Image integration, ignore black pixels

[georg.viehoever]

Hello.

I would like to convince the ImageIntegration process to ignore black pixels (i.e. pixels in registered images that black after StarAlignment because the unaligned images don#t have data in this region). This would allow to create mosaics. Can this be done? I think the MinMax rejection procedure does something different.

If possible, I would like to combine "Black Rejection" with the other rejection algorithms. An example of the images I would like to integrate is attached below.

Georg

[NKV]

This would allow to create mosaics.

+100 Especially for mosaic.
Juan, please add "Zerro Rejection" in integration algorithms.

1.Images for draft mosaic.


2. Draft Mosaic just for registration images.


3. Registered images from one of sessions. (75% of pixel have zero.)


4. ImageIntegration Average from all sessions.


I think "Zerro Rejection" can solve many problem.
Best regards,
Nikolay.

[georg.viehoever]

Hi Nikolay,
that's exactly what I had in mind. Good to know that I am not alone .

Georg

[NKV]

Georg, it's features available in every other software and MaximDL too... So i not understand why "Ignore black pixel" not available in PixInsight until now...

[Juan Conejero]

Hi Georg and Nikolay,

In first place, Georg, I'm sorry because I missed this thread. The next time I miss something, please strike me!

features available in every other software and xxx too...

Aha, you certainly know how to punch me

Edited: OK, I understand the problem. I'll try to implement this feature in ImageIntegration as soon as possible.

BTW, Nikolay, that's a wonderful mosaic!

[georg.viehoever]

Hi Juan,

no problem. 

I am happy that this was not just another example of my insane ideas   

Georg

[NKV]

Juan, about ImageIntegration > Region Of Interest.
Possible to add button: "From Dynamic Crop"?
Now, without calculator, not ease to enter coordinates of black border.


PS Sorry for big pic.

[Nocturnal]

Hmm, aren't we mixing two different features here? I thought the original request was for image integration (ie. stacking) to reject black pixels so mosaics can be created from registered images. The other request asks for a modification how mosaic creation works, right?

As for the original request the problem I see is that the SNR of the overlapping regions will not be the same as for the regions that don't overlap. The reason is that you have more pixels to average where there's overlap. While there are advantages to having the higher SNR in the overlap areas I'm not sure the resulting mosaic will be what you'd want to have. When I stack with DSS I used to crop to just the area where every frame contributed. Luc implemented the intersection mode I asked him for and now the crop is no longer needed

[NKV]

I'm not sure the resulting mosaic will be what you'd want to have.

SNR... I collected 89x5min Canon 40D 135mm/f5 during many days. My mount is TT320, it's simple one drive and can track about 2 hours. And every 2 hour i must realign composition via DSLR viewfinder to approximate same region. So, I got QTY of very bad overlapped images...
What i should to do? Crop and use only central region or use more? Just look pictures.
Large filed VS SNR : I prefer larger field for big QTY of images. Now it's impossible, because features "Ignore Black" is not available in PixInsight ImageIntrgration.

The fields:



The corner and central region: Other soft   and PI (last one   ).

[georg.viehoever]

Sander,

...As for the original request the problem I see is that the SNR of the overlapping regions will not be the same as for the regions that don't overlap. The reason is that you have more pixels to average where there's overlap. While there are advantages to having the higher SNR in the overlap areas I'm not sure the resulting mosaic will be what you'd want to have. ...

I am aware of the problem of differrent SNR. However, the alternative is to throw away a large part of the images. I just want to have the capability to accept this, because otherwise I just have to throw away large parts of my drift images (which was the original use case for me). I guess NKV with his TT320 has a similar issues with having the central region only.

Georg