Combining noisy images of small crystalline domains in high resolution electron microscopy

Abstract

A technique is presented for enhancing and combining electron microscope images of small clystalline areas. Phases obtained by Fourier transforming electron micrographs are merged with available more precise amplitudes, in a Fourier synthesis, to obtain a final estimated image. The procedure is illustrated with 42 individual images of the purple membrane from Halobacterium halobium. To show the power of combination, results based on 1, 2, 4, 8, 16, 32 and 42 images are presented. An estimate based solely on the micrograph data, i.e. ignoring the precise amplitudes, is also presented and is seen to be notably poorer. The level of uncertainty of the final image is assessed by stimulating 10 final images and superposing the results.