The need for custom footwear among the consumers is growing every day. Serious research is being undertaken with regards to the fit and comfort of the footwear. The integration of scanning systems in the footwear and orthotic industries have played a significant role in generating 3D digital representation of the foot for automated measurements from which a custom footwear or an orthosis is manufactured. The cost of such systems is considerably high for many manufacturers due to their expensive components, complex processing algorithms and difficult calibration techniques. This thesis presents a fast and robust calibration technique for a low-cost 3D laser scanner. The calibration technique is based on determining the mathematical relationship that relates the image coordinates to the real world coordinates. The relationship is determined by mapping the known real world coordinates of a reference object to its corresponding image coordinates by multivariate polynomial regression. With the developed mathematical relationship, 3D data points can be obtained from the 2D images of any object placed in the scanner. An image processing script is developed to detect the 2D image points of the laser profile in a series of scan images from 8 cameras. The detected 2D image points are reconstructed into 3D data points based on the mathematical model developed by the calibration process. Following that, the output model is achieved by triangulating the 3D data points as a mesh model with vertices and normals. The data is exported as a computer aided design (CAD) software readable format for viewing and measuring. This method proves to be less complex and the scanner was able to generate 3D models with an accuracy of +/-0.05 cm. The 3D data points from the output model were compared against a reference model scanned by an industrial grade scanner to verify and validate the result. The devised methodology for calibrating the 3D laser scanner can be employed to obtain accurate and reliable 3D data of the foot shape and it has been successfully tested with several participants.

The need for custom footwear among the consumers is growing every day. Serious research is being undertaken with regards to the fit and comfort of the footwear. The integration of scanning systems in the footwear and orthotic industries have played a significant role in generating 3D digital representation of the foot for automated measurements from which a custom footwear or an orthosis is manufactured. The cost of such systems is considerably high for many manufacturers due to their expensive components, complex processing algorithms and difficult calibration techniques. This thesis presents a fast and robust calibration technique for a low-cost 3D laser scanner. The calibration technique is based on determining the mathematical relationship that relates the image coordinates to the real world coordinates. The relationship is determined by mapping the known real world coordinates of a reference object to its corresponding image coordinates by multivariate polynomial regression. With the developed mathematical relationship, 3D data points can be obtained from the 2D images of any object placed in the scanner. An image processing script is developed to detect the 2D image points of the laser profile in a series of scan images from 8 cameras. The detected 2D image points are reconstructed into 3D data points based on the mathematical model developed by the calibration process. Following that, the output model is achieved by triangulating the 3D data points as a mesh model with vertices and normals. The data is exported as a computer aided design (CAD) software readable format for viewing and measuring. This method proves to be less complex and the scanner was able to generate 3D models with an accuracy of +/-0.05 cm. The 3D data points from the output model were compared against a reference model scanned by an industrial grade scanner to verify and validate the result. The devised methodology for calibrating the 3D laser scanner can be employed to obtain accurate and reliable 3D data of the foot shape and it has been successfully tested with several participants.

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-05T15:17:55Z No. of bitstreams: 2 DISSERTAÇÃO Mirele Viegas da Silva.pdf: 7784954 bytes, checksum: 56193e4339b0daaaa3548129ff171819 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-05T15:17:55Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Mirele Viegas da Silva.pdf: 7784954 bytes, checksum: 56193e4339b0daaaa3548129ff171819 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-06-04 / O laser scanner aerotransportado, ALS (Airborne Laser Scanner), também conhecido como LIDAR (Light Detection and Ranging), consiste atualmente numa das tecnologias mais utilizadas para a aquisição de enormes volumes de dados num curto período de tempo. Essa tecnologia envolve a emissão de um pulso eletromagnético em direção à superfície tendo como produto as coordenadas plani-altimétricas e a intensidade do feixe refletido pelo objeto atingido. A posição tridimensional somente pode ser calculada, se em qualquer momento, a posição e orientação do sistema de laser se façam conhecidos com respeito a um sistema de coordenadas, isso é possível devido ao fato que o sistema dispõe de GPS (Global Positioning System)/GNSS (Global Navigation Satellite System) e INS (Inertial Navigation System), auxiliando diretamente no georreferenciamento das imagens e nuvens de pontos adquiridas. O conjunto de dados do laser scanner é uma alternativa poderosa para ser aplicado na otimização de técnicas de mapeamento fotogramétrico, permitindo um ótimo desempenho para extrair informação espacial tridimensional. A imagem fotogramétrica permite, por sua vez, a extração exata de feições planimétricas. Este trabalho descreve uma metodologia para avaliar feições planimétricas em áreas urbanas obtidas com a tecnologia laser scanner aerotransportado tendo, como objetivo, estudar a qualidade posicional planimétrica das feições pontuais em imagens provenientes do laser scanner (imagens de intensidade), através da comparação da saída de dados deste com os dados provenientes do método fotogramétrico aéreo e topográfico. Na presente pesquisa, foi concentrada a detecção principalmente de feições planimétricas de telhados e arruamentos. O método de avaliação da acurácia foi baseado na análise de pontos e medidas de feições lineares obtidas com imagens de intensidade do sistema laser scanner comparadas com medidas obtidas em levantamento GNSS e restituição fotogramétrica de duas áreas localizada no Campus da Universidade Federal de Pernambuco e no bairro da Macaxeira, município de Recife/PE, avaliando de acordo com o Padrão de Exatidão Cartográfico para Produtos Cartográficos Digitais – PEC PCD.

