Vignetting, discussion about methods of resolution Options

[Bob Shaw]

MichaelT:

Do you think your anti-vignetting app could be tweaked to sort out the tone variations seen across the Surveyor frames?

Bob Shaw

[djellison]

I'm guessing there's no flatfield or darkfield for the Surveyor stuff ( where can you get it all anyway?)
If you took all the surveyor frames that didnt include the 'sky' and averaged them, you might get an appropriate 'flat field' - which you could then invert, and overlay at a few percent opacity on all the other frames.

Doug

[tedstryk]

I usually try to make a blank image with my digital camera to record only the vignetting so that it can be subtracted. Here are some pans where it works well. Sometimes it works, sometimes it doesn't. To do this automatically would be great!

[MichaelT]

MichaelT:

Do you think your anti-vignetting app could be tweaked to sort out the tone variations seen across the Surveyor frames?

Bob Shaw

Bob, have you got one for me to try it out? At the moment I don't quite know what those images look like. These tone variation would have to be roughly rotation-symmetric to eliminate them. I could also change it that way that it uses some polynomial fitting functions. Then it might work with non-rotation-symmetric variations, too.

Michael

[Bob Shaw]

Bob, have you got one for me to try it out? At the moment I don't quite know what those images look like. These tone variation would have to be roughly rotation-symmetric to eliminate them. I could also change it that way that it uses some polynomial fitting functions. Then it might work with non-rotation-symmetric variations, too.

Michael

MichaelT:

I can scan a couple, and will post them here, and will also have a look at some WWW locations. Nothing will be particularly clever in terms of quality (ask Phil Stooke, he's got a lot of more-or-less first generation-ish scans which he's used for some of his Surveyor panoramas).

Oh, and on further thought, what about automating Lunar Orbiter image drop-offs, or Mariner 6/7 ghost images, or...

...look what you started!

Bob Shaw

[MichaelT]

Hi,

I put an updated version of the anti-vignetting program online. I corrected some minor errors and it now supports output as 16-bit-TIFF. That way one can do all the adjusting after the anti-vignetting process wihtout loosing any information. As usual it is a precompiled IDL-program and can be used with RSI's Virtual Machine (see earlier posts).
You can find the program here: http://www.muk.uni-hannover.de/~theusner/mars/anti_vig.sav

Tman pointed me to the fact that some people are already using that program, and the results really look nice. As I was in the final stages of PhD-thesis-writing until mid-October, I had not noticed that so far But now I am done

Anyway, I would not mind input from the users. Is there something that you would like to be improved?

Bob: Did you scan any images so far?

Michael

[jvandriel]

Tman,
what I mean to say with those lines is the following:

Anti-vignetting of Navcam images gives around 20% better images and Pancam images
around 3 or 4% better images. ( see the percentage after vignetting. )
The end result of every image after anti-vignetting with MichaelT's program is much better, as you describe.
Therefore I use the anti-vignetting program for Navcam and Pancam images for every
panoramic view I make.

jvandriel

[Tman]

You're right Jvandriel, it's for both very helpful. If one use them without automatical brightness/color correction during the stitching process, especial with PTGui's "PhotoShop with feathur" version, one mostly have only to correct a brightness gradient that caused by the sun direction during the shot (among the correction of exposure). I overcome this rest gradient with an adjusted mask over each frame.

"those lines" adress my post here, right: http://www.unmannedspaceflight.com/index.p...indpost&p=25066

[Tesheiner]

Anyway, I would not mind input from the users. Is there something that you would like to be improved?

Michael, consider this as a letter to Santa Claus...

"I want a standalone version without IDL dependency".

[djellison]

I dont mind it running in IDL, but I would really like a batch processing tool.

Doug

[MichaelT]

I dont mind it running in IDL, but I would really like a batch processing tool.

Doug

Ok, that is something that I had in mind, too. I will implement a button to do batch processing soon.

Michael, consider this as a letter to Santa Claus... 

"I want a standalone version without IDL dependency".

Unfortunately, I do not have the ability to convert the program into a stand-alone version. The necessary IDL packages are quite expensive and the uni institute that I am working at did not buy them for that reason
If there is anybody who could help me with that problem, please tell me.

Michael

[MichaelT]

I just put online Version 2.0, now with batch processing option ('batch' button). You can do the vignetting settings before choosing the batch option (eg. with a template image). The settings will then be applied to all the selected images. You can also select vertical parts of the image (eg. the sky, see 'Help') that will be used to determine the amount of vignetting. That selection will the be used for all batch images.

So far, the images will be generated in the folder where the files are located. That will be changed in a future version. An 'av' is added to the files to prevent overwriting of the original images.

http://www.muk.uni-hannover.de/~theusner/mars/anti_vig.sav

Let me know if there are any problems.

Michael

[Tman]

Hi Michael,

Tried the batch processing just with the last Spirit's sol 649 Pancam files which I used for a pan and it works very well so far.

Thanks!

Very helpful to last the fastest MER-pans producer forum of the world.

[jvandriel]

Michael T,

today I used for the first time your anti-vignetting program with the batch processing addition. ( V 2.0 )

It works great. No problems at all.

jvandriel

[Nix]

I'm starting to use your tool too, looks pretty good !

Thanks

Nico