2021 |
Dolapsaki, Maria Melina; Georgopoulos, Andreas Edge Detection in 3D Point Clouds Using Digital Images Journal Article In: ISPRS Int. J. Geo-Information, vol. 10, no. 4, pp. 229, 2021. Abstract | Links | BibTeX | Tags: Cultural heritage, Edge detection, large scales, Point clouds @article{Dolapsaki2021, This paper presents an effective and semi-automated method for detecting 3D edges in 3D point clouds with the help of high-resolution digital images. The effort aims to contribute towards addressing the unsolved problem of automated production of vector drawings from 3D point clouds of cultural heritage objects. Edges are the simplest primitives to detect in an unorganized point cloud and an algorithm was developed to perform this task. The provided edges are defined and measured on 2D digital images of known orientation, and the algorithm determines the plane defined by the edge on the image and its perspective center. This is accomplished by applying suitable transformations to the image coordinates of the edge points based on the Analytical Geometry relationships and properties of planes in 3D space. This plane inevitably contains the 3D points of the edge in the point cloud. The algorithm then detects and isolates those points which define the edge in the world system. Finally, the goal is to reliably locate the points that describe the desired edge in their true position in the geodetic space, using several constraints. The algorithm is firstly investigated theoretically for its efficiency using simulation data and then assessed under real conditions and under different image orientations and lengths of the edge on the image. The results are presented and evaluated. |
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 |
Edge Detection in 3D Point Clouds Using Digital Images Journal Article In: ISPRS Int. J. Geo-Information, vol. 10, no. 4, pp. 229, 2021. |
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. |