Struct FieldMappingResult 

pub struct FieldMappingResult {
    pub b0_field_ppm: Vec<f64>,
    pub valid_mask: Vec<u8>,
    pub phase_offset: Option<Vec<f64>>,
    pub robust_fit: Option<RobustFitReport>,
    pub reliability: Option<Vec<u8>>,
    pub qsmart_fit_threshold: Option<f64>,
    pub field_noise_ppm: Option<Vec<f64>>,
    pub complex_fit: Option<FitPpmComplexResult>,
}

Results from field mapping stage

Fields

b0_field_ppm: Vec<f64>

B0 field map in ppm; 0 outside valid_mask (inside mask).

valid_mask: Vec<u8>

Where the field is defined: the brain mask passed in, less the voxels where MCPC-3D-S’s phase offset is undefined (PhaseOffsetRemoval::valid) when phase-offset removal ran; the brain mask itself on every other path. The reference (MriResearchTools’ mcpc3ds → ROMEO.jl → calculateB0_unwrapped) leaves the field NaN there, so later stages (background removal, inversion, referencing) must work in this mask, not in the brain mask.

phase_offset: Option<Vec<f64>>

Phase offset map (if phase offset removal was used); 0 where it is undefined.

robust_fit: Option<RobustFitReport>

What the robust fit found, when B0EstimationMethod::RobustFit combined the echoes; None for every other method.

reliability: Option<Vec<u8>>

QSMART’s reliability map R_0 (1 = reliable), when B0EstimationMethod::QsmartEchofit combined the echoes; None for every other method. Pass it to run_qsmart.

qsmart_fit_threshold: Option<f64>

The blurred echo-fit residual reliability was cut at, when B0EstimationMethod::QsmartEchofit combined the echoes: the percentile’s value for QsmartFitThreshold::Percentile, the value itself for a fixed threshold (echofit.m prints it as “Setting adaptive echo-fit threshold at %2.2f”). None for every other method.

field_noise_ppm: Option<Vec<f64>>

Standard deviation of b0_field_ppm per voxel, in ppm, for the methods that estimate it: B0EstimationMethod::ComplexFit (Fit_ppm_complex.m’s dp1, MEDI’s N_std, which MEDI passes to PDF and MEDI_L1). None for every other method.

complex_fit: Option<FitPpmComplexResult>

MEDI’s complex fit itself, when B0EstimationMethod::ComplexFit made the field map: fit_ppm_complex’s result, before spatial unwrapping. Its field is MEDI’s iFreq_raw (phase per echo spacing, radians, wrapped) and its noise MEDI’s N_std (radians per echo spacing), so a caller that wants them need not run the fit again. None for every other method.