Browsing by Author "Akça, Mehmet Devrim"
Now showing items 1-20 of 20
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3-Dimensional pre- and post-fire comparison of forest areas
Akça, Mehmet Devrim; Stylianidis, Efstratios; Poli, Daniela; Gruen, Armin W.; Altan, Mehmet Orhan; Hofer, Martin; Smagas, Konstantinos; Martin, Victor Sanchez; Garcia, Alejandro; Jimeno, Elisa; Walli, Andreas (International Society for Photogrammetry and Remote Sensing, 2018-03-06)Forest agencies give special attention to forest fires where post-disaster loss can rarely be gauged in a quick and economic way unless an appropriate technology is adopted. Determination of the planimetric and volumetric ... -
3D modeling of cultural heritage objects with a structured light system
Akça, Mehmet Devrim (Univ Agean, 2012)3D modeling of cultural heritage objects is an expanding application area. The selection of the right technology is very important and strictly related to the project requirements, budget and user's experience. The ... -
Co-registration of 3d point clouds by using an errors-in-variables model
Akça, Mehmet Devrim; Aydar, Umut; Altan, Mehmet Orhan; Akyılmaz, Orhan (Copernicus Gesellschaft MBH, 2012-08-25)Co-registration of point clouds of partially scanned objects is the first step of the 3D modeling workflow. The aim of co-registration is to merge the overlapping point clouds by estimating the spatial transformation ... -
Co-registration of surfaces by 3D least squares matching
Akça, Mehmet Devrim (Amer Soc Photogrammetry, 2010-03)A method for the automatic co-registration of 3D surfaces is presented. Die method utilizes the mathematical model of Least Squares 2D image matching and extends it for solving the 3D surface matching problem The transformation ... -
Determining pull - out deformations of bonded metal anchors embedded in concrete by means of photogrammetry
Akça, Mehmet Devrim; Avşar, Edip Özgür; Altan, Mehmet Orhan; Doğan, Umut Anıl (International Society for Photogrammetry and Remote Sensing, 2012)Chemical anchorages are applied in many engineering implementations, particularly strengthening of reinforced concrete structures. During strengthening procedure; chemical anchorages should be tested, since they supply to ... -
An emprical point error model for TLS derived point clouds
Akça, Mehmet Devrim; Özendi, Mustafa; Topan, Hüseyin (International Society for Photogrammetry and Remote Sensing, 2016)The random error pattern of point clouds has significant effect on the quality of final 3D model. The magnitude and distribution of random errors should be modelled numerically. This work aims at developing such an anisotropic ... -
FORSAT: a 3D forest monitoring system for cover mapping and volumetric 3D change detection
Stylianidis, Efstratios; Akça, Mehmet Devrim; Poli, Daniela; Hofer, Martin; Gruen, Armin W.; Sánchez Martín, Víctor; Smagas, Konstantinos; Walli, Andreas; Altan, Mehmet Orhan; Jimeno, Elisa; Garcia, Alejandro (Taylor and Francis Ltd., 2020-08-02)A 3D forest monitoring system, called FORSAT (a satellite very high resolution image processing platform for forest assessment), was developed for the extraction of 3D geometric forest information from very high resolution ... -
A generic point error model for TLS derived point clouds
Özendi, Mustafa; Akça, Mehmet Devrim; Topan, Hüseyin (SPIE-Int Soc Optical Engineering, 2017-06-26)This work aims at developing a generic and anisotropic point error model, which is capable of computing magnitude and direction of a priori random errors, described in the form of error ellipsoids for each individual point ... -
Laboratory flume experiment with a coded structured light system
Akça, Mehmet Devrim; Seybold, Hansjorg (International Society for Photogrammetry and Remote Sensing, 2012)The topography of inland deltas is influenced chiefly by the water-sediment balance in distributary channels and local evaporation and seepage rates. In a previous study, a reduced complexity model has been applied to ... -
Monitoring of a laboratory-scale inland-delta formation using a structured-light system
Akça, Mehmet Devrim; Seybold, Hansjörg J. (Blackwell Publishing Ltd, 2016-06)A reduced complexity model, which simulates the process of fluvial inland-delta formation, has been developed in a previous study. The results have been compared and validated with a laboratory experiment. This work ... -
