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Journal articles on the topic 'Photogrammetric Triangulation'
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1
Re, C., S. Robson, R. Roncella, and M. Hess. "Metric Accuracy Evaluation of Dense Matching Algorithms in Archeological Applications." Geoinformatics FCE CTU 6 (December 21, 2011): 275–82. http://dx.doi.org/10.14311/gi.6.34.
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In the cultural heritage field the recording and documentation of small and medium size objects with very detailed Digital Surface Models (DSM) is readily possible by through the use of high resolution and high precision triangulation laser scanners. 3D surface recording of archaeological objects can be easily achieved in museums; however, this type of record can be quite expensive. In many cases photogrammetry can provide a viable alternative for the generation of DSMs. The photogrammetric procedure has some benefits with respect to laser survey. The research described in this paper sets out to verify the reconstruction accuracy of DSMs of some archaeological artifacts obtained by photogrammetric survey. The experimentation has been carried out on some objects preserved in the Petrie Museum of Egyptian Archaeology at University College London (UCL). DSMs produced by two photogrammetric software packages are compared with the digital 3D model obtained by a state of the art triangulation color laser scanner. Intercomparison between the generated DSM has allowed an evaluation of metric accuracy of the photogrammetric approach applied to archaeological documentation and of precision performances of the two software packages.
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He, Hai Qing, and Peng Gen Cheng. "Robust and Efficient Solution to Absolute Orientation in Low-Altitude Photogrammetry." Applied Mechanics and Materials 631-632 (September 2014): 456–61. http://dx.doi.org/10.4028/www.scientific.net/amm.631-632.456.
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Absolute orientation is a classic photogrammetric task for recovering the transformation relationship between two coordinate systems. In low-altitude photogrammetric field, arbitrary coordinate system in the network of aerial triangulation is spatial auxiliary coordinate system, which is quite different from ground photogrammetric coordinate. So the commonly used solution to absolute orientation with simplified parameters is unsuitable for low-altitude photogrammetry. In this paper, a novel solution of absolute orientation is proposed, the initial parameters of absolute orientation can be solved by the formula using centroids of coordinates instead of simplified parameters, then the parameters of absolute orientation are iteratively refined by Levenberg-Marquardt algorithm. Experimental results show that the solution is effective and practical. It may be suitable to implement absolute orientation in low-altitude photogrammetry.
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Kumar, Umesh. "Replacement of Professional Photogrammetric Workstations with Low Cost or Free of Charge Photogrammetric Software and Services for Image Triangulation and Image Matching." Journal on Geoinformatics, Nepal 12 (October 31, 2013): 42–48. http://dx.doi.org/10.3126/njg.v12i0.9072.
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In the modern context of digital technology in the field of surveying and mapping, the technique of digital photogrammetry plays crucial role in all steps of mapping. There are some very expensive as well as low cost and free softwares are available in the market for professional photogrammetric work stations. The image triangulation and image matching is one of the very important steps of photogrammetry for which LPS as a commercial software is available in market. There are some low cost and free software as 123D Catch and Patch Boased Multi View Stereo Softwear (PMVS) also available. So, this paper mainly deals with the accuracy as well as the performance of those software for aerial triangulation and image matching for airborne image data to substitute commercial software for photogrammetric workstations. The accuracy assessment of image orientation, points cloud as well as DSM generated from those points cloud are also performed and compared with all products of LPS as commercial software. Nepalese Journal on Geoinformatics -12, 2070 (2013AD): 42-48
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Sužiedelytė-Visockienė, Jūratė. "IMPROVEMENT OF RAILWAY TOPOGRAPHIC PLANS UPDATING TECHNOLOGIES." TRANSPORT 21, no. 2 (June 30, 2006): 119–22. http://dx.doi.org/10.3846/16484142.2006.9638052.
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Peculiar technologies on the update of topographic map linear objects to scale 1:500–1:2000 are presented. Due to that resulted peculiarities make aerial photographs, carrying out digital aerial triangulation, renewing the topographical plan. The article deals with the submitted example of the topographic plan exhibiting the renovated railway in the city of Vilnius. The updating has been made on the aerial photograph on 1:4000 scale with the photogrammetric instrument PlaniComp P3. The objects possessing no identification in photogrammetry are measured by means of a geodetic method. The redacting varied objects in a database are drawn with AutoCadsoftware. On the basis of this work it is possible to state that for fast and exact updating of topographic plans a progressive photogrammetric method is recommended. It is advised the edition data base to be made by the same operator who made photogrammetric work. The objects are visible in an aerial photo, but no identifying photogrammetry should be applied locally. Digital, renewed data are necessary for drawing up geo information systems (GIS) of the railway, to be able to make fast decisions of urgent problems.
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Shin, Sung Woong, Ayman F. Habib, Mwafag Ghanma, Changjae Kim, and Eui-Myoung Kim. "Algorithms for Multi-sensor and Multi-primitive Photogrammetric Triangulation." ETRI Journal 29, no. 4 (August 3, 2007): 411–20. http://dx.doi.org/10.4218/etrij.07.0106.0268.
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Fraser, Clive S. "Automated Processes in Digital Photogrammetric Calibration, Orientation, and Triangulation." Digital Signal Processing 8, no. 4 (October 1998): 277–83. http://dx.doi.org/10.1006/dspr.1998.0321.
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Altuntas, C. "TRIANGULATION AND TIME-OF-FLIGHT BASED 3D DIGITISATION TECHNIQUES OF CULTURAL HERITAGE STRUCTURES." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2021 (June 28, 2021): 825–30. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2021-825-2021.
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Abstract. This study aims to introduce triangulation and ToF measurement techniques used in three-dimensional modelling of cultural heritages. These measurement techniques are traditional photogrammetry, SfM approach, laser scanning and time-of-flight camera. The computer based approach to photogrammetric measurement that is named SfM creates dense point cloud data in a short time. It is low-cost and very easy to application. However traditional photogrammetry needs a huge effort for creating 3D wire-frame model. On the other hand active measurement techniques such as terrestrial laser scanner and time-of-flight camera have also been used in three-dimensional modelling for more than twenty years. Each one has specific accuracy and measurement effectiveness. The large or small structures have different characters, and require proper measurement configurations. In this study, after these methods are introduced, their superior and weak properties in cultural heritage modelling to make high accuracy, high density and labour and cost effective measurement.
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Jianming, Chen. "Map of the Mount Gongga Glacier: A Combination of Terrestrial and Aerial Photogrammetry." Annals of Glaciology 8 (1986): 34–36. http://dx.doi.org/10.1017/s0260305500001099.
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For use in glaciological research, between 1982 and 1984, we succeeded in surveying and mapping the Mount Gongga Glacier, on a scale of 1:25 000, by means of a combination of terrestrial and aerial photogrammetry. This paper describes the method in detail. In the survey area, we set up an independent, triangulation network, with microwave distance measurement, and two, independent, straight-line traverses, for basic control. Control points were observed by intersection. The terrestrial, photogrammetric baselines were projected and corrected into distances on the. plane of the map. Terrestrial photography accounted for the majority of the photographs of the survey area. Surveying and mapping of planimetrie and topographic features were completed on a stereo-autograph, using plates mainly from terrestrial photogrammetry. Where these data were insufficient, they were supplemented by aerial photography, plotted on a photographic plotting instrument. Orientation points of the aerial photographs were established by terrestrial, photogrammetric analysis and located on the map by an optical, mechanical method. The practical result showed that a combination of terrestrial and aerial photogrammetry, in mapping a high, mountain, glacier area, on a large scale, is more feasible and flexible than other methods and more economical as well.
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Jianming, Chen. "Map of the Mount Gongga Glacier: A Combination of Terrestrial and Aerial Photogrammetry." Annals of Glaciology 8 (1986): 34–36. http://dx.doi.org/10.3189/s0260305500001099.
