Reconsidering light transport : acquisition and display of real-world reflectance and geometry

In this thesis, we cover three scenarios that violate common simplifying assumptions about the nature of light transport. We begin with the first ingredient to any çD rendering: a geometry model. Most çD scanners require the object-of-interest to show diffuse refectance. The further a material deviates from the Lambertian model, the more likely these setups are to produce corrupted results. By placing a traditional laser scanning setup in a participating (in particular, fuorescent) medium, we have built a light sheet scanner that delivers robust results for a wide range of materials, including glass. Further investigating the phenomenon of fluorescence, we notice that, despite its ubiquity, it has received moderate attention in computer graphics. In particular, to date no datadriven reflectance models of fluorescent materials have been available. To describe the wavelength-shifling reflectance of fluorescent materials, we define the bispectral bidirectional reflectance and reradiation distribution function (BRRDF), for which we introduce an image-based measurement setup as well as an efficient acquisition scheme. Finally, we envision a computer display that showsmaterials instead of colours, and present a prototypical device that can exhibit anisotropic reflectance distributions similar to common models in computer graphics.In der Computergraphik und Computervision ist es unerlässlich, vereinfachende Annahmen über die Ausbreitung von Licht zumachen. In dieser Dissertation stellen wir drei Fälle vor, in denen diese nicht zutreffen. So wird die dreidimensionale Geometrie von Gegenständen oft mit Hilfe von Laserscannern vermessen und dabei davon ausgegangen, dass ihre Oberfläche diffus reflektiert. Dies ist bei den meisten Materialien jedoch nicht gegeben, so dass die Ergebnisse oft fehlerhaft sind. Indem wir das Objekt in einem fluoreszierenden Medium einbetten, kann ein klassischer CD-Scanner-Aufbau so modifiziert werden, dass er verlässliche Geometriedaten für Objekte aus verschiedensten Materialien liefert, einschließlich Glas. Auch die akkurate Nachbildung des Aussehens von Materialien ist wichtig für die photorealistische Bildsynthese. Wieder interessieren wir uns für Fluoreszenz, diesmal allerdings für ihr charakteristisches Erscheinungsbild, das in der Computergraphik bislang kaum Beachtung gefunden hat. Wir stellen einen bildbasierten Aufbau vor, mit dem die winkel- und wellenlängenabhängige Reflektanz fluoreszierender Oberflächen ausgemessen werden kann, und eine Strategie, um solche Messungen effizient abzuwickeln. Schließlich befassen wir uns mit der Idee, nicht nur Farben dynamisch anzuzeigen, sondern auch Materialien und ihr je nach Lichteinfall und Blickwinkel unterschiedliches Aussehen. Einer generellen Beschreibung des Problems folgt die konkrete Umsetzung in Formzweier Prototypen, die verschiedene Reflektanzverteilungen auf einer Oberfläche darstellen können

Aeronautics and space report of the President, 1980 activities

The year's achievements in the areas of communication, Earth resources, environment, space sciences, transportation, and space energy are summarized and current and planned activities in these areas at the various departments and agencies of the Federal Government are summarized. Tables show U.S. and world spacecraft records, spacecraft launchings for 1980, and scientific payload anf probes launched 1975-1980. Budget data are included

NASA Tech Briefs, October 2000

Topics include: special coverage sections on CAD, CAE, and PDM, and, Composites and Plastics, and sections on electronic components and systems, software, test and measurement, mechanics, manufacturing/fabrication, physical sciences, information sciences, book and reports, and special sections of Electronics Tech Briefs and Motion Control Tech Brief

Innovative contributions on calibration methodologies towards reliable microflow measurements

