Contouring Method by Moiré Holography

The holographic interferometry method is applied to the moiré method of the grid projection type, and contouring fringes on stationary objects are obtained experimentally. The regular grid is made by displacing the plate slightly sideways in its plane between the two exposures of double exposure holography. On the other hand, fringes are projected on the object by displacing the point source of object illuminating light. As these fringes are deformed by the relief of the object, the contouring fringes of the object can be found when they are combined with the regular grid. In this method, only the contouring fringes of the object are observed and the regular grid is not seen at all; the object therefore is seen brighter than the one observed through the regular grid. This method should be called the moiré holography in the true sense of the word.