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Spatial Accuracy in Orthophoto produced using UAV Photographic Images / Lägesnoggrannhet i ortofoton framställda med UAV-fotonStensson, Lily January 2016 (has links)
The popularity of using UAV in image-taking for the production of 3D models and orthophotos has increased over time. Karlskoga Municipality has recently acquired an UAV to produce their own 3D models and orthophotos. This project paper aims to study the geospatial accuracy of the orthophotos and DEM files produced using the images taken with their UAV. The flight takes only a few minutes but a considerable time is spent in the production processes. Difficulty is experienced in determining the right center point for most GCPs. Produced orthophotos in the software Photoscan have a resolution from 1.7 to 2.4 centimeters while DEM files have a resolution from 3.4 to 4.8 centimeters. Four orthophotos and four DEM files are produced where GCPs are used and not used and at two different flight heights, 76 and 105 meters. The spatial data of the ten GCPs are identified on the orthophotos and DEM files in ArcMap and compared with GNSS NRTK measurements and Lantmäteriet's data. A visual control in terms of completeness of data, alignment, residual tilt and scale is also done. Standard deviations in plane for orthophotos there GCPs are not used are greater than 2 meters, while there GCPs are used are around 0.7 meters. Standard deviations for DEM files are observed at 0.8 meters.
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Estimation of individual tree metrics using structure-from-motion photogrammetry.Miller, Jordan Mitchell January 2015 (has links)
The deficiencies of traditional dendrometry mean improvements in methods of tree mensuration are necessary in order to obtain accurate tree metrics for applications such as resource appraisal, and biophysical and ecological modelling. This thesis tests the potential of SfM-MVS (Structure-fromMotion with Multi-View Stereo-photogrammetry) using the software package PhotoScan Professional, for accurately determining linear (2D) and volumetric (3D) tree metrics. SfM is a remote sensing technique, in which the 3D position of objects is calculated from a series of photographs, resulting in a 3D point cloud model. Unlike other photogrammetric techniques, SfM requires no control points or camera calibration. The MVS component of model reconstruction generates a mesh surface based on the structure of the SfM point cloud.
The study was divided into two research components, for which two different groups of study trees were used: 1) 30 small, potted ‘nursery’ trees (mean height 2.98 m), for which exact measurements could be made and field settings could be modified, and; 2) 35 mature ‘landscape’ trees (mean height 8.6 m) located in parks and reserves in urban areas around the South Island, New Zealand, for which field settings could not be modified.
The first component of research tested the ability of SfM-MVS to reconstruct spatially-accurate 3D models from which 2D (height, crown spread, crown depth, stem diameter) and 3D (volume) tree metrics could be estimated. Each of the 30 nursery trees was photographed and measured with traditional dendrometry to obtain ground truth values with which to evaluate against SfM-MVS estimates. The trees were destructively sampled by way of xylometry, in order to obtain true volume values. The RMSE for SfM-MVS estimates of linear tree metrics ranged between 2.6% and 20.7%, and between 12.3% and 47.5% for volumetric tree metrics. Tree stems were reconstructed very well though slender stems and branches were reconstructed poorly.
The second component of research tested the ability of SfM-MVS to reconstruct spatially-accurate 3D models from which height and DBH could be estimated. Each of the 35 landscape trees, which varied in height and species, were photographed, and ground truth values were obtained to evaluate against SfM-MVS estimates. As well as this, each photoset was thinned to find the minimum number of images required to achieve total image alignment in PhotoScan and produce an SfM point cloud (minimum photoset), from which 2D metrics could be estimated. The height and DBH were estimated by SfM-MVS from the complete photosets with RMSE of 6.2% and 5.6% respectively. The height and DBH were estimated from the minimum photosets with RMSE of 9.3% and 7.4% respectively. The minimum number of images required to achieve total alignment was between 20 and 50. There does not appear to be a correlation between the minimum number of images required for alignment and the error in the estimates of height or DBH (R2 =0.001 and 0.09 respectively). Tree height does not appear to affect the minimum number of images required for image alignment (R 2 =0.08).
