Sparsity Based Analysis of Sound Field Diffuseness in Rooms

A spatio-spectro-temporal (SST) sound field analysis approach based on a sparse plane-wave decomposition
of sound fields captured using a higher-order Ambisonics microphone is proposed. This approach analyzes the
progression of sound field diffuseness in both temporal and spatial dimensions. Derivative measures assess temporal,
spectro-temporal, and spatio-temporal characteristics of the diffuse field, including sparsity, diversity, and isotropy.
We define the room sparsity profile (RSP), room sparsity relief (RSR), and room sparsity profile diversity (RSPD)
as temporal, spectro-temporal, and spatio-temporal measures of diffuse fields, respectively. The relationship of
this approach to existing diffuseness measures is discussed and supported by experimental comparisons using
fourth-order acoustic impulse responses (AIRs), demonstrating the utility of the new derivative measures on
measurement position.