White-light interferometer without mechanical scanning

Abstract

We introduce an optical 3D sensor that can measure the shape of objects with rough surface. The proposed sensor is based on white-light interferometry but it does not require a mechanical movement of the measured object relative to the measuring device. The output of a fiber optical interferometer is used as the light source for the measuring interferometer. The built-in fiber stretcher changes the optical path difference and replaces the mechanical movement. A focus tunable lens is a part of the imaging system. This lens secures that the measured part of the surface is imaged sharply onto the camera during the measurement process.