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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Mobilní mapování / Mobile Mapping

Manda, David January 2013 (has links)
The aim of this thesis is introduce the mobile mapping system IP-S2, which is using by company GEODIS BRNO, and perform data collection by this system. Measure the identical points, determine their coordinates and compare with coordinates obtained by mobile mapping system. The conclusion of this thesis is focused on testing the accuracy of the mobile mapping system.
32

Empirische Untersuchung der Gestaltung von Positionssignaturen für mobile Endgeräte

Alexander, Nicole 05 March 2012 (has links) (PDF)
In dieser Arbeit werden verschiedene Gestaltungsmöglichkeiten von Positionssignaturen auf mobilen Geräten untersucht. Vor allem beim Gebrauch von Kartenanwendungen auf mobilen Geräten ist nicht ausreichend Platz um eine Legende mit anzubringen, wodurch alle Kartenzeichen eindeutig erklärt werden können. Hierfür müssen besonders eindeutige und selbsterklärende Zeichen verwendet werden, die in ihrer Gestaltung keine Verwirrung beim Nutzer hervorrufen. Aus diesem Grund wurden folgende Gestaltungsvariablen zur Untersuchung ausgewählt: symbolhaft versus bildhaft, zweidimensional versus dreidimensional und Signaturen mit Rahmen und Hintergrund versus Signaturen ohne Rahmen und Hintergrund. Diese sind zur Untersuchung in verschiedenen Kombinationen gesetzt, werden aber mit Hilfe eines geeigneten Auswerteverfahrens auch einzeln analysiert. Des Weiteren werden diese Gestaltungsvariablen hinsichtlich verschiedener Erkennungsprozesse untersucht. Denn man nimmt an, dass eine Gestaltungsvariable zwar eine große Aufmerksam-keit erregen kann, dennoch aber nicht gut zu interpretieren sein muss. Die erwähnten Prozesse stellen die Lokalisation, Identifikation und Interpretation dar. Diese Erforschung ist insofern wichtig, da verschiedene Gestaltungen je nach Aufgabenspezifik eingesetzt werden können, damit der Nutzer schneller zu einer Lösung findet. Die Untersuchung findet im Rahmen eines Feldtests an einem mobilen Gerät statt, für dessen Durchführung eine Test-Applikation im Android-SDK geschrieben wurde. Hierbei müssen die Probanden Signaturen, zum Teil nach vorher genannten Begriffen, schnellstmöglich entdecken/interpretieren. Ferner wird ein Interview mit den Testkandidaten durchgeführt, von dem die Ergebnisse mit den Daten der Reaktionszeitmessung verglichen werden.
33

Testování přesnosti mobilního laserového skenování / Testing of an Accuracy of Mobile Laser Scanning

Hoffmannová, Lada January 2020 (has links)
Diploma thesis describes collecting of data by mobile mapping system Riegl VMX-450. Science centre AdMas was captured with mobile mapping system. For the purpose of testing the accuracy, a calibration field was constructed in AdMaS. Main part of the thesis deals with testing of the accuracy of point cloud. Calibration field's coordinates were obtained by adjustment of the geodetic network using the least squares adjustment. During the testing, the coordinates of the calibration field points determined by the adjustment of the geodetic network and the coordinates of the points determined from the point cloud were compared. Another part of the work deals with testing of the accuracy, when target's position is in different height levels.
34

Vypracování metodik pro tvorbu informačního modelu budovy / Working out of methodology for creation of building information model

Nováková, Věra January 2014 (has links)
This thesis is focused on creation of building information model (BIM) for existing buildings. The main objective of this work is to develop the methodology (workflow) for the creation of BIM model using selected geodetic methods, specifically for the modeling based on the existing documentation of the building, the modeling from the handheld distance meter and the modeling from point cloud acquired by the indoor mapping system. The aim of these workflows is to explore the suitability of these methods, to check the limits of each method and to point out the potential issues. Revit (version 2013 and 2014) was used as an authoring environment for creation of the models. Workflow for modeling based on the documentation of the building shows how to insert drawings into Revit and how to create a model based on these drawings. The workflow was developed based on experience with creation of model of an office building. The workflow for handheld laser distance meter describes how to work with rangefinder equipped with Bluetooth, which allows user to create a model onsite. The third part of this thesis deals with creation of BIM from pointcloud acquired by indoor mobile mapping system. The workflow describes data collection and point clouds processing directly in Revit using the ScanToBIM extension. The results of this work are methodical instructions for the methods described above and the comparison of these methods. Workflows contain recommended procedures and highlight common issues and mistakes. This should enable the readers of this thesis to choose the right method and avoid common mistakes.
35

