Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Capturing and Editing Video > VirtualDub, VDubMod & AviDemux

Reply
 
Thread Tools Search this Thread Display Modes
Old 11th January 2020, 17:05   #41  |  Link
nji
Registered User
 
Join Date: Mar 2018
Location: Germany
Posts: 137
I'm referencing an idea of redfordxx
https://forum.doom9.org/showthread.p...61#post1894961
to enhance analysis phase of orig Deshaker.

On my attempts to understand the projection
shekh uses in his filter for accounting FOV...
and with my idea that it would be better to
account FOV BEFORE analysing phase...
https://forum.doom9.org/showthread.php?t=177335
...
I would like to propose to use exactly the "simple trig"
that shekh is using for his phase two
for pre analysis.

Example
If you have a movie with large FOV (say 90++)
project it "flat" (simple trig).
==> Will make it a pincushion und use that for analysis phase.

Both ideas should give more and better (wrt FOV) matchings.

RFC

Last edited by nji; 11th January 2020 at 17:11. Reason: Typo, ortho, otto
nji is offline   Reply With Quote
Old 13th January 2020, 08:55   #42  |  Link
redfordxx
Registered User
 
Join Date: Jan 2005
Location: Praha (not that one in Texas)
Posts: 863
I looked at LensTransform. It uses deshaker data gathered before transform and aplies them to video after transform? Is that correct?
EDIT: sorry, I missed thde point that log is bare guidance.

Last edited by redfordxx; 13th January 2020 at 09:14.
redfordxx is offline   Reply With Quote
Old 13th January 2020, 10:30   #43  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
I'll try to explain better:
given: log data describes movement
assume movement applies to image center exactly
find 3d rotation for entire projection which results in given movement of the center pixel.
Hope it makes sense now

edit:
Again, more precise way which I did not finish:
given: array of motion vectors
find 3d rotation which minimizes all(most) vectors
__________________
VirtualDub2

Last edited by shekh; 13th January 2020 at 10:34.
shekh is offline   Reply With Quote
Old 14th January 2020, 08:33   #44  |  Link
redfordxx
Registered User
 
Join Date: Jan 2005
Location: Praha (not that one in Texas)
Posts: 863
I again gave try to the lens profile and handedited it until I saw any change in the frame.

I ended up with two findings:
If I have perspectivemodel...no change...only fisheyemodel.

If I change the profile, I have to close the the VDub for changes to take effect.

Can you please confirm/explain/deny it?
redfordxx is offline   Reply With Quote
Old 14th January 2020, 13:41   #45  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
Yes, I wrote in first posts that only fisheye adobe profile is implemented.
Restart vdub: not really, it should reload presets every now and then. Open/close filter dialog, open/close Video->Filters dialog.
__________________
VirtualDub2
shekh is offline   Reply With Quote
Old 14th January 2020, 14:24   #46  |  Link
nji
Registered User
 
Join Date: Mar 2018
Location: Germany
Posts: 137
Quote:
Originally Posted by shekh View Post
Yes, I wrote in first posts that only fisheye adobe profile is implemented...
In a former post you adviced trying your filter for improving large FOV effects.
https://forum.doom9.org/showthread.p...32#post1895232

Does this hold only for fisheye lenses?
Or will it be an improvement for "normal" (rectingular) lenses too
(in comparison to orig Deshaker)?
EDIT
Might there be an enchancement to Lens Transform
so it does better for "normal" lenses?

Last edited by nji; 14th January 2020 at 17:06. Reason: see EDIT
nji is offline   Reply With Quote
Old 14th January 2020, 17:53   #47  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
For perfect rectilinear lens all you need to know is just fov parameter, there is nothing else to describe it.
Adobe profile creator defined 2 lens models but I implemented only "fisheye" because this is the one that fits hero etc.
Perspective model can be implemented too in theory, also profiles from other software can be implemented (like ptgui), or embedded gopro profiles, and so on.. as long as diagonal fov does not approach 180deg, at which point it is impossible to project it in rectilinear way.
In my filter I actually don't use any formula (like polinomial) but instead I use lookup table for distortion so it is basically profile/formula independent (but applying some 'standard' profiles requires knowledge how to interpret it and test samples - this is quite some work ).

Difference between Adobe "fisheye" model and "perspective" model is subtle, it is just the curvature formula which tighter fits actual lens. Same lens can be described by both models but you'll see more curvature errors in corners.

