Enhanced EUV Corona (Radial Filter)

Enhanced EUV Corona, or radial filter, processing is a technique developed at SAO to enhance the contrast of off-limb features in AIA images. This brings out features that are faint or poorly-resolved using the standard scaling and allows for a more detailed picture of coronal dynamics.

To see some examples of movies created using the radial filter software, follow the "Movies" link in the left navigation bar. Click "Software" for information on acquiring and using the code.

To get a sense for how various AIA passbands behave when processed in this way, below is a side-by-side comparison of unprocessed and radially filtered images. The "best" AIA channel for this application seems to be the 171 Angstrom passband because it tends to be visible at greater distances from the disk than the others. However, as is apparent below, the radial filter can also bring out structures in the other channels not readily apparent using conventional scaling.

  Unprocessed   Artificial Coronagraph
  171   171_rfilter
171 Å Channel on 2011/11/05 @ 00:30 UT
  193   193_rfilter
193 Å Channel on 2011/11/12 @ 00:01 UT
  211   211_rfilter
211 Å Channel on 2011/11/07 @ 04:30 UT
  304   304_rfilter
304 Å Channel on 2011/08/17 @ 03:36 UT
  131   131_rfilter
131 Å Channel on 2011/08/17 @ 02:24 UT
  1600   1600_rfilter
1600 Å Channel on 2011/08/17 @ 03:58 UT

Section Photo

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171 Å Enhanced Corona image taken on 2011/11/09.

Section Photo