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Titre : Calibration of a terrestrial laser scanner for engineering geodesy Type de document : Thèse/HDR Auteurs : Thorsten Schulz, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2008 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 96 Importance : 158 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-71-9 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] angle d'incidence
[Termes IGN] balayage laser
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] erreur instrumentale
[Termes IGN] étalonnage d'instrument
[Termes IGN] semis de points
[Termes IGN] télémètre laser terrestre
[Termes IGN] traitement automatique de donnéesIndex. décimale : 35.10 Acquisition d'images Résumé : (Auteur) For several years now, terrestrial laser scanning has become an additional surveying technique in geodesy. Recent developments have improved several aspects of terrestrial laser scanners, e.g. the data acquisition rate, accuracy, and range. Since such instruments are relatively new and constructed by manufacturers who do not have advanced experience in surveying instruments, investigations are needed to assess the quality of the instrumental characteristics and the acquired data. In this way, manufacturers will understand the needs of geodesists and in turn enable geodesists to provide the necessary support in the development of improvements. This thesis has three objectives, the calibration and investigation of a terrestrial laser scanner, the post-processing of point clouds acquired by laser scanners, and applications of terrestrial laser scanning.
The first objective is a comprehensive calibration and investigation of a specific laser scanner, the Imager 5003 of Zoller+Frohlich GmbH (Germany). The investigation and calibration procedures shall give a general impulse for all users of terrestrial laser scanning regarding instrumental and non-instrumental errors, the assessment of the quality of distance and angle measurements, and the influencing parameters. Laser scanners are a black box instrument that produces a huge number of 3D points in the form of a point cloud in a short time. However, it is the surveyor, who has to assess the reliability and quality of the resulting data. Therefore, the potential and the limitations of laser scanner systems must be identified. This is particularly important when a distance measurement is influenced by several parameters that can bias the data. Since laser scanning is an active surveying method, mostly independent of lighting conditions, distance measurements do not require prisms. Thus, surveying of almost every object is conceivable.
The second objective involves post-processing of the point clouds. Terrestrial laser scanning consists not only of data acquisition, but also processing of the acquired 3D data, which include an intensity value of the reflected laser beam. The point clouds define the objects and the data contains nearly all the information about the objects due to the high sampling interval of laser scanners. To produce the final result, data processing needs to be completed and this can be quiet involving, e.g. registration, data filtering, noise reduction, triangulation, and modeling. The ratio between post-processing and data acquisition can be 10:1 or greater, which means ten (or more) days of post-processing follow one day of data acquisition. This aspect of post-processing applies for both static laser scanning and kinematic laser scanning. The only difference is that kinematic laser scanning requires an unique method of registration and geo-referencing.
The third objective examines the applications of terrestrial laser scanning. Laser scanning can be used in different fields of applications, e.g. industrial metrology, cultural heritage, reverse engineering, and engineering geodesy. Due to the increased requirements regarding accuracy engineering geodesy appears to be a challenging field. Therefore, three different applications are presented which verify the successful use of terrestrial laser scanning in engineering geodesy. The first application involves the field of urban water management. A road surface was scanned to derive catchment areas and water flow directions. The second application covers the field of engineering geology. A tunnel during and after excavation was scanned to characterize rock mass structures and to derive displacement maps of surfaces and object points. Since the first two applications are based on static laser scanning, which means the laser scanner did not change in position and orientation during scanning, the third application is a kinematic one, which means the laser scanner was in motion during scanning. Such kinematic applications are of great interest since the performance of laser scanning can be increased significantly. Tunnels and roads are especially appropriate for kinematic laser scanning. The potential of kinematic laser scanning is tested by moving the laser scanner along a track line. The quality is assessed by scanning reference points.Note de contenu : 1 Introduction
