TY  - JOUR
A1  - Richter, Rico
A1  - Kyprianidis, Jan Eric
A1  - Döllner, Jürgen Roland Friedrich
T1  - Out-of-core GPU-based change detection in massive 3D point clouds
JF  - Transactions in GIS
N2  - If sites, cities, and landscapes are captured at different points in time using technology such as LiDAR, large collections of 3D point clouds result. Their efficient storage, processing, analysis, and presentation constitute a challenging task because of limited computation, memory, and time resources. In this work, we present an approach to detect changes in massive 3D point clouds based on an out-of-core spatial data structure that is designed to store data acquired at different points in time and to efficiently attribute 3D points with distance information. Based on this data structure, we present and evaluate different processing schemes optimized for performing the calculation on the CPU and GPU. In addition, we present a point-based rendering technique adapted for attributed 3D point clouds, to enable effective out-of-core real-time visualization of the computation results. Our approach enables conclusions to be drawn about temporal changes in large highly accurate 3D geodata sets of a captured area at reasonable preprocessing and rendering times. We evaluate our approach with two data sets from different points in time for the urban area of a city, describe its characteristics, and report on applications.
Y1  - 2013
U6  - https://doi.org/10.1111/j.1467-9671.2012.01362.x
SN  - 1361-1682
VL  - 17
IS  - 5
SP  - 724
EP  - 741
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Delikostidis, Ioannis
A1  - Engel, Juri
A1  - Retsios, Bas
A1  - van Elzakker, Corne P. J. M.
A1  - Kraak, Menno-Jan
A1  - Döllner, Jürgen Roland Friedrich
T1  - Increasing the usability of pedestrian navigation interfaces by means of landmark visibility analysis
JF  - The journal of navigation
N2  - Communicating location-specific information to pedestrians is a challenging task which can be aided by user-friendly digital technologies. In this paper, landmark visibility analysis, as a means for developing more usable pedestrian navigation systems, is discussed. Using an algorithmic framework for image-based 3D analysis, this method integrates a 3D city model with identified landmarks and produces raster visibility layers for each one. This output enables an Android phone prototype application to indicate the visibility of landmarks from the user's actual position. Tested in the field, the method achieves sufficient accuracy for the context of use and improves navigation efficiency and effectiveness.
KW  - Pedestrian navigation
KW  - Landmark visibility
KW  - User-centred design
KW  - Usability testing
Y1  - 2013
U6  - https://doi.org/10.1017/S0373463313000209
SN  - 0373-4633
VL  - 66
IS  - 4
SP  - 523
EP  - 537
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - GEN
A1  - Delikostidis, Ioannis
A1  - Engel, Juri
A1  - Retsios, Bas
A1  - Elzakker, Corné P.J.M. van
A1  - Kraak, Menno-Jan
A1  - Döllner, Jürgen Roland Friedrich
T1  - Increasing the usability of pedestrian navigation interfaces by means of landmark visibility analysis
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - Communicating location-specific information to pedestrians is a challenging task which can be aided by user-friendly digital technologies. In this paper, landmark visibility analysis, as a means for developing more usable pedestrian navigation systems, is discussed. Using an algorithmic framework for image-based 3D analysis, this method integrates a 3D city model with identified landmarks and produces raster visibility layers for each one. This output enables an Android phone prototype application to indicate the visibility of landmarks from the user's actual position. Tested in the field, the method achieves sufficient accuracy for the context of use and improves navigation efficiency and effectiveness.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 599 
KW  - pedestrian navigation
KW  - landmark visibility
KW  - user-centred design
KW  - usability testing
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415500
SN  - 1866-8372
IS  - 599
SP  - 523
EP  - 537
ER  -