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For use in glaciological research, between 1982 and 1984, we succeeded in surveying and mapping the Mount Gongga Glacier, on a scale of 1:25 000, by means of a combination of terrestrial and aerial photogrammetry. This paper describes the method in detail.In the survey area, we set up an independent, triangulation network, with microwave distance measurement, and two, independent, straight-line traverses, for basic control. Control points were observed by intersection. The terrestrial, photogrammetric baselines were projected and corrected into distances on the. plane of the map.Terrestrial photography accounted for the majority of the photographs of the survey area. Surveying and mapping of planimetrie and topographic features were completed on a stereo-autograph, using plates mainly from terrestrial photogrammetry. Where these data were insufficient, they were supplemented by aerial photography, plotted on a photographic plotting instrument. Orientation points of the aerial photographs were established by terrestrial, photogrammetric analysis and located on the map by an optical, mechanical method.The practical result showed that a combination of terrestrial and aerial photogrammetry, in mapping a high, mountain, glacier area, on a large scale, is more feasible and flexible than other methods and more economical as well.
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Damian Wierzbicki and Kamil Krasuski. "Determining the Elements of Exterior Orientation in Aerial Triangulation Processing Using UAV Technology." Communications - Scientific letters of the University of Zilina 22, no. 1 (January 2, 2020): 15–24. http://dx.doi.org/10.26552/com.c.2020.1.15-24.
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Unmanned Aerial Vehicles (UAVs) are still an interesting and current research topic in photogrammetry. An important issue in this area is determining the elements of exterior orientation of image data acquired at low altitudes. The article presents selected mathematical methods (TGC, TIC, TAD) of estimating elements of exterior orientation for image data obtained at low altitudes. The measurement data for the experimental test were recorded by the Unmanned Aerial Vehicle platform Trimble UX-5. In the framework of the test photogrammetric flight, the authors obtained 506 images and navigation data specifying the position and orientation of the Unmanned Aerial Vehicle. As a result of the research, it is proven possible to show the usefulness of the mathematical models (TGC, TIC, TAD) in estimation of elements of exterior orientation.
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Merkle, D., A. Schmitt, and A. Reiterer. "SENSOR EVALUATION FOR CRACK DETECTION IN CONCRETE BRIDGES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 14, 2020): 1107–14. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-1107-2020.
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Abstract. Bridges are one of the most critical traffic infrastructure objects, therefore it is necessary to monitor them at regular intervals. Nowadays, this monitoring is made manually by visual inspection. In recent projects, the authors are developing automated crack detection systems to support the inspector. In this pre-study, different sensors, like different camera systems for photogrammetry, a laser scanner, and a laser triangulation system are evaluated for crack detection based on a defined required minimum crack width of 0.2 mm. The used test object is a blasted concrete plate, sized 70 cm × 70 cm × 5 cm and placed in an outdoor environment. The results of the data acquisition with the different sensors are point clouds, which make the results comparable. The point cloud from the chosen laser scanner is not sufficient for the required crack width even at a low speed of 1 m/s. The RGB or intensity information of the photogrammetric point clouds, even based on a low-cost smartphone camera, contain the targeted cracks. The authors advise against using only the 3D information of the photogrammetric point clouds for crack detection due to noise. The laser triangulation system delivers the best results in both intensity and 3D information. The low weight of camera systems makes photogrammetry to the preferred method for an unmanned aerial vehicle (UAV). In the future, the authors aim for crack detection based on the 2D images, automated by using machine learning, and crack localisation by using structure from motion (SfM) or a positioning system.
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Karagiannis, Georgios, Francesc Antón Castro, and Darka Mioc. "AUTOMATED PHOTOGRAMMETRIC IMAGE MATCHING WITH SIFT ALGORITHM AND DELAUNAY TRIANGULATION." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences III-2 (June 2, 2016): 23–28. http://dx.doi.org/10.5194/isprsannals-iii-2-23-2016.
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An algorithm for image matching of multi-sensor and multi-temporal satellite images is developed. The method is based on the SIFT feature detector proposed by Lowe in (Lowe, 1999). First, SIFT feature points are detected independently in two images (reference and sensed image). The features detected are invariant to image rotations, translations, scaling and also to changes in illumination, brightness and 3-dimensional viewpoint. Afterwards, each feature of the reference image is matched with one in the sensed image if, and only if, the distance between them multiplied by a threshold is shorter than the distances between the point and all the other points in the sensed image. Then, the matched features are used to compute the parameters of the homography that transforms the coordinate system of the sensed image to the coordinate system of the reference image. The Delaunay triangulations of each feature set for each image are computed. The isomorphism of the Delaunay triangulations is determined to guarantee the quality of the image matching. The algorithm is implemented in Matlab and tested on World-View 2, SPOT6 and TerraSAR-X image patches.
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Karagiannis, Georgios, Francesc Antón Castro, and Darka Mioc. "AUTOMATED PHOTOGRAMMETRIC IMAGE MATCHING WITH SIFT ALGORITHM AND DELAUNAY TRIANGULATION." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences III-2 (June 2, 2016): 23–28. http://dx.doi.org/10.5194/isprs-annals-iii-2-23-2016.
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An algorithm for image matching of multi-sensor and multi-temporal satellite images is developed. The method is based on the SIFT feature detector proposed by Lowe in (Lowe, 1999). First, SIFT feature points are detected independently in two images (reference and sensed image). The features detected are invariant to image rotations, translations, scaling and also to changes in illumination, brightness and 3-dimensional viewpoint. Afterwards, each feature of the reference image is matched with one in the sensed image if, and only if, the distance between them multiplied by a threshold is shorter than the distances between the point and all the other points in the sensed image. Then, the matched features are used to compute the parameters of the homography that transforms the coordinate system of the sensed image to the coordinate system of the reference image. The Delaunay triangulations of each feature set for each image are computed. The isomorphism of the Delaunay triangulations is determined to guarantee the quality of the image matching. The algorithm is implemented in Matlab and tested on World-View 2, SPOT6 and TerraSAR-X image patches.
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Dalmolin, Quintino, John Alejandro Fierro Sanhueza, Edson Aparecido Mitishita, and Daniel Rodrigues Dos Santos. "Photogrammetric control points from airborne laser scanner." Revue Française de Photogrammétrie et de Télédétection, no. 198-199 (April 21, 2014): 39–45. http://dx.doi.org/10.52638/rfpt.2012.70.
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Cet article présente une méthodologie d’extraction semi-automatique de points d’appui pour la phototriangulation à partir d’images d’intensité laser. Les points d’appui sont déterminés par l’intersection de facettes planes reconstruites à partir des points d’un levé laser aéroporté. L’objectif est de vérifier la possibilité de substituer les points ainsi obtenus à des points qui seraient mesurés directement sur le terrain, par exemple au moyen d’un récepteur GPS. Les points laser sont traités de manière à permettre la reconstrtruction des facettes places correspondant aux toits des maisons, édifices et autres constructions, par une méthode semi-automatique. L’identification et l’extraction de cette facettes se sont appuyées sur une triangulation de Delaunay et sur l’analyse des vecteurs normaux des triangles qui la constituent. Pour tester cette méthode, on a réalisé une photo-triangulation avec une compensation par faisceaux basée sur les points issus du relevé laser, des points mesurész sur le terrain par GPS servant de points de contrôle. Un bloc photogrammétrique constitué de 6 images acquises par une caméra non métrique a été utilisé pour ces tests. L’analyse et la comparaison des résultats permettent de recommander cette méthode.
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SUBA, Elemer Emanuel, Tudor SĂLĂGEAN, Ioana POP, Florica MATEI, Jutka DEAK, Iulia COROIAN, and Diana FICIOR. "Using Photogrammetric UAV Measurements as Support for Classical Topographical Measurements in Order to Obtain the Topographic Plan for Urban Areas." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Horticulture 74, no. 2 (November 26, 2017): 197. http://dx.doi.org/10.15835/buasvmcn-hort:0026.
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This article aims to highlight the benefits of UAV photogrammetric measurements in addition to classical ones. It will also deal with the processing and integration of the point cloud, respectively the digital elevation model in topo-cadastral works. The main purpose of this paper is to compare the results obtained using the UAV photogrammetric measurements with the results obtained by classical methods. It will briefly present the classical measurements made with the total station. In the present project, the closed-circuit traverse and the supported on the endings traverse were made using known coordinate points. Determining the coordinates of the points used for the traverses was done by GNSS methods. The area on which the measurements were made is 67942m2 and is covered by 31 determined station points. From these points, 13 were used as ground control points, respectively components of the aero-triangulation network and 17 points were used to control the obtained results by comparing their coordinates obtained by classical methods with those obtained by the UAV photogrammetric method. It was intended that the constraint points of the aero triangulation to be uniformly distributed on the studied surface.
