Spelling suggestions: "subject:"depth"" "subject:"epth""
131 |
Aerosol Retrievals from CALIPSO Lidar Ocean Surface ReturnsVenkata, Srikanth, Reagan, John 09 December 2016 (has links)
This paper describes approaches to retrieve important aerosol results from the strong lidar return signals that are received by the space-borne CALIPSO lidar system after reflecting off-ocean surfaces. Relations, from which the theoretically expected values of area under ocean surface returns can be computed, are presented. A detailed description of the lidar system response to the ocean surface returns and the processes of sampling and averaging of lidar return signals are provided. An effective technique that reconstructs the lidar response to surface returnsstarting from down-linked samplesand calculates the area under it, has been developed and described. The calculated area values are validated after comparing them to their theoretically predicted counterpart values. Methods to retrieve aerosol optical depths (AODs) from these calculated areas are described and retrieval results are presented, including retrieval comparison with independent AOD measurements made by an airborne High Spectral Resolution Lidar (HSRL) that yielded quite good agreement. Techniques and results are also presented on using the spectral ratios of the surface response areas to determine spectral ratios of aerosol round-trip transmission and AOD spectral difference, without need of a specific/accurate ocean-surface reflectance model.
|
132 |
View Rendering for 3DTVMuddala, Suryanarayana Murthy January 2013 (has links)
Advancements in three dimensional (3D) technologies are rapidly increasing. Three Dimensional Television (3DTV) aims at creating 3D experience for the home user. Moreover, multiview autostereoscopic displays provide a depth impression without the requirement for any special glasses and can be viewed from multiple locations. One of the key issues in the 3DTV processing chain is the content generation from the available input data format video plus depth and multiview video plus depth. This data allows for the possibility of producing virtual views using depth-image-based rendering. Although depth-image-based rendering is an efficient method, it is known for appearance of artifacts such as cracks, corona and empty regions in rendered images. While several approaches have tackled the problem, reducing the artifacts in rendered images is still an active field of research. Two problems are addressed in this thesis in order to achieve a better 3D video quality in the context of view rendering: firstly, how to improve the quality of rendered views using a direct approach (i.e. without applying specific processing steps for each artifact), and secondly, how to fill the large missing areas in a visually plausible manner using neighbouring details from around the missing regions. This thesis introduces a new depth-image-based rendering and depth-based texture inpainting in order to address these two problems. The first problem is solved by an edge-aided rendering method that relies on the principles of forward warping and one dimensional interpolation. The other problem is addressed by using the depth-included curvature inpainting method that uses appropriate depth level texture details around disocclusions. The proposed edge-aided rendering method and depth-included curvature inpainting methods are evaluated and compared with the state-of-the-art methods. The results show an increase in the objective quality and the visual gain over reference methods. The quality gain is encouraging as the edge-aided rendering method omits the specific processing steps to remove the rendering artifacts. Moreover, the results show that large disocclusions can be effectively filled using the depth-included curvature inpainting approach. Overall, the proposed approaches improve the content generation for 3DTV and additionally, for free view point television.
|
133 |
Determining the Quality of Human Movement using Kinect DataThati, Satish Kumar, Mareedu, Venkata Praneeth January 2017 (has links)
Health is one of the most important elements in every individual’s life. Even though there is much advancement in science, the quality of healthcare has never been up to the mark. This appears to be true especially in the field of Physiotherapy. Physiotherapy is the analysis of human joints and bodies and providing remedies for any pains or injuries that might have affected the physiology of a body. To give patients a top notch quality health analysis and treatment, either the number of doctors should increase, or there should be an alternative replacement for a doctor. Our Master Thesis is aimed at developing a prototype which can aid in providing healthcare of high standards to the millions. Methods: Microsoft Kinect SDK 2.0 is used to develop the prototype. The study shows that Kinect can be used both as Marker-based and Marker less systems for tracking human motion. The degree angles formed from the motion of five joints namely shoulder, elbow, hip, knee and ankle were calculated. The device has infrared, depth and colour sensors in it. Depth data is used to identify the parts of the human body using pixel intensity information and the located parts are mapped onto RGB colour frame. The image resulting from the Kinect skeleton mode was considered as the images resulting from the markerless system and used to calculate the angle of the same joints. In this project, data generated from the movement tracking algorithm for Posture Side and Deep Squat Side movements are collected and stored for further evaluation. Results: Based on the data collected, our system automatically evaluates the quality of movement performed by the user. The system detected problems in static posture and Deep squat based on the feedback on our system by Physiotherapist.
