Jump to content

Narrowband

color camera processing


Recommended Posts

Hey,

I just got the QHY247C camera and have run problems I had in no way expected. The biggest problem is that all software apparently is made for mono cameras, so no matter what I throw at them, it just spits out what is essentially a mono image. So in DSS I found the magic setting:

DSS_magic_setting.png.fb2afc8b8f12ae890ac3984ef4cf2105.png

Now, by suggestion I have tried AstroArt demo version, which seems like a very fast stacker, but I cannot for the life of me comprehend how to get color channels separated. The second problem with AA is that it insists on having focus while stacking, which is something I could get extremely physical with the developer for if I met them IRL. 

So, questions for the color mob:

1: What stacker do you use?

2: which exact settings do you use to stack your pictures?

3: Which tool do you use to post process?

 

Link to comment
Share on other sites

Hi. Can you post a link to the stack?  The DSS settings look fine, so the stack should contain colour data. How have you processed it after stacking? 

1. DSS

2. Default with dithered light plus flat and bias frames only. K-Sigma algorithm.

3. Gimp and or StarTools.

HTH

Link to comment
Share on other sites

I have an Atik 320e which I bought as a replacement for a colour modified Starlight Xpress MX716. I also had problems colour converting at first. Most Astro imaging software show a mono image which will have a small grid over the whole image, th Bauer matrix. I found the easiest way to colour conver was in Astroart4. I've not used it for a while but there is a colour extraction setting where you tell it it's RGB and the match the pattern displayed. This enables setting of offsets as sometimes the bayer matrix is in a different position. Once you've adjusted the offsets the software remembers them and when you stack and calibrate in preprocessing it debayers at the right time in the process. I think the process is principally the same in the current AstroArt. If you debayer at the wrong stage you lose the matrix and colour info,

The reason I'm a bit rusty in AstroArt is that I now us Maxim Dl which has a similar way of setting the bayer matrix and offsets.

i only switched from AstroArt because there wasn't a correct driver for my newer camera.

I hope that helps a bit. Once you've done it successfully in one piece of software you'll begin to understand what's happening.

Anne

 

Link to comment
Share on other sites

18 minutes ago, alacant said:

Hi. Can you post a link to the stack?  The DSS settings look fine, so the stack should contain colour data. How have you processed it after stacking? 

1. DSS

2. Default with dithered light plus flat and bias frames only. K-Sigma algorithm.

3. Gimp and or StarTools.

HTH

As posted, I managed to get a proper image out of DSS, I just find there are other nuances of DSS which frustrate me, such as the never ending crashes running out of memory. Thus I would like to try other tools, but it's so incredibly frustrating how convoluted they tend to be. Hence the request for exact settings.

15 minutes ago, Anne S said:

I have an Atik 320e which I bought as a replacement for a colour modified Starlight Xpress MX716. I also had problems colour converting at first. Most Astro imaging software show a mono image which will have a small grid over the whole image, th Bauer matrix. I found the easiest way to colour conver was in Astroart4. I've not used it for a while but there is a colour extraction setting where you tell it it's RGB and the match the pattern displayed. This enables setting of offsets as sometimes the bayer matrix is in a different position. Once you've adjusted the offsets the software remembers them and when you stack and calibrate in preprocessing it debayers at the right time in the process. I think the process is principally the same in the current AstroArt. If you debayer at the wrong stage you lose the matrix and colour info,

The reason I'm a bit rusty in AstroArt is that I now us Maxim Dl which has a similar way of setting the bayer matrix and offsets.

i only switched from AstroArt because there wasn't a correct driver for my newer camera.

I hope that helps a bit. Once you've done it successfully in one piece of software you'll begin to understand what's happening.

Anne

 

I've read about the offsets, but beyond "try settng it to these values", I have no idea what it means. And I'm not keen on just trial and error without some understanding of why I need to do it. What is this offset? Where can I find the correct offset for my camera? How do I set it in the tool?

Link to comment
Share on other sites

4 minutes ago, Datalord said:

Thus I would like to try other tools, but it's so incredibly frustrating how convoluted they tend to be

Yeah. I tried the trial versions of pixinsight and nebulosity. The simplicity of DSS, which produces excellent stacks without having to jump through hoops, for me at least wins every time. 

The only time I've come across memory issues with DSS is when using drizzle. That said, any software which has to deal with current raw file sizes needs a top end gaming machine to run in real time.

Good luck and don't let this stop you collecting snaps under the stars!

Link to comment
Share on other sites

I have a top end gaming machine with 32gb ram. That's not the issue with DSS. problem is that they are not a 64 bit app, which I can't for the life of me comprehend. And I have 24mp files from this camera, so I have to get a different tool... :-( 

Link to comment
Share on other sites

9 hours ago, Datalord said:

I have a top end gaming machine with 32gb ram.

Nice problems! No seriously, I don't think there are short cuts to be had. Whichever route you go beyond DSS, it'll be a case of learning the reasons for stacking and what each type of frame does. Do post when you make a decision. Cheers and clear skies.

