| Feature | Description |
|---|---|
| Zero-crossing Rate | Measures the number of times a signal changes its sign from positive to negative or vice versa, divided by the length of the frame. In other words, it represents the frequency with which the signal crosses the zero axis. |
| Mean-crossing Rate | Calculates the number of times the signal crosses the mean value within the window. |
| Threshold-crossing Rate | Measures the frequency at which a signal crosses a predefined threshold value within a given time window. |
| Positive Sigma Crossing Rate | Measures how frequently a signal exceeds a threshold defined as a multiple of the standard deviation (σ) above the mean. This feature helps identify significant deviations in signal amplitude and is particularly useful for detecting repetitive patterns or anomalies in time-series data. |
| Negative Sigma Crossing Rate | Measures how frequently a signal falls below a threshold defined as a multiple of the standard deviation (σ) below the mean. This feature helps identify significant downward deviations in signal amplitude and is particularly useful for detecting repetitive patterns or anomalies in time-series data. |