On the Estimation of Acoustic Reflection Coefficients from In-Situ Measurements using a Spherical Microphone Array
* Presenting author
The acoustic reflection coefficients of surfaces are important parameters for geometric modelling. Various methods have been proposed to estimate these from in-situ measurements using one or more sources and microphones distributed in the environment of interest. One particularly illustrative method is to investigate the spatio-temporal structure of the plane wave decomposition of the sound field within the room. Peaks in this representation can be assigned to mirror image sources. This contribution examines the application of a rigid spherical microphone array together with modal beamforming. We elaborate on algorithmic choices for the automatic localization of mirror image sources, as well as for the estimation of frequency-dependent reflection coefficients. The influence of practical limitations, like the number of microphones and their self-noise, is investigated. Both numerical simulations as well as practical measurements are considered.