Photogrammetric deformation monitoring of the second Bosphorus Bridge in Istanbul
Avşar, Özgür; Akça, Mehmet Devrim; Altan, Mehmet Orhan (International Society for Photogrammetry and Remote Sensing, 2014)Improving the efficiency of bridge inspection and minimizing the impact of dynamic load on the long term deterioration of the bridge structure reduces maintenance and upkeep costs whilst also improving bridge longevity and ... -
Photogrammetric monitoring of an artificially generated landslide
Akça, Mehmet Devrim; Gruen, Armin W.; Askarinejad, Amin; Springman, Sarah Marcella (Copernicus GmbH, 2011-05-08)According to pre-planned schedules, a series of two artificial rainfall events were applied to a forested slope in Ruedlingen, northern Switzerland. The experiments were conducted in autumn 2008 and spring 2009, the second ... -
Photogrammetric monitoring of an artificially generated shallow landslide
Akça, Mehmet Devrim (Wiley-Blackwell, 2013-06)An artificial rainfall event was applied to a forested slope in Ruedlingen, northern Switzerland. The experiment triggered a landslide which resulted in mobilising about 130m3 of debris. The event was monitored by a ... -
Pre- and post-fire comparison of forest areas in 3D
Akça, Mehmet Devrim; Stylianidis, Efstratios; Poli, Daniela; Gruen, Armin W.; Altan, Mehmet Orhan; Hofer, Martin; Smagas, Konstantinos; Martin, Victor Sanchez; Walli, Andreas; Jimeno, Elisa; Garcia, Alejandro (Springer Berlin Heidelberg, 2019)A satellite processing platform for high resolution forest assessment (FORSAT) was developed. It generates the digital surface models (DSMs) of the forest canopy by advanced processing of the very-high resolution (VHR) ... -
A precision estimation method for volumetric changes
Akça, Mehmet Devrim; Stylianidis, Efstratios; Gruen, Armin W.; Altan, Mehmet Orhan; Hofer, Martin; Smagas, Konstantinos; Sanchez Martin, Victor; Walli, Andreas; Jimeno, Elisa; Garcia, Alejandro (IEEE, 2019-06)Earth surface changes are often computed by comparing the sequences of digital elevation models (DEMs) so called the DEM of difference (DoD) method. We present an operational DEM generation, co-registration and DoD comparison ... -
Precursors of instability in a natural slope due to rainfall: a full-scale experiment
Askarinejad, Amin; Akça, Mehmet Devrim; Springman, Sarah Marcella (Springer Heidelberg, 2018-09)A full-scale landslide-triggering experiment was conducted on a natural sandy slope subjected to an artificial rainfall event, which resulted in mobilisation of 130m(3) of soil mass. Novel slope deformation sensors (SDSs) ... -
Quality assessment of 3D building data
Akça, Mehmet Devrim; Freeman, Mark; Sargent, Isabel; Gruen, Armin W. (Wiley-Blackwell Publishing, 2010-12)Three-dimensional building models are often now produced from lidar and photogrammetric data. The quality control of these models is a relevant issue both from the scientific and practical points of view. This work presents ... -
Stochastic surface mesh reconstruction
Özendi, Mustafa; Akça, Mehmet Devrim; Topan, Hüseyin (International Society for Photogrammetry and Remote Sensing, 2018-05-30)A generic and practical methodology is presented for 3D surface mesh reconstruction from the terrestrial laser scanner (TLS) derived point clouds. It has two main steps. The first step deals with developing an anisotropic ... -
Topography of inland deltas: Observations, modeling, and experiments
Seybold, Hansjörg J.; Molnar, Peter; Akça, Mehmet Devrim; Doumi, M.; Tavares, M. Cavalcanti; Shinbrot, Troy; Andrade, Jose Soares; Kinzelbach, Wolfgang; Herrmann, Hans Jürgen (Amer Geophysical Union, 2010-04-28)The topography of inland deltas is influenced by the water-sediment balance in distributary channels and local evaporation and seepage rates. In this letter a reduced complexity model is applied to simulate inland delta ... -
Total least squares registration of 3D surfaces
Aydar, Umut; Akça, Mehmet Devrim; Altan, Mehmet Orhan; Akyılmaz, Orhan (Copernicus GmbH, 2013-10-16)Co-registration of point clouds of partially scanned objects is the first step of the 3D modeling workflow. The aim of coregistration is to merge the overlapping point clouds by estimating the spatial transformation ...
