Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 25 for “"Laser scanners"”.
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A phase-locked loop for laser scanners
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1984.
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Establishment of Accuracy Testing Facilities for Terrestrial Laser Scanners
… at the required level of accuracy. A Terrestrial Laser Scanner is one such instrument and with the vast amount of information that this machine is able to capture, it is especially important to run regular accuracy checks. This research is building on the work that has been done by previous …
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An evaluation of computer assisted skull re-assembly using hand held and automated laser scanners
… produced by radiological CT or optical surface laser scans. The accuracy of CAD reassembly and the contribution the technologies of image production make to the process are largely unevaluated. This research uses four 3D models produced by a hand held laser scanner (Scorpion FASTSCAN by …
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D4ar- 4 Dimensional Augmented Reality - Models or Automation and Interactive Visualization of Construction Progress Monitoring
… other methods that focus on application of laser scanners or time-lapse photography, this approach is able to use existing information without adding burden of explicit data collection on project management and reports competitive accuracies compared to those reported with laser scanners …
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Evaluating the performance of multi-rotor UAV-Sfm imagery in assessing simple and complex forest structures: comparison to advanced remote sensing sensors
… to more accurate LiDAR data obtained from Aerial Laser Scanners (ALS), Terrestrial Laser Scanners (TLS), and more conventional means like manual field measurements. TH was assessed using UAVSfM and LiDAR point cloud derived DTMs, while DBH was assessed by comparing UAVSfM photogrammetric point …
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Creating 3D models of cultural heritage sites with terrestrial laser scanning and 3D imaging
The advent of terrestrial laser-scanners made the digital preservation of cultural heritage sites an affordable technique to produce accurate and detailed 3D-computermodel representations for any kind of 3D-objects, such as buildings, infrastructure, and even entire landscapes. However, one of the …
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Enhancing the Resolution and Predicting the Accuracy of Point Clouds Generated by Handheld 3D Scanners in Construction
… data acquisition relying on terrestrial laser scanners or photogrammetry methods is labor-intensive during both the scanning and post-processing phases. Handheld scanners theoretically present a solution to this challenge due to their potential to significantly reduce on-site scanning …
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Error Mitigation in Roughness Measurements
… are commonly used. Modern systems based on laser scanners and inertial navigation systems (INS) are able to measure thousands of data points per seconds over a wide path. However, because of the subsystems in the profiling systems, they are susceptible to errors that reduce the accuracy of …
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Modellierung des retinalen Blutflusses durch Auswertung bewegungskorrigierter Angiographie-Bildfolgen
… einzelner Bilder. Erst die Einführung des Laser-Scanners in die Ophthalmologie ermöglichte eine schnelle und kontinuierliche Bildaufnahme. Der Anschluß dieser Systeme an leistungsfähige Rechner erlaubt die digitale Speicherung des kompletten Einströmvorgangs des Farbstoffs in das …
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Underwater simulation and mapping using imaging sonar through ray theory and Hilbert maps
… of research and has remarkable solutions using laser scanners, but most of the underwater mapping is focused on 2D maps, treating the environment as a floor plant, or on 2.5D maps of the seafloor. The reason for the problematic of underwater mapping originates in its sensor, i.e. sonars. In …
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An autonomous forklift research platform for warehouse operations
… capacity. The vehicle is equipped with cameras, laser scanners, an IMU and a powerful onboard computer. A reference software implementation is also developed and tested, which allows a base level of full autonomy, enabling the vehicle to perform autonomous pick and place tasks. In it's role as a …
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Assessing the Technology Used by UAVs in Data Acquisition on Construction Sites
… the technology of UAVs, cameras, thermographic scanners, and laser scanners with Light Detection and Ranging (LiDAR), this research will investigate how 3D Building Information Models (BIMs) can be created for real time project management decision making. UAVs with camera and laser scanning …
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The Use of Image and Point Cloud Data in Statistical Process Control
… as machine vision systems (MVSs) and 3D surface scanners, diversify the types of data being collected, further pushing data collection beyond discrete dimensional data. These large and diverse datasets increase the challenge of extracting useful information. Unfortunately, industry still relies …
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Advancing Manufacturing Quality Control Capabilities Through The Use Of In-Line High-Density Dimensional Data
… (HDD) measurement technologies, such as 3D laser scanners, data-sets consisting of an almost complete representation of a manufactured part's geometry can now be obtained. While HDD data measurement devices have traditionally been used in reverse engineering application, they are beginning …
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Optimization of photonic crystal enhanced fluorescence by excitation laser angle scanning
… as those used in commercially available confocal laser scanners, but with a reduction in the obtainable enhancement factor. Using computer simulations and experimental measurements, we describe the interaction between the resonant bandwidth of a PCEF device surface and the optical design of the …
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D4AR-4 dimensional augmented reality-models for automation and interactive visualization of construction progress monitoring
… other methods that focus on application of laser scanners or time-lapse photography, this approach is able to use existing information without adding burden of explicit data collection on project management and reports competitive accuracies compared to those reported with laser scanners …
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Where the Ice Ends: Calving and Ice-Ocean Interactions at Helheim Glacier and Beyond
… we installed two autonomous terrestrial laser scanners (ATLAS) overlooking the terminus at Helheim Glacier, East Greenland, the first in 2015 and the second in 2018. Each laser scanner system scans every 6 hours during non-winter months and once a day during winter. Together, these …
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High-quality 3D shape measurement with binarized dual phase-shifting method
… <p>Some of the well-known technologies include laser scanners, stereo vision, and structured</p> <p>light systems. The main limitation of laser scanners is its limited speed due to its point-by-point</p> <p>or line-by-line scanning process. The stereo vision uses two cameras which take …
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Shape Analysis Using Spectral Geometry
… advanced acquisition capture devices, e.g., laser scanners, depth cameras, and CT/MRI scanners. The increasing data demands advanced analysis tools including shape matching, retrieval, deformation, etc. Nevertheless, 3D Shapes are represented with Euclidean transformations such as …
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Terrestrial laser scanning to characterise three-dimensional foliage and woody material distributions in trees
… ecosystems. The recent advances in terrestrial laser scanning (TLS) technologies have provided new opportunities to measure the 3D structure of forest canopies, which in turn can be correlated to tree attributes. In addition to estimation of variables such as stem density and the diameter at …
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