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ISIS rejection function when adding images
Posted: Tue Sep 02, 2014 2:01 pm
by Robin Leadbeater
Can anyone tell me what the rejection function does when adding a sequence of images ("Tools", "image processing 2")
- ISIS_addition_rejection.png (6.46 KiB) Viewed 2948 times
Thanks
Robin
Re: ISIS rejection function when adding images
Posted: Wed Sep 03, 2014 12:05 am
by Christian Buil
It is the parameter of a sigma-clipping algorithm for reject deviant values during addition process (for very noisy data, in normal work, do not slect the option). Adjust by successive trial.
Christian
Re: ISIS rejection function when adding images
Posted: Wed Sep 03, 2014 1:03 am
by Robin Leadbeater
Hi Christian,
Just checking that I understand this correctly.
The function looks at the distribution of values in all the exposures for each pixel position and rejects any outliers at each position. (This would for example eliminate cosmic ray hits)
similar to the IRIS sigma clipping function for example
http://www.astrosurf.com/buil/iris/tuto ... 121_us.htm
Is this correct?
Is this function different from the cosmic ray filter in the general tab ?
Thanks
Robin