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AUTOMATIC IMAGE TO MODEL ALIGNMENT FOR PHOTO-REALISTIC URBAN MODEL RECONSTRUCTIONPartington, Mike 01 January 2001 (has links)
We introduce a hybrid approach in which images of an urban scene are automatically alignedwith a base geometry of the scene to determine model-relative external camera parameters. Thealgorithm takes as input a model of the scene and images with approximate external cameraparameters and aligns the images to the model by extracting the facades from the images andaligning the facades with the model by minimizing over a multivariate objective function. Theresulting image-pose pairs can be used to render photo-realistic views of the model via texturemapping.Several natural extensions to the base hybrid reconstruction technique are also introduced. Theseextensions, which include vanishing point based calibration refinement and video stream basedreconstruction, increase the accuracy of the base algorithm, reduce the amount of data that mustbe provided by the user as input to the algorithm, and provide a mechanism for automaticallycalibrating a large set of images for post processing steps such as automatic model enhancementand fly-through model visualization.Traditionally, photo-realistic urban reconstruction has been approached from purely image-basedor model-based approaches. Recently, research has been conducted on hybrid approaches, whichcombine the use of images and models. Such approaches typically require user assistance forcamera calibration. Our approach is an improvement over these methods because it does notrequire user assistance for camera calibration.
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Comportamento reológico e propriedades termofísicas da polpa de goiaba. / Rheological behavior and thermophysical properties of guava pulp.PEREIRA, Nélio José Lira. 04 July 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-07-04T14:51:20Z
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Previous issue date: 2011-09 / Foram determinadas as propriedades reológicas e termofísicas de polpas de goiaba
cv. Paluma, nas concentrações de 8, 10 e 12 °Brix. As amostras foram previamente
caracterizadas quanto às características químicas, físicas e físico-químicas. As medidas
viscométricas foram realizadas fazendo-se uso de um viscosímetro Brookfíeld, obtendo-se, desta forma dados de viscosidade aparente, torque, tensão de cisalhamento e taxa de
deformação, nas temperaturas de 10, 20, 30, 40 e 50 °C. As propriedades termofísicas
massa específica, foi determinada pelo método picnométrico; o calor específico pelo
método das misturas e a difusividade térmica pelo método do cilindro infinito. A
condutividade térmica foi obtida pela relação com a massa específica, calor específico e
difusividade térmica, obtidos experimentalmente. Os modelos da Lei da Potência, Casson,
Herschel-Bulkley e Mizrahi & Berk foram ajustados aos dados de tensão de cisalhamento
em função da taxa de deformação. As propriedades termofísicas também foram estimadas
por meio de equações propostas em literatura cujos resultados foram comparados com os
resultados experimentais. As polpas de goiaba se caracterizaram como ácidas,
apresentaram comportamento pseudoplástico e as viscosidades aparentes foram
influenciadas pela temperatura e seguiram uma relação do tipo Arrhenius. O calor
específico foi reduzido com o aumento da concentração; a massa específica aumentou,
seguindo relação direta com a concentração e inversa, com a temperatura, e foi bem
estimada por meio de equações. A condutividade térmica calculada por equações propostas em literatura não resultou em estimativas aceitáveis. / The rheological and thermophysical properties of guava cv. Paluna pulp were
determined at concentrations of 8, 10 and 12 °Brix, and temperatures between 10 and 50
°C. The samples, previously characterized with respect to chemical and physical properties,
were submitted to viscometric measures, using a Brookfield RVT viscometer to obtain data
on viscosity, torque, shear stress and shear rate. Shear stress and shear rate data were fit to
the Power Law, Casson, Herschel-Bulkley and Mizrahi & Berk models. Thermophysical
properties and the respective determination methodologies were density using the
pycnometer method, specifíc heat by the method of mixtures, and thermal diffusiveness
using the infinite cylinder method. Thermal conductivity was obtained from the relation
with density, specifíc heat and thermal diffusiveness, obtained experimentally.
Thermophysical properties were also estimated by equations proposed in the literature and
results were compared with experimental results. Guava pulps are characterized as acids
and concentration did not affect color, luminosity, redness or yellowness. Samples
exhibited pseudoplastic behavior, while viscosity was iníluenced by temperature and
followed an Arrhenius-type relation. Specifíc heat was reduced with an increase in
concentration and density, following a direct relation with concentration and inverse with
temperature. Density was estimated by equations at ali concentrations. Thermal
conductivity, calculated by equations proposed in the literature, did not result in acceptable
estimates.
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