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cheerioboy
Up and Coming
January 29, 2014

VR Player & 3d generated stereo images

question - Is there a correct barrel distortion factor for computer generated 3d panos? Is it possible to get lines perfectly vertical or will there also ways some warping in the peripheral view? Is there a recommended FOV?

I've been playing with sliding the FOV with the mouse wheel, and dialing the barrel distortion to a point where vertical lines line up within the Oculus. But I feel like the sense of depth flattens and I go cross eyes by the time the edges straighten. So I've loosened it up a bit for the moment to make viewing more relaxed.

Anyone else played around with this - are there exact numbers that are recommended or is it dependent on the particular image being viewed? I hope to have some test images at some point to share as I deal with this process.

thanks

    3 replies

    j1vvy
    Up and Coming
    January 29, 2014
    The barrel distortion is to correct for the lenses in the Rift it does not matter what image you are looking at.
    The amount of distortion needed will differ with cups used and how close the rift is to your eye.
    Open one of the test images with grids or lines.
    Adjust the barrel distortion until you always see the lines as straight.

    For the 3D images created from many cameras I expect some differences in the nadir of your checker board. These should diminish if you can use even more images. A camera every column of pixels would be ideal.
    cheerioboyAuthor
    Up and Coming
    January 29, 2014
    @ j1vvy

    I think the barrel distortion became more prominent for me when I started to widen the eye distance. So I might settle on keeping it realistic (2.5 - 3.5 inches?). Originally I wanted to push the distance to push the depth perception but it seems to be causing issue with straightening edges when compensating the distortion.

    As for the nadir:

    I'm currently settling on HD resolution for viewing with the Oculus Dev kit:

    HD 1080, 2160x1080 (1920x1080)
    - Spherical camera, fov 1
    - Output Size, Width: 6, Height: 1080

    To get to every capture being a pixel wide, what would I do? VRay does allow me to go below 1 fov.
    .5 fov, double the steps to 720, and drop the pixel width to 3? Might not be worth it at that point... ha
    .25 fov
    .1 fov!
    j1vvy
    Up and Coming
    January 30, 2014
    This explains barrel distortion http://www.youtube.com/watch?v=B7qrgrrHry0

    If you are going to generate 2160X1080 panos then each column would cover
    360/2160 = 1/6 = 1.6666666666 deg
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