Sub-Band Spectral Matching with Localized Score Aggregation for Robust Anomalous Sound Detection

Fuente: arXiv
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Autores principales: Saengthong, Phurich, Shinozaki, Takahiro
Formato: Preprint
Publicado: 2026
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author Saengthong, Phurich
Shinozaki, Takahiro
author_facet Saengthong, Phurich
Shinozaki, Takahiro
contents Detecting subtle deviations in noisy acoustic environments is central to anomalous sound detection (ASD). A common training-free ASD pipeline temporally pools frame-level representations into a band-preserving feature vector and scores anomalies using a single nearest-neighbor match. However, this global matching can inflate normal-score variance through two effects. First, when normal sounds exhibit band-wise variability, a single global neighbor forces all bands to share the same reference, increasing band-level mismatch. Second, cosine-based matching is energy-coupled, allowing a few high-energy bands to dominate score computation under normal energy fluctuations and further increase variance. We propose BEAM, which stores temporally pooled sub-band vectors in a memory bank, retrieves neighbors per sub-band, and uniformly aggregates scores to reduce normal-score variability and improve discriminability. We further introduce a parameter-free adaptive fusion to better handle diverse temporal dynamics in sub-band responses. Experiments on multiple DCASE Task 2 benchmarks show strong performance without task-specific training, robustness to noise and domain shifts, and complementary gains when combined with encoder fine-tuning.
format Preprint
id arxiv_https___arxiv_org_abs_2603_13749
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Sub-Band Spectral Matching with Localized Score Aggregation for Robust Anomalous Sound Detection
Saengthong, Phurich
Shinozaki, Takahiro
Sound
Artificial Intelligence
Detecting subtle deviations in noisy acoustic environments is central to anomalous sound detection (ASD). A common training-free ASD pipeline temporally pools frame-level representations into a band-preserving feature vector and scores anomalies using a single nearest-neighbor match. However, this global matching can inflate normal-score variance through two effects. First, when normal sounds exhibit band-wise variability, a single global neighbor forces all bands to share the same reference, increasing band-level mismatch. Second, cosine-based matching is energy-coupled, allowing a few high-energy bands to dominate score computation under normal energy fluctuations and further increase variance. We propose BEAM, which stores temporally pooled sub-band vectors in a memory bank, retrieves neighbors per sub-band, and uniformly aggregates scores to reduce normal-score variability and improve discriminability. We further introduce a parameter-free adaptive fusion to better handle diverse temporal dynamics in sub-band responses. Experiments on multiple DCASE Task 2 benchmarks show strong performance without task-specific training, robustness to noise and domain shifts, and complementary gains when combined with encoder fine-tuning.
title Sub-Band Spectral Matching with Localized Score Aggregation for Robust Anomalous Sound Detection
topic Sound
Artificial Intelligence
url https://arxiv.org/abs/2603.13749