Interactive design of complex time-dependent lighting

Visualizing complicated lighting sequences while designing large theatrical productions proves difficult. The author provides some techniques that achieve fast interaction regardless of scene and lighting complexity, even when used with costly rendering algorithms

An Accelerating 3D Image Reconstruction System Based on the Level-of-Detail Algorithm

This paper proposes a research of An Accelerating 3D Image Reconstruction System Based on the Level-of-Detail Algorithm and combines 3D graphic application interfaces, such as DirectX3D and OpenCV to reconstruct the 3D imaging system for Magnetic Resonance Imaging (MRI), and adds Level of Detail (LOD) algorithm to the system. The system uses the volume rendering method to perform 3D reconstruction for brain imaging. The process, which is based on the level of detail algorithm that converts and formulates functions from differing levels of detail and scope, significantly reduces the complexity of required processing and computation, under the premises of maintaining drawing quality. To validate the system's efficiency enhancement on brain imaging reconstruction, this study operates the system on various computer platforms, and uses multiple sets of data to perform rendering and 3D object imaging reconstruction, the results of which are then verified and compared

A 3D Graphical Method for Interactively Determining the Vertical Convexity of Designs to be Molded

The Center for 3D Visualization Hardcopy (C3VH) was initiated in 1995 as a web-accessible facility to create 3D physical models. By making such prototyping hardware easy to access and the geometry files easy to check and correct, we have been able to drive the model-making process into the less traditional manufacturing area of scientific visualization. But, there have been requests for many copies of a single model. As "rapid" prototyping is actually quite slow and unsuitable for mass production, these requests have required us to enter the world of molding for mass production. As part of this, we have needed to quickly determine how feasible it is to mold a particular model. This paper shows an interactive OpenGL method that we developed for determining the optimal orientation for a model's parting line. By using a novel OpenGL stencil buffer technique, the user can reorient the model on the screen, and see from the colors in the display how vertically convex it is in that orientation, and in what parts of the model it is not vertically convex

Entwicklung eines semi-automatischen Workflows zur Ableitung ikonographischer Kartenzeichen

