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Dissertations / Theses on the topic 'Photogrammetry'
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Masaad, Elshami M. "Close-range photogrammetry based on digital imagery analysis : real-time photogrammetric measurements from video imagery." Thesis, University of Manchester, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338480.
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Boman, Jakob. "Tree Species ClassicationUsing Terrestrial Photogrammetry." Thesis, Umeå universitet, Institutionen för datavetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-80792.
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This thesis investigates how texture classification can be used to automatically classify tree species from image of bark texture. The texture analysis methods evaluated in the thesis are, grey level co-occurrence matrix (GLCM), two different wavelet texture analysis methods and finally the scale-invariant feature transform. To evaluate the methods two classifiers, a linear support vector machine (SVM) and a kernel based import vector machine (IVM) was used. The tree species that were classified were Scotch Pine and Norwegian Spruce and the auxiliary class ground. Three experiments were conducted to test the methods. The experiments used subimages of bark extracted from terrestrial photogrammetry images. For each sub-image, the X ,Y and Z coordinates were available. Thefirst experiment compared the methods by classifying each sub-image individually based on image data alone. In the second experiment the spatial data was added. Additionally feature selection was performed in both experiments to determine the most discriminating features. In the final experiment individual trees were classified by clustering all data from each tree.For sub-image classification, the addition of spatial data increased the overall accuracy for the best method from 75.7% to 94.9% The best method was IVM on GLCM textural features. The most discriminating textural feature was homogeneity in the horizontal direction. The best methods to classify individual trees were SVM with GLCM with an overall accuracy of 88%.In summary, the methods was found to be promising for tree bark classification. However, the individual tree results were based on a low number of trees. To establish the methods' true usefulness, testing on a larger number of trees is necessary.
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Smith, Douglas G. "Digital photogrammetry for elevation modelling." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362992.
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Kernell, Björn. "Improving Photogrammetry using Semantic Segmentation." Thesis, Linköpings universitet, Datorseende, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-148491.
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3D reconstruction is the process of constructing a three-dimensional model from images. It contains multiple steps where each step can induce errors. When doing 3D reconstruction of outdoor scenes, there are some types of scene content that regularly cause problems and affect the resulting 3D model. Two of these are water, due to its fluctuating nature, and sky because of it containing no useful (3D) data. These areas cause different problems throughout the process and do generally not benefit it in any way. Therefore, masking them early in the reconstruction chain could be a useful step in an outdoor scene reconstruction pipeline. Manual masking of images is a time-consuming and boring task and it gets very tedious for big data sets which are often used in large scale 3D reconstructions. This master thesis explores if this can be done automatically using Convolutional Neural Networks for semantic segmentation, and to what degree the masking would benefit a 3D reconstruction pipeline.3D-rekonstruktion är teknologin bakom att skapa 3D-modeller utifrån bilder. Det är en process med många steg där varje steg kan medföra fel. Vid 3D-rekonstruktion av stora utomhusmiljöer finns det vissa typer av bildinnehåll som ofta ställer till problem. Två av dessa är vatten och himmel. Vatten är problematiskt då det kan fluktuera mycket från bild till bild samt att det kan innehålla reflektioner som ger olika utseenden från olika vinklar. Himmel å andra sidan ska aldrig ge upphov till 3D-information varför den lika gärna kan maskas bort. Manuell maskning av bilder är väldigt tidskrävande och dyrt. Detta examensarbete undersöker huruvida denna maskning kan göras automatiskt med Faltningsnät för Semantisk Segmentering och hur detta skulle kunna förbättra en 3D-rekonstruktionsprocess.
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Forno, C. "A camera for high accuracy photogrammetry." Thesis, University of Surrey, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277157.
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Evans, S. E. K. "Applied photogrammetry in orthopaedic implant manufacture." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3020338/.
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Bergsjö, Joline. "Photogrammetric point cloud generation and surface interpolation for change detection." Thesis, KTH, Geodesi och satellitpositionering, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190882.
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In recent years the science revolving image matching algorithms has gotten an upswing mostly due to its benefits in computer vision. This has led to new opportunities for photogrammetric methods to compete with LiDAR data when it comes to 3D-point clouds and generating surface models. In Sweden a project to create a high resolution national height model started in 2009 and today almost the entirety of Sweden has been scanned with LiDAR sensors. The objective for this project is to achieve a height model with high spatial resolution and high accuracy in height. As for today no update of this model is planned in the project so it’s up to each municipality or company who needs a recent height model to update themselves. This thesis aims to investigate the benefits and shortcomings of using photogrammetric measures for generating and updating surface models. Two image matching software are used, ERDAS photogrammetry and Spacemetric Keystone, to generate a 3D point cloud of a rural area in Botkyrka municipality. The point clouds are interpolated into surface models using different interpolation percentiles and different resolutions. The photogrammetric point clouds are evaluated on how well they fit a reference point cloud, the surfaces are evaluated on how they are affected by the different interpolation percentiles and image resolutions. An analysis to see if the accuracy improves when the point cloud is interpolated into a surface. The result shows that photogrammetric point clouds follows the profile of the ground well but contains a lot of noise in the forest covered areas. A lower image resolution improves the accuracy for the forest feature in the surfaces. The results also show that noise-reduction is essential to generate a surface with decent accuracy. Furthermore, the results identify problem areas in dry deciduous forest where the photogrammetric method fails to capture the forest.
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Seedahmed, Gamal H. "On the suitability of conic sections in a single-photo resection, camera calibration, and photogrammetric triangulation." Columbus, Ohio Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1073186865.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xix, 138 p.; also includes graphics (some col). Includes abstract and vita. Advisor: Anton F. Schenk, Dept. of Geodetic Science and Surveying. Includes bibliographical references (p. 130-138).
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Kuzu, Yasemin. "Volumetric object reconstruction by means of photogrammetry." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=970680333.
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Ireland, Darren Scott. "Mass estimation of Weddell Seals through photogrammetry." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/ireland/IrelandD1204.pdf.
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Food resources of pelagic marine predators have traditionally been difficult to monitor and annual monitoring of food-resource availability is not currently feasible for the Weddell seal (Leptonychotes wedellii) population in Erebus Bay, Antarctica. Body mass measurements of parturient females, or their weaned pups, on an annual basis may be used as an indicator of food availability during the previous year and also provide a link between population vital rates and environmental fluctuation. Traditional methods of acquiring mass measurements, including physical restraint and/or chemical immobilization, limit the ability to sample adequately large numbers of individuals from the population of interest. Previous researchers have developed methods to estimate the mass of large seals using scaled photographs, but later application of these methods have not explicitly included uncertainty around estimates derived from predictive equations. I therefore developed the equipment and methods for estimating the mass of Weddell seals using digital photographs and image-analysis software. I then applied the method at a small scale to determine how prediction intervals may be incorporated into calculations based on mass estimates and what affect the explicit use of these intervals would have on the ability to detect differences between the mass of individuals or groups of seals. Scaled photographs of adult female and pup Weddell seals were taken from overhead, ground-level side, and ground-level head or tail perspectives. Morphometric measurements from scaled photographs (photogrammetric measurements) were then correlated using regression against the measured mass at the time of photography. Sampling occurred throughout the nursing period in order to build regression models over a wide range of masses. Resulting regression models predict the mass of adult female seals to within ±13.8% of estimated mass, and ±25.9% of estimated mass for pups. In an application of the method, differences in mass transfer between experienced and inexperienced maternal females and their pups were detected when prediction intervals were explicitly included. Detection of differences between individual seals may not be possible when prediction intervals are included with mass estimates, but estimated mass measurements should be useful for comparing mean differences across a population between years in relation to environmental variation.
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Jumpasut, Arin. "Photogrammetry in impact engineering using regular targets." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526477.
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Joy, Christopher Iain Harold. "GPS assisted helicopter photogrammetry for highway profiling." Thesis, University of Nottingham, 1998. http://eprints.nottingham.ac.uk/11462/.
