From wave aberration function, in STEM the wavefunction after aberration consideration can be calculated. The wavefunction affected by the aberrations is the inverse Fourier transform of the aperture function A(k) in the back focal plane, including the phase change due to aberrations and an aperture. Therefore, the wavefunction in the back focal plane is given by,
k -- The two dimensional vector in the back focal plane
Note that the off-axis aberrations are negligible in the case of high-resolution TEM imaging and STEM .
 S. Uhlemann, M. Haider, Ultramicroscopy 72 (1998) 109.