Author Topic: Multiple DBE passes-problem(probably dumb)  (Read 5789 times)

Offline dhalliday

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Multiple DBE passes-problem(probably dumb)
« on: 2010 February 10 14:52:20 »
Gang
Fearing that my "DBE tuneup" thread is not getting looked at,I have a question or two ( >:D) more..
Is it reasonable to apply ABE as a "starter" on an image,and then zone in with DBE...?
It allows me to not have to adjust the parameters so much...but is ABE "harming" my original data..?
Or just not doing as goos a job as DBE...?

When I have applied DBE...and have a new image ("bghy_DBE")...why do I not seem able to go ahead and click on IT..and do another round of DBE??
I seem to have to CLOSE DBE and then RESTART it,before it will allow me to delete the original image,or start work on a the new (post DBE) image...
I must be missing something...it seems awkward..!

Dave
Dave Halliday
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Offline dhalliday

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #1 on: 2010 February 11 03:50:23 »
OK...I think I am maybe asking too many questions around here...!!
The DBE one is trivial,really.
Back to RGB combine...
I keep doing some Wavelet NR (thanks Jack !!) and DBE to each of the RGB files BEFORE combining them...
Are folks ABSOLUTELY sure this is not neccessary/a waste of time..?
Here is some better (420 sec) M1 data,by the way;
http://www.flickr.com/photos/daveh56/4347805905/sizes/o/
I intend to get more frames tonite (10 so far LRGB)

AND,here is what I have been doing BEFORE combining the RGB...in this case this is work on B channel;
http://www.flickr.com/photos/daveh56/4346936769/sizes/l/

And just out of interest,here is how my deconvolyion of M57 is coming along;
http://www.flickr.com/photos/daveh56/4347846125/sizes/o/

A bit more reassurance that RGB combine should be "kept simple",and the trick to speed up DBE would be appreciated...!!

Dave
Dave Halliday
8" Newtonian/Vixen VC200L/ TV 101,etc etc
SSAG/EQ6
CGE Pro
SBIG ST2K,ST10XME

Offline Niall Saunders

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #2 on: 2010 February 11 05:58:14 »
Quote
I keep doing some Wavelet NR (thanks Jack !!) and DBE to each of the RGB files BEFORE combining them...
Are folks ABSOLUTELY sure this is not neccessary/a waste of time..?

It really is NOT necessary to mess around with the individual channels prior to the initial combine. I 'used to' to this, but realised that the new processes 'work better' on the full-colour data.

DBE is a classic example - there is just NO NEED to define three separate sets of sample points for each of the channels. Just define ONE set of sample points, click the button, and watch the magic (you probably won't even have time for a 'sip' of coffee, far less a 'cup'):D

I can't fully comment about WaveletNR - as I don't use it. I prefer to work in the realm of ACDNR - and that works in TWO domains, Chrominance and Luminance. Which makes things simple again. If you already have your three-channel image, then ACDNR can work on the 'colour-side' of the data as one step, and the 'luminance-side' of the data as a second step - and the most that you will have to do is click a couple of selction boxes to change between the two.

And, I have found that it IS better to handle the ACDNR process as two discrete steps - simply because you are dealing with two totally different, and unique, 'noise sources' ('chrominance' and 'luminance') - and they really do benefit from different approaches in my experience.

But - admit it - it IS getting 'easier', isn't it  ???

Cheers,
Cheers,
Niall Saunders
Clinterty Observatories
Aberdeen, UK

Altair Astro GSO 10" f/8 Ritchey Chrétien CF OTA on EQ8 mount with homebrew 3D Balance and Pier
Moonfish ED80 APO & Celestron Omni XLT 120
QHY10 CCD & QHY5L-II Colour
9mm TS-OAG and Meade DSI-IIC

Offline mmirot

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #3 on: 2010 February 11 11:11:14 »
 I do DBE on separate channels myself.
It can be helpful background is quiet different in the channels.
For examples many narrowband images have quite different distribution compared to a galaxy.

Max

Offline Harry page

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #4 on: 2010 February 11 12:28:08 »
Hi

I am with niall on this can not see the point on doing it on seperate channels , to hard for a simple like me  :o


Harry
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Offline dhalliday

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #5 on: 2010 February 11 16:47:17 »
How about my original issue...
Is there a way to just keep reapplying DBE to the result of the last pass..? (with new parameters..?)
I seem to have to close it down BEFORE I can make the next (new result) become "active"...
This seems so clumsy I am sure I am doing something wrong >:D

Niall..YES...a bit easier...

Dave
Dave Halliday
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Offline Niall Saunders

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #6 on: 2010 February 12 06:02:44 »
Hi Dave,

What about dropping the 'apply process' icon (the little blue triangle) on the workspace background. Then close DBE. Then double-click the process icon that you dropped on the workspace, then select the image that you want to work on (all of these suggestions 'from memory' as I am not at my PI computer at the moment)

Does that help?

Cheers,
Cheers,
Niall Saunders
Clinterty Observatories
Aberdeen, UK

Altair Astro GSO 10" f/8 Ritchey Chrétien CF OTA on EQ8 mount with homebrew 3D Balance and Pier
Moonfish ED80 APO & Celestron Omni XLT 120
QHY10 CCD & QHY5L-II Colour
9mm TS-OAG and Meade DSI-IIC

Offline mmirot

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #7 on: 2010 February 12 08:02:26 »
Btw I rarely run a DBE multiple passes.
Rather I adjust the points at run again on the same source image. This works very well for me.

One artifact I get with DBE is a dark area at the transition edge from the background to brighter the nebula.
I find that placing a some sampling points at the very start of the nebulosity help eliminate a dark ring at the transition.



Does anyone see this too?

How do you deal with it?

perhaps I should adjust other parameters?

Max


Offline dhalliday

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #8 on: 2010 February 12 12:03:43 »
Max
What sort of density of points are you running?
Maybe LESS is better to avoid the blotching...
What about "smoothing"...
Any ideas on that ..??

I often find the DBE results has "blotches" as well as the "ring defect" you described..
My feeling is that rather than "start over" on the original,I want to apply a "fine tuning"..a second coat of paint as it were..
Now, I realize I am seeing this stuff in the HIGHLY stretched SCT image,...but maybe I am a perfectionist..?
Niall; I will try your suggestion...but so far I CANNOT "get rid of" the image with all the points on it,nor apply a new set of points to the first result,without shutting off DBE,and restarting it...
This was one of my original issues..
Good discussion going here..! >:D

Dave
Dave Halliday
8" Newtonian/Vixen VC200L/ TV 101,etc etc
SSAG/EQ6
CGE Pro
SBIG ST2K,ST10XME

Offline dhalliday

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Re: Multiple DBE passes-problem(probably dumb)
« Reply #9 on: 2010 February 13 08:45:58 »
Niall
I tried that "process Icon" thingy...as you suggested
Works real good... >:D
I guess their are a lot of "fiddly bits" in Pix I have not learned yet...!!!
And I suspect our tolerance for "half assed study" of the process is a wee bit different .. O:)
In fact I used it on the RG and B frames of M51...all one after another,very quick !!
Sadly I only had 3 frames in blue,so it is a bit noisy,but here it is...
It is unbinned,480 seconds RGB,20 cm f/5 Newtonian.

http://www.flickr.com/photos/daveh56/4353252199/

If anyone needs data..(!) let me know...
Clouds now the story for 4 days...

Dave
Dave Halliday
8" Newtonian/Vixen VC200L/ TV 101,etc etc
SSAG/EQ6
CGE Pro
SBIG ST2K,ST10XME