Mapping three-dimensional geological features from remotely-sensed images and digital elevation models.

Accurate mapping of geological structures is important in numerous applications, ranging from mineral exploration through to hydrogeological modelling. Remotely sensed data can provide synoptic views of study areas enabling mapping of geological units within the area. Structural information may be derived from such data using standard manual photo-geologic interpretation techniques, although these are often inaccurate and incomplete. The aim of this thesis is, therefore, to compile a suite of automated and interactive computer-based analysis routines, designed to help a the user map geological structure. These are examined and integrated in the context of an expert system. The data used in this study include Digital Elevation Model (DEM) and Airborne Thematic Mapper images, both with a spatial resolution of 5m, for a 5 x 5 km area surrounding Llyn Cow lyd, Snowdonia, North Wales. The geology of this area comprises folded and faulted Ordo vician sediments intruded throughout by dolerite sills, providing a stringent test for the automated and semi-automated procedures. The DEM is used to highlight geomorphological features which may represent surface expressions of the sub-surface geology. The DEM is created from digitized contours, for which kriging is found to provide the best interpolation routine, based on a number of quantitative measures. Lambertian shading and the creation of slope and change of slope datasets are shown to provide the most successful enhancement of DEMs, in terms of highlighting a range of key geomorphological features. The digital image data are used to identify rock outcrops as well as lithologically controlled features in the land cover. To this end, a series of standard spectral enhancements of the images is examined. In this respect, the least correlated 3 band composite and a principal component composite are shown to give the best visual discrimination of geological and vegetation cover types. Automatic edge detection (followed by line thinning and extraction) and manual interpretation techniques are used to identify a set of 'geological primitives' (linear or arc features representing lithological boundaries) within these data. Inclusion of the DEM data provides the three-dimensional co-ordinates of these primitives enabling a least-squares fit to be employed to calculate dip and strike values, based, initially, on the assumption of a simple, linearly dipping structural model. A very large number of scene 'primitives' is identified using these procedures, only some of which have geological significance. Knowledge-based rules are therefore used to identify the relevant. For example, rules are developed to identify lake edges, forest boundaries, forest tracks, rock-vegetation boundaries, and areas of geomorphological interest. Confidence in the geological significance of some of the geological primitives is increased where they are found independently in both the DEM and remotely sensed data. The dip and strike values derived in this way are compared to information taken from the published geological map for this area, as well as measurements taken in the field. Many results are shown to correspond closely to those taken from the map and in the field, with an error of < 1°. These data and rules are incorporated into an expert system which, initially, produces a simple model of the geological structure. The system also provides a graphical user interface for manual control and interpretation, where necessary. Although the system currently only allows a relatively simple structural model (linearly dipping with faulting), in the future it will be possible to extend the system to model more complex features, such as anticlines, synclines, thrusts, nappes, and igneous intrusions

Modeling and Simulation in Engineering

This book provides an open platform to establish and share knowledge developed by scholars, scientists, and engineers from all over the world, about various applications of the modeling and simulation in the design process of products, in various engineering fields. The book consists of 12 chapters arranged in two sections (3D Modeling and Virtual Prototyping), reflecting the multidimensionality of applications related to modeling and simulation. Some of the most recent modeling and simulation techniques, as well as some of the most accurate and sophisticated software in treating complex systems, are applied. All the original contributions in this book are jointed by the basic principle of a successful modeling and simulation process: as complex as necessary, and as simple as possible. The idea is to manipulate the simplifying assumptions in a way that reduces the complexity of the model (in order to make a real-time simulation), but without altering the precision of the results

JERS-1 SAR and LANDSAT-5 TM image data fusion: An application approach for lithological mapping

Satellite image data fusion is an image processing set of procedures utilise either for image optimisation for visual photointerpretation, or for automated thematic classification with low error rate and high accuracy. Lithological mapping using remote sensing image data relies on the spectral and textural information of the rock units of the area to be mapped. These pieces of information can be derived from Landsat optical TM and JERS-1 SAR images respectively. Prior to extracting such information (spectral and textural) and fusing them together, geometric image co-registration between TM and the SAR, atmospheric correction of the TM, and SAR despeckling are required. In this thesis, an appropriate atmospheric model is developed and implemented utilising the dark pixel subtraction method for atmospheric correction. For SAR despeckling, an efficient new method is also developed to test whether the SAR filter used remove the textural information or not. For image optimisation for visual photointerpretation, a new method of spectral coding of the six bands of the optical TM data is developed. The new spectral coding method is used to produce efficient colour composite with high separability between the spectral classes similar to that if the whole six optical TM bands are used together. This spectral coded colour composite is used as a spectral component, which is then fused with the textural component represented by the despeckled JERS-1 SAR using the fusion tools, including the colour transform and the PCT. The Grey Level Cooccurrence Matrix (GLCM) technique is used to build the textural data set using the speckle filtered JERS-1 SAR data making seven textural GLCM measures. For automated thematic mapping and by the use of both the six TM spectral data and the seven textural GLCM measures, a new method of classification has been developed using the Maximum Likelihood Classifier (MLC). The method is named the sequential maximum likelihood classification and works efficiently by comparison the classified textural pixels, the classified spectral pixels, and the classified textural-spectral pixels, and gives the means of utilising the textural and spectral information for automated lithological mapping

