This thesis reports investigations into laser ablation inductively coupled plasma emission spectrometry for rapid elemental analysis of a diverse range of samples: glasses, aqueous solutions, oils, coated steels and glasses, and biological samples. Bulk analysis of glasses for major, minor and trace elements is reported. Results showed that element emission responses are dependent upon laser operating conditions. With optimised operating conditions of a Q switched laser operating at 60 J for 5 s ablation time with the laser defocused by 5 mm above the sample surface. The limits of detection are in the sub ug g -1 level with precision ranging from 6.6 %RSD for a non volatile element such as boron to 23 %RSD for a volatile element silver. Although the principal aim of using aqueous multielement solutions as novel calibration standards for quantitative analysis of other liquids was not achieved, optimised laser operating parameters needed for microsampling of aqueous solutions and analytical performance data were obtained. The optimum laser operating conditions for a 20 ul sample were found to be the same as for glasses and were as follows: a Q switched laser operating at 60 J for a 5 s ablation time with the laser defocused by 5 mm above the sample surface. Transport efficiencies of approximately 30 % can be achieved, compared to < 1% by pneumatic nebulisation. Also there was no differential loss of elements by laser ablation which may occur with electrothermal vaporisation. Limits of detection were found to be in the sub ug ml -1 level. Precisions were typically between 6.6 and 12 %RSD. The main cause for lack of precision was spattering of the sample. Microsampling of oils by laser ablation proved to be an effective and accurate technique for rapid determination of element concentration without the need for sample filtration or digestion. Precision proved to be better than for aqueous solutions, typically from 3 to 7 %RSD, because of a reduction in spattering. The same optimum laser operating conditions used for aqueous solutions were identical for oils. This thesis reports the first experiments to fully utilise laser ablation as a routine method for quantitative measurement of coating depth for coated steels and glasses. It was found that the peak width at half the maximum height was proportional to the coating thickness (over a range of 1 to 10 um). With optimised laser operating conditions a depth resolution of less than 1 um was achieved. The optimum laser operating conditions were as follows: a Q switched laser ran continuously with a laser lamp energy of 60 J at 10 Hz pulse repetition rate. Finally experiments show the great potential for the use of laser ablation as a microsampling technique for microtome tissue samples. Micro depth analysis of nickel distribution in skin shows that the technique could differentiate between two skin samples with different nickel concentrations. The use of gel multielement standards as a novel calibration technique for analysis of microtome tissue samples has also been demonstrated. Optimum laser operating condition were to use a moderate laser energy of 750 V with the laser defocused 5 mm above the sample surface.

Concrete is the most widely used construction material in the world, so the assessment of damage in concrete is critical from the point of view of both safety and cost. Of particular interest are macro cracks that extend through the concrete cover of the reinforcement, which can potentially expose the reinforcement to corrosive elements. The high density of scatterers such as aggregate and voids in concrete makes quantitative imaging with coherent ultrasound difficult. As an alternative, this research focuses on diffuse energy based ultrasonic methods rather than coherent ultrasonic methods for crack depth assessment. Two types of ultrasonic measurements were made on real cracks formed under four point bending: one that focuses on time of flight measurements from an impactor; while the other uses the arrival time of maximum energy in a diffuse field excited by an impulsive load from a transducer. Each of these ultrasonic techniques is used to interrogate a macro crack in a concrete beam, and the results are compared to determine their accuracy and robustness. The actual crack depth is determined using direct surface measurements and a destructive dye-injected approach with drilled cores. The results suggest that the diffusion method, using a maximum energy approach, more accurately estimates the crack than visual inspection and impact echo methods, which overestimate the depth.

