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bmild / nerf

Code release for NeRF (Neural Radiance Fields)
http://tancik.com/nerf
MIT License
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Why NDC space has degenerate case when capturing 360 degree views #47

Closed zhengqili closed 4 years ago

zhengqili commented 4 years ago

Hi,

I experimented NeRF on 360-degree scenes, and if I use NDC, there are always degenerate cases like the figure shown below. I am wondering why this happens in NDC space. Does NDC only works for half-hemisphere, do you have any intuition or math explanation for this?

playground_360_ndc

Thanks!

bmild commented 4 years ago

NDC only works when the whole scene lies behind a "near" plane perpendicular to the camera axis. So yes, it will only work for a half-hemisphere scene with less than 180 degree field of view, and certainly not for 360 degree scenes.