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Stereo distortions in stereo panoramas

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Stereo distortions in stereo panoramas

panovrx-2
http://portal.acm.org/citation.cfm?id=1823743
and
http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
.. see "Acquisition of stereo panoramas for display in VR environments"

these papers look to have interesting potential for the discussion of the distortions you get (vertical parallax seems to me to be the main one) with very wide angle and views up and down with stereo panoramas showed and captured the usual ways.

Here is a new test stereo panorama (anaglyph) of a street scene with about 9cm separation at a height of about 2m
("The typical pupillary distance for adults is around 54–68 mm")
http://www.mediavr.com/rocksbridgeana.htm

This is 7200 by 3600 -- with greater resolution the furthest discriminable depth would be greater but with  this anaglyph version for me most depth seems to disappear at about 50m. You see a lot more depth than anaglyph with most 3d displays -- say a Zalman 24" horizontally interlaced, but basically this looks kind of flat to me for an exterior scene as anaglyph.

I shot this with 2 Canon5DmkII + 10.5Nikkor at f4.5 approx with 74 shots per camera with spliced cable releases with a Hahnel wireless timer remote at 1 fps. (The Hahnel is handy for this as you can input total frame count you want). I used a very sturdy rotator base for this on a tripod and optimized using the mask function in PTGui to exclude close (foreground) scene features. I used a few mask elements too in the stitching to remove moving cars etc.  (Continuous rotation, exposure time, 1/160th sec). With a 74sec rotation you can use shutter speeds as slow as about 1/60th which makes this a very convenient way of shooting many kinds of stereo interiors in about a minute (74 shots is enough if the nearest feature is no closer than a meter). The stereo is a bit strong for very small rooms but for large rooms it looks great. But, as I say, for exteriors this separation -- 9cm  (the closest I can get with these cameras) is a bit flat.

PeterM




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RE: Stereo distortions in stereo panoramas

Yazan Sboul

I love this! Peter you are a genius! I happen to have a pair of 3d glasses for this, and with a bit of colour correction on the screen it looks awesome!

Can we have a more detailed tutorial on how to do this? Are there any links. I considered this a while back, I figured out the distance between cameras and a simple rig, but I never got round to doing it. The main reason was that I was thinking in terms of 5-6 shots around, and it seemed to me that the final shot would not match up!
Is this why you do so many shots? - does it average out any errors throughout the image?
Thanks for sharing this looks amazing. I wonder if it has any commercial value. I guess a 3d panoramic video is the next step.
Y.S
To: [hidden email]
From: [hidden email]
Date: Sun, 30 Jan 2011 00:03:56 +0000
Subject: [PanoToolsNG] Stereo distortions in stereo panoramas


















 



 


   
     
     
      http://portal.acm.org/citation.cfm?id=1823743

and

http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449

.. see "Acquisition of stereo panoramas for display in VR environments"



these papers look to have interesting potential for the discussion of the distortions you get (vertical parallax seems to me to be the main one) with very wide angle and views up and down with stereo panoramas showed and captured the usual ways.



Here is a new test stereo panorama (anaglyph) of a street scene with about 9cm separation at a height of about 2m

("The typical pupillary distance for adults is around 54–68 mm")

http://www.mediavr.com/rocksbridgeana.htm



This is 7200 by 3600 -- with greater resolution the furthest discriminable depth would be greater but with  this anaglyph version for me most depth seems to disappear at about 50m. You see a lot more depth than anaglyph with most 3d displays -- say a Zalman 24" horizontally interlaced, but basically this looks kind of flat to me for an exterior scene as anaglyph.



I shot this with 2 Canon5DmkII + 10.5Nikkor at f4.5 approx with 74 shots per camera with spliced cable releases with a Hahnel wireless timer remote at 1 fps. (The Hahnel is handy for this as you can input total frame count you want). I used a very sturdy rotator base for this on a tripod and optimized using the mask function in PTGui to exclude close (foreground) scene features. I used a few mask elements too in the stitching to remove moving cars etc.  (Continuous rotation, exposure time, 1/160th sec). With a 74sec rotation you can use shutter speeds as slow as about 1/60th which makes this a very convenient way of shooting many kinds of stereo interiors in about a minute (74 shots is enough if the nearest feature is no closer than a meter). The stereo is a bit strong for very small rooms but for large rooms it looks great. But, as I say, for exteriors this separation -- 9cm  (the closest I can get with these cameras) is a bit flat.



