# Difference between revisions of "Fourier Shell Correlation"

From Dynamo

Line 6: | Line 6: | ||

− | The command line that computes the FSC is {{docfunction|dynamo_fsc|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. The entry [i] in the FSC would be the result of generating a shell in Fourier space | + | The command line that computes the FSC is {{docfunction|dynamo_fsc|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. |

+ | <tt> | ||

+ | #compute A | ||

+ | #compute B | ||

+ | |||

+ | #for each i=1:N/2 | ||

+ | #; compute a shell | ||

+ | #; locate elements of A and B inside shell n(i) | ||

+ | |||

+ | </tt> | ||

+ | The entry [i] in the FSC would be the result of generating a shell in Fourier space | ||

<math> i-1<\le r<i</math> | <math> i-1<\le r<i</math> |

## Revision as of 09:39, 25 April 2016

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**