aug_spline_y_perturb — Smooth additive spline perturbation¶
Group: Augmentation · C ABI: n4m_augmentation_spline_y_perturbations_*
Description¶
Spline y-axis perturbation augmenter.
Parameters¶
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API and bindings¶
C ABI (ABI 2): n4m_augmentation_spline_y_perturbations_apply · n4m_augmentation_spline_y_perturbations_create · n4m_augmentation_spline_y_perturbations_destroy. Use the linked public header for the exact signature, configuration, and result handles.
Python (verified public re-export):
from n4m.augmentation.splines import SplineYPerturbationAugmenter
Source signature: SplineYPerturbationAugmenter(spline_points: int = -1, perturbation_intensity: float = 0.005, rng: Optional[PCG64] = None, seed: int = 0).
R: no current source-verified entry point was found for this catalog method.
MATLAB / Octave: no current source-verified entry point was found for this catalog method.
Explanations¶
Bibliographic source¶
No publication canonically defines this control-point noise augmenter. Its random-control construction is specified by the native source.
Mathematical principle¶
Let \(v=\max(X)\) times perturbation_intensity and draw one batch-shared baseline from \(U(-v,v)\). For every row, draw y offsets at spline_points controls (default \(p/2\), minimum 4) from the baseline-shifted interval, fit a not-a-knot cubic curve on [0,p], evaluate it on channels 0 through p-1, and add that curve to the row.
Appropriate uses¶
Generating smooth additive baseline fluctuations instead of channelwise white noise.
Limits and validation¶
Intensity is tied to the global maximum, not absolute magnitude; all-negative data therefore invert the intended interval. Many controls can approach high-frequency noise, while few reduce the effect to broad drift. The last anchor lies at p, one step beyond the final queried channel p-1.
Implementation¶
Python role API n4m.augmentation.splines.SplineYPerturbationAugmenter; ABI 2 family n4m_augmentation_spline_y_perturbations_{create,apply,destroy}.
The ABI-2 implementation is the n4m_augmentation_spline_y_perturbations_* lifecycle in libn4m.
Sources and provenance¶
See also: methods index · interactive dashboard