Verdandi: the new blender

[Harry van der Wolf]

Hi,

I did some preliminary tests with verdandi(1), the new blender. In general it works fine, but in 2 panos I got "washed out" colors, maybe due to CIECAM colors in the originals (That comes to mind now that I type this mail. I will check tonight).

It is much faster then enblend, just like multiblend is/was.

Some french website also paid attention to it: http://www.panophoto.org/forums/viewtopic.php?f=67&t=15190

Are there any other users already with test results?

Harry

(1): verdandi: http://wiki.panotools.org/index.php?title=Verdandi

[Gnome Nomad]

Haven't tried 2015 yet, but can it be set to use enblend instead of verdandi? I read the wiki & decided I prefer enblend's soft seam.

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[Harry van der Wolf]

Hi,

It is the other way round. Enblend is currently the default blender. You can switch to verdandi.

Harry

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[T. Modes]

Hi Harry,

Am Montag, 1. Juni 2015 13:10:51 UTC+2 schrieb Harry van der Wolf:

I did some preliminary tests with verdandi(1), the new blender. In general it works fine, but in 2 panos I got "washed out" colors, maybe due to CIECAM colors in the originals (That comes to mind now that I type this mail. I will check tonight).

verdandi has no CIECAM mode. Verdandi does not modify the colors in the images. It take each pixel from one of the input images (as it is).
So for the washed out color I can image 3 causes.
1.) The input images have already washed out colors ;-)
2.) The remapped images have the washed out colors. In this case the photometric parameters are not optimal. In this case optimize the photometric parameters again to get a better match.
3.) Your input images have different icc profiles. In this case check the icc profiles and if they don't match fix this.

Thomas

[Gnome Nomad]

Ah, thanks.

To view this discussion on the web visit https://groups.google.com/d/msgid/hugin-ptx/CAGARPpuj_75PZD-pA%3Dx217aMnafy0Z69cVDCpyofYeHZJ5dfTg%40mail.gmail.com.

[Terry Duell]

Hello Harry,

On Mon, 01 Jun 2015 21:10:47 +1000, Harry van der Wolf <hvd...@gmail.com>
wrote:

> Hi,
>
> I did some preliminary tests with verdandi(1), the new blender. In
> general
> it works fine, but in 2 panos I got "washed out" colors, maybe due to
> CIECAM colors in the originals (That comes to mind now that I type this
> mail. I will check tonight).
>
> It is much faster then enblend, just like multiblend is/was.
>
> Some french website also paid attention to it:
> http://www.panophoto.org/forums/viewtopic.php?f=67&t=15190
>
> Are there any other users already with test results?
>

I have run a few tests, and it gives a good fast result for most. For my
tests it was faster than multiblend.
There are cases where it isn't as good, and an example of that is Paul
Womack's current map stitching project. The result shows quite noticeable
seams in areas of essentially plain colour.
Seams are not noticeable where the images have a lot of variation.

Cheers,
--
Regards,
Terry Duell

[Harry van der Wolf]

2015-06-02 0:35 GMT+02:00 Terry Duell <tdu...@iinet.net.au>:

Seams are not noticeable where the images have a lot of variation.

Cheers,
--
Regards,
Terry Duell

Hi Terry,

For me it is different. I do see seams where the color difference in the bottom half is big. 

For example: You have a nice even blue sky with forest/grass as "bottom half". However, in this bottom half is also a old "fortified farm" and some houses around having a completely different color then the forest/grass surrounding it. Then I get the seams.

I pointed to that french forum and actually the image they show is the same: lots of green and blue sky with a white building as part of the image and above the building the seams. Somehow verdandi does not (yet) compensate for those differences in colors (I think).

And w.r.t. the "washed out" colors: I was not able to rerun the tests again (I'm on a business trip), but all images had the same (icc) color profiles and the originals were OK. As the panos were simple straightforward panos I used Hugin completely on automode with both enblend and verdandi.

And a bug I think: I use a project and run the blending with enblend and afterwards close PTBatcherGUI. Then I change the blender to verdandi (integrated) from the preferences, save the project again rerun the stichting. Still enblend is used. I have to close Hugin and reopen it again to have it use verdandi.

Tomorrow I have more time and I will check more thoroughly also w.r.t. the "assumed" bug.

Harry

[T. Modes]

Hi Harry,

Am Dienstag, 2. Juni 2015 10:19:24 UTC+2 schrieb Harry van der Wolf:

And a bug I think: I use a project and run the blending with enblend and afterwards close PTBatcherGUI. Then I change the blender to verdandi (integrated) from the preferences, save the project again rerun the stichting. Still enblend is used. I have to close Hugin and reopen it again to have it use verdandi.

Tomorrow I have more time and I will check more thoroughly also w.r.t. the "assumed" bug.

