Figure 4: Overlay scatterplots to compare pairs of scanners. They are the following in line sequential order: A to B, A to C, A to D1200, A to D600, B to C, B to D1200, B to D600, C to D1200, C to D600, D1200 to D600. Scan pairs are shown on the right. x axis: MTR values for scan 1; y axis: MTR values for scan 2 (in the pair).