Fig. 13From: Round robin comparison study on the form measurement of optical freeform surfacesBilateral difference plots for the concave toroidal specimen: The difference plots between the following four measurements are shown: 1: Mahr TWI, 2: Mahr MFU, 3: IPP MFU, 4: NMIJ UA3P. The plot of row i, column j shows the processed measurement i minus the processed measurement j (pointwise)Back to article page