103 research outputs found
Anisotropic osmosis filtering for shadow removal in images
We present an anisotropic extension of the isotropic osmosis model that has
been introduced by Weickert et al.~(Weickert, 2013) for visual computing
applications, and we adapt it specifically to shadow removal applications. We
show that in the integrable setting, linear anisotropic osmosis minimises an
energy that involves a suitable quadratic form which models local directional
structures. In our shadow removal applications we estimate the local structure
via a modified tensor voting approach (Moreno, 2012) and use this information
within an anisotropic diffusion inpainting that resembles edge-enhancing
anisotropic diffusion inpainting (Weickert, 2006, Gali\'c, 2008). Our numerical
scheme combines the nonnegativity preserving stencil of Fehrenbach and Mirebeau
(Fehrenbach, 2014) with an exact time stepping based on highly accurate
polynomial approximations of the matrix exponential. The resulting anisotropic
model is tested on several synthetic and natural images corrupted by constant
shadows. We show that it outperforms isotropic osmosis, since it does not
suffer from blurring artefacts at the shadow boundaries
Alternating Direction Implicit (ADI) schemes for a PDE-based image osmosis model
We consider \emph{Alternating Direction Implicit} (ADI) splitting schemes to
compute efficiently the numerical solution of the PDE osmosis model considered
by Weickert et al. for several imaging applications. The discretised scheme is
shown to preserve analogous properties to the continuous model. The dimensional
splitting strategy traduces numerically into the solution of simple tridiagonal
systems for which standard matrix factorisation techniques can be used to
improve upon the performance of classical implicit methods, even for large time
steps. Applications to the shadow removal problem are presented
Manejo de pomares de macieira sob diferentes cores de tela antigranizo: avaliação da qualidade pós-colheita.
A macieira (Malus domestica) Ă© cultivada em regiões de altitude, onde a ocorrĂŞncia de granizo Ă© elevada, o que causa grandes prejuĂzos aos pomares. O objetivo desse trabalho foi avaliar a qualidade de maçãs ?Fuji Suprema? produzidas sob diferentes telas antigranizo
Sistema Web para Análise de Solos
Neste artigo apresenta o desenvolvimento de um sistema de análise de solos realizado por dezenove alunos de um curso tĂ©cnico em informática para internet. Na ocasiĂŁo, cada aluno desempenhou um papel, simulando cargos e funções de uma empresa de software. O sistema desenvolvido visa registrar as etapas realizadas para uma análise quĂmica de solos
InfluĂŞncia do nĂşmero de perfilhos do ano na produtividade da pupunha para palmito.
Espécie nativa da Amazônia, a pupunha apresenta, como vantagem em relação às outras espécies produtoras de palmito, o perfilhamento. A partir do segundo corte do palmito, a ocorrência de perfilhamento com mais de um perfilho apto ao corte por touceira acarreta o aumento de produção e os perfilhos da touceira garantem a longevidade da plantação
POTENCIAL DENDROENERGÉTICO DE COMBUSTÍVEIS SÓLIDOS DE EUCALYPTUS GRANDIS
A utilização de combustĂveis fĂłsseis ainda Ă© o grande pilar de sustentação da atual matriz energĂ©tica mundial, porĂ©m devido a questões ambientais relacionadas ao efeito estufa, emissões de CO2 e mudanças climáticas, juntamente aos impasses econĂ´micos associados aos preços do petrĂłleo, tais combustĂveis vĂŞm sendo substituĂdos por demais fontes de energias renováveis, onde pellets e materiais carbonizados de biomassa sĂŁo vistos como alternativas para a geração de energia. A peletização consiste em comprimir a matĂ©ria-prima, onde a lignina serve como aglutinante e a carbonização ocorre em atmosfera inerte, havendo degradação parcial da matĂ©ria. Assim sendo, o presente trabalho objetivou análises de pellets de eucalipto e dos mesmos carbonizados analisando os teores de: umidade, carbono, voláteis e cinzas, de ambos os materiais, comparando suas propriedades e afirmando o poder dendrocombustĂvel. ApĂłs a carbonização o teor de carbono do material teve um aumento de quatro vezes, com redução de voláteis e umidade, o que Ă© vantajoso para o processo de combustĂŁo e geração de energia tĂ©rmica
Haemoglobin mass and running time trial performance after recombinant human erythropoietin administration in trained men
<p>Recombinant human erythropoietin (rHuEpo) increases haemoglobin mass (Hbmass) and maximal oxygen uptake (vË™ O2 max).</p>
<p>Purpose: This study defined the time course of changes in Hbmass, vË™ O2 max as well as running time trial performance
following 4 weeks of rHuEpo administration to determine whether the laboratory observations would translate into actual
improvements in running performance in the field.</p>
<p>Methods: 19 trained men received rHuEpo injections of 50 IUNkg21 body mass every two days for 4 weeks. Hbmass was
determined weekly using the optimized carbon monoxide rebreathing method until 4 weeks after administration. vË™ O2 max
and 3,000 m time trial performance were measured pre, post administration and at the end of the study.</p>
<p>Results: Relative to baseline, running performance significantly improved by ,6% after administration (10:3061:07 min:sec
vs. 11:0861:15 min:sec, p,0.001) and remained significantly enhanced by ,3% 4 weeks after administration
(10:4661:13 min:sec, p,0.001), while vË™ O2 max was also significantly increased post administration
(60.765.8 mLNmin21Nkg21 vs. 56.066.2 mLNmin21Nkg21, p,0.001) and remained significantly increased 4 weeks after
rHuEpo (58.065.6 mLNmin21Nkg21, p = 0.021). Hbmass was significantly increased at the end of administration compared to
baseline (15.261.5 gNkg21 vs. 12.761.2 gNkg21, p,0.001). The rate of decrease in Hbmass toward baseline values post
rHuEpo was similar to that of the increase during administration (20.53 gNkg21Nwk21, 95% confidence interval (CI) (20.68,
20.38) vs. 0.54 gNkg21Nwk21, CI (0.46, 0.63)) but Hbmass was still significantly elevated 4 weeks after administration
compared to baseline (13.761.1 gNkg21, p<0.001).</p>
<p>Conclusion: Running performance was improved following 4 weeks of rHuEpo and remained elevated 4 weeks after
administration compared to baseline. These field performance effects coincided with rHuEpo-induced elevated vË™ O2 max and
Hbmass.</p>
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