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Kvalitetskontroll av en 3D-modells ärdvda georeferering : Med hjälp av crowdsourcing för insamling av dataKarlsson, Peter, Friberg, Kalle January 2017 (has links)
Städer och infrastruktur är i ständig utveckling och arbetet att uppdatera befintlig och äldre data blir ett mödosamt och dyrt arbete. Lantmäteriet undersöker möjligheter att effektivisera samhällsprocessen med hjälp av 3D-data. Det är framförallt en lösning på en mer effektiv detaljplanering och byggprocess som önskas. Vi föreslår en metod där en äldre georeferering hos en 3D-modell utnyttjas för att uppdatera modellen med nytt objekt. Detta betyder att georefereringen ärvs från det äldre objektet. Syftet med studien är att utföra tester och avgöra om lägesosäkerhet som Lantmäteriet ställer som krav vid utförande av detaljmätning ka nuppnås. Kommer det nya objektet att ärva den äldre georefereringen, och vilken avvikelse går det att uppnå i relation mellan nytt objekt och äldre modell? Det nya objektet fotograferas med olika kameror för att simulera en imaginär men realistisk situation, där bilder har samlats in genom crowdsourcing och microtasks. En modell skapades över hus 45 Högskolan Gävle med hjälp av äldre bilder som fotograferats med en UAS. Fotograferingen skedde på 70 m flyghöjd, där även snedbilder har tagits med en lägre flyghöjd runt byggnaden. I programmet Agisoft PhotoScan användes bilderna för att skapa 3D-punktmoln och 3D-bildmodeller. Studien visar att nya objekt kan ärva georeferering från en äldre modell. Ett snitt från båda hörnen visar ett resultat över testmätningar visar en sammanlagd avvikelse i plan på 0,051 m och 0,041 m i höjd. Lantmäteriet ställer krav för detaljmätning med fyra standardnivåer. Där standardnivå 2 har som krav att en lägesosäkerhet på som mest 0,1 m ska kunna garanteras, en nivå som används för kommunaldetaljplanering och vid detaljplanering av tätort. Två olika tekniker används för att utföra mätningar, direkt i 3D-bildsmodell och direkt i 3D-punktmoln, mätningarna utförs även i 2D och i 3D. Det stora problemet med metoden är arbetstiden är väldigt stor, och att Agisoft PhotoScan har begränsningar och direkta problem när det ska användas för att utföra mätningar i en 3D-bildmodell.
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Utvärdering av lägesosäkerheter i ortofoton framtagna med hjälp av DJI Phantom 4 RTK / Evaluation of position uncertainties in orthophotos developed with a DJI Phantom 4 RTKLarsson, Johan, Stark, Marcus January 2019 (has links)
Flygfotografering med Unmanned Aircraft System (UAS) är i jämförelse med traditionell fotogrammetri effektivare, billigare och säkrare vilket har medfört att denna teknik föredras av många aktörer. Ett tidskrävande arbete som varit svårt att kringgå är att etablera flygsignaler på marken som används för att georeferera och kontrollera flygbilderna med. Under 2018 presenterade UAS-tillverkaren DJI sin nya quadcopter med integrerad Real-Time Kinematic (RTK)-modul. I samband med detta kan kontinuerliga och noggranna positioner levereras via Nätverks-RTK (NRTK) och behovet av markstödpunkter reduceras. I denna studie undersöktes lägesosäkerheterna i plan för ortofoton som framställdes med hjälp av en DJI Phantom 4 RTK där flygbilderna georefererades med begränsat antal eller utan markstödpunkter. Lägesosäkerheterna beräknades och kontrollerades enligt Handbok i mät- och kartfrågor (HMK) – Ortofoto, vilket är ett stöddokument inom ämnet. Vid framställning av ett ortofoto krävs även en digital terrängmodell (DTM) eller en digital ytmodell (Digital Surface Model, DSM) och kvaliteten av denna har stor inverkan på ortofotots kvalitet. I denna studie kontrollerades och utvärderades därför en del av den DSM som användes vid ortofotoframställning för respektive uppsättning enligt den tekniska specifikationen SIS-TS 21144:2016. Resultatet från studien visar att ett ortofoto går att framställas utan markstödpunkter och samtidigt klara kraven på specificerad lägesosäkerhet enligt HMK-standardnivå 3. Den sammanlagda lägesosäkerheten beräknades till 0,029 m vilket är 5 mm högre i jämförelse med ett ortofoto som baserats på traditionell georefereringsmetod, dvs. med markstödpunkter. Kravet på kvalitet i höjddata uppfylldes också för ortofotoframställning trots att en systematisk effekt i höjd uppkom. Denna effekt påverkade inte ortofotots koordinater i plan då standardosäkerheterna i höjd var låga. Resultatet visade att om två markstödpunkter adderades i vardera änden av området, kunde de systematiska effekterna i höjd minimeras och det var då möjligt att skapa en DSM som uppfyller kraven för detaljprojektering (noggrannhetsklass 1–3) enligt SIS-TS 21144:2016. / Aerial photography with UAS is in comparison with traditional photogrammetry more