PeterM





   
     

   
   






       

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Re: Stereo distortions in stereo panoramas

enridp
In reply to this post by panovrx-2
Hi Peter!
You and Wim are the kings of stereo pano, I always enjoy your comments and news about these techniques.
But I can't understand why if you are using two cameras you need anyway a lot of pictures (75), is not possible with... I don't know, 6 shoots (each camera)?

Also, I see what you mean with distorted views when seeing with a high FOV. The red is very distorted and breaks the ilusion.
When I look with this angle:
http://www.imagengratis.org/images/stereoretinal.jpg
I feel retinal rivality with the red car.
But it's OK in this view:
http://www.imagengratis.org/images/stereook.jpg

And this is a great stereo!:
http://www.imagengratis.org/images/greatstereo.jpg


Regards!
Enrique.

--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
> http://portal.acm.org/citation.cfm?id=1823743
> and
> http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
> .. see "Acquisition of stereo panoramas for display in VR environments"
>
> these papers look to have interesting potential for the discussion of the distortions you get (vertical parallax seems to me to be the main one) with very wide angle and views up and down with stereo panoramas showed and captured the usual ways.
>
> Here is a new test stereo panorama (anaglyph) of a street scene with about 9cm separation at a height of about 2m
> ("The typical pupillary distance for adults is around 54–68 mm")
> http://www.mediavr.com/rocksbridgeana.htm
>
> This is 7200 by 3600 -- with greater resolution the furthest discriminable depth would be greater but with  this anaglyph version for me most depth seems to disappear at about 50m. You see a lot more depth than anaglyph with most 3d displays -- say a Zalman 24" horizontally interlaced, but basically this looks kind of flat to me for an exterior scene as anaglyph.
>
> I shot this with 2 Canon5DmkII + 10.5Nikkor at f4.5 approx with 74 shots per camera with spliced cable releases with a Hahnel wireless timer remote at 1 fps. (The Hahnel is handy for this as you can input total frame count you want). I used a very sturdy rotator base for this on a tripod and optimized using the mask function in PTGui to exclude close (foreground) scene features. I used a few mask elements too in the stitching to remove moving cars etc.  (Continuous rotation, exposure time, 1/160th sec). With a 74sec rotation you can use shutter speeds as slow as about 1/60th which makes this a very convenient way of shooting many kinds of stereo interiors in about a minute (74 shots is enough if the nearest feature is no closer than a meter). The stereo is a bit strong for very small rooms but for large rooms it looks great. But, as I say, for exteriors this separation -- 9cm  (the closest I can get with these cameras) is a bit flat.
>
> PeterM
>


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Re: Stereo distortions in stereo panoramas

panovrx-2
Here is an example of a couple of the stereo distortions I was thinking of:
http://www.mediavr.com/verticaldisparity1.jpg

You see the vertical separation of non-central features is extreme. It should be zero. Notice also the much exaggerated horizontal disparity in that part of the picture. This is too extreme to resolve so effectively the lateral periphery of all stereo panoramas viewed the usually warped ways  are too separated to view. This is regardless of whether you use anaglyph, interlaced etc viewing methods. If the panorama is unwarped (ie. not rendered as a steerable view), eg. anaglyph equirectangular then these distortions do not exist but of course the view is unrealistic in other ways.

The Abstract linked to the item on "Acquisition of stereo panoramas for display in VR environments" on  

http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449

seems to say they have worked out a solution for this.

Here is another street panorama
http://www.mediavr.com/thana1bana.htm
.. on a pole at about 4m with twin5d/10.5mm 50 shots in 12 sec at about 20cm separation (jpg because the camera cant do a fast 50 shot burst in Raw). To the left of the stairs there is a stitch error which I couldnt fix (the pole moved around too much I think) .. in 2d it would be fixable but that kind of stitching fixing is much harder to do perfectly in stereo sometimes.

Peter






--- In [hidden email], "enridp" <enridp@...> wrote:

> But I can't understand why if you are using two cameras you need anyway a lot of pictures (75), is not possible with... I don't know, 6 shoots (each camera)?
>
> Also, I see what you mean with distorted views when seeing with a high FOV. The red is very distorted and breaks the ilusion.
> When I look with this angle:
> http://www.imagengratis.org/images/stereoretinal.jpg
> I feel retinal rivality with the red car.
> But it's OK in this view:
> http://www.imagengratis.org/images/stereook.jpg
>
> And this is a great stereo!:
> http://www.imagengratis.org/images/greatstereo.jpg
>
>
> Regards!
> Enrique.
>
> --- In [hidden email], "panovrx" <panovrx@> wrote:
> >
> > http://portal.acm.org/citation.cfm?id=1823743
> > and
> > http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
> > .. see "Acquisition of stereo panoramas for display in VR environments"
> >
> > these papers look to have interesting potential for the discussion of the distortions you get (vertical parallax seems to me to be the main one) with very wide angle and views up and down with stereo panoramas showed and captured the usual ways.
> >
> > Here is a new test stereo panorama (anaglyph) of a street scene with about 9cm separation at a height of about 2m
> > ("The typical pupillary distance for adults is around 54–68 mm")
> > http://www.mediavr.com/rocksbridgeana.htm
> >
> > This is 7200 by 3600 -- with greater resolution the furthest discriminable depth would be greater but with  this anaglyph version for me most depth seems to disappear at about 50m. You see a lot more depth than anaglyph with most 3d displays -- say a Zalman 24" horizontally interlaced, but basically this looks kind of flat to me for an exterior scene as anaglyph.
> >
> > I shot this with 2 Canon5DmkII + 10.5Nikkor at f4.5 approx with 74 shots per camera with spliced cable releases with a Hahnel wireless timer remote at 1 fps. (The Hahnel is handy for this as you can input total frame count you want). I used a very sturdy rotator base for this on a tripod and optimized using the mask function in PTGui to exclude close (foreground) scene features. I used a few mask elements too in the stitching to remove moving cars etc.  (Continuous rotation, exposure time, 1/160th sec). With a 74sec rotation you can use shutter speeds as slow as about 1/60th which makes this a very convenient way of shooting many kinds of stereo interiors in about a minute (74 shots is enough if the nearest feature is no closer than a meter). The stereo is a bit strong for very small rooms but for large rooms it looks great. But, as I say, for exteriors this separation -- 9cm  (the closest I can get with these cameras) is a bit flat.
> >
> > PeterM
> >
>


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Re: Stereo distortions in stereo panoramas

Sacha Griffin
Thanks a great stereo one, I almost don't see any fringing issues.

Except for that one slice, that's a super job. I just got my glasses
recently so these are a whole lot more fun to view now! ;)

I wonder if you can import these into a 3d max or something to fix 3d
issues.

 

s

 

From: [hidden email] [mailto:[hidden email]] On
Behalf Of panovrx
Sent: Monday, January 31, 2011 5:51 PM
To: [hidden email]
Subject: [PanoToolsNG] Re: Stereo distortions in stereo panoramas

 

 

Here is an example of a couple of the stereo distortions I was thinking of:
http://www.mediavr.com/verticaldisparity1.jpg

You see the vertical separation of non-central features is extreme. It
should be zero. Notice also the much exaggerated horizontal disparity in
that part of the picture. This is too extreme to resolve so effectively the
lateral periphery of all stereo panoramas viewed the usually warped ways are
too separated to view. This is regardless of whether you use anaglyph,
interlaced etc viewing methods. If the panorama is unwarped (ie. not
rendered as a steerable view), eg. anaglyph equirectangular then these
distortions do not exist but of course the view is unrealistic in other
ways.

The Abstract linked to the item on "Acquisition of stereo panoramas for
display in VR environments" on

http://spie.org//app/program/index.cfm?fuseaction=conferencedetail
<http://spie.org/app/program/index.cfm?fuseaction=conferencedetail&export_id
=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&prog
ramtrack_id=931449>
&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=9
25953&programtrack_id=931449

seems to say they have worked out a solution for this.

Here is another street panorama
http://www.mediavr.com/thana1bana.htm
.. on a pole at about 4m with twin5d/10.5mm 50 shots in 12 sec at about 20cm
separation (jpg because the camera cant do a fast 50 shot burst in Raw). To
the left of the stairs there is a stitch error which I couldnt fix (the pole
moved around too much I think) .. in 2d it would be fixable but that kind of
stitching fixing is much harder to do perfectly in stereo sometimes.

Peter



.

 
<http://geo.yahoo.com/serv?s=97359714/grpId=18227848/grpspId=1705006496/msgI
d=47787/stime=1296514274/nc1=4836041/nc2=3848642/nc3=4025373>





[Non-text portions of this message have been removed]

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Re: Stereo distortions in stereo panoramas

enridp
In reply to this post by panovrx-2
Peter can you teach me why we need so many shoots even with two cameras? I'm really confused by that.
I was thinking that using two cameras had two advantages over the method with one camera:
1) You can shoot less pictures (<10) and therefore, faster.
2) You can take action panoramas because you are making the 3D from two images taked at the same time.

