In this paper a contribution to the analytical and numerical treatment of the election optical imaging is given, valid for the conditions of the Fresnel approximation. The concept of transmission and propagation functions is used according to the successive steps of the optical imaging process. The computer simulation of electron microscopical phase contrast is carried out for chlorinated Cu-phthalocyanine and Y-Al-garnet. A program system was written in ALGOL-60 for a BESM-6 computer for calculations of two-dimensional Fourier transforms, of appropriate contrast transfer and filter functions as well as of the graphical representation of the results (halftone pictures). The simulation can be done using a simple point model of the object or the complete kinematical structure factors calculated for the crystal plane desired. Molecular images are computed with varying image parameters for accelerating voltages of 500 and 100 kV, respectively. © 1979 North-Holland Publishing Company.