efficient, cheaper and safer which has led to this technology being preferred by many performers. A time-consuming job that has been difficult to avoid is to establish signals at the ground that are used for georeferencing and evaluate the results. In 2018, the UAS manufacturer DJI presented its new quadcopter with integrated Real-Time Kinematic (RTK) module. This allows continuous and accurate positions delivered via Network RTK (NRTK) and the need of ground control points can be reduced. In this study, investigations of the position uncertainties in orthophotos produced using a DJI Phantom 4 RTK carried out where the aerial images were georeferenced with limited numbers or without ground control points. The position uncertainties were calculated and controlled according to the Swedish HMK – Ortofoto (Orthophoto) which is a document within the subject. When producing an orthophoto, a digital terrain model (DTM) or a digital surface model (DSM) is also required and the quality of this has a great impact on the result. Therefore, a part of the DSM used for orthophoto production for each set was checked and evaluated according to the Swedish technical specification, SIS-TS 21144:2016. The result of the study shows that an orthophoto can be produced without ground control points and at the same time meet the requirements for specified position uncertainty according to HMK standard level 3. The total position uncertainty was calculated to be 0,029 m, which is 5 mm higher compared to the orthophoto based on the traditional georeferencing method, i.e. with ground control points. The requirement for quality in height data was also met for orthophoto production even though a systematic effect in height occurred. This effect did not affect the plane coordinates in the orthophoto because of the low standard uncertainties in height. The result showed that if two ground control points were added at each end of the area, the systematic effects were minimized, and it was possible to produce a DSM that fulfils the requirements for accuracy class 1-3 according to SIS-TS 21144:2016.
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Utvärdering av programvara/molntjänst för framställning av ortofoton med UAS-dataThorell, Fredrik, Nilsson, William January 2013 (has links)
Unmanned Aerial Vehicle (UAV) är en benämning på en obemannad flygande farkost. UAV är en benämning för själva farkosten och därför har Unmanned Aircraft System (UAS) tagit över eftersom det är ett begrepp som rör hela systemet som förutom flygfarkost innefattar start, landning, markstation och kommunikationslänk. Inom mätningsteknik är UAS ett relativt nytt begrepp och tekniken har sin historia mestadels inom det militära området. Syftet med denna studie är att analysera samt utvärdera två programvaror och en molntjänst för bearbetning och framtagning av ortofoto från UAS-data. De frågor som ställts inför arbetet är: kan en molntjänst ersätta ett avancerat datorprogram vid generering av ortofoton? Kan dessa datorprogram ge ett bra resultat utan hjälp av andra GIS-program? Vilket program är enklast att förstå och använda samt vilka är skillnaderna mellan programmen? Dessa frågor har besvarats genom användning av insamlat data och för att få utvärderingen rättvis har därför tre olika dataset skapats. Programtjänsterna som har utvärderats är Agisoft PhotoScan 0.9.0 och Pix4UAV Desktop/Cloud 2.1.2. Insamling av data har skett genom en flygning med en oktokopter över Fågelmyratippen i Dalarna. Resultaten visar att priset snabbt blir högt om endast Pix4UAV Cloud används och att överlag är PhotoScan billigare än Pix4UAV Desktop. Kvalitetsrapporten som följer med varje projekt är överskådlig i PhotoScan och mer ingående i Pix4UAV Desktop/Cloud. Trots samma indata blir utdatat olika vid bearbetning av de olika programmen, till exempel skiljer sig markupplösningen åt mellan programmen. Generellt är PhotoScan tydligare på att visa hur arbetsprocessen går till. Supporten hos båda företagen är bra, tips och tricks finns på respektive hemsida. Till PhotoScan finns även en manual för nedladdning samt en YouTube-kanal med instruktionsvideor. De enda slutsatserna vi drar är att Pix4UAV Cloud inte klarar av att ersätta ett avancerat bildbehandlingsprogram och att för tillfället bör ytterligare ett GIS-program användas som komplement för att få bästa resultat. I övrigt har vi endast skrapat på ytan av programmen och rekommenderar att läsaren tar till sig det vi skrivit under resultat och diskussion för att sedan bilda sig en egen uppfattning med hjälp av respektive programs prövotid. Till sist presenteras förslag på vidare studier inom ämnet. / Unmanned Aerial Vehicle (UAV) is a term for a remote controlled airbornevehicle. Since UAV is an acronym for the vehicle itself, Unmanned Aircraft Systems(UAS) has therefore