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Kurkov, V. M., and A. S. Kiseleva. "DEM ACCURACY RESEARCH BASED ON UNMANNED AERIAL SURVEY DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2020 (August 22, 2020): 1347–52. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2020-1347-2020.
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Abstract. Currently, digital elevation models (DEM) created by photogrammetric method based on unmanned aerial survey data are becoming an increasingly popular product. They are used in various areas of human activity related to modelling and analysis of terrain, namely: topography, engineering and geodetic surveys, surveying, archaeology, geomorphology, etc. The accuracy of digital surface and terrain models obtained by the photogrammetric method depends on the accuracy of aerial triangulation and dense point cloud from a number of overlapping images. In turn, the accuracy of the aerial triangulation is determined by the accuracy of the measurements of the tie points, GCP's / check points and the intersection geometry. When constructing a dense cloud using the SGM algorithm, the quality of the surface/terrain model depends not only on the accuracy of point identification, but also on filtering outliers and rejecting unreliable measurements. This article presents the results of evaluating the accuracy of creating a digital elevation model obtained by various unmanned aerial survey systems on a single test area.
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Walker, Stewart, and Arleta Pietrzak. "Remote measurement methods for 3-D modeling purposes using BAE Systems’ Software." Geodesy and Cartography 64, no. 1 (June 1, 2015): 113–24. http://dx.doi.org/10.1515/geocart-2015-0009.
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Abstract Efficient, accurate data collection from imagery is the key to an economical generation of useful geospatial products. Incremental developments of traditional geospatial data collection and the arrival of new image data sources cause new software packages to be created and existing ones to be adjusted to enable such data to be processed. In the past, BAE Systems’ digital photogrammetric workstation, SOCET SET®, met fin de siècle expectations in data processing and feature extraction. Its successor, SOCET GXP®, addresses today’s photogrammetric requirements and new data sources. SOCET GXP is an advanced workstation for mapping and photogrammetric tasks, with automated functionality for triangulation, Digital Elevation Model (DEM) extraction, orthorectification and mosaicking, feature extraction and creation of 3-D models with texturing. BAE Systems continues to add sensor models to accommodate new image sources, in response to customer demand. New capabilities added in the latest version of SOCET GXP facilitate modeling, visualization and analysis of 3-D features.
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Zhang, Yunsheng, Chi Zhang, Siyang Chen, and Xueye Chen. "Automatic Reconstruction of Building Façade Model from Photogrammetric Mesh Model." Remote Sensing 13, no. 19 (September 22, 2021): 3801. http://dx.doi.org/10.3390/rs13193801.
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Three-dimensional (3D) building façade model reconstruction is of great significance in urban applications and real-world visualization. This paper presents a newly developed method for automatically generating a 3D regular building façade model from the photogrammetric mesh model. To this end, the contour is tracked on irregular triangulation, and then the local contour tree method based on the topological relationship is employed to represent the topological structure of the photogrammetric mesh model. Subsequently, the segmented contour groups are found by analyzing the topological relationship of the contours, and the original mesh model is divided into various components from bottom to top through the iteration process. After that, each component is iteratively and robustly abstracted into cuboids. Finally, the parameters of each cuboid are adjusted to be close to the original mesh model, and a lightweight polygonal mesh model is taken from the adjusted cuboid. Typical buildings and a whole scene of photogrammetric mesh models are exploited to assess the proposed method quantitatively and qualitatively. The obtained results reveal that the proposed method can derive a regular façade model from a photogrammetric mesh model with a certain accuracy.
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He, Fangning, Tian Zhou, Weifeng Xiong, Seyyed Hasheminnasab, and Ayman Habib. "Automated Aerial Triangulation for UAV-Based Mapping." Remote Sensing 10, no. 12 (December 4, 2018): 1952. http://dx.doi.org/10.3390/rs10121952.
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Accurate 3D reconstruction/modelling from unmanned aerial vehicle (UAV)-based imagery has become the key prerequisite in various applications. Although current commercial software has automated the process of image-based reconstruction, a transparent system, which can be incorporated with different user-defined constraints, is still preferred by the photogrammetric research community. In this regard, this paper presents a transparent framework for the automated aerial triangulation of UAV images. The proposed framework is conducted in three steps. In the first step, two approaches, which take advantage of prior information regarding the flight trajectory, are implemented for reliable relative orientation recovery. Then, initial recovery of image exterior orientation parameters (EOPs) is achieved through either an incremental or global approach. Finally, a global bundle adjustment involving Ground Control Points (GCPs) and check points is carried out to refine all estimated parameters in the defined mapping coordinate system. Four real image datasets, which are acquired by two different UAV platforms, have been utilized to evaluate the feasibility of the proposed framework. In addition, a comparative analysis between the proposed framework and the existing commercial software is performed. The derived experimental results demonstrate the superior performance of the proposed framework in providing an accurate 3D model, especially when dealing with acquired UAV images containing repetitive pattern and significant image distortions.
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Gressin, A., J. Vallet, and M. Bron. "ABOUT PHOTOGRAMMETRIC UAV-MAPPING: WHICH ACCURACY FOR WHICH APPLICATION?" ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 14, 2020): 1081–89. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-1081-2020.
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Abstract. UAV surveys have become more and more popular over the last few years, driven by manufacturers and software suppliers who promise high accuracy at low cost. But, what are the real possibilities offered by this kind of sensor? In this article, we investigate in detail the possibilities offered by photogrammetric UAV mapping solutions through numerous practical experiments and compare them to a reference high grade LiDAR-Photogrammetric acquisition. This paper first focuses on aerial triangulation and dense matching accuracy comparison of different data acquisition units (2 types of camera) and processing softwares (1 open source and 2 proprietary softwares). Finally, the opportunities offered by these different approaches are studied in detail on standard aerial applications such as power lines detection, forest and urban areas mapping, in comparison with our reference dataset.
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Ioli, F., L. Pinto, and F. Ferrario. "LOW-COST DGPS ASSISTED AERIAL TRIANGULATION FOR SUB-DECIMETRIC ACCURACY WITH NON-RTK UAVS." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2021 (June 28, 2021): 25–32. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2021-25-2021.
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Abstract. The possibility of equipping UAVs with lightweight GNSS receivers in order to estimate the camera position within a photogrammetric block allows for a reduction of the number of Ground Control Points (GCP), saving time during the field work and decreasing operational costs. Additionally, this makes it possible to build photogrammetric models even in morphologically complex areas or in emergency situations. This work is proposing a non-intrusive and low-cost procedure to retrieve the coordinates of the camera projection centre with decimetric accuracy. The method was designed and tested with the quadcopter DJI Matrice 210 V2 drone equipped with a DJI ZENMUSE X5S camera and an Emlid reach M, a low-cost, single-frequency (L1) GNSS receiver. GNSS observations are post-processed in PPK in order to obtain the UAV trajectory. Synchronization between the camera and the GNSS receiver is achieved by looking at the camera triggering timestamps in flight telemetry data, without requiring an electronic connection between camera and the GNSS that may be troublesome with commercial UAVs. Two surveys were carried out, respectively to calibrate and validate the procedure. The validation test evidenced the possibility of obtaining the coordinates of the camera projection centres with decimetric accuracy. The centre of projections can then be employed for GNSS-assisted aerial triangulation as input of the bundle block adjustment. Provided that at least one GCP is used, it is possible to reach centimetric accuracy on the ground.
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Mulsow, C., H. G. Maas, and B. Hentschel. "OPTICAL TRIANGULATION ON INSTATIONARY WATER SURFACES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (June 15, 2016): 85–91. http://dx.doi.org/10.5194/isprs-archives-xli-b5-85-2016.