1.1 Terrestrial Laser Scanning
1.2 Motivation
1.3 Outline
2 Components of Terrestrial Laser Scanner
2.1 Distance and Reflectance Measurement System
2.1.1 Electromagnetic Waves
2.1.2 Laser
2.1.3 Direct Time-of-Flight
2.1.4 Amplitude-Modulated Continuous Wave (AMCW)
2.1.5 Frequency-Modulated Continuous Wave (FMCW)
2.1.6 Overview of Distance Measurement Techniques in Terrestrial Laser Scanners
2.1.7 Avalanche Photo Diode (APD)
2.1.8 Reflection Principles
2.1.9 Reflectance Models
2.2 Angle Measurement System
2.2.1 Incremental Encoding
2.2.2 Binary Encoding
2.3 Deflection System
2.3.1 Oscillating Mirror
2.3.2 Rotating Mirror
2.3.3 Overview of Deflection Techniques in Terrestrial Laser Scanners
3 Calibration of Terrestrial Laser Scanner
3.1 Laboratories and Tools for Calibration
3.1.1 Calibration Track Line
3.1.2 Test Field of Control Points
3.1.3 Test Field of Observation Pillars
3.1.4 Electronic Unit for Frequency Measurement
3.1.5 Calibration of Spheres
3.2 Distance Measurement System
3.2.1 Static Mode
3.2.2 Scanning Mode
3.2.3 Long-Term Stability
3.2.4 Frequency Stability
3.3 Angle Measurement System
3.3.1 Horizontal Encoder
3.3.2 Vertical Encoder
3.3.3 Angular Resolution
3.4 Instrumental Errors
3.4.1 Eccentricity of Scan Center
3.4.2 Wobble of Vertical axis
3.4.3 Error of Collimation Axis
3.4.4 Error of Horizontal Axis
3.5 Non-Instrumental Errors
3.5.1 Intensity of Laser Beam
3.5.2 Angle of Incidence
3.5.3 Surface Properties of Materials
3.6 Precision and Accuracy of Terrestrial Laser Scanner Data
3.6.1 Single Point Precision
3.6.2 Accuracy of Modeled Objects (Spheres)
4 Static Laser Scanning
4.1 Data Processing
4.1.1 Blunder Detection
4.1.2 Mixed Pixel
4.1.3 Range/Intensity Crosstalk .
4.1.4 Multipath
4.1.5 Noise Reduction
4.2 Registration
4.2.1 Target-Based Registration
4.2.2 Point Cloud Registration
4.3 Modeling and Visualization
4.3.1 Geometrical Primitives
4.3.2 Triangulation
4.3.3 NURBS
4.3.4 CAD
4.3.5 Rendering and Texture Mapping
5 Kinematic Laser Scanning
5.1 Test Trolley on Calibration Track Line
5.1.1 Relative Position and Orientation
5.1.2 Absolute Position and Orientation
5.2 Rotation Time of Rotating Mirror of Laser Scanner
5.2.1 Direct Method
5.2.2 Indirect Method
5.2.3 Discussion and Comparison
5.3 Position-Fixing Using Total Station
5.3.1 Blunder Detection and Smoothing
5.3.2 Polynomial Interpolation
5.3.3 Regression Line
5.3.4 Kalman Filtering
5.4 Synchronisation
6 Applications of Terrestrial Laser Scanning
6.1 Static Application: Road Surface Analysis
6.1.1 Introduction
6.1.2 Method.
6.1.3 Results
6.2 Static Application: Rock Engineering Applications
6.2.1 Introduction
6.2.2 Method.
6.2.3 Results
6.3 Kinematic Application: Test Tunnel
6.3.1 Introduction
6.3.2 Kinematic Model: Regression Line
6.3.3 Kinematic Model: Kalman Filter
6.3.4 Results
7 Summary
7.1 Conclusions
7.2 OutlookNuméro de notice : 13652 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère En ligne : http://dx.doi.org/10.3929/ethz-a-005368245 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62557 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13652-01 35.10 Livre Centre de documentation En réserve M-103 Disponible La caune de l'Arago / Floryne Roche (2008)
Titre : La caune de l'Arago : intégration des parois dans les profils et perspectives Type de document : Mémoire Auteurs : Floryne Roche, Auteur Editeur : Champs-sur-Marne : Ecole nationale des sciences géographiques ENSG Année de publication : 2008 Importance : 161 p. Format : 21 x 30 cm Note générale : Bibliographie
Rapport de projet pluridisciplinaire, cycle des ingénieurs diplômés de l'ENSG 2ème année (IT2)Langues : Français (fre) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données laser
[Termes IGN] grotte
[Termes IGN] lasergrammétrie
[Termes IGN] logiciel libre
[Termes IGN] modélisation 3D
[Termes IGN] profil
[Termes IGN] QGIS
[Termes IGN] site archéologique