"Perspective" model assumes very little radial distortion. Small distortion is more difficult to test because, well, you dont see it
If you have it and want support, lets do this: post your 9 grid shots (full sensor) as required by lens creator and some exterior shots of very straight objects.
__________________
VirtualDub2
shekh is offline   Reply With Quote
Old 15th January 2020, 22:35   #48  |  Link
redfordxx
Registered User
 
Join Date: Jan 2005
Location: Praha (not that one in Texas)
Posts: 863
Quote:
Originally Posted by shekh View Post
For perfect rectilinear lens all you need to know is just fov parameter, there is nothing else to describe it.
So... when I get the parameters from PTGui:
FoV, a, b, c

I will defish.dll with a,b,c...

Then I use lens transform with FoV value, it sould be correct?
redfordxx is offline   Reply With Quote
Old 16th January 2020, 11:40   #49  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
Quote:
Originally Posted by redfordxx View Post
So... when I get the parameters from PTGui:
FoV, a, b, c

I will defish.dll with a,b,c...

Then I use lens transform with FoV value, it sould be correct?
Sounds good. A few notes:
I dont understand how defish uses fov parameter. It cant be both the angle and control distortion... Well, with a b c the fov is not used at all.
Similarly, defish does not tell you the new fov for resulting image.
So you should crop or scale the result in such way that pixels at positions (0,h/2) and (w,h/2) remain in same place. Otherwise you need to calculate the new fov yourself.

Link to defish for convenience
https://forum.doom9.org/showthread.p...26#post1375626
__________________
VirtualDub2
shekh is offline   Reply With Quote
Old 16th January 2020, 13:11   #50  |  Link
wonkey_monkey
Formerly davidh*****
 
wonkey_monkey's Avatar
 
Join Date: Jan 2004
Posts: 2,021
Quote:
I dont understand how defish uses fov parameter. It cant be both the angle and control distortion...
It is, because the input and output projections are assumed to be fisheye and rectilinear.

Having vaguely followed this rather meandering thread, I feel it's worth pointing out again that if the aim is to find a projection where 3D rotation can be eliminated by changing the projection, translating the image in 2D, and then changing the projection back, then no such projection exists.
__________________
My AviSynth filters / I'm the Doctor
wonkey_monkey is offline   Reply With Quote
Old 16th January 2020, 13:41   #51  |  Link
redfordxx
Registered User
 
Join Date: Jan 2005
Location: Praha (not that one in Texas)
Posts: 863
Quote:
Originally Posted by shekh View Post
Sounds good. A few notes:
I dont understand how defish uses fov parameter.
Uses only a b c
Quote:
Similarly, defish does not tell you the new fov for resulting image.
The defish adjustment is 12 black pixel in the corner.
So the resulting fov will be pretty much the same...or 1% change of the PTGui FoV.
Quote:
So you should crop or scale the result in such way that pixels at positions (0,h/2) and (w,h/2) remain in same place.
I do not follow.
I thought (w/2, h/2) should remain in the center.
redfordxx is offline   Reply With Quote
Old 16th January 2020, 13:42   #52  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
Quote:
Originally Posted by wonkey_monkey View Post
It is, because the input and output projections are assumed to be fisheye and rectilinear.
You mean in this fisheye model the "amount of barrel" is connected to fov? ok

Quote:
Originally Posted by wonkey_monkey View Post
if the aim is to find a projection where 3D rotation can be eliminated by changing the projection, translating the image in 2D, and then changing the projection back, then no such projection exists.
Just for fun: what if we allow 3 passes (one for each axis)
__________________
VirtualDub2
shekh is offline   Reply With Quote
Old 16th January 2020, 13:51   #53  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
Quote:
Originally Posted by redfordxx View Post
I thought (w/2, h/2) should remain in the center.
This is not what I wrote.

In this example fov is reduced (and no way to know how much).
__________________
VirtualDub2
shekh is offline   Reply With Quote
Old 16th January 2020, 14:13   #54  |  Link
wonkey_monkey
Formerly davidh*****
 
wonkey_monkey's Avatar
 
Join Date: Jan 2004
Posts: 2,021
By default, Defish keeps the centre of the image at the same scale. That means some cropping. This can be overridden by setting the "scaling" parameter to "fitx", "fity", or "fitxy".
__________________
My AviSynth filters / I'm the Doctor
wonkey_monkey is offline   Reply With Quote
Old 16th January 2020, 14:15   #55  |  Link
wonkey_monkey
Formerly davidh*****
 
wonkey_monkey's Avatar
 
Join Date: Jan 2004
Posts: 2,021
Quote:
Originally Posted by shekh View Post
Just for fun: what if we allow 3 passes (one for each axis)
Z is just a rotation of the image, so it doesn't need a "pass", but otherwise that might work. It's not very "pretty," though, when the image could be manipulated in one pass in 3D (to generate a 2D mapping).
__________________
My AviSynth filters / I'm the Doctor
wonkey_monkey is offline   Reply With Quote
Old 16th January 2020, 14:31   #56  |  Link
nji
Registered User
 
Join Date: Mar 2018
Location: Germany
Posts: 137
Quote:
Originally Posted by wonkey_monkey View Post
...

