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Title: Acoustic reflector localisation for blind source separation and spatial audio
Author: Remaggi, Luca
ISNI:       0000 0004 6422 8813
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 2017
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From a physical point of view, sound is classically defined by wave functions. Like every other physical model based on waves, during its propagation, it interacts with the obstacles it encounters. These interactions result in reflections of the main signal that can be defined as either being supportive or interfering. In the signal processing research field, it is, therefore, important to identify these reflections, in order to either exploit or avoid them, respectively. The main contribution of this thesis focuses on the acoustic reflector localisation. Four novel methods are proposed: a method localising the image source before finding the reflector position; two variants of this method, which utilise information from multiple loudspeakers; a method directly localising the reflector without any pre-processing. Finally, utilising both simulated and measured data, a comparative evaluation is conducted among different acoustic reflector localisation methods. The results show the last proposed method outperforming the state-of-the-art. The second contribution of this thesis is given by applying the acoustic reflector localisation solution into spatial audio, with the main objective of enabling the listeners with the sensation of being in the recorded environment. A novel way of encoding and decoding the room acoustic information is proposed, by parametrising sounds, and defining them as reverberant spatial audio objects (RSAOs). A set of subjective assessments are performed. The results prove both the high quality of the sound produced by the proposed parametrisation, and the reliability on manually modifying the acoustic of recorded environments. The third contribution is proposed in the field of speech source separation. A modified version of a state-of-the-art method is presented, where the direct sound and first reflection information is utilised to model binaural cues. Experiments were performed to separate speech sources in different environments. The results show the new method to outperform the state-of-the-art, where one interferer is present in the recordings. The simulation and experimental results presented in this thesis represent a significant addition to the literature and will influence the future choices of acoustic reflector localisation systems, 3D rendering, and source separation techniques. Future work may focus on the fusion of acoustic and visual cues to enhance the acoustic scene analysis.
Supervisor: Jackson, Philip Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available