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A pipeline of 3D scene reconstruction from point clouds / Lingli Zhu (2015)  

Public Titre : A pipeline of 3D scene reconstruction from point clouds Type de document : Thèse/HDR Auteurs : Lingli Zhu, Auteur ; Henrik Haggren, Directeur de thèse Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 2015 Collection : Publications of the Finnish Geodetic Institute, ISSN 0085-6932 num. 157 Importance : 206 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-48-0246-1 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] base de données topographiques [Termes IGN] détection d'objet [Termes IGN] détection du bâti [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] reconstruction 3D du bâti [Termes IGN] reconstruction de route [Termes IGN] réseau routier Résumé : (auteur) 3D technologies are becoming increasingly popular as their applications in industrial, consumer, entertainment, healthcare, education, and governmental increase in number. According to market predictions, the total 3D modeling and mapping market is expected to grow from $1.1 billion in 2013 to $7.7 billion by 2018. Thus, 3D modeling techniques for different data sources are urgently needed. This thesis addresses techniques for automated point cloud classification and the reconstruction of 3D scenes (including terrain models, 3D buildings and 3D road networks). First, georeferenced binary image processing techniques were developed for various point cloud classifications. Second, robust methods for the pipeline from the original point cloud to 3D model construction were proposed. Third, the reconstruction for the levels of detail (LoDs) of 1-3 (CityGML website) of 3D models was demonstrated. Fourth, different data sources for 3D model reconstruction were studied. The strengths and weaknesses of using the different data sources were addressed. Mobile laser scanning (MLS), unmanned aerial vehicle (UAV) images, airborne laser scanning (ALS), and the Finnish National Land Survey’s open geospatial data sources e.g. a topographic database, were employed as test data. Among these data sources, MLS data from three different systems were explored, and three different densities of ALS point clouds (0.8, 8 and 50 points/m2) were studied. The results were compared with reference data such as an orthophoto with a ground sample distance of 20cm or measured reference points from existing software to evaluate their quality. The results showed that 74.6% of building roofs were reconstructed with the automated process. The resulting building models provided an average height deviation of 15 cm. A total of 6% of model points had a greater than one-pixel deviation from laser points. A total of 2.5% had a deviation of greater than two pixels. The pixel size was determined by the average distance of input laser points. The 3D roads were reconstructed with an average width deviation of 22 cm and an average height deviation of 14 cm. The results demonstrated that 93.4% of building roofs were correctly classified from sparse ALS and that 93.3% of power line points are detected from the six sets of dense ALS data located in forested areas. This study demonstrates the operability of 3D model construction for LoDs of 1-3 via the proposed methodologies and datasets. The study is beneficial to future applications, such as 3D-model-based navigation applications, the updating of 2D topographic databases into 3D maps and rapid, large-area 3D scene reconstruction. Numéro de notice : 21975 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Thèse étrangère Note de thèse : Doctoral thesis : Geoinformatics : Aalto university : 2015 En ligne : https://aaltodoc.aalto.fi/bitstream/handle/123456789/16214/isbn9789514802478.pdf [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93653

Analysing landmarks in nature and elements of geospatial images to support wayfinding / Pyry Kettunen (2014)  

