Reconstruction of a recorded sound field

摘要

Equipment (10) for reconstructing a recorded sound field includes a sensing arrangement (12) for measuring the sound field to obtain recorded data. A signal processing module (14) is in communication with the sensing arrangement (12) and processes the recorded data for the purposes of at least one of (a) estimating the sparsity of the recorded sound field and (b) obtaining plane-wave signals to enable the recorded sound field to be reconstructed.

主权项

1. A method of reconstructing a recorded sound field, the method including
analysing recorded data in a sparse domain using one of a time domain technique and a frequency domain technique and, when using a frequency domain technique transforming the set of signals, smic(t), to the frequency domain using an FFT to obtain smic; conducting a plane-wave analysis of the recorded sound field to produce a vector of frequency domain plane-wave amplitudes, gplw-cs by solving the following convex programming problem:minimise⁢⁢gplw⁢-⁢cs1subject⁢⁢to⁢⁢Tplw/mic⁢gplw⁢-⁢cs-smic2smic2≤ɛ1where:
Tplw/mic is a transfer matrix between plane-waves and the microphones, smic is the set of signals recorded by the microphone array, and ε1 is a non-negative real number; and, when using a time domain technique, analysing the recorded sound field by convolving smic(t) with a matrix of filters to obtain a vector of HOA-domain time signals, bHOA(t), and sampling the vector of HOA-domain time signals over a given time frame, L, to obtain a collection of time samples at time instances t1 to tN to obtain a set of HOA-domain vectors at each time instant: bHOA(t1), bHOA(t2), . . . , bHOA(tN) expressed as a matrix, BHOA by:
BHOA=[bHOA(t1)bHOA(t2) . . . bHOA(tN)]; and conducting plane-wave analysis of the recorded sound field according to a set of basis Mane-waves to produce a set of lane-wave signals gplw-cs(t), from Gplw which is obtained by solving the following convex programming problem:
minimize ∥Gplw∥L1-L2 subject to ∥YplwGplw−BHOA∥L2≦ε1,where
Yplw is a matrix (truncated to a high spherical harmonic order) whose columns are the values of the spherical harmonic functions for the set of directions corresponding to some set of analysis plane waves, and ε1 is a non-negative real number; obtaining plane-wave signals and their associated source directions generated from the selected technique to enable the recorded sound field to be reconstructed; and playing back the reconstructed, recorded sound field over one of loudspeakers and headphones.