Figure 2.

(a) A sketch of two tensors and their spatial relationship in the x′, y′, z′ coordinate system to produce the vote V(u, v, w) in Equation 2: briefly speaking, the vote from a tensor at (x, y, z) to another tensor at (u, v, w) with tangent t depends only on their relative distance l and angle θ (see text for full description). (b) The figure depicts the tensor voting stick field with tensors shown along their tangential direction: since the votes are computed solely from the relative position of neighboring tensors, a voting field can be pre-computed.