Struct ResharpParams 

pub struct ResharpParams {
    pub radius: f64,
    pub tik_reg: f64,
    pub tol: f64,
    pub max_iter: usize,
}

RESHARP algorithm parameters.

The defaults are the first author’s code: background_field_removal/resharp.m in github.com/sunhongfu/QSM (c75b138), whose own defaults are ker_rad = 3, tik_reg = 1e-4, iter_num = 200 (l. 24-34) and cgs(@Afun, b, 1e-6, iter_num) (l. 92). Hongfu Sun’s scanner drivers in the same repository override them inconsistently (3T Siemens drivers 3 mm / 1e-3 / 500, Philips 3T 3 mm / 1e-4 / 200, 1.5T and 4.7T drivers 4-5 mm / 5e-4, GE variants 2-4 mm), so the function’s defaults are the reference here; the radius, 3 mm, is also what every 3T driver uses.

Measured against the previous defaults (6 mm, 30 iterations), ROMEO field then RTS, on the voxels both keep: on the qsm-forward phantom χ XSIM 0.283 → 0.303, NRMSE 80.4 → 79.7 %, r 0.597 → 0.606; on an in-vivo 3T Philips scan, agreement with the UK Biobank pipeline’s χ (STI Suite V-SHARP + iLSQR) XSIM 0.647 → 0.688, NRMSE 63.2 → 62.2 %, r 0.833 → 0.838. The 3 mm kernel also keeps ~18 % more voxels at the brain edge, where agreement is lower (in vivo on its own mask, XSIM 0.653, NRMSE 71.1 %). The radius drives the in-vivo gain (3 mm / 30 iterations: 0.727) and the iterations the phantom gain (6 mm / 200: 0.302).

Fields

radius: f64

SMV kernel radius in mm (default 3, resharp.m’s ker_rad); per axis it is round(radius/voxel) voxels, at least 2 (resharp_kernel_radii), so the kernel is an ellipsoid on anisotropic voxels. QSM.rs previously used 6 mm, which had no source.

tik_reg: f64

Tikhonov regularization parameter (default 1e-4, resharp.m’s tik_reg)

tol: f64

Relative residual tolerance of the cgs solve (default 1e-6, as resharp.m passes it)

max_iter: usize

Maximum cgs iterations (default 200, resharp.m’s iter_num), each making two operator calls as MATLAB’s cgs does. QSM.rs previously defaulted to 30, which had no source and stopped well short of the tolerance.

Trait Implementations

impl Clone for ResharpParams

fn clone(&self) -> ResharpParams

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ResharpParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ResharpParams

fn default() -> Self

Returns the “default value” for a type.

impl Serialize for ResharpParams

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.