<p>An investigation was initiated, targeting snapshot 3D image sensors, with the objective to match the speed and resolution of a scanning sheet-of-light system, without using a scanning motion. The goal was a system capable of acquiring 25 snapshot images per second from a quadratic scene with a side from 50 mm to 1000 mm, sampled in 512×512 height measurement points, and with a depth resolution of 1 µm and beyond. </p><p>A wide search of information about existing 3D measurement techniques resulted in a list of possible schemes, each presented with its advantages and disadvantages. No single scheme proved successful in meeting all the requirements. Pulse modulated time-of-flight is the only scheme capable of depth imaging by using only one exposure. However, a resolution of 1 µm corresponds to a pulse edge detection accuracy of 6.67 fs when visible light or other electromagnetic waves are used. Sequentially coded light projections require a logarithmic number of exposures. By projecting several patterns at the same time, using for instance light of different colours, the required number of exposures is reduced even further. The patterns are, however, not as well focused as a laser sheet-of-light can be. </p><p>Using powerful architectural concepts such as matrix array picture processing (MAPP) and near-sensor image processing (NSIP) a sensor proposal was presented, designed to give as much support as possible to a large number of 3D imaging schemes. It allows for delayed decisions about details in the future implementation. </p><p>It is necessary to relax at leastone of the demands for this project in order to realise a working 3D imaging scheme using concurrent technology. One of the candidates for relaxation is the most obvious demand of snapshot behaviour. Furthermore, there are a number of decisions to make before designing an actual system using the recommendations presented in this thesis. The ongoing development of electronics, optics, and imaging schemes might be able to meet the 3D snapshot demands in a near future. The details of light sensing electronics must be carefully evaluated and the optical components such as lenses, projectors, and fibres should be studied in detail.</p>

An investigation was initiated, targeting snapshot 3D image sensors, with the objective to match the speed and resolution of a scanning sheet-of-light system, without using a scanning motion. The goal was a system capable of acquiring 25 snapshot images per second from a quadratic scene with a side from 50 mm to 1000 mm, sampled in 512×512 height measurement points, and with a depth resolution of 1 µm and beyond. A wide search of information about existing 3D measurement techniques resulted in a list of possible schemes, each presented with its advantages and disadvantages. No single scheme proved successful in meeting all the requirements. Pulse modulated time-of-flight is the only scheme capable of depth imaging by using only one exposure. However, a resolution of 1 µm corresponds to a pulse edge detection accuracy of 6.67 fs when visible light or other electromagnetic waves are used. Sequentially coded light projections require a logarithmic number of exposures. By projecting several patterns at the same time, using for instance light of different colours, the required number of exposures is reduced even further. The patterns are, however, not as well focused as a laser sheet-of-light can be. Using powerful architectural concepts such as matrix array picture processing (MAPP) and near-sensor image processing (NSIP) a sensor proposal was presented, designed to give as much support as possible to a large number of 3D imaging schemes. It allows for delayed decisions about details in the future implementation. It is necessary to relax at leastone of the demands for this project in order to realise a working 3D imaging scheme using concurrent technology. One of the candidates for relaxation is the most obvious demand of snapshot behaviour. Furthermore, there are a number of decisions to make before designing an actual system using the recommendations presented in this thesis. The ongoing development of electronics, optics, and imaging schemes might be able to meet the 3D snapshot demands in a near future. The details of light sensing electronics must be carefully evaluated and the optical components such as lenses, projectors, and fibres should be studied in detail.

In our society with its aging population, the design and implementation of a highperformance distributed multi-sensor and information system for autonomous physical services become more and more important. In line with this, this thesis proposes an Intelligent Multi-Sensor System, IMSS, that surveys a human activities space to detect and identify a target for a specific service. The subject of this thesis covers three main aspects related to the set-up of an IMSS: an improved depth measurement and reconstruction method and its related uncertainty, a surveillance and tracking algorithm and finally a way to validate and evaluate the proposed methods and algorithms. The thesis discusses how a model of the depth spatial quantisation uncertainty can be implemented to optimize the configuration of a sensor system to capture information of the target objects and their environment with required specifications. The thesis introduces the dithering algorithm which significantly reduces the depth reconstruction uncertainty. Furthermore, the dithering algorithm is implemented on a sensor-shifted stereo camera, thus simplifying depth reconstruction without compromising the common stereo field of view. To track multiple targets continuously, the Gaussian Mixture Probability Hypothesis Density, GM-PHD, algorithm is implemented with the help of vision and Radio Frequency Identification, RFID, technologies. The performance of the tracking algorithm in a vision system is evaluated by a circular motion test signal. The thesis introduces constraints to the target space, the stereo pair characteristics and the depth reconstruction accuracy to optimize the vision system and to control the performance of surveillance and 3D reconstruction through integer linear programming. The human being within the activity space is modelled as a tetrahedron, and a field of view in spherical coordinates are used in the control algorithms. In order to integrate human behaviour and perception into a technical system, the proposed adaptive measurement method makes use of the Fuzzily Defined Variable, FDV. The FDV approach enables an estimation of the quality index based on qualitative and quantitative factors for image quality evaluation using a neural network. The thesis consists of two parts, where Part I gives an overview of the applied theory and research methods used, and Part II comprises the eight papers included in the thesis.

