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Articles 1 - 12 of 12

Full-Text Articles in Engineering

Using T-Distributed Stochastic Neighbor Embedding For Visualization And Segmentation Of 3d Point Clouds Of Plants, Heli̇n Dutağaci Sep 2023

Using T-Distributed Stochastic Neighbor Embedding For Visualization And Segmentation Of 3d Point Clouds Of Plants, Heli̇n Dutağaci

Turkish Journal of Electrical Engineering and Computer Sciences

In this work, the use of t-SNE is proposed to embed 3D point clouds of plants into 2D space for plant characterization. It is demonstrated that t-SNE operates as a practical tool to flatten and visualize a complete 3D plant model in 2D space. The perplexity parameter of t-SNE allows 2D rendering of plant structures at various organizational levels. Aside from the promise of serving as a visualization tool for plant scientists, t-SNE also provides a gateway for processing 3D point clouds of plants using their embedded counterparts in 2D. In this paper, simple methods were proposed to perform semantic …


Geometric Quality Assessment Of A Modular House Using Bim And Photogrammetric Point Clouds, Preetam Kapsikar May 2021

Geometric Quality Assessment Of A Modular House Using Bim And Photogrammetric Point Clouds, Preetam Kapsikar

UNLV Theses, Dissertations, Professional Papers, and Capstones

As-built documentation of modular structures is an important set of records for a project, that consist of construction drawings and specifications, project design modifications, prefabrication, and component assembly. In particular, manual geometric quality assessments of a structure’s prefabricated components are generally fraught with errors, making it extremely difficult to compare the as-built construction with the specified drawings, which affects the project. Furthermore, if the prefabricated components are manufactured with errors, this can result in construction schedule delays and high additional costs due to rework. Several technologies, such as point cloud data generated using laser sensors and LiDAR, have been developed …


Improvement Of Low Traffic Volume Gravel Roads In Nebraska, Richard L. Wood, Yong-Rak Kim, Yijun Liao, Mohammad E. Mohammadi Mar 2020

Improvement Of Low Traffic Volume Gravel Roads In Nebraska, Richard L. Wood, Yong-Rak Kim, Yijun Liao, Mohammad E. Mohammadi

Nebraska Department of Transportation: Research Reports

In the state of Nebraska, over one-third of roadways are unpaved, and consequently require a significant amount of financial and operational resources to maintain their operation. Undesired behavior of surface gravel aggregates and the road surfaces can include rutting, corrugation, and ponding that may lead to reduced driving safety, speed or network efficiency, and fuel economy. This study evaluates the parameters that characterize the performance and condition of gravel roads overtime period related to various aggregate mix designs. The parameters, including width, slope, and crown profiles, are examples of performance criteria. As remote sensing technologies have advanced in the recent …


Monocular Depth Image Mark-Less Pose Estimation Based On Feature Regression, Chen Ying, Shen Li Feb 2020

Monocular Depth Image Mark-Less Pose Estimation Based On Feature Regression, Chen Ying, Shen Li

Journal of System Simulation

Abstract: Monocular camera mark-less pose estimation system suffers low accuracy, robustness and efficiency due to variety of action, self-occlusion of human body. A method of feature exaction from point clouds was proposed, in which a single-to-multiple (S2M) feature regressor and a joint position regressor were designed to quickly and accurately predict the 3D positions of body joints from a single depth image without any temporal information. Experiment result shows that the estimation accuracy is superior to that of state-of-the-arts and multi-camera based methods.


Lidar Assessment To Monitor Bridge Response Under Live And Dead Loads, Daniel Watson Dec 2019

Lidar Assessment To Monitor Bridge Response Under Live And Dead Loads, Daniel Watson

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Understanding how a bridge structure responds to various loads in a time and resource-efficient approach is vital in characterizing bridge health. Bridge health monitoring is an evaluation of the structural condition and performance, which optimizes limited transportation budgets by prioritizing the bridges that are in the most need for retrofit or replacement. Identifying and remedying issues will mitigate long-term problems and ensure that the bridge remains open to service for all legal loads. In contrast, health monitoring and load rating will determine if a bridge can only carry traffic up to a certain weight or speed, requiring a bridge load …


Robust Railroad Cable Detection In Rural Areas From Mls Point Clouds, Máté Cserép, Péter Hudoba, Zoltán Vincellér Jul 2018

Robust Railroad Cable Detection In Rural Areas From Mls Point Clouds, Máté Cserép, Péter Hudoba, Zoltán Vincellér

Free and Open Source Software for Geospatial (FOSS4G) Conference Proceedings

Monitoring of the railroad infrastructure is crucial for safety concerns and accident prevention. This task requires regular surveillance which is nowadays still carried out by expensive and time consuming manual visual inspections in many countries. The problem of railroad cable recognition (contact cables, catenary cables, return current cables) in rural areas based on LiDAR point clouds has it own methods, but current state of the art solutions suffer from extremely high computational load due the extensive size of the datasets. In this study we analyzed and compared novel robust solutions focusing on minimizing the assumptions (positions and distances of track …


Behavior Of Cold-Formed Steel Metal Industrial Buildings, Adrianna M. Early, Mohammad Ebrahim Mohammadi, Richard L. Wood, Kara D. Peterma Jan 2018