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Roads are an integral part of today's lifestyle. Indeed, a modern and efficient economy requires a satisfactory road network. The road network in the United Kingdom faces ever-increasing demands with 94% of passenger travel and 92% of freight transport undertaken by road. Maintenance of the network is essential. Prior to the commencement of any maintenance scheme, an accurate highway profile is measured by undertaking a detailed topographic survey of the road surface and the adjacent verges. Traditionally, this is carried out by land surveyors using, for example, a theodolite, EDM and level. Highway surveying by traditional methods is a slow, costly and dangerous process. A photogrammetric technique was devised by Photarc Surveys Ltd of Harrogate, UK to reduce the problems of speed, cost and safety. This helicopter based photographic system can yield topographic data at up to ±5mm rmse through photogrammetric analysis. It is necessary to install ground control points on the hard shoulder for use in the photogrammetric analysis. This research investigates the potential of both conventional aerial triangulation and in-flight GPS assisted aerial triangulation for reducing this ground control requirement. The original photographic system is extended to integrate a GPS positioning system and the performance of this system is assessed through a series of field trials. The results of the research show that the camera can be positioned by the GPS system to within 5 centimetres. The GPS positions can be included in the aerial triangulation to further reduce the requirement for ground control. It is shown that for mapping at the ± 5mm rmse level, there is no potential for height control reduction, even when GPS positions are used. However for mapping at up to ± 20mm, the GPS positions can enable a significant reduction in ground control.
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Faulkner, Sean. "Photogrammetry of 3D footwear impressions forensic applications." Thesis, Faulkner, Sean (2017) Photogrammetry of 3D footwear impressions forensic applications. Masters by Coursework thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/37835/.
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During a forensic investigation, the recording of evidence in high detail with no distortion and limiting the loss of information is paramount. This could mean the difference between finding a possible offender or the removal of an innocent party from an investigation. Although the current method of recording three dimensional footprints records fine and minimises distortion, it still suffers from a loss of information due to the conversion of a three-dimensional subject into a two-dimensional image. Recent studies into the uses of photogrammetry has highlighted its usefulness in recording an object with high detail and little to no distortion while maximizing the amount of information retained in the three-dimensional model.
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Valois, Jean-Sébastien. "Monocular camera calibration assessment for mid-range photogrammetry." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33348.
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The CCD (Charge Coupled Device) image formation theory is at the foundation of 3D vision systems. Ideally, a five-element block diagram can model this process. The first block represents the nonlinear distortions caused by camera lenses. The second and third elements gather the low-pass filter effects due to lens aberrations and CCD phenomenon. A fourth block illustrates the quantization effects induced by a series of discrete photosensitive elements on the CCD and by the A/D conversion for analog cameras. The last block represents the addition of random noise on the discrete signal. Because step-like luminance transitions undergoing lens distortion remain step-like, it is possible to precisely correct for the distortions after the edge localization. The efficient distortion correction process is exactly where the camera lens calibration challenge resides. The calibration exercise also seeks the intrinsic and extrinsic camera parameters, i.e. the information that relates to the camera optics and the information that describes the location and orientation of the camera in 3D space. This thesis presents a review and evaluation of several methods designed for optimal accuracy on the parameters evaluation. (Abstract shortened by UMI.)
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Zheng, Benrui. "Positioning sensor by combining optical projection and photogrammetry." Thesis, The University of North Carolina at Charlotte, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3625067.
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Six spatial parameters, (x, y, z) for translation, and pitch, roll, and yaw for rotation, are used to describe the 3-dimensional position and orientation of a rigid body—the 6 degrees of freedom (DOF). The ability to measure these parameters is required in a diverse range of applications including machine tool metrology, robot calibration, motion control, motion analysis, and reconstructive surgery. However, there are limitations associated with the currently available measurement systems. Shortcomings include some of the following: short dynamic range, limited accuracy, line of sight restrictions, and capital cost. The objective of this dissertation was to develop a new metrology system that overcomes line of sight restrictions, reduces system costs, allows large dynamic range and has the potential to provide high measurement accuracy.
The new metrology system proposed in this dissertation is based on a combination of photogrammetry and optical pattern projection. This system has the potential to enable real-time measurement of a small lightweight module's location. The module generates an optical pattern that is observable on the surrounding walls, and photogrammetry is used to measure the absolute coordinates of features in the projected optical pattern with respect to a defined global coordinate system. By combining these absolute coordinates with the known angular information of the optical projection beams, a minimization algorithm can be used to extract the absolute coordinates and angular orientation of the module itself. The feasibility of the proposed metrology system was first proved through preliminary experimental tests. By using a module with a 7×7 dot matrix pattern, experimental agreement of 1 to 5 parts in 103 was obtained by translating the module over 0.9 m and by rotating it through 60°. The proposed metrology system was modeled through numerical simulations and factors affecting the uncertainty of the measurement were investigated. The simulation results demonstrate that optimum design of the projected pattern gives a lower associated measurement uncertainty than is possible by direct photogrammetric measurement with traditional tie points alone. Based on the simulation results, a few improvements have been made to the proposed metrology systems. These improvements include using a module with larger full view angle and larger number of dots, performing angle calibration for the module, using a virtual camera approach to determine the module location and employing multiple coordinates system for large range rotation measurement. With the new proposed virtual camera approach, experimental agreement at the level of 3 parts in 104 was observed for the one dimension translation test. The virtual camera approach is faster than the algorithm and an additional minimization analysis is no longer needed. In addition, the virtual camera approach offers an additional benefit that it is no longer necessary to identify all dots in the pattern and so is more amenable to use in realistic and usually complicated environments. A preliminary rotation test over 120° was conducted by tying three coordinate systems together. It was observed that the absolute values of the angle differences between the measured angle and the encoder reading are smaller than 0.23° for all measurements. It is found that this proposed metrology system has the ability to measure larger angle range (up to 360°) by using multiple coordinate systems. The uncertainty analysis of the proposed system was performed through Monte Carlo simulation and it was demonstrated that the experimental results are consistent with the analysis.
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Fiore, Paul D. (Paul David) 1963. "A custom computing framework for orientation and photogrammetry." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/16742.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 211-223).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
There is great demand today for real-time computer vision systems, with applications including image enhancement, target detection and surveillance, autonomous navigation, and scene reconstruction. These operations generally require extensive computing power; when multiple conventional processors and custom gate arrays are inappropriate, due to either excessive cost or risk, a class of devices known as Field-Programmable Gate Arrays (FPGAs) can be employed. FPGAs per the flexibility of a programmable solution and nearly the performance of a custom gate array. When implementing a custom algorithm in an FPGA, one must be more efficient than with a gate array technology. By tailoring the algorithms, architectures, and precisions, the gate count of an algorithm may be sufficiently reduced to t into an FPGA. The challenge is to perform this customization of the algorithm, while still maintaining the required performance. The techniques required to perform algorithmic optimization for FPGAs are scattered across many fields; what is currently lacking is a framework for utilizing all these well known and developing techniques. The purpose of this thesis is to develop this framework for orientation and photogrammetry systems.
by Paul D. Fiore.
Ph.D.
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Singels, Wynand. "An application of photogrammetry in the petrochemical industry." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/2296.
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Thesis (MScEng (Mathematical Sciences. Applied Mathematics))--Stellenbosch University, 2008.When building or improving a petrochemical plant, drawings are used extensively in the design process. However, existing petrochemical plants seldom match their drawings, or the drawings are lost, forcing the need to generate a 3D model of the structure of the plant. In this thesis photogrammetry is investigated as a method of generating a digital 3D model of an existing plant. Camera modeling, target extraction and 3D reconstruction are discussed in detail, and a real-world system is investigated.
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Sánchez, García Elena. "Photogrammetry and image processing techniques for beach monitoring." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/123956.
