such intrusions on a logarithmic width vs. thickness plot. Laccoliths intruded as distinct magma batches. More laccoliths than recognised before can be distinguished. Comparing felsic laccolith complexes in Late Palaeozoic transtensional basins, gives rise to new types of laccolith complexes termed Donnersberg and Halle type.
23

Quantitative petrographic investigations of porphyritic rhyolitic laccoliths of the Halle Volcanic Complex, Germany

Mock, Alexander 02 July 2004 (has links)
Felsic phenocrysts of the laccoliths have straight size distributions (characteristic lengths 3.4 to 36 mm) and R-values from 1.34 to 0.78 (randomly distributed, no touching frameworks). Laccoliths have crystallinities from 10 to 30%. Textural coarsening possibly played a role in crystallization history. Serial sectioning reveals true shapes, sizes and three dimensional size distributions, non-touching frameworks, aspect ratios from 1.7:1.5:1 to 8.7:1.9:1 and a minimum sampling size of ~200 crystals. Different textural varieties develop late in system evolution and differed in density (~1%), viscosity and, thus, level of emplacement. Phenocryst populations formed on a timescale between 10 days and 2000 years, growth during emplacement is negligible. Models for filling and cooling of laccoliths suggest timescales from few 100 to ~20000 years. Contacts of laccoliths appear brecciated and sometimes show intercalation of magma and host sediment under ductile deformation. Dimensions of laccoliths plot in the field for such intrusions on a logarithmic width vs. thickness plot. Laccoliths intruded as distinct magma batches. More laccoliths than recognised before can be distinguished. Comparing felsic laccolith complexes in Late Palaeozoic transtensional basins, gives rise to new types of laccolith complexes termed Donnersberg and Halle type.
24

Algorithmen der Bildanalyse und -synthese für große Bilder und Hologramme / Algorithms for image analysis and synthesis of large images and holograms

Kienel, Enrico 22 February 2013 (has links) (PDF)
Die vorliegende Arbeit befasst sich mit Algorithmen aus dem Bereich der Bildsegmentierung sowie der Datensynthese für das so genannte Hologrammdruck-Prinzip. Angelehnt an ein anatomisch motiviertes Forschungsprojekt werden aktive Konturen zur halbautomatischen Segmentierung digitalisierter histologischer Schnitte herangezogen. Die besondere Herausforderung liegt dabei in der Entwicklung von verschiedenen Ansätzen, die der Anpassung des Verfahrens für sehr große Bilder dienen, welche in diesem Kontext eine Größe von einigen hundert Megapixel erreichen können. Unter dem Aspekt der größtmöglichen Effizienz, jedoch mit der Beschränkung auf die Verwendung von Consumer-Hardware, werden Ideen vorgestellt, welche eine auf aktiven Konturen basierende Segmentierung bei derartigen Bildgrößen erstmals ermöglichen sowie zur Beschleunigung und Reduktion des Speicheraufwandes beitragen. Darüber hinaus wurde das Verfahren um ein intuitives Werkzeug erweitert, das eine interaktive lokale Korrektur der finalen Kontur gestattet und damit die Praxistauglichkeit der Methode maßgeblich erhöht. Der zweite Teil der Arbeit beschäftigt sich mit einem Druckprinzip für die Herstellung von Hologrammen, basierend auf virtuellen Abbildungsgegenständen. Der Hologrammdruck, der namentlich an die Arbeitsweise eines Tintenstrahldruckers erinnern soll, benötigt dazu spezielle diskrete Bilddaten, die als Elementarhologramme bezeichnet werden. Diese tragen die visuelle Information verschiedener Blickrichtungen durch einen festen geometrischen Ort auf der Hologrammebene. Ein vollständiges, aus vielen Elementarhologrammen zusammengesetztes Hologramm erzeugt dabei ein erhebliches Datenvolumen, das parameterabhängig schnell im Terabyte-Bereich liegen kann. Zwei unabhängige Algorithmen zur Erzeugung geeignet aufbereiteter Daten unter intensiver Ausnutzung von Standard-Graphikhardware werden präsentiert, hinsichtlich ihrer Berechnungs- sowie Speicherkomplexität verglichen und unter Berücksichtigung von Qualitätsaspekten bewertet.
25

