Calibration assembly for an inspection system

A method of calibrating an inspection system, comprising:

• rotating a test part to contact a displacement measurement device;
• simultaneously rotating the test part and moving the displacement measurement device to a new position,
• measuring a first displacement at the new position using the displacement measurement device;
• rotating the test part at a pre-determined rotation angle;
• repeating the steps of rotating the test part to contact the displacement measurement device and simultaneously rotating the test part and moving the displacement measurement device to measure a second displacement;
• and
• using the first and second displacements to adjust measurements of the inspection system.

A calibration assembly for an inspection system, comprising:

• a servo motor configured to rotate a test part about a rotary axis at pre-determined rotating steps;
• a slider configured to move the test part along a z-axis;
• a displacement measurement device configured to measure first and second displacements corresponding to the test part at first and second positions of the displacement measurement device;
• a processor configured to estimate calibration parameters from the first and second displacements measured using the displacement measurement device.