|
134 |
Vinhaça concentrada de cana-de-açúcar: monitoramento das propriedades químicas do solo e mineralização líquida de nitrogênio / Concentrated vinasse from sugarcane: monitoring of soil chemical properties and net nitrogen mineralizationSilva, Alinne da 16 July 2012 (has links)
A geração de grande quantidade de vinhaça resultante da produção de etanol induziu questionamentos a respeito de sua disposição e possível armazenamento. No Estado de São Paulo, a norma P4.231 da CETESB restringiu a aplicação de vinhaça em muitos solos, resultando na necessidade de distribuí-la em áreas distantes da usina. Porém, devido a grande quantidade de água no resíduo, o transporte torna-se inviável do ponto de vista econômico. Uma alternativa para diminuir os custos de transporte é reduzir o volume por evaporação, originando a vinhaça concentrada (VC). No entanto, as temperaturas altas durante o processo de concentração provocam modificações na matéria orgânica, consequentemente, alterando a dinâmica das transformações do N no solo e, considerando ainda que a sua aplicação é realizada na linha de plantio, diferentemente da vinhaça não concentrada (VNC) que é aplicada em área total, pouco se conhece sobre os efeitos no solo e a sua eficiência agronômica. Com o objetivo de (1) conhecer algumas propriedades físico-químicas da VC e compará-la com a VNC, (2) avaliar os efeitos das doses de VC na fertilidade do solo, percolação de íons, produtividade de soqueira de cana-de-açúcar e qualidade tecnológica dos colmos e (3) determinar a mineralização líquida do N (Nm) foram: (I) coletadas amostras de VC e VNC em duas usinas entre os anos de 2010 e 2011, (II) realizado um experimento na cidade de Batatais, SP, em uma área comercial de cana-de-açúcar, (III) conduzido um experimento de incubação aeróbia com os objetivos de determinar o Nm e, através do ajuste a equação de primeira ordem, determinar a mineralização potencial do N (N0), a constante de mineralização do N (k) e (4) parametrizar o módulo SoilN do modelo APSIM para solo que recebeu aplicação de vinhaça. Verificou-se que o processo de concentração da vinhaça promove grande variação no teor de alguns elementos, especialmente o Na+ e as formas de nitrogênio amoniacal e nítrica. A aplicação de 30 m3 ha-1 de VC na linha da cana promoveu aumento nas concentrações de Cl-, NO3 -, Ca+2, Mg+2 e SO4 -2 nas soluções coletadas pelos extratores a 0,80 m de profundidade. De maneira geral foi observado aumento do pH, CTC e dos teores dos cátions trocáveis em função das doses, ao mesmo tempo que os valores de m% decresceram, resultando dessa forma em maior disponibilidade de nutrientes, aumento da fertilidade do solo e consequentemente aumento de produtividade, pois os tratamentos com VC promoveram ganhos de 8 Mg ha-1 em relação ao tratamento controle e, mesmo pela grande quantidade de K+ concentrado na linha de plantio as características tecnológicas dos colmos não foram prejudicadas. Com base nos valores de Nm, N0 e k, pode-se concluir que ocorreu imobilização do N mineral pela biomassa microbiana nos tratamentos com VC. O módulo SoilN do APSIM apresentou bom desempenho em simular a produção de NO3 -, pois a nitrificação calculada diariamente a partir do modelo se ajustou adequadamente aos valores de nitrato observados nas incubações; o modelo foi bem sucedido em calcular as perdas de N no tratamento com a maior dose de VNC a partir dos valores da curva de retenção e do volume de água aplicada no solo. / In São Paulo State, the legislation from CETESB restricts the application of vinasse in many soils, resulting in the need to distribute it in areas distant from the mill. However, due to the large amount of waste water, the transport becomes unfeasible economically. An alternative is to reduce the volume by evaporation, resulting in the concentrated vinasse (CV). But, high temperatures during the evaporation cause changes in the organic matter. So, considering that its application is in the row of sugarcane, unlike the not concentrated vinasse (NCV) which is applied in the total area, the objectives were (1) study some physicochemical properties of the CV and compare it with NCV, (2) evaluate the effects of CV in soil fertility, ions percolation, productivity, and technological quality of stems and (3) evaluate the net N mineralization (Nm). (I) Samples of CV and NCV were collected at two sugarcane mills in 2010 and 2011, (II) an experiment was conducted in São Paulo, in a commercial sugarcane area, (III) an aerobic incubation was conducted to determine Nm, potential N mineralization (N0), rate of N mineralization (k) and (IV) parameterize SoilN APSIM model for soil with vinasse application. It was found that the evaporation of the vinasse leads to greater variation in the concentration of some elements, especially Na+ and ammoniacal and nitrate nitrogen. 