Fast form measurements using a digital micro-mirror device in imaging with partially coherent illumination

Abstract

We present a new technique for fast form measurement based on imaging with partially coherent illumination. It consists of a 4 f-imaging system with a digital micro-mirror device (DMD) located in the Fourier plane of its two lenses. The setup benefits from spatially partially coherent illumination that allows for depth discrimination and a DMD that enables a fast depth scan. Evaluating the intensity contrast, the 3D form of an object is reconstructed. We show that the technique additionally offers extended depth of focus imaging in microscopy and short measurement times of less than a second.