Visualization in Human-Centered Virtual Factories

In a manufacturing system (MS), a wide range of human activities are applied in production processes. The human factor plays a core role and should be incorporated into the design, planning and decision making processes. In this work we describe different definitions, developments and existing concepts of a Virtual Factory (VF) and discuss VFs from the human oriented point of view. Furthermore, we analyze the potential need and use of visualization methods in VF study and propose a human-centered VF concept. Following this concept we introduce an example implementation and describe how our model facilitates the decision making and design process in MS. In addition, we show an example of a noise analysis of working environment, which is based on our virtual factory model

Audio-visual Virtual Reality System for Room Acoustics

We present an audio-visual Virtual Reality display system for simulated sound fields. In addition to the room acoustic simulation by means of phonon tracing and finite element method this system includes the stereoscopic visualization of simulation results using a 3D back projection system as well as auralization by use of a professional sound equipment. For auralization purposes we develop a sound field synthesis approach for accurate control of the loudspeaker system

On the Computation of Integral Curves in Adaptive Mesh Refinement Vector Fields

Integral curves, such as streamlines, streaklines, pathlines, and timelines, are an essential tool in the analysis of vector field structures, offering straightforward and intuitive interpretation of visualization results. While such curves have a long-standing tradition in vector field visualization, their application to Adaptive Mesh Refinement (AMR) simulation results poses unique problems. AMR is a highly effective discretization method for a variety of physical simulation problems and has recently been applied to the study of vector fields in flow and magnetohydrodynamic applications. The cell-centered nature of AMR data and discontinuities in the vector field representation arising from AMR level boundaries complicate the application of numerical integration methods to compute integral curves. In this paper, we propose a novel approach to alleviate these problems and show its application to streamline visualization in an AMR model of the magnetic field of the solar system as well as to a simulation of two incompressible viscous vortex rings merging

On the Computation of Integral Curves in Adaptive Mesh Refinement Vector Fields

Integral curves, such as streamlines, streaklines, pathlines, and timelines, are an essential tool in the analysis of vector field structures, offering straightforward and intuitive interpretation of visualization results. While such curves have a long-standing tradition in vector field visualization, their application to Adaptive Mesh Refinement (AMR) simulation results poses unique problems. AMR is a highly effective discretization method for a variety of physical simulation problems and has recently been applied to the study of vector fields in flow and magnetohydrodynamic applications. The cell-centered nature of AMR data and discontinuities in the vector field representation arising from AMR level boundaries complicate the application of numerical integration methods to compute integral curves. In this paper, we propose a novel approach to alleviate these problems and show its application to streamline visualization in an AMR model of the magnetic field of the solar system as well as to a simulation of two incompressible viscous vortex rings merging