The efficient use of data from different sources for production and application of digital elevation models

The emphasis of the investigation reported in this thesis is on the use of digital elevation data of two resolutions originating from two different sources. The high resolution DEM was captured from aerial photographs (first source) at a scale of 1:30,000 and the low resolution DEM was captured from SPOT images (second source). It is well known that the resolution of DEM data depends a great deal on the scale of the images used. The technique for capturing DEMs is static measurement of the spot heights in a regular grid. The grid spacing of the high resolution DEM was 30 m, and of the low resolution DEM was 100 m. The aims of this thesis are as follows: 1. To assess the feasibility of using SPOT stereodata as a source of height information and merged with data from aerial photography. This is carried out by comparison of the elevation data derived from SPOT with the digital elevation data derived from aerial photography. From the comparison of these two sources of height information, some results are derived which show the possible heighting accuracy levels which can realistically be achieved. A systematic error in the estimated average of the elevation differences was found and many tests have been carried out to find the reasons for the presence of this systematic error. 2. To develop methods to manipulate the captured data. 2.1. Gross error (blunder) detection. Blunders made during the data capturing procedure affect the accuracy of the final product. Therefore it is necessary to trap and to remove them. A pointwise local self-checking blunder detection algorithm was developed in order to check the grid elevation data, particularly those which are derived from the second source. 2.2. Data coordinates transformation. The data must be transformed into a common projection in order to be directly comparable. The projection and coordinate systems employed are studied in this project, and the errors caused by the transformations are estimated. 2.3. Data merging. Data of different reliability have to be merged into a single set of data. In this project data from two different sources are merged in order to create a final product of known and uniform accuracy. The effect of the lower resolution source on the high resolution source was studied, in dense and in sparse form. 2.4. Data structure. To structure the data by changing the format in order to be in an acceptable form for DEM creation and display, through the commercially available Laser-Scan package DTMCREATE. 3. DEM production and contouring. To produce DEMs from the initial data and that derived from the two merged sources, and to find the accuracy of the interpolation procedure by comparing the derived interpolated data with the high resolution DEM which has been derived from aerial photography. Finally to interpolate contours directly from the "raw" SPOT data and to compare them with those derived from the aerial photography in order to find out the feasibility and capability of using SPOT data in contouring for topographic maps

Earth Resources: A continuing bibliography with indexes, issue 36

This bibliography lists 576 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between October 1 and December 31, 1982. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

THE APPLICATION OF REMOTE SENSING TECHNIQUES IN HYDROLOGY

REMOTE SENSING, which may be simplistically defined as ’the collection and interpretation of emitted or reflected radiation from a body’, offers the potential for accurate interpolation of surface data and even for its direct measurement on scales ranging from local to world wide. This dissertation has been written primarily for the hydrologist, engineer, environmentalist or student who needs to measure changes either in space or time of hydrological variables such as water quality, but who has little practical knowledge of remote sensing or how it may be of assistance to him. It may be regarded as a reference document which, as a result of internal cross referencing and comprehensive external subject referencing, should enable the reader to acquire a background knowledge of remote sensing theory which is relevant to his interests, to understand the advantages and difficulties of applying remote sensing techniques to his measurement problem and to obtain further information about remote sensing applications which have already been undertaken within his field of interest. The dissertation centres on the hydrological situation in England and Wales by initially outlining the structure of their water industries. The main hydrological measurement objectives in terms of water resources, water supply, effluent disposal and flood prediction and warning are identified and some advantages of incorporating remote sensing into hydrological measurement programmes are suggested. The physical theory of remote sensing is described and the main methods of collecting and analysing remotely sensed data are given. A topic by topic analysis of the most suitable ways of tackling specific hydrological measurement problems through the use of remote sensing is made and the dissertation concludes with an assessment of the likely future use of remote sensing in hydrological measurement programmes in genera

Digital processing of satellite images for geological applications with examples from North-East Scotland and North-West Malaysia

