Superimposed Fringe Projection for 3D Shape Acquisition by Image Analysis

The aim in this work is the development of an image analysis technique for 3D shape acquisition, based on luminous fringe projections. In more detail, the method is based on the simultaneous use of several projectors, which is desirable whenever the surface under inspection has a complex geometry, with undercuts or shadow areas. In these cases, the usual fringe projection technique needs to perform several acquisitions, each time moving the projector or using several projectors alternately. Besides the procedure of fringe projection and phase calculation, an unwrap algorithm has been developed in order to obtaincontinuous phase maps needed in following calculations for shape extraction. With the technique of simultaneous projections, oriented in such a way to cover all of the surface, it is possible to increase the speed of the acquisition process and avoid the postprocessing problems related to the matching of different point clouds.