No description available.

This thesis examines the issues related to calibrating digital cameras and lenses, which is an essential prerequisite for the extraction of precise and reliable 3D metric information from 2D images. The techniques used to calibrate a Canon PowerShot A70 camera with 5.4 mm zoom lens and a professional single lens reflex camera Canon EOS 1Ds Mark II with 35 mm, 85 mm, 135 mm and 200 mm prime lenses are described. The test results have demonstrated that a high correlation exists among some interior and exterior orientation parameters. The correlations are dependent on the parameters being adjusted and the network configuration. Not all of the 11 interior orientation parameters are significant for modelling the camera and lens behaviour. The first two coefficients K1, K2 would be sufficient to describe the radial distortion effect for most digital cameras. Furthermore, the interior orientation parameters of a digital camera and lens from different calibration tests can change. This work has demonstrated that given a functional model that represents physical effects, a reasonably large number of 3D targets that are well distributed in three-dimensional space, and a highly convergent imaging network, all of the usual parameters can be estimated to reasonable values. / Mining Engineering

Mapping of marine benthic flora using remote sensing techniques has, over the past decade, been used to locate environmentally stressed areas in the South Australian marine environment. These studies used panchromatic/colour aerial photography and/or medium resolution multispectral satellite imagery to create a time series showing location and rate of seagrass loss. While successful within their project parameters, these studies were limited by conditions at time of image capture, such as sun-glare, wave action and low contrast in deeper waters due to absorption and scattering. This research thesis reports the successful use of polarisation on the capture of visible and near infra-red optical imagery as a method to minimise these limiting factors. Two experimental test flights were undertaken using commercial off-the-shelf digital cameras mounted in the camera port of a light aircraft. The first flight compared vertical polarisation using co-mounted visible and infra-red cameras. The second flight compared vertical and horizontal polarisation using co-mounted identical visible spectrum cameras. The main finding of this series of airborne polarisation experiments is that sea surface reflection is removed by using vertically polarised filters at, and around, the Brewster angle of 53 degrees off nadir, especially when viewing sunwards. The effect is the same in the visible and infra-red parts of the spectrum. This reflection includes sky reflectance, lambertian sun glare, reflection due to wave action, and turbulence, but not direct solar specular reflection. Vertical polarisation filters improve the imaging of benthic flora compared to horizontally polarised imagery and, by extension, non-polarised imagery. The successful use of polarisation to remove surface reflectance over water is limited to imagery captured at or near the Brewster angle. By using successive overlapping frames this can be achieved, as shown by the experiments. Ideally all of the image should be at the Brewster angle. A conceptual design for a conical optical scanner which builds wide-swath imagery where each pixel in each band is solely a record of the vertically polarised signal at the Brewster Angle is presented as a result of these experiments. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1374494 / Thesis (M.Sc.) - University of Adelaide, School of Earth and Environmental Sciences, 2009

No description available.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

A utilização de detectores de radiação é de imensa importância na área de dosimetria, pois permite a quantificação da dose absorvida no meio. Uma técnica interessante para esta finalidade é o uso de detectores por cintilação. Estudos recentes com cintiladores plásticos e líquidos demonstraram a viabilidade do uso de detecção de cintilação por uma câmera digital com sensor CCD ou CMOS. Desse modo, este trabalho tem como objetivo desenvolver um dosímetro cintilador de baixo custo para viabilidade de seu uso e, de um sistema de detecção de cintilação através de uma câmera digital, para que assim pudesse ser realizada sua caracterização dosimétrica. O sistema dosimétrico foi construído a partir de um cintilador líquido a base de antraceno. Dosimetricamente verificou-se uma linearidade de resposta para a dose de 0,1 a 25,53 Gy, para a taxa de dose de 6,66 Gy/min e uma pequena diminuição da sensibilidade do dosímetro quando aumentada a taxa de dose de irradiação. Com relação à dependência energética, foi verificado um aumento na sensibilidade do dosímetro de 10,8% ao se variar a energia de 100 a 160 kVp. Quando comparado a um cintilador comercial, apresentou uma intensidade de sinal reduzida e, em uma análise de reprodutibilidade, obteve-se uma variação máxima de 2% em relação a repetição de uma mesma medida. O cintilador líquido apresentou baixa estabilidade pré e pós-irradiação, com uma variação de cor e redução do sinal ao decorrer dos dias. Para medidas bidimensionais o sistema montado mostrou-se promissor, uma vez que em medidas de deposição de dose com a profundidade para várias energias de feixes, verificou-se o aumento da penetração da radiação com o aumento da energia do feixe e as medidas de penumbra de um feixe parcialmente blindado com 2 mmPb apresentaram um valor de 1,79 cm, considerando o tipo de tubo gerador e blindagem utilizada. Por toda a caracterização realizada o sistema dosimétrico mostrou-se aplicável para dosimetria, desde que operado considerando as características apresentadas. / The utilization of radiation detector is important in the dosimetric area, because it allow the quantification of absortion dose in the medium. An interesting tehnique for this finalitypurpose is the use of scintillation detector. Recent studies with plastic scintillators and liquid scintillators have demonstrated the feasibility of using scintillation detection by a digital camera with CCD or CMOS sensors. Thus, this study is the intent to develop a low-cost scintillation dosimeter for the feasibility of its use and detection scintillation system through by a digital camera, with the finality of dosimetric characterization. The dosimetric system was constructed from using liquid scintilator based anthracene. A linearity dose response between 0.1 to 25.53 Gy was found for the dose rate of 6.66 Gy/min and the dosimeter sensibility was decreased when the dose rate increased. When varied the energy from 100 to 160 kVp, was verified an increased of 10.8% in the dosimeter sensibility, due the energy dependence. When compared to a commercial dosimeter, it shows signal intensity decreased and, the study of reproducibility, a maximum variation of 2% was obtained in relation to the repetition of the same measure. The liquid scintillator presented low stability before and after irradiation, with a color variation and signal reduction over the days. For two-dimensional measurements the assembled system proved to be promising, since in dose deposition measurements with the depth for several beam energies, the penetration of the radiation was increased with the increase of the beam energy and the penumbra measurements of a narrow beam with 2mmPb presented a value of 1.79 cm, considering the type of generator tube and narrow used. Throughout the characterization carried out the dosimetric system proved to be applicable for dosimetry, if operated considering the characteristics presented.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

