  Photorealistic reconstruction relying on 3D Gaussian Splatting has shown
promising potential in various domains. However, the current 3D Gaussian
Splatting system only supports radiance field reconstruction using undistorted
perspective images. In this paper, we present OmniGS, a novel omnidirectional
Gaussian splatting system, to take advantage of omnidirectional images for fast
radiance field reconstruction. Specifically, we conduct a theoretical analysis
of spherical camera model derivatives in 3D Gaussian Splatting. According to
the derivatives, we then implement a new GPU-accelerated omnidirectional
rasterizer that directly splats 3D Gaussians onto the equirectangular screen
space for omnidirectional image rendering. We realize differentiable
optimization of the omnidirectional radiance field without the requirement of
cube-map rectification or tangent-plane approximation. Extensive experiments
conducted in egocentric and roaming scenarios demonstrate that our method
achieves state-of-the-art reconstruction quality and high rendering speed using
omnidirectional images. The code will be publicly available.
