Scaling And Resolution Of Scenic Holographic Stereograms

Scaling of holographic stereograms in the ratio did' can be accomplished by using a spacing, d, between component photographs and a different spacing, d', between corresponding holograms. Scaling down of scenic holograms is desirable in order to increase visual impression of 3 dimensionality. Up-scaling of stereograms is called for to decrease the perspective of very small objects. Our analysis of resolution and depth of field shows the projector lens diameter to be the crucial factor in down-scaled stereograms, while the camera aperture is crucial in the up-scaled case. In did' scaling of a scene which extends from s1 tow , the optimum projector aperture is given by PA51/(d/e)VII; the component photographs, should be taken with an aperture of Pits10, which may be altered by the root of the scale factor, by [d/d']2,without seriously degrading the scaled-down stereogram's resolution. In the text numerical examples are given to illustrate the wide applicability of ordinary photographic apertures in making these down-scaled stereograms. Both linear and two-dimensional arrays of scaled-down scenic holograms have been made and these are described.