Técnicas ópticas para el contorneo de superficies tridimensionales

Abstract

We will present some non-contact systems for obtaining three-dimensional objects topography. The described systems are incoherent fringe projection technique, Talbot and speckle interferometry. In fringe projection technique, the digitalization is realized when black and white lines are projected over the object and this image is captured by the CCD. In Talbot interferometry, the object is collocated on one of the grating auto-image planes. The deformed grating image is captured by the CCD and superposed with a synthetic grating generated in the computer for obtaining a moiré pattern which gives information about the object topography. In the speckle interferometry technique, dual collimated illumination is used for contouring. The collimated beams illuminate symmetrically the object at an angle $\theta $ with the optical axis, and an image is recorded in the usual way. Now if the object is tilted by a small $\Delta \theta $, a system of equispaced interference planes intersects the object. A second recorded is taking in this object position. Both images are processed to get the object topography. The shape of the car part, a gasket, shoe mold and other examples of digitalized objects are shown. Advantages and disadvantages of the techniques are discussed.