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  • ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
  • The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

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  • Publication . Article . Conference object . Other literature type . 2018
    Open Access English
    Authors: 
    W. Neubauer; W. Neubauer; M. Doneus; M. Doneus; M. Doneus; I. Trinks;

    Abstract. The future demands on professional archaeological prospection will be its ability to cover large areas in a time and cost efficient manner with very high spatial resolution and accuracy. The objective of the 2010 in Vienna established Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology, in collaboration with its nine European partner organisations, is the advancement of the state-of-the-art. This goal will be achieved by focusing on the development of remote sensing, geophysical prospection and virtual reality applications. Main focus will be placed on novel integrated interpretation approaches combining cutting-edge near-surface prospection methods with advanced computer science.

  • Publication . Article . Other literature type . 2012
    Open Access
    Authors: 
    Wolfgang Thaller; Ulrich Krispel; Sven Havemann; Ivan Redi; Andrea Redi; Dieter W. Fellner;
    Publisher: Copernicus GmbH

    Abstract. In the course of a project related to green building design, we have created a group of eight parametric building models that can be manipulated interactively with respect to dimensions, number of floors, and a few other parameters. We report on the commonalities and differences between the models and the abstractions that we were able to identify.

  • Publication . Article . Other literature type . 2018
    Open Access English
    Authors: 
    Deni Suwardhi; Fabio Menna; Fabio Remondino; Klaus Hanke; Rizka Akmalia;
    Publisher: Copernicus Publications

    Abstract. The Borobudur temple (Indonesia) is one of the greatest Buddhist monuments in the world, now listed as an UNESCO World Heritage Site. The present state of the temple is the result of restorations after being exposed to natural disasters several times. Today there is still a growing rate of deterioration of the building stones whose causes need further researches. Monitoring programs, supported at institutional level, have been effectively executed to observe the problem. The paper presents the latest efforts to digitally document the Borobudur Temple and its surrounding area in 3D with photogrammetric techniques. UAV and terrestrial images were acquired to completely digitize the temple, produce DEM, orthoimages and maps at 1:100 and 1:1000 scale. The results of the project are now employed by the local government organizations to manage the heritage area and plan new policies for the conservation and preservation of the UNESCO site. In order to help data management and policy makers, a web-based information system of the heritage area was also built to visualize and easily access all the data and achieved 3D results.

  • Open Access English
    Authors: 
    H.-J. Przybilla; M. Bäumker; T. Luhmann; H. Hastedt; M. Eilers;
    Publisher: Copernicus Publications

    Abstract. Unmanned Aerial Vehicles (UAV) are enjoying increasing popularity in the photogrammetric community. The Chinese supplier DJI is the market leader with about 70% of the global consumer UAV market. The Phantom model has been available for more than 10 years and its current version "RTK" is equipped with a 2-frequency GNSS receiver, as a basis for direct georeferencing of image flights, using RTK or PPK technologies.In the context of the paper, different case studies are investigated, which allow statements on the geometric accuracy of UAV image flights as well as on the self-calibration of the camera systems.In the first example, four DJI Phantom 4 RTK systems are examined, which were flown in a cross flight pattern configuration on the area of the UAV test field "Zeche Zollern" in Dortmund, Germany. The second example analyses the results of an open moorland area where the establishment of GCPs is extremely difficult and expensive, hence direct georeferencing offers a promising way to evaluate deformations, soil movements or mass calculations. In this example a DJI Matrice 210 v2 RTK drone has been used and the results of two different software packages (Agisoft Metashape and RealityCapture) are analysed. The third example presents a reference building that has been established by the Lower Saxony administration for geoinformation in order to evaluate UAV photogrammetry for cadastral purposes. Here again a DJI Phantom 4 RTK has been tested in a variety of flight configurations and a large number of high precision ground control and check points.The case studies show that the RTK option leads to sufficient results if at least 1 GCP is introduced. Flights without any GCPs lead to a significant height error in the order of up to 30 GSD.

  • Publication . Article . Part of book or chapter of book . Other literature type . 2020
    Open Access English
    Authors: 
    Martyna A. Stelmaszczuk-Górska; Estefanía Aguilar-Moreno; Sven Casteleyn; Danny Vandenbroucke; M. Miguel-Lago; Clémence Dubois; Rob Lemmens; Glenn Vancauwenberghe; M. Olijslagers; Stefan Lang; +10 more
    Publisher: International Society for Photogrammetry and Remote Sensing (ISPRS)
    Country: Germany

    Abstract. With new Earth Observation (EO) and Geoinformation (GI) data sources increasingly becoming available, evermore new skills for data collection, processing, analysis and application are required. They are needed not only from scientists, but also from practitioners working in businesses, public and private EO*GI and related sectors. Aligning the continuously evolving skill sets demanded by the market and existing academic and vocational training programmes is not an easy task. Training programmes should be grounded in real needs of the sector and its labour market. To do this, it is necessary to identify the knowledge and skills needed, and map their interconnectivity in specific frameworks, which can later be used for the definition of new curricula or job-oriented learning paths. This paper presents a framework for the EO*GI sector, based on a Body of Knowledge (BoK), by creating a complete set of concepts with a semantic structure underneath that supports academia and industry. Creating and updating the BoK is supported by an editing tool, the Living Textbook and by experts in the EO*GI domain, who contributes to the BoK’s enrichment.