Public Titre : Analysing landmarks in nature and elements of geospatial images to support wayfinding Type de document : Thèse/HDR Auteurs : Pyry Kettunen, Auteur Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 2014 Collection : Publications of the Finnish Geodetic Institute, ISSN 0085-6932 num. 155 Importance : 150 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-711-312-0 Note générale : bibliographie Doctoral dissertation for the degree of Doctor of Science in Technology (Doctor of Philosophy) to be presented with due permission of the School of Engineering for public examination and debate in Auditorium M1 at the Aalto University School of Engineering (Espoo, Finland) on the 4th of October 2014 at 12 noon. Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] carte en 3D [Termes IGN] croquis topographique [Termes IGN] oculométrie [Termes IGN] point de repère [Termes IGN] signalisation routière Mots-clés libres : landmark  wayfinding  spatial knowledge  perception  recall  route  nature  geospatial image  3D map  elevation  eye tracking Résumé : (auteur) This dissertation applies the research and methods of spatial cognition in order to contribute to the development of wayfinding support in geospatial applications. The design and development of geospatial applications, such as interactive maps and mobile navigation applications, has been typically founded on the expertise of surveying, cartography and geoinformatics. This has often led to relatively complex expert tools that many users find difficult to use. The research of spatial cognition can provide elementary understanding about human thinking in the use situations of these applications and supplement the knowledge gained using the usability research. Perception of landmarks along routes in nature was studied in season and time-of-day studies with participants who walked nature trails in summer, winter, day and night while thinking aloud about the surroundings. The recall of the route was measured afterwards using sketch-map drawing and photo recognition tasks. The think-aloud protocols were analysed using classification of propositions and natural language processing. The importance of landmarks for the human route perception in nature was confirmed. “Structures”, “Passages” and “Waters” were the most perceived landmark groups. Season and time-of-day significantly affected landmark perception and, based on the results, the adaptivity of geospatial applications in the studied conditions can be improved. The transfer of the empirically acquired knowledge of the landmark perception to geoinformatics was illustrated with a formal landmark ontology for hiking in nature. The measures of landmark recall were found unexpectedly similar in all the studied conditions. The similarity was explained by the salience of landmarks in nature and the structure of route-like sketch maps but also by the participants’ conceptions on what should be drawn on maps. “Passages” and “Structures” were the most-often drawn landmark groups on the sketch maps. Support of geospatial images for wayfinding was evaluated using a literaturebased evaluation framework. Visualisation of elevation was experimented with by rendering a 3D map, a derivative of which was compared to 2D elevation visualisations in an eye-tracking study. Vertical elements and elevation were found to be central wayfinding elements in geo-images and the aerial oblique vantage point the most effective image parameter for transferring spatial knowledge. The rendered 3D map was evaluated as cognitively demanding to look at but, however, showed potential in representing the terrain relief. The dissertation also considers challenges in the application of the methods of spatial cognition research and identifies directions for future studies. Note de contenu : 1. Introduction 2. Literature review 3. Methods 4. Results 5. Discussion and conclusions Numéro de notice : 14878 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : PhD thesis : Science in Technology : Aalto University School of Engineering : 2014 En ligne : https://aaltodoc.aalto.fi/handle/123456789/14049 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=75988

Feasibility of terrestrial laser scanning for plotwise forest inventories / Xinlian Liang (2013)  

Public Titre : Feasibility of terrestrial laser scanning for plotwise forest inventories Type de document : Thèse/HDR Auteurs : Xinlian Liang, Auteur ; Henrik Haggren, Directeur de thèse Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 2013 Collection : Publications of the Finnish Geodetic Institute, ISSN 0085-6932 num. 149 Importance : 150 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-711-299-4 Note générale : bibliographie, ISBN du pdf Department of Real Estate, Planning and Geoinformatics, Aalto University Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] biomasse aérienne [Termes IGN] détection de changement [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Finlande [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] semis de points [Termes IGN] volume en bois Résumé : (auteur) Detailed, up-to-date forest information is increasingly important in quantitative forest inventories. The accuracy of the information retrieval is highly dependent on the quality and quantity of the reference data collected on field sample plots. In practice, the plotwise forest data are used as a reference for the calibration of large-area inventory data measured by aerial and space-borne remote sensing techniques. Field reference data are conventionally collected at the sample plot level by manual measurements. Because of the high costs and labor intensity of manual measurements, the number of tree attributes collected is limited. Some of the most important tree attributes are not even measured or sampled. Terrestrial laser scanning (TLS) has been recently shown to be a promising technique for forest-related studies. Many tree attributes have been correlated with measurements from TLS data. Numerous TLS methods have been proposed. 6However, the feasibility of applying TLS in plotwise forest inventories is still unclear. The major missing factor is automation of data processing. Other factors hampering the acceptance of the technology include the relatively high cost of the TLS instrument, the low measurement accuracy achieved using the automated data processing currently available, and the shortage of experimental results related to the retrieval of advanced stem attributes (e.g., stem curve) and to different forest conditions. In this study, a series of methods to map sample plots were developed, and their applicability in plotwise forest inventories was analyzed. The accuracy of stem mapping, the efficiency of data collection, and the limitations of the techniques were discussed. The results indicate that TLS is capable of documenting a forest sample plot in detail and that automated mapping methods yield accurate measurements of the most important tree attributes, such as diameter at breast height and stem curve. The fully-automated TLS data processing that was developed in this study resulted in measurement accuracy similar to that of manual measurements using conventional tools or models and of manual measurements from point cloud data. The results of this study support the feasibility of TLS for practical forest field inventories. Further research is needed to explore new protocols for the application of TLS in field inventories. Three possible new directions are the integration of detailed tree attributes (e.g., stem curve, volume, and biomass) in large-area inventories, the utilization of TLS field plots in national forest inventories, and the mapping of large sample plots, e.g., in operational harvest planning. More studies need to be performed on sample plots under different forest conditions (development class, tree species, and amount of ground vegetation). Numéro de notice : 26025 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Thèse étrangère En ligne : https://aaltodoc.aalto.fi/bitstream/handle/123456789/11355/isbn9789517112994.pdf [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93651

