Inverse harmonic clustering for multi-pitch estimation: an optimal transport approach

Fuente: arXiv
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Main Authors: Björkman, Anton, Elvander, Filip
Format: Preprint
Published: 2025
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author Björkman, Anton
Elvander, Filip
author_facet Björkman, Anton
Elvander, Filip
contents In this work, we consider the problem of multi-pitch estimation, i.e., identifying super-imposed truncated harmonic series from noisy measurements. We phrase this as recovering a harmonically-structured measure on the unit circle, where the structure is enforced using regularizers based on optimal transport theory. In the resulting framework, a signal's spectral content is simultaneously inferred and assigned, or transported, to a small set of harmonic series defined by their corresponding fundamental frequencies. In contrast to existing methods from the compressed sensing paradigm, the proposed framework decouples regularization and dictionary design and mitigates coherency problems. As a direct consequence, this also introduces robustness to the phenomenon of inharmonicity. From this framework, we derive two estimation methods, one for stochastic and one for deterministic signals, and propose efficient numerical algorithms implementing them. In numerical studies on both synthetic and real data, the proposed methods are shown to achieve better estimation performance as compared to other methods from statistical signal processing literature. Furthermore, they perform comparably or better than network-based methods, except when the latter are specially trained on the data-type considered and are given access to considerably more data during inference.
format Preprint
id arxiv_https___arxiv_org_abs_2508_02471
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Inverse harmonic clustering for multi-pitch estimation: an optimal transport approach
Björkman, Anton
Elvander, Filip
Signal Processing
In this work, we consider the problem of multi-pitch estimation, i.e., identifying super-imposed truncated harmonic series from noisy measurements. We phrase this as recovering a harmonically-structured measure on the unit circle, where the structure is enforced using regularizers based on optimal transport theory. In the resulting framework, a signal's spectral content is simultaneously inferred and assigned, or transported, to a small set of harmonic series defined by their corresponding fundamental frequencies. In contrast to existing methods from the compressed sensing paradigm, the proposed framework decouples regularization and dictionary design and mitigates coherency problems. As a direct consequence, this also introduces robustness to the phenomenon of inharmonicity. From this framework, we derive two estimation methods, one for stochastic and one for deterministic signals, and propose efficient numerical algorithms implementing them. In numerical studies on both synthetic and real data, the proposed methods are shown to achieve better estimation performance as compared to other methods from statistical signal processing literature. Furthermore, they perform comparably or better than network-based methods, except when the latter are specially trained on the data-type considered and are given access to considerably more data during inference.
title Inverse harmonic clustering for multi-pitch estimation: an optimal transport approach
topic Signal Processing
url https://arxiv.org/abs/2508.02471