Os sistemas de integração lavoura-pecuária-floresta têm se apresentado promissores, e são apontados como alternativas mais sustentáveis de uso da terra, assim como ferramentas para mitigar as emissões de gases de efeito estufa e diminuir os efeitos que as mudanças climáticas possam gerar na produção agropecuária. Contudo, devido à complexidade desses sistemas, existem ainda muitas limitações técnicas que dificultam a otimização da produção de forragem. O componente arbóreo reduz a quantidade e qualidade da luz, modificando o microclima, e interferindo em processos morfofisiológicos das plantas essenciais para produção de biomassa. Visando entender essas modificações e gerar informações sobre acumulo de biomassa de plantas forrageiras e produção animal em ambientes sombreados, o objetivo geral com este estudo foi avaliar as alterações no microclima do sub-bosque florestal e seus efeitos sobre a produção de forragem, o desempenho animal, e as características morfofisiológicas e estruturais de gramíneas tropicais em diferentes arranjos florestais de sistemas ILPF.. A Brachiaria brizantha cv. Piatã avaliada em dois sistemas de integração lavoura-pecuária-floresta, com espaçamento entre linhas simples de árvores de eucalipto de 14 m (ILPF14) e de 22 m (ILPF22), comparados a um sistema de integração lavoura-pecuária (ILP, a pleno sol), com estratégia de rotação de culturas de 4 anos, sendo 1 ano de lavoura e 3 de pasto. O delineamento experimental foi de blocos casualizados, em esquema de faixas subdivididas, com 4 repetições. Avaliou-se a produção de forragem e o desempenho novilhas nelore, durante 2 ciclo de rotação, no período de 2009 a 2016, comparando as estações de cada ano. No último ano do segundo ciclo, no período de julho de 2015 a junho de 2016, com as árvores adultas e sombreamento intenso, foram realizadas avaliações das respostas morfofisiológicas e estruturais do capim-piatã, no sub-bosque florestal, conforme a distancia das árvores, e estações do ano. / The crop-livestock-forest integrated systems have been pointed out as sustainable alternatives to land use, as well as a tool to mitigate greenhouse gases emissions and to reduce the effects that climate change can generate on agricultural production. However, due the complexity of these systems, there are still many technical limitations that hamper the optimization of forage production. The arboreal component reduces the quantity and quality of light, and modifies the microclimate, interfering in morphophysiological processes essential for biomass accumulation in forage species. The objective of this study was to evaluate the shading effect of different densities of trees on microclimate, and how their interactions influence physiological and structural characteristics of forage plants, and forage production, along the seasons andcrop rotation cycle. Brachiaria brizantha cv. Piatã was evaluated in two crop-livestock-forest integration systems, with single lines of eucalyptus trees spacing by 14 m (ILPF14) and 22 m (ILPF22) (ILPF22), compared to a crop-livestock integration system (ILP; sun), with a crop rotation strategy of 4 years, with 1 year of crop cultivation and 3 years of pasture. A randomized complete blocks design, arranged in a split strips scheme, with 4 replicates was adopted. The forage production and performance of nellore heifers were evaluated during 2 rotation cycles between 2009 and 2016, comparing the seasons of each year. In the last year of the second cycle, from July 2015 to June 2016, with adult trees and intense shading, evaluations of the morphophysiological and structural responses of the piatã palisadegrass were carried out in the sub-forest, according to the distance of the trees, and seasons of the year.

