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1

Monday, September 7th 2009, 10:22am

converting to cube a cylindrical panorama

Hello

I want to convert cylindrical panoramas to cube : it's one single jpg file, but not equirectangular.

Result whith standard cube2equi command is distorted at top and bottom particurlarly, due to the input format.

Is it possible to indicate the fov while converting so the resulting cube isn't distorted or should i modify my input image thru php by adding blank areas to complete the equirectangular source ?

Thanks for advise!

michel

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2

Monday, September 7th 2009, 4:22pm

Hi rebaj83,

Quoted

should i modify my input image thru php by adding blank areas to complete the equirectangular source ?
Cylindrical projection is not equal to an equirectangular projection cropped in his top and bottom area !!!
Adding blank areas to complete your Cylindrical projection only would result in a Cylindrical projection with 2:1 aspect ratio... *unsure*

Look at this links to have an idea about the differences between Cylindrical and Equirectangular projection:
http://wiki.panotools.org/Cylindrical_Projection
http://wiki.panotools.org/Equirectangular_Projection

I do not know about a easy tool like Ktransform to convert from Cylindrical to cube...
I think you have to convert yours Cylindrical panos to Equirectangular and then convert the equirectangular to cube with Ktransform for example.....

A tool like Hugin can do this Cylindrical to Equirectangular conversion easily. *smile*

Hope this can help,
Salut.

3

Monday, September 7th 2009, 6:33pm

I think it depends on the size of your input image.

Blank top and bottom added to my cylindrical images is a trick that works, fortunately :)

michel

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Posts: 1,153

Location: ANDORRA

Occupation: TV

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4

Monday, September 7th 2009, 9:02pm

Hi rebaj83,

Quoted

I think it depends on the size of your input image.
Yes... if you use a small vertical FoV in your Cylindrical pano as input image, the resulting "false Equirectangular" image (adding Blank top and bottom) can be near similar to the same input image converted to "real" Equirectangular... But not equal... If an exact correct projection is not a matter then it's ok. But if you want a correct projection from Cylindrical to cube, using Ktransform to do so, you must convert your Cylindrical pano to Equirectangular.
I suggest you to compare from your Cylindrical pano with Blank top and bottom added and the same Cylindrical pano converted to Equirectangular. You will notice the difference...
Perhaps Klaus can improve his Ktransform tool to make possible a direct convertion from Cylindrical to cube... *rolleyes*

Salut.

5

Monday, September 7th 2009, 9:46pm

You may be right, will check that.

No answer for my other thread... kvmem - fatalerror - kvmem_sys_saveswapdata() failed

maybe you got a clue?

Thanks

michel

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Posts: 1,153

Location: ANDORRA

Occupation: TV

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6

Monday, September 7th 2009, 10:54pm

Hi,

Yes, I saw this other thread... but I have no idea about this issue.... *wacko* Sorry.

Salut.

This post has been edited 1 times, last edit by "michel" (Sep 8th 2009, 12:58am)