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[ES] Las playas son ambientes ecológicos sumamente valiosos donde a lo largo de una frágil franja de transición converge el entorno terrestre y el medio marino. Durante el último siglo, la mejora en la comprensión de los procesos físicos que ocurren en la zona costera se ha convertido en un asunto de máxima importancia. Para abordar una planificación coherente de la gestión costera se requiere tomar en consideración el dinamismo de los diferentes cambios morfológicos que caracterizan estos ambientes a distintas escalas espaciales y temporales.
El límite tierra-agua varía en función de la posición del nivel del mar y de la forma del perfil de playa que continuamente queda modelado por las olas incidentes. Intentar modelizar la respuesta de un paisaje tan voluble geomorfológicamente como las playas requiere disponer de múltiples medidas registradas con suficiente precisión para poder reconocer su respuesta frente a la acción de los distintos agentes geomórficos. Para ello resulta esencial disponer de diferentes sistemas de monitorización capaces de registrar de forma sistemática la línea de costa con exactitud y efectividad. Se requieren nuevos métodos y herramientas informáticas que permitan capturar, caracterizar y analizar eficientemente la información con el objeto de obtener indicadores con significación geomorfológica de calidad. En esto radica el objetivo de la presente tesis doctoral, centrándose en el desarrollo de herramientas y procedimientos eficientes para la monitorización costera mediante el uso de imágenes satelitales y fotografías terrestres.
El trabajo aporta soluciones de procesamiento de imágenes de satélite y fotogramétricas a científicos, ingenieros y gestores costeros, proporcionando resultados que evidencian la gran utilidad de estas técnicas viables y de bajo coste para la monitorización costera. Mediante ellas se puede convertir información pública existente y de libre acceso (imágenes satelitales, datos de video cámaras o fotografías de la ciudadanía) en datos de alta calidad para el monitoreo de los cambios morfológicos de las playas, y lograr así una consiguiente gestión sostenible de los recursos costeros.[CAT] Les platges són ambients ecològics summament valuosos on al llarg d'una feble franja de transició convergeix l'entorn terrestre i el medi marí. En l'últim segle, la millora en la comprensió dels processos físics que ocorren en la zona costanera s'ha convertit en un assumpte de màxima importància. Per a abordar una planificació coherent de la gestió costanera es requereix prendre en consideració el dinamisme dels diferents canvis morfològics que caracteritzen aquests ambients a diferents escales espacials i temporals. El límit terra-aigua varia en funció de la posició del nivell del mar i de la forma del perfil de platja que contínuament queda modelat per les ones incidents. Intentar modelitzar la resposta d'un paisatge tan voluble geomorfològicament com les platges requereix disposar de múltiples mesures registrades amb suficient precisió per poder reconèixer la seua resposta enfront de l'acció dels diferents agents geomòrfics. Per tant, resulta essencial disposar de diferents sistemes de monitoratge capaços de registrar de forma sistemàtica la línia de costa amb exactitud i efectivitat. Es requereixen nous mètodes i eines informàtiques que permeten capturar, caracteritzar i analitzar eficientment la informació a fi d'obtindre indicadors amb significació geomorfològica de qualitat. En això radica l'objectiu de la present tesi doctoral, que es centra en el desenvolupament d'eines i procediments eficients per al monitoratge costaner mitjançant l'ús d'imatges de satèl·lit i fotografies terrestres. El treball aporta solucions de processament d'imatges de satèl·lit i fotogramètriques a científics, enginyers, polítics i gestors costaners, proporcionant resultats que evidencien la gran utilitat d'aquestes tècniques factibles i de baix cost per a la monitorització costanera. Mitjançant aquestes es pot convertir informació pública existent i de lliure accés (imatges de satèl·lit, dades de videocàmeres o fotografies de la ciutadania) en dades d'alta qualitat per al monitoratge dels canvis morfològics de les platges, i aconseguir així una consegüent gestió sostenible dels recursos costaners.
[EN] Beaches are extremely valuable ecological spaces where terrestrial and marine environments converge along a fragile transition strip. An improvement in our understanding of the physical processes that occur in the coastal zone has become increasingly important during the last century. To approach a coherent planning of coastal management it is necessary to consider the dynamism of the various morphological changes that characterize these environments at different spatial and temporal scales. The land-water boundary varies according to the sea level and the shape of a beach profile that is continuously modelled by incident waves. Attempting to model the response of a landscape as geomorphologically volatile as beaches requires multiple precise measurements to recognize responses to the actions of various geomorphic agents. It is therefore essential to have monitoring systems capable of systematically recording the shoreline accurately and effectively. New methods and tools are required to efficiently capture, characterize, and analyze information - and so obtain geomorphologically significant indicators. This is the aim of the doctoral thesis, focusing on the development of tools and procedures for coastal monitoring using satellite images and terrestrial photographs. The work brings satellite image processing and photogrammetric solutions to scientists, engineers, and coastal managers by providing results that demonstrate the usefulness of these viable and low-cost techniques. Existing and freely accessible public information (satellite images, video-derived data, or crowd-sourced photographs) can be converted into high quality data for monitoring morphological changes on beaches and thus help achieve a sustainable management of coastal resources.
Agradecer al Ministerio de Educación, Cultura y Deporte del Gobierno de España por la beca predoctoral FPU, y por las ayudas de movilidad concedidas, que han permitido que esta Tesis Doctoral fuera una realidad. También a los proyectos AICO/2015/098 y CGL2015-69906-R financiados respectivamente por la Generalitat Valenciana y por el Ministerio de Economía y Competitividad.
Sánchez García, E. (2019). Photogrammetry and image processing techniques for beach monitoring [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/123956
TESIS
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Hull, Simon Antony. "Digital photogrammetry for visualisation in architecture and archaeology." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/4987.
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Bibliography: leaves 117-125.The task of recording our physical heritage is of significant importance: our past cannot be divorced from the present and it plays an integral part in the shaping of our future. This applies not only to structures that are hundreds of years old, but relatively more recent architectural structures also require adequate documentation if they are to be preserved for future generations. In recording such structures, the traditional 2D methods are proving inadequate. It will be beneficial to conservationists, archaeologists, researchers, historians and students alike if accurate and extensive digital 3D models of archaeological structures can be generated. This thesis investigates a method of creating such models, using digital photogrammetry. Three different types of model were generated: 1. the simple CAD (Computer Aided Design) model; 2. an amalgamation of 3D line drawings; and 3. an accurate surface model of the building using DSMs (Digital Surface Models) and orthophotos.
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Kendler, Johnathan M. "Evaluating methods for implementing photogrammetric sensor platforms with various Lidar components for use with close and mid-range particle detection systems." abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1460763.
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Korpela, Ilkka. "Individual tree measurements by means of digital aerial photogrammetry." Helsinki : Finnish Forest Research Institute, Finnish Society of Forest Science, 2004. http://catalog.hathitrust.org/api/volumes/oclc/55872310.html.
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Walstra, Jan. "Historical aerial photographs and digital photogrammetry for landslide assessment." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/2501.
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This study demonstrates the value of historical aerial photographs as a source for monitoring long-term landslide evolution, which can be unlocked by using appropriate photogrammetric methods. The understanding of landslide mechanisms requires extensive data records; a literature review identified quantitative data on surface movements as a key element for their analysis. It is generally acknowledged that, owing to the flexibility and high degree of automation of modern digital photogrammetric techniques, it is possible to derive detailed quantitative data from aerial photographs. In spite of the relative ease of such techniques, there is only scarce research available on data quality that can be achieved using commonly available material, hence the motivation of this study. In two landslide case-studies (the Mam Tor and East Pentwyn landslides) the different types of products were explored, that can be derived from historical aerial photographs. These products comprised geomorphological maps, automatically derived elevation models (DEMs) and displacement vectors. They proved to be useful and sufficiently accurate for monitoring landslide evolution. Comparison with independent survey data showed good consistency, hence validating the techniques used. A wide range of imagery was used in terms of quality, media and format. Analysis of the combined datasets resulted in improvements to the stochastic model and establishment of a relationship between image ground resolution and data accuracy. Undetected systematic effects provided a limiting constraint to the accuracy of the derived data, but the datasets proved insufficient to quantify each factor individually. An important advancement in digital photogrammetry is image matching, which allows automation of various stages of the working chain. However, it appeared that the radiometric quality of historical images may not always assure good results, both for extracting DEMs and vectors using automatic methods. It can be concluded that the photographic archive can provide invaluable data for landslide studies, when modern photogrammetric techniques are being used. As ever, independent and appropriate checks should always be included in any photogrammetric design.
