The Florida Everglades ecosystem is experiencing increasing threats from anthropogenic modification of water flow, spread of invasive species, sea level rise (SLR), and more frequent and/or intense hurricanes. Restoration efforts aimed at rehabilitating these ongoing and future disturbances are currently underway through the implementation of the Comprehensive Everglades Restoration Plan (CERP). Efficacy of these restoration activities can be further improved with accurate and site-specific information on the current state of the coastal wetland habitats. In order to produce such assessments, digital datasets of the appropriate accuracy and scale are needed. These datasets include orthoimagery to delineate wetland areas and map vegetation cover as well as accurate 3-dimensional (3-D) models to characterize hydrology, physiochemistry, and habitat vulnerability. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

The ultimate goal of the development of aerial photogrammery is to acquire rapidly and accurately the ground measurements. However, traditional photogrammetric technologies, particularly in the continuous digital images stitching technique, is still very limited. In the past, the ground control points were used as the references for the image registration, however, it is very time and resource consuming, as well as human visual capability constraint. Accuracy and efficiency are two key factors which need to be enhanced to meet the practical requirement for aerial imageries stitching. The SIFT (Sale Invariant Feature Transform) algorithm was used in the computer vision to perform feature extraction in good condition. The extracted SIFT features are invariant to image scale, rotation, noise and change in illumination, and it is a robust and abundant feature extraction algorithm. SIFT algorithm extracts feature points from multi-scale space. For a large scale aerial image containing huge amount of image contents, it will spend a lot of time to extract features from imagery. Therefore, this study proposes a new method, called Inter-Grid Down-Sampling (IGDS) method, to reduce the image size and relative amount of image information to improve the computing efficiency. The correspondent extracted features are matched in the adjacent images with additional RANSAC outlier removal procedure to select correct and characteristic feature points. Finally the Hugin-Panorama Photo Stitching software is used to stitch all the continuous photogrammetric images for producing a panorama imagery of all flight lines. The experiment results indicate that sub-pixel accuracy for extracted feature points can be obtained when the down-sampling factor 3 was selected for the IGDS method, and it only needs half of the computing time. Compared to the Nearest-Neighbor Interpolation and Cubic Interpolation methods to reduce the image size, the IGDS method can increase more feature extraction efficiency without scarifying the location accuracy. When threshold value for SIFT was set between 0.4 to 0.6, we can achieve the largest correct matching rate. In addition, the RANSAC outlier removal procedure can effectively select the best matching feature points both in numbers and locations. For image stitching, the Hugin-panorama photo stitching software can effectively be used to match feature points and do geometric correction and color adjustment to obtain a consistent panorama imagery. Finally, the proposed method in this study can derive a low-variant in resolution and measurements significance for a stitching image from continuous aerial images.

Thesis (doctoral)--University of Hong Kong, 1988.

Luftbildbefliegungen unbemannt und bemannt sind aktuelle Technologien zur Erfassung der Umwelt. Die Interpretation der Produkte ist enorm vielseitig. Nicht immer werden jedoch die geometrischen Wünsche nach der Genauigkeit von Punkten, Linien und Flächen erfüllt. Im Vortrag werden die einzuhaltenden Regeln für genaue Messungen von Lage und Höhe aufgezeigt. Insbesondere die Höhenmessgenauigkeit erscheint als das Kriterium, um diese neuen Technologien fest in den Ingenieurwissenschaften zu verankern. Es werden Beispiele gezeigt, die Höhengenauigkeiten von 2-3 cm für größere Gebiete erzielt haben. Abschließend wird ein Ausblick bezüglich neuer Entwicklungen und neuer Sensorik der Glückauf Vermessung GmbH gegeben. / Aerial photography unmanned and manned are newer technologies for detecting the environment. The interpretation of the products is extremely versatile. Not always, however, the geometrical requirements are met by the accuracy of points, lines and areas. In the presentation, the rules to be observed for accurate measurements of position and height are shown. In particular, the height measurement accuracy appears as the criterion for these new technologies to anchor in the engineering sciences. Showing examples, the level of accuracy achieved by 2-3 cm for larger areas. An outlook on further developments in the Glückauf Vermessung GmbH is given.

