Series Centroid
centroid
Computes the centroid along the time axis.
Low value: Means the primary/patterns fluctuations of the series occur slowly.
High value: Means the primary patterns/fluctuations of the series occur rapidly, with fast and short-term changes.
| Parameter | Type | Default | Description |
|---|---|---|---|
| fs | int | Mandatory | Sampling frequency |
Calculation
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Power Spectral Density (PSD): The PSD of the time series is computed, which shows the power of the signal at each frequency f.
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Centroid Calculation: The spectral centroid C, which is returned, is computed as the power-weighted average of the frequencies. The sum is over all frequency bins k.
Practical Usefulness Examples
Audio Analysis: In music information retrieval, the spectral centroid distinguishes between "bright" sounds (high centroid, like cymbals) and "dull" sounds (low centroid, like a bass drum), aiding in instrument recognition or genre classification.
Vibration Analysis: For machine diagnostics, a shift in the spectral centroid of vibration signals can indicate changes in operational speed or the emergence of specific fault frequencies (bearing defects often have characteristic high-frequency components, for example).