L’agrivoltaïque, association sur une même surface d’une production agricole et d’une production d’énergie d’origine photovoltaïque, apparait aujourd’hui comme une solution innovante pour atténuer les effets du changement climatique, notamment sur le secteur agricole. Déjà imaginé en 1982, les premières expérimentations débutées à Montpellier (France) en 2010 ont montré la pertinence de cette association à travers un maintien des rendements sous certaines conditions, une meilleure efficience d’utilisation du sol ainsi qu’une diminution de la consommation en eau des cultures sous ombrage. Suite à ces travaux pionniers réalisés sous des panneaux photovoltaïques à inclinaison fixe, l’utilisation de panneaux dynamiques à inclinaison variable est apparue nécessaire pour réduire l’hétérogénéité du rayonnement disponible pour la culture mais aussi, adapter la stratégie d’ombrage aux besoins radiatifs de la culture au cours de son développement.La présente thèse avait pour objectif de caractériser et de modéliser l’impact de la présence de panneaux solaires sur le bilan hydrique d’une culture conduite sous dispositif agrivoltaïque dynamique en vue d’optimiser la stratégie d’irrigation et le pilotage de l’inclinaison des panneaux. Les expérimentations menées sur une culture de laitues ont mis en évidence l’intérêt de panneaux dynamiques afin de réduire les hétérogénéités radiatives. Le développement d’un modèle de redistribution des pluies par les panneaux photovoltaïques a permis la mise en œuvre d’une stratégie de pilotage de l’inclinaison en temps réel a permis d’homogénéiser les cumuls observés au sol. L’adaptation d’un modèle de bilan hydrique et de développement de culture par l’ajout d’un module décrivant la dynamique stomatique sous ombrage fluctuant a permis de décrire la consommation en eau de la culture et son développement sous différentes stratégies de pilotage de l’ombrage. Enfin, différentes stratégies de pilotage de l’inclinaison des panneaux photovoltaïque ont pu être simulées et évaluées à l’aide d’un indicateur globale intégrant l’efficience d’utilisation du sol, la productivité de l’eau, le décalage de maturité et les sources d’hétérogénéités pouvant affecter la production de laitues. / Agrivoltaism, defined as the association on the same land of agricultural and photovoltaic energy production, appears as an innovating concept to dampen some of the effects of climate change, in the agricultural sector. Although the concept was already imagined in 1982, the first experimentations started in 2010 at Montpellier (France) and showed the relevance of this combination by the maintenance of crop yield under certain conditions, the increase of land use efficiency and a reduction of water consumption for the tested crops. Following this pioneering work done under fixed (but not horizontal) photovoltaic panels, the use of "dynamic" panels, i.e. panels with a variable tilting angle, appears necessary to reduce the spatial heterogeneity of the transmitted radiation but also to adapt the shading strategy to the radiation amount required for crop growth.This thesis aims to characterize and to model the impact of the photovoltaic panels on the water budget of the cultivated plot and to progress towards the optimization of irrigation strategies in such systems controlled by the variations in time of the tilting angle of the panels. Experimentations conduced on lettuces showed the benefits of "dynamic" photovoltaic panels to reduce the radiative heterogeneity. Accounting for rain redistribution by the solar panels permits the implementation of a real time strategy to reduce rainfall heterogeneity on the ground surface. The derivation of a water budget and crop development model which describes the dynamics of stomatal conductance under fluctuating shading allows a better simulation of water consumption and crop development for different shading strategies. Finally, various strategies for the piloting of the solar panels could be tested and evaluated by a new, global index combining land use efficiency, water productivity, maturity delays and heterogeneities (in rain and radiation) which can impact production.

3D human face reconstruction has been an extensive research for decades due to its wide applications, such as animation, recognition and 3D-driven appearance synthesis. Although commodity depth sensors are widely available in recent years, image based face reconstruction are significantly valuable as images are much easier to access and store. In this dissertation, we first propose three image-based face reconstruction approaches according to different assumption of inputs. In the first approach, face geometry is extracted from multiple key frames of a video sequence with different head poses. The camera should be calibrated under this assumption. As the first approach is limited to videos, we propose the second approach then focus on single image. This approach also improves the geometry by adding fine grains using shading cue. We proposed a novel albedo estimation and linear optimization algorithm in this approach. In the third approach, we further loose the constraint of the input image to arbitrary in the wild images. Our proposed approach can robustly reconstruct high quality model even with extreme expressions and large poses. We then explore the applicability of our face reconstructions on four interesting applications: video face beautification, generating personalized facial blendshape from image sequences, face video stylizing and video face replacement. We demonstrate great potentials of our reconstruction approaches on these real-world applications. In particular, with the recent surge of interests in VR/AR, it is increasingly common to see people wearing head-mounted displays. However, the large occlusion on face is a big obstacle for people to communicate in a face-to-face manner. Our another application is that we explore hardware/software solutions for synthesizing the face image with presence of HMDs. We design two setups (experimental and mobile) which integrate two near IR cameras and one color camera to solve this problem. With our algorithm and prototype, we can achieve photo-realistic results. We further propose a deep neutral network to solve the HMD removal problem considering it as a face inpainting problem. This approach doesn't need special hardware and run in real-time with satisfying results.

