Fig. 11
From: Round robin comparison study on the form measurement of optical freeform surfaces
Processed measurements after subtracting the design form and an individual best-fit sphere of each data set for the concave toroidal specimen. The processed measurements were interpolated on a common grid (1000 pixels x 1000 pixels). For the measurement of the UA3P at NMIJ, several data points had to be masked out, since a large deviation from the design was visible in this area which was not present in the other/previous measurements. This deviation from the design may be due to damage to the specimen during transport