Geographic object-based image analysis

Marpu, Prashanth Reddy 27 July 2009 (has links) (PDF)
The field of earth observation (EO) has seen tremendous development over recent time owing to the increasing quality of the sensor technology and the increasing number of operational satellites launched by several space organizations and companies around the world. Traditionally, the satellite data is analyzed by only considering the spectral characteristics measured at a pixel. The spatial relations and context were often ignored. With the advent of very high resolution satellite sensors providing a spatial resolution of ≤ 5m, the shortfalls of traditional pixel-based image processing techniques became evident. The need to identify new methods then led to focusing on the so called object-based image analysis (OBIA) methodologies. Unlike the pixel-based methods, the object-based methods which are based on segmenting the image into homogeneous regions use the shape, texture and context associated with the patterns thus providing an improved basis for image analysis. The remote sensing data normally has to be processed in a different way to that of the other types of images. In the geographic sense OBIA is referred to as Geographic Object-Based Image Analysis (GEOBIA), where the GEO pseudo prefix emphasizes the geographic components. This thesis will provide an overview of the principles of GEOBIA, describe some fundamentally new contributions to OBIA in the geographical context and, finally, summarize the current status with ideas for future developments.
26

Vitalitätsbestimmungen von Cryptosporidium-parvum-Oozysten in einem Zellkultursystem mittels Immunfluoreszenztechnik und computergestützter Bildanalyse

Wackwitz, Cathleen 07 November 2007 (has links) (PDF)
In dieser Arbeit wird eine neue Methode der Vitalitätsbestimmung von Cryptosporidium parvum-Oozysten beschrieben. Die gereinigten Oozysten wurden in einer HCT-8-zelllinie kultiviert und mittels IFAT ausgewertet. Um eine genaue Quantifizierung der fluoreszierenden Flächen vornehmen zu können, wurden die Bilder einer Bildanalysesoftware zugeführt und analysiert. Die Menge eingesäter Oozysten korrelierte signifikant mit den gemessenen Flächen intrazellulärer Entwicklungsstadien. In diesem System wurden verschiedene Feldisolate vergleichend getestet sowie die Vitalität thermisch inaktivierter Oozysten bestimmt.
27

Stofftransport- und Stoffumsatzprozesse in filamentösen Pilzpellets

Hille, Andrea January 2007 (has links)
Zugl.: Braunschweig, Techn. Univ., Diss., 2007
28

Interaktive und dynamische Visualisierung für die chirurgische Ausbildung und Interventionsplanung

Bade, Ragnar January 2008 (has links)
Zugl.: Magdeburg, Univ., Diss., 2008
29

Computational Image Analysis, Evolutionary Bioinformatics and Modeling of Molecular Interactions of Tau

Sündermann, Frederik 22 June 2016 (has links)
The microtuble-associated protein tau is known to regulate neuronal micro- tubule dynamics and is involved in several neurodegenerative diseases collec- tively called tauopathies. Besides the formation of tau-containing aggregates this group of diseases is characterized by changes on different anatomical lev- els in the nervous system. Morphological changes in the dendritic arbor of neu- rons or subcellular compartments can be investigated with microscopy-based and image informatical methods. Furthermore, the functional processes that constitute these changes can be predicted with bioinformatical methods and based on these predictions investigated with biological experiments. Two different bioinformatical disciplines contribute to the study of neurobio- logical processes. Due to advances in microscopy and imaging coupled to the tremendous advances in computer technology, image informatics techniques and workflows are necessary to analyze the acquired data with greater pre- cision. The classical bioinformatics on the other hand covers the analysis of molecular evolution, phylogeny and the prediction of protein function. This work aims to assist neurobiologists with computational methods in ongo- ing reasearch questions. The development of computer-assisted or fully auto- mated workflows for image analysis has been achieved on different levels. A machine learning algorithm has been trained to determine the density of neu- rons in tissues. Workflows for analysis of morphological changes of dendritic arbors, like process thickness or branching pattern, have been implemented. Existing workflows for dendritic spine analysis have been optimized and the volume and movement behavior of subcellular compartments like ribonucle- oparticles have been analyzed. Image analysis workflows have been adapted for the analysis of molecular distributions after photoactivation. Additionally, techniques from data mining workflows have been adapted to extract and filter trajectories from single molecule tracking approaches to assist the inferrence of biophysical parameters. Sequence data from public available databases have been collected to recon- struct tau and other related sequences in a broad range of species to infer phy- logenetic trees and to perform hidden-Markov-model analysis. Using this ap- proach it has been possible to illuminate the relations in the MAPT/2/4 family and predict putative functional sequence motifs for further bioinformatical or biological investigations.
30

Selbstauskünfte eines Bildwerks - Die Tafel des Jüngsten Gerichts in Weesenstein: Arbeitsbericht

Schellenberger, Simona 21 February 2020 (has links)
Die Bildanalyse beschäftigt sich mit der Tafel des Jüngsten Gerichts im Schloss Weesenstein. Welche Provenienz läßt sich für das Gemälde nachweisen? Auf welchen ehemaligen Präsentationszusammenhang weisen die verwendeten Motive, Figuren und Textinhalte? Der Beitrag bietet ebenfalls diverse kulturhistorische Zusammenhänge, die sich aus den Motiven herleiten lassen.

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