Confidence limits for resolution estimation in image averaging by random subsampling

In this communication we present an empirical approach to the task of estimating the reproducible limit of resolution that can be achieved when a set of images is averaged. The proposed solution is based on a random subsampling method. We derive confidence limits for two of the most widely used measures of reproducibility in this field, the differential phase residual (DPR) and the Fourier ring correlation (FRC). Results both for negatively stained specimens and for those embedded in ice are presented. Our results provide a common framework that allows a number of previous observations and suggestions regarding these measures to be further analyzed.