Fig. 2.

Demonstration of the updating method of the scale factor µ. One possible method is to update µ according to the Euclidean distances between p_i, q_i and o, which works for p₁ and q₁ because they have close depthes as o. However, this method may result in slow µ updating rate for p₂ and q₂ because $\Vert {\mathbf{q}}_2-\mathbf{o}\Vert \approx \Vert {\mathbf{p}}_2-\mathbf{o}\Vert$. Hence, it is more efficient to compare v_i and x_i to move points p_i to the related lines of sight.