Empirische Untersuchung der Gestaltung von Positionssignaturen für mobile Endgeräte

Alexander, Nicole 22 February 2012 (has links)
In dieser Arbeit werden verschiedene Gestaltungsmöglichkeiten von Positionssignaturen auf mobilen Geräten untersucht. Vor allem beim Gebrauch von Kartenanwendungen auf mobilen Geräten ist nicht ausreichend Platz um eine Legende mit anzubringen, wodurch alle Kartenzeichen eindeutig erklärt werden können. Hierfür müssen besonders eindeutige und selbsterklärende Zeichen verwendet werden, die in ihrer Gestaltung keine Verwirrung beim Nutzer hervorrufen. Aus diesem Grund wurden folgende Gestaltungsvariablen zur Untersuchung ausgewählt: symbolhaft versus bildhaft, zweidimensional versus dreidimensional und Signaturen mit Rahmen und Hintergrund versus Signaturen ohne Rahmen und Hintergrund. Diese sind zur Untersuchung in verschiedenen Kombinationen gesetzt, werden aber mit Hilfe eines geeigneten Auswerteverfahrens auch einzeln analysiert. Des Weiteren werden diese Gestaltungsvariablen hinsichtlich verschiedener Erkennungsprozesse untersucht. Denn man nimmt an, dass eine Gestaltungsvariable zwar eine große Aufmerksam-keit erregen kann, dennoch aber nicht gut zu interpretieren sein muss. Die erwähnten Prozesse stellen die Lokalisation, Identifikation und Interpretation dar. Diese Erforschung ist insofern wichtig, da verschiedene Gestaltungen je nach Aufgabenspezifik eingesetzt werden können, damit der Nutzer schneller zu einer Lösung findet. Die Untersuchung findet im Rahmen eines Feldtests an einem mobilen Gerät statt, für dessen Durchführung eine Test-Applikation im Android-SDK geschrieben wurde. Hierbei müssen die Probanden Signaturen, zum Teil nach vorher genannten Begriffen, schnellstmöglich entdecken/interpretieren. Ferner wird ein Interview mit den Testkandidaten durchgeführt, von dem die Ergebnisse mit den Daten der Reaktionszeitmessung verglichen werden.:Selbstständigkeitserklärung I Danksagung II Zusammenfassung III Inhaltsverzeichnis 1 Abbildungsverzeichnis 3 Tabellenverzeichnis 4 1 Einleitung 5 2 Grundlagen von Positionssignaturen und artverwandten Icons 7 2.1 Funktionen von Positionssignaturen in der Kartographie 7 2.1.1 Besonderheiten in der mobilen Kartographie 7 2.1.2 Aufgaben von Positionssignaturen 10 2.1.3 Gestaltung von Positionssignaturen 11 2.2 Icons 16 2.2.1 Theoretische Grundlagen 16 2.2.2 Empirische Untersuchungen von Icons 18 3. Grundlagen visueller Aufmerksamkeit und Wahrnehmung 22 3.1 Definitionen 22 3.2 Visuelle Aufmerksamkeit und Verarbeitung 23 3.3 Wahrnehmung des visuellen Reizes 25 3.4 Frühere Untersuchungen zur Wahrnehmbarkeit von Signaturen 27 4. Konzeptvorstellung und Durchführung einer empirischen Untersuchung 29 4.1 Ziele 29 4.2 Untersuchungsaspekte 30 4.3 Testplanung 35 4.3.1 Testdesign 36 4.3.2 Testpersonen 41 4.3.3 Testgerät 43 4.4 Hypothesenbildung 44 4.5 Ausarbeitung eines Prototyps 47 4.5.1 Android - Betriebssystem 47 4.5.2 Android – Softwareplattform 48 4.5.3 Erstellung der Android-Application 54 4.6 Ausarbeitung der Interviewfragen 59 4.7 Durchführung der Tests 61 5. Auswertung der Testergebnisse 65 5.1 Grundlagen statistischer Auswerteverfahren 65 5.2 Ergebnisse des Interviews 69 5.2.1 Zusammenfassung der Antworten 69 5.2.2 Deskriptive Auswertung 71 5.3 Ergebnisse der Reaktionszeiten 77 5.3.1 Aufbereitung der Daten 77 5.3.2 Deskripte Auswertung 79 5.3.3 Interferenzstatistische Auswertung 88 5.4 Vergleich der Methoden und Ergebnisse 98 5.4.1 Vergleich der Evaluationsmethoden 98 5.4.2 Vergleich der Ergebnisse der Evaluationsmethoden 101 6. Interpretation 103 7. Fazit 109 Literaturverzeichnis 111 Anhang 115
36

