2021 |
Stathopoulou, Elisavet Konstantina; Battisti, Roberto; Cernea, Dan; Remondino, Fabio; Georgopoulos, Andreas Semantically Derived Geometric Constraints for MVS Reconstruction of Textureless Areas Journal Article In: Remote Sensing, vol. 13, no. 6, 2021, ISSN: 2072-4292. Abstract | Links | BibTeX | Tags: 3D reconstruction, dense point cloud, depth estimation, multi view stereo (MVS), PatchMatch, Plane detection, RANSAC, semantic segmentation @article{rs13061053, Conventional multi-view stereo (MVS) approaches based on photo-consistency measures are generally robust, yet often fail in calculating valid depth pixel estimates in low textured areas of the scene. In this study, a novel approach is proposed to tackle this challenge by leveraging semantic priors into a PatchMatch-based MVS in order to increase confidence and support depth and normal map estimation. Semantic class labels on image pixels are used to impose class-specific geometric constraints during multiview stereo, optimising the depth estimation on weakly supported, textureless areas, commonly present in urban scenarios of building facades, indoor scenes, or aerial datasets. Detecting dominant shapes, e.g., planes, with RANSAC, an adjusted cost function is introduced that combines and weighs both photometric and semantic scores propagating, thus, more accurate depth estimates. Being adaptive, it fills in apparent information gaps and smoothing local roughness in problematic regions while at the same time preserves important details. Experiments on benchmark and custom datasets demonstrate the effectiveness of the presented approach. |
2019 |
Mitropoulou, A; Georgopoulos, A An automated process to detect edges in unorganized point clouds Proceedings Article In: ISPRS Ann. Photogramm. Remote Sens. Spat. Inf. Sci., pp. 99–105, Copernicus GmbH, 2019, ISSN: 21949050. Abstract | Links | BibTeX | Tags: Edge detection, Plane detection, Point clouds, RANSAC @inproceedings{Mitropoulo2019, This paper presents an automated and effective method for detecting planes and their intersections as edges in unorganized pointclouds. The edges are subsequently extracted as vectors to a CAD environment. The software was developed within the MicrosoftVisual Studio and the open source Point Cloud Library (PCL, http://pointclouds.org/) was used. The Point Cloud Library is astandalone, large scale, open project for 2D/3D image and point cloud processing. The code was written in C++. For the detection ofthe planes in the point cloud the RANSAC algorithm was employed. Subsequently, and according to the standard theory of AnalyticGeometry the edges were determined as the intersections of these planes with each other. A straight line in 3D space is defined byone of its points, which was determined with the Lagrangian Multipliers method and a parallel vector, which was determined with thehelp of the cross product of two vectors on space. Finally, the algorithm and the results of the implementation of the process with realdata were evaluated by performing various checks, mainly aiming to determine the accuracy of the edge detection. |
2021 |
Semantically Derived Geometric Constraints for MVS Reconstruction of Textureless Areas Journal Article In: Remote Sensing, vol. 13, no. 6, 2021, ISSN: 2072-4292. |
2019 |
An automated process to detect edges in unorganized point clouds Proceedings Article In: ISPRS Ann. Photogramm. Remote Sens. Spat. Inf. Sci., pp. 99–105, Copernicus GmbH, 2019, ISSN: 21949050. |