3-D reconstruction of real-world objects using extended voxels

In this paper we present a voxel-based 3-D reconstruction technique that computes a set of non-transparent object surface voxels from a given set of calibrated camera views. We show that the quality of the reconstruction strongly depends on the accuracy of the computed voxel projection in the image plane and discuss different approximations of the exact projection. The most simple and computationally least demanding approximation is obtained when projecting point voxels, i.e., voxels without spatial extent. However, correct occlusion handling is not possible for point voxel volumes leading to reconstruction artifacts. The most accurate projection is obtained by computing the exact outline of the projected voxels. This projection is computationally most demanding but allows correct occlusion handling during reconstruction. Experimental results that compare the reconstruction quality for point and exact voxel projection show that it is worthwhile computing the exact image plane footprint of the projected voxels.