30 m3 ha-1 of CV applied in the sugarcane line caused high concentration of Cl-, NO3 -, Ca +2, Mg+2 and SO4 -2 in the soil solutions collected at 0.80 m. There were increase in pH, CEC and the content of the cations, while the values of m% decreased, resulting in availability of nutrient, increasing the soil fertility and productivity. CV promoted gains of 8 Mg ha-1 compared to control and, even the large amount of K+ concentrated in the sugarcane line, the technological characteristics of the stems were not impaired. Based on the values of Nm, k and N0, we can conclude that the mineral N was immobilized by microbial biomass in CV treatments. The APSIM showed good performance to simulate NO3 - production. The nitrification calculated daily from the model was successful to fit to the values observed. The model was successful to calculate N losses in treatment with the highest dose of NCV.
|
135 |
Gesture passwords: concepts, methods and challengesWu, Jonathan 21 June 2016 (has links)
Biometrics are a convenient alternative to traditional forms of access control such as passwords and pass-cards since they rely solely on user-specific traits. Unlike alphanumeric passwords, biometrics cannot be given or told to another person, and unlike pass-cards, are always “on-hand.” Perhaps the most well-known biometrics with these properties are: face, speech, iris, and gait. This dissertation proposes a new biometric modality: gestures.
A gesture is a short body motion that contains static anatomical information and changing behavioral (dynamic) information. This work considers both full-body gestures such as a large wave of the arms, and hand gestures such as a subtle curl of the fingers and palm. For access control, a specific gesture can be selected as a “password” and used for identification and authentication of a user. If this particular motion were somehow compromised, a user could readily select a new motion as a “password,” effectively changing and renewing the behavioral aspect of the biometric.
This thesis describes a novel framework for acquiring, representing, and evaluating gesture passwords for the purpose of general access control. The framework uses depth sensors, such as the Kinect, to record gesture information from which depth maps or pose features are estimated. First, various distance measures, such as the log-euclidean distance between feature covariance matrices and distances based on feature sequence alignment via dynamic time warping, are used to compare two gestures, and train a classifier to either authenticate or identify a user. In authentication, this framework yields an equal error rate on the order of 1-2% for body and hand gestures in non-adversarial scenarios. Next, through a novel decomposition of gestures into posture, build, and dynamic components, the relative importance of each component is studied. The dynamic portion of a gesture is shown to have the largest impact on biometric performance with its removal causing a significant increase in error. In addition, the effects of two types of threats are investigated: one due to self-induced degradations (personal effects and the passage of time) and the other due to spoof attacks. For body gestures, both spoof attacks (with only the dynamic component) and self-induced degradations increase the equal error rate as expected. Further, the benefits of adding additional sensor viewpoints to this modality are empirically evaluated. Finally, a novel framework that leverages deep convolutional neural networks for learning a user-specific “style” representation from a set of known gestures is proposed and compared to a similar representation for gesture recognition. This deep convolutional neural network yields significantly improved performance over prior methods.