replaced UAV, as it is a concept related to the wholesystem, beside the vehicle it also includes landing, ground station andcommunications link. Within land surveying UAS is a relatively new concept asthe technology has its history mainly associated to the military. The purposeof this study is to analyze and evaluate two software and a cloud service for processingand preparation of orthophotos from data collected with a UAS. The questions tobe answered in this thesis are: Can a cloud service replace an advancedcomputer software for generating orthophotos? Can these produce good resultswithout the help of other GIS software? Which software is the easiest tounderstand and to use and what are the main differences. These questions wereanswered by using collected data, and to get the evaluation fair three datasetshave been created. The software being evaluated are Agisoft PhotoScan andPix4UAV desktop/cloud. The data collection was done by a flight with an octokopterover Fågelmyratippen in Dalarna. The results show that the price quicklybecomes high if only Pix4UAV Cloud is used and that generally PhotoScan ischeaper than Pix4UAV Desktop. The quality report that comes with each projectis easy to understand in PhotoScan but more detailed in Pix4UAV Desktop/Cloud. Despitethe use of same data the results vary when processed, for example the groundresolution. Generally PhotoScan is better at showing the work process. Eachcompany’s support is good and they both have tips and tricks at their websites.On the Agisoft webpage there is a manual available for download and they alsohave a YouTube-channel with instruction videos. The conclusion is that thecloud service is not capable of replacing an advance image processing software.Another conclusion is that for the moment another GIS-program should be used toget the best results. We like to point out that we only scratched the surfaceof the software and we recommend that the reader embrace what we write inresults and discussion to then form their own opinion by using the softwareevaluation period. I the last part we present subjects of further study.
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Characterization of Landslide Geometry and Movement Near Black Canyon City, ArizonaJanuary 2016 (has links)
abstract: I investigate the Black Canyon City landslide (BCC landslide), a prominent deep-seated landslide located northeast of Black Canyon City, Arizona. Although the landslide does not appear to pose a significant hazard to structures, its prominent features and high topographic relief make it an excellent site to study the geologic setting under which such features develop. This study has the potential to contribute toward understanding the landscape evolution in similar geologic and topographic settings, and for characterizing the underlying structural processes of this deep-seated feature. We use field and remotely-based surface geology and geomorphological mapping to characterize the landslide geometry and its surface displacement. We use the Structure from Motion (SfM) method to generate a 0.2 m resolution digital elevation model and rectified ortho-photo imagery from unmanned aerial vehicle (UAV) - and balloon-based images and used them as the base map for our mapping. The ~0.6 km2 landslide is easily identified through remotely-sensed imagery and in the field because of the prominent east-west trending fractures defining its upper extensional portion. The landslide displaces a series of Early and Middle Miocene volcanic and sedimentary rocks. The main head scarp is ~600 m long and oriented E-W with some NW-SE oriented minor scarps. Numerous fractures varying from millimeters to meters in opening were identified throughout the landslide body (mostly with longitudinal orientation). The occurrence of a distinctive layer of dark reddish basalt presents a key displaced marker to estimate the long-term deformation of the slide mass. Using this marker, the total vertical displacement is estimated to be ~70 m, with maximum movement of ~95 m to the SE. This study indicates that the landslide motion is translational with a slight rotational character. We estimate the rate of the slide motion by resurvey of monuments on and off the slide, and examination of disturbed vegetation located along the fractures. The analysis indicates a slow integrated average landslide velocity of 10-60 mm/yr. The slide motion is probably driven during annual wet periods when increased saturation of the slide mass weakens the basal slip surface and the overall mass of the slide is increased. Results from our study suggest that the slide is stable and does not pose significant hazard for the surrounding area given no extreme changes in the environmental condition. Although the landslide is categorized as very slow (according to Cruden and Varnes, 1996), monitoring the landslide is still necessary. / Dissertation/Thesis / Masters Thesis Geological Sciences 2016
