Propagation And Planning

These functions and classes cover propagation method selection, concrete propagators, and the low-level NA helper.

plan_propagation	Plan a propagation layer for a given field sampling regime.
ASMPropagator	Angular Spectrum Method (ASM) propagator.
RSPropagator	Rayleigh–Sommerfeld propagator via convolution with the RS impulse response.
KSpacePropagator	Diagonal k-space propagator using the angular-spectrum phase advance.
critical_distance_um	Compute the critical propagation distance separating the ASM and RS regimes.
select_propagator_method	Select the recommended propagation method for a given distance.
recommend_nyquist_grid	Build a padded, Nyquist-safe propagation grid.
build_na_mask	Build a hard NA cutoff mask in spatial-frequency coordinates.