Equirectangular to normal perspective?

[olishea]

Hi guys,

I'm a newbie so please don't bite my head off. 

I've successfully made a a few HDR equirectangular spherical panoramas. Used nIkon D7000 and 10.5mm fisheye. Results are great. 

My question is...can I remove the distortion from an equirectangular so it just looks like a normal perspective image? I want two versions you see, the equirectangular and a background/billboard image that doesn't have the spherical mapping. I would rather just change the panorama rather than start with all my bracketed source images again. 

This is for 3D architectural/product visualisation (IBL)

Cheers and help would be much appreciated. 

Oliver

[Erik Krause]

Am 22.09.2012 15:25, schrieb olishea:
> My question is...can I remove the distortion from an equirectangular so
> it just looks like a normal perspective image? I want two versions you
> see, the equirectangular and a background/billboard image that doesn't
> have the spherical mapping.

An equirectangular covers 360� around. There is no way to have this
undistorted in a flat image. But of course you can extract any
rectilinear image from a sphere.

> I would rather just change the panorama
> rather than start with all my bracketed source images again.

You'd need to switch PTGui to advanced interface: Load your equirect
image, on Lens Settings tab select Equirectangular panorama and set 360�
Field of view. Open pano editor, switch to rectilinear projection and
adjust FoV with the sliders. You can move the panorama around with the
mouse until you get the desired view (don't bother it looks a bit
blurry). Once you're done go to Create panorama tab, choose Maximum Size
from "Set optimium size", give a new name and create.

Depending from the subject you can alos try cylindrical or mercator
output projection or experiment with vedutismo and horizontal
compression. This way you might get larger field of view with little
distortion - depending from your subject.

--
Erik Krause
http://www.erik-krause.de

[Ken Warner]

When the verdutismo projection first came available, I didn't think it was very useful or important. I've changed my mind and think it can be very useful as a way to get a great wide angle shot out of a pano.

[olishea]

 

Thanks Erik,

 Sorry if my technical language was not exact. 

Yes rectilinear is exactly what I needed. I just wanted to extract an undistorted image from a HDR equirectangular. So verticals are vertical etc. 

I only needed 100-120 degrees horizontally and it worked just right. 

What is the panini projection equivalent in PTGui?

Thanks so much for your help. 

[olishea]

verdutismo projection also looks interesting

[Erik Krause]

Am 22.09.2012 18:31, schrieb Ken Warner:
> When the verdutismo projection first came available, I didn't think
> it was very useful or important. I've changed my mind and think it
> can be very useful as a way to get a great wide angle shot out of a
> pano.

True. But thinking again Oliver wants to extract the backplate from a
HDR sphere mainly taken for CGI. This would need to be rectilinear.
Great care would be needed to adjust tonemapping / exposure fusion
correctly. Perhaps it would be best to extract an HDR image and simply
choose exposure in photoshop without any tonemapping...

[Ken Warner]

HDR remains mysterious to me. I've pushed it into the "maybe someday" pile.

[Erik Krause]

Am 22.09.2012 18:51, schrieb olishea:
> verdutismo projection also looks interesting

This is the panini equivalent...