Behavior Of Cold-Formed Steel Metal Industrial Buildings, Adrianna M. Early, Mohammad Ebrahim Mohammadi, Richard L. Wood, Kara D. Peterma

Department of Civil and Environmental Engineering: Faculty Publications

This paper presents research focused on understanding the observed behavior of cold-formed steel (CFS) metal buildings during Hurricane Harvey, which made landfall Friday, August 25, 2017 between Port Aransas and Port O’Connor, Texas. Through the Geotechnical Extreme Event Reconnaissance (GEER) association (funded by the National Science Foundation) a team of structural engineers and researchers performed rapid and detailed assessments of structural damage caused by the hurricane. The National Science Foundation gathered photographs, damage assessments sheets, and three-dimensional laser point cloud data of severely damaged cold-formed steel industrial buildings. The Port Aransas County Airport experienced severe damage to several cold-formed steel …


Post-Earthquake Structural Damage Assessment Through Point Cloud Data, Mohammad Ebrahim Mohammadi, Richard L. Wood Jan 2018

Post-Earthquake Structural Damage Assessment Through Point Cloud Data, Mohammad Ebrahim Mohammadi, Richard L. Wood

Department of Civil and Environmental Engineering: Faculty Publications

Structural damage assessment following an extreme event can provide valuable information and insight into unanticipated damage and failure modes to improve design philosophies and design codes as well as reduce vulnerability. Oftentimes, structural engineers create finite element models (FEM) of the structure in which numerous model parameters require calibration to simulate the current state. This information may include structural plan details (geometry), material characteristics (strength and stiffness parameters), as well as observed damage patterns (cracks, spalling, etc.). Ground-based lidar (GBL) scans and Structure-from-Motion (SfM) can rapidly capture dimensionally accurate point clouds of the structure or facility of interest. Furthermore, point …


Damage Assessment Of Built-Up Areas Via Uas-Sfm Derived Point Cloud Data, Mohammad Ebrahim Mohammadi, Richard L. Wood Jan 2018

Damage Assessment Of Built-Up Areas Via Uas-Sfm Derived Point Cloud Data, Mohammad Ebrahim Mohammadi, Richard L. Wood

Department of Civil and Environmental Engineering: Faculty Publications

In the aftermath of extreme events (e.g., earthquakes, tsunami, tornados, etc.), rapid and reliable identification of the damage in a built-up area are crucial in to rescue, recovery, and reconstruction operations. While it is critical to conduct efficient emergency response management, lack of classified or tagged damaged regions due to communications and accessibility limitations can further delay recovery operations, rescue efforts, and resource management. Furthermore, critical and perishable damage scenes can also be lost during recovery and cleanup operations immediately following the event. In recent decades, advances in remote sensing technologies demonstrate a great potential to perform rapid reconnaissance and …


Toward Automated Aerial Refueling: Relative Navigation With Structure From Motion, Kevin W. Colson Mar 2016

Toward Automated Aerial Refueling: Relative Navigation With Structure From Motion, Kevin W. Colson

Theses and Dissertations

The USAF's use of UAS has expanded from reconnaissance to hunter/killer missions. As the UAS mission further expands into aerial combat, better performance and larger payloads will have a negative correlation with range and loiter times. Additionally, the Air Force Future Operating Concept calls for \formations of uninhabited refueling aircraft...[that] enable refueling operations partway inside threat areas." However, a lack of accurate relative positioning information prevents the ability to safely maintain close formation flight and contact between a tanker and a UAS. The inclusion of cutting edge vision systems on present refueling platforms may provide the information necessary to support …


Kinematic Modeling Of An Automated Laser Line Scanning System, Kiran Sunil Deshmukh Jan 2016

Kinematic Modeling Of An Automated Laser Line Scanning System, Kiran Sunil Deshmukh

Wayne State University Theses

This research work describes the geometric coordinate transformation in an automated laser line scanning system caused by movements required for scanning a component surface. The elements of an automated laser scanning system (robot, laser line scanner, and the component coordinate system) function as a mechanical linkage to obtain a trajectory on a component surface. This methodology solves the forward kinematics, derives the component surface, and uses inverse kinematic equations to characterize the movement of the entire automated scanning system on point trajectory. To reach a point on the component, joint angles of robot have been calculated. As a result, trajectory …


Lidar Scanning With Supplementary Uav Captured Images For Structural Inspections, Richard L. Wood, Mohammad Ebrahim Mohammadi Jan 2015

Lidar Scanning With Supplementary Uav Captured Images For Structural Inspections, Richard L. Wood, Mohammad Ebrahim Mohammadi

Department of Civil and Environmental Engineering: Faculty Publications

Structural assessment using remote sensing technologies can be performed efficiently and effectively using such technologies as LiDAR (light detection and ranging). LiDAR can be employed for various structural assessments, such as as-built conditions for a newly constructed facility, routine inspection during its service life, or structural collapse evaluation after a natural hazard or extreme event. However, the main disadvantage of LiDAR is that it is a line-of-sight technology that can result in significant occlusions. Architectural or structural components can be partially or fully occluded by another object with respect to the location of the laser scanner. Supplemental photogrammetry techniques, such …