Motion compensation for interferometric off-center measurements of rotating objects with varying radii

Interferometric 3D metrology on arbitrarily moving objects is possible if the reference phase is adapted to match the object speed. We show this theoretically for rotation with constant angular velocity and provide experimental results for off-center measurements of rotating objects with varying radii. We describe the nonintuitive property that the phase compensation speed does not depend on the radius of the object under test, which is useful for the deployment of this physical measurement technique. We apply the findings to multiwavelength holography and demonstrate height measurements on a gear rotating at 2°/s.