High resolution micrographs are often of poor quality, due to various distortions and especially to a very low signal-to-noise ratio. Visual quality can be improved significantly by using correlation-averaging techniques to combine several observations of similar subjects. We had previously developed methods for translational and rotational alignment of different views of ostensibly identical specimens. These techniques have been extended for the compensation of spatial deformations in slightly distorbed periodic structures. Multivariate statistical techniques have been implemented for the analysis and comparison of sets of images. Quantitative approaches have been developed for the automated removal of anomalous views and the assessment of spatial properties of the resulting averaged image (e.g., rotational symmetry and resolution). These methods have been applied successfully to structure determination and quantitative assessment of Herpes Simplex type II Virus capsomers, T7 Virus, and skeletal muscle filament images.