I don't think that this is a bug. This could be a feature ;-). In the preferences you set the default blender, which is used for *new* projects (the same as the output format directly above). This is used when you create a new project afterwards. If you want to change the blender in an existing project, go to the stitcher tab and change the blender there. After saving the project file PTBatcherGUI should pick up the change for this project and use the chosen blender.

Thomas

Some background for verdandi: The inspiration come mainly from Pablos notes on the photometric optimization http://hugin.sourceforge.net/tech/ and my own observation, that the photometric correction results often in good results and there is no (big) blending needed for the final panorama. So the blender should take the content into account to fix some (smaller) parallax errors.
So when the fast preview windows show already a good panorama (without big color differences) then I got good results with verdandi. When you see more differences in the fast preview window then enblend is the better choice. So it depends on the given images which one is better. But there is the choice possible.
From the first tests it seems it works better for some sets and bad for other.
One cause I can imagine is the camera (or raw) settings. When the cam or the raw converter does apply some local image improvements (e.g. dynamic compression), then the effect changes above the image and this different for each image. This is something what the photometric optimizer can't handle.

[Rogier Wolff]

On Tue, Jun 02, 2015 at 10:52:27AM -0700, T. Modes wrote:
> Hi Harry,
>
> Am Dienstag, 2. Juni 2015 10:19:24 UTC+2 schrieb Harry van der Wolf:
> >
> >
> > And a bug I think: I use a project and run the blending with enblend and
> > afterwards close PTBatcherGUI. Then I change the blender to verdandi
> > (integrated) from the preferences, save the project again rerun the
> > stichting. Still enblend is used. I have to close Hugin and reopen it again
> > to have it use verdandi.
> >
> > Tomorrow I have more time and I will check more thoroughly also w.r.t. the
> > "assumed" bug.
> >
>
> I don't think that this is a bug. This could be a feature ;-). In the
> preferences you set the default blender, which is used for *new* projects
> (the same as the output format directly above). This is used when you
> create a new project afterwards. If you want to change the blender in an
> existing project, go to the stitcher tab and change the blender there.
> After saving the project file PTBatcherGUI should pick up the change for
> this project and use the chosen blender.

Can I make a suggestion? How about the blender setting in the
"stitcher tab" that is: add a "use the default blender". That setting
will use the current hugin default, unless changed. With a bit of
programming that would be: "hugin default blender: now enblend", or
"hugin default blender: now verdani".

I think that would work more intuitive for most users.

On the other hand.... If you save and reload such a setting, thereby
allowing the user to change the blender by changing the hugin-default,
then the results would depend on the current settings of the hugin
that opens the PTO. That might be undesirable for "reproducability".
(e.g. use hugin on the laptop to create a pano at half-res, then
move to bigger computer and restitch the project just with a higher
resolution....)

Still it is confusing for a user to say want to switch between
enblend and verdani, look around in the menus, find a setting where
you can choose between the two, and then..... nothing changes.

Roger.

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[John Eklund]

I tried Verdandi for the first time and it gave me highly visible seams compared to Enblend. Does it not use the multiresolution spline blending of Enblend?

To put it to the test I chose one of my most difficult blends yet - where I had backed up close to a wall and shot focus stacked images to try and keep it sharp. The focus stack is not perfect so some areas differ in sharpness and I had drawn alpha channel masks to favor the best parts of each image.

Did I do something wrong? I called it from the command prompt like this:

nona -m TIFF -o test_nona_verdandi test.pto

I also created a set of nona*.tif images and then called Verdandi and Enblend separately on them:

nona -o nona test.pto
enblend -v -m 18000 --output=test_enblend.tif nona*.tif
verdandi --output=test_verdandi.tif nona*

Calling Verdandi separately produced the same image as invoking it from nona with the -m TIFF flag. (Well almost - curiously, when comparing the images by subtracting one from the other, there are extremely subtle differences in a few pixels although completely invisible to the eye).

This is the same panorama I mentioned two years ago in the thread "Enblend: limiting minimum levels"
https://groups.google.com/forum/#!topic/hugin-ptx/qxxDjUT6XfY

/John in Sweden

Some of my work:
http://www.elmuseum.se/panorama/

[Bruno Postle]

On 22 September 2015 14:07:21 BST, John Eklund wrote:
>
>I tried Verdandi for the first time and it gave me highly visible seams
>
>compared to Enblend. Does it not use the multiresolution spline
>blending of Enblend?

Verdandi uses a 'hard' seam, so it works best where there is detail that it can follow, or where photometric/vignetting correction has achieved a very good match between photos already.

--
Bruno

--
Bruno

[Monkey]

A seam map export from Verdandi would be awesome. Then I could feed it into multiblend, since multiblend doesn't do seam optimisation.