[pt] Esta dissertação tem por objetivo realizar a caracterização metrológica de scanners ópticos tridimensionais por projeção de luz estruturada com vistas à aplicação em ensaios de coletes balísticos. Técnicas de digitalização tridimensional vêm ganhando popularidade nas últimas décadas, entretanto o recente emprego de equipamentos de digitalização 3D em ensaios de coletes balísticos constitui uma nova aplicação para estes equipamentos, em especial na caracterização dos traumas originados pelos impactos de projéteis, o que motivou a realização do estudo. A metodologia empregada fundamentou-se nas pesquisas bibliográfica, documental, experimental e de laboratório que tiveram por objetivo coletar dados utilizando scanner por projeção de luz estruturada no contexto de ensaios de coletes balísticos e compará-los com valores de referência. Foram sugeridos processos de alinhamento, segmentação, filtragem e estabelecimento de planos de referência que se mostraram adequados ao tratamento das nuvens de pontos obtidas nos ensaios de coletes balísticos. Os resultados confirmaram os erros sistemáticos relatados na literatura para equipamentos de digitalização por luz estruturada e possibilitaram uma estimativa da incerteza de medição para o equipamento em questão. Concluiuse que os valores críticos de medição de traumas são corretamente medidos pelo instrumento de digitalização 3D e por meio da utilização do método sugerido para tratamento de nuvens de pontos neste contexto. / [en] This dissertation aims at performing the metrological characterization of three-dimensional optical scanners by structured light projection for application in ballistic vest tests. Three-dimensional scanning techniques have been gaining popularity in recent decades, however the recent use of 3D scanning equipment in ballistic vests testing is a new application for these devices, especially in the characterization of traumas caused by projectile impacts, which motivated the realization of the study. The methodology used was based on bibliographic, documentary, experimental and laboratory research aimed at collecting data using a structured light projection scanner in the context of ballistic vests tests and comparing them with reference values. Procedures for alignment, segmentation, filtering and establishment of reference planes were suggested, which proved to be adequate for the treatment of point clouds obtained from ballistic vest tests. The results confirmed the systematic errors reported in the literature for structured light scanning equipment and made it possible to estimate the measurement uncertainty for the equipment in question. It was concluded that the critical trauma measurement values are correctly measured by the 3D scanning instrument and by using the suggested method for treating point clouds in this context.

