aug_particle_size — Particle-size and path-length scatter heuristic

Group: Augmentation · C ABI: n4m_augmentation_particle_size_*

Description

Particle-size and path-length scattering simulation.

Parameters

Name	Type	Default
mean_size_um	float	50.0
size_variation_um	float	15.0
use_size_range	bool	False
size_range_low_um	float	5.0
size_range_high_um	float	500.0
reference_size_um	float	50.0
wavelength_exponent	float	1.5
size_effect_strength	float	0.1
include_path_length	bool	True
path_length_sensitivity	float	0.5
wavelengths	—	None
rng	Optional[PCG64]	None
seed	int	0

API and bindings

C ABI (ABI 2): n4m_augmentation_particle_size_apply · n4m_augmentation_particle_size_create · n4m_augmentation_particle_size_destroy. Use the linked public header for the exact signature, configuration, and result handles.

Python (verified public re-export):

from n4m.augmentation.scattering import ParticleSizeAugmenter

Source signature: ParticleSizeAugmenter(mean_size_um: float = 50.0, size_variation_um: float = 15.0, use_size_range: bool = False, size_range_low_um: float = 5.0, size_range_high_um: float = 500.0, reference_size_um: float = 50.0, wavelength_exponent: float = 1.5, size_effect_strength: float = 0.1, include_path_length: bool = True, path_length_sensitivity: float = 0.5, wavelengths = None, 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 single paper defines this simulator. It is physically motivated by diffuse scattering but uses an explicit empirical power law documented in the source, not a Mie or Kubelka–Munk solver.

Mathematical principle

Draw a particle size \(d_i\) from the configured uniform range or a normal law clipped to 5–500 µm. With \(r_i=d_i/d_0\) and \(w(\lambda)=\operatorname{clip}(\lambda/1500,0.1,10)^{-e}\), add the zero-mean baseline \(s(r_i^{-1/2}-1)w(\lambda)\). Optionally multiply by \(\operatorname{clip}[1+p\log r_i,0.7,1.5]\) and add smoothed Gaussian scatter noise.

Appropriate uses

Qualitative robustness studies for powders with particle-size and path-length variation.

Limits and validation

The coefficients and power law are heuristic; wavelengths are required and assumed compatible with the 1500-unit scale. It should not be used for quantitative optical simulation.

Implementation

Python role API n4m.augmentation.scattering.ParticleSizeAugmenter; ABI 2 family n4m_augmentation_particle_size_{create,apply,destroy}.

The ABI-2 implementation is the n4m_augmentation_particle_size_* lifecycle in libn4m.

Sources and provenance

https://github.com/GBeurier/nirs4all-methods/blob/main/cpp/src/core/augmentation/scattering/particle_size.h

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