This study describes the use of Landsat MSS and TM for geological applications in two Scottish areas: Lochindorb and Loch Tuel; and one Malaysian area: Kedah-Perak. The areas are poorly exposed and highly vegetated. The data were digitally processed with the objective of producing more interpretable images. The processes include contrast enhancement, ratioing, subtraction, principal component analysis, discriminant analysis, filtering, the combination of images as colour composites, and producing negative images of the data. Geological interpretation of the most informative images was undertaken by visual interpretation. In the Lochindorb area, Landsat MSS imagery did not prove useful for superficial deposits mapping, and the resolution offers by the TM is still not sufficient for semi-detailed mapping at scale 1: 50,000. The combination of TM imagery and aerial photographs, however, made the mapping task easier and produced "better" map. In the Kedah-Perak area, textural information is more important than spectral information for lithological interpretation and many image units correlate well with major mapped rocks. Lineaments are well expressed on Landsat imagery and are mapped for the Loch Tummel and Kedäh-Perak areas. The lineament maps for both areas confirm many mapped faults and reveal a new prominent lineaments (probably faults). For the Loch Tummel area, the relative merits of TM versus MSS data were examined. Both produced similar results regarding major lineament orientations, but the TM provides a good improvement over the MSS in the ability to map lineaments. For both areas, lineaments appear to be correlated with geomorphology (lithology), and with the occurrence of ore deposits and probably geologic structure for the Kedah-Perak area. Landsat imagery can be used to aid lithological mapping in Malaysia, but has not proved useful for Scotland (U. K. ) because of different objectives and constraints. However, Landsat imagery is an effective tool in mapping lineaments for both areas

Advanced photon counting techniques for long-range depth imaging

The Time-Correlated Single-Photon Counting (TCSPC) technique has emerged as a candidate approach for Light Detection and Ranging (LiDAR) and active depth imaging applications. The work of this Thesis concentrates on the development and investigation of functional TCSPC-based long-range scanning time-of-flight (TOF) depth imaging systems. Although these systems have several different configurations and functions, all can facilitate depth profiling of remote targets at low light levels and with good surface-to-surface depth resolution. Firstly, a Superconducting Nanowire Single-Photon Detector (SNSPD) and an InGaAs/InP Single-Photon Avalanche Diode (SPAD) module were employed for developing kilometre-range TOF depth imaging systems at wavelengths of ~1550 nm. Secondly, a TOF depth imaging system at a wavelength of 817 nm that incorporated a Complementary Metal-Oxide-Semiconductor (CMOS) 32×32 Si-SPAD detector array was developed. This system was used with structured illumination to examine the potential for covert, eye-safe and high-speed depth imaging. In order to improve the light coupling efficiency onto the detectors, the arrayed CMOS Si-SPAD detector chips were integrated with microlens arrays using flip-chip bonding technology. This approach led to the improvement in the fill factor by up to a factor of 15. Thirdly, a multispectral TCSPC-based full-waveform LiDAR system was developed using a tunable broadband pulsed supercontinuum laser source which can provide simultaneous multispectral illumination, at wavelengths of 531, 570, 670 and ~780 nm. The investigated multispectral reflectance data on a tree was used to provide the determination of physiological parameters as a function of the tree depth profile relating to biomass and foliage photosynthetic efficiency. Fourthly, depth images were estimated using spatial correlation techniques in order to reduce the aggregate number of photon required for depth reconstruction with low error. A depth imaging system was characterised and re-configured to reduce the effects of scintillation due to atmospheric turbulence. In addition, depth images were analysed in terms of spatial and depth resolution

Compensating for topographic information from satellite imagery in mountain environments

The use of satellite image data for vegetation mapping and forestry inventory in mountain environments has been greatly restricted by the scene digital values containing a mixture of variations which are due partly to surface cover (albedo) and partly to topography (illumination). Landsat Thematic Mapper (TM) data were selected for a portion of the Rocky Mountains in the Kananaskis Valley, Alberta, Canada and used to derive secondary data channels that sought to compensate for topographic information, by isolating the response due to surface cover. Two multispectral techniques were used: band ratioing and principal component analysis. In both cases, the generated channels represented the difference between the three spectral groups of bands for TM data: visible, near and middle (shortwave) infra-red. Multi-channel ratio and component combinations were used in an unsupervised clustering procedure that defined homogeneous ground areas. When the original pixel values were replaced by the average brightness for their respective clusters, the resulting image channels represented each of the multispectral bands as if the surface were flat. Selective principal components proved more successful than band ratioing, being less susceptible to noise and allowing input from more than two bands each. These component channels created a final classification which had a higher overall accuracy than those for studies in adjacent mountain environments using supervised classification and was comparable to those which also incorporated topographic data. The study was successful in identifying a different approach to topographic correction without having to acquire digital elevation models and considerable ground knowledge. This technique has much potential for expediting forest cover inventory and vegetation mapping in mountain environments and represents a new and promising application for principal component analysis

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