Kontextabhängige Parameter bei der Qualitätsbeurteilung binauraler Kopfhörersysteme. - In: Fortschritte der Akustik, (2015), S. 1599-1601
Distribution of quadrant errors in auditory localization using a binaural headphone system. - In: Fortschritte der Akustik, (2015), S. 1094-1096
The auditory system of humans enables the perception of spatial audio in real and virtual acoustics using monaural and binaural cues. The perception of direction and distance are two prominent quality features to evaluate the quality of experience of spatial audio systems. Inaccuracies in perception can occur if physical quality elements of the synthesis system are not adequate. In this study a binaural synthesis via headphones is used to re-synthesize single sound sources on several discrete positions on a full circle around the listener. An artificial head (KEMAR) and a two channel spherical microphone setup are used to measure binaural room impulse responses in a real environment. A listening test is performed to measure the number of quadrant errors and perceived externalization of the auditory events in a localization task. The distributions of its frequencies depending on the direction of the re-synthesized sound source are investigated. The results show a continuous relationship between the investigated quality features and the direction of the sound source. Furthermore, an analysis of the relationship between quadrant errors and externalization depending on direction and used binaural room impulse responses are presented.
Influence of context dependent quality parameters on the perception of externalization and direction of an auditory event. - In: Spatial audio, ISBN 978-1-63439-759-9, (2015), S. 305-312
Next to an adequate technical realization of an audio reproduction system, the context of usage plays a major role if a perfect auditory illusion with immersion and plausibility is aspired. This contribution presents results from perceptual experiments on context dependent quality parameters. A binaural synthesis of an acoustic scene via a personalized headphone system is used. The investigated quality parameters are influenced by divergence between synthesized scene and listening room, visibility of the scene, and personalization of the system. The plausibility of the perceived auditory scene is described by the test persons with the help of the quality features perceived externalization and direction of the auditory event. The analysis shows that there are significant differences in perceived externalization depending on the occurrence of localization errors but also on divergence or congruence between the listening and synthesized room.
Verbesserung der Dateiverarbeitungskette in Betriebssystemen durch Nutzung der Skalierbarkeit moderner Kompressionsverfahren, 2015. - Online-Ressource (PDF-Datei: VI, 158 Bl., 12,87 KB) Ilmenau : Techn. Univ., Diss., 2015
Motiviert durch die aktuellen Herausforderungen im Bereich der computergestützten Bearbeitung vom Multimediadaten, leistet die vorliegende Arbeit einen Beitrag zum Forschungsgebiet der Datenverarbeitung und Dateiverwaltung innerhalb von Computersystemen durch neuartige Verfahren zur Nutzung skalierbarer Medien unter Verwendung vorhandener Datei- und Betriebssysteme. Hierzu werden die Kompressionsformate JPEG 2000 und H.264 SVC vorgestellt und gezeigt, wie die Eigenschaft der Skalierbarkeit innerhalb der verschiedenen Verfahren erreicht wird. Es folgt eine Analyse der limitierenden Hard- und Softwarekomponenten in einem Computersystem für das o.g. Einsatzgebiet. Ausgehend vom hohen Aufwand zur Kompensation der Leistungsengpässe werden anschließend neue Lösungsansätze unter Nutzung skalierbarer Medienformate abgeleitet, die nachfolgend untersucht werden. Die vorliegende Arbeit zeigt hierzu neue Konzepte zur Verwaltung skalierbarer Mediendaten, die durch ein neues Rechtemanagement sowie durch eine speicheradaptive Ablagestrategie abgedeckt werden. Das Rechtemanagement erlaubt die Vergabe von Zugriffsrechten auf verschiedene Abschnitte einer Datei, wodurch die Skalierbarkeit der Medien derart abgebildet werden kann, dass verschiedene Benutzer unterschiedliche Varianten einer Datei angezeigt bekommen. Die speicheradaptive Ablagestrategie erreicht Durchsatzsteigerungen der verwendeten Datenträger, wenn das spätere Zugriffsverhalten auf die gespeicherten Medien vorab bekannt ist. Weiter werden Verbesserungen der Verarbeitungsabläufe unter Ausnutzung skalierbarer Medien gezeigt. Auf Basis der entwickelten Substitutionsmethode zur Kompensation fehlender Daten einer skalierbaren Datei wird eine echtzeitfähige Einlesestrategie vorgestellt, die unzureichende Durchsatzraten von Speichermedien bzw. langsamen Schnittstellen derart kompensieren kann, dass eine unterbrechungsfreie Ausspielung von Bildsequenzen bei einer vorgegebenen Bildwiederholrate gewährleistet werden kann. Angepasste Cache-Strategien ermöglichen eine Steigerung der im Cache vorhaltbaren Einzelbilder im Vergleich zu nicht skalierbaren Varianten. Darüber hinaus wird das Konzept eines parametrisierbaren Dateiaufrufes eingeführt, wodurch mittels Zusatzinformationen im virtuellen Dateinamen eine gewünschte Variante einer skalierbaren Datei vom Datenspeicher angefragt werden kann.