[Termes IGN] TautavelIndex. décimale : PROJET Mémoires : Rapports de projet - stage des ingénieurs de 2e année Résumé : (Auteur) Le Centre Européen de Recherches Préhistorique de Tautavel (CERPT) compte en son sein une vingtaine de chercheurs étudiant le matériel archéologique extrait de la Caune de l'Arago. Afin de permettre l'étude des différents sols archéologiques de la grotte, ils réalisent des projections sur un plan vertical du matériel archéologique présent dans une bande de sédiment d'une épaisseur de 10 cm. L'étude ne peut être complète sans la visualisation dans ces coupes des parois de la grotte. Les données laser acquises en Octobre 2007 à l'intérieur de la grotte doivent donc être intégrées dans la base de données, prévue à l'origine uniquement pour accueillir des points, et visualisées en même temps que le matériel archéologique. L'application utilisée par les chercheurs ne convenait pas pour une telle visualisation. D'autres logiciels ont donc été étudiés, et la base de données modifiée pour permettre, d'une part l'intégration des parois dans la base, et d'autre part, la visualisation du matériel archéologique avec le logiciel choisi. Si les résultats de visualisation sont concluants, il reste encore à transformer la base de données principale pour y apporter les modifications réalisées dans une copie. Un des buts du CERPT est, à terme, l'obtention d'une modélisation 3D de l'environnement de la grotte. Une première étude des différentes méthodes disponibles pour réaliser l'acquisition de données à l'extérieur de la cavité a été réalisée, mais le choix de l'une des techniques et la résolution d'acquisition des données devront être définies précisément par le biais d'une concertation des différents acteurs. Note de contenu : INTRODUCTION
1° CONTEXTE
environnement
objectifs du stage
l'existant
Les données laser
La base de données
GenMap
etudes realisees, en cours et a venir
2° LE CARROYAGE
La longitudinale
precision attendue
3° INTEGRATION DES PAROIS DANS LES EXTRACTIONS DE MATERIEL ARCHEOLOGIQUE
coupes sous cumulus
Nuages de points
Plan de référence
Plan de coupe
nettoyage des coupes
etude des logiciels de visualisation
transformations de la base de donnees
Modifications apportées sur les parois
Modifications apportées aux objets
resultat
4° EXTERIEUR DE LA GROTTE
La demande
etude des moyens techniques
CONCLUSIONNuméro de notice : 13712 Affiliation des auteurs : IGN (1940-2011) Thématique : IMAGERIE Nature : Mémoire de projet pluridisciplinaire Organisme de stage : Centre Européen de Recherches Préhistoriques de Tautavel Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=50107 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13712-01 PROJET Livre Centre de documentation Travaux d'élèves Disponible Entwicklung eines Qualitätsmodells für die Generierung von digitalen Gelandemodellen aus airborne Laser scanning / Hans Jürg Luthy (2008)
Titre : Entwicklung eines Qualitätsmodells für die Generierung von digitalen Gelandemodellen aus airborne Laser scanning Titre original : [Développement d'un modèle de qualité pour générer des modèles numériques de terrain à partir de télémétrie laser aéroportée] Type de document : Thèse/HDR Auteurs : Hans Jürg Luthy, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2008 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 95 Importance : 140 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-70-2 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données lidar
[Termes IGN] géoréférencement direct
[Termes IGN] GPS en mode différentiel
[Termes IGN] GPS-INS
[Termes IGN] indicateur de qualité
[Termes IGN] mesure de la qualité
[Termes IGN] modèle numérique de surface
[Termes IGN] modèle numérique de terrain
[Termes IGN] qualité des données
[Termes IGN] spécification
[Termes IGN] télémétrie laser aéroporté
[Termes IGN] test de performanceIndex. décimale : 35.20 Traitement d'image Résumé : (Auteur) Airborne Laser Scanning (ALS) has become the most important technology in Europe to acquire high resolution Digital Elevation Models (DEM). Compared to the well established Photogrammetry ALS allows an increased efficiency due to direct georeferencing and direct determination of 3D coordinates. The dense point spacing and the possibility to acquire simultaneous Digital Terrain (DTM) and Digital Surface Models (DSM) are additional benefits. Some of the drawbacks of ALS are known from other methods to acquire spatial data: the abstraction of the real world in a data model is strongly influenced by the impossibility to validate the quality of data acquisition by the use of on set of reference data. As a matter of fact only partial verification of single characteristics is performed using adequate methods or reference information. A well known example for this is the determination of vertical accuracy using ground control points.