In this master thesis, the accuracy of the crack depth meter RMG 4015 was evaluated for different types of cracks with various damage mechanisms. In total, 61 crack depth measurements were conducted with the crack depth meter on 56 cracks which were located in the 23 different test pieces supplied by Kiwa. The measured crack depths were then compared to the true crack depths, which were determined by cutting the test pieces and measuring directly on the cross-sections of the cracks using a light optical microscope. The results of the comparison showed that the RMG 4015, which uses potential drop techniques, was very accurate at measuring both strain induced and alkaline stress corrosion cracks. However, the results also showed that the crack depth meter underestimates chloride induced stress corrosion cracks, corrosion fatigue cracks and stress corrosion cracks/hydrogen embrittlement cracks at varying degrees. Therefore, the main recommendation for Kiwa is to switch the RMG 4015 to a crack depth meter that uses ultrasonic techniques instead. The master thesis also explored the possibilities to improve an FE model produced by Kiwa in a previous project which involved an analysis of a cracked component. The present crack depth measure program included a test piece from this component. The stress distribution in the original model did not represent the cracks found in the real structure and it was suspected to be the result of some boundary conditions not corresponding to those acting in the actual pipe system. Some adjustments to the boundary conditions and contact regions were made and a new improved model with a better representing stress distribution was found. / I detta examensarbete utvärderades noggrannheten hos sprickdjupsmätaren RMG 4015 för olika typer av sprickor med olika skademekanismer. Totalt utfördes 61 sprickdjupsmätningar med sprickdjupsmätaren på 56 sprickor i 23 olika provbitar som tillhandahölls av Kiwa. De uppmätta sprickdjupen jämfördes sedan med de verkliga sprickdjupen, som bestämdes genom att provbitarna skars upp och mätningarna utfördes direkt på sprickornas tvärsnitt med hjälp av ett optiskt ljusmikroskop. Resultaten av jämförelsen visade att RMG 4015, som använder sig av potentialfallstekniker, var mycket noggrann vid mätning av både töjningsinducerade och alkaliska spänningskorrosionssprickor. Resultaten visade dock också att sprickdjupsmätaren underskattar kloridinducerade spänningskorrosionssprickor, korrosionsutmattningssprickor och spänningskorrosionssprickor/väteförsprödningssprickor i varierande grad. Den viktigaste rekommendationen till Kiwa är därför att ersätta RMG 4015 med en sprickdjupsmätare som istället använder ultraljudsteknik. I examensarbetet undersöktes också möjligheterna att förbättra en FE-modell som Kiwa tagit fram i ett tidigare projekt som omfattade en analys av en sprucken komponent. En provbit från denna komponent ingick i det nuvarande programmet för sprickdjupsmätning. Spänningsfördelningen i den ursprungliga modellen representerade inte de sprickor som fanns i den verkliga strukturen och det misstänktes vara resultatet av vissa randvillkor som inte motsvarade de som verkar i det verkliga rörsystemet. Vissa justeringar av randvillkoren och kontaktytorna gjordes, och en ny förbättrad modell med en bättre representativ spänningsfördelning hittades.

This thesis presents an approach for configuring and calibrating a network of RGB-D sensors used to guide a robotic arm to interact with objects that get rapidly modeled in 3D. The system is based on Microsoft Kinect sensors for 3D data acquisition. The work presented here also details an analysis and experimental study of the Kinect’s depth sensor capabilities and performance. The study comprises examination of the resolution, quantization error, and random distribution of depth data. In addition, the effects of color and reflectance characteristics of an object are also analyzed. The study examines two versions of Kinect sensors, one dedicated to operate with the Xbox 360 video game console and the more recent Microsoft Kinect for Windows version. The study of the Kinect sensor is extended to the design of a rapid acquisition system dedicated to large workspaces by the linkage of multiple Kinect units to collect 3D data over a large object, such as an automotive vehicle. A customized calibration method for this large workspace is proposed which takes advantage of the rapid 3D measurement technology embedded in the Kinect sensor and provides registration accuracy between local sections of point clouds that is within the range of the depth measurements accuracy permitted by the Kinect technology. The method is developed to calibrate all Kinect units with respect to a reference Kinect. The internal calibration of the sensor in between the color and depth measurements is also performed to optimize the alignment between the modalities. The calibration of the 3D vision system is also extended to formally estimate its configuration with respect to the base of a manipulator robot, therefore allowing for seamless integration between the proposed vision platform and the kinematic control of the robot. The resulting vision-robotic system defines the comprehensive calibration of reference Kinect with the robot. The latter can then be used to interact under visual guidance with large objects, such as vehicles, that are positioned within a significantly enlarged field of view created by the network of RGB-D sensors. The proposed design and calibration method is validated in a real world scenario where five Kinect sensors operate collaboratively to rapidly and accurately reconstruct a 180 degrees coverage of the surface shape of various types of vehicles from a set of individual acquisitions performed in a semi-controlled environment, that is an underground parking garage. The vehicle geometrical properties generated from the acquired 3D data are compared with the original dimensions of the vehicle.

