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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.
1

Optical Scanning Holography for 3-D Imaging of Fluorescent Objects in Turbid Media

Kim, Taegeun 16 December 1997 (has links)
A holographic recording method using an optical heterodyne 2-D scanning technique for 3-D imaging of fluorescent objects in turbid media is described and experimentally demonstrated. For the first time, 3-D imaging of fluorescentobjects in turbid media by a holographic method is achieved, and the diffused photon rejecting process through a heterodyne technique is analyzed. We also propose and realize a multiplexing and a digital decoding method for removing twin-image noise in optical scanning holography. The holographic method studied can be applied to 3-D biomedical imaging of fluorescent objects in turbid media as well as diffusely reflecting objects. / Master of Science
2

Comparative morphology three dimensional renderings of the glossopodia North American Isoetes ligules /

Shaw, Shane William. January 2004 (has links)
Thesis (M.S.)--Miami University, Dept. of Botany, 2004. / Title from first page of PDF document. Includes bibliographical references (p. 31-33).
3

New approaches to automatic 3-D and 2-D 3-D face recognition

Jahanbin, Sina 01 June 2011 (has links)
Automatic face recognition has attracted the attention of many research institutes, commercial industries, and government agencies in the past few years mainly due to the emergence of numerous applications, such as surveillance, access control to secure facilities, and airport screening. Almost all of the research on the early days of face recognition was focused on using 2-D (intensity/portrait) images of the face. While several sophisticated 2-D solutions have been proposed, unbiased evaluation studies show that their collective performance remains unsatisfactory, and degrades significantly with variations in lighting condition, face position, makeup, or existence of non-neutral facial expressions. Recent developments in 3-D imaging technology has made cheaper, quicker and more reliable acquisition of 3-D facial models a reality. These 3-D facial models contain information about the anatomical structure of the face that remains constant under variable lighting conditions, facial makeup, and pose variations. Thus, researchers are considering to utilize 3-D structure of the face alone or in combination with 2-D information to alleviate inherent limitations of 2-D images and attain better performance. Published 3-D face recognition algorithms have demonstrated promising results confirming the effectiveness of 3-D facial models in dealing with the above mentioned factors contributing to the failure of 2-D face recognition systems. However, the majority of these 3-D algorithms are extensions of conventional 2-D approaches, where intensity images are simply replaced by 3-D models rendered as range images. These algorithms are not specifically tailored to exploit abundant geometric and anthropometric clues available in 3-D facial models. In this dissertation we introduce innovative 3-D and 2-D+3-D facial measurements (features) that effectively describe the geometric characteristics of the corresponding faces. Some of the features described in this dissertation, as well as many features proposed in the literature are defined around or between meaningful facial landmarks (fiducial points). In order to reach our goal of designing an accurate automatic face recognition system, we also propose a novel algorithm combining 3-D (range) and 2-D (portrait) Gabor clues to pinpoint a number of points with meaningful anthropometric definitions with significantly better accuracies than those achievable using a single modality alone. This dissertation is organized as follows. In Chapter 1, various biometric modalities are introduced and the advantages of the facial biometrics over other modalities are discussed. The discussion in Chapter 1 is continued with introduction of the face recognition’s modes of operation followed by some current and potential future applications. The problem statement of this dissertation is also included in this chapter. In Chapter 2, an extensive review of the successful 2-D, 3-D, and 2-D+3-D face recognition algorithms are provided. Chapter 3 presents the details of our innovative 3-D and 2-D+3-D face features, as well as our accurate fiducial point detection algorithm. Conclusions and directions for future extensions are presented in Chapter 4. / text
4

Comparative Morphology of the Glossopodia of Three North American Isoetes Ligules

