HBP: An Efficient Block Permutation Solver Using Hungarian Algorithm and Spectrogram Inpainting for Multichannel Audio Source Separation

This paper proposes a method called "Hungarian Block Permutation (HBP)" to solve the block permutation problem in frequency-domain multichannel audio source separation. Many methods for frequency-domain multichannel audio source separation are designed to simultaneously solve frequency-wise source separation and permutation alignment in determined cases. However, in practice, separation can fail due to permutation inconsistencies in different frequency blocks for various reasons, such as convergence to a locally optimal solution as a result of bad initialization. To correct permutation inconsistencies, the proposed HBP method first masks, for each separated signal, the frequency bands where the components from other sources are likely to be dominant, and then restores the components in those bands so that the restored spectrogram becomes closer to the original spectrogram of the corresponding source. The Hungarian algorithm is then used to perform permutation realignment in those bands in accordance with the restored spectrogram. The experimental results show that the proposed method can solve the permutation realignment and improve the separation performance even in the case of 18 speakers.