Mosaic pattern appearing on processed lunar frames

[JoshHopk]

Hello all,

This is my first post on SL, so please correct me if I have started this topic in the wrong place. I am also relatively new to astrophotography, so please ignore my naivety!

I had some clear skies last week, so decided to do some lunar imaging with my new(ish) ASI224MC. I captured my frames in SharpCap as RAW24 AVI files, stacked in AS!2 and processed in Registax and Photoshop. When i got to sharpening in Photoshop, I noticed a sort of mosaic pattern over the image, which took away from some of the detail, and really ruined the image the more I sharpened. I did a quick search and it turned up with 'debayering'. This is a completely new concept to me and all of my attempts didn't seem to improve the image at all (perhaps I was debayering in the wrong order?). I have attached some images and also my some of my SharpCap settings in case they are of help.  

COLOUR SPACE: RAW24

CAPTURE ARE: 1304x976

OUTPUT FORMAT: AVI files (*.avi)

EXPOSURE: 0.29ms

GAIN: 282

Thank you in advance

Regards, Josh.

 

[Cornelius Varley]

Debayering should done at the time of stacking. An alternative method is to run the avi file through PIPP and select the debayering option for the output file.

[vlaiv]

Hi and welcome to SGL and yes, I believe this is related to debayering - or particularly wrong bayer matrix order used.

RGGB should be proper order, but this also depends on other things - like if software used reads frames "bottom/up" or "top/down" (don't ask - strange convention that screen space is top/down - positive Y direction is down, while file space is, like regular coordinates with positive axis going up and sometimes software developers don't pay attention to this or choose to disregard this for simplicity).

 

[JoshHopk]

4 minutes ago, Cornelius Varley said:

Debayering should done at the time of stacking. An alternative method is to run the avi file through PIPP and select the debayering option for the output file.

Thanks, I was very confused as to what order to do this in. I installed PIPP a while back but haven't really used it yet. Thanks for your advice, I'll give it a go!

[CraigT82]

Do you mean RGB24? I didn't think there was a RAW24? 

If I remember correctly RGB24 means that the camera itself is doing the debayering. You really want to capture in RAW and debayer during the post processing. 

[JoshHopk]

3 minutes ago, vlaiv said:

Hi and welcome to SGL and yes, I believe this is related to debayering - or particularly wrong bayer matrix order used.

RGGB should be proper order, but this also depends on other things - like if software used reads frames "bottom/up" or "top/down" (don't ask - strange convention that screen space is top/down - positive Y direction is down, while file space is, like regular coordinates with positive axis going up and sometimes software developers don't pay attention to this or choose to disregard this for simplicity).

 

Wow! I don't think I will ask; that sounds most confusing. I'll ensure to have a look at which bayer matrix order I use when processing. Thanks for the reply!

[JoshHopk]

5 minutes ago, CraigT82 said:

Do you mean RGB24? I didn't think there was a RAW24? 

If I remember correctly RGB24 means that the camera itself is doing the debayering. You really want to capture in RAW and debayer during the post processing. 

Yes, sorry I do mean RGB24. I'll be sure to capture in RAW next time I get some clear skies. Thank you

[JoshHopk]

Thanks all for the fast responses and the warm welcome to SGL. So, to recap: I should capture in RAW and debayer (using RGGB as the bayer matrix order) before stacking in PIPP, or whilst stacking in AS!2.

Thanks again, Josh

[CraigT82]

If you use AS3! It can handle much larger files (no need to use pipp to shorten captures) and you shoot in Raw mode It should automatically detect the bayer pattern and debayer the frames correctly. 

[JoshHopk]

6 minutes ago, CraigT82 said:

If you use AS3! It can handle much larger files (no need to use pipp to shorten captures) and you shoot in Raw mode It should automatically detect the bayer pattern and debayer the frames correctly. 

Okay, thanks. I’ll install AS!3 and use it next time.