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Merel, Andre Philip. "The monitoring of soil surface change using analytical photogrammetry." Thesis, University of Portsmouth, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.482087.
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Pope, A. J. "Recent change of Svalbard glaciers quantified using digital photogrammetry." Thesis, Swansea University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638550.
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Understanding the response of glaciers to climate change is critical if estimates of future sea level rise are to be better constrained. A significant portion of recent sea level rise is thought to be from small glaciers, unfortunately these are scattered around the world making their contribution extremely difficult to quantify. Contributions tend to be reported for regions or groupings of glaciers and one of the regions with the largest potential contribution is the Arctic. This region has been identified as being extremely sensitive to climate fluctuations and is expected to be one of the first regions to respond to future climate change. The aim of this research is to quantify the surface change two key glaciers on Svalbard, one of the largest groupings, of glaciers in the Arctic. Surface change will be quantified through the use of Digital Elevation Models (DEMs) derived from aerial images. The quality of the derived surface is dependent on the quality of the ground data used to generate and validate the model. For this reason, extensive field work was conducted to install a network of accurate GPS points around the study glaciers. A Failure Warning Model (FWM) method is used to assess the reliability of the DEMs and the technique is developed through the implementation of a Multiple input Failure Warning Model (MiFWM) method that is more robust. This thesis shows that both study glaciers have experienced significant change during the study period. The calculated rates of change were comparable both to other ground based estimates and other photogrammetric estimates. In addition, the results do not contradict the suggestion that ground based monitoring methods consistently underestimate glaciers contribution to sea level.
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Papadaki, Helen. "Automated measurement of complx engineering surfaces using multistation photogrammetry." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401731.
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Miguel, Olivier. "A Low-Cost Custom Knee Brace Via Smartphone Photogrammetry." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38746.
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This thesis provided the foundational work for a low-cost three-dimensional (3D) printed custom knee brace. Specifically, the objective was to research, develop and implement a novel workflow aimed to be easy to use and available to anyone who has access to a smartphone camera and 3D printing services. The developed workflow was used to manufacture two prototypes which proved valuable in the design iterations. As a result, an improved hinge was designed which has increased mechanical strength. Additionally, a smartphone photogrammetry validation study was included which provided preliminary results on the accuracy and precision. This novel measurement method has the potential to require little training and could be disseminated through video instructions posted online. The intention is to enable the patient to collect their own “3D scan” with the help of a friend or family member, effectively removing the need to book an appointment simply for collecting custom measurements. Lastly, it would allow the clinician to focus all their time on clinically relevant design tasks such as checking alignment, fit and comfort, which could all potentially be improved by adopting such digital methods. The ultimate vision for this work is to enable manufacturing of better custom knee braces at a reduce cost which are easily accessible for low-income populations.
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Gonzales, Jack Joseph. "Comparing UAV and Pole Photogrammetry for Monitoring Beach Erosion." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/104997.
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Sandy beaches are vulnerable to extreme erosion during large storms, as well as gradual erosion processes over months and years. Without monitoring and adaptation strategies, erosion can put people, homes, and other infrastructure at risk. To effectively manage beach resources and respond to erosion hazards, coastal managers must have a reliable means of surveying the beach to monitor erosion and accretion. These elevation surveys typically incorporate traditional ground-based surveying methods or lidar surveys flown from large, fixed-wing aircraft. While both strategies are effective, advancements in photogrammetric technology offers a new solution for topographic surveying: Structure from Motion (SfM). Using a set of overlapping aerial photographs, the SfM workflow can generate accurate topographic surveys, and promises to provide a fast, inexpensive, and reliable method for routine beach surveying. Unmanned aerial vehicles (UAVs) are often successfully employed for SfM surveys but can be limited by poor weather ad government regulations, which can make flying difficult or impossible. To circumvent these limitations, a digital camera can be attached to a tall pole on a mobile platform to obtain aerial imagery, avoiding the restrictions of UAV flight. This thesis compares these two techniques of image acquisition for routine beach monitoring. Three surveys were conducted at monthly intervals on a beach on the central South Carolina coast, using both UAV and pole photogrammetry. While both methods use the same software and photogrammetric workflow, the UAV produced better results with far fewer processing artifacts compared to pole photogrammetry.Master of Science
Beach environments are vulnerable to extreme erosion, especially in the face of sea level rise and large storms like hurricanes. Monitoring erosion is a crucial part of a coastal management strategy, to mitigate risk to coastal hazards like extreme erosion, storm surge, and flooding. Erosion monitoring usually involves repeated elevation surveys to determine how much sand is being lost from the beach, and where that sand is being eroded away. Within the past decade, Structure from Motion (SfM) photogrammetry, the process of deriving ground elevation maps from multiple overlapping aerial photographs, has become a common technique for repeated elevation surveys. Unmanned aerial vehicles (UAVs) are often used to gather aerial imagery for SfM elevation surveys but are limited by poor weather conditions and government flight regulations, both of which can prohibit flight. However, similar aerial photographs can be taken with a camera mounted atop a tall pole, which can be used in wider range of weather conditions and without government regulations, providing an alternative when UAV flight is not an option. This study compares these two platforms for routine beach erosion monitoring surveys, evaluating them based on performance, cost, and feasibility. The UAV system is found to be fast, affordable, and effective, while the pole photogrammetry system is heavily affected by the slow speed of surveying and processing errors that make it unusable without significant improvement.
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Slaker, Brent. "Monitoring Underground Mine Displacement Using Photogrammetry and Laser Scanning." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51691.
Full textAbstract:
Photogrammetry and laser scanning are remote sensing technologies with the potential to monitor movements of rock masses and their support systems in underground mine environments. Displacements underground are traditionally measured through point measurement devices, such as extensometers. These are generally restricted to measuring one dimension, may change behavior with installation, may obstruct mining operations, and are restricted to monitoring the behavior of a small area. Photogrammetry and laser scanning offer the ability to monitor rock mass movements at millions of points in a local area, both accurately and quickly. An improved, or augmented, method for measuring displacements underground in a practical, cost-effective manner will lead to an improved understanding of rock mass behavior.
Several experiments were performed that demonstrate the applicability of these remote sensing techniques to monitoring rock mass changes. An underground mining environment presents unique challenges to using these tools for monitoring rock movements, such as: poor lighting, dust, fog, and unfavorable geometries. It is important, therefore, to demonstrate that these tools which have applications in other industries, can also be adapted to the conditions of an underground mine. The study sites chosen include two different underground limestone mines, two different underground coal mines, and the Mine Roof Simulator (MRS) at the Pittsburgh Office of Mine Safety and Health Research.
Both photogrammetry and laser scanning were tested at different limestone mines to detect scaling and spalling on ribs that occurred over several weeks. Both methods were successfully used to reconstruct three-dimensional models of the limestone ribs and detect areas of rock change between visits. By comparing the reconstructed point clouds, and the triangulated meshes created from them, volumes of rock change could be quantified. The laser scanned limestone mine showed a volume of 2.3 m3 and 2.6 m3 being displaced across two ribs between visits. The photogrammetry study involved seven different pillars and at least one rib face modeled on each, with volume changes of 0.29 to 4.03 m3 detected between visits. The rock displaced from the ribs could not be measured independently of the remote sensing, but a uniform absence of rock movement across large areas of the mine validates the accuracy of the point clouds. A similar test was performed using laser scanning in an underground coal mine, where the displacement was induced by removing material by hand from the ribs. Volume changes as small as 57 cm3, or slightly larger than a golf ball, and as large as 57,549 cm3, were detectable in this environment, despite the change in rib surface reflectance and mine geometry.
In addition to the rib displacement, photogrammetry was selected as a tool for monitoring standing supports in underground coal mines. The additional regulatory restrictions of underground coal may preclude the use of laser scanning in these mines where deformation is most likely to occur. The camera used for photogrammetry is ATEX certified as explosion proof and is indicative of the specifications that could be expected in an MSHA approved camera. Three different experiments were performed with this camera, including a laboratory controlled standing support deformation at the MRS and an in-mine time-lapse experiment measuring the response of a wooden crib and steel support to abutment loading. The experiment reconstructing a standing support in the MRS showed a cumulative convergence of 30.93 cm through photogrammetry and 30.48 cm as measured by the system. The standing support monitoring in the underground coal mine environment showed a steel support cumulative convergence of 1.10 cm, a wooden crib cumulative convergence of 0.62 cm, and a measured cumulative convergence on the wooden crib of 0.62 cm.
These techniques explored in this report are not intended to supplant, but rather supplement, existing measurement technologies. Both laser scanning and photogrammetry have physical and regulatory limitations in their application to measuring underground mine deformations, however, their ability to provide time-lapse three-dimensional measurements of entire mine sections is a strength difficult to emulate with traditional point measurement techniques. A fast, cost-effective, and practical application of remote sensing to monitoring mine displacements will improve awareness and understanding of rock mass behavior.Ph. D.
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Johnson, Theodore David. "The Sequential Givens method for adjustment computations in photogrammetry." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/44070.
Full textAbstract:
The Givens orthogonalization algorithm is an efficient alternative to the normal equations method for solving many adjustment problems in photogrammetry. The Givens method is one of a class of methods for solving linear systems known generally as orthogonalization or QR methods. It allows for sequential processing and greatly simplifies the computation of statistics on the observations and residuals. The underlying reason for these advantages is the immediate availability of the orthogonal Q matrix, which is computed as the data are processed and is intimately related to the statistics needed for blunder detection. One of these statistics, the F statistic computed from externally studentized residuals, is both easily obtained and well-suited for blunder detection.
The Givens method requires nearly four times the number of computations as compared to the normal equations approach in order to reach a solution. However, depending on the size of the problem, blunder detection through the normal equations requires far more computer time than is required when starting with a Givens decomposition.
The method allows a user to review intermediate results, test residuals and modify the solution without having to compute a full solution. Adjustments of a level net and a single-photo resection are used to demonstrate the method.
Because of the advantage in computational time, the Givens method is superior to the normal equations approach when rigorous blunder detection is required.Master of Science
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Slaker, Brent Allan. "Monitoring Underground Mine Displacement Using Photogrammetry and Laser Scanning." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/51691.
Full textAbstract:
Photogrammetry and laser scanning are remote sensing technologies with the potential to monitor movements of rock masses and their support systems in underground mine environments. Displacements underground are traditionally measured through point measurement devices, such as extensometers. These are generally restricted to measuring one dimension, may change behavior with installation, may obstruct mining operations, and are restricted to monitoring the behavior of a small area. Photogrammetry and laser scanning offer the ability to monitor rock mass movements at millions of points in a local area, both accurately and quickly. An improved, or augmented, method for measuring displacements underground in a practical, cost-effective manner will lead to an improved understanding of rock mass behavior.
Several experiments were performed that demonstrate the applicability of these remote sensing techniques to monitoring rock mass changes. An underground mining environment presents unique challenges to using these tools for monitoring rock movements, such as: poor lighting, dust, fog, and unfavorable geometries. It is important, therefore, to demonstrate that these tools which have applications in other industries, can also be adapted to the conditions of an underground mine. The study sites chosen include two different underground limestone mines, two different underground coal mines, and the Mine Roof Simulator (MRS) at the Pittsburgh Office of Mine Safety and Health Research.
Both photogrammetry and laser scanning were tested at different limestone mines to detect scaling and spalling on ribs that occurred over several weeks. Both methods were successfully used to reconstruct three-dimensional models of the limestone ribs and detect areas of rock change between visits. By comparing the reconstructed point clouds, and the triangulated meshes created from them, volumes of rock change could be quantified. The laser scanned limestone mine showed a volume of 2.3 m3 and 2.6 m3 being displaced across two ribs between visits. The photogrammetry study involved seven different pillars and at least one rib face modeled on each, with volume changes of 0.29 to 4.03 m3 detected between visits. The rock displaced from the ribs could not be measured independently of the remote sensing, but a uniform absence of rock movement across large areas of the mine validates the accuracy of the point clouds. A similar test was performed using laser scanning in an underground coal mine, where the displacement was induced by removing material by hand from the ribs. Volume changes as small as 57 cm3, or slightly larger than a golf ball, and as large as 57,549 cm3, were detectable in this environment, despite the change in rib surface reflectance and mine geometry.
In addition to the rib displacement, photogrammetry was selected as a tool for monitoring standing supports in underground coal mines. The additional regulatory restrictions of underground coal may preclude the use of laser scanning in these mines where deformation is most likely to occur. The camera used for photogrammetry is ATEX certified as explosion proof and is indicative of the specifications that could be expected in an MSHA approved camera. Three different experiments were performed with this camera, including a laboratory controlled standing support deformation at the MRS and an in-mine time-lapse experiment measuring the response of a wooden crib and steel support to abutment loading. The experiment reconstructing a standing support in the MRS showed a cumulative convergence of 30.93 cm through photogrammetry and 30.48 cm as measured by the system. The standing support monitoring in the underground coal mine environment showed a steel support cumulative convergence of 1.10 cm, a wooden crib cumulative convergence of 0.62 cm, and a measured cumulative convergence on the wooden crib of 0.62 cm.
These techniques explored in this report are not intended to supplant, but rather supplement, existing measurement technologies. Both laser scanning and photogrammetry have physical and regulatory limitations in their application to measuring underground mine deformations, however, their ability to provide time-lapse three-dimensional measurements of entire mine sections is a strength difficult to emulate with traditional point measurement techniques. A fast, cost-effective, and practical application of remote sensing to monitoring mine displacements will improve awareness and understanding of rock mass behavior.Ph. D.
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Dwaik, Fathi Y. "INS, GPS, and photogrammetry integration for vector gravimetry estimation /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487953204279825.
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Hill, Justin John Whatton. "A line photogrammetry algorithm for 3D rectilinear object reconstruction." Master's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/18309.
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This thesis introduces an alternative formulation for line photogrammetry. The aim was to develop and test a method of computing the position and orientation of a straight line in space using two or more oriented images of that line. The algorithm presented is intended for object reconstruction and is motivated by the need to reconstruct man-made objects in urban areas, such as buildings and the industrial inspection arena. The method aims to obtain a best-fit line through a "pencil of planes". The reconstructed 3D line is defined by two points as opposed to the conventional representation, which uses a point and a direction vector. The approach to this problem involves the calculation of a projection plane for each image containing the perspective centre and two transformed line-point observations in the image. A least squares adjustment involves fitting a straight line as near as possible to the projection planes from all images simultaneously. The adjusted line is referred to as a best-fitting line through a "pencil of planes" (POP). In this project, a mathematical model was formulated for the application of this concept. This algorithm was coded and tested on two cases. A set of scanned aerial images of a residential area with a scale of 1: 5000 provided the primary test case. Lines delineating three roofs visible in the aerial images were reconstructed using the POP method and compared with ground truth data. The lines reconstructed using the POP method were compared to those reconstructed using an existing method of line photogrammetry, proposed by Mulawa (1988). The second test was based on a set of close-range images captured using a small-format digital camera. Lines delineating the bars of a metal frame generally used as a precise control field for camera calibration, were reconstructed. In both test cases, X² tests were applied, and the standard deviations calculated. In the aerial case, standard deviations obtained were generally in the region of about 5cm. The ground resolution of the images was 7.Scm. In the close-range case the ground resolution was approximately 1.3mm, and the standard deviations obtained were generally of the order of 0.7mm. Of the lines computed, 84% of the adjustments passed the X² test. The results obtained confirmed that the POP algorithm is a practicable means of adjusting observations to obtain best-fitting 3D lines using observations made in a set of oriented images.
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Osterman, Fredrik. "Comparison of Photogrammetry Interpretation with Physical Structural Field Measurements." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324699.
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Fracture mapping of bedrock and knowledge about how fractures influence rock strength and stability is of great importance in a constructional context. These factors largely dictate where one can build and not build in rock, and to what extent reinforcements and safety measurements are needed. In a city like Stockholm where infrastructure has been forced to expand due to a rapidly growing population, this type of knowledge plays a central role to ensure continued development. Fracture mapping is traditionally executed by a geologist who manually measures fracture orientations with a compass. However, this method bears obvious risks as the geologist must physically approach a possibly unstable rock face to carry out manual measurements of fractures and structures. In some cases, the geologist is not even allowed to approach the rock face for safety reasons. The aspect of time should not be neglected either since the process of manual measurements is often time consuming. This has resulted in newer and safer technological methods being developed and tested. In 2015, The Geological Survey of Sweden (SGU) acquired photogrammetrical equipment and 3D-modelling software ShapeMetriX to ease the fracture mapping process, obtain data of higher quality and increase personnel safety in the field. In this report, the photogrammetrical system is quality tested by comparing its results with manual field measurements. The control was carried out on three different rock faces in two locations; Torsgatan, a central street in Stockholm, and Kungens kurva, a construction site southwest of central Stockholm. The study shows that the results of ShapeMetriX correspond well to the manual field measurements and that the method has several advantages as well as disadvantages compared to conventional mapping methods.Sprickkartering av berggrund och kunskap om hur bergets hållfasthet och stabilitet påverkas av sprickor är viktigt i konstruktionssammanhang. Dessa faktorer dikterar till stor del var man kan och inte kan bygga i berg samt till vilken grad förstärkningar och säkerhetsåtgärder behövs. I en stad lik Stockholm vars infrastruktur tvingas anpassa sig efter en kraftigt växande befolkning sätts dessa kunskaper i en ännu mer central roll för att kunna säkerställa stadens fortsatta utveckling. Sprickkartering utförs traditionellt av en geolog som med hjälp av en kompass manuellt mäter sprickors orientering. Detta medför dock uppenbara risker då denna fysiskt måste befinna sig nära bergskärningen för att kunna utföra mätningar av sprickor och strukturer. I vissa fall kan geologen, av säkerhetsskäl, inte alls närma sig den berörda ytan vilket omöjliggör en detaljerad kartering. Tidsaspekten av det hela bör inte heller bortses då manuella fältmätningar ofta är tidskrävande. Detta har resulterat i att nyare och säkrare teknologiska metoder för kartering och klassificering av berg både utvecklas och prövas. Sveriges geologiska undersökning (SGU) förvärvade 2015 fotogrammetrisk karteringsutrustning och 3D-modelleringsprogrammet ShapeMetriX för att effektivisera sprickkarteringsarbetet, erhålla data med högre kvalitét och öka säkerheten för personal I fält. I denna rapport utvärderas nämnda stereofotogrammetriska karteringsmetod med tillhörande analysmjukvara genom en jämförelse av dess resultat med manuella fältmätningar. Kontrollen utfördes på tre berghällar; en belägen på Torsgatan, en central gågata strax nordväst om centrala Stockholm och de andra vid Kungens kurva, en byggarbetsplats i närheten av Skärholmen i södra Stockholm. Resultat av studien visar att ShapeMetriX mätningar väl stämmer överens med manuella fältmätningar och även att metoden har en
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Alshawabkeh, Yahya. "Integration of laser scanning and photogrammetry for heritage documentation." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28994.
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Dietrich, James. "Applications of Structure-from-Motion Photogrammetry to Fluvial Geomorphology." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/18701.
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Since 2011, Structure-from-Motion Multi-View Stereo Photogrammetry (SfM or SfM-MVS) has gone from an overlooked computer vision technique to an emerging methodology for collecting low-cost, high spatial resolution three-dimensional data for topographic or surface modeling in many academic fields. This dissertation examines the applications of SfM to the field of fluvial geomorphology. My research objectives for this dissertation were to determine the error and uncertainty that are inherent in SfM datasets, the use of SfM to map and monitor geomorphic change in a small river restoration project, and the use of SfM to map and extract data to examine multi-scale geomorphic patterns for 32 kilometers of the Middle Fork John Day River. SfM provides extremely consistent results, although there are systematic errors that result from certain survey patterns that need to be accounted for in future applications. Monitoring change on small restoration stream channels with SfM gave a more complete spatial perspective than traditional cross sections on small-scale geomorphic change. Helicopter-based SfM was an excellent platform for low-cost, large scale fluvial remote sensing, and the data extracted from the imagery provided multi-scalar perspectives of downstream patterns of channel morphology. This dissertation makes many recommendations for better and more efficient SfM surveys at all of the spatial scales surveyed. By implementing the improvements laid out here and by other authors, SfM will be a powerful tool that will make 3D data collection more accessible to the wider geomorphic community.
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Maier, Kathrin. "Direct multispectral photogrammetry for UAV-based snow depth measurements." Thesis, KTH, Geoinformatik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254566.
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Due to the changing climate and inherent atypically occurring meteorological events in the Arctic regions, more accurate snow quality predictions are needed in order to support the Sámi reindeer herding communities in northern Sweden that struggle to adapt to the rapidly changing Arctic climate. Spatial snow depth distribution is a crucial parameter not only to assess snow quality but also for multiple environmental research and social land use purposes. This contrasts with the current availability of affordable and efficient snow monitoring methods to estimate such an extremely variable parameter in both space and time. In this thesis, a novel approach to determine spatial snow depth distribution in challenging alpine terrain is presented and tested during a field campaign performed in Tarfala, Sweden in April 2019. A multispectral camera capturing five spectral bands in wavelengths between 470 and 860 nanometers on board of a small Unmanned Aerial Vehicle is deployed to derive 3D snow surface models via photogrammetric image processing techniques. The main advantage over conventional photogrammetric surveys is the utilization of accurate RTK positioning technology that enables direct georeferencing of the images, and thus eliminates the need for ground control points and dangerous and time-consuming fieldwork. The continuous snow depth distribution is retrieved by differencing two digital surface models corresponding to the snow-free and snow-covered study areas. An extensive error assessment based on ground measurements is performed including an analysis of the impact of multispectral imagery. Uncertainties and non-transparencies due to a black-box environment in the photogrammetric processing are, however, present, but accounted for during the error source analysis. The results of this project demonstrate that the proposed methodology is capable of producing high-resolution 3D snow-covered surface models (< 7 cm/pixel) of alpine areas up to 8 hectares in a fast, reliable and cost-efficient way. The overall RMSE of the snow depth estimates is 7.5 cm for data acquired in ideal survey conditions. The proposed method furthermore assists in closing the scale gap between discrete point measurements and regional-scale remote sensing, and in complementing large-scale remote sensing data by providing an adequate validation source. As part of the Swedish cooperation project ’Snow4all’, the findings of this project are used to support and validate large-scale snow models for improved snow quality prediction in northern Sweden.På grund av klimatförändringar och naturliga meteorologiska händelser i arktis behövs mer exakta snökvalitetsprognoser för att stödja samernas rensköttsamhällen i norra Sverige som har problem med att anpassa sig till det snabbt föränderliga arktiska klimatet. Rumslig snödjupsfördelning är en avgörande parameter för att inte bara bedöma snökvaliteten utan även för flera miljöforskning och sociala markanvändningsändamål. Detta står i motsats till den nuvarande tillgången till överkomliga och effektiva metoder för snöövervakning för att uppskatta sådan extremt varierande parameter i tid och rum. I detta arbete presenteras och testas en ny metod för att bestämma rumslig snödjupssdistribution i utmanande alpin terräng under en fältstudie som genomfördes i Tarfala i norra Sverige i april 2019. Via fotogrammetrisk bildbehandlingsteknik hämtades snöytemodeller i 3D med hjälp av en multispektral kamera monterad på en liten obemannad drönare. En viktig fördel, i jämförelse med konventionella fotogrammetriska undersökningar, är användningen av exakt RTK-positioneringsteknik som möjliggör direkt georeferencing och eliminerar behovet av markkontrollpunkter. Den kontinuerliga snödjupfördelningen hämtas genom att ytmodellerna delas upp i snöfria respektive snötäckta undersökningsområden. En omfattande felsökning som baseras på markmätningar utförs, inklusive en analys av effekten av multispektrala bilder. Resultaten från denna studie visar att den famtagna metoden kan producera högupplösta snötäckta höjdmodeller i 3D (< 7 cm/pixel) av alpina områden på upp till 8 hektar på ett snabbt, pålitligt och kostnadseffektivt sätt. Den övergripande RMSE för det beräknade snödjupet är 7,5 cm för data som förvärvats under idealiska undersökningsförhållanden. Som ett led i det svenska projektet “Snow4all” används resultaten från projektet för att förbättra och validera storskaliga snömodeller för att bättre förutse snökvaliteten i norra Sverige.
