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Messages - ChoJin

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PCL and PJSR Development / Re: parallel processing
« on: 2018 February 27 09:58:09 »
thank you very much for the pointers! :-)

Bug Reports / Re: Fedora 27 and PixInsight work around
« on: 2018 February 27 06:23:23 »
Thanks, I'll take a look.

Indeed, I was very surprised considering I was running a standard ubuntu 17.10, and I couldn't believe either I was the first one to try that ;-)

The only non-standard thing I can think of, is that I was encrypting my home directory (with ecryptfs). Otherwise it was a standard install.

I'll take a look at the code, and see if I see anything wrong. Otherwise, I'll try to debug this issue once I get a chance.

Thanks Juan.
PS: I had a "parallel code" PCL-related question in the PCL sub-forum, just in case you didn't see it, and you're probably one of the few who can answer me ;-)

Bug Reports / Re: Fedora 27 and PixInsight work around
« on: 2018 February 27 05:58:25 »
btw, is it possible to have the source code of the linux installer?

I tried to run it on ubuntu 17.10 (standard fresh new default install) and it completely messed up the X install (to say the least, really weird on, blue background, not showing any icons anymore, couldn't log in)

Fortunately I had installed sshd before, so I could repair the system. I tried to force-reinstall a couple of X/gnome related package to narrow down the problem, but none of the obvious package reinstall fixed it. I therefore used a script to force-reinstall the whole system (the package already installed) and that fixed it.

Sorry, I can't really therefore know what was wrong with the installer, and I didn't have the patience to rerun it with a strace to spy on it, but something was messing up the ubuntu 17.10 somewhere.
If I could get access to the installer's source code, maybe I could take a look to see if I can see how this happened?

yes, avgDev, you either just copy the value to the box where you can see the full value (the one on the full left), or you copy it as float and exponent. I prefer to just copy it as is to the left box (and the two other boxes will update automatically)

With my very very limited experience:
- using TGV on linear gives me weird blotches, even after tuning the values for hours. I'm probably doing it wrong. I therefore used MLT following the M81&M82 tutorial from, and got much better results.

- on non linear, I got quite nice results with ACDNR (using lightness mask enabled on both lum and chroma), I could match the results with TGV, but it wasn't really better (at least to my opinion on the data I tried on) to justify how slower it was. So even after hours of TGV Tuning, I went back to ACDNR with my default values.
Also note that I had run MLT during the linear process, hence I probably get better results on non-linear because of that.

For a good edge protection value you might start with the following:

- create a preview over a background area without stars or other stuff
- run the statistics process
- in the parameters of the statistics process add the standard deviation.
- make sure the values are displayed normalized
- use the stddev value for your edge protection value

General / Re: How/when to combine synthetic lum
« on: 2018 February 25 02:26:05 »
thank you Rob

General / Re: Dark frames and DSLR's
« on: 2018 February 24 16:03:08 »
could you elaborate on your DIY cooling system for the dslr? (even going into the details of electronic design if you designed it yourself)

Gallery / Re: M42 - LRGB
« on: 2018 February 24 11:08:00 »
for the deconvolution, I thought it could bring more details to the nebulosity. I usually don't mind that much about bloated stars unlike most ppl on this forum ;-)

for the collimation, i'm just curious about why the blooms on medium-sized stars seem to be mostly oriented upward instead of being circular.

General / Re: How/when to combine synthetic lum
« on: 2018 February 24 04:32:30 »

Thanks Rob,

I tried to follow the RGBWorkingSpace+ChannelCombination tutorial from Juan, but I get the following error message when applying the RGBWorkingSpace process:

'Instance validation failed'

Playing with the parameters it seems to come from the values put for the chromaticity coordinates.
Any clue?

In the meantime I guess I have no other solution than doing the stretch+linearfit method then ;-)

Couple of questions though:

- Is there any need (even slightly theorical) for running PCC after LRGBCombination, or am I guaranteed to end up with the exact same correct color calibration after my LRGBCombination (assuming I used linearfit)?

- are there any benefit of using the saturation boost from LRGBCombination instead of doing it afterward using the CurveTransform/ColorSaturation processes (which have the benefit of being able to control the effect with a mask)?

Gallery / Re: M42 - LRGB
« on: 2018 February 24 04:20:01 »

congrats Michael. This target really is a wonder.

I don't have any experience with this target, but did you try/apply deconvolution (after integration and DBE, while still linear)?

NB: it seems to me that your mirrors might benefit from some collimation?

PCL and PJSR Development / parallel processing
« on: 2018 February 23 11:35:45 »

I'd like to implement a new process module, and for that I'd like to know which process module would be the best example regarding parallel processing and how it should be best done (best practice/coding-wise within the PCL framework).

NB: I know how to do parallel algorithms, my question is specific to how to do it within PCL for a process module.

General / How/when to combine synthetic lum
« on: 2018 February 23 11:24:33 »

I'm trying to figure out the best way to combine a synthetic lum.

My synthetic lum is computed using ImageIntegration (noise weighting) from my RGB data (DSLR) after DBE+PhotometricColorCalibration+BackgroundNeutralization+SCNR.

I did some processing on this synthetic lum (deconvolution+noise reduction) and now I'm trying to figure out how/when to merge back, with my RGB data, this processed synthetic lum without messing up my color calibration.

I stumbled upon

and I'm not sure which method is the best/less hazardous. Should I stretch both my Lsyn and RGB, Linearfit my Lsyn and LRGBCombine them, or should I go with the linear CIE XYZ space method?
Which one is best (for SNR, color balance etc.)? What are the advantages and drawbacks of both methods?

Hopefully someone can help shed some insights on this matter, because I'm having a hard time deciding :o

very nice documentation with the included tutorial.  ^-^

Likewise, you can put pdf on github (in a doc subdirectory for instance), and github is nice enough to even render pdf while browsing it.

General / Re: Additive Stacking?
« on: 2018 February 21 02:43:20 »
the 30sec has a worse SNR than the 3x30sec. What Rick is comparing is 3x30sec additive stacking vs 3x30sec averaging stacking, which is the same by just a factor (1/3 in this case): (I1+I2+I3) vs (1/3)*(I1+I2+I3).

In other words, there is no benefit for SNR to do "additive stacking" instead of "averaging stacking".

Bug Reports / Re: Cannot save project
« on: 2018 February 18 05:54:17 »
AFAIK, you lose images' history as well

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