This thesis presents an approach for configuring and calibrating a network of RGB-D sensors used to guide a robotic arm to interact with objects that get rapidly modeled in 3D. The system is based on Microsoft Kinect sensors for 3D data acquisition. The work presented here also details an analysis and experimental study of the Kinect’s depth sensor capabilities and performance. The study comprises examination of the resolution, quantization error, and random distribution of depth data. In addition, the effects of color and reflectance characteristics of an object are also analyzed. The study examines two versions of Kinect sensors, one dedicated to operate with the Xbox 360 video game console and the more recent Microsoft Kinect for Windows version. The study of the Kinect sensor is extended to the design of a rapid acquisition system dedicated to large workspaces by the linkage of multiple Kinect units to collect 3D data over a large object, such as an automotive vehicle. A customized calibration method for this large workspace is proposed which takes advantage of the rapid 3D measurement technology embedded in the Kinect sensor and provides registration accuracy between local sections of point clouds that is within the range of the depth measurements accuracy permitted by the Kinect technology. The method is developed to calibrate all Kinect units with respect to a reference Kinect. The internal calibration of the sensor in between the color and depth measurements is also performed to optimize the alignment between the modalities. The calibration of the 3D vision system is also extended to formally estimate its configuration with respect to the base of a manipulator robot, therefore allowing for seamless integration between the proposed vision platform and the kinematic control of the robot. The resulting vision-robotic system defines the comprehensive calibration of reference Kinect with the robot. The latter can then be used to interact under visual guidance with large objects, such as vehicles, that are positioned within a significantly enlarged field of view created by the network of RGB-D sensors. The proposed design and calibration method is validated in a real world scenario where five Kinect sensors operate collaboratively to rapidly and accurately reconstruct a 180 degrees coverage of the surface shape of various types of vehicles from a set of individual acquisitions performed in a semi-controlled environment, that is an underground parking garage. The vehicle geometrical properties generated from the acquired 3D data are compared with the original dimensions of the vehicle.

Plus de vingt ans après la découverte de la supraconductivité à haute température critique, le mécanisme physique sous-jacente n'est pas encore bien cerné. En 2008, la découverte d'une nouvelle famille de supraconducteurs à haute température critique, les supraconducteurs à base de fer, a donné l'espoir de trouver une compréhension plus profonde des mécanismes de ce type de supraconductivité. Synthétiser des l'échantillons de grande qualité, la caractérisation des propriétés supraconductrices, l'étude des symétrices du gap et du paramètre d'ordre sont des étapes essentielles pour révéler le mécanisme. La connaissance précise du mécanisme permettra de profiter pleinement des propriétés remarquables de ces matériaux dans leurs applications industrielles si prometteuses. La thèse décrit d'abord la croissance de monocristaux de Ba$_{1-x}$K$_x$Fe$_2$As$_2$ et l'étude de leurs propriétés supraconductrices, menant vers la proposition d'une structure de gap du supraconducteur et d'un paramètre d'ordre pour les supraconducteurs à base de fer Ba-122 à partir de mesures de résistivité, de sondes à effect Hall, de spectroscopie d'Andreev en mode point-contact et de l'imagerie magnétique par la microscopie à nano-squid.Dans le chapitre 1, les événements historiques les plus marquants de la supraconductivité sont rappelés, les propriétés essentielles des supraconducteurs et le dévelopment des théories de la supraconductivité sont esquissés avant de présenter brièvement la découverte des supraconducteurs à base de fer et de donner un aperçu des questions actuelles de recherche dans ce domaine.Dans le chapitre 2, la procédure de croissance de monocristaux de Ba$_{1-x}$K$_x$Fe$_2$As$_2$ par la méthode de "self-flux", leur caractérisation par diffraction et par l'analyse de dispersion d'énergie des rayons X et la sensibilité des mesures de résistivité et de susceptibilité AC sont décrites. Puis nous présentons quelques résultats des mesures de la résistivité dépendante de la température de monocristaux du composé Ba$_{1-x}$K$_x$Fe$_2$As$_2$ (0,23 $\leq x \leq$ 0,4) sous champs magnétiques allant jusqu'à 9 T et dépendante de l'angle.Dans le chapitre 3, nous exposons quelques points essentiels du système de mesure à base de sonde de Hall que nous avons construit. Ensuite, nous présentons des mesures d'aimantation locale et globale sur des polycristaux de SmFeAsO$_{0.9}$F$_{0.1}$ synthétisés à haute pression, et de monocristaux de Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ effectuées par sonde de Hall et VSM.Dans le chapitre 4, nous donnons une brève introduction à la spectroscopie d'Andreev en mode point-contact, puis nous appliquons cette technique à des monocristaux de Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ et à une série de monocristaux de BaFe$_{2-x}$Ni$_x$As$_2$ couvrant une large gamme de dopage.Dans le chapitre 5, le développement d'un microscope de force à nano-SQUID et les mesures effectuées sur un film Rhénium d'épaisseur de 80 nm sont présentés. Le microscope peut acquérir des images topographiques et magnétiques simultanément. La plage de balayage maximale à 0.8 K est de \unit{70} {\micro\meter} $\times$ \unit{85}{\micro\meter} et sa résolution magnétique est d'environ $1,5 \times10^{-4}\Phi_0/\sqrt{\textrm{Hz}}$. Dans le chapitre 6, nous présentons quelques résultats des mesures de $\lambda$ par imagerie par microscopie de force à nano-squid sur des monocristaux de Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$, couvrant tout le diagramme de phase. Sur les m\^{e}mes cristaux ont été effectuées des mesures du premier champ critique, de la variation de fréquence d'un oscillateur à diode tunnel et de la capacité calorifique.Enfin, au chapitre 7, un résumé détaillé et critique est présenté. / More than twenty years after the discovery of high temperature superconductors, the underlying physical mechanism is still not well understood. In 2008, the discovery of a new family of high temperature superconductors, the iron-based superconductors, provided us a new chance to understand the high temperature superconductivity. Synthesizing high quality sample, detecting the basic superconducting properties, the gap structure and order parameter symmetry are essential steps in revealing the mechanism and application of new superconductors. This dissertation describes the growth of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ single crystals and the study of superconducting properties, gap structure and order parameter on Ba-122 iron-based superconductors with resistivity, Hall probe, point contact Andreev reflection spectroscopy and scanning nano-squid microscopy measurements. Some historical events concerning superconductivity are recalled, and some key properties and theories of superconductivity are presented in Chapter 1. Then we will briefly introduce the discovery and current research situation of the iron-based superconductors. In Chapter 2, the growth procedure of Ba$_{1-x}$K$_x$Fe$_2$As$_2$ single crystals with self-flux method, and the characterization of the crystals with diffraction and energy dispersive analysis of x-ray, AC susceptibility and resistivity measurements are described. Then we report some results from temperature dependent resistivity measurements on Ba$_{1-x}$K$_x$Fe$_2$As$_2$ (0.23 $\leq x \leq$ 0.4) single crystals in magnetic fields up to 9 T and angle dependent resistivity measurements on Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ single crystals. In Chapter 3, we introduce some details about a Hall probe measurement system we built. Then we present local and global magnetization measurements on high pressure SmFeAsO$_{0.9}$F$_{0.1}$ polycrystals and Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ single crystals with Hall probe and VSM.In Chapter 4, we give a brief introduction about point contact Andreev reflection spectroscopy, then we report the measurements on Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ single crystal and a series of electron-doped BaFe$_{2-x}$Ni$_x$As$_2$ single crystals over a wide doping range.In Chapter 5, the development of a scanning nano-SQUID force microscope and measurements performed on a 80 nm Rhenium film are presented. The microscope can take topographic and magnetic images simultaneously. The maximal scanning range is \unit{70}{\micro\meter} $\times$ \unit{85}{\micro\meter} and the magnetic resolution is about $1.5 \times10^{-4}\Phi_0/\sqrt{\textrm{Hz}}$. In Chapter 6, we present some results from lower critical field, tunnel diode oscillator, heat capacity and scanning nano-squid microscopy measurements on systematic doped Ba(Fe$_{1-x}$Ni$_x$)$_2$As$_2$ single crystals..Finally, in Chapter 7, a detailed summary is presented.