Now the first seems to be wrong, but I don't know why :(

Thanks !
Enrique.


--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
> Here is an example of a couple of the stereo distortions I was thinking of:
> http://www.mediavr.com/verticaldisparity1.jpg
>
> You see the vertical separation of non-central features is extreme. It should be zero. Notice also the much exaggerated horizontal disparity in that part of the picture. This is too extreme to resolve so effectively the lateral periphery of all stereo panoramas viewed the usually warped ways  are too separated to view. This is regardless of whether you use anaglyph, interlaced etc viewing methods. If the panorama is unwarped (ie. not rendered as a steerable view), eg. anaglyph equirectangular then these distortions do not exist but of course the view is unrealistic in other ways.
>
> The Abstract linked to the item on "Acquisition of stereo panoramas for display in VR environments" on  
>
> http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
>
> seems to say they have worked out a solution for this.
>
> Here is another street panorama
> http://www.mediavr.com/thana1bana.htm
> .. on a pole at about 4m with twin5d/10.5mm 50 shots in 12 sec at about 20cm separation (jpg because the camera cant do a fast 50 shot burst in Raw). To the left of the stairs there is a stitch error which I couldnt fix (the pole moved around too much I think) .. in 2d it would be fixable but that kind of stitching fixing is much harder to do perfectly in stereo sometimes.
>
> Peter
>
>
>
>
>
>
> --- In [hidden email], "enridp" <enridp@> wrote:
>
> > But I can't understand why if you are using two cameras you need anyway a lot of pictures (75), is not possible with... I don't know, 6 shoots (each camera)?
> >
> > Also, I see what you mean with distorted views when seeing with a high FOV. The red is very distorted and breaks the ilusion.
> > When I look with this angle:
> > http://www.imagengratis.org/images/stereoretinal.jpg
> > I feel retinal rivality with the red car.
> > But it's OK in this view:
> > http://www.imagengratis.org/images/stereook.jpg
> >
> > And this is a great stereo!:
> > http://www.imagengratis.org/images/greatstereo.jpg
> >
> >
> > Regards!
> > Enrique.
> >
> > --- In [hidden email], "panovrx" <panovrx@> wrote:
> > >
> > > http://portal.acm.org/citation.cfm?id=1823743
> > > and
> > > http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
> > > .. see "Acquisition of stereo panoramas for display in VR environments"
> > >
> > > these papers look to have interesting potential for the discussion of the distortions you get (vertical parallax seems to me to be the main one) with very wide angle and views up and down with stereo panoramas showed and captured the usual ways.
> > >
> > > Here is a new test stereo panorama (anaglyph) of a street scene with about 9cm separation at a height of about 2m
> > > ("The typical pupillary distance for adults is around 54–68 mm")
> > > http://www.mediavr.com/rocksbridgeana.htm
> > >
> > > This is 7200 by 3600 -- with greater resolution the furthest discriminable depth would be greater but with  this anaglyph version for me most depth seems to disappear at about 50m. You see a lot more depth than anaglyph with most 3d displays -- say a Zalman 24" horizontally interlaced, but basically this looks kind of flat to me for an exterior scene as anaglyph.
> > >
> > > I shot this with 2 Canon5DmkII + 10.5Nikkor at f4.5 approx with 74 shots per camera with spliced cable releases with a Hahnel wireless timer remote at 1 fps. (The Hahnel is handy for this as you can input total frame count you want). I used a very sturdy rotator base for this on a tripod and optimized using the mask function in PTGui to exclude close (foreground) scene features. I used a few mask elements too in the stitching to remove moving cars etc.  (Continuous rotation, exposure time, 1/160th sec). With a 74sec rotation you can use shutter speeds as slow as about 1/60th which makes this a very convenient way of shooting many kinds of stereo interiors in about a minute (74 shots is enough if the nearest feature is no closer than a meter). The stereo is a bit strong for very small rooms but for large rooms it looks great. But, as I say, for exteriors this separation -- 9cm  (the closest I can get with these cameras) is a bit flat.
> > >
> > > PeterM
> > >
> >
>


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Re: Stereo distortions in stereo panoramas

enridp
In reply to this post by panovrx-2
Also, I don't see any error in this panorama, it looks really great.
And about the stereo distortions, I don't see too much problem on it, because it's really appreciable with extreme FOV, and even in normal panoramas the image looks really ugly in those FOVs.
Have you tried using Krpano fisheye option for big FOVs?
Anyway, I think the best solution is to limit the FOV, the normal human FOV is about 100º, Google StreetView's max FOV I think is 120 or 110.