<p>Human viewers are extremely sensitive to the appearanceof peoples faces, which makes the rendering of realistic human faces a challenging problem. Techniques for doing this have continuously been invented and evolved since more than thirty years. </p><p>This thesis makes use of recent methods within the area of image based rendering, namely the acquisition of reflectance fields from human faces. The reflectance fields are used to synthesize and realistically render models of human faces. </p><p>A shape from shading technique, assuming that human skin adheres to the Phong model, has been used to estimate surface normals. Belief propagation in graphs has then been used to enforce integrability before reconstructing the surfaces. Finally, the additivity of light has been used to realistically render the models. </p><p>The resulting models closely resemble the subjects from which they were created, and can realistically be rendered from novel directions in any illumination environment.</p>

Comprendre, analyser et modéliser l'environment 3D à partir d'images provenant de caméras et d'appareils photos est l'un des défis majeurs actuel de recherche en vision par ordinateur. Cette thèse s'interesse à plusieurs aspects géométriques et photometriques liés à la reconstruction de surface à partir de plusieurs caméras calibrées. La reconstruction 3D est vue comme un problème de rendu inverse, et vise à minimiser une fonctionnelle d'énergie afin d'optimiser un maillage triangulaire représentant la surface à reconstruire. L'énergie est définie via un modèle génératif faisant naturellement apparaître des attributs tels que la visibilité ou la photométrie. Ainsi, l'approche présentée peut indifférement s'adapter à divers cas d'application tels que la stéréovision multi-vues, la stéréo photométrique multi-vues ou encore le "shape from shading" multi-vues. Plusieurs approches sont proposées afin de résoudre les problèmes de correspondances de l'apparence pour des scènes non Lambertiennes, dont l'apparence varie en fonction du point de vue. La segmentation, la stéréo photométrique ou encore la réciprocité d'Helmholtz sont des éléments étudiés afin de contraindre la reconstruction. L'exploitation de ces contraintes dans le cadre de reconstruction multi-vues permet de reconstruire des modèles complets 3D avec une meilleure qualité.

Human viewers are extremely sensitive to the appearanceof peoples faces, which makes the rendering of realistic human faces a challenging problem. Techniques for doing this have continuously been invented and evolved since more than thirty years. This thesis makes use of recent methods within the area of image based rendering, namely the acquisition of reflectance fields from human faces. The reflectance fields are used to synthesize and realistically render models of human faces. A shape from shading technique, assuming that human skin adheres to the Phong model, has been used to estimate surface normals. Belief propagation in graphs has then been used to enforce integrability before reconstructing the surfaces. Finally, the additivity of light has been used to realistically render the models. The resulting models closely resemble the subjects from which they were created, and can realistically be rendered from novel directions in any illumination environment.

In the fight to reduce carbon emissions, it is easy to see the necessity of reducing energy consumption. Buildings consume a large amount of energy, and have significant potential for energy savings. One tool for realising these potential savings is building simulation. To be able to use building simulation, accurate models for windows are needed. The models include individual layer models, to determine the solar and longwave radiative behaviours, as well as whole-system models to determine heat flows through the various layers of fenestration systems. This thesis looks at both kinds of models for incorporating windows into building simulations. A new network whole-system model is implemented, and integrated into the California Simulation Engine building simulation software. This model is also used as the calculation engine for a stand-alone rating tool. Additionally, a measurement technique used to measure off-normal solar properties of drapery materials, as part of developing shading layer models, is investigated using a Monte Carlo simulation. The network model uses a very general resistance network, allowing heat transfer between any two layers in a complex fenestration system (CFS), whether they are adjacent or not, between any layer and the indoor or outdoor side, or between the indoor and outdoor sides, although this last case is unlikely. Convective and radiative heat transfer are treated using the same format, resulting in increased stability. This general resistance network is used to calculate indices of merit for the CFS using numerical experiments. This approach requires fewer iterations to solve than previous solution methods, and is more flexible. The off-normal measurement technique which was investigated used a sample holder inserted into an integrating sphere. This is a non-standard way of using an integrating sphere, and early analyses did not provide conclusive information as to the effect of the sample holder. A Monte Carlo analysis confirmed the amount of beam attenuation as being 20% for the sample holder used in the experiments. Also con firmed was the effectiveness of dual-beam integrating spheres in correcting for the presence of a sample holder. The stand-alone rating tool which uses the general network framework, incorporates an easy-to-use visual interface. This tool models multiple types of shading layers with no restrictions on how they are combined. Users can easily change any one layer to see the effects of different arrangements. Users may specify any combination of indoor and outdoor ambient and mean radiant temperatures, insolation, and beam/diffuse split.

