Visual Techniques for Geological Fieldwork Using Mobile Devices

Visual techniques in general and 3D visualisation in particular have seen considerable adoption within the last 30 years in the geosciences and geology. Techniques such as volume visualisation, for analysing subsurface processes, and photo-coloured LiDAR point-based rendering, to digitally explore rock exposures at the earth’s surface, were applied within geology as one of the first adopting branches of science. A large amount of digital, geological surface- and volume data is nowadays available to desktop-based workflows for geological applications such as hydrocarbon reservoir exploration, groundwater modelling, CO2 sequestration and, in the future, geothermal energy planning. On the other hand, the analysis and data collection during fieldwork has yet to embrace this ”digital revolution”: sedimentary logs, geological maps and stratigraphic sketches are still captured in each geologist’s individual fieldbook, and physical rocks samples are still transported to the lab for subsequent analysis. Is this still necessary, or are there extended digital means of data collection and exploration in the field ? Are modern digital interpretation techniques accurate and intuitive enough to relevantly support fieldwork in geology and other geoscience disciplines ? This dissertation aims to address these questions and, by doing so, close the technological gap between geological fieldwork and office workflows in geology. The emergence of mobile devices and their vast array of physical sensors, combined with touch-based user interfaces, high-resolution screens and digital cameras provide a possible digital platform that can be used by field geologists. Their ubiquitous availability increases the chances to adopt digital workflows in the field without additional, expensive equipment. The use of 3D data on mobile devices in the field is furthered by the availability of 3D digital outcrop models and the increasing ease of their acquisition. This dissertation assesses the prospects of adopting 3D visual techniques and mobile devices within field geology. The research of this dissertation uses previously acquired and processed digital outcrop models in the form of textured surfaces from optical remote sensing and photogrammetry. The scientific papers in this thesis present visual techniques and algorithms to map outcrop photographs in the field directly onto the surface models. Automatic mapping allows the projection of photo interpretations of stratigraphy and sedimentary facies on the 3D textured surface while providing the domain expert with simple-touse, intuitive tools for the photo interpretation itself. The developed visual approach, combining insight from all across the computer sciences dealing with visual information, merits into the mobile device Geological Registration and Interpretation Toolset (GRIT) app, which is assessed on an outcrop analogue study of the Saltwick Formation exposed at Whitby, North Yorkshire, UK. Although being applicable to a diversity of study scenarios within petroleum geology and the geosciences, the particular target application of the visual techniques is to easily provide field-based outcrop interpretations for subsequent construction of training images for multiple point statistics reservoir modelling, as envisaged within the VOM2MPS project. Despite the success and applicability of the visual approach, numerous drawbacks and probable future extensions are discussed in the thesis based on the conducted studies. Apart from elaborating on more obvious limitations originating from the use of mobile devices and their limited computing capabilities and sensor accuracies, a major contribution of this thesis is the careful analysis of conceptual drawbacks of established procedures in modelling, representing, constructing and disseminating the available surface geometry. A more mathematically-accurate geometric description of the underlying algebraic surfaces yields improvements and future applications unaddressed within the literature of geology and the computational geosciences to this date. Also, future extensions to the visual techniques proposed in this thesis allow for expanded analysis, 3D exploration and improved geological subsurface modelling in general.publishedVersio

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

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

Estimating Carbon Pool and Carbon Release due to Tropical Deforestation Using High-resolution Satellite Data: Carbon Release due to Tropical Deforestation

Forest-cover in the tropics is changing rapidly due to indiscriminate removal of timber from many localities. The main focus of the study is to develop an operational tool for monitoring biomass and carbon pool of tropical forest ecosystems. The method was applied to a test site of Bangladesh. The research used Landsat ETM+, Landsat TM and IRS pan images of 2001, 1992 and 1999 respectively. Geometrically corrected Landsat ETM+ imagery was obtained from USGS and adjusted to the field using GPS. Historical images were corrected using image-to-image registration. Atmospheric correction was done by modified dark object subtraction method. Stratified sampling design based on the remote sensing image was applied for assessing the above-ground biomass and carbon content of the study area. Field sampling was done during 2002-2003. Dbh and height of all the trees inside the sample plots were measured. Field measurement was finally converted to carbon content using allometric relations. Three different methods: stratification, regression and k-nearest neighbors were tested for combining remote sensing image information and field-based terrestrial carbon pool. Additional field sampling was conducted during 2003-2004 for testing the accuracy. Finally regression method was selected. The amount of carbon released and sequestrated from the ecosystem was estimated. The application of the developed method would be quite useful for understating the terrestrial carbon dynamics and global climate change

