Article
Environmental Sciences
Martin Stroner, Rudolf Urban, Lenka Linkova
Summary: This paper presents a newly developed multidirectional shift rasterization (MDSR) filter, which excellently identifies ground points with high accuracy while filtering out most vegetation and above-ground points, outperforming other commonly used filters.
Article
Geography, Physical
Nannan Qin, Weikai Tan, Lingfei Ma, Dedong Zhang, Haiyan Guan, Jonathan Li
Summary: The capability of ALS in collecting high-precision point clouds over large areas makes it valuable for geospatial applications. Automated ground filtering (GF) is a fundamental and challenging step, and recent advancements in deep learning (DL) techniques provide a new solution for this problem. However, there is a scarcity of public 3D geospatial datasets, especially for landform-scale GF tasks. Comprehensive advancements in DL-based GF pipelines are achieved by publishing a large-scale GF dataset and evaluating the advantages of DL techniques through experimental comparisons with traditional methods.
ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
(2023)
Article
Engineering, Electrical & Electronic
Lucas P. Ramos, Dimas I. Alves, Leonardo T. Duarte, Mats I. Pettersson, Renato Machado
Summary: Robust principal component analysis (RPCA) and tensor RPCA (TRPCA) techniques are valuable for ground scene estimation (GSE) in synthetic aperture radar (SAR) imagery, improving the performance of change detection methods.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2023)
Article
Environmental Sciences
Zhen Zheng, Bingting Zha, Yu Zhou, Jinbo Huang, Youshi Xuchen, He Zhang
Summary: This paper proposes a single-stage adaptive multi-scale noise filtering algorithm for point clouds based on feature information. The algorithm divides the point cloud into different regions using adaptive thresholds, and filters them separately to enhance computational efficiency and filtering performance.
Article
Chemistry, Analytical
Xinming Pu, Shu Gan, Xiping Yuan, Raobo Li
Summary: This study combines the advantages of different point cloud acquisition methods to provide high-quality basic data for structure measurement and modeling. By analyzing the mechanisms of different sensors, the integrity of point cloud data, and the single-point geometric characteristics, the advantages and disadvantages of different methods for collecting point clouds of special-shaped structures are compared. Additionally, a point cloud void repair technology based on TLS point cloud is proposed to generate high-quality basic point cloud data of special-shaped structures.
Review
Green & Sustainable Science & Technology
Shella M. Santos, Maria R. Wolf-Maciel, Leonardo Fregolente
Summary: Biodiesel, as a popular biofuel, has lower emissions and is renewable and biodegradable. However, its applicability at low temperatures requires caution due to crystallization. Certain esters were found to influence the cold flow properties of biodiesel, and new predictive methods were developed to determine its performance at low temperatures.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2023)
Article
Agricultural Engineering
Chenglong Zhang, Christiaan Mouton, Joao Valente, Lammert Kooistra, Rachel van Ooteghem, Dirk de Hoog, Pieter van Dalfsen, Peter Frans de Jong
Summary: This study proposes a framework for combining UAV and ground based RGB image data to detect flowering intensity in a Dutch Elstar apple orchard. Two linear regression models based on unsupervised machine learning methods were trained and validated, achieving good results. The proposed methods can guide flower thinning and provide flexible intra-tree inspection.
BIOSYSTEMS ENGINEERING
(2022)
Article
Construction & Building Technology
Manohar Yadav, Parvej Khan, Ajai Kumar Singh, Bharat Lohani
Summary: A hybrid ground filtering method was proposed for processing ground points in mobile laser scanning data. After testing and validation, the method showed good performance in various challenging roadway environments. The method is straightforward, computationally efficient, and has the potential for wider application in industry.
AUTOMATION IN CONSTRUCTION
(2021)
Article
Optics
Meiting Xin, Bing Li, Xiang Wei, Zhuo Zhao
Summary: This paper proposes a rapid 3D point cloud registration method based on weighted principal component analysis and re-weighted iterative closest point algorithm, which consists of three stages: coarse alignment, data simplification, and fine alignment, aiming to improve the efficiency of reverse engineering.