Having vaguely followed this rather meandering thread
... yes, that's pretty true :-)

I can only speak for myself ... of course.

And I used orig Deshaker since some time to my very satisfaction.
Actually get kind of "addicted" to it ...
as a calm camera is a relieve when watching.

However I made the observation that if the movie has been taken
by a lens with large fov then the result of orig Deshaker
sometimes is worse than the shaky original movie (like on LSD etc. )
Clearly that is because Deshaker assumes/ works 2D only.

So the simple question was if it would be possible to take
into account the 3D origin of the movie somehow for large fovs.

Your DeShaker3D obviously does it although it has some severe
drawbacks (if I get it right)
https://forum.doom9.org/showthread.p...58#post1895158

I thought that Lens Transform would do better.
Lens Transform is also for the specific distortions of lenses,
but personally I'm not about enhancing of a device I own,
but about older movies where I only can tell roughly fov.
And with that indoor movies (family feasts etc.)
obviously taken with larger fov (but not fisheye),
Lens Transform does't do good either.
It does good for fisheye ... to my experience.
I cannot tell what's the reason for that.
Is it "by design" as to the fisheye projection?
(And if ... could it be improved by offering for "normal lenses" too?)
Or is it because panning and tilting (redfordxx called it rotation x and y)
have more effects the larger the fov?

All in all ... just a simple question from my side:

How do I deshake large fov (not fisheye) movies?
If not possible with up to now:
Which improvements could be done ...
(at Lens Transform ... as the alternatives do not do (?))
nji is offline   Reply With Quote
Old 16th January 2020, 16:16   #57  |  Link
shekh
Registered User
 
Join Date: Mar 2015
Posts: 756
nji
"doesn't do good" is void discussion unless you demonstrate specific shots and results.
In pure math adding fisheye is more complex so "flat" lens can't be worse. But the perceived quality can be ruined by many factors which are subject to research.
Are you trying to find real software for the job? Have you tried Mercalli or anything else?
__________________
VirtualDub2
shekh is offline   Reply With Quote
Old 16th January 2020, 16:41   #58  |  Link
nji
Registered User
 
Join Date: Mar 2018
Location: Germany
Posts: 137
Quote:
Originally Posted by shekh View Post
"doesn't do good" is void discussion unless you demonstrate specific shots and results.
I think it is well known what kind of "wobbling", "LSD-effect" you get when deshaking large fov movies.

Quote:
Originally Posted by shekh View Post
In pure math adding fisheye is more complex so "flat" lens can't be worse.
I do not agree.
It is not: The more complex the better.
It is: The more suitable the better,

Quote:
Originally Posted by shekh View Post
But the perceived quality can be ruined by many factors which are subject to research.
Don't believe that either.
I'm pretty sure it's simple projection math (I sadly am not able to).
Research ... in the 17th century perhaps

Quote:
Originally Posted by shekh View Post
Are you trying to find real software for the job? Have you tried Mercalli or anything else?
What do you mean by: "real software"?
Only software that costs LOTS of money shall be taken serious?
nji is offline   Reply With Quote
Old 16th January 2020, 16:45   #59  |  Link
poisondeathray
Registered User
 
Join Date: Sep 2007
Posts: 4,365
Quote:
Originally Posted by nji View Post
I think it is well known what kind of "wobbling", "LSD-effect" you get when deshaking large fov movies.
Did you mean rolling shutter artifacts ?

Or that the "wobbling" was introduced by the compensatory stabilization method ?

What kind of "wobbling?" exactly ? There are different types .

Or some combination?
poisondeathray is offline   Reply With Quote
Old 16th January 2020, 17:17   #60  |  Link
nji
Registered User
 
Join Date: Mar 2018
Location: Germany
Posts: 137
Quote:
Originally Posted by poisondeathray View Post
Did you mean rolling shutter artifacts ?

Or that the "wobbling" was introduced by the compensatory stabilization method ?

What kind of "wobbling?" exactly ? There are different types .

Or some combination?
Try to deshake a global shutter large fov movie...
to see what this thread is about.
nji is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 18:18.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.