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Uso de veículos aéreos não tripulados para mapeamento e avaliação de erosão urbana / Use of unmanned arial vehicles (UAV) for mapping and evaluating urban erosion (in Goiás state, Brazil)Rodrigues , Avilmar Antonio 25 November 2016 (has links)
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Previous issue date: 2016-11-25 / This research aimed to evaluate the use of Unmanned Aerial Vehicle (UAV) as a platform for taking aerial photographs for mapping erosion planialtimetric located in urban areas. In addition, we evaluated the need to use or not to field control points for the generation of Digital Surface Model (DSM) and ortomosaico as tools to evaluate the erosive process. Despite the wide variation in attitude of aerial photographs that make up the aerophotogrammetric block arising from the instability of the UAV, it was possible to generate the MDS and ortomosaico with or without control points. This research was conducted in two urban erosions located in Goiania in Sector Fonte Nova in the stream of grass and the other in Silvânia called foot-washing. Whole generation of MDS, Digital Surface Model (MDT) and ortomosaico were performed in Agisoft PhotoScan program in semi-automatic processing, if used control points, or automatic without control points. The ortomosaicos generated without control points presented rotation, translation and scale of different generated with support. In addition, MDS generated without control points showed elevation or lowering of the reference surface with respect to the generated control, it is emphasized that these discrepancies are not constant. When performing automatic conversion of MDS to MDT, it was realized that the program was not able to eliminate the shrub vegetation located within the erosion. The vegetation or tree, shrub or undergrowth (grass) prevents proper limitation of erosion to the volume calculation. But unlike the MDS generated between two distinct epochs identifies the changes in the interval of time in areas without vegetation. The use of control points was essential to ensure the orientation, scale and the reference plane in the products generated from aerial photographs and thus evaluate the changes. Anyway, the UAV can be used as a platform for taking aerial photographs for generating cartographic products that enable the mapping and evaluation of erosions. / Esta pesquisa teve por objetivo avaliar a utilização do Veículo Aéreo Não Tripulado (VANT) como plataforma para a tomada de fotografias aéreas para o mapeamento planialtimétrico de erosão situada em zona urbana. Além disso, analisou-se a necessidade de utilização ou não de pontos de controle de campo para a geração de Modelo Digital de Superfície (MDS) e ortomosaico
como instrumentos para examinar o processo erosivo. Apesar da grande variação da atitude da aeronave durante a obtenção das fotografias aéreas que compõem o bloco aerofotogramétrico, foi possível gerar o MDS e o ortomosaico com ou sem pontos de controle. Este estudo foi realizado em duas erosões urbanas, uma situada em Goiânia-GO, no Setor Fonte Nova/Córrego do Capim, e a outra em Silvânia-GO, denominada de Lava-Pés. Toda a geração dos MDS, Modelo Digital de Terreno (MDT) e ortomosaico foram realizados no programa Agisoft PhotoScan, em processamento semiautomático (i.e., com pontos de controle) e automático (i.e., sem pontos de controle). Os ortomosaicos gerados sem pontos de controle apresentaram rotação, translação e escala diferente dos gerados com apoio. Ademais, os MDS gerados sem pontos de controle apresentaram elevação ou rebaixamento da superfície de referência em relação aos gerados com controle. Ressalta-se, ainda, que essas discrepâncias não foram constantes. Ao realizar a conversão automática do MDS para o MDT, percebeu-se que o programa não foi capaz de eliminar a vegetação arbustiva localizada no interior da erosão. As vegetações arbórea, arbustiva ou rasteira (gramíneas) impedem a correta delimitação da erosão para o cálculo do volume. Porém, a diferença dos MDS gerados entre duas épocas distintas propicia identificar as alterações ocorridas nesse intervalo de tempo nas regiões sem cobertura vegetal. O uso de pontos de controle foi essencial para garantir a orientação, a escala e o plano de referência nos produtos gerados a partir das fotografias aéreas e, assim, avaliar as modificações da erosão. Por fim, o VANT pode ser utilizado como plataforma para a tomada de fotografias aéreas para gerar produtos cartográficos que possibilitem o mapeamento e as avaliações das erosões, sobretudo em áreas urbanas.
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