Refractive Index Dependent Bidirectional Scattering Distribution Functions

Wir untersuchen die Wirkung des Eintauchens von realen Materialien in Medien mit unterschiedlichem Brechindex. In der Theorie sollte das Reflektanz-Verhalten eines Materials, das in den umgebenden Medien mit unterschiedlichen Brechungsindizes eingetaucht wird,durch die Fresnel-Gleichungen vorhergesagt werden. Wie wir jedoch zeigen, folgt nur eine Unterklasse von Materialien diesem theoretischen Modell. In der Realität zeigen viele Materialien unerwartete Effekte wie stärker lokalisierte Highlights oder eine deutliche Zunahme von spekularer Reflexion durch Mikrogeometrie. In unseren Experimenten haben wir herausgefunden, dass diese Effekte ziemlich stark variieren, und keines der bestehenden BRDF-Modelle das realistisch wiedergeben. Wir schlagen ein neues, parametrisches Modell vor, dass den Brechungsindex berücksichtigt. Wir fitten unsere Messergebnisse an das Modell und erhalten so Parameter zur Beschreibung der Reflektanz verschiedener Medien.We investigate the effect of immersing real-world materials into media of different refractive indices. In theory, the reflective and transmissive behavior of a material that is immersed into surrounding media with different refractive indices should be predicted by the Fresnel equations. However, as we show, %\todo{Ivo}{} only a subclass of materials follows this theoretical model. In reality, many materials exhibit unexpected effects such as stronger localized highlights or a significant increase in the glossy reflection due to microgeometry. In our experiments we found that the variation of these effects can be quite strong, and none of the existing BRDF models realistically reproduce these effects seen in reality. We propose a new, parametric model that takes refractive index changes into account. We fit measurements of different materials and present results to demonstrate the importance of BRDF changes for submerged objects

Biomass energy potential of forest harvest residue in Northwestern Ontario

Woody biomass contributes less than 6% of total energy production in Canada. Based on previous data relating to the supply, quality and economic potential, this compilation of relevant data provides an estimation on the available sustainable supply of woody biomass in Northwestern Ontario. This thesis explores the availability and thermal potential of biomass in the form of forest harvest residue and underutilized tree species in Northwestern Ontario and the potential for increased energy production at various existing facilities in the region. This study summarizes previously published data on availability, quality and economic feasibility of biomass acquisition in the region. It was estimated that there is 40.2m3/ha of available woody biomass feedstock throughout the study area, with an average thermal potential of 20.65 Mj/kg to 21.28 Mj/kg. These results indicate a sufficient supply with adequate thermal potential is readily available in the region. The total cost of procurement of biomass in the region averages 44- 46$/gt, which indicates an economically feasible scale based on the technically available biomass. Summaries provided in this study quantify objective data on these objectives to determine the feasibility of increased biomass energy production in the region

Appearance-design interfaces and tools for computer cinematography: Evaluation and application

We define appearance design as the creation and editing of scene content such as lighting and surface materials in computer graphics. The appearance design process takes a significant amount of time relative to other production tasks and poses difficult artistic challenges. Many user interfaces have been proposed to make appearance design faster, easier, and more expressive, but no formal validation of these interfaces had been published prior to our body of work. With a focus on novice users, we present a series of investigations into the strengths and weaknesses of various appearance design user interfaces. In particular, we develop an experimental methodology for the evaluation of representative user interface paradigms in the areas of lighting and material design. We conduct three user studies having subjects perform design tasks under controlled conditions. In these studies, we discover new insight into the effectiveness of each paradigm for novices measured by objective performance as well as subjective feedback. We also offer observations on common workflow and capabilities of novice users in these domains. We use the results of our lighting study to develop a new representation for artistic control of lighting, where light travels along nonlinear paths

Detection and Localisation Using Light

Visible light communication (VLC) systems have become promising candidates to complement conventional radio frequency (RF) systems due to the increasingly saturated RF spectrum and the potentially high data rates that can be achieved by VLC systems. Furthermore, people detection and counting in an indoor environment has become an emerging and attractive area in the past decade. Many techniques and systems have been developed for counting in public places such as subways, bus stations and supermarkets. The outcome of these techniques can be used for public security, resource allocation and marketing decisions. This thesis presents the first indoor light-based detection and localisation system that builds on concepts from radio detection and ranging (radar) making use of the expected growth in the use and adoption of visible light communication (VLC), which can provide the infrastructure for our light detection and localisation (LiDAL) system. Our system enables active detection, counting and localisation of people, in addition to being fully compatible with existing VLC systems. In order to detect human (targets), LiDAL uses the visible light spectrum. It sends pulses using a VLC transmitter and analyses the reflected signal collected by an optical receiver. Although we examine the use of the visible spectrum here, LiDAL can be used in the infrared spectrum and other parts of the light spectrum. We introduce LiDAL with different transmitter-receiver configurations and optimum detectors considering the fluctuation of the received reflected signal from the target in the presence of Gaussian noise. We design an efficient multiple input multiple output (MIMO) LiDAL system with wide field of view (FOV) single photodetector receiver, and also design a multiple input single output (MISO) LiDAL system with an imaging receiver to eliminate ambiguity in target detection and localisation. We develop models for the human body and its reflections and consider the impact of the colour and texture of the cloth used as well as the impact of target mobility. A number of detection and localisation methods are developed iii for our LiDAL system including cross correlation, a background subtraction method and a background estimation method. These methods are considered to distinguish a mobile target from the ambient reflections due to background obstacles (furniture) in a realistic indoor environment

コンピュータグラフィックスによる木材の質感表現の高度化に関する研究

信州大学(Shinshu university)博士（工学）Thesis桃井　貞美. コンピュータグラフィックスによる木材の質感表現の高度化に関する研究. 信州大学, 2015, 博士論文. 博士（工学）, 甲第639号, 平成27年9月30日授与.doctoral thesi

Abstract Measuring and Modeling the Appearance of Finished Wood

Wood coated with transparent finish has a beautiful and distinctive appearance that is familiar to everyone. Woods with unusual grain patterns, such as tiger, burl, and birdseye figures, have a strikingly unusual directional reflectance that is prized for decorative applications. With new, high resolution measurements of spatially varying BRDFs, we show that this distinctive appearance is due to light scattering that does not conform to the usual notion of anisotropic surface reflection. The behavior can be explained by scattering from the matrix of wood fibers below the surface, resulting in a subsurface highlight that occurs on a cone with an out-of-plane axis. We propose a new shading model component to handle reflection from subsurface fibers, which is combined with the standard diffuse and specular components to make a complete shading model. Rendered results from fits of our model to the measurement data demonstrate that this new model captures the distinctive appearance of wood