GIS como ferramenta de ajuda pré- e pós-processamento de modelos hidrodinâmicos. Aplicação ao estuário do Guadiana

Dissertação de mest., Geomática (Análise de Sistemas Ambientais), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2013The main objective of this work is to develop GIS based techniques to aid the setup of hydrodynamic models and to improve model results. This dissertation analyzes well-known GIS methods and proposes new ones to prepare and process estuarine model data. Estuarine hydrodynamic models require management of large quantities of georeferenced information. A Geographic Information System (GIS) can help to store, manage, analyze and display all these data during the input and the output phases. The hydrodynamics of the Guadiana Estuary was simulated using a 2D configuration in MOHID Water Modelling System, based on a boundary fitted curvilinear grid. GIS tools were used to pre-process the model grid and bathymetry. The water domain was extracted from the orthophoto using unsupervised classification of the image based on principal component analysis of the spectral bands. The large amount of bathymetric measurement points was decreased using a spatial regular pattern (hexagons). The missing bathymetry data in some very shallow parts of the estuary were estimated from the orthophoto using correlation between existing data and spectral band values. The bathymetry data were interpolated into curvilinear grids by several different methods, including an advanced method using river straightening (transformation to the along-channel coordinate system). The finite volume model MOHID was used to test these methods and evaluate the associated improvements. The model results were in good agreement with the observations under well-mixed conditions. Including the bathymetry estimated from orthophoto improved the accuracy of the simulations; and using advanced interpolation methods improved the results even more. The bathymetry interpolation in the channel-oriented coordinates significantly improved the direction of the water current. Good quality of the spatial input data was critical for obtaining good model results. The use of GIS tools to produce model inputs proved to be a valuable aid to coastal hydrodynamic modelling increasing substantially the model accuracy. This dissertation is useful in both theoretical and practical fields of science: in theoretical, by analyzing and developing GIS methods to prepare and process estuarine hydrodynamic model data, in practical, by creating an improved model setup for the Guadiana Estuary, using more accurate bathymetric data and a new curvilinear grid, thus obtaining more realistic results

Air Force Institute of Technology Research Report 2003

This report summarizes the research activities of the Air Force Institute of Technology’s Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, and Engineering Physics

The Segmentation of Reflectances from Moderate Resolution Remote Sensing Data for the Retrieval of Land Cover Specific Leaf Area Index

A method is developed to incorporate prior fuzzy knowledge about reflectance behavior of land cover types into the segmentation of reflectances from moderate scale remote sensing data. The procedure is applied to aggregated Landsat TM data and to MODIS data and used to derive land cover type specific leaf area index

Digital Restoration of Damaged Historical Parchment

In this thesis we describe the development of a pipeline for digitally restoring damaged historical parchment. The work was carried out in collaboration with London Metropolitan Archives (LMA), who are in possession of an extremely valuable 17th century document called The Great Parchment Book. This book served as the focus of our project and throughout this thesis we demonstrate our methods on its folios. Our aim was to expose the content of the book in a legible form so that it can be properly catalogued and studied. Our approach begins by acquiring an accurate digitisation of the pages. We have developed our own 3D reconstruction pipeline detailed in Chapter 5 in which each parchment is imaged using a hand-held digital-SLR camera, and the resulting image set is used to generate a high-resolution textured 3D reconstruction of each parchment. Investigation into methods for flatting the parchments demonstrated an analogy with surface parametrization. Flattening the entire parchment globally with various existing parametrization algorithms is problematic, as discussed in Chapters 4, 6, and 7, since this approach is blind to the distortion undergone by the parchment. We propose two complementary approaches to deal with this issue. Firstly, exploiting the fact that a reader will only ever inspect a small area of the folio at a given time, we proposed a method for performing local undistortion of the parchments inside an interactive viewer application. The application, described in Chapter 6, allows a user to browse a parchment folio as the application un-distorts in real-time the area of the parchment currently under inspection. It also allows the user to refer back to the original image set of the parchment to help with resolving ambiguities in the reconstruction and to deal with issues of provenance. Secondly, we proposed a method for estimating the actual deformation undergone by each parchment when it was damaged by using cues in the text. Since the text was originally written in straight lines and in a roughly uniform script size, we can detect the the variation in text orientation and size and use this information to estimate the deformation. in Chapter 7 we then show how this deformation can be inverted by posing the problem as a Poisson mesh deformation, and solving it in a way that guarantees local injectivity, to generate a globally flattened and undistorted image of each folio. We also show how these images can optionally be colour corrected to remove the shading cues baked into the reconstruction texture, and the discolourations in the parchment itself, to further improve legibility and give a more complete impression that the parchment has been restored. The methods we have developed have been very well received by London Metropolitan Archives, as well the the larger archival community. We have used the methods to digitise the entire Great Parchment Book, and have demonstrated our global flattening method on eight folios. As of the time of writing of this thesis, our methods are being used to virtually restore all of the remaining folios of the Great Parchment Book. Staff at LMA are also investigating potential future directions by experimenting with other interesting documents in their collections, and are exploring the possibility of setting up a service which would give access to our methods to other archival institutions with similarly damaged documents

Graduate School of Engineering and Management Catalog 2018-2019

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication

Morphology-based landslide monitoring with an unmanned aerial vehicle

PhD ThesisLandslides represent major natural phenomena with often disastrous consequences. Monitoring landslides with time-series surface observations can help mitigate such hazards. Unmanned aerial vehicles (UAVs) employing compact digital cameras, and in conjunction with Structure-from-Motion (SfM) and modern Multi-View Stereo (MVS) image matching approaches, have become commonplace in the geoscience research community. These methods offer a relatively low-cost and flexible solution for many geomorphological applications. The SfM-MVS pipeline has expedited the generation of digital elevation models at high spatio-temporal resolution. Conventionally ground control points (GCPs) are required for co-registration. This task is often expensive and impracticable considering hazardous terrain. This research has developed a strategy for processing UAV visible wavelength imagery that can provide multi-temporal surface morphological information for landslide monitoring, in an attempt to overcome the reliance on GCPs. This morphological-based strategy applies the attribute of curvature in combination with the scale-invariant feature transform algorithm, to generate pseudo GCPs. Openness is applied to extract relatively stable regions whereby pseudo GCPs are selected. Image cross-correlation functions integrated with openness and slope are employed to track landslide motion with subsequent elevation differences and planimetric surface displacements produced. Accuracy assessment evaluates unresolved biases with the aid of benchmark datasets. This approach was tested in the UK, in two sites, first in Sandford with artificial surface change and then in an active landslide at Hollin Hill. In Sandford, the strategy detected a ±0.120 m 3D surface change from three-epoch SfM-MVS products derived from a consumer-grade UAV. For the Hollin Hill landslide six-epoch datasets spanning an eighteen-month duration period were used, providing a ± 0.221 m minimum change. Annual displacement rates of dm-level were estimated with optimal results over winter periods. Levels of accuracy and spatial resolution comparable to previous studies demonstrated the potential of the morphology-based strategy for a time-efficient and cost-effective monitoring at inaccessible areas

Image Registration Workshop Proceedings

Automatic image registration has often been considered as a preliminary step for higher-level processing, such as object recognition or data fusion. But with the unprecedented amounts of data which are being and will continue to be generated by newly developed sensors, the very topic of automatic image registration has become and important research topic. This workshop presents a collection of very high quality work which has been grouped in four main areas: (1) theoretical aspects of image registration; (2) applications to satellite imagery; (3) applications to medical imagery; and (4) image registration for computer vision research