A method is presented which allows us to quantify the information cont
ained in high-resolution electron micrographs by the measurement of th
e intensity of reflections in diffractograms. Due to transfer gaps of
the contrast transfer function and in order to extend the experimental
information, focus series are applied. As final results the imaging p
arameters are determined simultaneously with the amplitudes and phases
of the Fourier components of the exit-surface wave function. The proc
edure is tested using images simulated close to realistic conditions a
nd proven to work. First results from an application to experimental f
ocus series are presented.