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Givens, Matthew. "Multiple IMU Sensor Fusion for SUAS Navigation and Photogrammetry." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7617.
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Inertial measurement units (IMUs) are devices that sense accelerations and angular rates in 3D so that vehicles and other devices can estimate their orientations, positions, and velocities. While traditionally large, heavy, and costly, using mechanical gyroscopes and stabilized platforms, the recent development of micro-electromechanical sensor (MEMS) IMUs that are small, light, and inexpensive has led to their adoption in many everyday systems such as cell phones, video game controllers, and commercial drones. MEMS IMUs, despite their advantages, have major drawbacks when it comes to accuracy and reliability. The idea of using more than one of these sensors in an array, instead of using only one, and fusing their outputs to generate an improved solution is explored in this thesis.
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ES, SEBAR LEILA. "Metrology for Cultural Heritage: multispectral 3D models by photogrammetry." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2959961.
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Gyftakis, Sotirios. "Image-based Change Detection of Geospatial Objects Using Positional Uncertainty." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/GyftakisS2005.pdf.
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Ahmed, Kamal. "Robustified least squares solutions for monitoring deformation of structures /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/10102.
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Hsia, Jung-Sheng. "A new method for the automated production of digital terrain models using a combination of feature points, grid points and filling back points." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337379.
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Teng, Chee Hua. "Object recognition in aerial imagery assisted by GIS for topographic dataset revision." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310168.
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Meneguette, Arlete Aparecida Correia. "Cartographic accuracy and information content of space imagery for digital map compilation and map revision." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295491.
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Neto, Francelina M. M. A. "Analysis of the characteristics and orientation of linear array stereo imagery from satellite sensors." Thesis, University College London (University of London), 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320524.
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Smit, Julian Lloyd. "Three dimensional measurement of textured surfaces using digital photogrammetric techniques." Doctoral thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/16087.
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Bibliography: pages 133-156.The deep-level gold mines on the Witwatersrand (South Africa) are located at depths of over 3,000m below surface. Mining excavations follow tabular reefs that are kilometres in extent, but only a few centimetres thick. Due to the great depths of these excavations and the large overburden of rock, immense pressure is exerted on the rock mass being excavated. In order to relieve this stress in the rock mass being mined, the rock is "pre-conditioned" by pre-fracturing the rock face with large blasts. This has the effect of pushing the critical stress load further into the rock mass, thus increasing safety at the rock face. To better understand the rock behaviour as a result of by pre-conditioning blasts, it is desirable to quantify the deformations of the rock face. Digital photogrammetry provides an ideally suited method of monitoring these deformations, as the necessary equipment is portable and easy to use underground, where the conditions are extreme with temperatures approaching 40°C and humidity levels close to 100%. Digital photogrammetric techniques are also highly accurate, and can be used to detect relatively small three-dimensional movements. The determination of the three-dimensional (XYZ) co-ordinates of the rock face, represented by densely spaced individual points, by means of digital photogrammetric techniques, is reported in this thesis. The novel measurement system developed comprises the following components: * establishment of a stable reference co-ordinate system; * image acquisition; * camera calibration and exterior orientation calculation; * feature extraction; * multi-image matching and space intersection; and * surface modelling. The details of the techniques developed and implemented in order to generate the necessary object space co-ordinates are discussed. Sub-millimetre accuracy point determination, as required for deformation analysis was achieved and a sample of the underground test result data is presented. The final analysis of the underground test data made it apparent that digital photogrammetry is highly suitable for the determination of digital terrain models of the rock surfaces, for subsequent deformation analysis. The relative speed of the process and the convenient size of the equipment makes the technology especially suitable to the demanding underground mining environment. The difficulties, which were experienced as a result of the highly restrictive environment, were overcome through careful planning and pre-analysis. It can thus be concluded that this approach is not only feasible, but it meets the stringent demands of the underground mining industry, as is confirmed by the high accuracy of the final surface point co-ordinates achieved. In addition to being implemented in the underground mining industry, the measurement system developed was used for the mapping of several other textured surfaces. In particular it was used in mapping the 3.6 million-year-old hominid trackway located at Laetoli (Tanzania), the imprints of cheetah and rhinoceros for the purposes of conservation, and for the archaeological documentation of a shipwreck found off the Cape coast (South Africa). All of these applications are discussed and the results achieved presented.
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Dingle, Malcolm Robert. "Determining the parameters of cylinders using digital photogrammetry for application to pipe measurement in industrial plants." Doctoral thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/17545.
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Bibliography: p.187-193.The maintenance and expansion of piping systems of petro-chemical plants is a complex and costly process. These costs can be reduced by knowledge of the as-built dimensions and layout of the piping system. As-built Computer Aided Design (CAD) models of such piping systems, specifically the use of Plant Design System (PDS) software packages, allow for more efficient planning than paper plans. Conventional surveying and analogue photogrammetry have been methods that have traditionally been used to capture the necessary CAD information. More recently, the Department of Geomatics at the University of Cape Town has produced software which replicates the analogue photogrammetric approach using digital images (Cammidge, 1996). The objective of this thesis is to develop a pipe measurement technique which can supplement those currently being used and overcome some of their shortcomings. A further objective is to present an overview of the pipe measurement techniques, photogrammetric principles, image processing techniques and programming considerations which would be required to develop a robust, fully functional, pipe measurement software package integrated with a PDS. The author hopes that this thesis will form the foundation for the development of such a software package for local and possibly international industry. A digital photogrammetric technique related to line photogrammetry is developed. This technique makes use of lines in an image which represent the silhouette edges of the cylinder. The use of photogrammetry based on lines avoids some of the shortcomings of conventional point-based photogrammetry. It is not necessary to identify conjugate points in images, nor is it even necessary for overlapping images of the cylinder to be captured. Furthermore, this thesis reports on a number of tests designed to gauge the developed techniques' accuracy and suitability for use in pipe metrology in an industrial plant. The techniques were found to be capable of achieving results which deviated by, on average, 2-3mm in object position and 0.1° in direction from the likely true values of the cylinder axis. The radius could be determined to better than 1 mm. The techniques developed here proved to be suitably accurate for the purpose of determining the parameters of pipes in industrial plants. However, certain factors may reduce the accuracy and these are also discussed. This thesis concludes that a novel digital photogrammetric technique for measuring pipes in an industrial plant was successfully developed. Recommendations are made as to how the technique might be improved to allow sub-millimetre accuracies to be obtained. Finally, a recommendation is made that the information contained within the thesis be used as the basis for designing a digital photogrammetric measurement module to be linked to a PDS.