The two main disadvantages compared to Photogrammetry are the number of involved sensors and the unstructured data capturing during the scanning process. The former leads - in combination with the separation in different data processing activities - to a delayed discovery of faults in the data acquisition. Not captured features (completeness of data acquisition) are often detected later on in the feature extraction. Whilst for other survey methods quality measures had been developed over years, standards or guidelines for ALS with appropriate quality indicators and test methods are still missing. The separation between the determination of coordinates in the unstructured data acquisition and the feature extraction during point classification may have a negative impact on the data quality. The use of the spatial accuracy as the dominant indicator to measure the quality of a DEM is not suited to detect errors in the point classification. Delays and excessive costs in many projects are the consequence of this lack of complete specifications if a principal conducts thorough visual inspection of the deliverables.
This thesis introduces a quality model which eliminates the above listed shortcomings. In a holistic approach sensors, algorithms and processes are examined on their impact on spatial data described. The quality model is built up on the requirements set forth in the ISO standards for quality management and for spatial data but is also taking into account the (unique) properties of the ALS technology and the sensitive customer relationship. The core element of the model is the product specification where the representation of the real world in the spatial data set is defined. The non-quantitative quality element is completed by the Meta data further information to allow traceability. To the second layer of the quality model belong various components to describe the quantitative quality indicators. By extending the elements from currently used spatial accuracy and point spacing all user requirements can be captured in technical specifications. The benefit can only be achieved if appropriate test methods and the acceptable conformance quality level are defined. The thesis does not attempt to define a minimum acceptable level of quality for DEMs since they strongly depend on individual user requirements but proposes ideas how the quality elements may be used. The third layer then defines requirements for process quality. Here it is distinguished between the processes for product realisation and management processes. The activities on the technical side directly impact the quality of the products and include inter alia sensor system, data processing, verification and documentation. The mid and long term quality of the products and realisation processes is achieved through the management processes. Special attendance is needed for data management due to the huge volume of data. As the outcome of the three inner layers the outermost contains finally the spatial data sets according to product definitions and technical specifications.
The complexity of the processes and the data volume requires suitable software tools, particularly for larger projects. A high level system architecture and the base functionality of such a production suite for ALS are outlined and the positive effects in the production due to increased efficiency and effectivity are demonstrated.
The benefits and the advantages of the quality model in the practical application are discussed on a large project for the Federal Office of Topographic (swisstopo).Note de contenu : l Einführung
1.1 Ausgangslage und Motivation
1.2 Ziel der Arbeit
1.3 Gliederung der Arbeit
1.4 Qualitäts- und Prozessmanagement
1.4.1 Erläuterung zum Begriff Qualität
l .4.2 Grundzüge des Qualitätsmanagements
1.4.3 Prozesse
1.4.4 Qualitätsplanung
1.4.5 Qualitätsmanagement bei ALS-Projekten
1.5 Qualität im Vermessungswesen
1.6 Qualität von Geodäten
1.6.1 Produktmerkmale
1.6.2 Allgemeine Qualitätsmerkmale von Geodäten
1.6.3 Die Qualitätsmerkmale der ISO Geonormen
1.6.4 Der Prozess der Qualitätsprüfung
1.6.5 Dokumentation der Qualitätsinformation
1.7 Qualität von Digitalen Geländemodellen
1.7.1 Begriffe
1.7.2 Modellierungsprozesse
1.7.3 Klassische Qualitätsmerkmale von DGM
2 Datenerfassung mittels Airborne Laser Scanning
2.1 Laser Scanner/
2.1.1 Laser Impuls
2.1.2 Ablenktechnologie
2.2 Positionierungs- und Orientierungssystem
2.2.1 Kinematisches DGPS
2.2.2 Inertiales Messsystem
2.2.3 Kombination der POS-Messgrössen
2.3 Vergleich der gebräuchlichsten ALS-Systeme
2.4 Unsicherheiten in der Datenerfassung
2.4. l Unsicherheit der Objekterfassung
2.4.2 Messunsicherheit in der Rangebestimmung