http://www.db-thueringen.de/servlets/DocumentServlet?id=26056
Context and plausibility in binaural synthesis. - In: Proceedings of the International Conference on Spatial Audio, ICSA 2014 in Erlangen, Germany, ISBN 978-3-9812830-4-4, (2014), S. 189-192
The development of recording and playback systems is motivated by the goal to create a perfect auditory illusion. In the last decades audio systems like ambisonics, wave field synthesis and binaural headphone reproduction gained in importance. Efforts are made to increase the quality of such systems. Despite the years of research and development, there are still many perceptual effects and psychoacoustical factors which are still unknown or not fully understood. This contribution presents a research project which deals with the systematically analysis of perceptual effects regarding to binaural playback. Based on the results of listening tests a measurement model on the perception of binaural synthesized scenes is developed. For this, a set of quality features needs to be determined and evaluated. These quality features and their weightings can be summarized as plausibility of perception. The plausibility of a binaural auralization does not only depend on physical quality elements of the synthesis system, but also depends significantly on contextual factors. During the project several different auditive scenes are created for evaluation. The contextual factors which influence the quality features are varied. Different rooms for playback and recording are considered as well as variations of the complexity of the acoustical scene, the degree of personalization and the type of visual presentation. Dependencies between these factors are expected and are going to be evaluated. This contribution presents first results of contextual factors influencing quality features.
Multidimensionality and context dependencies in quality evaluation of spatial audio signals. - In: Proceedings of the International Conference on Spatial Audio, ICSA 2014 in Erlangen, Germany, ISBN 978-3-9812830-4-4, (2014), S. 154-158
To authentically reproduce spatial audio signals it is important to know how these signals are perceived and evaluated by the subjects. The quality of the spatial audio signal can be described in overall quality, called the basic audio quality, or can be stripped down into several quality features. In the literature numerous experiments are conducted in which the multi-dimensionality of spatial audio signals is investigated. Results of these experiments are only reliable for the room in which they were performed. In this project the room is assumed as the contextual factor. The perception of the spatial audio signal is context dependent, this is especially important for loudspeaker reproduction. Goal of the research topic is to find consistent quality features and to assign them either to the technical signal or to the context. The second step is to define a standardised method to evaluate the quality features in different contexts and achieve reproducible and reliable results. A first approach is to evaluate quality features known from previous studies and to explore their correlation with the basic audio quality. This will be done in different reproduction rooms with different room characteristics with the use of a 5.0 loudspeaker setup. The project and the structure of the first listening test is described in this contribution.
Adjustment of direct-to-reverberant-energy-ratio and the just-noticable-difference. - In: Sixth International Workshop on Quality of Multimedia Experience (QoMEX), 2014, ISBN 978-1-4799-6536-6, (2014), insges. 3 S.
The adjustment of the direct-to-reverberant-energy-ratio (DRR) within a binaural synthesis system is assessed in a listening test. The DRR is changed until the assessors perceive congruence between the synthesized and listening room. The results of the experiment are relevant to apply adaption methods on binaural synthesis to increase plausibility involving context dependent quality parameters like room divergences between the synthesized auditory scene and the listening environment. Furthermore, a discussion is aspired about the relationship between justnoticeable- difference in DRR perception and inter-quartiledistances of the adjusted DRRs.
http://dx.doi.org/10.1109/QoMEX.2014.7138310
Perspektiven zur Anwendung der Binauralsynthese in der Medienproduktion. - In: Medienproduktion, ISSN 2193-7699, No. V (2014), Seite 12-14
http://zs.thulb.uni-jena.de/receive/jportal_jpvolume_00202970
Model-based prediction towards the limitations of binocular gaze tracking for 3DTV-Applications. - In: IEEE Fourth International Conference on Consumer Electronics - Berlin (ICCE-Berlin), 2014, ISBN 978-1-4799-6166-5, (2014), S. 142-143
This paper presents work towards the development of an accurate binocular eye tracking system. For that to happen, virtual eye tracking data is prepared. This is based on defined suitable parameters considering complex influencing factors from the distinctive use case. This work in progress presentation is concluded by results of an initial study with a prototypical eye tracking system. Here, the prepared virtual eye tracking data is processed instead of real camera recordings. The results show that based on pre-defined parameters the virtual eye tracking data is useful to support the development process towards more precise and accurate binocular eye tracking systems.
http://dx.doi.org/10.1109/ICCE-Berlin.2014.7034241
Linking quality features and quality elements by defining an extended 3DVO quality taxonomy model. - In: Sixth International Workshop on Quality of Multimedia Experience (QoMEX), 2014, ISBN 978-1-4799-6536-6, (2014), S. 41-46
This work presents a proposal for a quality measure that focuses on the user's subjective quality of experience. The challenges are to define factors that influence quality and to link up the quality of experience with the technical realization process. The advantages of interlinking the quality of experience with the quality of service are to profit the technical realization process in order to allow adaptability (e.g., based on used systems at the end users side) as well as scalability (e.g., based on a cost or resources limitation) in a user centered way. The current work outlines a suggestion for user centered quality taxonomy as an interlinking model. The outlined results consist of a systematic definition of quality features defined by the method Open Profiling of Quality. Based on this, a taxonomy model is presented that links up these results with the technical creation processes including a formalized quality measure.
http://dx.doi.org/10.1109/QoMEX.2014.6982285