Supplement: Efficient Global Point Cloud Alignment using Bayesian Nonparametric Mixtures

1.1. The matrix Ξkk′ In the main text, we are given two unit vectors μ1k and μ2k′ in R. We define Ξkk′ = Ξ(μ1k, μ2k′), where Ξ(u, v) ∈ R4×4 is defined by u (q ◦ v) = qΞ(u, v)q, where u = (ui, uj , uk), v = (vi, vj , vk), and q = (qi, qj , qk, qr). By standard quaternion rotation formula, we have u (q ◦ v) = ui uj uk T 1− 2q j − 2q k 2(qiqj − qkqr) 2(qiqk + qjqr) 2(qiqj + qkqr) 1− 2q i − 2q k 2(qjqk − qiqr) 2(qiqk − qjqr) 2(qjqk + qiqr) 1− 2q i − 2q j vi vj vk 