I think there's an extra and more important problem with extreme FOV, there are many people who feels nausea when moving the panorama.
And Anaglyph causes a headache in a lot of people, so if we combine those things we could kill someone :P


--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
> Here is an example of a couple of the stereo distortions I was thinking of:
> http://www.mediavr.com/verticaldisparity1.jpg
>
> You see the vertical separation of non-central features is extreme. It should be zero. Notice also the much exaggerated horizontal disparity in that part of the picture. This is too extreme to resolve so effectively the lateral periphery of all stereo panoramas viewed the usually warped ways  are too separated to view. This is regardless of whether you use anaglyph, interlaced etc viewing methods. If the panorama is unwarped (ie. not rendered as a steerable view), eg. anaglyph equirectangular then these distortions do not exist but of course the view is unrealistic in other ways.
>
> The Abstract linked to the item on "Acquisition of stereo panoramas for display in VR environments" on  
>
> http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
>
> seems to say they have worked out a solution for this.
>
> Here is another street panorama
> http://www.mediavr.com/thana1bana.htm
> .. on a pole at about 4m with twin5d/10.5mm 50 shots in 12 sec at about 20cm separation (jpg because the camera cant do a fast 50 shot burst in Raw). To the left of the stairs there is a stitch error which I couldnt fix (the pole moved around too much I think) .. in 2d it would be fixable but that kind of stitching fixing is much harder to do perfectly in stereo sometimes.
>
> Peter
>
>
>
>
>
>
> --- In [hidden email], "enridp" <enridp@> wrote:
>
> > But I can't understand why if you are using two cameras you need anyway a lot of pictures (75), is not possible with... I don't know, 6 shoots (each camera)?
> >
> > Also, I see what you mean with distorted views when seeing with a high FOV. The red is very distorted and breaks the ilusion.
> > When I look with this angle:
> > http://www.imagengratis.org/images/stereoretinal.jpg
> > I feel retinal rivality with the red car.
> > But it's OK in this view:
> > http://www.imagengratis.org/images/stereook.jpg
> >
> > And this is a great stereo!:
> > http://www.imagengratis.org/images/greatstereo.jpg
> >
> >
> > Regards!
> > Enrique.
> >
> > --- In [hidden email], "panovrx" <panovrx@> wrote:
> > >
> > > http://portal.acm.org/citation.cfm?id=1823743
> > > and
> > > http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
> > > .. see "Acquisition of stereo panoramas for display in VR environments"
> > >
> > > these papers look to have interesting potential for the discussion of the distortions you get (vertical parallax seems to me to be the main one) with very wide angle and views up and down with stereo panoramas showed and captured the usual ways.
> > >
> > > Here is a new test stereo panorama (anaglyph) of a street scene with about 9cm separation at a height of about 2m
> > > ("The typical pupillary distance for adults is around 54–68 mm")
> > > http://www.mediavr.com/rocksbridgeana.htm
> > >
> > > This is 7200 by 3600 -- with greater resolution the furthest discriminable depth would be greater but with  this anaglyph version for me most depth seems to disappear at about 50m. You see a lot more depth than anaglyph with most 3d displays -- say a Zalman 24" horizontally interlaced, but basically this looks kind of flat to me for an exterior scene as anaglyph.
> > >
> > > I shot this with 2 Canon5DmkII + 10.5Nikkor at f4.5 approx with 74 shots per camera with spliced cable releases with a Hahnel wireless timer remote at 1 fps. (The Hahnel is handy for this as you can input total frame count you want). I used a very sturdy rotator base for this on a tripod and optimized using the mask function in PTGui to exclude close (foreground) scene features. I used a few mask elements too in the stitching to remove moving cars etc.  (Continuous rotation, exposure time, 1/160th sec). With a 74sec rotation you can use shutter speeds as slow as about 1/60th which makes this a very convenient way of shooting many kinds of stereo interiors in about a minute (74 shots is enough if the nearest feature is no closer than a meter). The stereo is a bit strong for very small rooms but for large rooms it looks great. But, as I say, for exteriors this separation -- 9cm  (the closest I can get with these cameras) is a bit flat.
> > >
> > > PeterM
> > >
> >
>