Die Verwendung von ikonographischen, bildhaften Kartenzeichen ist sehr beliebt bei der Darstellung von Sehenswürdigkeiten in touristischen Karten sowie bei Kartendarstellungen für Kinder und Jugendliche. Der Begriff des Non-Photorealistic Rendering (NPR) beschreibt einen zentralen Bereich in der Computergrafik, der sich mit der Erzeugung von Bildern auseinandersetzt, die scheinbar handgemacht sind und bewusst nicht dem physikalisch korrekten Abbild eines Modells entsprechen. Ein weiteres Trendthema zur Nachahmung eines bestimmten Stils eines Kunstwerks stellt der Neural Style Transfer (NST) dar. Hierbei werden künstlerische Bilder durch Trennung und Rekombination von Bildinhalt und Stil erzeugt. Im Rahmen der vorliegenden Arbeit ist ein semi-automatischer Workflow zur Erzeugung ikonographischer Gebäudedarstellungen für die Nutzung in zoombaren Webkarten entwickelt und in drei künstlerischen Stilvarianten unter Nutzung von Bildverarbeitungswerkzeugen in dem rasterbasierten Open Source Bildbearbeitungsprogramm GIMP, speziell mit der Filtersammlung G'MIC technisch umgesetzt worden. Außerdem zeigt die Masterarbeit das Potential der Ableitung von ikonographischen Signaturen durch den Style-Transfer mittels neuronaler Netze.:Selbstständigkeitserklärung III Inhaltsverzeichnis 5 Abbildungsverzeichnis 7 Tabellenverzeichnis 8 Abkürzungsverzeichnis 9 1 Einleitung 10 1.1 Motivation 10 1.2 Gliederung der Arbeit 10 2 Literaturstudium 11 2.1 Computergrafik 11 2.2 Non-Photorealistic Rendering 11 2.3 Neural Style Transfer 14 2.3.1 Einleitung 14 2.3.2 Convolutional Neural Network 15 2.3.3 Beschreibung des Algorithmus 17 3 Methodik 19 3.1 Technische Komponenten 19 3.2 Kriterien der Bildauswahl 19 3.3 Workflow „Ölmalerei“ 21 3.4 Workflow „Tuschezeichnung 22 3.5 Workflow „Silhouette“ 22 4 Praktischer Teil 23 4.1 Konkrete Umsetzung 23 4.1.1 Workflow „Ölmalerei“ 24 4.1.2 Workflow „Tuschezeichnung“ 32 4.1.3 Workflow „Silhouette“ 32 4.2 Implementierung eines Automatisierungsprozesses 35 4.3 Anwendung: Karte Dresden 39 4.4 Neural Style Transfer 43 4.4.1 Online-Anwendungen 43 4.4.2 Offline-Implementierung 45 5 Diskussion 51 5.1 Resultate 51 5.1.1 Bildverarbeitung 51 5.1.2 Neural Style Transfer 51 5.2 Ausblick 52 6 Zusammenfassung 52 Literaturverzeichnis 53The use of iconographic, pictorial map symbols is very popular for the representation of places of interest in tourist maps as well as for map presentations for children and young people. The term Non-Photorealistic Rendering (NPR) describes a prominent field in computer graphics that deals with the generation of images that are apparently handmade and deliberately do not correspond to the physically correct image of a model. Neural Style Transfer (NST) is another trend topic for imitating a certain style of an artwork. Here, artistic images are created by separating and recombining image content and style. In the context of the present work, a semi-automatic workflow for the creation of iconographic building representations for use in zoomable web maps has been developed and technically implemented in three artistic style variants using image processing tools in the raster-based open source image processing program GIMP, especially with the filter collection G'MIC. In addition, the master thesis demonstrates the potential of deriving iconographic signatures through style transfer using neural networks.:Selbstständigkeitserklärung III Inhaltsverzeichnis 5 Abbildungsverzeichnis 7 Tabellenverzeichnis 8 Abkürzungsverzeichnis 9 1 Einleitung 10 1.1 Motivation 10 1.2 Gliederung der Arbeit 10 2 Literaturstudium 11 2.1 Computergrafik 11 2.2 Non-Photorealistic Rendering 11 2.3 Neural Style Transfer 14 2.3.1 Einleitung 14 2.3.2 Convolutional Neural Network 15 2.3.3 Beschreibung des Algorithmus 17 3 Methodik 19 3.1 Technische Komponenten 19 3.2 Kriterien der Bildauswahl 19 3.3 Workflow „Ölmalerei“ 21 3.4 Workflow „Tuschezeichnung 22 3.5 Workflow „Silhouette“ 22 4 Praktischer Teil 23 4.1 Konkrete Umsetzung 23 4.1.1 Workflow „Ölmalerei“ 24 4.1.2 Workflow „Tuschezeichnung“ 32 4.1.3 Workflow „Silhouette“ 32 4.2 Implementierung eines Automatisierungsprozesses 35 4.3 Anwendung: Karte Dresden 39 4.4 Neural Style Transfer 43 4.4.1 Online-Anwendungen 43 4.4.2 Offline-Implementierung 45 5 Diskussion 51 5.1 Resultate 51 5.1.1 Bildverarbeitung 51 5.1.2 Neural Style Transfer 51 5.2 Ausblick 52 6 Zusammenfassung 52 Literaturverzeichnis 5

Dynamic Scalable Network Area of interest management for Virtual Worlds

A major performance challenge in developing a massively multi-user virtual world is network scalability. This is because the network over which entities communicate can quickly develop into a bottleneck. Three critical factors: bandwidth usage, packets per second, and network-related CPU usage, should be governed by the number of entities a given user is interested in, not the total number of entities in the world. The challenge then is to allow a virtual world to scale to any size without an appreciable drop in system performance. To address these concerns, this thesis describes a novel Area of Interest Manager (AOIM) built atop the NPSNET-V virtual environment system. It is a dynamically sized, geographical region based, senderside interest manager that supports dynamic entity discovery and peer-to-peer entity communication. The AOIM also makes use of tools provided by the NPSNET-V system, such as variable resolution protocols and variable data transmission rate. Performance tests have shown conclusively that these interest management techniques are able to produce dramatic savings in network bandwidth usage in a peer-to-peer virtual environment. In one test, this AOIM produced a 92% drop in network traffic, with a simultaneous 500% increase in world population.http://archive.org/details/dynamicscalablen109451616US Navy (USN) autho