A utilização de detectores de radiação é de imensa importância na área de dosimetria, pois permite a quantificação da dose absorvida no meio. Uma técnica interessante para esta finalidade é o uso de detectores por cintilação. Estudos recentes com cintiladores plásticos e líquidos demonstraram a viabilidade do uso de detecção de cintilação por uma câmera digital com sensor CCD ou CMOS. Desse modo, este trabalho tem como objetivo desenvolver um dosímetro cintilador de baixo custo para viabilidade de seu uso e, de um sistema de detecção de cintilação através de uma câmera digital, para que assim pudesse ser realizada sua caracterização dosimétrica. O sistema dosimétrico foi construído a partir de um cintilador líquido a base de antraceno. Dosimetricamente verificou-se uma linearidade de resposta para a dose de 0,1 a 25,53 Gy, para a taxa de dose de 6,66 Gy/min e uma pequena diminuição da sensibilidade do dosímetro quando aumentada a taxa de dose de irradiação. Com relação à dependência energética, foi verificado um aumento na sensibilidade do dosímetro de 10,8% ao se variar a energia de 100 a 160 kVp. Quando comparado a um cintilador comercial, apresentou uma intensidade de sinal reduzida e, em uma análise de reprodutibilidade, obteve-se uma variação máxima de 2% em relação a repetição de uma mesma medida. O cintilador líquido apresentou baixa estabilidade pré e pós-irradiação, com uma variação de cor e redução do sinal ao decorrer dos dias. Para medidas bidimensionais o sistema montado mostrou-se promissor, uma vez que em medidas de deposição de dose com a profundidade para várias energias de feixes, verificou-se o aumento da penetração da radiação com o aumento da energia do feixe e as medidas de penumbra de um feixe parcialmente blindado com 2 mmPb apresentaram um valor de 1,79 cm, considerando o tipo de tubo gerador e blindagem utilizada. Por toda a caracterização realizada o sistema dosimétrico mostrou-se aplicável para dosimetria, desde que operado considerando as características apresentadas. / The utilization of radiation detector is important in the dosimetric area, because it allow the quantification of absortion dose in the medium. An interesting tehnique for this finalitypurpose is the use of scintillation detector. Recent studies with plastic scintillators and liquid scintillators have demonstrated the feasibility of using scintillation detection by a digital camera with CCD or CMOS sensors. Thus, this study is the intent to develop a low-cost scintillation dosimeter for the feasibility of its use and detection scintillation system through by a digital camera, with the finality of dosimetric characterization. The dosimetric system was constructed from using liquid scintilator based anthracene. A linearity dose response between 0.1 to 25.53 Gy was found for the dose rate of 6.66 Gy/min and the dosimeter sensibility was decreased when the dose rate increased. When varied the energy from 100 to 160 kVp, was verified an increased of 10.8% in the dosimeter sensibility, due the energy dependence. When compared to a commercial dosimeter, it shows signal intensity decreased and, the study of reproducibility, a maximum variation of 2% was obtained in relation to the repetition of the same measure. The liquid scintillator presented low stability before and after irradiation, with a color variation and signal reduction over the days. For two-dimensional measurements the assembled system proved to be promising, since in dose deposition measurements with the depth for several beam energies, the penetration of the radiation was increased with the increase of the beam energy and the penumbra measurements of a narrow beam with 2mmPb presented a value of 1.79 cm, considering the type of generator tube and narrow used. Throughout the characterization carried out the dosimetric system proved to be applicable for dosimetry, if operated considering the characteristics presented.

No description available.

A method is set forth which makes use of a commercially available, non-metric, solid-state matrix camera to capture spatial and spectral data from an individual tree bole that can be used to measure characteristics about the stem. In this study diameters and heights were measured and used to estimate the volume of 20 red oak (Quercus spp.) stems ranging in diameter at breast height from 16 to over 60 cm and height from 12 to 20 meters. Images were taken from four orthogonal directions around the each stem. Diameter estimates from matching camera to stem distances (3 to 15 meters) of opposite sides were arithmetically averaged. Two arithmetic averages from perpendicular directions were then geometrically averaged. It was found that locating the camera farther from the tree led to more consistent results over the entire stem while locating it closer to the tree provided the most precise estimates provided the inclination angle did not exceed 45 degrees. This method resulted in geometric mean diameter estimates within ± 4 cm for all heights combined when obtained at a distance of 12 m or greater using a 95 % chi-square maximum anticipated error statistic. Error increases with increased stem height from ± 3 cm to ± 7 cm for heights from 1 to 20 meters. In general, the error is equivalent to 3 times the instrument precision, which varies with distance. Two-thirds of the time volume estimates were within 8 percent, which is quite an improvement over the 30 percent interval afforded by an appropriate volume equation. / Master of Science