A new phase consistency criterion and its application in electron crystallography

In this work, we present the principles and potential advantages of a metho dology to assess Fourier components in terms of phase consistency. We defin e a new phase consistency criterion among sets of spatially translated imag es based upon a novel conception of the spatial shift property of the Fouri er transform. The article shows how this criterion can be used in the align ment stage of the 3D reconstruction process with a two-fold objective: Asse ssment of the frequency components and robustness in the alignment. In that sense, the article shows and analyzes the results obtained from the applic ation of the new index of quality in the context of projection image alignm ent. We have focussed our attention on the electron crystallography field, by applying such a phase consistency definition over image reflections. The results that have been obtained show that the new phase-consistency defini tion may complement the traditional SNR-based index of quality (commonly kn own as IQ) of reflections. As a consequence, the reliability of the alignme nt may be improved by discarding those reflections judged as non-reliable a ccording to the phase-consistency criterion. (C) 2000 Elsevier Science B.V. All rights reserved.