Automatic image-based road crack detection methods

Some, Liene January 2016 (has links)
Pavement crack detection is an important procedure in road maintenanceand traffic safety. Traditionally, the road inventory was performed by field inspection, now it is replaced by the evaluation of mobile mapping system images. The acquired images are still a significant source of temporal condition of thepavement surface. The automatisation of crack detection is highly necessarybecause it could decrease workload, and therefore, maintenance costs. Two methods for automatic crack detection from mobile mapping imageswere tested: step by step pixel based image intensity analysis, and deep learning. The objective of this thesis is to develop and test the workflow for the streetview image crack detection and reduce image database by detecting no-cracksurfaces. To examine the performance of the methods, their classification precisionwas compared. The best-acquired precision with the trained deep learningmodel was 98% that is 3% better than with the other method and it suggeststhat the deep learning is the most appropriate for the application. Furthermore, there is a need for faster and more precise detection methods, and deep learningholds promise for the further implementation. However, future studies areneeded and they should focus on full-scale image crack detection, disturbingobject elimination and crack severity classification.
37

Vytěžování snímků z panoramatické kamery mobilního mapování / Exploitation of images from panoramatic camera of mobile mapping system

Belanis, Pavel January 2019 (has links)
This diploma thesis deals with an automated detection of vertical traffic signs in images from the panoramic camera Ladybug5. From the detected signs with help of a classifier, a GIS data set is automatically created, usable for example to passportisation of traffic signs. The first part of the thesis describes a theoretical basis needed to understand the given problematics. The second part is devoted to a specific procedure leading to the reliable classifier, its testing on an independent set of images and automated creation of the GIS data set. The output of the work are the trained classifiers and the GIS data sets containing vertical traffic signs.
38

U - Net Based Crack Detection in Road and Railroad Tunnels Using Data Acquired by Mobile Device / U - Net - baserad sprickdetektering i väg - och järnvägstunnlar med hjälp av data som förvärvats av mobil enhet

Gao, Kepan January 2022 (has links)
Infrastructures like bridges and tunnels are significant for the economy and growth of countries, however, the risk of failure increases as they getting aged. Therefore, a systematic monitoring scheme is necessary to check the integrity regularly. Among all the defects, cracks are the most common ones that can be observed directly by camera or mapping system. Meanwhile, cracks are capable and reliable indicators. As a result, crack detection is one of the most broadly researched topic. As the limitation of computing resource vanishing, deep learning methods are developing rapidly and used widely. U-net is one of the latest deep learning methods for image classification and has shown overwhelming adaptability and performance in medical images. It is promising to be capable for crack detection.  In this thesis project, a U-net approach is used to automatically detect road and tunnel cracks. An open-source crack detection dataset is used for training. The model is improved by new parameter settings and fine-tuning and transformed onto the data acquired by the mobile mapping system of TACK team. Image processing techniques such as class imbalance handling and center line are also used for improvement. At last, qualitative and quantitative statistics are used to illustrate superiority of the methods.  This thesis project is a sub-project of project TACK, which is an ongoing research project carried out by KTH - Royal Institute of Technology, Sapienza University of Rome and WSP Sweden company under the InfraSweden2030 program funded by Vinnova. The main objective of TACK is developing a methodology for automatic detection and measurement of cracks on tunnel linings or other infrastructures.
39

