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darren
Up and Coming
June 17, 2013

One camera versus two cameras question

Some people are claiming to me that you can take 1 camera image, shift it left a little bit and display it to the left eye, and shift the same image right a little but and display it to the right eye, and you will get 3D.

This would mean that you could really just render something once...

Does anyone know the visual implications of this? Does it produce a flat or annoying 3D?

If that's the case, then does it mean the optimal 3D is of two cameras perceiving a scene at slightly different angles? However if you are to focus at infinity it would seem your cameras have to be parallel. Anyone know how rendering from 2 parallel cameras is not like shifting the image left or right?

    2 replies

    geekmaster
    Up and Coming
    June 17, 2013
    "darren" wrote:
    Some people are claiming to me that you can take 1 camera image, shift it left a little bit and display it to the left eye, and shift the same image right a little but and display it to the right eye, and you will get 3D. ... Does anyone know the visual implications of this? Does it produce a flat or annoying 3D? ... Anyone know how rendering from 2 parallel cameras is not like shifting the image left or right?

    You will get full immersion, and in fact almost all 360-degree videos are in this format.

    However, it is not true stereoscopic 3-D. This only matters for nearby content. For first-person exploration of expansive landscapes, you will not notice the difference most of the time.

    Two parallel cameras also shift the parallax (horizontal offset based on object distance from cameras), while shifting the monoscopic image pair does not.

    Here is a thread about camera distance and stereoscopic parallax:
    viewtopic.php?f=33&t=551
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    darrenAuthor
    Up and Coming
    June 18, 2013
    "geekmaster" wrote:
    "darren" wrote:
    Some people are claiming to me that you can take 1 camera image, shift it left a little bit and display it to the left eye, and shift the same image right a little but and display it to the right eye, and you will get 3D. ... Does anyone know the visual implications of this? Does it produce a flat or annoying 3D? ... Anyone know how rendering from 2 parallel cameras is not like shifting the image left or right?

    You will get full immersion, and in fact almost all 360-degree videos are in this format.

    However, it is not true stereoscopic 3-D. This only matters for nearby content. For first-person exploration of expansive landscapes, you will not notice the difference most of the time.

    Two parallel cameras also shift the parallax (horizontal offset based on object distance from cameras), while shifting the monoscopic image pair does not.

    Here is a thread about camera distance and stereoscopic parallax:
    viewtopic.php?f=33&t=551


    That's right. I can clearly envision that. And that's why a dual-camera setup is important, as I believed... And... As you said, if the majority of the scene is far away, you can probably get away with 1 camera, and that makes sense. So... Well, I suppose there's an optimization that could render far away things once, and nearby things multiple times, but anyway... You need dual cameras for nearby objects, and that might be why we're all not cyclops.

    Thanks for your input.
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