Luftbildbefliegungen unbemannt und bemannt sind aktuelle Technologien zur Erfassung der Umwelt. Die Interpretation der Produkte ist enorm vielseitig. Nicht immer werden jedoch die geometrischen Wünsche nach der Genauigkeit von Punkten, Linien und Flächen erfüllt. Im Vortrag werden die einzuhaltenden Regeln für genaue Messungen von Lage und Höhe aufgezeigt. Insbesondere die Höhenmessgenauigkeit erscheint als das Kriterium, um diese neuen Technologien fest in den Ingenieurwissenschaften zu verankern. Es werden Beispiele gezeigt, die Höhengenauigkeiten von 2-3 cm für größere Gebiete erzielt haben. Abschließend wird ein Ausblick bezüglich neuer Entwicklungen und neuer Sensorik der Glückauf Vermessung GmbH gegeben. / Aerial photography unmanned and manned are newer technologies for detecting the environment. The interpretation of the products is extremely versatile. Not always, however, the geometrical requirements are met by the accuracy of points, lines and areas. In the presentation, the rules to be observed for accurate measurements of position and height are shown. In particular, the height measurement accuracy appears as the criterion for these new technologies to anchor in the engineering sciences. Showing examples, the level of accuracy achieved by 2-3 cm for larger areas. An outlook on further developments in the Glückauf Vermessung GmbH is given.

I det här examensarbetet undersöks möjligheten att använda UAS över begränsade områden när den nationella höjdmodellen skapad av Lantmäteriet ska uppdateras. Ämnet var ett förslag från Lantmäteriet och huvudsyftet var att testa om UAS kan användas som komplettering till traditionell flygfotografering. Det blir allt vanligare att använda UAS inom till exempel geomatiken, eftersom det är ett bra verktyg när ett snabbt och effektivt resultat krävs. Lantmäteriet använder flygburen laserskanning vid genereringen av nationella höjdmodellen och den uppdateras med traditionell flygfotografering. Andra aspekter som undersökts i detta examensarbete var vilken mätosäkerhet kan uppnås med UAS vid framställandet av en DHM, vilken skillnad i lägesosäkerhet finns mellan studiens punktmoln jämfört med nationella höjdmodellen, samt mot punktmolnet genererat från traditionell flygfotografering och den ekonomiska aspekten vid användning av UAS. Detta utfördes genom att samla in data med hjälp av UAS över Furuvik, Gävle. Flyghöjden var 88 m över ett område på ca 1 ha. Därefter skapades en höjdmodell som kontrollerades enligt den tekniska specifikationen SIS-TS 21144:2013. I examensarbetet jämfördes punktmolnet som genererades från flygfoton tagna med UAS mot nationella höjdmodellen. Osäkerheten för den genererade höjdmodellen vid användandet av UAS visade ett bra resultat i höjd med en standardosäkerhet på 0,015 m. Punktmolnet genererat från Lantmäteriets bildmatchning låg 0,315-0,392 m under studiens punktmoln medan punktmolnet från laserskanningen låg 0,014-0,155 m över. Resultatet visade att användning av UAS är väldigt kostnadseffektivt när den nationella höjdmodellen över begränsade områden ska uppdateras. Det rekommenderas därför för Lantmäteriet att använda UAS för detta ändamål. Det blir mer än väl godkänt resultat och kostnaden är liten med tanke på resultatet, d.v.s. en metod för att verkligen kunna ajourhålla nationella höjdmodellen och komplettera traditionell flygfotografering över begränsade områden. Med denna metod slipper de vänta på att den traditionella flygfotograferingen ska ske. Tekniken går hela tiden framåt och inom en snar framtid kommer även laserskanning kunna ske med UAS. Det skulle vara intressant att se resultat av den metoden. Intressant skulle även vara att se om det i framtiden går att utesluta flygsignalering och verkligen kunna använda direkt georeferering för att spara tid ute i fält. / In this thesis we are going to investigate possibility of using UAS, over small areas, for updating national elevation model produced by the National Land Survey of Sweden. The subject of the thesis was proposed by the National Land Survey of Sweden. One of the main objectives of the study was to test if UAS can be used as a complement to traditional aerial photo. The use of UAS has increased over the years within for example geomatics, because it is a great tool when quick and effective results are required. The National Land Survey of Sweden uses airborne laser scanning to generate the national elevation model. The elevation model is then updated by traditional aerial photogrammetry. Other objectives that have been investigated in this study are what uncertainty can be expected with UAS when generating a DEM, the differences in uncertainty between the point cloud generated in this study to the national height model and to the point cloud generated from the traditional photogrammetry and the economic aspects when using UAS. For this purpose data was collected by UAS in Furuvik, Gävle. The flight height was 88 m over the area of about 1 ha. Then a DEM was created and controlled according to the technical specification SIS-TS 21144:2013. In this thesis a comparison between the point cloud generated in this study and the national elevation model has been performed. Uncertainty of the produced DEM using UAS showed very good result in height with a standard deviation of 0.015 m. The point cloud generated from the traditional photogrammetry was 0.315-0.392 m below the point cloud generated in this study, while the point cloud from laser scanning was 0.014-0.155 m above. The results showed that using UAS are very cost-effective to update the national elevation model. It is advisable for the National Land Survey of Sweden to update the national height model over small areas with this method. There will be more than efficient and the costs are small considering the result. In other word this method is to recommend when updating the national elevation model and can be used as a complement to traditional photogrammetry within limited areas. With this method, they will not have to wait for the traditional aerial photography to take place. The technology is constantly moving forward and in the near future laser scanning with UAS will occur. It would be interesting to see the results of that method. It would also be interesting to see if it is possible to exclude the ground control points, and really be able to use direct georeferencing to save time in the field.