Flow measurement is critical in healthcare, chemistry and pharmaceutics, to mention a few. In fact, there are several applications in the microflow and nanoflow range, such as scaled-down process technology, drug development, and special health-care applications, as organ-on-a- chip technology. Nevertheless, the majority of the instruments used for the specified applica- tions are not sufficiently studied regarding their flow accuracy and traceability. Hence these fluid applications at the micro and nanoscale still lack well defined calibration methodologies for the devices working at the mentioned flow range with adequate uncertainty values. The work presented in this thesis focuses on the development and improvement of in- novative applications of calibration methodologies for microflow measuring instruments. The gravimetric method already implemented at IPQ from 120 L/h to 2000 mL/h was used and improved for low flow rates down to 10 L/h. Additionally, other 4 methods were developed to enable the calibration of micro/nano flows in a non-intrusive way. They are interferometry, pending drop, front track and comparison method (where a calibrated flow generator is used as the reference standard). The methodology that is best suited for each specific instrument and each measurement range, with the lowest uncertainty, was successfully identified along with the relevant influence factors in microflow measurements. A specific objective of this work was to increase the measuring range of IPQ-LVC down to 5 nL/min (0.3 L/h) with a 3% target uncertainty (k=2). This objective was possible to achieve and even surpass with the use of the interferometric method, where measurements were per- formed down to 1.6 nL/min (0.1 L/h) with 2 % uncertainty(k=2). This method was internally validated by comparison with the gravimetric method and is now in the process of external validation by EURAMET project 1508.A medição de caudal é extremamente importante em áreas como a saúde, a indústria química ou farmacêutica. Caudais à escala micro/nanométrica são já utilizados em várias aplicações, nomeadamente, processos tecnológicos de redução de escala, desenvolvimento de fármacos e especialmente em novas aplicações na área da saúde, tais como a tecnologia de órgãos-em- chip. Os sistemas de medição utilizados nas aplicações indicadas, por serem relativamente recentes, não estão ainda suficientemente estudados quanto a sua exatidão e rastreabilidade. É, assim, necessário desenvolver metodologias de calibração específicas para os referidos cau- dais com incertezas de medição adequadas. Este trabalho irá focar-se no desenvolvimento e melhoramento de metodologias de cali- bração de instrumentos utilizados na medição de micro/nanocaudal de fluidos. O método gra- vimétrico já implementado no IPQ numa gama de medição de 120 L/h a 2000 mL/h foi me- lhorado de forma se realizarem calibrações até 10 L/h. Foram ainda desenvolvidos 4 novos métodos, a interferometria, o método da gota pendente, o método do deslocamento de me- nisco e o método comparativo (onde um gerador de caudal é utilizado como referência). A metodologia que melhor se aplica a cada instrumento e a gama de medição, com a melhor incerteza foi identificada, assim como fatores de influência na medição de microcaudal. Um objetivo específico deste trabalho foi aumentar o intervalo de medição do IPQ-LVC para 5 nL/min (0.3 L/h) com uma incerteza de (k=2). Isso foi possível e até ultrapassável com a utilização do método interferométrico, em que as foram realizadas medições até 1.6 nL/min (0.1 L/h) com 2% de incerteza (k=2). Este método foi validado internamente por comparação com o método gravimétrico e está agora em processo de validação externa através do projeto EURAMET 1508

Index to 1986 NASA Tech Briefs, volume 11, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1986 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

NASA Tech Briefs, February 1997

Topics include: Test and Measurement; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Report

Optical In-Process Measurement Systems

Information is key, which means that measurements are key. For this reason, this book provides unique insight into state-of-the-art research works regarding optical measurement systems. Optical systems are fast and precise, and the ongoing challenge is to enable optical principles for in-process measurements. Presented within this book is a selection of promising optical measurement approaches for real-world applications

Portuguese SKA white book

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Special Issue of the Manufacturing Engineering Society (MES)

This book derives from the Special Issue of the Manufacturing Engineering Society (MES) that was launched as a Special Issue of the journal Materials. The 48 contributions, published in this book, explore the evolution of traditional manufacturing models toward the new requirements of the Manufacturing Industry 4.0 and present cutting-edge advances in the field of Manufacturing Engineering focusing on additive manufacturing and 3D printing, advances and innovations in manufacturing processes, sustainable and green manufacturing, manufacturing systems (machines, equipment and tooling), metrology and quality in manufacturing, Industry 4.0, product lifecycle management (PLM) technologies, and production planning and risks