In this study, the weather impact on lidar signals has been researched. A lidar system was placed with a target at approximately 90 m and has together with a weather station collected data for about a year before this study. By using the raw detector data from the lidar, the full waveform can be obtained and the amplitude of the return pulse can be calculated. Atmospheric attenuation of lidar signals is often modeled using the lidar equation, which predicts an exponential decrease in energy over the distance. The factor in the exponent is referred to as the extinction coefficient and it is the main property studied in this thesis. By utilizing models for the extinction coefficient under different weather conditions, it is possible to simulate the performance of the lidar.  The extinction coefficient was calculated using different empirical models. The empirical models investigated in this thesis are the Kim and Kruse models for known visibility, the Al Naboulsi model for different types of fog with known visibility, the Carbonneau model for known precipitation amount in rainy conditions, and a similar model for snowy conditions. For the case of rain, a physical model was also used, which is derived through Mie theory. The physical model requires a particle size distribution, which is the number of particles of a certain radius per unit volume. A particle size distribution for rain was generated using the Ulbrich raindrop size distribution, using the precipitation amount recorded by the weather station. Particle size distributions for radiation and advection fog were also simulated.  The measured attenuation in lidar signals was compared to the predicted attenuation that was calculated using different models for the extinction coefficient in the lidar equation. Generally, the models tend to underestimate the amplitude of the return pulse. This can partially be explained by the assumptions used to derive the lidar equation, which neglects all augmentation of the beam. The visibility models gave more accurate results compared to the precipitation models. This was expected, since visibility is defined as a measure of attenuation and precipitation amount is not.  When a lidar signal is emitted, the light will be reflected from optical surfaces within the lidar and cause a pulse to be detected. This pulse is referred to as the zeropulse. In the first couple of meters of the transmission, we expect to see some backscattered light from adverse weather, since the detector has a larger solid angle at shorter distances. This returned light will be combined with the zeropulse and cause it to expand in width. By examining the zeropulse, it was possible to observe a difference between the average zeropulse under some different weather conditions. This leads to the conclusion that it may be possible to extract some information about current weather conditions from the zeropulse data, given that there is little ambient light and snowy weather conditions.  By integrating the zeropulse, variations in the shape of the zeropulse could be described by a single value. Then by separating the data into low and high visibility populations, the zeropulse integral could be used to predict the visibility. The conclusion was that the zeropulse integral can accurately predict whether visibility is above or below a threshold value, given that there is little ambient light and the visibility is known to be below 19950 m.

Na barreira regressiva da Pinheira, são reconhecidos quatro ambientes deposicionais costeiros, caracterizados por parâmetros geológicos como a análise de litofácies, estruturas sedimentares, grau de compactação e conteúdo de moluscos. Informações que são analisadas em conjunto com imagens de dados geofísicos obtidas com o método do Radar de Penetração no Solo (GPR – Ground Penetrating Radar) para determinar esses ambientes. O presente trabalho visa a caracterização destes ambientes deposicionais através da análise da amplitude do sinal em traços de antenas com frequências centrais de 80, 100, 200 e 400 MHz em conjunto com os dados de compactação e litológicos de um furo de sondagem. E também mostra o comportamento da atenuação do sinal em relação a umidade presente no ambiente. A análise dos traços permitiu a identificação dos contatos entre os ambientes já descritos para barreiras regressivas, mostrando variação no valor das amplitudes (decréscimo ou aumento) em conjunto com a variação no grau de compactação, que evidenciam em subsuperfície a mudança entre os ambientes de cordões litorâneos, backshore/foreshore e shoreface superior e inferior. A interferência da umidade na atenuação do sinal nos dados analisados pode ser observada apenas nos primeiros 0,5 m. Demonstrando que a pluviosidade não é um fator de relevância para atenuação do sinal em ambientes arenosos onde o nível da água é próximo a superfície. A análise dos radargramas para todas as antenas, permitiu a identificação dos padrões de refletores já descritos para os ambientes da área de estudo e a antena com frequência central de 200 MHz apresentou maior resolução para a definição de todos os ambientes. / In the Pinheira regressive barrier, four coastal depositional environments are recognized, characterized by geological parameters such as lithofacies analysis, sedimentary structures, compaction degree and set of mollusks. Information that is analyzed together with images of geophysical data obtained with the Ground Penetrating Radar (GPR) method to determine these environments. The present work aims to characterize these depositional environments by analyzing the signal amplitude in traces with central frequencies antennas of 80, 100, 200 and 400 MHz in conjunction with the compaction and lithological data of a drill hole. It also shows the behavior of signal attenuation in relation to the humidity present in the environment. The analysis of the traces allowed the identification of the contacts between the environments already described for regressive barriers, showing variation in the value of the amplitudes (decrease or increase), together with the variation in the degree of compaction, which evidences in subsurface the change between the environments of foredune ridges, backshore/foreshore and upper and lower shoreface. The interference of humidity in attenuation of the signal in the studied data can be observed only in the first 0.5 m. Rainfall was not relevant for signal attenuation in the studied sandy deposits with water level close to the surface. The analysis of the radargrams for all the antennas allowed the identification of the patterns of reflectors already described for the environments of the study area and the central frequency antenna of 200 MHz showed the highest resolution for the definition of all the environments.

