Polyhedral audio system based on at least second-order eigenbeams

摘要

A microphone array-based audio system that supports representations of auditory scenes using second-order (or higher) harmonic expansions based on the audio signals generated by the microphone array. In one embodiment, a plurality of audio sensors are mounted on the surface of an acoustically rigid polyhedron that approximates a sphere. The number and location of the audio sensors on the polyhedron are designed to enable the audio signals generated by those sensors to be decomposed into a set of eigenbeams having at least one eigenbeam of order two (or higher). Beamforming (e.g., steering, weighting, and summing) can then be applied to the resulting eigenbeam outputs to generate one or more channels of audio signals that can be utilized to accurately render an auditory scene.

主权项

1. A microphone array comprising:
an acoustically rigid polyhedron comprising a plurality of faces; and a plurality of microphones, wherein:
each microphone is implemented on a different face of the acoustically rigid polyhedron; andthe positions of the microphones in the microphone array satisfy an orthonormality property given as follows:∑s=0M-1⁢αn⁢⁢m⁢Ynm*⁡(ϑs,φs)⁢Yn′m′⁡(ϑs,φs)≈M4⁢π⁢δnn′⁢δm⁢⁢m′,wherein:
δnn′ equals 1 when n=n′, and 0 otherwise; δmm′ equals 1 when m=m′, and 0 otherwise; M is the number of microphones in the microphone array; (s, φs) are angular position coordinates of microphone s in the microphone array; Yn′m′(s, φs) is a spheroidal harmonic function of order n′ and degree m′ at position (s, φs); Ynm*(s, φs) is a complex conjugate of the spheroidal harmonic function of order n and degree m at position Ynm*(s, φs); and αnm is a correction factor.