Novas tecnologias estão sendo desenvolvidas constantemente para coletar informações de superfícies ou de sólidos para diversas finalidades. Alguns métodos clássicos, como a Topografia e a Fotogrametria terrestre, com o passar dos anos, tiveram uma grande evolução. Na Fotogrametria terrestre todo o processo está sendo feito em meio digital. Na topografia, as estações totais automatizaram a medição de ângulos e distâncias. Essa evolução tecnológica fez com que os levantamentos se tornassem cada vez mais rápidos e precisos, aumentando a produtividade. O mais recente nessa evolução é o levantamento através do sistema de varredura a laser (Laser Scanner) 3D. São muitas as aplicações dessa tecnologia, dentre as quais pode-se citar: túneis, levantamento do como construído (as-built), mineração (principalmente subterrânea), arqueologia, levantamento de monumentos para restauração, refinarias e instalações industriais e outras, caracterizadas pela grande complexidade dos elementos envolvidos. A presente dissertação apresenta os conceitos envolvidos em todos os processos, desde a coleta de dados até o produto final. Desenvolve uma metodologia de uso que possa ser útil em diversas áreas, mostra uma aplicação completa na área de túneis, complementada por uma visão geral da área de plantas industriais e procura apresentar testes para quantificar a precisão que se obtém por essa tecnologia. / New technologies are constantly being developed in order to collect information of surfaces or solids for diverse purposes. Some classic methods such as topography and terrestrial photogrammetry have had a great evolution in the past. For example, all the processes of the terrestrial photogrammetry are made in digital way and the Total Stations have automated the measurements of angles and distances. This technical evolution made the surveying faster and accurate, increasing the productivity. However this evolution does not stop for there; in other words, the last technology in the area of topography is the surveying with the system known as Laser Scanner 3D. The Laser Scanner technology 3D has a lot of applications such as: tunnel, as-built, mining (mainly in the underground); archaeology (for restore monuments), refineries, industrial installations, etc., characterized by the great complexity of the involved elements. This work presents concepts involved in all the processes, since from data collection to the final product. It develops a methodology of use that can be applied in several areas, with emphasis in tunnels surveying area and presents some tests to quantization the accuracy.

This report evaluates possibilities to combine volumetric ultrasound (us) data together with the recent work published on advanced skin rendering techniques. We focus mainly on how to filter us data and localize surfaces within us data. We also evaluate recent skin rendering techniques in order to have a good understanding of what is needed from the us for rendering realistic skin. us data is acquired using sonography and have a low signal-to-noise ratio by nature, this makes it harder to extract surfaces compared to other medical data acquisition methods such as ct and mr. This report present an algorithm which implements a variational classification technique to emphasize surfaces within us and using a rbf network to fit an implicit function to these surfaces. Using this approach presented we have successfully extract smooth meshes from the noisy us data.

Avec l'évolution des dispositifs d'acquisition 3D, les nuages de points sont maintenant devenus une représentation essentielle des scènes numérisées. Les systèmes récents sont capables de capturer plusieurs centaines de millions de points en une seule acquisition. Comme plusieurs acquisitions sont nécessaires pour capturer la géométrie de scènes de grande taille, un site historique par exemple, nous obtenons des nuages de points massifs, i.e., composés de plusieurs milliards de points. Dans cette thèse, nous nous intéressons à la structuration et à la manipulation de nuages de points issus d'acquisitions générées à partir de LiDARs terrestres. A partir de la structure de chaque acquisition, des graphes, représentant chacun la connectivité locale de la surface numérisée, sont construits. Les graphes créés sont ensuite liés entre eux afin d'obtenir une représentation globale de la surface capturée. Nous montrons que cette structure est particulièrement adaptée à la manipulation de la surface sous-jacente aux nuages de points massifs, même sur des ordinateurs ayant une mémoire limitée. Notamment, nous montrons que cette structure permet de traiter deux problèmes spécifiques à ce type de données. Un premier lié au ré-échantillonnage de nuages de points, en générant des distributions de bonne qualité en termes de bruit bleu grâce à un algorithme d'échantillonnage en disques de Poisson. Un autre lié à la construction de diagrammes de Voronoï centroïdaux, permettant l'amélioration de la qualité des distributions générées, ainsi que la reconstruction de maillages triangulaires. / With the evolution of 3D acquisition devices, point clouds have now become an essential representation of digitized scenes. Recent systems are able to capture several hundreds of millions of points in a single acquisition. As multiple acquisitions are necessary to capture the geometry of large-scale scenes, a historical site for example, we obtain massive point clouds, i.e., composed of billions of points. In this thesis, we are interested in the structuration and manipulation of point clouds from acquisitions generated by terrestrial LiDARs. From the structure of each acquisition, graphs, each representing the local connectivity of the digitized surface, are constructed. Created graphs are then linked together to obtain a global representation of the captured surface. We show that this structure is particularly adapted to the manipulation of the underlying surface of massive point clouds, even on computers with limited memory. Especially, we show that this structure allow to deal with two problems specific to that kind of data. A first one linked to the resampling of point clouds, by generating distributions of good quality in terms of blue noise thanks to a Poisson disk sampling algorithm. Another one connected to the construction of centroidal Voronoi tessellations, allowing to enhance the quality of generated distributions and to reconstruct triangular meshes.

