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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

The analysis of spatial-temporal dynamics of urban landscape structure : a comparison of two petroleum-oriented cities /

Tang, Junmei, January 1900 (has links)
Thesis (Ph. D.)--Texas State University-San Marcos, 2007. / Vita. Includes bibliographical references (leaves 120-136).
52

Geospatial technology applications to strawberry, grape and citrus production systems

Saraswat, Dharmendra. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 226-244).
53

Processing of onboard images to assist automatic forward motion compensation for micro-satellites

Mouton, Christiaan J. 03 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: South Africa's first micro satellite, SUNSAT, was operational in orbit for 23 months since its NASA-sponsored launch on February 23, 1999. SUNSAT is a graduate studentdeveloped satellite from the University of Stellenbosch in South Africa. Research work is in progress on improving SUNSAT's 15m multi-spectral imager to a 2.5m-resolution multi-sensor imager. This will require the use of Forward Motion Compensation for exposure control. This thesis presents Automatic Forward Motion Compensation for Micro Satellites using a new earth sensor that measures the bore-sight projection's speed on the earth directly. This sensor will have no drift and will make use of a series of images and crosscorrelation of them. The high-resolution imager's bore-sight motion can be controlled by this technique to ensure high quality stereo images. A control system based on the DLR-TUBSAT was designed and is simulated in MATLAB. This technique of measuring the bore-sight projection's speed on the earth directly was tested on a 2-axis telescope and used to measure random movement of a satellite. / AFRIKAANSE OPSOMMING: SUNSAT, Suid Afrika se eerste satelliet was vir 23 maande in werking in 'n wentelbaan na sy NASA-geborgde lasering op 23 Februarie 1999. SUNSAT is 'n satelliet wat ontwikkel is deur nagraadse studente aan die Universiteit van Stellenbosch. Navorsingswerk is aan die gang om SUNSAT se 15m resolusie multi-spektrale kamera te verbeter tot 'n 2.5m resolusie multi-sensor kamera. Die navorsing sal die gebruik van Voorwaartse Bewegingskompensasie benodig. Die tesis handeloor automatiese voorwaartse bewegingskompensasie vir mikrosatelliete deur gebruik te maak van 'n nuwe aardgerigte sensor, wat die siglyn projeksie se snelheid op die aarde direk sal meet. Die sensor sal gebruik maak van 'n reeks foto's wat gekruiskorreleer word en sal geen tempo-wegdrywing hê nie. Hoë resolusie kameras se siglyn kan deur middel van hierdie tegniek beheer word om hoë kwaliteit stereo foto's te verseker. 'n Beheerstelsel wat gebaseer is op dié van DLR-TUBSAT, is ontwerp en is gesimuleer in MATLAB. Die tegniek om die siglyn projeksie se snelheid op die aarde direk te meet, is getoets op 'n 2-as teleskoop en is gebruik om onverwille keurige beweging van 'n satelliet te meet.
54

Concise analysis and testing of a software model of a satellite remote sensing system used for image generation