  • Open Access
    Authors: 
    Zahra Dabiri; Daniel Hölbling; Lorena Abad; Dirk Tiede;
    Publisher: Copernicus GmbH

    Abstract. On July 7, 2018, a large landslide occurred at the eastern slope of the Fagraskógarfjall Mountain in Hítardalur valley in West Iceland. The landslide dammed the river, led to the formation of a lake and, consequently, to a change in the river course. The main focus of this research is to develop a knowledge-based expert system using an object-based image analysis (OBIA) approach for identifying morphology changes caused by the Hítardalur landslide. We use synthetic aperture radar (SAR) and optical remote sensing data, in particular from Sentinel-1/2 for detection of the landslide and its effects on the river system. We extracted and classified the landslide area, the landslide-dammed lake, other lakes and the river course using intensity information from S1 and spectral information from S2 in the object-based framework. Future research will focus on further developing this approach to support mapping and monitoring of the spatio-temporal dynamics of surface morphology in an object-based framework by combining SAR and optical data. The results can reveal details on the applicability of different remote sensing data for the spatio-temporal investigation of landslides, landslide-induced river course changes and lake formation and lead to a better understanding of the impact of large landslides on river systems.

  • Publication . Article . Other literature type . 2018
    Open Access English
    Authors: 
    Torsten Ullrich; Thomas Schiffer; Christoph Schinko; Dieter W. Fellner;
    Publisher: Copernicus Publications
    Project: EC | 3D-COFORM (231809)

    Abstract. The need to analyze and visualize differences of very similar objects arises in many research areas: mesh compression, scan alignment, nominal/actual value comparison, quality management, and surface reconstruction to name a few. In computer graphics, for example, differences of surfaces are used for analyzing mesh processing algorithms such as mesh compression. They are also used to validate reconstruction and fitting results of laser scanned surfaces. As laser scanning has become very important for the acquisition and preservation of artifacts, scanned representations are used for documentation as well as analysis of ancient objects. Detailed mesh comparisons can reveal smallest changes and damages. These analysis and documentation tasks are needed not only in the context of cultural heritage but also in engineering and manufacturing. Differences of surfaces are analyzed to check the quality of productions. Our contribution to this problem is a workflow, which compares a reference / nominal surface with an actual, laser-scanned data set. The reference surface is a procedural model whose accuracy and systematics describe the semantic properties of an object; whereas the laser-scanned object is a real-world data set without any additional semantic information.

  • Open Access English
    Authors: 
    Isabella Toschi; Pablo Rodríguez-Gonzálvez; Fabio Remondino; S. Minto; S. Orlandini; A. Fuller;

    Abstract. This paper discusses a methodology to evaluate the precision and the accuracy of a commercial Mobile Mapping System (MMS) with advanced statistical methods. So far, the metric potentialities of this emerging mapping technology have been studied in few papers, where generally the assumption that errors follow a normal distribution is made. In fact, this hypothesis should be carefully verified in advance, in order to test how well the Gaussian classic statistics can adapt to datasets that are usually affected by asymmetrical gross errors. The workflow adopted in this study relies on a Gaussian assessment, followed by an outlier filtering process. Finally, non-parametric statistical models are applied, in order to achieve a robust estimation of the error dispersion. Among the different MMSs available on the market, the latest solution provided by RIEGL is here tested, i.e. the VMX-450 Mobile Laser Scanning System. The test-area is the historic city centre of Trento (Italy), selected in order to assess the system performance in dealing with a challenging and historic urban scenario. Reference measures are derived from photogrammetric and Terrestrial Laser Scanning (TLS) surveys. All datasets show a large lack of symmetry that leads to the conclusion that the standard normal parameters are not adequate to assess this type of data. The use of non-normal statistics gives thus a more appropriate description of the data and yields results that meet the quoted a-priori errors.

  • Open Access English
    Authors: 
    Albert Kavelar; Sebastian Zambanini; Martin Kampel; Klaus Vondrovec; Kathrin Siegl;
    Project: FWF | Image based Classificatio... (TRP 140)

    Abstract. This paper presents the ILAC project, which aims at the development of an automated image-based classification system for ancient Roman Republican coins. The benefits of such a system are manifold: operating at the suture between computer vision and numismatics, ILAC can reduce the day-to-day workload of numismatists by assisting them in classification tasks and providing a preselection of suitable coin classes. This is especially helpful for large coin hoard findings comprising several thousands of coins. Furthermore, this system could be implemented in an online platform for hobby numismatists, allowing them to access background information about their coin collection by simply uploading a photo of obverse and reverse for the coin of interest. ILAC explores different computer vision techniques and their combinations for the use of image-based coin recognition. Some of these methods, such as image matching, use the entire coin image in the classification process, while symbol or legend recognition exploit certain characteristics of the coin imagery. An overview of the methods explored so far and the respective experiments is given as well as an outlook on the next steps of the project.

  • Publication . Article . Other literature type . 2016
    Open Access
    Authors: 
    Thomas Blaschke; Stefan Lang; Dirk Tiede; Manos Papadakis; A. Györi;
    Publisher: Copernicus GmbH

    We introduce a prototypical methodological framework for a place-based GIS-RS system for the spatial delineation of place while incorporating spatial analysis and mapping techniques using methods from different fields such as environmental psychology, geography, and computer science. The methodological lynchpin for this to happen - when aiming to delineate <i>place</i> in terms of objects - is object-based image analysis (OBIA).

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