shellify

mrinufft.trajectories.tools.shellify(trajectory_func, Nc, nb_shells, z_tilt='golden', hemisphere_mode='symmetric', **traj_kwargs)

Stack 2D or 3D trajectories over the \(k_z\)-axis to make a sphere.

Parameters:

• trajectory_func (function) – Trajectory function that should return an array-like with the usual (Nc, Ns, Nd) size.

• Nc (int) – Number of shots to use for the whole spherically stacked trajectory.

• nb_shells (int) – Number of shells of distorded trajectories.

• z_tilt (str, float, optional) – Tilt of the shells, by default “golden”.

• hemisphere_mode (str, optional) – Define how the lower hemisphere should be oriented relatively to the upper one, with “symmetric” providing a \(k_x-k_y\) planar symmetry by changing the polar angle, and with “reversed” promoting continuity (for example in spirals) by reversing the azimuth angle. The default is “symmetric”.

• **kwargs – Trajectory initialization parameters for the function provided with trajectory_func.

Returns:

Concentric shell trajectory.

Return type:

array_like