Some statistical aspects of low-dose electron imaging of crystals

Abstract The concern is with improving images of molecular structures obtained by biophysicists employing electron microscopes. The phases obtained by Fourier transforming electron micrographs are combined with available more precise amplitudes, in a Fourier synthesis, to obtain images. A study is made of the merits of various multipliers (convergence factors) employed in the Fourier synthesis. An estimate of the error of the improved image is constructed. A method of combining images from different experiments is developed. A noise corrupted version of a high-resolution two-dimensional image of bacteriorhodopsin is employed to visually and formally assess the relative merits of different multipliers.