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Figure 24.( A, B, E, F) Roughness of FS freeform lenses given as areal measurement maps for ground surfaces;( C, D, G, H) corresponding measurements at the same positions after PJP( position P and V according to Fig. 21( A)).
4.3.2 Waviness and roughness
Figure 22 compares the averaged waviness and roughness measured at the two positions, designated as“ P” and“ V”, as shown in Figure 21( A), after grinding and after PJP, respectively. The error bars in Figure 22 indicate the range of deviations between the two measurement positions. Due to the geometry-related surface curvatures, comparable roughness measurements could only be carried out at the two positions exhibiting near-zero slope. Otherwise, significant measurement artifacts showing interference fringes are visible, which deteriorate the measurement and make it unusable. Despite all three samples are ground with the