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Vignetting, discussion about methods of resolution
Tman
post Aug 24 2005, 07:37 AM
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Hi Nirgal and all, I would like to discuss about vignetting and methods of resolution for it. I'm mainly interested in mathematical methods that could automatically calculate and adjust the right grey value for each pixel in a single picture.

My current method works with more or less transparent layers over the original picture that so roughly are able to balance the grey values. A perfect layer have to be the exact inverted brightness difference of each picture with this shadow effects. This method is very effective if you get the correct inverted values. These shots of the Mars sky come nearly at such a perfect mask, but not always. And of course the center of the pictures lose much of theirs original brightness/luminance sadly.

I have in mind a mathematical method that can adjust each grey value in a pic in order to obtain a completely balanced brightness over the entire picture. But I'm not in the position to reach that. I only know one have to start with the calculation of the grey values in the center of the picture. In the center are quasi the reference values of the whole picture, if I'm correct.
Is there a possibility (mathematical method) to get (roughly) the same brightness and luminance like in the center over the whole picture from the MERs?

Greetings, Peter


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Tman
post Aug 25 2005, 02:17 PM
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Hi Michael, best we would talk about it in German, only the other members here would pull one's hair out (or so rolleyes.gif ).

I dont know the FFT method so far, but it seems to be fundamental when programming high quality picture editing software. After a quick search in the web I found very interesting examples - but a.t.m. definitively too difficult to me.

Did you wrote a program for the FFT caculation that now works automatically when processing the MER pics?
My only hope is that you could programming a plug-in to PhotoShop with it cool.gif biggrin.gif
When you get satisfactory results then, I would be the first customer!


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MichaelT
post Aug 25 2005, 04:39 PM
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QUOTE (Tman @ Aug 25 2005, 02:17 PM)
Hi Michael, best we would talk about it in German, only the other members here would pull one's hair out (or so rolleyes.gif ).

Probably / Vielleicht biggrin.gif

I think that my program works quite well now, though, you have to treat every image individually - not fully automatic, yet. Well, you only have to tune one parameter.

Here are some examples:
Sol 107, before and after anti-vignetting:


Sol 581 partial panorama (Autostitch):


Looks quite promising.

QUOTE
Did you wrote a program for the FFT caculation that now works automatically when processing the MER pics?
My only hope is that you could programming a plug-in to PhotoShop with it  cool.gif biggrin.gif
When you get satisfactory results then, I would be the first customer!
*

Unfortunately, I use a data language called IDL, which is a commercial product and fairly expensive sad.gif That's what we use at our institute. I wish I'd be able to write a Photoshop plug-in, but I am not mad.gif If anybody else here would like to transfer this into another language, I could provide commented code.

Michael

ps: Ich schicke Dir gleich noch eine persönliche Nachricht auf Deinen Account.
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Nirgal
post Aug 25 2005, 05:16 PM
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QUOTE (MichaelT @ Aug 25 2005, 06:39 PM)
Probably / Vielleicht  biggrin.gif

Looks quite promising.
Unfortunately, I use a data language called IDL, which is a commercial product and fairly expensive sad.gif That's what we use at our institute. I wish I'd be able to write a Photoshop plug-in, but I am not mad.gif If anybody else here would like to transfer this into another language, I could provide commented code.

Michael

ps: Ich schicke Dir gleich noch eine persönliche Nachricht auf Deinen Account.
*



Hi Micheal,

your approach sounds interesting: surely more involved than the ad-hoc method
I implemented in my "unstrip" program (I've just started to research vignetting problems and was very surprised that such a comparatively simple method
(even without FFT) could remove the "stripes" in multi-frame mosaics.





not perfect, but could be used for "cleaning" up existing panoramas without re-stitching ...

However, I'm interested in implementing your FFT-based method in the C language
(provided that it fits within my existing image processing libraries (FFT, etc)
so I could possibly provide a windows stand-alone program that anyone could use
as a simple command line utility...

