“…The quality of the object reconstruction therefore depends on the choice of the aperture A(x, y) and the decoding function G (Groh etal., 1972;Brown, 1974;Cannon and Fenimore, 1980). When the modulation of the incident fluxes is obtained by means of a coded mask consisting of N elements of equal size and shape, M of which are transparent, the aperture A may be considered as a series of step functions.…”