Automatic Point Cloud Registration for Mobile Mapping LiDAR Data : Developing an Automated Method for Registration of Light Rail Environment / Automatisk registrering av punktmoln från Mobile Mapping LiDAR data : Framställning av en automatisk metod för registrering i spårvägsmiljö

Larsson, Milton, Wardman, Ellinor January 2024 (has links)
Maintaining an inventory of transportation infrastructure assets is vital for effective management and maintenance. LiDAR (Light Detection and Ranging) can be a useful resource for this purpose by collecting detailed 3D information. Mobile Mapping Systems (MMS) refers to collecting geospatial data by mounting laser scanners on top of a moving vehicle, e.g. a car. The LiDAR collects XYZ-coordinates of the environment by emitting laser pulses toward the surveyed objects. This enables an effective way to store and survey built-up urban areas that otherwise would need an on-site presence. WSP uses Mobile Mapping (MM) to capture and visualize infrastructure, primarily for inventory purposes. Currently, the point cloud registration in the MM-process is labor-intensive, so the company is looking to automate it. This thesis aims to investigate methods to automate the process of point cloud registration that eliminates manual labor. The proposed method was evaluated with regards to its accuracy, advantages and disadvantages. The study area of the thesis was a light rail facility with surrounding residential buildings and vegetation. The proposed method was implemented in Python and utilizes open source libraries. The registration uses Fast Global Registration (FGR) for coarse alignment with Iterative Closest Point (ICP) for fine refinement. The FGR algorithm finds a rigid transformation between a pair of point clouds by establishing a feature correspondence set between the point clouds. The algorithm utilizes Fast Point Feature Histograms (FPFH) that simplifies the description of 3D point relationships as the feature descriptors. The object used for registration is the general area around catenary poles. The segments between poles is adjusted by linear interpolation of the obtained transformation matrices from the registration. The results of this thesis show that automatic point cloud registration is feasible. However, while the proposed method improves registration over raw data, it does not fully replace WSP's current procedure.  The advantages of the proposed method are that it does not require classified data and is open source. The main source of error in the method is the presence of vegetation, and an experiment was conducted to support this hypothesis. The experiment shows that dense vegetation skews the registration, and generates an incorrect transformation matrix. Furthermore, the proposed method is only semi-automated, as it still needs manual post-processing. Accuracy assessment showed that removing outlier, presumably caused by vegetation, improved the planar offsets. Further studies to improve the result could utilize machine learning which could identify and extract poles for registration or remove surrounding vegetation. / Att upprätthålla inventering av tillgångar av transportinfrastruktur är avgörande för effektiv förvaltning och underhåll samt för att tillhandahålla korrekta data och underlätta beslutsfattande. LiDAR-data (Light Detection and Ranging) kan vara ett användbart verktyg för detta ändamål genom att samla in detaljerad 3D-information. Mobile Mapping Systems (MMS) refererar till att samla geospatial data genom att montera laserskannrar ovanpå taket på ett rörligt fordon, exempelvis en bil. LiDAR samlar XYZ-koordinater av kringliggande miljö genom att sända ut laserpulser mot de undersökta objekten. Detta möjliggör ett effektivt sätt att förvara och undersöka bebyggda stadsmiljöer som annars skulle behöva fysisk närvaro. WSP använder Mobile Mapping (MM) för att samla och visualisera infrastruktur, främst för inventeringsändamål. För närvarande är punktmolnregistreringen i MM-processen manuellt arbetskrävande, och därför vill WSP se en automatisering av processen. Detta examensarbete syftar till att undersöka metoder för att automatisera processen för registrering av punktmoln som eliminerar manuellt arbete. Den utvecklade metoden kommer att utvärderas med avseende på dess noggrannhet, för- och nackdelar. Arbetets studieområde är en järnvägsanläggninng med omgivande av bostadshus och vegetation. Den föreslagna metoden implementerades i Python och använder sig av open source-bibliotek. Registeringen tillämpar Fast Global Registration (FGR) för grov justering av punktmolnen, och Iterative Closest Point (ICP) för finjustering. FGR-algoritmen hittar en stel transformation mellan två punktmoln genom att etablera ett set av korresponderande attribut. Algoritmen använder Fast Point Feature Histograms (FPFH) som förenklar euklidiska förhållanden till attributbaserade förhållanden. Objekt som används för registrering är det generella området kring kontaktledningsstolpar. Segmenten mellan stolpar justeras genom linjär interpolation av de erhållna transformationsmatriserna från registreringen. Resultaten av detta arbete visar att automatisk registrering av punktmoln är genomförbar, och att metoden förbättrar registreringen jämfört med den råa datan. Den är dock inte tillräckligt bra för att helt ersätta den nuvarande proceduren som används av WSP. Fördelarna med den föreslagna metoden är att den inte kräver klassificerad data och är open source. Den huvudsakliga felkällan i metoden är förekomsten av vegetation, och ett experiment utfördes för att stödja denna hypotes. Experimentet visar att tät vegetation snedvrider registreringen och genererar en felaktig transformationsmatris. Vidare, är den föreslagna metoden endast semi-automatiserad, eftersom den fortfarande kräver manuell efterbearbetning. Noggrannhetsbedömningn visade att borttagningen av avvikande värden, förmodligen orsakade av vegetation, förbättrade den plana förskjutningen. Vidare studier för att ge ett mer tillfredsställande resultatet kan möjligen vara att använda maskininlärning för att identifiera och extrahera stolpar för matching, samtidigt som växtligheten kan elimineras.
40