Object-based interpretation methods for mapping built-up areas / Leena Matikainen (2012) 

Public Titre : Object-based interpretation methods for mapping built-up areas Type de document : Thèse/HDR Auteurs : Leena Matikainen, Auteur Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 2012 Collection : Publications of the Finnish Geodetic Institute, ISSN 0085-6932 num. 147 Importance : 83 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-711-293-2 Note générale : Bibliographie Doctoral dissertation for the degree of Doctor of Science in Technology Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse d'image orientée objet [Termes IGN] bâtiment [Termes IGN] détection de changement [Termes IGN] détection du bâti [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] image aérienne [Termes IGN] image radar moirée [Termes IGN] impulsion laser [Termes IGN] occupation du sol [Termes IGN] segmentation d'image [Termes IGN] zone urbaine Index. décimale : 30.60 Géodésie spatiale Résumé : (Auteur) There is a growing demand for high-quality spatial data and for efficient methods of updating spatial databases. In the present study, automated object-based interpretation methods were developed and tested for coarse land use mapping, detailed land cover and building mapping, and change detection of buildings. Various modern remotely sensed datasets were used in the study. An automatic classification tree method was applied to building detection and land cover classification to automate the development of classification rules. A combination of a permanent land cover classification test field and the classification tree method was suggested and tested to allow rapid analysis and comparison of new datasets. The classification and change detection results were compared with up-to-date map data or reference points to evaluate their quality. The combined use of airborne laser scanner data and digital aerial imagery gave promising results considering topographic mapping. In automated building detection using laser scanner and aerial image data, 96% of all buildings larger than 60 m2 were correctly detected. This accuracy level (96%) is compatible with operational quality requirements. In automated change detection, about 80% of all reference buildings were correctly classified. The overall accuracy of a land cover classification into buildings, trees, vegetated ground and non-vegetated ground using laser scanner and aerial image data was 97% compared with reference points. When aerial image data alone were used, the accuracy was 74%. A comparison between first pulse and last pulse laser scanner data in building detection was also carried out. The comparison showed that the use of last pulse data instead of first pulse data can improve the building detection results. The results yielded by automated interpretation methods could be helpful in the manual updating process of a topographic database. The results could also be used as the basis for further automated processing steps to delineate and reconstruct objects. The synthetic aperture radar (SAR) and optical satellite image data used in the study have their main potential in land cover monitoring applications. The coarse land use classification of a multitemporal interferometric SAR dataset into built-up areas, forests and open areas lead to an overall accuracy of 97% when compared with reference points. This dataset also appeared to be promising for classifying built-up areas into subclasses according to building density. Important topics for further research include more advanced interpretation methods, new and multitemporal datasets, optimal combinations of the datasets, and wider sets of objects and classes. From the practical point of view, work is needed in fitting automated interpretation methods in operational mapping processes and in further testing of the methods. Note de contenu : 1. INTRODUCTION 1.1 Background and motivation 1.2 Hypothesis 1.3 Objectives of the study 1.4 Structure and contribution of the study 2. LITERATURE REVIEW 2.1 General 2.2 Object-based image analysis 2.3 Classification trees 2.4 Mapping built-up areas using coherence and intensity from interferometric SAR images 2.5 Mapping buildings and land cover using laser scanner and aerial image data 2.5.1 Building detection 2.5.2 Land cover classification 2.6 Change detection of buildings using laser scanner and aerial image data 3. MATERIALS AND METHODS 3.1 Study areas and materials 3.2 Methods 3.2.1 Method development for mapping built-up areas 3.2.2 Quality evaluation 4. RESULTS 4.1 Mapping built-up areas using a multitemporal interferometric SAR dataset 4.1.1 Land use classification 4.1.2 Further analysis of built-up areas 4.2 Building detection using laser scanner and aerial image data 4.3 Change detection of buildings 4.4 Land cover mapping using classification trees, test field points, and various input datasets 5. DISCUSSION 5.1 Methods developed for mapping built-up areas 5.2 Quality of the results 5.3 Feasibility of the methods for practical mapping applications 5.4 Other studies and developments 5.5 Further research 6. SUMMARY AND CONCLUSIONS Numéro de notice : 14649 Affiliation des auteurs : non IGN Autre URL associée : URL page Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : Doctoral thesis : Technology : Aalto University : 2012 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62677

