Wipe Feature - When to use mask?
Posted: Sun Jul 13, 2014 3:07 pm
When you use wipe, do should you mask the Galaxy/object of interest or leave a mask off.
Hi Waterbourn,waterbourn wrote:When you use wipe, do should you mask the Galaxy/object of interest or leave a mask off.
Use a mask when there is a chance that Wipe might otherwise remove faint nebulosity that is persistent over a greater area (for example a galaxy's halo or in the close up of a nebula).
Wipe searches for a constant background level of brightness around each pixel in the image (the search area is governed by the 'Aggressiveness' setting). If the background level of brightness does not change around the pixel, then Wipe concludes that that pixel must be sitting directly on the background. Making this conclusion, Wipe will remove any 'bias in the signal' in that 'background' so that that pixel will now sit on a nice neutral background.
However, if the pixel sits in in a big area of nebulosity, Wipe may mistakenly think that, since that nebulosity is also nice and constant, the nebulosity is a local 'bias in the signal' that needs to be removed.
To keep Wipe from even looking at the nebulosity, you can mask out the area where the nebulosity is.
So long story short, yes, the more you help Wipe by telling it 'not to bother' in certain areas, the better your result will be.
Hope this helps!