Roadmark reconstruction from stereo-images acquired by a ground-based mobile mapping system

Soheilian Khorzoughi, Bahman 01 April 2008 (has links) (PDF)
Despite advances in ground-based Mobile Mapping System (MMS), automatic feature reconstruction seems far from being reached. In this thesis, we focus on 3D roadmark reconstruction from images acquired by road looking cameras of a MMS stereo-rig in dense urban context. A new approach is presented, that uses 3D geometric knowledge of roadmarks and provides a centimetric 3D accuracy with a low level of generalisation. Two classes of roadmarks are studied: zebra-crossing and dashed-lines. The general strategy consists in three main steps. The first step provides 3D linked-edges. Edges are extracted in the left and right images. Then a matching algorithm that is based on dynamic programming optimisation matches the edges between the two images. A sub-pixel matching is computed by post processing and 3D linked-edges are provided by classical photogrammetric triangulation. The second step uses the known specification of roadmarks to perform a signature based filtering of 3D linked-edges. This step provides hypothetical candidates for roadmark objects. The last step can be seen as a validation step that rejects or accepts the candidates. The validated candidates are finely reconstructed. The adopted model consists of a quasi parallelogram for each strip of zebra-crossing or dashed-line. Each strip is constrained to be flat but the roadmark as a whole is not planar. The method is evaluated on a set of 150 stereo-pairs acquired in a real urban area under normal traffic conditions. The results show the validity of the approach in terms of robustness, completeness and geometric accuracy. The method is robust and deals properly with partially occluded roadmarks as well as damaged or eroded ones. The detection rate reaches 90% and the 3D accuracy is about 2-4 cm. Finally an application of reconstructed roadmarks is presented. They are used in georeferencing of the system. Most of the MMSs use direct georeferencing devices such as GPS/INS for their localisation. However in urban areas masks and multi-path errors corrupt the measurements and provide only 50 cm accuracy. In order to improve the localisation quality, we aim at matching ground-based images with calibrated aerial images of the same area. For this purpose roadmarks are used as matching objects. The validity of this method is demonstrated on a zebra-crossing example

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