Figure 2 shows a segment of a circular pipe with r as its radius and (0,0,0) and (0, 0, 1) as the two ends of its centre-line segment. A point cloud (white dots) is captured along the pipe surface with their coordinates represented as {(x, y,, Z;), i=1, 2, ... n}. What is the error of measurement for the entire point cloud in the pipe surface? (X, Y, Z) (0,0,1) r (0, 0, 0) Figure 2: A segment of a circular pipe