pp_piecewise_direct_standardization — Piecewise direct standardization (PDS)¶
Group: Signal transforms · C ABI: n4m_domain_adaptation_piecewise_direct_standardization_*
Description¶
PDS: local regressions mapping source windows to target wavelengths.
Parameters¶
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API and bindings¶
C ABI (ABI 2): n4m_domain_adaptation_piecewise_direct_standardization_create · n4m_domain_adaptation_piecewise_direct_standardization_destroy · n4m_domain_adaptation_piecewise_direct_standardization_fit · n4m_domain_adaptation_piecewise_direct_standardization_is_fitted · n4m_domain_adaptation_piecewise_direct_standardization_transform. Use the linked public header for the exact signature, configuration, and result handles.
Python (verified public re-export):
from n4m.domain_adaptation.standardization import piecewise_direct_standardization
Source signature: piecewise_direct_standardization(X_source, X_target, X = None, window_size: int = 5, fit_intercept: bool = True, ridge: float = 0.0).
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¶
Bouveresse & Massart (1996), Improvement of the piecewise direct standardization procedure for the transfer of NIR spectra for multivariate calibration, Chemometrics and Intelligent Laboratory Systems 32, 201–213, https://doi.org/10.1016/0169-7439(95)00074-7.
Mathematical principle¶
For target wavelength \(j\), PDS fits a local affine regression from a source window around \(j\) to the paired target value at \(j\). The fitted local coefficients form a banded transfer map; optional ridge regularization stabilizes each window solve.
Appropriate uses¶
Instrument transfer when wavelength-local response differences make one dense global DS map unnecessarily flexible.
Limits and validation¶
Requires aligned paired standards. Window width trades locality against conditioning; edge windows differ in size and local linear maps cannot correct nonlinear detector effects.
Implementation¶
n4m.domain_adaptation.standardization.PiecewiseDirectStandardization uses n4m_domain_adaptation_piecewise_direct_standardization_*; window regressions are implemented in cpp/src/c_api/c_api_advanced.cpp.
The ABI-2 implementation is the n4m_domain_adaptation_piecewise_direct_standardization_* lifecycle in libn4m.
Sources and provenance¶
https://doi.org/10.1016/0169-7439(95)00074-7; https://github.com/GBeurier/nirs4all-methods/blob/main/cpp/src/c_api/c_api_advanced.cpp
See also: methods index · interactive dashboard