Author Topic: Image Integration Process - Setting Sigma Clipping sliders  (Read 3912 times)

Offline Niall Saunders

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Juan,

When using, for example Winsorized Sigma Clipping, I wonder whether it would be more convenient to be able to set a slider such that a 'desired number' or 'desired percentage' of pixels eventually end up in the High/Low clip images.

It is not necessarily intuitive to decide 'where' to set the Sigma sliders to.

Sure, I was able to tweak the 'High Sigma' slider the other day, such that I totally eliminated a whole bunch of cosmic ray strikes from my integrated master dark - and these strikes were totally invisible in the source darks, and were also invisible when Sigma High was set too low.

Would it not be possible to set a desired 'amount in the dustbin' level, and to then have PixInsight (iteratively) work out the required Sigma multiplier needed to achieve this?

Further,

Can you give us a brief explanation of what the ADU values observed in the Clipping Images actually represent?

I felt, last night, that these were not just simply '0.000' or '1.000', where '1' represented a pixel that 'had been' clipped, from 'at least' one of the source images.

Does the ADU value represent a 'counter', for example, which increments for every image in the dataset that had that particular pixel fall into the 'outlier' category, and thus required to be 'clipped'?

Cheers,
Cheers,
Niall Saunders
Clinterty Observatories
Aberdeen, UK

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Offline mmirot

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Re: Image Integration Process - Setting Sigma Clipping sliders
« Reply #1 on: 2010 January 29 10:21:55 »
I think the process consul gives a number of rejected pixels( %?) for each Image as integrates .
 I don't have much detail on how to interpret the output.

( I would be nice if someone could post a few notes. Perhaps an annotated screen shoot. I am not sure the difference of SNR and SNR steps too )

However, looking at the high low rejection map is still the best way.

Max