2.4.3 Messunsicherheit der Winkelbestimmung
2.4.4 Messunsicherheit der Positions- und Orientierungsbestimmung
2.4.5 Kombinierte Messunsicherheit
2.4.6 Anmerkung zur kombinierten Messunsicherheit
2.5 Bestimmung und Reduktion von systematischen Einflüssen
2.5. l Labor-Kalibrierung Laser Scanner
2.5.2 In situ Systemkalibrierung
2.5.3 Streifenausgleichung
2.6 Diskussion
3 Die ALS-Prozesskette
3.1 Produktspezifikation
3.2 Flugplanung
3.3 Flugvorbereitung und Systemkalibrierung
3.4 Befliegung 3.5 Berechnen der externen Orientierung
3.6 Prozessieren der Rohdaten
3.7 Filterung der Punkte
3.8 Modellbildung
3.9 Metadaten und Datenabgabe
3.10 Datensätze
3.10.1 Daten für die Planung und Vorbereitung der Arbeiten
3.10.2 Befliegung
3.10.3 Prozessieren der Rohdaten
3.10.4 Filterung der Punktwolke
3.10.5 Unterstützende Daten
3.10.6 Prozess-Aufzeichnungen
3.10.7 Qualitätskontrollen
3.11 Unsicherheiten in und aus den Prozessen
3.11.1 Umgang mit Ausreissern in der Rangebestimmung
3.11.2 Abweichungen und Fehler bei Terrain-Filterung
3.11.3 Unsicherheit aus der Modellierung
3.12 Diskussion
4 Qualitätsmodell für Airborne Laser Scanning
4.1 Aufbau des ALS-Qualitätsmodells
4.2 Nicht-quantitative Qualitätselemente
4.2.1 Allgemeine Produktdefinitionen für DGM
4.2.2 Definition des Produkts „DTM"
4.2.3 Definition des Produkts „DOM",
4.2.4 Nachvollziehbarkeit und Metadaten '
4.3 Quantitative Qualitätselemente (technischen Spezifikationen),
4.3.1 Auflösung
4.3.2 Räumliche Genauigkeit
4.3.3 Thematische Genauigkeit
4.3.4 Vollständigkeit
4.3.5 Zeitliche Genauigkeit
4.3.6 Logische Konsistenz
4.3.7 Vorschlag für technische Spezifikationen
4.4 Prozessqualität
4.5 Realisierungsprozesse
4.6 Managementprozesse
4.6.1 Projektmanagement
4.6.2 Kontinuierliche Verbesserung
4.6.3 Ausbildung und Training
4.6.4 Know-how Management
4.7 Qualitätsprüfung
4.7.1 Methoden der Qualitätsprüfungen
4.7.2 Kontrollen im Prozessablauf
4.7.3 Werkzeuge zur Qualitätskontrolle
4.7.4 Aufzeichnung der Qualitätsprüfung
4.8 Datenmanagement
4.9 Produktionssystem für ALS
4.9.1 Modul Qualitätssicherung und Visuelle Kontrolle
4.9.2 Modul Produktionsmonitoring
4.9.3 Modul Prozess-Manager
5 Analyse und Verbesserungsmöglichkeiten aus dem Projekt Landwirtschaftliche Nutzfläche
5.1 Einführung zum Projekt
5.2 Erarbeiten der Spezifikationen
5.3 Datenerfassung
5.3.1 Flugplanung
5.3.2 Schwierigkeiten in der Befliegung
5.3.3 Erkenntnisse aus der Datenerfassung im alpinen Raum
5.4 Prozessieren der Messwerte
5.4.1 Ableiten der Punktwolke aus den Messungen
5.4.2 Klassifizierung der Punkte
5.4.3 Ausbildung
5.4.4 ALS-Produktionssystem
5.5 Qualitätsmanagement
5.5.1 Kontrolle während der Befliegung
5.5.2 Kontrolle der Datenerfassung
5.5.3 Visuelle Kontrolle der Endprodukte
5.5.4 Resultate der quantitativen Qualitätsprüfungen
5.6 Diskussion der Erkenntnisse aus dem Projekt LWN
6 Schlussfolgerungen und Ausblick
6.1 Schlussfolgerungen
6.2 Ausblick
6.2.1 Monitoring des Scannens
6.2.2 Automatische Selektion der optimalen Punkte im Übeflappungsbereich
6.2.3 Filterung der Terrainpunkte
6.2.4 Echtzeit-DatenauswertungNuméro de notice : 13651 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-005396321 En ligne : http://dx.doi.org/10.3929/ethz-a-005396321 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62556 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13651-01 35.20 Livre Centre de documentation Télédétection Disponible
Titre : EuroSDR ISPRS project, commission 2 tree extraction: final report Type de document : Rapport Auteurs : Harri Kaartinen, Auteur ; Juha Hyyppä, Auteur ; European Spatial Data Research EuroSDR, Auteur Editeur : Dublin : European Spatial Data Research EuroSDR Année de publication : 2008 Collection : EuroSDR official publication, ISSN 0257-0505 num. 53 Importance : 60 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-90-5179-598-X Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] analyse comparative
[Termes IGN] arbre (flore)
[Termes IGN] canopée
[Termes IGN] données lidar
[Termes IGN] étude de faisabilité
[Termes IGN] extraction automatique
[Termes IGN] extraction du sursol
[Termes IGN] extraction semi-automatique
[Termes IGN] forêt
[Termes IGN] hauteur des arbres
[Termes IGN] image aérienne
[Termes IGN] lasergrammétrie
