Learnable Cross-Correlation based Filter-and-Sum Networks for Multi-channel Speech Separation

Multichannel source separation plays an important role in audio and speech signal processing. With recent advancements in deep neural networks (DNN), numerous DNN-based beamforming algorithms have been developed. To leverage spatial information, a time domain filter-and-sum network (FaSNet) was introduced, and the transform average concatenate (TAC) technique was subsequently adopted to further enhance separation performance. FaSNet captures spatial information by assessing cosine similarity between different channels; but this approach may have limited spatial resolution and could exhibit bias in noisy, reverberant environments, thereby potentially compromising performance. Motivated by the efficacy of the generalized cross-correlation (GCC) method in achieving reliable source localization in adverse environments, this paper introduces a learnable cross-correlation (LCC) module for FaSNet and FaSNet-TAC. By offering improved flexibility and robustness across diverse environments, LCC enhances source separation performance, which is validated by several simulations.