Rift lens distortion vs Fisheye lens distortion.

[Diorama]

How much difference is there? In terms of shape and degree of warping, how similar is a consumer fish-eye lens to the pre-distortion required for clean images on the Rift?

The reason I ask is about using 3d fisheye camera sources as an input device for the rift. You could make a 1metre (3 feet) tall top-hat, like a clown, and put the camera in the top. Instant periscope! And of course, many other uses.

Owners of DIY rifts, can you tell me how, say, the following video looks on your setup?
[youtube-hd]http://www.youtube.com/watch?v=alzVuW_3Ab8[/youtube-hd]

Thanks.

If there is a cheap way to get a 3d dual-camera setup with a physical solution to the LEEP style warping in the rift then I think it would open up a world of possibilities.

[geekmaster]

Because image pre-warp is done in software, different displacement maps could be used for different input sources. In addition to fisheye lenses on the input, you could support SBS-Half (which uses horizontally-compressed image pairs). It may be useful to also take output lenses into account during pre-warp, so that the software can work with various DIY Rift (or non Rift) HMD devices.

The pre-warp software should allow you to select (or supply) a pre-warp mask (or procedurally-generated equivalent).

[Diorama]

Because image pre-warp is done in software, different displacement maps could be used for different input sources. In addition to fisheye lenses on the input, you could support SBS-Half (which uses horizontally-compressed image pairs). It may be useful to also take output lenses into account during pre-warp, so that the software can work with various DIY Rift (or non Rift) HMD devices.

The pre-warp software should allow you to select (or supply) a pre-warp mask (or procedurally-generated equivalent).

Thanks geekmaster. I understand that this could be done in software with pre-warp, but I suppose what I'm asking is how hard it would be to find a lens for your camera that pre-warps entirely optically, for zero-latency.

[geekmaster]

Because image pre-warp is done in software, different displacement maps could be used for different input sources. In addition to fisheye lenses on the input, you could support SBS-Half (which uses horizontally-compressed image pairs). It may be useful to also take output lenses into account during pre-warp, so that the software can work with various DIY Rift (or non Rift) HMD devices.

The pre-warp software should allow you to select (or supply) a pre-warp mask (or procedurally-generated equivalent).

Thanks geekmaster. I understand that this could be done in software with pre-warp, but I suppose what I'm asking is how hard it would be to find a lens for your camera that pre-warps entirely optically, for zero-latency.

It depends on how accurate you want your pre-warping to be. Many FPV enthusiasts use wide-angle lenses (as can be seen when watching many of the videos), and they are not "unwarped" for viewing. I think that for the intended purpose of FPV flying, some leftover warp distortion is fine. I also think some residual warp distortion when wearing a Rift HMD will be fine in many ways cases, especially when the most distorted parts of the view are way out in the peripheral vision. Those of us who wear glasses are well accustomed to warp and focal distortion in our peripheral vision, and even a fair degree of chromatic aberation at the outer edges of our lenses. After awhile, we just ignore this and stop noticing it. The same will be true for visual content while wearing the Rift. In fact, in a game, you should EXPECT some distortion and occlusion from the virtual eye wear, Google and helmet worn by your avatar character.

So first just try it without additional warp correction, then fix it later only if required for your application. IMHO.