Module iqfm 

iQFM single-step deep-learning tissue-field mapping (onnx feature).

iQFM (Gao 2022) is the local (tissue) field output of the same network as iQSM — a learnable-Laplacian “LoT” front-end + U-Net that maps raw wrapped MRI phase (radians) straight to the background-removed local field (ppm), folding phase unwrapping and background-field removal into one network. It is the iQFM head of the authors’ repo (weights iQFM_40_v2.pth + LoTLayer_lfs_40_v2.pth), the sibling of the χ head used by [super::iqsm].

The exported graph, the four+border inputs, the preprocessing (phase sign, sphere erosion, centre-pad to /16, mask, crop) and the multi-echo magnitude·TE² combination are identical to iQSM — only the trained weights and the meaning of the output (local field vs susceptibility) differ. So the Rust glue simply runs iQSM’s exact pipeline with the iqfm.onnx bytes.

Weights are not bundled; the caller passes the exported iqfm.onnx bytes.

Functions

iqfm

Run iQFM on a single echo of wrapped phase; returns the local field (ppm), masked, column-major (nx,ny,nz). See super::iqsm::iqsm for the argument semantics — they are shared verbatim (only the network and its output differ).

iqfm_multi_echo

Multi-echo iQFM: reconstruct each echo and combine with magnitude·TE² weights, exactly as super::iqsm::iqsm_multi_echo (the authors’ --echo_4d path).