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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.

Laser scanners provide a three-dimensional sampled representation of the surfaces of objects. The spatial resolution of the data is much higher than that of conventional surveying methods. The data collected from different locations of a laser scanner must be transformed into a common coordinate system. If good a priori alignment is provided and the point clouds share a large overlapping region, existing registration methods, such as the Iterative Closest Point (ICP) or Chen and Medioni’s method, work well. In practical applications of laser scanners, partially overlapping and unorganised point clouds are provided without good initial alignment. In these cases, the existing registration methods are not appropriate since it becomes very difficult to find the correspondence of the point clouds. A registration method, the Geometric Primitive ICP with the RANSAC (GPICPR), using geometric primitives, neighbourhood search, the positional uncertainty of laser scanners, and an outlier removal procedure is proposed in this thesis. The change of geometric curvature and approximate normal vector of the surface formed by a point and its neighbourhood are used for selecting the possible correspondences of point clouds. In addition, an explicit expression of the position uncertainty of measurement by laser scanners is presented in this dissertation and this position uncertainty is utilised to estimate the precision and accuracy of the estimated relative transformation parameters between point clouds. The GP-ICPR was tested with both simulated data and datasets from close range and terrestrial laser scanners in terms of its precision, accuracy, and convergence region. It was shown that the GP-ICPR improved the precision of the estimated relative transformation parameters as much as a factor of 5. / In addition, the rotational convergence region of the GP-ICPR on the order of 10°, which is much larger than the ICP or its variants, provides a window of opportunity to utilise this automated registration method in practical applications such as terrestrial surveying and deformation monitoring.

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.

Automated construction progress tracking is becoming critical to efficient and effective construction management. More and more construction companies are putting aside the old way of tracking progress, which was mainly based on foremen daily reports and visual inspections, and are adopting 3D sensing technologies as a new and modern way of tracking progress. Technologies such as 3D laser scanners (LADARs) are investigated as a means to acquire comprehensive 3D point-cloud data which can then be studied by management to determine the progress of construction. Although being much more accurate and efficient than visual inspections, this new progress tracking approach can be improved by applying object recognition algorithms that enable an automated progress tracking. This new approach has been investigated by other researchers, but only for progress tracking of structural elements. This study focuses on mechanical objects such as pipes and ducts, which would give the progress tracking a better level of detail and a wider scope. The investigation is carried out on a field database acquired during the construction of the Engineering VI Building at the University of Waterloo. It was found that the laser scanning technology is a suitable method for acquiring point-clouds of pipes and ductwork, and also that the object recognition algorithm used in this study allows a progress tracking as well as a quality tracking of the HVAC system installation.

The different between Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) is that ROV is connected with the main computer by the electronic cable, so the operator can control the vehicle depending on the environment showing on the monitor; However, AUV is dependent on the received data to autonomously respond the condition via controlling program. In our research, we wanted to use the General Purpose Controller, which had been developed in the previous experiment, in the mission-mode to construct our AUV system for remaining the original ROV controlling system and switching mode between AUV system and ROV system. The mission was divided into primary and secondary mission written by the txt file which is known as mission script, including execute time, target, and mission type etc. In addition, we used the Watch Dog Timer (WDT) in our AUV for the security procedure. When the mission is failed or over the setting time, the AUV will change to the security mode and go forward to the water surface. The other topic in this research wanted to use the Seafloor Laser Scanner (SLS), which was mounted on the AUV, to improve the scanning efficiency. However, when the scanner was working, the AUV had to maintain the stable altitude to the sea floor, so the accurately output power of thruster is needed to be considered and tested. In this part, we found out the properly controlling way in the small water tank first, and then checked the attitude and scanning system in the swimmer pool and towing tank in NCKU respectively, to prove the ability of SLS of AUV system.

This work reports the system integration of the underwater seafloor laser scanner, designed and fabricated by Institute of Undersea Technology, National Sun Yat-sen University, with the in situ porosity measurement system, known as IMP2, developed by Applied Physics Lab, University of Washington. Our original prototype underwater seafloor laser scanner worked more like an indoor experimental setup rather than an instrument. It is the goal of this work to modify the detail design of hardware and software of the system such that the operation of the scanner and the data analysis of the results can be done like a commercial instrument. Our laser scanning module adopts structural light method with a single camera approach. The calibration of the camera is achieved with a template board on which sets of grid points are laid with numerical control milling machine. These grid points are used to create longitudinal and latitudinal lines for pixel-to-coordinate conversion. Three sub-pixel sampling methods, namely, intensity weighted centroid, second order polynomial intensity fitting and Gaussian intensity fitting, are developed to locate the center of the laser light strip on pixel plane and to be converted into engineering coordinates. For the convenience of post-processing, grid point meshing and spectrum analysis packages are built-in to provide standard output for further studies. The overall performance of the system was validated by four tests in indoor tanks and field as well. One scanning in air was undertaken to verify if synchronization signal between the laser scanner and the motion of the linear track was correct; several models of known dimension were placed in the water tank for scanning to see if the system reaches the desired accuracy; an integration of the laser scanner and the IMP2 was tested prior to the deployment in the sea, and a scanning a artificial seafloor model of known spatial spectra indicated the proper functioning of the combined system; finally a successful 20-meter deep field deployment and retrieve assured the bases for the acquisition of seafloor roughness field for acoustics related research.