Acoustic Simulation and Visualization Algorithms

Computer-based simulation and visualization of acoustics of a virtual scene can aid during the design process of concert halls, lecture rooms, theaters, or living rooms. Because, not only the visual aspect of the room is important, but also its acoustics. In factory floors noise reduction is important since noise is hazardous to health. Despite the obvious dissimilarity between our aural and visual senses, many techniques required for the visualization of photo-realistic images and for the auralization of acoustic environments are quite similar. Both applications can be served by geometric methods such as particle- and ray tracing if we neglect a number of less important effects. By means of the simulation of room acoustics we want to predict the acoustic properties of a virtual model. For auralization, a pulse response filter needs to be assembled for each pair of source and listener positions. The convolution of this filter with an anechoic source signal provides the signal received at the listener position. Hence, the pulse response filter must contain all reverberations (echos) of a unit pulse, including their frequency decompositions due to absorption at different surface materials. For the room acoustic simulation a method named phonon tracing, since it is based on particles, is developed. The approach computes the energy or pressure decomposition for each particle (phonon) sent out from a sound source and uses this in a second pass (phonon collection) to construct the response filters for different listeners. This step can be performed in different precision levels. During the tracing step particle paths and additional information are stored in a so called phonon map. Using this map several sound visualization approaches were developed. From the visualization, the effect of different materials on the spectral energy / pressure distribution can be observed. The first few reflections already show whether certain frequency bands are rapidly absorbed. The absorbing materials can be identified and replaced in the virtual model, improving the overall acoustic quality of the simulated room. Furthermore an insight into the pressure / energy received at the listener position is possible. The phonon tracing algorithm as well as several sound visualization approaches are integrated into a common system utilizing Virtual Reality technologies in order to facilitate the immersion into the virtual scene. The system is a prototype developed within a project at the University of Kaiserslautern and is still a subject of further improvements. It consists of a stereoscopic back-projection system for visual rendering as well as professional audio equipment for auralization purposes.Computergestützte Simulation und Visualisierung der akustischen Verhältnisse eines geschlossenen Raumes kann beim Design von Konzertsälen, Vorlesungsräumen, Theratern oder aber auch Wohnzimmern helfen. Denn nicht nur die visuelle Erscheinung eines Raumes sondern auch seine Akustik ist für eine angenehme Atmosphäre im Raum entscheidend. In Fabrikhallen ist die Lärmbekämpfung eine wichtige Aufgabe, denn Lärm ist gesundheitsschädigend. Abgesehen von den offensichtlichen Unterschieden zwischen dem Seh- und dem Hörsinn eines Menschen, sind viele Techniken, die bei der fotorealistischen Darstellung von Bildern und Auralisation akustischer Umgebungen eingesetzt werden, einander sehr ähnlich. Beide Probleme können mit Hilfe von geometrischen Ansätzen wie Ray-tracing oder Particle-tracing gelöst werden wenn einige, weniger wichtige Effekte, vernachlässigt werden. Mit Hilfe der Simulation wollen wir die akustischen Eigenschaften eines virtuellen Modells vorhersagen. Für die Auralisation muss eine Impulsantwort für jede Konstellation von Schallquelle und Zuhörer bestimmt werden. Die Faltung der Impulsantwort mit einem echolosen Signal ergibt das an der Zuhörerposition empfangene Schallereignis. Die Impulsantwort enthält alle reflektierten Anteile des Schalls, die durch die unterschiedlichen Materialien des Raumes beeinflusst werden. Betreffend der Raumakustiksimulation wurde im Rahmen dieser Dissertation ein Simulationsalgorithmus, namens Phonon Tracing, entwickelt, welcher auf Schallteilchenverfolgung basiert. Das Verfahren berechnet die Energie bzw. den Druck eines Schallteilchens, das von der Schallquelle ausgesandt wird, und verwendet diese Information zur Konstruktion der Antwort auf ein Schallereignis an einer vorgegebenen Hörposition im Raum. Während des Verfolgens der Schallteilchen, werden deren Pfade, sowie weitere Informationen in der sogenannten Phonon Map gespeichert. Unter Verwendung dieser Informationen wurden verschiedene Visualisierungsansätze für die Schallausbreitung von der Schallquelle, sowie des beim Zuhörer ankommenden Schallanteils entwickelt. Diese erlauben eine Analyse der akustischen Verhältnisse in dem zu untersuchenden Raum. Der Simulationsalgorithmus und die Visualisierungsmethoden wurden in ein gemeinsames System integriert, welches Virtual Reality Technologien anwendet um eine bessere Immersion in die virtuelle Welt zu gewährleisten. Das System wurde als Prototyp im Rahmen eines Projektes an der TU Kaiserslautern entwickelt und befindet sich zur Zeit in Weiterentwicklung. Es beinhaltet ein stereoskopisches Rückprojektionssystem für das visuelle Rendering und eine professionelle Audioanlage zur akustischen Ausgabe im Ziele der Auralisation