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The measurement of water surfaces is a key task in the field of experimental hydromechanics. Established techniques are usually gauge-based and often come with a large instrumental effort and a limited spatial resolution. The paper shows a photogrammetric alternative based on the well-known laser light sheet projection technique. While the original approach is limited to surfaces with diffuse reflection properties, the developed technique is capable of measuring dynamically on reflecting instationary surfaces. Contrary to the traditional way, the laser line is not observed on the object. Instead, using the properties of water, the laser light is reflected on to a set of staggered vertical planes. The resulting laser line is observed by a camera and measured by subpixel operators. A calibration based on known still water levels provides the parameters for the translation of image space measurements into water level and gradient determination in dynamic experiments. As a side-effect of the principle of measuring the reflected laser line rather than the projected one, the accuracy can be improved by almost a factor two. In experiments a standard deviation of 0.03 mm for water level changes could be achieved. The measuring rate corresponds to the frame rate of the camera. A complete measuring system is currently under development for the Federal Waterways Engineering and Research Institute (BAW). <br><br> This article shows the basic principle, potential and limitations of the method. Furthermore, several system variants optimised for different requirements are presented. Besides the geometrical models of different levels of complexity, system calibration procedures are described too. The applicability of the techniques and their accuracy potential are shown in several practical tests.
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Si youcef, K., I. Boukerch, F. Z. Belhouari, A. M. Seddiki, and B. Takarli. "THE IMPLEMENTATION OF A PHOTOGRAMMETRIC PROCEDURE FOR THE ADJUSTMENT OF THE OLD RASTER CADASTRAL PLANS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B4-2020 (August 24, 2020): 177–82. http://dx.doi.org/10.5194/isprs-archives-xliii-b4-2020-177-2020.
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Abstract. Algeria faces challenges of globalization. It classifies the establishment of the national general urban and rural territory cadastre as top priority. The National Cadastre Agency has implemented a policy aimed at improving the quality and accuracy of the resulting documentation, in order to widen the scope of the latter in the various fields.Since the launching of the first operations to establish the general cadastre of the national territory, the graphic cadastral documentation which was carried out based on aerial images (ortho-photographs or restitution plans) present mismatch either between the external borders or between the section plans that compose the communal (municipal) cadastral plane.This article describes one of the simultaneous plane adjustment techniques inspired by the aero triangulation used in photogrammetry. In a first step, we built the photogrammetric unit where we consider the cadastral planes as photogrammetric models. In a second step, the constructed units will be used to form a superstructure covering a very large area like in the photogrammetric block case. Finally, this superstructure is adjusted, where the discrepancies are reduces relatively between these section plans using Tie Points (TP) and absolutely by relying on an optimal number of Ground Control Points (GCP) in the terrain system suitably distributed on the block.This technique makes it possible to preserve the relationships between the data in a precise way and to guarantee the continuity in the acquisition of the data which can be added later. It also makes it possible to solve the problem of the overlap between the isolated section plans due to the non-optimal distribution, the insufficiency, or the absence of control points.The evaluation results obtained after the experiments report that the proposed adjustment technique is efficient to solve such a problem.
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Shmutter, B., and Y. Doytsher. "Matching a set of digitized cadastral maps." CISM journal 46, no. 3 (October 1992): 277–84. http://dx.doi.org/10.1139/geomat-1992-0029.
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Errors inherent in the digitizing process inevitably lead to variations in the locations of boundaries of neighboring cadastral blocks. It then becomes necessary to adjust the digitized data to compensate for discrepancies and discontinuities in the digitized cadastral information. For this purpose it is proposed that a procedure commonly used in aerial triangulation be adopted. Each map is regarded as an equivalent to a single photograph and a set of neighboring maps as a photogrammetric block. A system of appropriate equations is formed to adjust the “block”. Points lying on boundaries of adjacent cadastral blocks are the substitute for the transfer and tie points used in photogrammetry, and traverse or trigpoints available on the maps constitute the control data. The results of this procedure are: “orientation” data for each map to transform its content to the state plane coordinate system and adjusted coordinates of points positioned on boundaries shared by neighboring maps.
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Mulsow, C., H. G. Maas, and B. Hentschel. "OPTICAL TRIANGULATION ON INSTATIONARY WATER SURFACES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B5 (June 15, 2016): 85–91. http://dx.doi.org/10.5194/isprsarchives-xli-b5-85-2016.
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The measurement of water surfaces is a key task in the field of experimental hydromechanics. Established techniques are usually gauge-based and often come with a large instrumental effort and a limited spatial resolution. The paper shows a photogrammetric alternative based on the well-known laser light sheet projection technique. While the original approach is limited to surfaces with diffuse reflection properties, the developed technique is capable of measuring dynamically on reflecting instationary surfaces. Contrary to the traditional way, the laser line is not observed on the object. Instead, using the properties of water, the laser light is reflected on to a set of staggered vertical planes. The resulting laser line is observed by a camera and measured by subpixel operators. A calibration based on known still water levels provides the parameters for the translation of image space measurements into water level and gradient determination in dynamic experiments. As a side-effect of the principle of measuring the reflected laser line rather than the projected one, the accuracy can be improved by almost a factor two. In experiments a standard deviation of 0.03 mm for water level changes could be achieved. The measuring rate corresponds to the frame rate of the camera. A complete measuring system is currently under development for the Federal Waterways Engineering and Research Institute (BAW). <br><br> This article shows the basic principle, potential and limitations of the method. Furthermore, several system variants optimised for different requirements are presented. Besides the geometrical models of different levels of complexity, system calibration procedures are described too. The applicability of the techniques and their accuracy potential are shown in several practical tests.
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Kraft, T., M. Geßner, H. Meißner, H. J. Przybilla, and M. Gerke. "INTRODUCTION OF A PHOTOGRAMMETRIC CAMERA SYSTEM FOR RPAS WITH HIGHLY ACCURATE GNSS/IMU INFORMATION FOR STANDARDIZED WORKFLOWS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W4 (March 17, 2016): 71–75. http://dx.doi.org/10.5194/isprsarchives-xl-3-w4-71-2016.
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In this paper we present the evaluation of DLR’s modular airborne camera system MACS-Micro for remotely piloted aircraft system (RPAS) with a maximum takeoff weight (MTOW) less than 5kg. The main focus is on standardized calibration and test procedures as well as on standardized photogrammetric workflows as a proof of feasibility for this aerial camera concept. The prototype consists of an industrial grade frame imaging camera and a compact GNSS/IMU solution which are operated by an embedded PC. The camera has been calibrated pre- and post- flight using a three dimensional test field. The validation of the latest prototype is done by a traditional photogrammetric evaluation of an aerial survey using 39 ground control points. The results, concerning geometric and radiometric features of the present system concept as well as the quality of the aero triangulation, fulfill many of the aimed keyspecifications.
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Kraft, T., M. Geßner, H. Meißner, H. J. Przybilla, and M. Gerke. "INTRODUCTION OF A PHOTOGRAMMETRIC CAMERA SYSTEM FOR RPAS WITH HIGHLY ACCURATE GNSS/IMU INFORMATION FOR STANDARDIZED WORKFLOWS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W4 (March 17, 2016): 71–75. http://dx.doi.org/10.5194/isprs-archives-xl-3-w4-71-2016.
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In this paper we present the evaluation of DLR’s modular airborne camera system MACS-Micro for remotely piloted aircraft system (RPAS) with a maximum takeoff weight (MTOW) less than 5kg. The main focus is on standardized calibration and test procedures as well as on standardized photogrammetric workflows as a proof of feasibility for this aerial camera concept. The prototype consists of an industrial grade frame imaging camera and a compact GNSS/IMU solution which are operated by an embedded PC. The camera has been calibrated pre- and post- flight using a three dimensional test field. The validation of the latest prototype is done by a traditional photogrammetric evaluation of an aerial survey using 39 ground control points. The results, concerning geometric and radiometric features of the present system concept as well as the quality of the aero triangulation, fulfill many of the aimed keyspecifications.
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Kurczyński, Zdzisław, Krzysztof Bakuła, Magdalena Pilarska, and Wojciech Ostrowski. "The Problem of Using and Measurement of Identifiable Ground Control Points on High Resolution Aerial Images." Archives of Photogrammetry, Cartography and Remote Sensing 31, no. 1 (December 1, 2019): 135–44. http://dx.doi.org/10.2478/apcrs-2019-0009.
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Abstract This paper shows the influence of the selection of photogrammetric control points as natural, identifiable points instead of signalized, premarked control points on the results of aerial triangulation of high-resolution aerial images with GSD below 10 cm. In the experiment, different selections of controls were tested using point-type and linear-type points with measurement of their centre or corner. In the experiment, 2 blocks with GSD of 5 and 10 cm were selected using the same measurements in 4 tested approaches with sets of natural identifiable points used by comparing the result with the reference variant. The experiment proves the possibility of using natural controls instead of premarked controls for images of urban areas. This can significantly reduce the cost of photogrammetric missions in urban areas where it is easy to find uniquely identifiable control points that can be used for image orientation.