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Re: Stereo distortions in stereo panoramas

panovrx-2
In reply to this post by enridp

--- In [hidden email], "enridp" <enridp@...> wrote:
>
> Peter can you teach me why we need so many shoots even with two cameras? I'm really confused by that.
> I was thinking that using two cameras had two advantages over the method with one camera:
> 1) You can shoot less pictures (<10) and therefore, faster.
> 2) You can take action panoramas because you are making the 3D from two images taked at the same time.
>
>
Panoramas must be stitched from images taken from approximately the same point in space. So with a normal panorama you need to find the No Parallax Point and rotate the camera round that point. With a 2 camera  stereo rig both cameras are rotating around a point between them -- neither are rotating around any where near their NPPs. So to minimize the resultant parallax errors between the successive shots for each camera you need lots of shots and just use a central slice from each shot to blend to make the L and R panoramas. The closer the subject to the cameras the more shots you need -- somewhere between 30 and 300 maybe.

PeterM

PeterM

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Re: Stereo distortions in stereo panoramas

enridp
I see, thanks Peter for the explanation!
So... if we are shooting far objects, like a landscape, could we shoot only the common 4 images (for sigma8mm) for example?
Or shooting less pictures has another disadvantage in addition to parallax errors (for near objects)?

Regards !
Enrique.

--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
>
> --- In [hidden email], "enridp" <enridp@> wrote:
> >
> > Peter can you teach me why we need so many shoots even with two cameras? I'm really confused by that.
> > I was thinking that using two cameras had two advantages over the method with one camera:
> > 1) You can shoot less pictures (<10) and therefore, faster.
> > 2) You can take action panoramas because you are making the 3D from two images taked at the same time.
> >
> >
> Panoramas must be stitched from images taken from approximately the same point in space. So with a normal panorama you need to find the No Parallax Point and rotate the camera round that point. With a 2 camera  stereo rig both cameras are rotating around a point between them -- neither are rotating around any where near their NPPs. So to minimize the resultant parallax errors between the successive shots for each camera you need lots of shots and just use a central slice from each shot to blend to make the L and R panoramas. The closer the subject to the cameras the more shots you need -- somewhere between 30 and 300 maybe.
>
> PeterM
>
> PeterM
>


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Re: Stereo distortions in stereo panoramas

Yazan Sboul

I feel like I'm answering questions no one has asked me. But hey -  I guess it would be wise to shoot at least 20, even with a landscape. However, the rule is quite robust ;  the further the object is the less overlap you need and in theory you can get away with the normal overlap of 4 to 6 shots.  

To: [hidden email]
From: [hidden email]
Date: Tue, 1 Feb 2011 14:07:00 +0000
Subject: [PanoToolsNG] Re: Stereo distortions in stereo panoramas


















 



 


   
     
     
      I see, thanks Peter for the explanation!

So... if we are shooting far objects, like a landscape, could we shoot only the common 4 images (for sigma8mm) for example?

Or shooting less pictures has another disadvantage in addition to parallax errors (for near objects)?



Regards !

Enrique.



--- In [hidden email], "panovrx" <panovrx@...> wrote:

>

>

> --- In [hidden email], "enridp" <enridp@> wrote:

> >

> > Peter can you teach me why we need so many shoots even with two cameras? I'm really confused by that.

> > I was thinking that using two cameras had two advantages over the method with one camera:

> > 1) You can shoot less pictures (<10) and therefore, faster.

> > 2) You can take action panoramas because you are making the 3D from two images taked at the same time.

> >

> >

> Panoramas must be stitched from images taken from approximately the same point in space. So with a normal panorama you need to find the No Parallax Point and rotate the camera round that point. With a 2 camera  stereo rig both cameras are rotating around a point between them -- neither are rotating around any where near their NPPs. So to minimize the resultant parallax errors between the successive shots for each camera you need lots of shots and just use a central slice from each shot to blend to make the L and R panoramas. The closer the subject to the cameras the more shots you need -- somewhere between 30 and 300 maybe.

>

> PeterM

>

> PeterM

>





   
     

   
   






       

[Non-text portions of this message have been removed]



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Re: Stereo distortions in stereo panoramas

panovrx-2
In reply to this post by panovrx-2
For single camera (off-axis l/r slice assembly) stereo pano sweep capture Sony now has a rival -- Morpho, Inc (shades of the Matrix)
http://www.morphoinc.com/en/products/Panorama3D.html


--- In [hidden email], "panovrx" <panovrx@...> wrote:

>
> Here is an example of a couple of the stereo distortions I was thinking of:
> http://www.mediavr.com/verticaldisparity1.jpg
>
> You see the vertical separation of non-central features is extreme. It should be zero. Notice also the much exaggerated horizontal disparity in that part of the picture. This is too extreme to resolve so effectively the lateral periphery of all stereo panoramas viewed the usually warped ways  are too separated to view. This is regardless of whether you use anaglyph, interlaced etc viewing methods. If the panorama is unwarped (ie. not rendered as a steerable view), eg. anaglyph equirectangular then these distortions do not exist but of course the view is unrealistic in other ways.
>
> The Abstract linked to the item on "Acquisition of stereo panoramas for display in VR environments" on  
>
> http://spie.org//app/program/index.cfm?fuseaction=conferencedetail&export_id=x16280&ID=x16223&redir=x16223.xml&conference_id=927621&event_id=925953&programtrack_id=931449
>
> seems to say they have worked out a solution for this.
>
> Here is another street panorama
> http://www.mediavr.com/thana1bana.htm
> .. on a pole at about 4m with twin5d/10.5mm 50 shots in 12 sec at about 20cm separation (jpg because the camera cant do a fast 50 shot burst in Raw). To the left of the stairs there is a stitch error which I couldnt fix (the pole moved around too much I think) .. in 2d it would be fixable but that kind of stitching fixing is much harder to do perfectly in stereo sometimes.
>
> Peter
>
>
>
>
>
>


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Re: Stereo distortions in stereo panoramas

Roger D Williams
On Wed, 02 Feb 2011 07:51:27 +0900, panovrx <[hidden email]> wrote:

> For single camera (off-axis l/r slice assembly) stereo pano sweep  
> capture Sony now has a rival -- Morpho, Inc (shades of the Matrix)
> http://www.morphoinc.com/en/products/Panorama3D.html

Thanks, Peter. Their work is most impressive. I must admit my first
reaction on discovering that they were based in Tokyo, within easy
reach from our condo, was that they might have need of my
translation skills! It would be fun to work on such leading-edge
technology.

Roger W.

--
Work: www.adex-japan.com
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Re: Stereo distortions in stereo panoramas

Wim Koornneef
In reply to this post by enridp
enridp wrote
... if we are shooting far objects, like a landscape, could we shoot only the common 4 images (for sigma8mm) for example?...
Hello Enrique,

For a 3D pano with no objects closeby and only far away objects you have to seperate the camera lenses wider to get more parallax otherwise there is no depth in the 3D view.

So instead of 9 cm, 25, 50 cm or even more lens seperation, depending on the distance to far away objects, can be needed.
With such extreme lens seperations (hyper stereo) the NPP off set is really, really huge and with just 4 images around it will cause huge stitch errors in each of the left and right pano.
To tackle this probem you really have to shoot a lot more then 4 images.

In general; the more images you shoot the smaller the stitch errors will be, this is because the total amount of parallax error wil be evenly spread over all images. The number of images that are needed depends on the amount of stitching errors that *you* find acceptable......

Wim
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Re: Stereo distortions in stereo panoramas

enridp
Thanks Wim !!!
You are right about the extra separation (and hence the extra parallax error) needed for very far objects.

But I'm a bit confused now of why earthmine is using two cameras, and with big separation:

http://www.freeimagehosting.net/image.php?3f93db70f8.jpg

They have the best "street view" system in the market I think, with a very accurate 3D (although there are only videos about earthmine, I couldn't find any online demo or something like that).



--- In [hidden email], Wim Koornneef <wim.koornneef@...> wrote:

>
>
>
> enridp wrote:
> > ... if we are shooting far objects, like a landscape, could we shoot only
> > the common 4 images (for sigma8mm) for example?...
>
> Hello Enrique,
>
> For a 3D pano with no objects closeby and only far away objects you have to
> seperate the camera lenses wider to get more parallax otherwise there is no
> depth in the 3D view.
>
> So instead of 9 cm, 25, 50 cm or even more lens seperation, depending on the
> distance to far away objects, can be needed.
> With such extreme lens seperations (hyper stereo) the NPP off set is really,
> really huge and with just 4 images around it will cause huge stitch errors
> in each of the left and right pano.
> To tackle this probem you really have to shoot a lot more then 4 images.
>
> In general; the more images you shoot the smaller the stitch errors will be,
> this is because the total amount of parallax error wil be evenly spread over
> all images. The number of images that are needed depends on the amount of
> stitching errors that *you* find acceptable......
>
> Wim
> --
> View this message in context: http://panotoolsng.586017.n4.nabble.com/Stereo-distortions-in-stereo-panoramas-tp3246722p3253601.html
> Sent from the PanoToolsNG mailing list archive at Nabble.com.
>


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Re: Stereo distortions in stereo panoramas

Aldo Hoeben
> But I'm a bit confused now of why earthmine is using two cameras,
> and with big separation:
>
> http://www.freeimagehosting.net/image.php?3f93db70f8.jpg

That's not for stereo, but for accurately measuring distances through triangulation. Note that *your* eyes are arranged in a horizontal configuration.

