Double-digital fringe projection for optical phase retrieval of a single frame

Digital Fringe projection profilometry is widely used to measure the 3D surface shape of an object. In industrial applications, where dynamic situations are presented, single frame analysis techniques are suitable to work better and are desirable over other optical techniques due to the fast acquisition of data, the few elements needed to build an experimental set-up and the non-synchronization between all components required to do the measurement. In this paper we propose a method based on a double-digital fringe projection that only requires one fringe pattern for the extraction of the optical phase by means of the Isotropic Quadrature Transform. The method is very simple, fast, low cost and easy to implement for engineering purposes. The double-digital fringe projection allows the camera of the set-up to record the shadows corresponding to the shape of the object, giving the chance to get a good quality measurement considering details of the object that cannot be detected with other kind of illumination or other optical techniques. A few experiments are presented and the resulted retrieval phase of different objects is shown together with a profile of the phase across the y-axis in a selected point along the x-axis.