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Van, der Vlugt Graeme. "Algorithms and design aspects of an automated vision based 3-D surface measurement system." Doctoral thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/15943.
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Bibliography: pages 122-132.This thesis reports on the investigation, development and implementation of digital/photogrammetric algorithms into a compatible system for measuring surfaces. Each of the important stages of such a measurement are dealt with in the text. Specifically, these include camera calibration, free network adjustment, location and centering of circular targets, orientation determination, the matching and measuring process and handling of results. The chosen algorithms (existing, modified and/or developed in this work) were all incorporated/designed to form an efficient and usable surface measurement system. Of particular importance was the investigation of determining conjugate (matching) surface points in the multiple images. In this respect a novel multi-image correlation search procedure was designed, implemented and tested. This algorithm provides high accuracy matching methods with suitably close provisional matching positions. A series of tests was carried out to study the performance of the algorithm and the results are presented in this work. Most notable was the method's high reliability when using more than two images, even in image areas with highly repetitive patterns. Multi-image correlation is considerably more robust than "traditional" stereo-correlation procedures. Other system tests performed included: tests on the stability of projected light from two off-the shelf projection devices; a test on the effect of PLL synchronisation of the camera-framegrabber combination of the images; tests on the accuracy performance of different centering techniques and surface measurements themselves. It was found that the off-the-shelf slide projector tested did not provide a stable projection, however an overhead projector which was warmed up for over an hour provided a suitably stable projection. The PLL synchronisation of the camera-framegrabber system produced a noticeable line-jitter (between sequential images) reaching over 0.1 pixels in the most badly affected lines. In a simulated test with artificial targets, template matching obtained the most accurate centre coordinates, however the much faster weighted centre of gravity with grey value as weight technique also provides highly accurate results. These two centering techniques agreed to 1/100th of a pixel when centering with real targets. The much faster centroiding technique is thus highly recommended for any application which requires high processing speeds (such as with on-line systems). Surface measurement precisions of 5/100th mm in the plane of the surface and 15/100th mm in depth were achieved in the measurements of the test objects. These objects all had similar dimensions with a diagonal of about 250mm in length. These accuracies could be substantially improved with higher resolution cameras and more images. Together, the algorithms presented in this work formed a surface measurement software program. The success of many of these algorithms, such as the target location method, and the semi-automatic point identification and exterior orientation determination procedure, could not be gauged with results as such, but by their successful incorporation into the system as properly functioning units.
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Davey, Justin John. "Object reconstruction using close-range all-round digital photogrammetry for applications in industry." Master's thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/17544.
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Bibliography: p. 66-68.Photogrammetry has many inherent advantages in engineering and industrial applications, which include the ability to obtain accurate, non-contact measurements from data rapidly acquired with the object in situ. Along with these advantages, digital photogrammetry offers the potential for the automation or semi-automation of many of the conventional photogrammetric procedures, leading to real-time or near real-time measurement capabilities. However, all-round surface measurement of an object usually benefits less from the above advantages of photogrammetry. To obtain the necessary imagery from all sides of the measurement object, real-time processing is nearly impossible, and it becomes difficult to avoid moving the object, thus precluding in situ measurement. However, all-round digital photogrammetry and, in particular, the procedure presented here, still offer advantages over other methods of full surface measurement, including rapid, non-contact data acquisition along with the ability to store and reprocess data at a later date. Conventional or topographic photogrammetry is well-established as a tool for mapping simple terrain surfaces and for acquiring accurate 3-D point data. The complexities of all-round photogrammetry make many of the standard photogrammetric methods all but redundant. The work presented in this thesis was aimed at the development of a reliable method of obtaining complete surface data of an object with non-topographic, all-round, close-range digital photogrammetry. A method was developed to improve the integrity of the data, and possibilities for the presentation and visualisation of the data were explored. The potential for automation was considered important, as was the need to keep the overall time required to a minimum. A measurement system was developed to take as input an object, and produce as output an accurate, representative point cloud, allowing for the reconstruction of the surface. This system included the following procedures: ■ a novel technique of achieving high-accuracy system pre-calibration using a cubic control frame and fixed camera stations, ■ separate image capture for the control frame and the object, ■ surface sub-division and all-round step-wise image matching to produce a comprehensive 3-D data set, ■ point cloud refinement, and ■ surface reconstruction by separate surface generation. The development and reliability of these new approaches is discussed and investigated; and the results of various test procedures are presented. The technique of system pre-calibration involved the use of a mechanical device - a rotary table - to impart precisely repeatable rotations to the control frame and, separately, the object. The actual repeatability precision was tested and excellent results achieved, with standard deviations for the resected camera station coordinates of between 0.05 and 0.5 mm. In a detailed test case, actual rotations differed from the desired rotations by an average of 0.7" with a standard deviation of less than 2'. The image matching for the test case, from a set of forty-eight images, achieved a satisfactory final accuracy, comparable to that achieved in other similar work. The meaningful reconstruction of surfaces presented problems, although an acceptable rendering was achieved, and a thorough survey of current commercially available software failed to produce a package capable of all-round modelling from random 3-D data. The final analysis of the results indicated that digital photogrammetry, and this method in particular, are highly suited to accurate all-round surface measurement. The potential for automation - and, therefore, for near real-time results - of the method in the stages of image acquisition and processing, calibration, image matching and data visualisation is great. The method thus lends itself to industrial applications. However, the need for a robust and rapid method of surface reconstruction needs to be fulfilled.
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Calitz, Michaelangelo Franco. "Image understanding and feature extraction for applications in industry and mapping." Doctoral thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/15942.
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Bibliography: p. 212-220.The aim of digital photogrammetry is the automated extraction and classification of the three dimensional information of a scene from a number of images. Existing photogrammetric systems are semi-automatic requiring manual editing and control, and have very limited domains of application so that image understanding capabilities are left to the user. Among the most important steps in a fully integrated system are the extraction of features suitable for matching, the establishment of the correspondence between matching points and object classification. The following study attempts to explore the applicability of pattern recognition concepts in conjunction with existing area-based methods, feature-based techniques and other approaches used in computer vision in order to increase the level of automation and as a general alternative and addition to existing methods. As an illustration of the pattern recognition approach examples of industrial applications are given. The underlying method is then extended to the identification of objects in aerial images of urban scenes and to the location of targets in close-range photogrammetric applications. Various moment-based techniques are considered as pattern classifiers including geometric invariant moments, Legendre moments, Zernike moments and pseudo-Zernike moments. Two-dimensional Fourier transforms are also considered as pattern classifiers. The suitability of these techniques is assessed. These are then applied as object locators and as feature extractors or interest operators. Additionally the use of fractal dimension to segment natural scenes for regional classification in order to limit the search space for particular objects is considered. The pattern recognition techniques require considerable preprocessing of images. The various image processing techniques required are explained where needed. Extracted feature points are matched using relaxation based techniques in conjunction with area-based methods to 'obtain subpixel accuracy. A subpixel pattern recognition based method is also proposed and an investigation into improved area-based subpixel matching methods is undertaken. An algorithm for determining relative orientation parameters incorporating the epipolar line constraint is investigated and compared with a standard relative orientation algorithm. In conclusion a basic system that can be automated based on some novel techniques in conjunction with existing methods is described and implemented in a mapping application. This system could be largely automated with suitably powerful computers.
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Madani, Mostafa S. "Accuracy potential of non-metric cameras in close-range photogrammetry /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487327695623993.
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