Achieving acceptable plane wave uniformity throughout an expanded volume is necessary to conduct scattering measurements on a large target in a controlled environment. An expanded volume is large relative to the size of the nearfield array configuration used to produce plane wave uniformity. The optimum set of shading coefficients for a nearfield array may not produce acceptable plane wave uniformity as the volume and frequency domain are expanded for a given array configuration. Choosing the frequency domain as a single frequency for an optimum set of coefficients will produce plane wave uniformity throughout the largest possible volume for a given array configuration. This study determines the acceptability of uniformity results produced by an optimum set of frequency dependent coefficients throughout an expanded volume for two array configurations that comprise a system for measuring bistatic target strength in the nearfield. Minimizing the frequency domain chosen for an optimum set of coefficients will produce plane wave uniformity for the largest possible volume for a given array configuration. This study determines the acceptability of uniformity results produced by an optimum set of frequency dependent coefficients throughout an optimistic volume for two array configurations that comprise a bi-static array.

Four studies including ten experiments adresses interrelations between some major and classical issues in visual perception: 3-D perception, colour constancy, colour perception and colour vision deficiencies. The main experimental paradigm to investigate the issues is within that of simulated shape from shading. 3-D impressions are induced by projecting space-modulated illuminations onto flat surfaces (displays), varying the colours and layout of the displays and the colour and modulation of the illumination. Study I includes four experiments investigating three types of space- modulated illumination. All experiments confirmed earlier findings that chromatic colour and complex display layout with reflectance edges crossed by illumination edges enhances shape from shading. In Study II the impressions of shape from shading and real 3-D objects were compared between persons with deutan colour vision deficiencies and normals. As predicted, the deutans show fewer and less distinct 3-D impressions in situations with their specific "problem colours" red and green. They also show a generally lower tendency for 3-D impressions, interpreted as a generally weaker colour constancy. Study III presents the AMBEGUJAS phenomenon; a novel twofold ambiguous shape from shading situation, continuously alternating between two different 3-D impressions coupled with different colour attributions. One solution is of an object with two clear surface colours, the other one of an object with greyish (desaturated) colours in coloured illumination which means classical colour constancy. The phenomenon illustrates the visual processes of separating reflectance and illumination characteristics and may provide a useful experimental setting to study colour constancy. In Study IV the AMBEGUJAS phenomenon is found to be robust as to chromaticness and different luminance contrasts for both normals and deutans. However, the deutans show slower shifts between percepts and a less pronounced desaturation of colour, which indicates a weaker colour constancy. The studies add evidence to the contribution of colour to 3-D shape perception, validated in a novel way by the results on "colour-blinds". The AMBEGUJAS phenomenon provides further support that the factors affecting shape from shading and the deutans different impressions are to be understood with reference to colour constancy. The deutans different impressions compared to normals are remarkable per se, but probably with very limited implications to everyday life. / <p>Diss. (sammanfattning) Umeå : Umeå university, 1996, härtill 4 uppsatser</p> / digitalisering@umu

This paper describes the `strucplot' framework for the visualization of multi-way contingency tables. Strucplot displays include hierarchical conditional plots such as mosaic, association, and sieve plots, and can be combined into more complex, specialized plots for visualizing conditional independence, GLMs, and the results of independence tests. The framework's modular design allows flexible customization of the plots' graphical appearance, including shading, labeling, spacing, and legend, by means of graphical appearance control (`grapcon') functions. The framework is provided by the R package vcd. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics