Experimental design of exit wave reconstruction from a transmission electron microscope defocus series

Recently published methods reconstruct the complex exit wave of the specimen in a transmission electron microscope (TEM) by combining a number of images recorded at different defocus values. The imaging model for a TEM is in principle nonlinear, but it may be linearized for a wide range of specimens. This linearization is used. Because the pixel intensities of the recorded image are Poisson variates, the reconstruction problem has to be viewed as a statistical parameter estimation problem. An expression is derived for the variance of the reconstructed wave as a function of the experimental parameters that can be freely chosen. It is shown how these parameters can be used for experimental design, that is for the minimizing of the variance of the reconstructed wave