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Documents numériques

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Tree species classification with multiple source remote sensing data / Eetu Puttonen (2012)  

Public Titre : Tree species classification with multiple source remote sensing data Type de document : Thèse/HDR Auteurs : Eetu Puttonen, Auteur ; Juha Hyyppä, Directeur de thèse Editeur : Helsinki : Finnish Geodetic Institute FGI Année de publication : 2012 Collection : Publications of the Finnish Geodetic Institute, ISSN 0085-6932 num. 145 Importance : 86 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-951-711-289-5 Note générale : Doctoral dissertation University of Helsinki, Faculty of Science, Department of Physics, geophysics and astronomy Finnish Geodetic Institute, Department of Photogrammetry and Remote Sensing ISBN du pdf Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse discriminante [Termes IGN] arbre (flore) [Termes IGN] capteur hyperspectral [Termes IGN] classification [Termes IGN] classification par séparateurs à vaste marge [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] espèce végétale [Termes IGN] fusion de données [Termes IGN] image spectrale [Termes IGN] semis de points Résumé : (auteur) Remote sensing is a study that provides information on targets of interest without direct interaction with them. Generally, the term is used for measurement techniques that detect electro-magnetic radiation emitted or reflected from the targets. Commonly used wavelength ranges include visible, infra-red, microwaves, and thermal bands. This information can be exploited to determine the structural and spectral properties of targets. Remote sensing techniques are typically utilized in mapping solutions, environment monitoring, target recognition, change detection, and in creation of physical models. In Finland, remote sensing research is of specific importance in forest sciences and industry as they need precise information on tree quantity and quality over large forest ranges. Tree species information on individual tree level is an important parameter to achieve this goal. The aim of this thesis is to study how individual tree species information can be extracted with multiple source remote sensing data. The aim is achieved by combining spatial and spectral remote sensing data. Structural properties of individual trees are determined from three dimensional point clouds collected with laser scanners. Spectral properties of trees are collected with cameras or spectrometers. The thesis consists of four separate studies. The first study examined how shading information of trees canopies could be exploited to improve tree species classification in data collected with airborne sensors. The second study examined the classification performance of a low-cost, multi-sensor, mobile mapping system. The third study investigated the classification performance and accuracy of a novel, active hyperspectral laser scanner. Finally, the fourth study evaluated the suitability of artificial surfaces as on-site intensity calibration targets. The results of the three classification studies showed that the use of combined point cloud and spectral information yielded the best classification results in all study cases when compared against classification results obtained with only structural or spectral information. Moreover, the studies showed that the improved results could be achieved with a low total number of mixed structural and spectral classification parameters. The fourth study showed that the artificial surfaces work as calibration surfaces only in limited cases. The main outcome of the thesis was that the active remote sensing systems measuring multiple wavelengths simultaneously should be promoted. They have a significant potential to improve tree species classification performance even with a few application-specific wavelengths. Numéro de notice : 15863 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Thèse étrangère Note de thèse : Doctoral dissertation : Photogrammetry and Remote Sensing : University of Helsinki : 2012 En ligne : http://hdl.handle.net/10138/33956 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93650

The EuroSDR project "radiometric aspects of digital photogrammetric images" : results of the empirical phase / Eija Honkavaara (01/06/2011)  

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Interference measurements of the Nummela standard baseline in 2005 and 2007 / Jorma Jokela (2010)    

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Preventing interruptions in mobile map reading process by personnalisation / Annu-Maaria Nivala (2004)    

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Mean monthly series of sea level observations (1777-1993) at the Kronstadt gauge / V. Bogdanov (2000)

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Final results of the Baltic Sea level 1997 GPS campaign / Markku Poutanen (1999)

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Kyviskes calibration baseline / Jorma Jokela (1999)

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Map generalisation in the nordic countries / T. Kilpelainen (1999)

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Orientation of optical airborne and spaceborne images for small and medium scale mapping purposes / Eija Honkavaara (1999)

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Quality of FLPIS land parcel digitization / Harri Kaartinen (1999)

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Quality of FLPIS orthophotos / Eija Honkavaara (1999)

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