Rough-terrain mobile robot planning and control with application to planetary exploration

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (leaves 119-130).Future planetary exploration missions will require mobile robots to perform difficult tasks in highly challenging terrain, with limited human supervision. Current motion planning and control algorithms are not well suited to rough-terrain mobility, since they generally do not consider the physical characteristics of the rover and its environment. Failure to understand these characteristics could lead to rover entrapment and mission failure. In this thesis, methods are presented for improved rough-terrain mobile robot mobility, which exploit fundamental physical models of the rover and terrain. Wheel-terrain interaction has been shown to be critical to rough terrain mobility. A wheel-terrain interaction model is presented, and a method for on-line estimation of important model parameters is proposed. The local terrain profile also strongly influences robot mobility. A method for on-line estimation of wheel-terrain contact angles is presented. Simulation and experimental results show that wheel-terrain model parameters and contact angles can be estimated on-line with good accuracy. Two rough-terrain planning algorithms are introduced. First, a motion planning algorithm is presented that is computationally efficient and considers uncertainty in rover sensing and localization. Next, an algorithm for geometrically reconfiguring the rover kinematic structure to optimize tipover stability margin is presented. Both methods utilize models developed earlier in the thesis.(cont.) Simulation and experimental results on the Jet Propulsion Laboratory Sample Return Rover show that the algorithms allow highly stable, semi-autonomous mobility in rough terrain. Finally, a rough-terrain control algorithm is presented that exploits the actuator redundancy found in multi-wheeled mobile robots to improve ground traction and reduce power consumption. The algorithm uses models developed earlier in the thesis. Simulation and experimental results show that the algorithm leads to improved wheel thrust and thus increased mobility in rough terrain.by Karl David Iagnemma.Ph.D

Performance Optimization Strategies for Transactional Memory Applications

This thesis presents tools for Transactional Memory (TM) applications that cover multiple TM systems (Software, Hardware, and hybrid TM) and use information of all different layers of the TM software stack. Therefore, this thesis addresses a number of challenges to extract static information, information about the run time behavior, and expert-level knowledge to develop these new methods and strategies for the optimization of TM applications

Modelling parallel and distributed virtual reality systems for performance analysis and comparison

Most Virtual Reality systems employ some form of parallel processing, making use of multiple processors which are often distributed over large areas geographically, and which communicate via various forms of message passing. The approaches to parallel decomposition differ for each system, as do the performance implications of each approach. Previous comparisons have only identified and categorized the different approaches. None have examined the performance issues involved in the different parallel decompositions. Performance measurement for a Virtual Reality system differs from that of other parallel systems in that some measure of the delays involved with the interaction of the separate components is required, in addition to the measure of the throughput of the system. Existing performance analysis approaches are typically not well suited to providing both these measures. This thesis describes the development of a performance analysis technique that is able to provide measures of both interaction latency and cycle time for a model of a Virtual Reality system. This technique allows performance measures to be generated as symbolic expressions describing the relationships between the delays in the model. It automatically generates constraint regions, specifying the values of the system parameters for which performance characteristics change. The performance analysis technique shows strong agreement with values measured from implementation of three common decomposition strategies on two message passing architectures. The technique is successfully applied to a range of parallel decomposition strategies found in Parallel and Distributed Virtual Reality systems. For each system, the primary decomposition techniques are isolated and analysed to determine their performance characteristics. This analysis allows a comparison of the various decomposition techniques, and in many cases reveals trends in their behaviour that would have gone unnoticed with alternative analysis techniques. The work described in this thesis supports the Performance Analysis and Comparison of Parallel and Distributed Virtual Reality systems. In addition it acts as a reference, describing the performance characteristics of decomposition strategies used in Virtual Reality systems