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Jeong, H. H., J. W. Park, J. S. Kim, and C. U. Choi. "Assessing the Accuracy of Ortho-image using Photogrammetric Unmanned Aerial System." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (June 6, 2016): 867–72. http://dx.doi.org/10.5194/isprsarchives-xli-b1-867-2016.
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Smart-camera can not only be operated under network environment anytime and any place but also cost less than the existing photogrammetric UAV since it provides high-resolution image, 3D location and attitude data on a real-time basis from a variety of built-in sensors. This study’s proposed UAV photogrammetric method, low-cost UAV and smart camera were used. The elements of interior orientation were acquired through camera calibration. The image triangulation was conducted in accordance with presence or absence of consideration of the interior orientation (IO) parameters determined by camera calibration, The Digital Elevation Model (DEM) was constructed using the image data photographed at the target area and the results of the ground control point survey. This study also analyzes the proposed method’s application possibility by comparing a Ortho-image the results of the ground control point survey. Considering these study findings, it is suggested that smartphone is very feasible as a payload for UAV system. It is also expected that smartphone may be loaded onto existing UAV playing direct or indirect roles significantly.
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Jeong, H. H., J. W. Park, J. S. Kim, and C. U. Choi. "Assessing the Accuracy of Ortho-image using Photogrammetric Unmanned Aerial System." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1 (June 6, 2016): 867–72. http://dx.doi.org/10.5194/isprs-archives-xli-b1-867-2016.
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Smart-camera can not only be operated under network environment anytime and any place but also cost less than the existing photogrammetric UAV since it provides high-resolution image, 3D location and attitude data on a real-time basis from a variety of built-in sensors. This study’s proposed UAV photogrammetric method, low-cost UAV and smart camera were used. The elements of interior orientation were acquired through camera calibration. The image triangulation was conducted in accordance with presence or absence of consideration of the interior orientation (IO) parameters determined by camera calibration, The Digital Elevation Model (DEM) was constructed using the image data photographed at the target area and the results of the ground control point survey. This study also analyzes the proposed method’s application possibility by comparing a Ortho-image the results of the ground control point survey. Considering these study findings, it is suggested that smartphone is very feasible as a payload for UAV system. It is also expected that smartphone may be loaded onto existing UAV playing direct or indirect roles significantly.
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Kadnichanskiy, S. A., M. V. Kurkov, V. M. Kurkov, and Aleksandr Chibunichev. "Certification testing hardware-and-software complex based on unmanned aerial vehicle “Geoscan 401”." Geodesy and Cartography 957, no. 3 (April 20, 2020): 32–38. http://dx.doi.org/10.22389/0016-7126-2020-957-3-32-38.
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The authors present the results of certification testing software-and-hardware complex on the basis of an unmanned aircraft (UAV) “Geoskan 401”, designed for aerial mapping. The substantiation of the need to assess the accuracy characteristics of the photogrammetric processing aerial photos results from the UAV is given. The composition of the complex, the parameters of the test site and the performed aerial photography are given, the order and method of testing are described. Assessment of the aerial triangulation accuracy, creation of a digital elevation model, digital orthophotos and coordinates of marked and unmarked characteristic points (natural contours) of land boundaries and building contours were carried out to confirm the compliance with the requirements of regulatory documents for the implementation of photogrammetric processing, maintenance of the state real estate cadastre and surveying. The values of the spatial data accuracy obtained with the help of a hardware-and-software complex confirm the possibility of using the “Geoskan 401” in real estate cadastre and surveying. Recommendations on the use of hardware and software complex for cadastral and mine surveying works are given.
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Ganz, Selina, Yannek Käber, and Petra Adler. "Measuring Tree Height with Remote Sensing—A Comparison of Photogrammetric and LiDAR Data with Different Field Measurements." Forests 10, no. 8 (August 16, 2019): 694. http://dx.doi.org/10.3390/f10080694.
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We contribute to a better understanding of different remote sensing techniques for tree height estimation by comparing several techniques to both direct and indirect field measurements. From these comparisons, factors influencing the accuracy of reliable tree height measurements were identified. Different remote sensing methods were applied on the same test site, varying the factors sensor type, platform, and flight parameters. We implemented light detection and ranging (LiDAR) and photogrammetric aerial images received from unmanned aerial vehicles (UAV), gyrocopter, and aircraft. Field measurements were carried out indirectly using a Vertex clinometer and directly after felling using a tape measure on tree trunks. Indirect measurements resulted in an RMSE of 1.02 m and tend to underestimate tree height with a systematic error of −0.66 m. For the derivation of tree height, the results varied from an RMSE of 0.36 m for UAV-LiDAR data to 2.89 m for photogrammetric data acquired by an aircraft. Measurements derived from LiDAR data resulted in higher tree heights, while measurements from photogrammetric data tended to be lower than field measurements. When absolute orientation was appropriate, measurements from UAV-Camera were as reliable as those from UAV-LiDAR. With low flight altitudes, small camera lens angles, and an accurate orientation, higher accuracies for the estimation of individual tree heights could be achieved. The study showed that remote sensing measurements of tree height can be more accurate than traditional triangulation techniques if the aforementioned conditions are fulfilled.
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Jeong, Hohyun, Hoyong Ahn, Dongyoon Shin, Yushin Ahn, and Chuluong Choi. "A Comparative Assessment of the Photogrammetric Accuracy of Mapping Using UAVs with Smart Devices." Photogrammetric Engineering & Remote Sensing 85, no. 12 (December 1, 2019): 889–97. http://dx.doi.org/10.14358/pers.85.12.889.
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This article evaluates <small>UAV</small> photogrammetry systems using smartphones and smart cameras. Image triangulation was conducted in accordance with interior orientation parameters, determined by camera self-calibration. Precise orthomosaic images and digital surface models were generated, and their accuracy was assessed using aerial and terrestrial lidar data. Digital surface models were used to estimate earthwork volumes and verify the suitability of <small>UAV</small> photogrammetry for use on construction sites. Georeferencing accuracy shows that the smart camera performs about twice as well as the smartphone with reference to checkpoints and polygon parts. Considering rolling shutter in the smartphone, it is possible to increase accuracy. Especially in inclined and rugged topography, the smartphone can benefit from applying the rolling-shutter method. Earthwork of volume error is often applied as a legal requirement for some countries, and our findings indicate that a smart camera with a drone can be effectively and economically used in earthworks.
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Li, J. M., C. R. Li, G. Z. Su, W. Li, L. L. Ma, and Y. K. Liu. "MAPPING SYSTEM AND PHOTOGRAMMETRIC PROCESSING METHOD FOR TETHERED BALLOON PLATFORM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W16 (September 17, 2019): 157–61. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w16-157-2019.
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<p><strong>Abstract.</strong> As a platform with the advantages of safety, wide altitude range and long flight time, tethered balloon has been used in archaeology, coastal, island mapping and other related fields. Tethered balloon is tied to the mooring system by tether rope, and often moves in a small range with the airflow, resulting in a very close distance between the camera stations. Due to the small base-to-height ratio, failure of relative orientation or poor quality of point cloud tend to appear frequently. In this paper, a mapping system for tethered balloon is introduced which consists of a wide-angle camera, two auxiliary orientation cameras, and a dual GNSS/IMU system. The wide-angle camera combined by five cameras provides a larger observation range. Two auxiliary orientation cameras installed at the end of extension rods are designed to increase the baseline. The system should be operated during the taking-off, hovering and landing stages of the tethered balloon, so as to take images of different altitudes. The system has been adopted in the first experimental flight in 2018 to perform island topographic survey. Data processing method was applied to test the effect of the system. The method that choosing wide-angle images of different heights, and auxiliary images at low-altitude can be used for aerial triangulation successfully, and obtain point cloud with good quality. The results showed that by adding auxiliary cameras and taking images of different heights for data processing, the problem of small intersection angle could be overcome to some extent.</p>
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Giagkas, Fotis, Petros Patias, and Charalampos Georgiadis. "Photogrammetric surveying forests and woodlands with UAVs: techniques for automatic removal of vegetation and digital terrain model production for hydrological applications." Journal of Unmanned Vehicle Systems 7, no. 1 (March 1, 2019): 1–20. http://dx.doi.org/10.1139/juvs-2016-0023.
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The purpose of this study is the photogrammetric survey of a forested area using unmanned aerial vehicles (UAV), and the estimation of the digital terrain model (DTM) of the area, based on the photogrammetrically produced digital surface model (DSM). Furthermore, through the classification of the height difference between a DSM and a DTM, a vegetation height model is estimated, and a vegetation type map is produced. Finally, the generated DTM was used in a hydrological analysis study to determine its suitability compared to the usage of the DSM. The selected study area was the forest of Seih-Sou (Thessaloniki). The DTM extraction methodology applies classification and filtering of point clouds, and aims to produce a surface model including only terrain points (DTM). The method yielded a DTM that functioned satisfactorily as a basis for the hydrological analysis. Also, by classifying the DSM–DTM difference, a vegetation height model was generated. For the photogrammetric survey, 495 aerial images were used, taken by a UAV from a height of ∼200 m. A total of 44 ground control points were measured with an accuracy of 5 cm. The accuracy of the aerial triangulation was approximately 13 cm. The produced dense point cloud, counted 146 593 725 points.
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Dorozhynskyy, O. L. ,., I. Z. Kolb, L. V. Babiy, and L. V. Dychko. "GEODESY, CARTOGRAPHY AND AERIAL PHOTOGRAPHY." GEODESY, CARTOGRAPHY AND AERIAL PHOTOGRAPHY 92,2020, no. 92 (December 24, 2020): 15–23. http://dx.doi.org/10.23939/istcgcap2020.92.015.
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Aim. Determination of the elements of external spatial orientation of the surveying systems at the moment of image acquisition is the fundamental task in photogrammetry. Principally, this problem is solving in two ways. The first way is direct positioning and measuring of directions of camera optical axis in the geodetic space with the help of GNSS/INS equipment. The second way is the analytical solution of the problem using a set of reference information (often such information is a set of ground control points whose geodetic positions are known with sufficient accuracy and which are reliably recognised on aerial images of the photogrammetric block). The authors consider the task of providing reference and control information using the second approach, which has a number of advantages in terms of reliability and accuracy of determining the unknown image exterior orientation parameters. It is proposed to obtain additional images of ground control points by the method of their auxiliary aerial photography using an unmanned aerial vehicle (UAV) on a larger scale compared to the scale of the images of the photogrammetric block. The aim of the presented work is the implementation of the method of creating reference points and experimental confirmation of its effectiveness for photogrammetric processing. Methods and results. For the entire realization of the potential of the analytical way to determine the elements of external orientation of images, it is necessary to have a certain number of ground control points (GCP) and to keep the defined scheme of their location on the photogrammetric block. As the main source of input data authors use UAV aerial images of the terrain, which are obtained separately from the block of aerial survey, and have a better geometric resolution and which clearly depict the control reference points. Application of such auxiliary images gives the possibility of automated transferring of the position of ground control point into images of the main photogrammetric block. In our interpretation, these images of ground control points and their surroundings on the ground are called "control reference images". The basis of the work is to develop a method for obtaining the auxiliary control reference images and transferring of position of GCP depicted on them into aerial or space images of terrain by means of computer stereo matching. To achieve this goal, we have developed a processing method for the creation of control reference images of aerial image or a series of auxiliary multi-scale aerial images obtained by a drone from different heights above the reference point. The operator identifies and measures the GCP once on the auxiliary aerial image of the highest resolution. Then there is an automatic stereo matching of the control reference image in the whole series of auxiliary images in succession with a decrease in the resolution and, ultimately, directly with the aerial images of photogrammetric block. On this stage there are no recognition/cursor targeting by the human operator, and therefore there are no discrepancies, errors or mistakes related to it. In addition, if to apply fairly large size of control reference images, the proposed method can be used on a low-texture terrain, and therefore deal in many cases without the physical marking of points measured by GNSS method. And this is a way to simplify and reduce the cost of photogrammetric technology. The action of the developed method has been verified experimentally to provide the control reference information of the block of archival aerial images of the low-texture terrain. The results of the experimental approbation of the proposed method give grounds to assert that the method makes it possible to perform geodetic reference of photogrammetric projects more efficiently due to the refusal of the physical marking of the area before aerial survey. The proposed method can also be used to obtain the information for checking the quality of photogrammetric survey for provision of check points. The authors argue that the use of additional equipment - UAV of semi-professional class to obtain control reference images is economically feasible. Scientific novelty and practical relevance. The results of approbation of the "control reference image" method with obtaining stereo pairs of aerial images with vertical placement of the base are presented for the first time. There was implemented the study of the properties of such stereo pairs of aerial images to obtain images of reference points. The effectiveness of including reference images in the main block of the digital aerial triangulation network created on UAV’s images is shown.
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Ye, L., and B. Wu. "PHOTOGRAMMETRIC POINT CLOUDS GENERATION IN URBAN AREAS FROM INTEGRATED IMAGE MATCHING AND SEGMENTATION." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-2/W4 (September 13, 2017): 279–85. http://dx.doi.org/10.5194/isprs-annals-iv-2-w4-279-2017.
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High-resolution imagery is an attractive option for surveying and mapping applications due to the advantages of high quality imaging, short revisit time, and lower cost. Automated reliable and dense image matching is essential for photogrammetric 3D data derivation. Such matching, in urban areas, however, is extremely difficult, owing to the complexity of urban textures and severe occlusion problems on the images caused by tall buildings. Aimed at exploiting high-resolution imagery for 3D urban modelling applications, this paper presents an integrated image matching and segmentation approach for reliable dense matching of high-resolution imagery in urban areas. The approach is based on the framework of our existing self-adaptive triangulation constrained image matching (SATM), but incorporates three novel aspects to tackle the image matching difficulties in urban areas: 1) occlusion filtering based on image segmentation, 2) segment-adaptive similarity correlation to reduce the similarity ambiguity, 3) improved dense matching propagation to provide more reliable matches in urban areas. Experimental analyses were conducted using aerial images of Vaihingen, Germany and high-resolution satellite images in Hong Kong. The photogrammetric point clouds were generated, from which digital surface models (DSMs) were derived. They were compared with the corresponding airborne laser scanning data and the DSMs generated from the Semi-Global matching (SGM) method. The experimental results show that the proposed approach is able to produce dense and reliable matches comparable to SGM in flat areas, while for densely built-up areas, the proposed method performs better than SGM. The proposed method offers an alternative solution for 3D surface reconstruction in urban areas.
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Kröhnert, M., R. Anderson, J. Bumberger, P. Dietrich, W. S. Harpole, and H. G. Maas. "WATCHING GRASS GROW- A PILOT STUDY ON THE SUITABILITY OF PHOTOGRAMMETRIC TECHNIQUES FOR QUANTIFYING CHANGE IN ABOVEGROUND BIOMASS IN GRASSLAND EXPERIMENTS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2 (May 30, 2018): 539–42. http://dx.doi.org/10.5194/isprs-archives-xlii-2-539-2018.
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Grassland ecology experiments in remote locations requiring quantitative analysis of the biomass in defined plots are becoming increasingly widespread, but are still limited by manual sampling methodologies. To provide a cost-effective automated solution for biomass determination, several photogrammetric techniques are examined to generate 3D point cloud representations of plots as a basis, to estimate aboveground biomass on grassland plots, which is a key ecosystem variable used in many experiments. Methods investigated include Structure from Motion (SfM) techniques for camera pose estimation with posterior dense matching as well as the usage of a Time of Flight (TOF) 3D camera, a laser light sheet triangulation system and a coded light projection system. In this context, plants of small scales (herbage) and medium scales are observed. In the first pilot study presented here, the best results are obtained by applying dense matching after SfM, ideal for integration into distributed experiment networks.
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Ozerbıl, Tuncer, Ergun Gokten, Mustafa Onder, Osman Selcuk, Nilhan Ciftci Sarılar, Ayhan Tekgul, Erdal Yılmaz, and Alpaslan Tutuneken. "Oblique Aerial Image Acquisition, 3D City Modeling, 3D City Guide Project for Konya Metropolitan Municipality." International Journal of 3-D Information Modeling 4, no. 2 (April 2015): 34–47. http://dx.doi.org/10.4018/ij3dim.2015040103.
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Usage of aerial oblique cameras and oblique images in generation of 3D city models has become popular all over the world in recent years and various solutions has been developed involving specialized methods and softwares. The first comprehensive step in this field was taken by Konya Metropolitan Municipality in Turkey in 2012 and the project undertaken by GEOGIS has been successfully completed in February 2014. It is the first time in Turkey that 3D city model of this large scale has been generated. The project involves: Aerial image acquisition of the project area with vertical and oblique cameras respectively and photogrammetric triangulation; Development of OttoPenta software, which can display oblique images in pentaview screen, make spatial queries and also can measure the horizontal, vertical distance and area; Digitization of roof and roof structures from vertical stereo images using photogrammetric interpretation techniques and generation of 3D solid building models using this data; Assigning building ID numbers to solid models to integrate with the GIS data of the Municipality that is available in Oracle Spatial database; Automatic texturing of 3D models with oblique images; Exporting of textured 3D models into Oracle Spatial Database in CityGML format, complying the OGC standards; and development of KNVCity software, to create and publish the 3D city guide on WEB and mobile devices. The goal of this paper is sharing the experience and knowledge that was gained during the 3D City modeling and 3D city guide project which was performed for the first time in Turkey.
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Alidoost, F., and H. Arefi. "AN IMAGE-BASED TECHNIQUE FOR 3D BUILDING RECONSTRUCTION USING MULTI-VIEW UAV IMAGES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-1-W5 (December 10, 2015): 43–46. http://dx.doi.org/10.5194/isprsarchives-xl-1-w5-43-2015.
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Nowadays, with the development of the urban areas, the automatic reconstruction of the buildings, as an important objects of the city complex structures, became a challenging topic in computer vision and photogrammetric researches. In this paper, the capability of multi-view Unmanned Aerial Vehicles (UAVs) images is examined to provide a 3D model of complex building façades using an efficient image-based modelling workflow. The main steps of this work include: pose estimation, point cloud generation, and 3D modelling. After improving the initial values of interior and exterior parameters at first step, an efficient image matching technique such as Semi Global Matching (SGM) is applied on UAV images and a dense point cloud is generated. Then, a mesh model of points is calculated using Delaunay 2.5D triangulation and refined to obtain an accurate model of building. Finally, a texture is assigned to mesh in order to create a realistic 3D model. The resulting model has provided enough details of building based on visual assessment.
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Hu, Jiuxiang, Anshuman Razdan, and Joseph A. Zehnder. "Geometric Calibration of Digital Cameras for 3D Cumulus Cloud Measurements." Journal of Atmospheric and Oceanic Technology 26, no. 2 (February 1, 2009): 200–214. http://dx.doi.org/10.1175/2008jtecha1079.1.
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Abstract A technique for calibrating digital cameras for stereo photogrammetry of cumulus clouds is presented. It has been applied to characterize the formation of summer thunderstorms observed during the Cumulus Photogrammetric, In Situ, and Doppler Observations (CuPIDO) project. Starting from gross measurements of locations, orientations of cameras, and landmark surveys, accurate locations and orientations of the cameras are obtained by minimizing a geometric error (GE). Once accurate camera parameters are obtained, 3D positions of cloud-feature points are computed by triangulation. The main contributions of this paper are as follows. First, it is proven that the GE has only one minimum in the neighborhood of the real parameters of a camera. In other words, searching the minimum of the GE enables the authors to find the right camera parameters even if there are significant differences between the initial measurements and their true values. Second, a new coarse-to-fine iterative algorithm is developed that minimizes the GE and finds the camera parameters. Numerical experiments show that the coarse-to-fine algorithm is efficient and effective. Third, a new landmark survey based on a geographic information system (GIS) rather than field measurements is presented. The GIS landmark survey is an effective and efficient way to obtain landmark world coordinates for camera calibrations in these experiments. Validation of this technique is achieved by the data collected by a NASA/Earth Observing System satellite and an instrumented aircraft. This paper builds on previous research and details the calibration and 3D reconstructions.
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Brecher, H. H. "Surface Velocity Determination on Large Polar Glaciers by Aerial Photogrammetry." Annals of Glaciology 8 (1986): 22–26. http://dx.doi.org/10.1017/s0260305500001063.
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Aerial photogrammetric block triangulation, a standard and well-developed technique for extending accurate control for mapping into the interior of a region from a few points of known position on its perimeter, can be readily adapted to determine surface velocities on bodies of ice which are too large, and often too crevassed, to be studied effectively by conventional ground surveying. Velocities are calculated from the changes in positions of the same natural surface features determined from photography of two (or more) epochs and the elapsed time. This method is capable of providing many uniformly-spaced measurements over the whole, moving, ice surface, thus allowing the production of maps of velocity and strain-rate, which are valuable in analyzing the ice-flow regime. Results from measurements completed some years ago on Byrd Glacier, one of the largest outlet glaciers from the East Antarctic plateau, are presented as an example of what the method can yield. By means of Doppler satellite surveying, relative positions of control points for each photography epoch can be determined with sub-meter accuracy, making the technique suitable also in regions where no fixed land features exist. A brief description of a project under way in such an area, on Ice Stream B in West Antarctica, is given.
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Brecher, H. H. "Surface Velocity Determination on Large Polar Glaciers by Aerial Photogrammetry." Annals of Glaciology 8 (1986): 22–26. http://dx.doi.org/10.3189/s0260305500001063.
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Aerial photogrammetric block triangulation, a standard and well-developed technique for extending accurate control for mapping into the interior of a region from a few points of known position on its perimeter, can be readily adapted to determine surface velocities on bodies of ice which are too large, and often too crevassed, to be studied effectively by conventional ground surveying. Velocities are calculated from the changes in positions of the same natural surface features determined from photography of two (or more) epochs and the elapsed time. This method is capable of providing many uniformly-spaced measurements over the whole, moving, ice surface, thus allowing the production of maps of velocity and strain-rate, which are valuable in analyzing the ice-flow regime. Results from measurements completed some years ago on Byrd Glacier, one of the largest outlet glaciers from the East Antarctic plateau, are presented as an example of what the method can yield. By means of Doppler satellite surveying, relative positions of control points for each photography epoch can be determined with sub-meter accuracy, making the technique suitable also in regions where no fixed land features exist. A brief description of a project under way in such an area, on Ice Stream B in West Antarctica, is given.
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Newby, Paul. "Practical Experiences with Automatic Aerial Triangulation: Editorial Response Based on Comments by G. Buyuksalih and the International Editorial Board of The Photogrammetric Record." Photogrammetric Record 19, no. 105 (March 2004): 80–81. http://dx.doi.org/10.1111/j.0031-868x.2004.00262_2.x.
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CHIO, SHIH-HONG. "VBS RTK GPS-ASSISTED SELF-CALIBRATION BUNDLE ADJUSTMENT FOR AERIAL TRIANGULATION OF FIXED-WING UAS IMAGES FOR UPDATING TOPOGRAPHIC MAPS." Boletim de Ciências Geodésicas 22, no. 4 (December 2016): 665–84. http://dx.doi.org/10.1590/s1982-21702016000400038.
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Unmanned Aircraft Systems (UASs) can collect high resolution and high quality images for local mapping. If the highly accurate GPS flying trajectory of a UAS is collected, it can support bundle adjustment aerial triangulation (AT) of UAS images and reduce the demands on ground control points (GCPs). This study installs a Trimble BD970 GNSS OEM on a fixed-wing UAS for capturing highly accurate GPS data by using a Virtual Base Station (VBS) RTK GPS technique for AT. Meanwhile, the GPS antenna-camera offset is resolved by stripwise linear drift parameters introduced in GPS observation equations, while performing bundle adjustment for AT. Additionally, self-calibration bundle adjustment is used in VBS RTK GPS-assisted AT to solve incomplete camera parameters calibrated by a close-range photogrammetric approach. The results show that the AT accuracy of fixed-wing UAS images collected with a 24 mm focal-length Canon EOS 5D Mark II camera at a flying height of 550 m above ground level is 0.21 m in planimetry and 0.22 m in height using two cross strips with two full GCPs at each corner of the block. The RMSE of check points from stereoscopic viewing can reach 0.27 m in planimetry and 0.24 m in height. The test results show that the accuracy of VBS RTK GPS-assisted bundle adjustment with self-calibration for the AT of fixed-wing UAS image can be used for updating local 1/5000 topographic maps in Taiwan.
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Rau, J. Y., J. P. Jhan, and R. Andaru. "LANDSLIDE DEFORMATION MONITORING BY THREE-CAMERA IMAGING SYSTEM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W13 (June 4, 2019): 559–65. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w13-559-2019.
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<p><strong>Abstract.</strong> Landslide deformation is a critical issue for WuWanZai as it will affect the road safety and cause transportation problem. Since the relief of this area is about 400 meters with an area of tens of hectares, we use an unmanned helicopter equipped with a three-camera imaging system to acquire high spatial resolution images in order to measure detail terrain variation. The unmanned helicopter can fly according to terrain slope to obtain 1&ndash;3&thinsp;cm spatial resolution images. The acquired three-camera images are stitched into one perspective image in advance to construct a large format virtual image with a frame size of 34&thinsp;mm by 78&thinsp;mm and a FOV of 53°&thinsp;&times;&thinsp;97°. Integrating ground control points that were measure by static GNSS continuous observation, we conduct aerial triangulation and dense point cloud generation by PhotoscanPro. We have acquired six dataset of UAV images since April 20, 2018. Then, we have conducted cloud-to-cloud distance calculation, DSM elevation difference calculation, ortho-image change analysis, photogrammetric points and GNSS stations displacement analysis, etc. In the end, from photogrammetric point displacement analysis, we have detected 1.6 meters displacement around the fourth curve of WuWanZai due to a heavy rainfall occurred at June 20. Based on the cloud-to-cloud distance analysis and DSM elevation difference results, we have observed more than 5 meters of height difference at the landslide area due to another heavy rainfall happened at Oct. 23&ndash;24. Experimental results demonstrate that by using the proposed UAV and three-camera imaging system can effectively detect landslide deformation in high accuracy.</p>
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Robson, S., L. MacDonald, and B. Sargeant. "METROLOGY ENABLED REFLECTION TRANSFORMATION IMAGING TO RECONSTRUCT LOCAL DETAIL IN MANUFACTURED SURFACES." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 797–804. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-797-2020.
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Abstract. Understanding the performance of large high performance manufactured structures can require highly accurate dimensional measurement across large volumes with the often conflicting capability to record critical parts of the structure in fine detail. Examples include turbine blades, aircraft wings and off-site manufactured modular structures assembled on-site for city, energy and transport infrastructure. Established large-volume industrial metrology systems such as laser trackers and photogrammetry partially meet the need through the measurement of targets and reflectors, but are limited in capability to record high density local detail needed to capture the finest manufactured features. Whilst large-volume surface sensing is possible with laser radar, photogrammetric pattern projection and contact probing for example, the detail required at a local level typically demands local sensing which generally takes the form of a tracked sensor such as a triangulation laser scanner or hand held touch probe. Local sensing systems face challenges where surfaces have fine detail of similar magnitude to the local sensing system sampling capability and particularly for optical sensors where the light reflected back to the sensor by the surface includes specular reflections compounded by local geometry. This paper investigates how Reflection Transformation Imaging (RTI) with a dome camera and lighting system might be calibrated, characterised and tracked as an alternative technology that is more robust to material surface properties and capable of very fine surface detail capture. Laboratory results demonstrate the capability to characterise and locate the dome to sub-millimetric accuracy within a large-volume tracked space to achieve local surface sampling at the 30 μm × 30 μm level. A method utilising sparse touch probe points to seed conversion of low and high frequency normal maps into a common 3D surface is explored with local agreement with laser tracker surface probe check points to the order of 30 μm.
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Batrakova, A., Y. Dorozhko, and V. Yemets. "FEATURES OF CONSTRUCTION OF DIGITAL RELIEF MODEL ACCORDING TO THE RESULTS OF GEODESIC SURVEYING LOCATIONS." Municipal economy of cities 1, no. 161 (March 26, 2021): 104–8. http://dx.doi.org/10.33042/2522-1809-2021-1-161-104-108.
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Topographic maps in digital and electronic forms are created on the basis of available paper topographic maps or on the basis of primary materials of geodetic surveys. Geodetic surveys are performed both by ground methods, without the use of photogrammetric materials, and on the basis of materials obtained as a result of ground phototheodolite or aerial photography. The construction of a digital terrain model is a multi-stage process, which consists of a significant number of interconnected operations performed at the stage of in-house processing of the results of geodetic measurements carried out during engineering and geodetic surveys. The quality of the final result of modeling depends on the quality of each stage of construction of a digital terrain model, so it is extremely important to pay attention to all technological processes of model construction. The digital relief model is considered as an ordered set of triangular faces constructed by the Delaunay algorithm. The main condition of this type of triangulation is that in the middle of the circle described around any triangle can not be the vertex of another triangle. Construction of a digital terrain model based on the results of geodetic surveying of the area in the general case can be divided into several stages. At the beginning, an automated construction of triangulation is performed on the basis of the results of geodetic measurements, which carry information about three-dimensional coordinates of survey points. Allotments adjust the display of horizontals. Regardless of the selected surface display style, the surface model is a grid of triangles. At the next stage of construction of the digital model of a relief carry out visual control of the created model and if necessary carry out editing of elements of a surface and change of position of edges of triangulation for change of position of horizontals. The last stage of building a digital terrain model based on the results of geodetic surveying of the area is the design of modeling results, the application of individual styles of reflection for individual areas of the surface and the creation of mountain strokes and signatures of horizontals.
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Gruber, Michael, Bernhard Schachinger, Marc Muick, Christian Neuner, and Helfried Tschemmernegg. "GEOMETRIC CALIBRATION AND VALIDATION OF ULTRACAM AERIAL SENSORS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W4 (March 17, 2016): 51–53. http://dx.doi.org/10.5194/isprsarchives-xl-3-w4-51-2016.
Full textAbstract:
We present details of the calibration and validation procedure of UltraCam Aerial Camera systems. Results from the laboratory calibration and from validation flights are presented for both, the large format nadir cameras and the oblique cameras as well. Thus in this contribution we show results from the UltraCam Eagle and the UltraCam Falcon, both nadir mapping cameras, and the UltraCam Osprey, our oblique camera system. This sensor offers a mapping grade nadir component together with the four oblique camera heads. The geometric processing after the flight mission is being covered by the UltraMap software product. Thus we present details about the workflow as well. The first part consists of the initial post-processing which combines image information as well as camera parameters derived from the laboratory calibration. The second part, the traditional automated aerial triangulation (AAT) is the step from single images to blocks and enables an additional optimization process. We also present some special features of our software, which are designed to better support the operator to analyze large blocks of aerial images and to judge the quality of the photogrammetric set-up.
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Gruber, Michael, Bernhard Schachinger, Marc Muick, Christian Neuner, and Helfried Tschemmernegg. "GEOMETRIC CALIBRATION AND VALIDATION OF ULTRACAM AERIAL SENSORS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XL-3/W4 (March 17, 2016): 51–53. http://dx.doi.org/10.5194/isprs-archives-xl-3-w4-51-2016.
Full textAbstract:
We present details of the calibration and validation procedure of UltraCam Aerial Camera systems. Results from the laboratory calibration and from validation flights are presented for both, the large format nadir cameras and the oblique cameras as well. Thus in this contribution we show results from the UltraCam Eagle and the UltraCam Falcon, both nadir mapping cameras, and the UltraCam Osprey, our oblique camera system. This sensor offers a mapping grade nadir component together with the four oblique camera heads. The geometric processing after the flight mission is being covered by the UltraMap software product. Thus we present details about the workflow as well. The first part consists of the initial post-processing which combines image information as well as camera parameters derived from the laboratory calibration. The second part, the traditional automated aerial triangulation (AAT) is the step from single images to blocks and enables an additional optimization process. We also present some special features of our software, which are designed to better support the operator to analyze large blocks of aerial images and to judge the quality of the photogrammetric set-up.