wink.gif
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Posts in this topic
- Tman   Vignetting   Aug 24 2005, 07:37 AM
- - Nirgal   Hi Tman, mathematically, we can describe vignetti...   Aug 24 2005, 11:29 PM
- - Tman   Hi Nirgal, probably you're right and it's ...   Aug 25 2005, 11:26 AM
|- - Nirgal   Thanks Micheal, hopefully I will find the time to...   Aug 25 2005, 08:46 PM
|- - Tman   QUOTE (Nirgal @ Aug 25 2005, 10:46 PM)...no n...   Aug 25 2005, 09:29 PM
|- - Tesheiner   QUOTE (Tman @ Aug 25 2005, 11:29 PM)Guess I...   Aug 26 2005, 06:42 AM
- - MichaelT   Hi Tman, I tried it using "Fast Fourier Tran...   Aug 25 2005, 12:42 PM
- - Tman   Hi Michael, best we would talk about it in German,...   Aug 25 2005, 02:17 PM
|- - MichaelT   QUOTE (Tman @ Aug 25 2005, 02:17 PM)Hi Michae...   Aug 25 2005, 04:39 PM
|- - Nirgal   QUOTE (MichaelT @ Aug 25 2005, 06:39 PM)Proba...   Aug 25 2005, 05:16 PM
|- - MichaelT   QUOTE (Nirgal @ Aug 25 2005, 05:16 PM)Hi Mich...   Aug 25 2005, 05:59 PM
- - Tman   Yeah sounds really good so far That would be fant...   Aug 25 2005, 08:38 PM
- - MichaelT   Nirgal, I finished the commenting of my program to...   Aug 26 2005, 05:57 PM
- - MichaelT   I have now modified the anti-vignetting-program (u...   Sep 14 2005, 05:49 PM
|- - dilo   WOW! MichaelT, I think would be really GREAT t...   Sep 14 2005, 06:38 PM
||- - mhoward   QUOTE (dilo @ Sep 14 2005, 06:38 PM)WOW! ...   Nov 11 2005, 04:09 PM
||- - dilo   QUOTE (mhoward @ Nov 11 2005, 04:09 PM)If the...   Nov 13 2005, 08:02 AM
|- - Bob Shaw   MichaelT: Do you think your anti-vignetting app c...   Sep 14 2005, 06:53 PM
|- - MichaelT   QUOTE (Bob Shaw @ Sep 14 2005, 06:53 PM)Micha...   Sep 14 2005, 07:39 PM
|- - Bob Shaw   QUOTE (MichaelT @ Sep 14 2005, 08:39 PM)Bob, ...   Sep 14 2005, 08:43 PM
- - djellison   I'm guessing there's no flatfield or darkf...   Sep 14 2005, 07:03 PM
|- - tedstryk   I usually try to make a blank image with my digita...   Sep 14 2005, 07:32 PM
- - MichaelT   Hi, I put an updated version of the anti-vignetti...   Oct 24 2005, 04:30 PM
|- - Tesheiner   QUOTE (MichaelT @ Oct 24 2005, 06:30 PM)Anywa...   Nov 1 2005, 02:25 PM
- - jvandriel   Tman, what I mean to say with those lines is the ...   Nov 1 2005, 10:31 AM
- - Tman   You're right Jvandriel, it's for both very...   Nov 1 2005, 11:59 AM
- - djellison   I dont mind it running in IDL, but I would really ...   Nov 1 2005, 04:00 PM
- - MichaelT   QUOTE (djellison @ Nov 1 2005, 04:00 PM)I don...   Nov 1 2005, 04:22 PM
- - MichaelT   I just put online Version 2.0, now with batch proc...   Nov 1 2005, 05:45 PM
- - Tman   Hi Michael, Tried the batch processing just with ...   Nov 1 2005, 06:58 PM
- - jvandriel   Michael T, today I used for the first time your a...   Nov 3 2005, 03:20 PM
- - Nix   I'm starting to use your tool too, looks prett...   Nov 3 2005, 07:12 PM
- - MichaelT   Hi Michael, it would indeed be very nice if someo...   Nov 13 2005, 06:17 PM
|- - jaredGalen   I would be interested in giving it a go. I made a ...   Nov 13 2005, 06:49 PM
|- - MichaelT   QUOTE (jaredGalen @ Nov 13 2005, 06:49 PM)I w...   Nov 14 2005, 06:12 PM
|- - jaredGalen   Wow, okay. Looks like I have my work cut out for ...   Nov 14 2005, 06:33 PM
- - slinted   Michael, thank you for sharing the code to this ap...   Nov 14 2005, 11:15 PM
|- - jaredGalen   QUOTE (slinted @ Nov 15 2005, 12:15 AM)Jared,...   Nov 15 2005, 09:05 AM
- - jamescanvin   How long does this program take to run for you guy...   Nov 15 2005, 02:50 AM
|- - MichaelT   QUOTE (jamescanvin @ Nov 15 2005, 02:50 AM)Ho...   Nov 15 2005, 10:04 AM
- - Tman   The same to me - 5 seconds. My PC system runs 2,4...   Nov 15 2005, 10:51 AM
- - jamescanvin   Hmm, 5 seconds eh, that's a bit quicker than 5...   Nov 15 2005, 01:34 PM
