Three-dimensional coordinate measurements using a multiple-pinhole interferometer

We propose a method for noncontact measurements of three-dimensional (3D) coordinates based on a Y-typed multiple-pinhole (MP) interferometer and demonstrate its feasibility in experiments. In this method, a Y-typed MP plate is inserted between the target and an image sensor to form a common-path interferometer. The 3D coordinates of the target are found by an effective algorithm using the discrete phase values on the measurement pinholes of the MP plate. These phase values can be directly extracted from a Fourier transform of the recorded intensity pattern without need of any iterative or phase-shifting algorithm. The method could be significant in real-time coordinate measurements and position tracking applications.