[Termes IGN] qualité des donnéesIndex. décimale : 35.20 Traitement d'image Résumé : (Auteur) The objective of the EuroSDR/ISPRS Tree Extraction project was to evaluate the quality, accuracy, and feasibility of automatic or semi-automatic tree extraction methods based on high-density laser scanner data and digital image data. Data sets from two test sites were delivered to the twelve participants of the project. For each test site the following data were available and could be downloaded from the FGI ftp-site: aerial images, camera calibration and image orientation information, ground control point coordinates and jpg-images of point locations, laser scanner data with three different pulse densities, digital terrain model and a training data set. In this report the test sites used, data sets and the reference data are described. The tree extraction methods used by the participants and methods used in accuracy evaluation are explained in this report. The produced tree models are depicted and analysed with respect to tree location, tree height, crown base height and crown delineation accuracy. Finally, a discussion and conclusions chapter summarise the results of the project. Surprisingly, results show that the extraction method is the main factor on the achieved accuracy. When the laser point density increases from two points to eight points per m2, the improvement in crown base height and crown delineation accuracy is marginal but in the case of some methods the accuracy of the tree location and especially the tree height determination improves. The low number of hybrid models based on both the laser data and aerial image produced by the partners implies that integration of laser and aerial image is in its early stages. Numéro de notice : 15391 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Rapport En ligne : http://www.eurosdr.net/sites/default/files/uploaded_files/eurosdr_publication_nd [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=40674 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15391-01 35.20 Livre Centre de documentation Télédétection Disponible Geometric validation of a ground-based mobile laser scanning system / D. Barber in ISPRS Journal of photogrammetry and remote sensing, vol 63 n° 1 (January - February 2008)
[article]
Titre : Geometric validation of a ground-based mobile laser scanning system Type de document : Article/Communication Auteurs : D. Barber, Auteur ; Jon Mills, Auteur ; S. Smith-Voysey, Auteur Année de publication : 2008 Article en page(s) : pp 128 - 141 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Topographie
[Termes IGN] données laser
[Termes IGN] données localisées 3D
[Termes IGN] lasergrammétrie
[Termes IGN] lever topographique
[Termes IGN] milieu urbain
[Termes IGN] outil d'aide à la décision
[Termes IGN] précision des données
[Termes IGN] semis de points
[Termes IGN] système de numérisation mobile
[Termes IGN] validité des donnéesRésumé : (Auteur) This paper outlines a study, carried out on behalf of a national mapping agency, to validate laser scanned point cloud data collected by a ground-based mobile mapping system. As the need for detailed three-dimensional data about our environment continues to grow, ground-based mobile systems are likely to find an increasingly important niche in national mapping agency applications. For example, such systems potentially provide the most efficient data capture for numerical modelling and/or visualisation in support of decision making, filling a void between static terrestrial and mobile airborne laser scanning. This study sought to assess the precision and accuracy of data collected using the StreetMapper system across two test sites: a peri-urban residential housing estate with low density housing and wide streets, and a former industrial area consisting of narrow streets and tall warehouses. An estimate of system precision in both test sites was made using repeated data collection passes, indicating a measurement precision (95%) of between 0.029 m and 0.031 m had been achieved in elevation. Elevation measurement accuracy was assessed against check points collected using conventional surveying techniques at the same time as the laser scanning survey, finding RMS errors in elevation in the order of 0.03 m. Planimetric accuracy was also assessed, with results indicating an accuracy of approximately 0.10 m, although difficulties in reliably assessing planimetric accuracy were encountered. The results of this validation were compared against a theoretical error pre-analysis which was also used to show the relative components of error within the system. Finally, recommendations for future validation methodologies are outlined and possible applications of the system are briefly discussed. Copyright ISPRS Numéro de notice : A2008-041 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2007.07.005 En ligne : https://doi.org/10.1016/j.isprsjprs.2007.07.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29036
in ISPRS Journal of photogrammetry and remote sensing > vol 63 n° 1 (January - February 2008) . - pp 128 - 141[article]Réservation
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