DISTORTION EVALUATING APPARATUS AND DISTORTION EVALUATING METHOD

摘要

Provided is a distortion evaluating apparatus which can quantitatively evaluate distortion of a plane to be measured. The distortion evaluating apparatus (40) evaluates distortion based on three-dimensional measurement data of the plane to be measured. The distortion evaluating apparatus is provided with a quadratic differential means (41) which performs quadratic differential to two-dimensional measurement data of a cross section, which indicates unevenness of the plane to be measured, and derives curvature data of the cross section; an acceptable range setting means (43) for setting a set acceptable range relating to the curvature data, depending on ranges from a reference value to an upper limit value and to a lower limit value; and a distortion data extracting means (42) for extracting data exceeding the set allowable range from the curvature data as distortion data indicating distortion on the cross section.