Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - Tromat

Pages: [1] 2
General / SubframeSelector and light pollution gradient
« on: 2018 April 23 08:36:50 »
Hi folks,

I'm facing a philosophy problem with the weighting of my subframes with the said script (or process now). I'm using a full frame DSLR + 200 f/5 newtonian from my backyard in a not too polluted countryside so I have a rather wide field. When I follow the same target along the night the light gradient from the cities around my place slowy diminishes as the target reach the zenith then slowly raise as it passes the meridian.
When I'm then processing my subs, after calibration and debayer I have to weight the subs and this is where I'm facing the problem. My best frames are supposed to be right above my head and not around the horizon, but ,assuming FHWM and eccentricity doesn't change too much, the SubframeSelector will give more weight to the wrong images as it considers that light pollution is useful signal (quick answer: it's not).
I have the same issue with small clouds that will reflect light pollution and will give more weight to a poor quality subframe.

So, how do you deal with it ? I thought removing gradient using DBE or ABE but it can be complicated with lots of subs and potentially add artifacts. I was also thinking weighting only using FHWM and eccentricity but then again, a small cloud passing by will make the subs have smaller stars and then tricking the selector.

Thanks for your time :)

General / Re: Bayer Drizzle
« on: 2018 April 10 04:17:35 »
This script is not color sensor friendly  :-\
I tried it on the raw CFA files, it works, but then you lose the CFA pattern information so you have to manually specify the pattern to the debayer process. That's not a big problem but still...

General / Re: Bayer Drizzle
« on: 2018 April 09 02:48:41 »
Thanks for the feedback !

I checked the properties with the view explorer and I can find the CFA path information after Debayer process but not after using the script. I should maybe try to use the "move" output option instead of "copy".
Using the script with the raw CFA files sounds a bit weird to me but I should give it a try.

General / Re: Bayer Drizzle
« on: 2018 April 07 05:53:58 »
I had the same issue with the "missing cfa source file path" and after a few tests I found the aswer.
The problem comes from the subframe selector script, it seems to not transmit the CFA path or something.

I followed these steps:
- calibration
- debayer
- subframe selector script
- local normalization
- Image integration
- CFA Drizzle
and meet the missing path problem, but if I jump from debayer to local norm it works.

The real problem is that you can't use subframe selection and bayer drizzle :-\

No problem, and to be honest I owe this solution from Philipp Bernhard.

Glad to see it works for you :)
Quote from: msmythers
I'm not a fan of a smooth background unless the capture is just that good. Noise reduction is just that reduction not elimination and so many times we over do IMO.
What I like with the 50% grey mask is that you keep a slightly grainy texture, and not a fake plastic background.


did you tried TGV, like the example I posted today here: ?


for elegant noise reduction you can use TGVDenoise with a 50% mask.
- Create the mask with PixelMath, Formula : 0.5 apply to your image and don't forget to select "Create new image"
- Apply mask to your image
- Apply STF and take note of the low and midtone values by clicking STF Parameters (0.004455 & 0.000896 here)
- Open TGVDenoise, and use these parameters as a starting point: Strength: 1, Edge Protection: 4^-5, Smoothness: 5.
- Activate Local Support and fill shadows and midtone with previous STF values
- Iteration: raise the value from 100 to 500 or even more, the higher the better but also the longer to process

For this particular image I lowered the Edge protection to 1^-5, you have to tweak it to taste.

Image Processing Challenges / Re: Noise-reduction advice
« on: 2016 March 24 07:39:47 »
I got this information from this forum, I just can't remember where.
From here:  ;)

I would suggest trying your entire workflow without denoising to see if you can recover a good image.
The whole workflow doesn't really work actually, that's the point, the resulting picture suffers of bayer artifacts even without noise reduction.

Quote from: Pengsloth
After registering the files I split the image into RGB and then did the process over each of them and then put them back together. It worked really well I think.
The problem is that each channel is "corrupted" by the interpolation, it doesn't seems to be the most clean way to denoise. I should try with Bayerdrizzled images.


the script works very nice on CFA images but the problem is that it requires a lot of work and the result is not ok.
I'm using a DSLR and tried to split the raw files with SplitCFA so I have splitted darks, flats, biases and light, then I made all the preprocessing for each CFA list of files (4 of them so). On the stellar registration part I used the same original image so the bayer array is at the right position.
I then merged the 4 integrations to get the final color picture but there's many bayer artifacts. I tried the script on each CFA image, it works nice, but as the merging leaves many artefacts it's not usable :/

Did I make something wrong or the script cannot be used on DSLR pictures ?

Here's what it looks like on the merge image (2:1 ratio).

New Scripts and Modules / Re: New development module: TGV
« on: 2015 October 22 10:57:08 »
Yes I'm pretty confident with the deconvolution tool, the problem is there's about nothing in common with TGVRestoration.
The only similarity is the PSF section.

I don't know what noise model to use, Poisson is supposed to be useful but I can't achieve any kind of sharpening. There's no "sharpen more or less" slider or value.

New Scripts and Modules / Re: New development module: TGV
« on: 2015 October 22 07:55:08 »
The restoration tool is a nightmare to use :-\
I can't even achieve the start of the beginning of sharpening an image. I tried several noise models, did a lot of trials/errors with many different parameters tweaking and the only thing I'm success with is generating artifacts or blurring the picture.

Did someone already had successful results on sharpening linear deep sky datas ?

New Scripts and Modules / Re: New development module: TGV
« on: 2015 September 14 06:59:43 »
Hi Carlos,

and thanks for the new tools. There's a lot of work before we can use them at their best but it's promising.
TGVInpaint can also be really useful for star suppression.

Image Processing Challenges / Re: Noise reduction on M13 image
« on: 2015 September 09 00:57:29 »

just take a look at the original tutorial : it's pretty simple.
Don't forget to tick "Create new image" in the destination part of PixelMath, you don't want to replace the image but creating a new one.

Pages: [1] 2