DETECT SIGN CHANGES BASED ON 3RD DERIVATIVE SIGN CHANGE¶
Detects sign-change events on a curve by analysing the nth-order derivative (default 3rd) and flagging inflection-like transitions whose magnitude exceeds a user-defined ratio threshold. Use this worker to locate phase reversals, oscillation peaks, or inflection events in time-history or spatial curves.
When to use¶
Classification: process.
Tagged: 3rd_derivative, curve_analysis, derivative, event_detection, inflection, sign_change, time_history.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Curve | curve | vector | — | Input curve (x/y vector pair) on which sign-change events will be detected; must be a well-sampled, continuous time-history or spatial curve. | |
| Order | order | scalar | 3 | Integer order of the derivative used for sign-change detection (default 3 for 3rd derivative); increase to detect higher-frequency inflections, decrease for smoother signals. | |
| Ratio | ratio | scalar | 0.75 | Dimensionless sensitivity threshold in the range (0, 1] that filters candidate sign changes — lower values (e.g. 0.5) capture more events, higher values (e.g. 0.9) retain only the most prominent transitions; default is 0.75. |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_event_detection_derivative_sign_change_output_1 | curve_event_detection_derivative_sign_change_output_1 | vector | Output curve (x/y vector) containing only the detected sign-change event points extracted from the input curve, suitable for downstream annotation or further analysis. |
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_derivative_sign_change
Auto-generated from transformation schema. Worker id: curve_event_detection_derivative_sign_change. Schema hash: c88c25586f49. Hand-curated docs in workerexamples/ override this page when present.