# Fourier Shell Correlation

From Dynamo

Revision as of 09:39, 25 April 2016 by Daniel Castaño (talk | contribs)

The Fourier Shell Correlation (FSC) between two volumes is a measure of their similarity. It assigns a coefficient between -1 and 1 to each chosen frequency range.

FSC computations are used in different areas of *Dynamo*

- During adaptive bandpassing, the FSC of the two half averages is used to measure the
*resolution*attained at each iteration. - During a regular project, the FSC between the freshly computed iteration average and the one generated in the previous iteration is also computed. This information is used to measure the
*convergence*.

The command line that computes the FSC is `dfsc`. In its default settings, the FSC for two volumes with a sidelength of *N* pixels would be a vector with a length of "N"/2 pixels.
`
`

- compute A
- compute B

- for each i=1:N/2
- compute a shell
- locate elements of A and B inside shell n(i)

`
The entry [i] in the FSC would be the result of generating a shell in Fourier space
`**Failed to parse (Missing <code>texvc</code> executable. Please see math/README to configure.): i-1<\le r<i**