fn image_space_dipole_kernel(grid: &Grid, b: (f64, f64, f64)) -> Vec<Complex64> ⓘExpand description
dipole_kernel.m’s 'imagespace' kernel: the dipole field
(3 (r·B0)² − |r|²) / (4π |r|⁵) sampled at the voxel positions r (mm), 0 at r = 0, with the
origin at index 0 (fftshift of the -N/2:N/2-1 grid), Fourier transformed.