Module fieldmap 

Multi-echo phase combination and B0 field mapping.

Building blocks for turning multi-echo wrapped phase into a B0 field map: phase-offset removal (MCPC-3D-S / ASPIRE), weighted B0 estimation, and linear multi-echo fitting.

Structs

CoilCombinationResult

Result of MCPC-3D-S multi-coil combination (mcpc3ds_combine).

LinearFitParams

Parameters for multi-echo linear fit.

LinearFitResult

Result of multi-echo linear fit

PhaseOffsetParams

Parameters for phase offset removal.

Enums

B0WeightType

B0 weighting types matching MriResearchTools.jl

Functions

bipolar_correction

Bipolar gradient correction for multi-echo phase data.

calculate_b0_weighted

Calculate B0 field from unwrapped phase using weighted averaging

field_to_hz

Convert field from rad/s to Hz

gaussian_box_sizes

Box-filter widths approximating a Gaussian of sigma (voxels) with n passes — the getboxsizes of MriResearchTools.jl (Kovesi’s “fast almost-Gaussian” construction). Returns all-ones (i.e. no smoothing) when sigma is not positive.

mcpc3ds_combine

MCPC-3D-S multi-coil phase combination (Eckstein et al., MRM 2018), as in MriResearchTools.jl’s mcpc3ds for 5D (multi-echo, uncombined) input.

multi_echo_linear_fit

Multi-echo linear fit with magnitude weighting

nan_box_smooth_3d

Masked 3D smoothing by repeated NaN-aware box filtering — the mask branch of gaussiansmooth3d! in MriResearchTools.jl (4 passes per axis, alternating direction on even passes, box widths from gaussian_box_sizes). Voxels outside mask become NaN before filtering and are only given values where the filter extrapolates across the boundary; the result is written in place.

nan_box_smooth_3d_phase

Masked phase smoothing via the complex representation, using nan_box_smooth_3d — gaussiansmooth3d_phase(phase, sigma; mask) of MriResearchTools.jl. Returns NaN where the smoothed complex value is undefined (far outside the mask).

phase_offset_removal

MCPC-3D-S phase offset estimation for single-coil multi-echo data