CLEAN ideas

The family of CLEAN algorithms is based on the a priori assumption that the sky intensity distribution is a collection of point sources. The algorithms have three main steps

Initialization

• of the residual map to the dirty map;
• and of the clean component list to a NULL (i.e. zero) value.

Iterative search

for point sources on the residual map. As those point sources are found,

• they are subtracted from the residual map;
• and then they are logged in the clean component list.

Restoration

of the clean map 1) by convolution of the clean component list with the clean beam, i.e. a Gaussian whose size matches the synthesized beam size and 2) by addition of the residual map.