Van der Westhuizen, Lynette 12 1900 (has links)
Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: The capability of simulating the output image of earth observation satellite sensors is of great value, as it reduces the dependency on extensive field tests when developing, testing and calibrating satellite sensors. The aim of this study was to develop a software model to simulate the data acquisition process used by passive remote sensing satellites for the purpose of image generation. To design the software model, a comprehensive study was done of a physical real world satellite remote sensing system in order to identify and analyse the different elements of the data acquisition process. The different elements were identified as being the target, the atmosphere, the sensor and satellite, and radiation. These elements and a signature rendering equation are used to model the target-atmosphere-sensor relationship of the data acquisition process. The signature rendering equation is a mathematical model of the different solar and self-emitted thermal radiance paths that contribute to the radiance reaching the sensor. It is proposed that the software model be implemented as an additional space remote sensing application in the Optronics Sensor Simulator (OSSIM) simulation environment. The OSSIM environment provides the infrastructure and key capabilities upon which this specialist work builds. OSSIM includes a staring array sensor model, which was adapted and expanded in this study to operate as a generic satellite sensor. The OSSIM signature rendering equation was found to include all the necessary terms required to model the at-sensor radiance for a satellite sensor with the exception of an adjacency effect term. The equation was expanded in this study to include a term to describe the in-field-of-view adjacency effect due to aerosol scattering. This effect was modelled as a constant value over the sensor field of view. Models were designed to simulate across-track scanning mirrors, the satellite orbit trajectory and basic image processing for geometric discontinuities. Testing of the software model showed that all functions operated correctly within the set operating conditions and that the in-field-of-view adjacency effect can be modelled effectively by a constant value over the sensor field of view. It was concluded that the satellite remote sensing software model designed in this study accurately simulates the key features of the real world system and provides a concise and sound framework on which future functionality can be expanded. / AFRIKAANSE OPSOMMING: Dit is nuttig om ’n sagteware program te besit wat die gegenereerde beelde van ’n satellietsensor vir aarde-waarneming kan naboots. So ’n sagteware program sal die afhanklikheid van breedvoerige veldwerktoetse verminder gedurende die ontwerp, toetsing en kalibrasie fases van die ontwikkeling van ’n satellietsensor. Die doel van hierdie studie was om ’n sagteware model te ontwerp wat die dataverwerwingsproses van ’n passiewe satelliet afstandswaarnemingstelsel kan naboots, met die doel om beelde te genereer. Om die sagteware model te ontwerp het ’n omvattende studie van ’n fisiese regte wêreld satelliet afstandswaarnemingstelsel geverg, om die verskillende elemente van die dataverwerwingsproses te identifiseer en te analiseer. Die verskillende elemente is geïdentifiseer as die teiken, die atmosfeer, die sensor en satelliet, en vloed. Hierdie elemente, tesame met ’n duimdrukvergelyking, is gebruik om die teiken-atmosfeer-sensor verhouding van die dataverwerwingsproses te modelleer. Die duimdrukvergelyking is ’n wiskundige model van die verskillende voortplantingspaaie van gereflekteerde sonvloed en self-stralende termiese vloed wat bydra tot die totale vloed wat die sensor bereik. Dit is voorgestel dat die sagteware model as ’n addisionele ruimte afstandswaarnemingtoepassing in die ‘Optronics sensor Simulator’ (OSSIM) simulasie-omgewing geïmplementeer word. Die OSSIM simulasie-omgewing voorsien die nodige infrastruktuur en belangrike funksies waarop hierdie spesialis werk gebou kan word. OSSIM het ’n starende-skikking sensor model wat in hierdie studie aangepas is en uitgebrei is om as ’n generiese satellietsensor te funksioneer. Die OSSIM duimdrukvergelyking bevat al die nodige radiometriese terme, behalwe ’n nabyheids-verstrooiing term, om die vloed by die satellietsensor te modeleer. Die duimdrukvergelyking is uitgebrei in hierdie studie om ’n term in te sluit wat die verstrooiing van vloed vanaf naby-geleë voorwerpe, as gevolg van aerosol verstrooiing, kan beskryf. Die nabyheids-verstrooiing is gemodeleer as ’n konstante waarde oor die sigveld van die sensor. Modelle is ontwerp om die beweging van oor-baan skandering-spieëls en die satelliet wentelbaan trajek te bereken. ’n Basiese beeldverwerkings model is ook ontwerp om diskontinuïteite in geometriese vorms in die sensor beelde reg te stel. Toetsing van die sagteware model het gewys dat al die funksies korrek gefunksioneer het binne die limiete van die vasgestelde operasionele voorwaardes. Die toets resultate het ook bewys dat die in-sig-veld nabyheids-verstrooiing akkuraat gemodeleer kan word as ’n konstante waarde oor die sensor sigveld. Daar is tot die gevolgtrekking gekom dat die satelliet afstandswaarneming sagteware model wat in hierdie studie ontwerp is al die belangrikste kenmerke van die werklike wêreld stelsel kan simuleer. Die model vorm ’n beknopte en stewige raamwerk waarop toekomstige werk uitgebrei kan word.
55

Topografia convencional na aferição de áreas obtidas por georreferenciamento e Google Earth / Conventional survey to check topographical areas obtained by google earth image and georeferencing procedure