A byproduct of this work is the creation and release of multiple publicly available,
user-centric (as opposed to gesture-centric) datasets based on both body and hand gestures.
|
136 |
Avaliação da profundidade de polimerização através de testes de microdureza de duas resinas compostas de matrizes distintas em diferentes densidades de energia e períodos, utilizando LED como fonte fotoativadora / Evaluation of depth of cure by testing microhardness of two resin composites of different matrices in different energy densities and periods, using LED as a source photopolymerizationCardia, Guilherme Saintive 31 May 2011 (has links)
O presente estudo objetivou avaliar a profundidade de polimerização através de testes de microdureza em dois tipos de resina composta com matrizes distintas utilizando um aparelho fotoativador do tipo LED, empregando-se diferentes densidades de energia, sendo avaliados no período inicial (baseline) e após 7 dias. O método utilizado foi o teste de dureza Knoop em amostras de dois compósitos fotoativáveis (P 90, 3M/ESPE, cor A2; Z 250, 3M/ESPE, cor A2). Os corpos-de-prova foram subdivididos em 8 grupos (n=10), metade realizado com cada resina testada. Cada grupo foi definido através de diferentes densidades de energia (600 mW/cm2 x 40s; 1000 mW/cm2 x 40s; 1000 mW/cm2 x 20s; 1400 mW/cm2 x 20s), cada corpo-de- prova obtinha 4 medidas, diferentes profundidades (0, 1, 2 e 3 mm). Cada corpo-de-prova foi confeccionado com o auxilio de uma matriz metálica, constituída por 3 partes, superior, intermediaria e inferior, cada uma com 1 mm de espessura e orifício central com diâmetro de 5 mm. Sobre cada parte preenchida com resina, era colocado um pedaço de tira de poliéster, sobre o qual, com uma lâmina de vidro era exercida uma pressão para promover uma superfície lisa e plana. A unidade fotoativadora utilizada foi LED, para conseguir as diferentes densidades de potência, anéis de plástico foram acoplados na ponta do aparelho fotoativador. A fotoativação foi realizada com a ponta da unidade fotoativadora em contato com a tira de poliéster colocada na parte superior do corpo-de-prova (0 mm). Assim , cada espécime era composto por três partes, cada uma com 1 mm de espessura. Logo após a fotoativação, as partes dos espécimes eram separadas e realizavam-se 5 impressões de dureza Knoop (dureza inicial), com carga de 50g durante 30s, em 4 superfícies, que eram: 1ª) superfície superior da parte superior do espécime, voltada para a fonte de luz (0 mm); 2ª) superfície inferior da parte superior do espécime (1 mm); 3ª) superfície inferior da parte intermediária do espécime (2 mm); e 4ª) superfície inferior da parte inferior do espécime (3 mm). Após 7 dias de estocagem numa estufa a 37ºC, novas leituras de dureza eram realizadas (dureza final). Verificou-se que: 1) A resina composta P 90 obteve menores médias dos valores de dureza Knoop em relação à outra resina composta estudada, Z 250; 2) Quanto maior a profundidade, menores alores de dureza Knoop foram mensurados; 3) Valores de dureza Knoop final foram maiores após 7 dias em comparação a dureza Knoop inicial; 4) De acordo com o aumento da densidade de potência, maiores médias dos valores de dureza Knoop foram mensurados. Esses resultados permitem concluir que: 1) A resina melhora sua propriedade de dureza num período de 7 dias; 2) Quanto maior a profundidade, menor a dureza; 3) quanto maior a densidade de potência utilizada neste trabalho, maior dureza foi avaliado; 4) a resina P 90 obteve valores inferiores a resina Z 250 avaliadas nas mesmas condições. / This study aimed to evaluate the depth of cure through microhardness tests on two types of resin composite with different matrices using LED curing unit, using different energy densities and are assessed during the initial (baseline) and after 7 days. Knoop hardness test was performed in samples made of two light cured composites (P 90, 3M/ESPE, A2; Z 250, 3M/ESPE, A2). The specimens were divided into 8 groups (n=10), and half of them were made with each composite resin tested. Each group was defined by different power densities (600 mW/cm2 x 40s, 1000 mW/cm2 x 40s, 1000 mW/cm2 x 20s; mW/cm2 1400 x 20s), each specimens obtained four measures, different depths (0, 1, 2 and 3 mm). Each specimens was made with the aid of a metal matrix, consisting of 3 parts, superior, intermediate and bottom, each with 1 mm thickness