Na barreira regressiva da Pinheira, são reconhecidos quatro ambientes deposicionais costeiros, caracterizados por parâmetros geológicos como a análise de litofácies, estruturas sedimentares, grau de compactação e conteúdo de moluscos. Informações que são analisadas em conjunto com imagens de dados geofísicos obtidas com o método do Radar de Penetração no Solo (GPR – Ground Penetrating Radar) para determinar esses ambientes. O presente trabalho visa a caracterização destes ambientes deposicionais através da análise da amplitude do sinal em traços de antenas com frequências centrais de 80, 100, 200 e 400 MHz em conjunto com os dados de compactação e litológicos de um furo de sondagem. E também mostra o comportamento da atenuação do sinal em relação a umidade presente no ambiente. A análise dos traços permitiu a identificação dos contatos entre os ambientes já descritos para barreiras regressivas, mostrando variação no valor das amplitudes (decréscimo ou aumento) em conjunto com a variação no grau de compactação, que evidenciam em subsuperfície a mudança entre os ambientes de cordões litorâneos, backshore/foreshore e shoreface superior e inferior. A interferência da umidade na atenuação do sinal nos dados analisados pode ser observada apenas nos primeiros 0,5 m. Demonstrando que a pluviosidade não é um fator de relevância para atenuação do sinal em ambientes arenosos onde o nível da água é próximo a superfície. A análise dos radargramas para todas as antenas, permitiu a identificação dos padrões de refletores já descritos para os ambientes da área de estudo e a antena com frequência central de 200 MHz apresentou maior resolução para a definição de todos os ambientes. / In the Pinheira regressive barrier, four coastal depositional environments are recognized, characterized by geological parameters such as lithofacies analysis, sedimentary structures, compaction degree and set of mollusks. Information that is analyzed together with images of geophysical data obtained with the Ground Penetrating Radar (GPR) method to determine these environments. The present work aims to characterize these depositional environments by analyzing the signal amplitude in traces with central frequencies antennas of 80, 100, 200 and 400 MHz in conjunction with the compaction and lithological data of a drill hole. It also shows the behavior of signal attenuation in relation to the humidity present in the environment. The analysis of the traces allowed the identification of the contacts between the environments already described for regressive barriers, showing variation in the value of the amplitudes (decrease or increase), together with the variation in the degree of compaction, which evidences in subsurface the change between the environments of foredune ridges, backshore/foreshore and upper and lower shoreface. The interference of humidity in attenuation of the signal in the studied data can be observed only in the first 0.5 m. Rainfall was not relevant for signal attenuation in the studied sandy deposits with water level close to the surface. The analysis of the radargrams for all the antennas allowed the identification of the patterns of reflectors already described for the environments of the study area and the central frequency antenna of 200 MHz showed the highest resolution for the definition of all the environments.

Na barreira regressiva da Pinheira, são reconhecidos quatro ambientes deposicionais costeiros, caracterizados por parâmetros geológicos como a análise de litofácies, estruturas sedimentares, grau de compactação e conteúdo de moluscos. Informações que são analisadas em conjunto com imagens de dados geofísicos obtidas com o método do Radar de Penetração no Solo (GPR – Ground Penetrating Radar) para determinar esses ambientes. O presente trabalho visa a caracterização destes ambientes deposicionais através da análise da amplitude do sinal em traços de antenas com frequências centrais de 80, 100, 200 e 400 MHz em conjunto com os dados de compactação e litológicos de um furo de sondagem. E também mostra o comportamento da atenuação do sinal em relação a umidade presente no ambiente. A análise dos traços permitiu a identificação dos contatos entre os ambientes já descritos para barreiras regressivas, mostrando variação no valor das amplitudes (decréscimo ou aumento) em conjunto com a variação no grau de compactação, que evidenciam em subsuperfície a mudança entre os ambientes de cordões litorâneos, backshore/foreshore e shoreface superior e inferior. A interferência da umidade na atenuação do sinal nos dados analisados pode ser observada apenas nos primeiros 0,5 m. Demonstrando que a pluviosidade não é um fator de relevância para atenuação do sinal em ambientes arenosos onde o nível da água é próximo a superfície. A análise dos radargramas para todas as antenas, permitiu a identificação dos padrões de refletores já descritos para os ambientes da área de estudo e a antena com frequência central de 200 MHz apresentou maior resolução para a definição de todos os ambientes. / In the Pinheira regressive barrier, four coastal depositional environments are recognized, characterized by geological parameters such as lithofacies analysis, sedimentary structures, compaction degree and set of mollusks. Information that is analyzed together with images of geophysical data obtained with the Ground Penetrating Radar (GPR) method to determine these environments. The present work aims to characterize these depositional environments by analyzing the signal amplitude in traces with central frequencies antennas of 80, 100, 200 and 400 MHz in conjunction with the compaction and lithological data of a drill hole. It also shows the behavior of signal attenuation in relation to the humidity present in the environment. The analysis of the traces allowed the identification of the contacts between the environments already described for regressive barriers, showing variation in the value of the amplitudes (decrease or increase), together with the variation in the degree of compaction, which evidences in subsurface the change between the environments of foredune ridges, backshore/foreshore and upper and lower shoreface. The interference of humidity in attenuation of the signal in the studied data can be observed only in the first 0.5 m. Rainfall was not relevant for signal attenuation in the studied sandy deposits with water level close to the surface. The analysis of the radargrams for all the antennas allowed the identification of the patterns of reflectors already described for the environments of the study area and the central frequency antenna of 200 MHz showed the highest resolution for the definition of all the environments.

