Author Topic: Processing of planetary images  (Read 16964 times)

Offline iceman

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Processing of planetary images
« on: 2004 November 03 12:16:57 »
Hi.

Great tool! Looking forward to learning it properly! :)

Is it possible for you to give a brief (or long-winded ;)) tutorial on the best way to process planetary images such as saturn and jupiter?

The tutorials are great and it will definitely help to have additional ones.

Thanks!
Mike
My Astro Website: IceInSpace

Offline Carlos Milovic

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Re:
« Reply #1 on: 2004 November 03 15:23:48 »
Hi iceman

We'll try to make such tutorial, just give us some time. Juan is working this weeks exclusively on the standard edition, and new tutorials will depend on our free time. BTW, there are a pair of tuturials that are almost ready to publication. We need to translate them to english.

While you wait it, read the online documentation, specially the chapter about wavelets. There is a very good example with a image of the moon
Regards,

Carlos Milovic F.
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PixInsight Project Developer
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Offline Juan Conejero

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Processing of planetary images
« Reply #2 on: 2004 November 05 00:20:33 »
Hi Iceman,

I've seen you on CloudyNights forums, right? :wink: Welcome!

Please don't hesitate to send one of your images and we'll be glad to help you. You can post it here as an attachment, send it to us directly, or just put a link to the image. The images must be at their full size for us to may help.

For planetary and lunar images, the appropriate tool for enhancement and noise reduction tasks in PixInsight is the ATrousWaveletTransform process. If we can see your originals, we can propose a suitable procedure and the corresponding parameters.

Thank you.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline iceman

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Processing of planetary images
« Reply #3 on: 2004 November 08 12:49:40 »
Hi Juan and Carlos.. yes you've seen me around Cloudynights. :)

Thanks for the suggestions, when I get an image worth processing i'll take you up on that offer!

Your program looks great, and the best part is the documentation and the customer service you provide - the help to people on other forums is great and it's something that's missing from any other astro-image processing software.

Keep up the great work!

What price bracket is the STD version going to be targetted at?
Mike
My Astro Website: IceInSpace

Offline Carlos Milovic

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Re:
« Reply #4 on: 2004 November 08 14:49:07 »
Hi Mike

We don't know wich will be the final price, but our intention is to be cheaper than other softwares, or at least compite with much more tools <vbg>
I guess that for the first release it will be in the range of 100 euros (a little more than 100 dolars), but it will depend on Juan's costs and investiments. He is working exclusively on this proyect, and there are some expenses in development tools too.
Regards,

Carlos Milovic F.
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Offline iceman

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Processing of planetary images
« Reply #5 on: 2004 November 30 14:48:16 »
Hi guys.

I'd like to take you up on your offer of helping me to process a small tiny Saturn image I took this morning at f/5 with my 10" dob (no tracking) and ToUcam.

If you could see what you can do, and then let me know what values you used on which layers, that'd be great.

I've linked here the raw stacked shots, and then some wavelet processed ones using registax wavelets.

Thanks in advance.

Raw stacked version 1

Wavelet processed version 1

Raw stacked version 2

Wavelet processed version 2

Thanks again.
[/url]
Mike
My Astro Website: IceInSpace

Offline Juan Conejero

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Processing of planetary images
« Reply #6 on: 2004 December 02 02:47:28 »
Hi iceman,

I have made a couple of tests with your raw images in PixInsight.

I will show just the luminance of the images, since the originals include no relevant information in terms of color. This is mainly because the red channel is almost void. This is probably due to incorrect settings in the video capturing software for the webcam. Did you use factory default settings, or did you adjust color balance manually?

Secondly, the original images are poorly sampled for a planetary subject. This is because the image scale, measured in arcseconds per pixel, is very small to achieve an appropriate rendition of significant planetary features. In other words, you'd need absolutely perfect seeing for one or two pixels to represent a small planetary feature consistently over a significant portion of the frames in your video. So try using a higher magnification, e.g. a barlow lens, the next time.

For the reasons above, don't expect miracles!  :roll:  Having said that, these are my tests:

1. Original luminance at 100% size (your first stacked image).



2a. A test with wavelets at the original size.



2b. This is a screen copy showing parameters for the above image. The default 3x3 Linear Interpolation scaling function has been used. Care has been taken to avoid generating artifacts due to noise intensification. This is why you see noise reduction and deringing parameters.



3a. Since the original is poorly sampled, it seemed a good idea resampling it up prior wavelets processing. I resampled the image above (1) to 230% its original size using bicubic interpolation. Why 230% and not just 200%, for example? Because if we just double or halve the size, we are simply moving image structures between dimensional scales in a powers-of-two scheme (2,4,8,16...). In general, this does not increase our chances for a better separation of the image into different scale levels.



3b. This is my try with wavelets. The 3x3 Small Scale scaling function was used. Note how this time the first three wavelet layers can be discarded; they contain just noise. The scaling function used is better to split the images into many small-scale wavelet layers. This was necessary this time because noise was present at many different layers, so a better separation helped reducing it, while sharpening the image at the same time.



3c. Finally, these are the parameters used. Don't forget that the scaling function is 3x3 Small Scale.



Of course, one can go further than the above results, if desired. I've tried to extract what I think is there, without introducing artifacts due to the noise. Of course the parameters shown are by no means the only possible ones, neither the best ones.

Hope this helps.
Juan Conejero
PixInsight Development Team
http://pixinsight.com/

Offline iceman

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Processing of planetary images
« Reply #7 on: 2004 December 05 15:24:14 »
Juan,

Thankyou very much for your time and efforts in processing my initial attempt at Saturn. I know I gave you very little to work with in terms of a raw image. I appreciate what you did.

I've been able to capture at f/10 this morning and have some better raw images. I'll try and follow your steps, but for now i've just used registax and photoshop.

First lot is the raw stacked images, stacked about 300 of 750. If you're able to process them better than me, I'd be most grateful.




Second lot is after my wavelet processing attempts, with some minor adjustments in photoshop as well.



So, how 'bout that Cassini Division!?

Can anyone enlighten me as to the possible causes?
1. Focus not sharp?
2. Collimation off?
3. Seeing bad?
4. Not restrictive enough when aligning/stacking in registax?
5. All of the above?
6. None of the above?

Appreciate any help or suggestions.. this image is already 5 times better than any previous Saturn image i've taken so although I'm in pain and frustration, i'm still pleased that it's finally recognisable as Saturn! :)

Thanks very much for your help and advice.
Mike
My Astro Website: IceInSpace

Offline Juan Conejero

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Processing of planetary images
« Reply #8 on: 2004 December 06 08:04:57 »
Hi Mike,

Here is my try:



Wavelet parameters are: Use luminance, Linear scaling, Layer 2 bias = +1.5, Layer 2 Noise reduction = {amount=0.6, n=2, k=5}, High Range = 0.1. The rest by default.

Regarding why your image doesn't show the Cassini division, I think it may be due to poor tracking. The planet disk seems elongated. This may be added to other problems that you mentioned (focus, etc.).

Processing software is not one of your main problems IMHO; however, I've noticed excessive clipping at the shadows of the histograms in your processed images. Always be *very* careful not to clip histograms. In the case of planetary images, as for deep-sky, don't try to get a perfect black sky background since this always means a lack of data and artificial-looking planetary edges.

Good luck and good seeing!
Juan Conejero
PixInsight Development Team
http://pixinsight.com/