Spatial decomposition by spherical array processing

This chapter presents an overview of the conventional plane-wave decomposition (PWD) method for spherical microphone arrays, as well as some recent advances that aim to provide improved PWD estimations. It starts with the conventional PWD method and describes the sources of noise amplification and spatial aliasing errors. The PWD methods differ in their regularization functions, leading to a different tradeoff between the two conflicting features, spatial resolution and robustness to noise. The chapter presents several PWD methods that provide a compromise between loss of spatial resolution and sensitivity to measurement noise. Both low spatial resolution and measurement noise produce inaccuracies that can be considered as errors in the estimated plane-wave coefficients. An optimal compromise between the spatial distortion and noise errors can be obtained by finding a regularization matrix that minimizes the overall PWD error.