[3D CV 연구] 3DGS positional gradient in NDC/view space not in world space

3DGS positional gradient는 NDC/view space에서 계산됩니다.

이는 gradient들을 normalize함으로써 모든 gaussian들이 camera/world space에 어디에 위치하든 image에 미치는 영향력을 동등하게 만드는 역할을 합니다.

Intuitively you can think NDC space as a way to normalize the gradients and treat all gaussians equally with respect to the impact they have on the image no matter where they are in camera/world space.

https://github.com/graphdeco-inria/gaussian-splatting/issues/584