Cross correlation matrix

From Dynamo
Revision as of 10:35, 19 April 2016 by Daniel Castaño (talk | contribs)
Jump to navigation Jump to search


The cross correlation matrix (often called ccmatrix in Dynamo jargon) of a set of N particles is an N X N matrix. Each entry (i,j) represents the similarity of particles i and j in the data set.

Definition of similarity

This similarity of particles i and j measured in terms of the normalized cross correlation of the the two aligned particles, filtered to their common fourier components, and restricted to a region in direct space (indicated by a classification mask). The pseudo code will run as:

  1. read particle i -> Pi
  1. rotate and shift particles i
  1. create the missing wedge of particle
  2. rotate missing wedge of particles i RiWi
  3. compute Fourier coefficients common to Cij


Input of a ccmatrix

Computation of ccmatrix

Application of a ccmatrix