Difference between revisions of "Cross correlation matrix"

From Dynamo
Jump to navigation Jump to search
Line 7: Line 7:
 
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:
 
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:
 
<code>
 
<code>
 
+
# read particle ''i'' -> Pi
# read particle i  -> Pi
 
 
# rotate and shift particles ''i''
 
# rotate and shift particles ''i''
 
# create the missing wedge of particle
 
# create the missing wedge of particle

Revision as of 10:36, 19 April 2016


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
  2. rotate and shift particles i
  3. create the missing wedge of particle
  4. rotate missing wedge of particles i RiWi
  5. compute Fourier coefficients common to Cij


Input of a ccmatrix

Computation of ccmatrix

Application of a ccmatrix