Shaw, Shane William 02 November 2004 (has links)
No description available.
5

Characterisation of porosity and root growth in a sodic texture-contrast soil

Jassogne, Laurence January 2009 (has links)
In Australia a class of soils known as sodic duplex soils covers approximately 20% of the continent. Their defining characteristic is a sharp texture contrast between the A (or E) and B horizon. The upper B horizon at the point of contact with the E horizon is often highly sodic and of such a high strength that root growth and proliferation, water conductivity, aeration, water storage and water uptake are restricted. Roots growing in these soils rely on channels created by previous roots or cracks arising from shrink– swell forces associated with seasonal wetting and drying. It has been suggested that by increasing the number of these channels in the subsoil, the structure and permeability of the subsoil would be increased as would be the number of preferential pathways for following generation roots. A biological approach for improving soil macroporosity would be to use plants that can grow through that hostile layer creating new channels. This is known as the primer plant concept. This concept is based on a better understanding of root soil interactions. It is accepted that root growth is influenced by the soil structure and the soil structure is influenced by root growth. However, a lot of these dynamics are still unknown. This project aims to contribute to improving that knowledge by investigating the use of modern techniques to study plant/root interactions in duplex soils. First macroporosity and mesoporosity were characterized in three dimensions using medical computer tomography and micro-tomography. Then the imaging methodology was improved by using a local and adaptive threshold technique based on indicator kriging instead of a global threshold. Using this new methodology, changes in porosity were analysed in intact samples when three different plant species were grown for 12 weeks. The plants were canola (Brassica napus); lucerne (Medicago sativum) and saltbush (Atriplex nummularia) hypothesizing saltbush would change the porosity more because it is a native plant species based on the primer plant concept. The results showed that the porosity changed significantly after root growth but no ii differences were found between plant species. The changes could also not all be attributed to root growth because cracks were also formed after 12 weeks. Therefore, the living roots were visualized and characterized using a new tracing algorithm 'rootviz'. This revealed that saltbush was growing more roots down through the profile. Lucerne seemed to grow roots down the profile as well but to a lesser extend. Both of these plants seemed to have more geotropic features than canola that seemed to grow more laterals and had a more exploratory behaviour.
6

A Bio-Assembly, Mosaic Building, and Informatics System for Cell Biology

Blaylock, April Deirdre January 2007 (has links)
In the field of regenerative medicine, there is a need to develop technologies that can increase the overall efficiency of imaging and expanding cells in culture and in complex heterogeneous arrangements necessary for tissue construction. Long-term live cell imaging has the potential to significantly enhance our understanding of intercellular signaling pathways and the dependence of phenotype on cell arrangement. A transdisciplinary approach has been taken to bridge the fields of cell biology, robotics, and photonics to create a long-term live cell imaging system capable of single cell handling as well as the acquisition of multiple types of data needed for data mining and a general informatics approach to cell culture. A Bio-Assembly Mosaic Builder and Informatics (BAMBI) system was designed and developed using custom software to control a 3-axis stage manufactured by Galil Inc, and custom 1-axis micromanipulator for robotic operations. The software also employs a Sony charged-coupled device sensor for real-time image feedback and data acquisition. The system is mounted on a Carl Zeiss Axiovert 200 inverted microscope. Custom-built environmental controls are used to maintain the temperature, humidity, and gas conditions for extended live cell work. The software was designed using Visual C++ for the Windows PC platform using an object orientated and modular design methodology to allow the BAMBI software to continue to grow with new tasks and demands as needed. The modular approach keeps functional groups of code within context boundaries allowing for easy removal, addition, or changes of functions without compromising the usability of the whole system. BAMBI has been used to image cells within a novel cell culture chamber that constricts cell growth to a true monolayer for high-resolution imaging. In one specific application, BAMBI was also used to characterize and track the development of individual Colony Forming Units (CFU) over the five-day culture period in 5-day CFU-Hill colony assays. The integrated system successfully enabled the tracking and identification of cell types responsible for the formation of the CFU-Hill colonies (a putative endothelial stem cell). BAMBI has been used to isolate single hematopoietic stem cell (HSC) candidate cells, accumulate long-term live cell images, and then return these cells back to the in-vivo environment for further characterization. From these results, further data mining and lineage informatics suggested a novel way to isolate and purify HSCs. Studies such as these are the fundamental next step in developing new therapies for regenerative medicine in the future.
7