Article
Computer Science, Artificial Intelligence
Yuxiao Du, Yuxing Li, Zhuocheng Wu, Feng Chen, Zhiheng Chen, Yinglin Li
Summary: In this study, a depth camera was used for noncontact measurement of the human body. Through coordinate transformation and point cloud data preprocessing, the complete outline of the human body was obtained, and the measurement results were within the range of relevant standard accuracy.
INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS
(2022)
Article
Chemistry, Multidisciplinary
Yueqiao Wu, Mengting Sang, Wei Wang
Summary: This paper focuses on the filtering of point cloud data in forest areas, proposing a new method that combines iterative minima with machine learning to reduce manual intervention, and achieving good filtering results in three different types of woodland areas.
APPLIED SCIENCES-BASEL
(2022)
Article
Environmental Sciences
Marco Balsi, Salvatore Esposito, Paolo Fallavollita, Maria Grazia Melis, Marco Milanese
Summary: This paper presents a case study of using remote sensing with a LiDAR sensor carried by a UAV for detailed topographic survey at archaeological sites. Expert operators searched for prehistoric hypogea entrances in the high-resolution digital terrain model obtained from the ground-labeled point cloud. The study demonstrates the utility of this technique in revealing hidden anthropogenic structures and quickly documenting ground surface topography.
Article
Environmental Sciences
Anjin Chang, Jinha Jung, Junho Yeom, Juan Landivar
Summary: This study developed a method for detecting and characterizing individual sorghum panicles using a 3D point cloud derived from UAV images, and proposed strategies to estimate panicle volumes. Experimental results showed a high correlation between UAV-derived panicle parameters and ground measurements, providing important information for studying genetic diversity and yield estimation in sorghum.
Article
Engineering, Electrical & Electronic
Yue Wu, Xidao Hu, Yue Zhang, Maoguo Gong, Wenping Ma, Qiguang Miao
Summary: In this paper, a skip-attention based correspondence filtering network (SACF-Net) is proposed for point cloud registration. It utilizes a feature interaction mechanism and attention mechanism to extract high-quality correspondences from different resolutions of the encoder, leading to unprecedented performance improvements on indoor and outdoor scene datasets.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY
(2023)
Article
Geochemistry & Geophysics
Xijiang Chen, Bufan Zhao
Summary: This article presents a new method for extracting contour feature points from point clouds, which includes extracting conspicuous and inconspicuous boundary points based on the distribution characteristics of azimuth between adjacent vectors in 2D view, and constructing a 2D projection plane and extracting crease points based on the distribution mechanism of adjacent points in the 2D view. The proposed method shows superior extraction and anti-noise performance compared to other methods.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Chemistry, Analytical
Martin Stroner, Rudolf Urban, Tomas Reindl, Jan Seidl, Josef Broucek
Article
Environmental Sciences
Ludovit Kovanic, Peter Blistan, Rudolf Urban, Martin Stroner, Monika Blist'anova, Karol Bartos, Katarina Pukanska
Article
Environmental Sciences
Martin Stroner, Rudolf Urban, Jan Seidl, Tomas Reindl, Josef Broucek
Summary: This study examines systematic elevation errors in georeferencing UAV-acquired imagery without using ground control points (GCPs), and proposes strategies for eliminating this error. By conducting multiple flights at different altitudes and image acquisition axes, the research demonstrates a linear dependence between focal length deviation and systematic elevation error, and shows that a combination of two flights with different image acquisition axes can reduce the error to less than 0.03 meters. Overall, georeferencing without GCPs is a feasible alternative to traditional methods.
Article
Chemistry, Multidisciplinary
Ludovit Kovanic, Peter Blistan, Martin Stroner, Rudolf Urban, Monika Blistanova
Summary: This study analyzed the measurement and data processing results for material documentation and quantification in large areas, confirming the suitability, efficiency, and accuracy of using digital aerial photogrammetry for heap volumes and documentation. The method was compared with GNSS RTK and terrestrial laser scanning, showing minimal volume differences and high precision in digital aerial photogrammetry measurements.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Multidisciplinary
Tomas Suk, Martin Stroner
Summary: The paper presents the results of a long-term experiment on temperature measurement in engineering surveying, focusing on the theoretical effect of the atmosphere on measured zenith angles. By determining accurate temperature gradients at various heights in different seasons, a numerical model was used to calculate refraction-induced vertical shifts.