- - Nix   no mac, but 3 seconds, although it might well be a...   Nov 15 2005, 05:28 PM
|- - jamescanvin   QUOTE (NIX @ Nov 16 2005, 04:28 AM)Hope you f...   Nov 15 2005, 11:13 PM
- - MichaelT   I made a minor modification to the program. I don...   Nov 16 2005, 08:47 AM
|- - jaredGalen   Hi, I haven't a much of a chance to do any cod...   Nov 16 2005, 01:38 PM
||- - MichaelT   QUOTE (jaredGalen @ Nov 16 2005, 01:38 PM)Hi,...   Nov 16 2005, 03:12 PM
||- - Nirgal   Micheal, I just like to say thank you for sharing...   Nov 16 2005, 08:36 PM
||- - MichaelT   QUOTE (Nirgal @ Nov 16 2005, 08:36 PM)Micheal...   Nov 17 2005, 08:45 PM
|- - jamescanvin   QUOTE (MichaelT @ Nov 16 2005, 07:47 PM)I mad...   Nov 17 2005, 03:10 AM
|- - jamescanvin   QUOTE (MichaelT @ Nov 16 2005, 07:47 PM)I mad...   Nov 19 2005, 02:43 AM
|- - MichaelT   QUOTE (jamescanvin @ Nov 19 2005, 02:43 AM)It...   Nov 19 2005, 08:05 AM
- - jvandriel   MichaelT, I just downloaded Anti_Vig 2.0.1, but w...   Nov 18 2005, 12:41 PM
|- - MichaelT   QUOTE (jvandriel @ Nov 18 2005, 12:41 PM)Mich...   Nov 18 2005, 01:49 PM
- - Tman   Hi Jvandriel, I guess you renamed it as "Ant...   Nov 18 2005, 01:44 PM
|- - MichaelT   QUOTE (Tman @ Nov 18 2005, 01:44 PM)Hi Jvandr...   Nov 18 2005, 01:54 PM
- - MichaelT   Would you like me to include the version number in...   Nov 18 2005, 02:04 PM
- - Tman   Hi Michael, just reply overlap. Regarding version...   Nov 18 2005, 02:09 PM
- - jvandriel   MichaelT and Tman, thanks for the advice. I did i...   Nov 19 2005, 02:04 PM
|- - MichaelT   QUOTE (jvandriel @ Nov 19 2005, 02:04 PM)is i...   Nov 24 2005, 05:40 PM
- - MichaelT   After a long, long time I am currently developing ...   May 5 2006, 11:46 AM
|- - hortonheardawho   Hi Michael, I have been interested in your anti-v...   Jun 9 2006, 10:16 PM
- - hortonheardawho   Doesn't look like Michael is monitoring this t...   Jun 11 2006, 07:58 PM
|- - MichaelT   QUOTE (hortonheardawho @ Jun 11 2006, 07...   Jun 12 2006, 05:12 PM
- - DonPMitchell   Very cool work, Michael. I know in a mathematical...   Jun 12 2006, 06:07 PM
|- - Airbag   QUOTE (DonPMitchell @ Jun 12 2006, 02:07 ...   Jun 13 2006, 02:47 AM
||- - helvick   QUOTE (Airbag @ Jun 13 2006, 03:47 AM) Th...   Jun 13 2006, 12:53 PM
|- - MichaelT   QUOTE (DonPMitchell @ Jun 12 2006, 06:07 ...   Jun 14 2006, 05:06 PM
|- - DonPMitchell   If they measured the camera response, then that is...   Jun 14 2006, 05:42 PM
- - jrdahlman   Is this anti-vignetting program specifically for M...   Jun 29 2006, 07:43 PM
|- - MichaelT   QUOTE (jrdahlman @ Jun 29 2006, 07:43 PM)...   Jul 3 2006, 06:03 PM
- - edstrick   The Voyager (mariners, viking) cameras have other ...   Jul 4 2006, 09:51 AM
- - jrdahlman   Sorry for the delay. My website requires me to upl...   Jul 5 2006, 04:47 PM
|- - MichaelT   QUOTE (jrdahlman @ Jul 5 2006, 04:47 PM) ...   Jul 6 2006, 12:37 PM
|- - ugordan   QUOTE (jrdahlman @ Jul 5 2006, 05:47 PM) ...   Jul 6 2006, 01:01 PM
|- - MichaelT   QUOTE (jrdahlman @ Jul 5 2006, 04:47 PM) ...   Jul 6 2006, 05:59 PM
- - um3k   Another problem is that Voyager images exhibit a l...   Jul 6 2006, 01:49 PM
- - um3k   jrdahlman, these websites may come in handy for yo...   Jul 6 2006, 08:06 PM
- - jrdahlman   Oh, I know that you can download all the images. I...   Jul 6 2006, 08:59 PM
|- - um3k   QUOTE (jrdahlman @ Jul 6 2006, 04:59 PM) ...   Jul 7 2006, 12:57 AM
- - edstrick   Playing with Voyager 1 wide angle images, I found ...   Jul 7 2006, 11:37 AM
- - jrdahlman   I would like to point out that the program um3k...   Jul 10 2006, 06:19 AM
- - edstrick   Dark current images are those taken with zero expo...   Jul 10 2006, 09:42 AM


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