In the manufacturing process of mineral wool insulation plates, defects arise, such as unmelted base minerals and uncured binder which gets embedded within the plates. To be able to sort out these defective plates from a manufacturing line, a reliable quality assessment is needed. The aim is to find an ultrasonic non-destructive testing method that can identify the embedded defects. This was achieved through experiments on defective insulation plates using three different ultrasonic non-destructive testing methods that were of interest. These methods were higher harmonics, pulse-echo and through transmission. Of these three, the through transmission method showed the most promising results in finding the defects that were sought after. The through transmission method utilizes two aligned transducers, one acting as a transmitter and one as a receiver. When the defective area passes through the sound beam between the transducers the intensity of the beam drops, indicating that a defect is present. The weakened intensity is due to the signal attenuation, mainly caused by the higher density of the defects compared to the base material in the surrounding insulation plate. The method is well suited for being implemented in a production line since it’s a fast method and, therefore, suited for moving objects. More measurements are needed to establish a reliable reference value to consistently distinguish the defects from the surrounding plate. The method was only evaluated in a small scale experimental environment so further experiments on a larger scale are needed to mimic and evaluate the reliability in the real case scenario of the production lines. / I tillverkningsprocessen av isolerskivor i stenull uppstår inneboende defekter i isolerskivorna, dessa defekter består av osmälta basmineraler och ohärdat bindemedel. För att kunna sortera bort dessa skadade skivor från tillverkningslinjen behövs en pålitlig metod för kvalitetsbedömning. Avsikten med det här arbetet är att hitta en oförstörande provningsmetod baserad på ultraljud som kan identifiera de inneboende defekterna. Detta genomfördes genom experiment på defekta isolerskivor med tre olika oförstörande provningsmetoder baserade på ultraljud. Dessa metoderna var, higher harmonics, pitch-echo och through transmission. Through transmission visade lovande resultat i att identifiera de båda typerna av skador. Metoden är baserad på att en sändare sänder ut ultraljud till en mottagare placerad i linje med sändaren. När ett defekt område passerar ultraljudsvågen mellan sändaren och mottagaren försvagas intensiteten av signalen. Försvagningen av signalen beror mestadels på att densiteten är högre hos defekterna än hos basmaterialet i isolerskivan. Denna försvagning indikerar att en defekt befinner sig i mätområdet. Metoden är väl implementerbar i en tillverkningslinje, då det är en snabb metod vilket den behöver vara då objektet är i rörelse. Mer mätningar behövs för att fastställa ett pålitligt referensvärde för att konsekvent kunna sortera ut de defekta isolerskivorna. Metoden är endast utvärderad i en småskalig laborationsmiljö och det behövs fler tester i en större skala undersöka pålitligheten i det verkliga scenariot med tillverkningslinjen.

