Projection Moire Research Articles

Projection moire with moving gratings for automated 3-D topography

A method is presented that permits a vast increase in the capability of projection moire topography. It involves simultaneous translation of the reference and object gratings to generate high-definition contour fringes without any of the artifacts associated with ordinary moire. Experimental results are presented for single- and double-projection arrangements for a general 3-D object and an inclined-plane test surface. Clear contouring fringes for angles of inclination up to 80° are shown, and fringe densities higher than the grating frequency are obtained. Coupled with the flexibility of projection moire, this technique is shown to be particularly suited for computer-assisted moire fringe pattern analysis. Means of practical implementation in on-line processing system are proposed.

Shadow And Projection Moire Techniques For Absolute Or Relative Mapping Of Surface Shapes

Optical methods of shadow and projection moire are particularly suitable for mapping the absolute shape of a given surface or the difference between that surface and a master one or its accidental shape change. Essentially, product moire fringes are obtained on an image plane where a filter grating analyzes the image of the test surface which has been coded by projecting a master grating on it. The article resumes the theory in a unifying approach and presents a comprehensive list of applications.