command preprocess: how to define hot sigma

with GUI I can set the hot sigma value to avoid a large number of hotpixels (here 237.760px)

but inside a script, sigma is a constant by 3?

preprocess light -dark=dark_stacked -cfa -debayer
Reading sequence file `light_.seq’.
bitpix for the sequence is set as 20
log: Reading FITS: file dark_stacked, 1 layer(s), 5496x3672 pixels
log: Preprocessing…
Memory per image: 76 MB. Max memory: 5569 MB
log: 237760 corrected pixels (0 + 237760)

PS: I know the commands, but does that solve my problem?

preprocess light -dark=dark_stacked
seqfind_cosme_cfa pp_light_ 3 5
preprocess cc_pp_light_ -debayer

Hello.

So far there is no way to change the cosmetic correction through master dark behavior by command line.
You need to do it manually.

The “preprocess -cfa” works great and it was more of a theoretical question.
Unfortunately you didn’t explain the difference between “seqfind_cosme_cfa” and “preprocess -cfa” to me.

I want to give you some more feedback:
I use an ASI183MC CFA non cooled camera and there are also some hot pixel clusters.
While Siril removes them automatically, not even Pixinsight does it automatically (i.e. without DefectMap)

see this sample of 10 Lights and 10 Darks (Gain 200, 60 seconds, 25°C sensor)


top line are single images (RGB corrected with DarkFrame)
bottom line are stacks of 10 images
Bold is the regular Siril workflow

(1) single frame of ASI183MC, not debayered raw cfa image

(2) Image (1) processed with Siril commands (DeBayer RCD)
preprocess light -dark=dark_stacked
seqfind_cosme_cfa pp_light_ 3 3
preprocess cc_pp_light -debayer

(3) Image (1) processed with Siril command (DeBayer RCD)
preprocess light -dark=dark_stacked -cfa -debayer

(4) Image (1) processed with PixInsight Weighted Batch Preprocessing (WBPP, DeBayer VNG) and CosmeticCorrection (Auto Detect Hot Sigma=3, Cold Sigma =3)

(5) Siril Stack of 10 Images from (2)
stack r_bkg_pp_cc_pp_light rej 3 3 -norm=addscale -out=…/result

(6) Siril Stack of 10 Images from (3)
stack r_bkg_pp_light rej 3 3 -norm=addscale -out=…/result

(7) PixInsight stack of 10 Images from (4) with WBPP


my comment:
(5) You can clearly see that seqfind_cosme_cfa generates darker correction pixels. If you stack more images, the effect becomes even more pronounced. The pixel cluster was not removed well.

(6) Everything is great.

(7) The pixel cluster was not removed well. These green spots are even more noticeable with larger stacks.

Sorry, my bad.

preprocess -cfa

is the command for preprocessing. A cosmetic correction will be applied only if a dark file is loaded. Indeed, in this case, siril checks for hot and cold pixels in the master dark and fix them in the light file. With the command line only hot pixels are fixed.

seqfind_cosme_cfa

This command is a self function that don’t need anything but the lights. Hot and cold pixels are automatically detected and fixed.

Thank you for your feedback. If I understand well, Siril fixes your bad pixels very well if you don’t use the the seqfind_cosme_cfa function. This iswhy I removed the original script files that were using these functions. They are difficult to use.

Cheers,

yes, this command works better as PixInsights autodetect
preprocess light -dark=dark_stacked -cfa -debayer

thanks for great support

1 Like