Struct WhQsmParams 

pub struct WhQsmParams {

    pub alpha1: f64,
    pub mu1: f64,
    pub mu2: f64,
    pub beta: f64,
    pub muh: f64,
    pub max_iter: usize,
    pub tol_update: f64,
    pub tol_delta: f64,
    pub weight: WhQsmWeight,
    pub b0: f64,
    pub echo_times: Vec<f64>,
    pub te: EchoTime,
    pub kernel: FansiKernel,
}

WH-QSM parameters.

Fields

alpha1: f64

TV regularization weight.

mu1: f64

ADMM penalty for the TV splitting (mu).

mu2: f64

ADMM penalty for the data-fidelity splitting.

beta: f64

Weak-harmonic ROI penalty (constrains the harmonic field inside the mask). Default 150, WH_nlTV.m’s own default. FANSI’s demo (script_DICOM_Philips.m l. 432-433) sets beta = 200, muh = 5, as a starting point to “fine tune” (“usually, beta is between 20 to 50 times larger than muh”); the function’s default is kept.

muh: f64

ADMM penalty for the harmonic-field splitting.

max_iter: usize

Maximum outer iterations.

tol_update: f64

Percent-update stopping tolerance on x.

tol_delta: f64

Inner Newton stopping tolerance.

weight: WhQsmWeight

Magnitude normalisation for the data weight.

b0: f64

Field strength in Tesla (scan parameter, for the radian conversion).

echo_times: Vec<f64>

Echo times in seconds, in acquisition order (scan parameter, for the radian conversion).

te: EchoTime

Which echo time the radian conversion uses. Default EchoTime::First. FANSI’s multi-echo example, script_DICOM_Philips.m, scales the field by deltaTE = TE(echo2) - TE(echo1) (FANSI-toolbox 93044a3, line 364) before WH_nlTV (line 436), but with a weight from M0 and the fit noise, and its comment on that line says “You may use also any individual echo time”. With the default flat weight (WhQsmWeight::Flat), the first echo does better: on QSM-CI’s simulated head (7 T, echoes 4/12/20/28 ms, its true local field and mask; FANSI’s kernel, the flat weight over the whole volume, QSM.rs#402) χ NRMSE 33.6 % and r 0.945 at the first echo against 42.0 % and 0.914 at the spacing. (Before QSM.rs#402, with the continuous kernel and the weight only in the mask, the spacing diverged on the qsm-forward phantom, r 0.07, and the first echo gave XSIM 0.754, NRMSE 35.5 %.) With a magnitude weight the echo spacing does better than the first echo (echo-1 magnitude, WhQsmWeight::MaxNormalised; qsm-forward phantom, integration-test settings, FANSI’s kernel, QSM.rs#418; XSIM / NRMSE / r 0.676 / 48.9% / 0.876 vs 0.638 / 49.9% / 0.873; with the continuous kernel, #276: XSIM 0.673 vs 0.637).

kernel: FansiKernel

The dipole kernel. Default FansiKernel::Discrete, FANSI’s dipole_kernel_angulated as the original is run with; FansiKernel::Continuous is the crate’s continuous kernel (see FansiKernel for the decision and the measurements).

Trait Implementations

impl Clone for WhQsmParams

fn clone(&self) -> WhQsmParams

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WhQsmParams

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

Formats the value using the given formatter.

impl Default for WhQsmParams

fn default() -> Self

WH_nlTV.m defaults (mu2 = 1, muh = 5, beta = 150, 150 iterations, tolUpdate 0.1, tolDelta 1e-6). WH_nlTV.m has no default for alpha1; mu1 is its default 100*alpha1.

impl Serialize for WhQsmParams

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

where __S: Serializer,

Serialize this value into the given Serde serializer.