Article
Environmental Sciences
Martin Stroner, Rudolf Urban, Lenka Linkova
Summary: This paper introduces a method using high-reflectivity foil-covered accurately georeferenced targets to verify the accuracy of UAV lidar systems. By comparing the lidar point cloud with a dense SfM point cloud, the systematic shift is successfully removed, revealing that the accuracy of the system is better than the manufacturer-declared values.
Article
Environmental Sciences
Martin Stroner, Rudolf Urban, Lenka Linkova
Summary: This paper presents a newly developed multidirectional shift rasterization (MDSR) filter, which excellently identifies ground points with high accuracy while filtering out most vegetation and above-ground points, outperforming other commonly used filters.
Article
Chemistry, Multidisciplinary
Martin Stroner, Tomas Kremen, Rudolf Urban
Summary: This article presents an easy-to-use and computationally inexpensive progressive dilution method for reducing the number of points in point clouds while preserving details. The method is based on the local scattering of the cloud and demonstrates excellent performance in handling highly rugged/curved areas and flat areas.
APPLIED SCIENCES-BASEL
(2022)
Article
Remote Sensing
Martin Stroner, Rudolf Urban, Tomas Kremen, Jaroslav Braun
Summary: In this study, the accuracy and coverage of LiDAR-UAV system DJI Zenmuse L1 and Digital Aerial Photogrammetric system (DAP-UAV) DJI Zenmuse P1 were evaluated in a forested area under leaf-off conditions on three sites with varying terrain ruggedness and tree type combinations. The results showed that branches did not affect the accuracy of the LiDAR-UAV and DAP-UAV derived terrain clouds. The photogrammetric data had even better elevation accuracy than LiDAR data, reaching as low as 0.015 m on all sites. However, the LiDAR system provided better coverage, with almost full coverage at all sites, while the DAP-UAV coverage declined with increasing density of branches.
EUROPEAN JOURNAL OF REMOTE SENSING
(2023)
Article
Environmental Studies
L'udovit Kovanic, Martin Stroner, Rudolf Urban, Peter Blistan
Summary: There are numerous talus cones in the Small Cold Valley, Slovakia, formed by long-term geological processes and sudden hydrological events. Due to recent rock avalanches and landslides, the safety of frequent hiking trails in this area needs to be monitored. A complex methodology using non-contact UAS photogrammetry with SfM-MVS processing was developed to monitor changes in the talus cones and evaluate the extent, pace, nature, and origin of the morphological changes. Comparing the actual state of a talus cone in 2018 and 2022, significant morphological changes were observed using spatial models represented by point clouds with centimeter-level accuracy. Geodetic and geological knowledge was synthesized to evaluate the phenomena occurring in this territory.
Article
Engineering, Multidisciplinary
Ludovit Kovanic, Martin Stroner, Peter Blistan, Rudolf Urban, Rudolf Boczek
Summary: The geometric parameters of large-scale machinery are checked using traditional geodetic and measuring methods. For a rotary kiln (RK), the focus is on determining its real longitudinal axis geometry and shell deformation. The geodetic methods employ total station (TS) or terrestrial laser scanning (TLS) for 3D coordinate measurements. In this research, these methods were used as ground-truth references to evaluate the SfM-MVS approach in 3D modeling and rotary kiln geometry derivation.
Article
Environmental Sciences
Martin Stroner, Rudolf Urban, Tomas Suk
Summary: Filtering out vegetation from a point cloud based on color is rarely used due to the lack of knowledge regarding input information and thresholding methods. This study evaluated multiple vegetation indices and threshold determination methods, and found that the ExG and GLI indices, combined with a simple threshold determination method, provided the best accuracy for removing vegetation from rocky and anthropogenic surfaces.
Article
Geosciences, Multidisciplinary
Martin Stroner, Rudolf Urban, Tomas Suk, Vilem Kolar
Summary: Point clouds are commonly used to describe objects in engineering disciplines. This paper presents a new method of filtering point clouds using the visible spectrum color principle and RGB system colors to determine vegetation indexes. The method simplifies the operator's work through means clustering and can be implemented in the CloudCompare software.
ACTA MONTANISTICA SLOVACA
(2022)
Article
Geosciences, Multidisciplinary
Rudolf Urban, Martin Stroner, Ivan Kuric
ACTA MONTANISTICA SLOVACA
(2020)