Felipe, Alexandre Luis da Silva [UNESP] 07 August 2015 (has links) (PDF)
Made available in DSpace on 2015-12-10T14:23:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-07. Added 1 bitstream(s) on 2015-12-10T14:30:04Z : No. of bitstreams: 1 000853186.pdf: 790204 bytes, checksum: 5290f2778fd056916d241a6d1218d3db (MD5) / O presente trabalho objetivou comparar distâncias horizontais e áreas de um polígono considerando pontos homólogos obtidos através de levantamento topográfico convencional realizado por Estação Total Nikon Nivo 322d, levantamento georreferenciado por receptor GNSS AshTech Pro Mark 200 e imagem do Google Earth. O processamento do levantamento topográfico foi realizado através programa computacional DataGeosis versão Office que acusou elevada precisão, constituindo-se em referência. Os dados obtidos através do receptor GNSS foram pós-processados pelo software GNSS Solution e os obtidos pelo Google Earth foram submetidos ao software AutoCAD 13 para desenho. Os dados assim obtidos permitiram a geração de plantas e de cálculo de distâncias horizontais e áreas nos três casos. Foi possível se plotar as três plantas em único desenho por se considerar para o primeiro ponto da poligonal obtida por levantamento topográfico convencional, o mesmo par de coordenadas que o obtido pelo receptor GNSS. Concluiu-se que valor de área obtida através do Google Earth ficando próximo do valor da referência, bem como seu entorno, não significa a precisão do polígono visto que comprometedoras diferenças em distâncias ora à maior ora à menor podem estar sendo compensadas, no entanto pode-se admitir esse procedimento para uso em planejamento rural generalizado. / The purpose of this study was to compare horizontal distances and areas of a polygon considering homologous points obtained through conventional survey using a Nikon Nivo total station 322d, a GNSS receiver AshTech Pro Mark 200 for georeferenced survey and Google Earth image. The processing of the survey made by computer program Datageosis Office version accused high precision constituting as the reference. The data obtained from the GNSS receiver were post-processed by the GNSS software Solution and the data obtained by Google Earth was submitted to the 13 AutoCAD software for drawing. The data obtained enabled the maps generation and calculation horizontal distances and areas in all three cases. It was possible to plot the three maps in a unique design by considering for the first point of the polygon obtained by conventional surveying, the same pair of coordinates obtained by the GPS receiver. It was concluded that the area value obtained through Google Earth being next to the reference value, does not means the polygon precision due to the fact of differences in distances sometimes the largest and sometimes the smallest being compensated, however it is possible to admit this procedure for use in general rural planning
56

Comparison of pixel-based and object-oriented classification approaches for detection of camouflaged objects

Lubbe, Minette 28 February 2012 (has links)
M.A. / The dissertation topic is the comparison of pixel-based and object-oriented image analysis approaches for camouflaged object detection research. A camouflage field trial experiment was conducted during 2004. For the experiment, 11 military vehicles were deployed along a tree line and in an open field. A subset of the vehicles was deployed with a variety of experimental camouflage nets and a final subset was left uncovered. The reason for deploying the camouflaged objects in the open without the use of camouflage principals was to create a baseline for future measurements. During the next experimental deployment, the camouflaged targets will be deployed according to camouflage principals. It must be emphasised that this is an experimental deployment and not an operational deployment. Unobstructed entity panels were also deployed and served as calibration entities. During the trial, both airborne (colour aerial photography) and space borne (multi-spectral QuickBird) imagery were acquired over the trial sites, and extensive calibration and ground truthing activities were conducted in support of these acquisitions. This study further describes the processing that was done after acquisition of the datasets. The goal is to determine which classification techniques are the most effective in the detection of camouflaged objects. This will also show how well or poor the SANDF camouflage nets and paint potentially perform against air and space based sensors on the one hand and classification techniques on the other. Using this information, DPSS can identify the nets and paints that need to be investigated for future enhancements (e.g. colour selection, colour combinations, base material, camouflage patterns, entity shapes, entity textures, etc.). The classification techniques to be used against SANDF camouflaged objects will also give an indication of their performance against camouflaged advesarial forces in the future.
57

Onboard image geo-referencing for LEO satellites

Van den Dool, Riaan 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005. / The next generation of small satellites will require significant onboard data processing and information extraction capabilities to keep up with industry demands. The need for value added information products is growing as accessibility and user education is improving. Image geo-referencing is one of the image processing steps needed to transform raw images into usable information. Automating this process would result in a vast improvement in processing time and cost. As part of the background study, the imaging process is described and a model of the process is created. The sources of distortion that are present in the imaging process are described and techniques to compensate for them are discussed. One method that stands out is using wavelet analysis for the precision geo- referencing of images. Wavelets are used in this thesis for automatic ground control point identification. Finally, the automatic ground control point algorithm is used for band-alignment of a set of aerial images at sub pixel accuracy as a demonstration of the quality of ground control points that can be found.
58

Statistical correlation between economic activity and DMSP-OLS night light images in Florida

Unknown Date (has links)
The Defense Meteorological Satellite Program (DMSP) Optical Line Scan (OLS) instruments collect data from an altitude of approximately 830km above the surface of the Earth. The night light data from these instruments has been shown to correlate by lit area with national level Gross Domestic Product (GDP) and to correlate with GDP at the State level by total radiance value. Very strong correlation is found between the night light data at a new, larger scale, the Metropolitan Statistical Area (MSA) within the state of Florida. Additional statistical analysis was performed to determine which industries within each MSA explain the greatest amount of variance in the night light data. Industrial variables exhibited strong multi-collinearity. It is therefore impossible to determine which industries explain the greatest variance in the night light image data. / by Dolores Jane Forbes. / Thesis (M.A.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.
59

