OmniSDF: Scene Reconstruction using Omnidirectional Signed Distance Functions and Adaptive Binoctrees

We present a method to reconstruct indoor and outdoor static scene geometry and appearance from an omnidirectional video moving in a small circular sweep. This setting is challenging because of the small baseline and large depth ranges. These create large variance in the estimation of ray crossings, and make optimization of the surface geometry challenging. To better constrain the optimization, we estimate the geometry as a signed distance field within a spherical binoctree data structure, and use a complementary efficient tree traversal strategy based on breadth-first search for sampling. Unlike regular grids or trees, the shape of this structure well-matches the input camera setting, creating a better trade-off in the memory-quality-compute space. Further, from an initial dense depth estimate, the binoctree is adaptively subdivided throughout optimization. This is different from previous methods that may use a fixed depth, leaving the scene undersampled. In comparisons with three current methods (one neural optimization and two non-neural), our method shows decreased geometry error on average, especially in a detailed scene, while requiring orders of magnitude fewer cells than naive grids for the same minimum voxel size.