transfer

transfer#

Module to describe the contrast transfer function (CTF) and the related apertures.

Functions

cartesian2polar(cartesian)

Convert between Cartesian and polar aberration coefficients.

hard_aperture(alpha, semiangle_cutoff)

Calculates an array with a disk of ones and a soft edge.

nyquist_sampling(semiangle_cutoff, energy)

Calculate the Nyquist sampling.

point_resolution(Cs, energy)

Calculate the Scherzer point resolution.

polar2cartesian(polar)

Convert between polar and Cartesian aberration coefficients.

scherzer_defocus(Cs, energy)

Calculate the Scherzer defocus.

soft_aperture(alpha, phi, semiangle_cutoff, ...)

Calculates an array with a disk of ones and a soft edge.

Classes

Aberrations([aberration_coefficients, ...])

Phase aberrations.

Aperture(semiangle_cutoff[, soft, energy, ...])

A circular aperture cutting off the wave function at a specified angle, employed in both STEM and HRTEM.

BaseAperture([semiangle_cutoff, energy, ...])

Base class for apertures.

BaseTransferFunction([energy, extent, gpts, ...])

Base class for transfer functions.

Bullseye(num_spokes, spoke_width, num_rings, ...)

Bullseye aperture.

CTF([semiangle_cutoff, soft, focal_spread, ...])

The contrast transfer function (CTF) describes the aberrations of the objective lens in HRTEM and specifies how the condenser system shapes the probe in STEM.

SpatialEnvelope(angular_spread[, ...])

Envelope function for simulating partial spatial coherence in the quasi-coherent approximation.

TemporalEnvelope(focal_spread[, energy, ...])

Envelope function for simulating partial temporal coherence in the quasi-coherent approximation.

Vortex(quantum_number, semiangle_cutoff[, ...])

Vortex-beam aperture.

Zernike(center_hole_cutoff, phase_shift, ...)

Zernike aperture.