Mind the Gap: Detecting Cluster Exits for Robust Local Density-Based Score Normalization in Anomalous Sound Detection

Fuente: arXiv
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Main Authors: Wilkinghoff, Kevin, Wichern, Gordon, Roux, Jonathan Le, Tan, Zheng-Hua
Format: Preprint
Published: 2026
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_version_ 1866910029003620352
author Wilkinghoff, Kevin
Wichern, Gordon
Roux, Jonathan Le
Tan, Zheng-Hua
author_facet Wilkinghoff, Kevin
Wichern, Gordon
Roux, Jonathan Le
Tan, Zheng-Hua
contents Local density-based score normalization is an effective component of distance-based embedding methods for anomalous sound detection, particularly when data densities vary across conditions or domains. In practice, however, performance depends strongly on neighborhood size. Increasing it can degrade detection accuracy when neighborhood expansion crosses cluster boundaries, violating the locality assumption of local density estimation. This observation motivates adapting the neighborhood size based on locality preservation rather than fixing it in advance. We realize this by proposing cluster exit detection, a lightweight mechanism that identifies distance discontinuities and selects neighborhood sizes accordingly. Experiments across multiple embedding models and datasets show improved robustness to neighborhood-size selection and consistent performance gains.
format Preprint
id arxiv_https___arxiv_org_abs_2602_18777
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mind the Gap: Detecting Cluster Exits for Robust Local Density-Based Score Normalization in Anomalous Sound Detection
Wilkinghoff, Kevin
Wichern, Gordon
Roux, Jonathan Le
Tan, Zheng-Hua
Audio and Speech Processing
Sound
Local density-based score normalization is an effective component of distance-based embedding methods for anomalous sound detection, particularly when data densities vary across conditions or domains. In practice, however, performance depends strongly on neighborhood size. Increasing it can degrade detection accuracy when neighborhood expansion crosses cluster boundaries, violating the locality assumption of local density estimation. This observation motivates adapting the neighborhood size based on locality preservation rather than fixing it in advance. We realize this by proposing cluster exit detection, a lightweight mechanism that identifies distance discontinuities and selects neighborhood sizes accordingly. Experiments across multiple embedding models and datasets show improved robustness to neighborhood-size selection and consistent performance gains.
title Mind the Gap: Detecting Cluster Exits for Robust Local Density-Based Score Normalization in Anomalous Sound Detection
topic Audio and Speech Processing
Sound
url https://arxiv.org/abs/2602.18777