where kx and ky are two components of the wave vector, and AR is the amplitude of thereference wave.The intensity of the amplitude image can be computed byThe phase contrast image is obtained by the argument ofThe phase contrast image from the numerical reconstruction of the hologram, as shown inFig. 2(f), can be used to calculate morphological properties such as thickness, surface area,and volume of samples such as red blood cells.Figure 3 shows the schematics for encrypting and storing n digital holograms, which is based on DRPE and phase encoding multiplexing. In Fig. 3, the two-dimensional digital holograms are obtained by spatially filtering holograms from the DH, for example, Fig. 2(d).The digital holograms are phase modulated by the RPM1s, which are placed at the input plane and expressed by exp[jφ1(x, y)]. x and y are space coordinates of a given pixel in the RPM1.The digital hologram is then Fourier transformed, which is expressed aswhere ξ and η are coordinates of a given pixel in the Fourier-transformed image and Oi (x, y) is the amplitude information of the (x, y)th pixel in the ith hologram. φi1 (x, y) is the random phase of the (x, y)th pixel in the RPM1 applied to the ith hologram, which is in the range of –π to π.