3D reconstruction of structures using spherical cameras with small motion

Abstract

In this research, a method for dense 3D reconstruction of structures from small motion of a spherical camera is proposed. Spherical cameras can capture information from all directions enabling measurement of the entire surrounding structure at once. The proposed technique uses two spherical images clicked at slightly displaced positions near the structure, followed by a combination of feature-point matching and dense optical flow. Feature-point matching between two images alone is usually not accurate to give a dense point cloud because of outliers. Moreover, calculation of the epipolar direction with feature point matching is susceptible to noise with small displacements. However, spherical cameras have unique parallax properties allowing use of dense, global information. Taking advantage of this, the global, dense optical flow field is used. The epipolar geometry is densely optimized based on the optical flow field for an accurate 3D reconstruction. A possible use of this research could be to measure large infrastructures (bridges, tunnels, etc.) with minimal robot motion.