Resource managers frequently require moderate to high resolution imagery within short turnaround periods for use in a GIS-based management system. These spatial data can greatly enhance their ability to make timely, cost-saving decisions and recommendations. MBB Consulting Engineers, Inc., of Pietermaritzburg, South Africa had for many years made use of airborne videography to provide the imagery for several resource-based applications. Applications included detailed land use mapping in various South African river catchments and identification, density classification and mapping of alien vegetation. While the system was low cost and easy to operate, MBB had found that their system was inherently limited, particularly by its lack of automation and poor spatial resolution. This project was started because of a need to address these limitations and provide an airborne remote sensing system that was more automated and could produce higher resolution imagery than the existing system. In addition, the overall cost and time required to produce a map of the resource of interest needed to be reduced. The system developed in this project aimed to improve upon the pre-flight planning and in-flight image acquisition aspects of the existing system. No new post-flight image processing procedures were developed, but possible future refinement of the post-flight image processing routine was considered throughout the development of the system. A pre-flight planning software package was developed that could quickly and efficiently calculate the positions offlight lines and photographs or images with a minimum of user input. The in-flight image acquisition setup developed involved the integration of a high resolution digital still camera, a Global Positioning System (GPS), and camera control software. The use of the rapidly developing and improving technology of a digital still camera was considered to be a better alternative than a video graphic or traditional film camera system for a number of reasons. In particular, digital still cameras produce digital imagery without the need for development and scanning of aerial photographs or frame grabbing of video images. Furthermore, the resolution of current digital still cameras is already significantly better than that of video cameras and is rivalling the resolution of 35rnm film. The system developed was tested by capturing imagery of an urban test area. The images obtained were then rectified using photogrammetric techniques. Results obtained were promising with planimetric accuracies of 5 to 1 Om being obtained. From this test it was concluded that for high accuracy applications involving numerous images, use would be made of softcopy photogrammetric software to semi-automatically position and rectify images, while for applications requiring fewer images and lower accuracy, images could be rectified using the simpler technique of assigning GCPs for each image from scanned orthophotos. / Thesis (MSc.)- University of Natal,Pietermaritzburg, 2000.

GIS has been utilized in cultural resources management for decades, yet its application has been largely isolated to predicting the occurrence of archaeological sites. Federal and State agencies are required to protect archaeological sites that are discovered on their lands, but their resources and personnel are very limited. A new methodology is evaluated that uses modern light detection and ranging (LiDAR) and historic aerial photogrammetry to create digital terrain models (DTMs) capable of identifying sites that are most at risk of damage from changes in terrain. Results revealed that photogrammetric modeling of historic aerial imagery, with limitations, can be a useful decision making tool for cultural resources managers to prioritize conservation and monitoring efforts. An attempt to identify key environmental factors that would be indicative of future topographic changes did not reveal conclusive results. However, the methodology proposed has the potential to add an affordable temporal dimension to future digital terrain modeling and land management. Furthermore, the methods have global applicability because they can be utilized in any region with an arid environment.

Letecká fotogrammetrie v oblasti bezpilotních systémů představuje rychle rozvíjející se obor nalézající uplatnění napříč nejen průmyslovými odvětvími. Široce rozšířená metoda nepřímého georeferencování založená na vlícovacích bodech sice dosahuje vysoké přesnosti a spolehlivosti, v některých speciálních aplikacích nicméně není použitelná. Tato disertační práce se zabývá vývojem senzorického systému pro přímé georeferencování aplikovatelného na malých bezpilotních prostředcích a dále také návrhem vhodných kalibračních metod a testováním přesnosti. Významná část práce je věnována novým oblastem, kde může navržený systém pomoci eliminovat bezpečnostní rizika spojená s daným prostředím. V tomto kontextu byl systém testován v reálných podmínkách při mapování sněhu v horských oblastech a při robotickém mapování radiace.

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