METROLOGICAL APPARATUS AND A METHOD OF DETERMINING A SURFACE CHARACTERISTIC OR CHARACTERISTICS

摘要

A metrological apparatus includes an optical measurement system (1) such as a coherence scanning interferometer operable to obtain measurement data representative of a surface of a workpiece and a rotation device (15) to effect relative rotation between the optical measurement system and the workpiece about a measurement axis to enable a plurality of measurement data sets to be obtained with each measurement data set being obtained by the optical measurement system at a respective one of a number of different relative rotational orientation s of the optical measurement system and the workpiece. A data corrector (323) is provided to obtain correction data to enable correction of a measurement data set. The correction data may be an average of the plurality of measurement data sets.

主权项

1. A metrological apparatus for determining a surface characteristic of a surface of a workpiece, the metrological apparatus comprising:
an optical measurement system to obtain measurement data representative of a surface of a workpiece; a rotation device to effect relative rotation between the optical measurement system and the workpiece about a measurement axis to enable a plurality of measurement data sets to be obtained with each measurement data set being obtained by the optical measurement system at a respective one of a number of different relative rotational orientations of the optical measurement system and the workpiece; a correction data obtainer to use the plurality of measurement data sets to obtain correction data to enable correction of a measurement data set.