Acoustic Simulation and Visualization Algorithms

Computer-based simulation and visualization of acoustics of a virtual scene can aid during the design process of concert halls, lecture rooms, theaters, or living rooms. Because, not only the visual aspect of the room is important, but also its acoustics. In factory floors noise reduction is important since noise is hazardous to health. Despite the obvious dissimilarity between our aural and visual senses, many techniques required for the visualization of photo-realistic images and for the auralization of acoustic environments are quite similar. Both applications can be served by geometric methods such as particle- and ray tracing if we neglect a number of less important effects. By means of the simulation of room acoustics we want to predict the acoustic properties of a virtual model. For auralization, a pulse response filter needs to be assembled for each pair of source and listener positions. The convolution of this filter with an anechoic source signal provides the signal received at the listener position. Hence, the pulse response filter must contain all reverberations (echos) of a unit pulse, including their frequency decompositions due to absorption at different surface materials. For the room acoustic simulation a method named phonon tracing, since it is based on particles, is developed. The approach computes the energy or pressure decomposition for each particle (phonon) sent out from a sound source and uses this in a second pass (phonon collection) to construct the response filters for different listeners. This step can be performed in different precision levels. During the tracing step particle paths and additional information are stored in a so called phonon map. Using this map several sound visualization approaches were developed. From the visualization, the effect of different materials on the spectral energy / pressure distribution can be observed. The first few reflections already show whether certain frequency bands are rapidly absorbed. The absorbing materials can be identified and replaced in the virtual model, improving the overall acoustic quality of the simulated room. Furthermore an insight into the pressure / energy received at the listener position is possible. The phonon tracing algorithm as well as several sound visualization approaches are integrated into a common system utilizing Virtual Reality technologies in order to facilitate the immersion into the virtual scene. The system is a prototype developed within a project at the University of Kaiserslautern and is still a subject of further improvements. It consists of a stereoscopic back-projection system for visual rendering as well as professional audio equipment for auralization purposes.Computergestützte Simulation und Visualisierung der akustischen Verhältnisse eines geschlossenen Raumes kann beim Design von Konzertsälen, Vorlesungsräumen, Theratern oder aber auch Wohnzimmern helfen. Denn nicht nur die visuelle Erscheinung eines Raumes sondern auch seine Akustik ist für eine angenehme Atmosphäre im Raum entscheidend. In Fabrikhallen ist die Lärmbekämpfung eine wichtige Aufgabe, denn Lärm ist gesundheitsschädigend. Abgesehen von den offensichtlichen Unterschieden zwischen dem Seh- und dem Hörsinn eines Menschen, sind viele Techniken, die bei der fotorealistischen Darstellung von Bildern und Auralisation akustischer Umgebungen eingesetzt werden, einander sehr ähnlich. Beide Probleme können mit Hilfe von geometrischen Ansätzen wie Ray-tracing oder Particle-tracing gelöst werden wenn einige, weniger wichtige Effekte, vernachlässigt werden. Mit Hilfe der Simulation wollen wir die akustischen Eigenschaften eines virtuellen Modells vorhersagen. Für die Auralisation muss eine Impulsantwort für jede Konstellation von Schallquelle und Zuhörer bestimmt werden. Die Faltung der Impulsantwort mit einem echolosen Signal ergibt das an der Zuhörerposition empfangene Schallereignis. Die Impulsantwort enthält alle reflektierten Anteile des Schalls, die durch die unterschiedlichen Materialien des Raumes beeinflusst werden. Betreffend der Raumakustiksimulation wurde im Rahmen dieser Dissertation ein Simulationsalgorithmus, namens Phonon Tracing, entwickelt, welcher auf Schallteilchenverfolgung basiert. Das Verfahren berechnet die Energie bzw. den Druck eines Schallteilchens, das von der Schallquelle ausgesandt wird, und verwendet diese Information zur Konstruktion der Antwort auf ein Schallereignis an einer vorgegebenen Hörposition im Raum. Während des Verfolgens der Schallteilchen, werden deren Pfade, sowie weitere Informationen in der sogenannten Phonon Map gespeichert. Unter Verwendung dieser Informationen wurden verschiedene Visualisierungsansätze für die Schallausbreitung von der Schallquelle, sowie des beim Zuhörer ankommenden Schallanteils entwickelt. Diese erlauben eine Analyse der akustischen Verhältnisse in dem zu untersuchenden Raum. Der Simulationsalgorithmus und die Visualisierungsmethoden wurden in ein gemeinsames System integriert, welches Virtual Reality Technologien anwendet um eine bessere Immersion in die virtuelle Welt zu gewährleisten. Das System wurde als Prototyp im Rahmen eines Projektes an der TU Kaiserslautern entwickelt und befindet sich zur Zeit in Weiterentwicklung. Es beinhaltet ein stereoskopisches Rückprojektionssystem für das visuelle Rendering und eine professionelle Audioanlage zur akustischen Ausgabe im Ziele der Auralisation

