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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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MichaelT
post Sep 14 2005, 05:49 PM
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I have now modified the anti-vignetting-program (using IDL) such that it can deal with any kind of jpeg-image. Also, it does not use FFT any longer but simply takes a 2D-cosine-shaped mask. That mask is fitted to the chosen image and the amount of vignetting automatically determined (that can be done RGB-channel specific). It also allows to save images as 16-bit-tiff so that none of the original information is lost in the out-put image. You can also do manual adjustments if the amount of vignetting is over- or underestimated by the program (depends on the structure of the image). All that has to be done with each single image and cannot be aplied to a ready panorama.

Below are two examples (SOL 582).

Without anit-vignetting:


After anti-vignetting:


After anti-vignetting the sky shows a very even color distribution, without these nasty green edges. These are obviously due to different amounts of vignetting in the RGB-channels.

I also tested that program with scanned slides and digital camera images and it works very well. So it does not only work with martian craters but also with terrestrial ones biggrin.gif The image below shows Wolfe Creek meteorite crater in Western Australia. Its got a diameter of 850 m and is about 30-40 meters deep. Like martian craters it is filled with sand and dust (80 meters).

Panorama from three frames.


The only draw-back is that I cannot provide a stand-alone version of that program unsure.gif Though, a pre-compiled version of the program can be run with RSI's "Virtual Machine". It's free, but requires registering and is a 115 MB download mad.gif
Is there anybody here who's got a license to turn this IDL-program into a stand-alone one?

Michael
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dilo
post Sep 14 2005, 06:38 PM
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WOW!
MichaelT, I think would be really GREAT to implement your algorithm inside MMB... I would know opinion from the other Michael on this item... rolleyes.gif


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mhoward
post Nov 11 2005, 04:09 PM
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QUOTE (dilo @ Sep 14 2005, 06:38 PM)
WOW!
MichaelT, I think would be really GREAT to implement your algorithm inside MMB... I would know opinion from the other Michael on this item...  rolleyes.gif
*


If there were a Java version of this algorithm, it might be possible to put it into MMB. It would be neat to have Navcam mmbpans with anti-vignetted images. Since MMB is open-source now somebody else could work on this as well.
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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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