Diffuseness estimation via surface arrays for Directional Audio Coding

In Directional Audio Coding, a spatial audio technique for communications, the degree of diffuseness of the sound field represents an important parameter. Its estimation is traditionally carried out by means of an averaging in time domain, which inherently degrades the temporal resolution of the parameter. This is undesired since many relevant signal types, such as speech, are characterised by considerable temporal variability. This contribution proposes and investigates the use of spatial averaging by means of employing multiple sensors to improve the temporal resolution of the diffuseness parameter. The derivation of the spatial correlation function for ideal diffuse sound fields allows to design the sensor array optimally. Simulations and measurements confirm the theoretical results.