Phonon Tracing for Auralization and Visualization of Sound

We present a new particle tracing approach for the simulation of mid- and high-frequency sound. Inspired by the photorealism obtained by methods like photon mapping, we develop a similar method for the physical simulation of sound within rooms. For given source and listener positions, our method computes a finite- response filter accounting for the different reflections at various surfaces with frequency-dependent absorption coefficients. Convoluting this filter with an anechoic input signal reproduces a realistic aural impression of the simulated room. We do not consider diffraction effects due to low frequencies, since these can be better computed by finite elements. Our method allows the visualization of a wavefront propagation using color-coded blobs traversing the paths of individual phonons

Listener-based Analysis of Surface Importance for Acoustic Metrics

Acoustic quality in room acoustics is measured by well defined quantities, like definition, which can be derived from simulated impulse response filters or measured values. These take into account the intensity and phase shift of multiple reflections due to a wave front emanating from a sound source. Definition (D50) and clarity (C50) for example correspond to the fraction of the energy received in total to the energy received in the first 50 ms at a certain listener position. Unfortunately, the impulse response measured at a single point does not provide any information about the direction of reflections, and about the reflection surfaces which contribute to this measure. For the visualization of room acoustics, however, this information is very useful since it allows to discover regions with high contribution and provides insight into the influence of all reflecting surfaces to the quality measure. We use the phonon tracing method to calculate the contribution of the reflection surfaces to the impulse response for different listener positions. This data is used to compute importance values for the geometry taking a certain acoustic metric into account. To get a visual insight into the directional aspect, we map the importance to the reflecting surfaces of the geometry. This visualization indicates which par ts of the surfaces need to be changed to enhance the chosen acoustic quality measure. We apply our method to the acoustic improvement of a lecture hall by means of enhancing the overall speech comprehensibility (clarity) and evaluate the results using glyphs to visualize the clarity (C50) values at listener positions throughout the room

Simulation, Visualization, and Virtual Reality based Modeling of Room Acoustics

We present an audio-visual Virtual Reality display system for simulated sound fields. This system combines the simulation of acoustics inside closed rooms, different approaches for visualizing the sound propagation as well as the auralization of the resulting signals. The room acoustic simulation is performed by use of a particle tracing algorithm, the Phonon Tracing, applied at middle and high frequency range, combined with a wave-based approach (FEM solver) utilized for low frequencies. For a realistic representation of the simulation results we use a stereoscopic back projection system for rendering as well as a professional sound system for audio reproduction. For auralization purposes we developed a soundfield synthesis approach for accurate control of the loudspeaker system

Visualizing the Phonon Map

In this work we present several visualization approaches for analyzing acoustic behavior inside a room. Our methods are based on the results of the phonon tracing algorithm. For a simulated phonon map we examine the influence of the room surfaces on the wave fronts during their propagation from the sound source. Our visualization is based on individual phonon and surface representations as well as scattered data interpolation. Additionally, an observation of acoustic behavior at different positions inside the room using colored and deformed spheres is possible