and center hole diameter of 5 mm. On each side filled with resin, was placed a piece of polyester strip, on which, with a glass slide was exerted pressure to promote a flat surface. A unit LED curing was used and to achieve different power densities, plastic rings were attached at the tip of the curing unit. The polymerization was carried out with the tip of the curing unit in contact with the polyester strip placed on top of the specimen (0 mm). Thus, each specimen was composed of three parts, each part with 1 mm thick. Immediately after curing, the parts of the specimens were separated and held up five impressions of Knoop hardness (initial hardness), with a load of 50g for 30s on 4 surfaces, which were: 1) the upper surface of the upper specimen directed to the light source (0 mm), 2) lower surface of the upper specimen (1 mm); 3) lower surface of the middle section of the specimen (2 mm) and 4) lower surface of the bottom of the specimen (3 mm). After 7 days of storage in an oven at 37°C, new hardness re adings were made (final hardness). It was found that: 1) The composite P 90 had lower average values of Knoop hardness in relation to the other studied composite, Z 250, 2) The greater the depth, lower Knoop hardness values were measured, 3) Final values of Knoop hardness were higher after 7 days compared with initial hardness, 4) In accordance with the increase of power density, higher average values of Knoop hardness were measured. These results indicate that: 1) The resin improves the hardness property over a period of 7 days, 2) The greater the depth, the lower the hardness, 3) the higher the power density used in this study, higher hardness was evaluated; 4 ) P 90 resin obtained values less than Z 250 resin, evaluated under the same conditions.
|
137 |
A 3D Sub-Surface Characterisation of the Arnager Greensand, South-west Skåne / En 3D ytkarakterisering av Arnager Greensand, södra SverigeDavies Jones, Gregory Marcel January 2019 (has links)
A surface characterisation of the Arnager Greensand in south Sweden, a deep saline aquifer found to be suitable for geological storage of CO2 or energy storage, was undertaken in this thesis. Vintage seismic reflection data only available as scanned tiff images of the final stacked sections were digitized and processed using modern interpretation software to provide new insights into the morphology of the Arnager Greensand and to analyse the reservoir’s potential as an energy storage unit. The primary energy storage method discussed and evaluated was Compressed Air Energy Storage (CAES). This is a modern energy storage method developed as a tool for regulating inherently intermittent renewable energy sources. Such methods are key to the growth of the renewable sector and for providing a competitive alternative to fossil fuels. Moreover, in comparison with other energy storage methods such as battery storage, CAES is known to have strong potential to deliver highperformance energy storage at large scales for relatively low costs compared with any other solution. Previous studies conducted in the 1980’s by Swedegas produced a 2D isochrone surface map of the Arnager Greensand by hand interpolation methods utilizing analogue data collected by Oljeprospektering AB (OPAB, currently Svenska Petroleum). The Geological Survey of Sweden (SGU) has now transferred a vast amount of the historical OPAB dataset to modern digital format. This thesis contributes to those efforts and seeks to find new interpretations from the vintage data. A more comprehensive 3D model of the top of the Arnager Greensand employing the application of modern interpretation software was produced in this study. Strong similarities between morphology and dip-trend have been observed between the surface model generated in this report and the historical Swedegas isochrone surface map. Reservoir properties such as thickness, porosity and permeability gleaned from the earlier reports show the Arnager Greensand to exhibit excellent potential as a storage unit. Preliminary effective capacity estimates by Nordic CCS Competence centre show the Aranger Greensand to be one of the top three storage aquifers in Sweden. These positive appraisals highlight the need for a better characterization of the Aranger Greensand through data digitization and modern interpretation means. This thesis contributes to that endeavour.