A Bio-Assembly, Mosaic Building, and Informatics System for Cell Biology

Blaylock, April Deirdre January 2007 (has links)
In the field of regenerative medicine, there is a need to develop technologies that can increase the overall efficiency of imaging and expanding cells in culture and in complex heterogeneous arrangements necessary for tissue construction. Long-term live cell imaging has the potential to significantly enhance our understanding of intercellular signaling pathways and the dependence of phenotype on cell arrangement. A transdisciplinary approach has been taken to bridge the fields of cell biology, robotics, and photonics to create a long-term live cell imaging system capable of single cell handling as well as the acquisition of multiple types of data needed for data mining and a general informatics approach to cell culture. A Bio-Assembly Mosaic Builder and Informatics (BAMBI) system was designed and developed using custom software to control a 3-axis stage manufactured by Galil Inc, and custom 1-axis micromanipulator for robotic operations. The software also employs a Sony charged-coupled device sensor for real-time image feedback and data acquisition. The system is mounted on a Carl Zeiss Axiovert 200 inverted microscope. Custom-built environmental controls are used to maintain the temperature, humidity, and gas conditions for extended live cell work. The software was designed using Visual C++ for the Windows PC platform using an object orientated and modular design methodology to allow the BAMBI software to continue to grow with new tasks and demands as needed. The modular approach keeps functional groups of code within context boundaries allowing for easy removal, addition, or changes of functions without compromising the usability of the whole system. BAMBI has been used to image cells within a novel cell culture chamber that constricts cell growth to a true monolayer for high-resolution imaging. In one specific application, BAMBI was also used to characterize and track the development of individual Colony Forming Units (CFU) over the five-day culture period in 5-day CFU-Hill colony assays. The integrated system successfully enabled the tracking and identification of cell types responsible for the formation of the CFU-Hill colonies (a putative endothelial stem cell). BAMBI has been used to isolate single hematopoietic stem cell (HSC) candidate cells, accumulate long-term live cell images, and then return these cells back to the in-vivo environment for further characterization. From these results, further data mining and lineage informatics suggested a novel way to isolate and purify HSCs. Studies such as these are the fundamental next step in developing new therapies for regenerative medicine in the future.
8

Digitization and Digital Preservation of P.Herc. 817

Bischoff, Marissa Anne 14 December 2023 (has links) (PDF)
The large cache of scrolls from Herculaneum were opened to scholars in spite of and because of the destruction of the volcano and damaging unfurling techniques. The fragments inherited have been studied closely by scholars. Digitization and technological work on the Herculaneum papyri, including the important infrared imaging completed by BYU in the early 2000s, and the 3-D imaging and inchoate virtual unwrapping technology by EduceLab, have amplified and aided scholarship on the scrolls and will continue to do so. P.Herc. 817 is a unique Latin text within the collection that has been heavily studied by scholars due to its fascinating subject matter on the Battle of Actium and Cleopatra and its readability. This fragment serves as a case study to demonstrate the value of each set of digital images in transcription and interpretation research, which suggests at the value of the varying digital images for other Herculaneum fragments. I closely compare digital surrogates of P.Herc. 817 including the early 2000s infrared images, 1960's era negatives, and recent 3-D images with the original artifacts as seen at the Biblioteca Nazionale in July 2023. This autopsy of versions of P.Herc. 817 substantiates the need for scholars to use all available digital images in concert with the original papyri when doing scholarly work. It also reinforces the need for digital stewardship and preservation of each distinct image set. Finally, a hypothetical case study is offered to show the loss to scholarship if the digital images and originals were lost and solely secondary sources remained. Each image set offers value and captures a moment in time of the papyri. As technology continues to progress and excitingly unlocks unseen papyri, care needs to be taken to safeguard and digitally preserve the new along with the older data sets.
9

Characterization and Helicopter Flight Test of 3-D Imaging Flash LIDAR Technology for Safe, Autonomous, and Precise Planetary Landing

Roback, Vincent Eric 17 September 2012 (has links)
Two flash lidars, integrated from a number of cutting-edge components from industry and NASA, are lab characterized and flight tested under the Autonomous Landing and Hazard Avoidance (ALHAT) project (in its fourth development and field test cycle) which is seeking to develop a guidance, navigation, and control (GNC) and sensing system based on lidar technology capable of enabling safe, precise human-crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The flash lidars incorporate pioneering 3-D imaging cameras based on Indium-Gallium-Arsenide Avalanche Photo Diode (InGaAs APD) and novel micro-electronic technology for a 128 x 128 pixel array operating at 30 Hz, high pulse-energy 1.06 ?m Nd:YAG lasers, and high performance transmitter and receiver fixed and zoom optics. The two flash lidars are characterized on the NASA-Langley Research Center (LaRC) Sensor Test Range, integrated with other portions of the ALHAT GNC system from around the country into an instrument pod at NASA-JPL, integrated onto an Erickson Aircrane Helicopter at NASA-Dryden, and flight tested at the Edwards AFB Rogers dry lakebed over a field of human-made geometric hazards. Results show that the maximum operational range goal of 1000m is met and exceeded up to a value of 1200m, that the range precision goal of 8 cm is marginally met, and that the transmitter zoom optics divergence needs to be extended another eight degrees to meet the zoom goal 6° to 24°. Several hazards are imaged at medium ranges to provide three-dimensional Digital Elevation Map (DEM) information. / Master of Science

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