Pitch and Onset Time Estimation of Electric Bass by Non-negative Matrix Factorization Considering Orthogonality of Onset Time

Abstract

This paper proposes a new regularization term of non-negative matrix factorization (NMF) for estimating pitch and onset time of electric bass. Both of them are indispensable information for automatic music transcription. However, it is difficult to estimate them from the electric bass performance because of trade-off problem between time resolution and frequency resolution. Applying the NMF simply to the electric bass performance, the correct note and its semitone are sometimes detected simultaneously. The proposed regularization term avoiding such miss detection based on the performance characteristic of the electric bass, that is, two notes are not generally played simultaneously. We define the regularization term in order to keep orthogonality of the adjacent activation decomposed by the NMF. As a result of the experiments using MIDI synthesizer-generated sound of electric bass and real played electric bass sound, it is confirmed that the F-measure of the proposed method is higher than that of comparative method.