|
138 |
Techniques for improved 2-D Kirchhoff prestack depth imagingManuel, Christopher D. January 2002 (has links)
The goal of oil and gas exploration using seismic methods is to accurately locate geological structures that could host such reserves. As the search for these resources tends towards more complex regions, it is necessary to develop methods to extract as much information as possible from the seismic data acquired. Prestack depth imaging is a seismic processing technique that has the capability to produce a realistic depth image of geological structures in complex situations. However, improvements to this technique are required to increase the accuracy of the final depth image and ensure that the targets are accurately located. Although prestack depth imaging possesses the ability to produce a depth image of the Earth, it does have its disadvantages. Three problematic areas in depth imaging are: the computer run times (and hence costs) are excessively high; the success of depth migration is highly dependent upon the accuracy of the interval velocity model; and seismic multiples often obscure the primary reflection events representative of the subsurface geology. Velocity model building accounts for most of the effort in prestack depth imaging and is also responsible for the likelihood of success. However, the more effort that is expended on this process, the greater the cost of producing the required depth section. In addition, multiples remain a problem in complex depth imaging since many attenuation techniques are based assumptions that may only be approximately correct and in addition require a priori information. The Kirchhoff method is considered to be the workhorse in industry for prestack depth imaging. It is a simple and flexible technique to implement, and usually produces acceptable images at a small fraction of the cost of the other depth migration methods. / However, it is highly dependent on a method for calculating the traveltimes that are required for mapping data from the prestack domain to the output depth section. In addition, it is highly dependent on the accuracy of the interval velocity model. Multiples can also be problematic in complex geological scenarios. To improve the quality of the depth section obtained from Kirchhoff depth imaging, these three issues are considered in this thesis. This thesis took on the challenge of developing new techniques for (a) improving the accuracy and efficiency of traveltimes calculated for use in Kirchhoff prestack depth imaging, (b) building the interval velocity model, and (c) multiple attenuation in complex geological areas. Three new techniques were developed and tested using a variety of numerical models. A new traveltime computation method for simulating seismic multiple reflections was tested and compared with a Promax© finite-difference traveltime solver. The same method was also used to improve the computational efficiency whilst retaining traveltime accuracy. This was demonstrated by application to the well-known Marmousi velocity model and a velocity model obtained from analysis of data from the North West Shelf of Western Australia. / A new interval velocity model building technique that utilises the information contained in multiple events was also implemented and tested successfully using a variety of numerical models. Finally, a new processing sequence for multiple attenuation in the prestack depth domain was designed and tested with promising results being observed. Improved accuracy in the depth image can be obtained by combining the three techniques I have developed. These techniques enable this to be achieved by firstly improving traveltime accuracy and computation efficiency. These benefits are then combined with a more accurate interval velocity model and data with a minimal problematic multiple content to produce an accurate depth image. These new techniques for Kirchhoff depth imaging are capable of producing a depth section with improved accuracy, and with increased efficiency, that will aid in the process of seismic interpretation.
|
139 |
Luminance and contrast as depth cuesGovan, Donovan G, n/a January 2007 (has links)
It has long been held that luminance acts as a cue for depth perception. But varying the luminance of a stimulus inevitably alters its contrast with its background. Recent research shows that contrast is a depth cue. I have distinguished two kinds of contrast, external contrast, the contrast of a stimulus with its background, and internal contrast, the contrast within the stimulus. I compared the relative apparent depth of two stimuli (both directly and indirectly; stimuli were either sine-wave filled hemifields, sine-wave filled squares, or plain squares), as their luminances and internal contrasts were varied along with the luminance of their background. I found internal and external contrast to be additive effects, whereby the stimulus with either a higher internal or external contrast appeared nearer. When the internal and external contrasts of the stimuli were equated, luminance acted as an ambiguous cue, with the lighter square appearing nearer for the majority of observers, and farther for a minority. Luminance may act as a depth cues from our experience with artificial lighting (artificial light varies ambiguously with depth). Contrast may act as a depth cue from its usual association with the reduction of contrast of objects with distance through the atmosphere. I conclude that luminance and contrast are independent depth-cues that are caused by two different mechanisms.
|
140 |
Obstacle detection using stereo vision for unmanned ground vehiclesOlsson, Martin January 2009 (has links)
No description available.
|
Page generated in 0.0743 seconds