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Re: Stereo distortions in stereo panoramas

enridp
Yes, but why is so important the orientation of the camera?, you can rotate your head 90 degrees and still viewing in 3D.
Is not possible to arrage the camera in a vertical configuration like earthmine? in tha way we will be rotating both cameras from their NPP.



--- In [hidden email], "Aldo Hoeben" <aldo@...> wrote:
>
> > But I'm a bit confused now of why earthmine is using two cameras,
> > and with big separation:
> >
> > http://www.freeimagehosting.net/image.php?3f93db70f8.jpg
>
> That's not for stereo, but for accurately measuring distances through triangulation. Note that *your* eyes are arranged in a horizontal configuration.
>


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Re: Stereo distortions in stereo panoramas

Aldo Hoeben
> Yes, but why is so important the orientation of the camera?, you
> can rotate your head 90 degrees and still viewing in 3D.

If that is how you want to view your images, then by all means arrange your cameras in a vertical orientation instead of horizontal. But it sounds mighty uncomfortable to me ;-)

Earthmine uses the two cameras to be able extract actual 3d geometry from the pair of images. To do this with accuracy, the requirement is to know the exact distance between the two cameras, but it is not all that important how the cameras are arranged. If however they would put the cameras side-to-side, one camera would obscure part of the view of the other camera and vice versa. Ofcourse this still happens with the vertical arrangement, but for this application the zenith and nadir are not that interesting.

Stereo capture and viewing is something altogether different. For that the cameras need to mimick what the eyes do. IE: the two cameras (arranged horizontally) would need to rotate around a single shared point. If you were to use two one-shot systems, you would have the aforementioned problem that the two cameras see eachother when looking to the sides (left camera sees the right camera when looking right). Additionally things will get screwy if you look backwards in the panorama; the left and right "eye" will be swapped. Two one-shots are just not going to work.

Having said all that, if earthmine would indeed create accurate 3d geometry from their capture, it would be possible - in theory - to create stereo pairs out of that. But that requires A LOT of processing, and even then the result would be a far cry from what Peter has achieved lately with his stereo spinner work.

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Re: Stereo distortions in stereo panoramas

enridp
Yes you are right, If we have the cameras in vertical configuration then the red and cyan will be up and down not at the sides, even after rotation of the images.
(an easy test, rotate your head with any Stereo Image and you can see how the effect is lost)

And the Stereo images from images with 3D information (distance of each pixel) could work, but the effect will not "volumetric" I think.
I mean, we will see different planes at different distances, not objects with volume.
That's what happens with "Fake3D" movies:
http://realorfake3d.com/


--- In [hidden email], "Aldo Hoeben" <aldo@...> wrote:

>
> > Yes, but why is so important the orientation of the camera?, you
> > can rotate your head 90 degrees and still viewing in 3D.
>
> If that is how you want to view your images, then by all means arrange your cameras in a vertical orientation instead of horizontal. But it sounds mighty uncomfortable to me ;-)
>
> Earthmine uses the two cameras to be able extract actual 3d geometry from the pair of images. To do this with accuracy, the requirement is to know the exact distance between the two cameras, but it is not all that important how the cameras are arranged. If however they would put the cameras side-to-side, one camera would obscure part of the view of the other camera and vice versa. Ofcourse this still happens with the vertical arrangement, but for this application the zenith and nadir are not that interesting.
>
> Stereo capture and viewing is something altogether different. For that the cameras need to mimick what the eyes do. IE: the two cameras (arranged horizontally) would need to rotate around a single shared point. If you were to use two one-shot systems, you would have the aforementioned problem that the two cameras see eachother when looking to the sides (left camera sees the right camera when looking right). Additionally things will get screwy if you look backwards in the panorama; the left and right "eye" will be swapped. Two one-shots are just not going to work.
>
> Having said all that, if earthmine would indeed create accurate 3d geometry from their capture, it would be possible - in theory - to create stereo pairs out of that. But that requires A LOT of processing, and even then the result would be a far cry from what Peter has achieved lately with his stereo spinner work.
>


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