Characterization of properties and spatiotemporal fields of mineral aerosol and its radiative impact using CALIPSO data in conjunction with A-Train satellite and ground-based observations and modeling

Choi, Hyung Jin 13 June 2011 (has links)
The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission provides unique measurements of vertical profiles of aerosols and clouds and their properties during day and night-time over all types of surfaces. This information has the potential to significantly improve our understanding of the properties and effects of aerosol and clouds. This dissertation presents the results of a comprehensive analysis of CALIPSO lidar (version 2 and version 3.01) data in conjunction with A-Train satellite and ground-based observations aimed at characterizing mineral aerosol in East Asia and other major dust sources. The specific objectives were to characterize the spatial distribution and properties of atmospheric dust in the dust source regions using new CALIOP (version 3.01) data in conjunction with satellite MODIS, OMI, and CloudSat data and ground-based meteorological and lidar data; investigate changes in the vertical distribution and properties of dust during mid- and long-range transport; perform a modeling of the optical properties of nonspherical dust particles, and assess the radiative forcing and heating/cooling rates of atmospheric dust by performing radiative transfer modeling constrained by satellite data in major dust source regions.
60

Exploration and application of MISR high resolution Rahman Pinty-Verstraete time series

Liu, Zhao January 2017 (has links)
Thesis (Doctor of Engineering in Electrical Engineering)--Cape Peninsula University of Technology, 2017. / Remote sensing provides a way of frequently observing broad land surfaces. The availability of various earth observation data and their potential exploitation in a wide range of socioeconomic applications stimulated the rapid development of remote sensing technology. Much of the research and most of the publications dealing with remote sensing in the solar spectral domain focus on analysing and interpreting the spectral, spatial and temporal signatures of the observed areas. However, the angular signatures of the reflectance field, known as surface anisotropy, also merit attention. The current research took an exploratory approach to the land surface anisotropy described by the RPV model parameters derived from the MISR-HR processing system (denoted as MISR-HR anisotropy data or MISR-HR RPV data), over a period of 14+ years, for three typical terrestrial surfaces in the Western Cape Province of South Africa: a semi-desert area, a wheat field and a vineyard area. The objectives of this study were to explore (1) to what extent spectral and directional signatures of the MISR-HR RPV data may vary in time and space over the different targets (landscapes), and (2) whether the observed variations in anisotropy might be useful in classifying different land surfaces or as a supplementary method to the traditional land cover classification method. The objectives were achieved by exploring the statistics of the MISR-HR RPV data in each spectral band over the different land surfaces, as well as seasonality and trend in these data. The MISR-HR RPV products were affected by outliers and missing values, both of which influenced the statistics, seasonality and trend of the examined time series. This research proposes a new outlier detection method, based on the cost function derived from the RPV model inversion process. Removed outliers and missing values leave gaps in a MISR-HR RPV time series; to avoid introducing extra biases in the statistics of the anisotropy data, this research kept the gaps and relied on gap-resilient trend and seasonality detection methods, such as the Mann-Kendal trend detection and Lomb-Scargle periodogram methods. The exploration of the statistics of the anisotropy data showed that RPV parameter rho exhibited distinctive over the different study sites; NIR band parameter k exhibits prominent high values for the vineyard area; red band parameter Theta data are not that distinctive over different study sites; variance is important in describing all three RPV parameters. The explorations on trends also demonstrated interesting findings: the downward trend in green band parameter rho data for the semi-desert and vineyard areas; and the upward trend in blue band parameters k and Theta data for all the three study sites. The investigation on seasonality showed that all the RPV parameters had seasonal variations which differed over spectral bands and land covers; the results confirmed expectations in previous literature that parameter varies regularly along the observation time, and also revealed seasonal variations in the parameter rho and Theta data. The explorations on the statistics and seasonality of the MISR-HR anisotropy data show that these data are potentially useful for classifying different landscapes. Finally, the classification results demonstrated that both red band parameter rho data and NIR band parameter k data could successfully separate the three different land surfaces in this research, which fulfilled the second primary objective of this study. This research also demonstrated a classification method using multiple RPV parameters as the classification signatures to discriminate different terrestrial surfaces; significant separation results were obtained by this method.

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