Link to comment
Share on other sites

On 9/3/2017 at 08:12, alacant said:

Nice problems! No seriously, I don't think there are short cuts to be had. Whichever route you go beyond DSS, it'll be a case of learning the reasons for stacking and what each type of frame does. Do post when you make a decision. Cheers and clear skies.

Well [removed word]. Thanks for telling me the ugly truth, though. Now I just have to do research...

Link to comment
Share on other sites

On 02/09/2017 at 22:27, Datalord said:

Hey,

Now, by suggestion I have tried AstroArt demo version, which seems like a very fast stacker, but I cannot for the life of me comprehend how to get color channels separated. The second problem with AA is that it insists on having focus while stacking, which is something I could get extremely physical with the developer for if I met them IRL. 

 

I don't know what you mean by 'having focus while stacking.'

As Anne says, you have to use the 'CCD Colour Synthesis' menu to set the correct Bayer Matrix pattern but this applies to any debayering programme. I took a picture of our kitchen and tried the various Bayer pattern offsets (there are not many) till I got a sensible result. Then it's done forever.

Olly

Link to comment
Share on other sites

2 hours ago, ollypenrice said:

I don't know what you mean by 'having focus while stacking.'

Start the stacking process, switch to watch youtube or read news site, puff, AA decides to come on top of it. On. Every. Image.

2 hours ago, ollypenrice said:

As Anne says, you have to use the 'CCD Colour Synthesis' menu to set the correct Bayer Matrix pattern but this applies to any debayering programme. I took a picture of our kitchen and tried the various Bayer pattern offsets (there are not many) till I got a sensible result. Then it's done forever.

Ok, I found the colour synthesis burried in the Demosaic RGB option.

AA_preprocessing.thumb.png.efbf99416589dd161e04fed4a565db2a.png

AA_demosaic_options.thumb.png.8bc1cd26f06ff6f92bb5133223be679a.png

As you see from the above, it's completely unable to figure out any suggestion for the pattern of the camera. I guess I can look that up.

From what I can tell, the only option to tune on is the Saturation in the Color Synthesis box. That's something I could do in post anyway, so that seems a bit irrelevant. Do I understand you correct that I should tune the white balance parameters until I find the exact parameters matching my camera by virtue taking a proper daylight image?

AA_demosaic.png

EDIT: This image from the manual I wanted to delete from the post, but that turned impossible. So enjoy that picture too... :-)

Link to comment
Share on other sites

On 9/2/2017 at 22:23, Datalord said:

I've read about the offsets, but beyond "try settng it to these values", I have no idea what it means

I read about this some time ago, from memory it's the XY co-ords of the Red pixel in the Bayer square matrix

R  G      Red is at  x = 0, y = 0            G  R      Red is at x = 1, y = 0         G  B                                                   B  G

B  G                                                  B  G                                              R  G   Red is at  x = 0, y = 1                G  R    Red is at x = 1, y = 1

In that example, 0, 0 is the top left corner of the matrix, but different programmes have their own definition of where in the matrix 0, 0 is !!

So in the example below 0, 0  has been defined as bottom left:

R  G   so here  Red is at  x = 1, y = 1,    

B  G

I guess the software code needs numbers not letters.

As Olly suggests, take pictures of your garden at the 4 settings and pick the one that gives the right colour.

Michael

Link to comment
Share on other sites

You probably think I'm being deliberately obtuse but I still don't understand this: 'Start the stacking process, switch to watch youtube or read news site, puff, AA decides to come on top of it. On. Every. Image.' You mean that you can't get AA off the screen, even if you minimize it? Maybe I don't see this because I have two screens, I don't know. I gather Alacant has found the solution, anyway.

I haven't used an OSC camera since, I think, AA4 or maybe 5 and it has changed somewhat. In the mono camera trichromy combining system the white balance now has adjustable parameters whereas previously it was just a tick box, on or off. Until my very last image I got a sensible result if I left it at default but for some reason the last one gave a very odd result. I just accepted it anyway and took it into PI where DBE sorted it out perfectly happily. I don't try to colour balance in AA since I find leaving it to DBE works fine. So I can't help on the white balance parameters. I'll read the manual on this, though.

I was suggesting a daytime photo to find the correct Bayer pattern rather than white balance. It's a long time ago but I think all I did was take a picture of our kitchen (you need a long extender to find close focus but I had one. Failing that a countryside shot would be fine) and then I just tried the alternatives in AA till I got credible colour in the image. It was entirely unambiguous. Alternatively the bayer pattern for the camera should be available on the net. (If you can't find it for the camera you might find it for the chip.)

Olly

Link to comment
Share on other sites

  • 1 month later...

After two months of clouds I got some time to shoot this week. I got some beautiful shots of Orion and Pleiades, colorful and pretty. 

Yesterday, however, APT decided to ignore my 1x1 bin command and took my two hours on the Flaming star nebula in 2x2. And the same mayhem erupted with loss of colour as I had when I 2x2 binned on the dumbell nebula (also by accident). 

Now, the easy path for me is to just make sure it does 1x1, but I really would like to understand why de-Bayering doesn't work in the same way, or in fact at all, in 2x2. Anyone with a suggestion how to salvage the data? Or is it gone? 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.