pp_piecewise_msc — Piecewise multiplicative scatter correction¶
Group: Signal transforms · C ABI: n4m_transform_piecewise_msc_*
Description¶
Apply MSC independently inside fixed wavelength intervals.
Parameters¶
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API and bindings¶
C ABI (ABI 2): n4m_transform_piecewise_msc_create · n4m_transform_piecewise_msc_destroy · n4m_transform_piecewise_msc_fit · n4m_transform_piecewise_msc_is_fitted · n4m_transform_piecewise_msc_transform. Use the linked public header for the exact signature, configuration, and result handles.
Python (verified public re-export):
from n4m.transform.scatter import PiecewiseMSC
Source signature: PiecewiseMSC().
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 single paper canonically defines this fixed-window variant. It applies the MSC model of Geladi, MacDougall & Martens (1985), https://doi.org/10.1366/0003702854248656, independently by interval.
Mathematical principle¶
The wavelength axis is partitioned into non-overlapping windows. Within each window and row, local intercept and slope are estimated against the corresponding reference segment, and every value in that window is corrected by \((x-a)/b\).
Appropriate uses¶
Scatter correction when gain and offset differ between broad spectral regions.
Limits and validation¶
Independent windows can create discontinuities and short or flat segments make slopes unstable. The reference is training-dependent and the method can remove regional chemical amplitude differences.
Implementation¶
n4m.transform.scatter.PiecewiseMSC wraps n4m_transform_piecewise_msc_*; reference fitting and segment OLS are in cpp/src/c_api/c_api_advanced.cpp.
The ABI-2 implementation is the n4m_transform_piecewise_msc_* lifecycle in libn4m.
Sources and provenance¶
https://doi.org/10.1366/0003702854248656; https://github.com/GBeurier/nirs4all-methods/blob/main/cpp/src/c_api/c_api_advanced.cpp
See also: methods index · interactive dashboard