Wireless transmission is an everyday part of movie production and a tool many people use in their work. Work, on a movie production, is fast, intense, and varies in geographical location almost on a daily basis (sometimes several locations in a day). Despite this, the stream, the transmission, must hold so the crew can work. This thesis explores the different impacts materials have on the transmission (using the Boxx Atom System as a test object). The materials were everyday occurrences such as walls (wood and stone), doors (steel, wood), windows (glass), and humans (the crew). The tests were done in the office of Video Assist Sweden in Stockholm, testing both quality and calculating the link margin. The results gave room for improvement but were interesting and sometimes surprising. Glass is best for a smooth transmission. Wooden doors and human beings’ impact were basically the same and stone and steel had the largest impact. In this thesis, we attempt to explain the results and draw conclusions from them and our own experiences in the field. / Trådlös överföring är en vardaglig del av en filmproduktion och ett verktyg som många använder i sitt arbete. Arbetet med en filmproduktion är snabbt, intensivt och varierar mellan olika platser nästan dagligen (ibland flera platser på en dag). Trots detta måste video transmissionen fungera så att hela teamet kan arbeta effektivt. Detta examensarbete undersöker de olika effekterna material har på transmissionen (med hjälp av Boxx Atom System som testobjekt). Materialen var vardagliga händelser som väggar (trä och sten), dörrar (stål, trä), fönster (glas) och människor (besättningen). Testerna gjordes på Video Assist Swedens kontor i Stockholm, där man testade både kvalitet och beräknade länk-marginalen. Resultaten gav utrymme för förbättringar men var intressanta och ibland överraskande. Glas är bäst för en smidig överföring. Träs och människors påverkan var i princip densamma och sten och stål hade störst påverkan. I detta examensarbete försöker vi förklara resultaten och dra slutsatser från dem och våra egna erfarenheter inom området.

Wissenschaftliche Untersuchungen von terrestrischen und aquatischen Ökosystemen erfordern präzise Informationen über die dreidimensionale Struktur des ökologischen Systems. Full-waveform Flugzeuglaserscannerdaten eignen sich hervorragend zur Charakterisierung von Ökosystemen und bilden eine ideale Basis für die vollständige volumetrische Repräsentation der Vegetations- und Gewässerstruktur in einem Voxelraum. Die Voxelattribute werden dabei aus der digitalisierten Wellenform abgeleitet. Jeder emittierte Laserpuls wird von Dämpfungseffekten beeinflusst, die durch Teilreflexionen auf seinem Weg durch die unterschiedlichen Vegetations- oder Wasserschichten entstehen. Dadurch ist die Struktur im unteren Bereich der empfangenen Rohsignale unterrepräsentiert. Die im Rahmen dieser Arbeit entwickelten innovativen Methoden zur Analyse von full-waveform Daten ermöglichen die Generierung einer radiometrisch korrigierten Voxelraumrepräsentation. Voraussetzung dafür ist die numerisch stabile Rekonstruktion des effektiven differentiellen Rückstreuquerschnitts mit geeigneten Entfaltungs- und Regularisierungsverfahren. Das Kernstück der Analyse bildet die Beschreibung der Signaldämpfung mit Hilfe geeigneter Modelle. Auf Grundlage dieser Modelle wurden neuartige Korrekturverfahren zur Kompensation der Signaldämpfung erarbeitet, wobei der Korrekturterm direkt aus dem differentiellen Rückstreuquerschnitt abgeleitet wird. Die Grundidee der entwickelten Methode ist das schrittweise Anheben der Signalintensität in Abhängigkeit von der individuellen Historie jedes Laserpulses. Die Resultate der vorliegenden Arbeit tragen dazu bei, die in full-waveform Daten enthaltenen Informationen über die Vegetations- und Gewässerstruktur zugänglich zu machen. Weiterhin zeigen die hier präsentierten Ergebnisse, dass die Limitierungen bestehender Auswertemethoden, welche weitgehend auf die Extraktion diskreter Maxima und die Erzeugung volumetrischer Repräsentationen aus diskreten 3D Punktwolken beschränkt sind, überwunden werden können. / The scientific investigation of terrestrial and aquatic ecosystems requires precise information on the three-dimensional structure of the ecologic system. Full-waveform airborne laser scanner data are an ideal basis for the complete volumetric representation of vegetation and water structure in a voxel space. Due to attenuation effects, caused by partial reflections during the laser pulse propagation through the vegetation or water column, each individual laser pulse echo is significantly modified. As a result, the structure in the lower parts of the vegetation or water column is underrepresented in the digitized waveform. Within this research, novel and innovative methods were developed, which enable the generation of a radiometrically correct voxel space representation. Therefore, a numerically stable reconstruction of the effective differential backscattering cross section utilizing appropriate deconvolution and regularization techniques is required. The essential element of the analysis is the description of the signal attenuation using applicable mathematical models. For this purpose, novel correction methods compensating the signal attenuation based on these models were developed. The correction term is directly derived from the differential backscatter cross section. The basic idea is a gradually increase of the signal amplitudes depending on the individual history of each laser pulse. The results gained in this work contribute to an improved access to the information on vegetation and water structure, contained in full-waveform laser scanner data. Furthermore, it is possible to overcome limitations of existing approaches, which are mainly based on the extraction of discrete maxima.