Hello,
Is it possible to provide some details of how the calculation is carried out for the following options:
Result Image:
Sigma (average)
Sigma (Add)
Master Images:
Sigma.
Regards,
Patrick.
Preprocessing - Options
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Forum_2016
- Posts: 219
- Joined: 08 Dec 2018, 13:30
Re: Preprocessing - Options
Hello,
Add and Average are almost the same thing (Average is an Add with a final division by N#) but Add is very useful for 8 and 12 bit images where quantization is an issue.
Sigma excludes from the final Average/Sum all those values which are outside the X-sigma rule of thumb,
see: https://en.wikipedia.org/wiki/68%E2%80% ... 399.7_rule, where X is a given parameter (default 1.8).
Sigma is CPU/RAM/Disk intensive since it has to access the same pixel on temporary images at the same time. In most case you can reach the same result with an Hot Pixels filter in Preprocessing (or in Demosaic of Preprocessing) and a classical Average/Add.
Regards,
Fabio.
Add and Average are almost the same thing (Average is an Add with a final division by N#) but Add is very useful for 8 and 12 bit images where quantization is an issue.
Sigma excludes from the final Average/Sum all those values which are outside the X-sigma rule of thumb,
see: https://en.wikipedia.org/wiki/68%E2%80% ... 399.7_rule, where X is a given parameter (default 1.8).
Sigma is CPU/RAM/Disk intensive since it has to access the same pixel on temporary images at the same time. In most case you can reach the same result with an Hot Pixels filter in Preprocessing (or in Demosaic of Preprocessing) and a classical Average/Add.
Regards,
Fabio.
-
Forum_2016
- Posts: 219
- Joined: 08 Dec 2018, 13:30
Re: Preprocessing - Options
Fabio,
Thank you for your quick and clear explanation. Also for the wiki reference.
As I will be using AA6 for preprocessing all my spectra, I do have great interest in understanding how some specific processes work.
My next questions concern (a) Hot Pixels and (b) Alignment. I will pose these questions under separate topics. I also thank you for providing the great Guide on Slit functionality.
Regards,
Patrick.
Thank you for your quick and clear explanation. Also for the wiki reference.
As I will be using AA6 for preprocessing all my spectra, I do have great interest in understanding how some specific processes work.
My next questions concern (a) Hot Pixels and (b) Alignment. I will pose these questions under separate topics. I also thank you for providing the great Guide on Slit functionality.
Regards,
Patrick.
