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Title: In-system parametric calibration for two-microphone wave separation in acoustic waveguides
Author: De Sanctis, Giovanni
ISNI:       0000 0004 2741 8167
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2012
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The separation of waves in acoustic waveguides can be used to infer information from various acoustic systems. When applied to musical wind instruments, it allows novel techniques for in-depth investigation of the physics of the instrument, including the extraction of playing information in wind instruments, bore reconstruction and impedance measurement. Although a few approaches to this problem can be found in the literature, little attention has been given to the calibration of the system and above all to the assessment of its performance. The proposed methodology is based on a frequency-domain optimisation of a small set of parameters that best describe the system. The nonlinear optimisation problem that arises is formulated in order to exploit the considerable amount of a-priori knowledge given by the theory of propagation in ducts. The resulting cost surface is typically characterised by several local minima; however, the initial guess given by the nominal values for the parameters ensures the convergence to the desired solution. The main feature of the optimisation approach is that it can be applied in system and does not require any special calibration apparatus. As a consequence, it is also possible to track slow variations in the propagation due to changes in temperature and humidity of the medium during normal operation. A procedure for the assessment of a wave separation algorithm is also proposed; this shows that, under the same conditions, the optimisation approach improves the performance of the system. Finally, the proposed frequency-domain optimisation is also suitable for other applications such as in-air direction of arrival estimation. Preliminary results on these applications are also presented.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available