This paper proposes a new framework for ground extraction and building detection in LiDAR data. The proposed approach constructs the connectivity of a grid over the LiDAR point-cloud in order to perform multi-scale data decomposition. This is realised by forming a top-hat scale-space using differential morphological profiles (DMPs) on pointsʼ residuals from the approximated surface. The geometric attributes of the contained features are estimated by mapping characteristic values from DMPs. Ground definition is achieved by using featuresʼ geometry, whilst their surface and regional attributes are additionally considered for building detection. A new algorithmfor local fitting surfaces (LoFS) is proposed for extracting planar points. Finally, transitions between planar ground and non-ground regions are observed in order to separate regions of similar geometrical and surface properties but different contexts (i.e. bridges and buildings). The methods were evaluated using ISPRS benchmark datasets and show superior results in comparison to the current state-of-the-art.
COBISS.SI-ID: 17466134
This paper proposes a new mapping schema, named Theta mapping, for filtering non-ground objects from LiDAR data, and the generation of a digital terrain model. By extending the CSL model, mapping extracts the most contrasted connected-components from top-hat scale-space and attributes them for an adaptive multicriterion filter definition. Areas of the most contrasted connected-components and the standard deviations of contained pointsʼ levels are considered for this purpose. Computational efficiency is achieved by arranging the input LiDAR data into a grid, represented by a Max-Tree. Since a constant number of passes over the grid is required, the time complexity of the proposed method is linear according to the number of grid-cells. As confirmed by the experiments, the average CPU execution time decreases by nearly 98%, while the average accuracy improves by up to 10% in comparison with the related method.
COBISS.SI-ID: 16937494
For the territory of Slovenia a longstanding series of aerial photographs made by cyclical aerial photogrammetric measurements of Slovenia (CAS) exist. Their use was in Slovenian geography, among others connected with land use changes and studying the degradation of the environment. There were also some attempts to use them for studying physical-geographical changes in the landscape, for example to identify changes in glacier extents or for studying the shifting of riverbeds. In this paper we present their applicability to monitor slope processes. With their help we measured the size of two rockfalls: the Čedca waterfall rockfall in the Kamnik Alps and a smaller rockfall on the slopes of Mount Glava beneath Mount Triglav. In addition, we observed changes in the relief on talus slope ‘Birški plaz' beneath Mount Veliki vrh in the Karavanke Mountains and in the torrential valley of stream Suhelj in the Sava Dolinka Valley.
COBISS.SI-ID: 37923885