DETECT SIGN CHANGES BASED SIGN CHANGE¶
Scans a time-series curve for sign-change events (positive-to-negative or negative-to-positive zero crossings) subject to configurable minimum/maximum duration windows, fluctuation tolerance, and amplitude thresholds. Use this worker to isolate sustained polarity-reversal events in signals such as force, velocity, or displacement histories.
When to use¶
Classification: process.
Tagged: curve, event_detection, sign_change, signal, time_series, transformations, zero_crossing.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Curve | curve | vector | — | Input time-series curve (X = time, Y = signal value) on which sign-change event detection is performed; accepts any real-valued vector curve. | |
| Check Type | changetype | list | positive_to_negative | Direction of the sign change to detect: ‘positive_to_negative’ (default) or ‘negative_to_positive’; selects which zero-crossing polarity triggers an event. | |
| Min Time Window | pretime_window | scalar | 600 | Minimum duration (in curve time units, default 600) over which the sign change must be sustained before it is registered as a valid event. | |
| Max Time Window | posttime_window | scalar | 1200 | Maximum duration (in curve time units, default 1200) allowed for a single event; if the crossing persists beyond this value the detector resets and searches for the next event. | |
| Fluctuation Time Window | fluctuationtimewindowinpercentage | scalar | 2% | Short grace window (expressed as a percentage of the minimum time window, default ‘2%’) within which minor signal fluctuations back across zero are ignored so that noisy crossings are not split into multiple events. | |
| Minimum Cycle Max | minimum_cycle_maxpercentageof_total_max | scalar | 5% | Minimum cycle change in percentage of the sustained max value | |
| Include All Cross-over Points | includeallcross-overpoints | list | no | Include all cross-over points | |
| Zero Value | zerovalue | scalar | 1.0 | Values within -1.0 and 1.0 of this value is considered zero | |
| Project Values Within The Zero Value | projectvalueswithinthezerovalue | list | no | Project points whose y-value fall within the zero value to zero |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_event_detection_sign_change_output_1 | curve_event_detection_sign_change_output_1 | dataset | Dataset table listing each detected sign-change event with its start time, end time, duration, and relevant amplitude statistics extracted from the input curve. |
Disciplines¶
- data.curve.transform
- data.signal_processing
Runnable example¶
A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: /api/workflow/example?id=curve_event_detection_sign_change
Auto-generated from transformation schema. Worker id: curve_event_detection_sign_change. Schema hash: 70fe94dbff4d. Hand-curated docs in workerexamples/ override this page when present.