The spatial accuracy of points obtained from aerial laser scanning is most affected by the parameters of the GNSS receiver used, the IMU unit and the parameters of the flight itself. An important role is played by the accuracy of the so-called calibration, ie the determination of the transformation elements between the coordinate systems of the scanning unit itself, the IMU and the position of the phase center of the GNSS antenna. The diploma thesis deals with the calibration accuracy of the IMU / GNSS unit. It compares the displacements and rotations of a point cloud acquired by LiDAR (laser scanner RIEGL miniVUX-1UAV) in relation to the calibration elements given by the manufacturer. Evaluate the results using calculated standard deviations and positional differences in the raw point cloud, or by comparing point clouds obtained by another method. It also focuses on verifying geometric accuracy using checkpoints. The accuracy of the IMU / GNSS calibration is minimal after verifying the results and comparing the influence of the calibration elements given by the manufacturer. There was no significant improvement in the quality of the point cloud. At the same time, it was found that for better quality of the scanned data, it is necessary to perform cross-flights when UAV scanning. Key words UAV,...

Topographic mapping of rock formations using GIS methods Abstract This thesis deals with issues of creating 3D models of rock formations with data from terrestrial laser scanning, close range photogrammetry and UAV photogrammetry. The theoretical part focuses on explaining functioning and usage of those methods. Beside that there is described issues of 3D point cloud filtering. Practical part of this work describes data collecting and processing procedure. Further there is proposed filtering process which aim to remove noise points from point clouds and remove vegetation with combination of vegetation index ExG, clustering algorithm DBSCAN and Hough Transform. The proposed method is tested on the selected rock formation in Bohemian Switzerland National Park. The evaluation of the proposed method is based on comparison of models filtered with proposed method with reference models, which are filtered manually. Finally, the achieved accuracy of the models is evaluated using geodetic measurements. key words laser scanning, photogrammetry, UAV, point cloud, data filtering

In this thesis, various software for point cloud visualization has been investigated. Laser scanning is widely used to create three-dimensional models, but there is a lack of software for visualization. Point clouds usually have a large file size and need convenient methods for visualization and presentation to third parties. The development of browsers means that there are good opportunities today to visualize point clouds on web-based services. The purpose has been to investigate professional software with open source and free software in how they manage to visualize, measure and present point clouds. Details in point clouds is controlled by its point density. Higher point density will result in better details but will take longer time to scan and requires more storage space. The density of the point cloud is controlled by the requirement from the client. It is not certain that a high point density is necessary to strive for considering it will result in more data to handle. The software that has been investigated is Autodesk ReCap, Leica Truview, Pointscene and Potree, and they have all been compared to Leica Cyclone. Only three of them have been able to read the PTS-file format, while Potree and Truview have received the point cloud converted and exported to their proprietary file formats. The comparison between the softwares was mainly based on differences in length measurements, as angle and area-specific tools are not available in all softwares. The length measurements were repeated 30 times and it is the average and the uncertainty for each software that has been used in the comparison. The survey shows that there are small differences between the software except for Truview, which is the only software with significant deviations from Cyclone. There is not any significant differences in length measurements that arise when there have been conversions to Potree. Pointscene and Potree have visual similarities, Pointscene is however the preferred software because its own servers available which simplifies sharing point clouds to other users.

This diploma thesis deals with the processing of point clouds captured by the Kinect sensor from single position. As part of this thesis an application was designed, which is able to register and reconstruct surface using selected methods. The registration of overlapping frames is based on computation of key points and their FPFH histograms from which the estimation of correspondence is computed. This estimation is then refined and redundant point filtering is performed. Surface is reconstructed from the registered and modified point cloud using Greedy Projection Triangulation. All computations are performed offline. The output of this application is textured polygonial model and an image for texture creation. With assumption of correctly set parameters the results are in a good quality for creation of virtual tours and visualization.

The aim of this thesis is the measure of the Rokštejn castle by laser scanning. The measured data are processed in the SCENE software and accuracy of registration and transformation of scans is intended. The next step is to test the software for working with point cloud. In the end, is in the selected 3D software created 3D model of the castle by using processed point cloud.

The aim of the diploma thesis is to create a 3D model of the given object using laser scanning technology. Subsequent adjustments of the model and its separate preparation for possible 3D printing will be done through appropriate programs. The next 3D model of the identical object will be made based on the created photos and will be edited and prepared in the same way for possible 3D printing.

This thesis presents various approaches for race track surface reconstruction based on different algorithms designated for these purposes. In addition to surface reconstruction it also offers proposals for polygon mesh filling in the unscanned areas around the track.