Abstract: A method for recovering missing spectral amplitude and phase information of an input real, positive valued image or signal possibly carried by incoherent or coherent waves.

Abstract: A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks and using a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. Adding a reference wave to the iterative process provides better phase recovery systems and aid in the preventing of phase wrapping. The reference wave is added on-axis to provide a well-controlled amplitude. The reference wave is added after the physical or digital transformation system and subtracted before recording the initial amplitude.

Abstract: Embodiments include methods and systems for improving information security of an input signal. Embodiments include encrypting the input signal, based on concurrently executing a plurality of sequences of transformations of the input signal. Embodiments include, for each sequence of the plurality of sequences: performing a discrete Fourier transform on the input signal; preserving amplitude information of the input signal; and ciphering the input signal based on a unique key that corresponds to the sequence. In embodiments, executing each one of the sequences produces a corresponding encrypted data signal. In embodiments, recreation of the input signal requires each of the encrypted data signals and the corresponding unique key.

Abstract: A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks and using a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. Adding a reference wave to the iterative process provides better phase recovery systems and aid in the preventing of phase wrapping. The reference wave is added on-axis to provide a well-controlled amplitude. The reference wave is added after the physical or digital transformation system and subtracted before recording the initial amplitude. An additional camera at the input plane records the amplitudes of the original input wave which are used during the iterative process.

Abstract: A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks, without a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. The special masking system is (1) a unity mask together with one or more bipolar binary masks with elements equal to 1 and ?1, or (2) a unity mask together with one or more phase masks, or (3) a unity mask together with one pair of masks or more than one pair of masks having binary amplitudes of 0's and 1's, in which the masks in the pair are complementary to each other with respect to amplitude, or (4) one or more pairs of complementary masks with binary amplitudes of 0's and 1's without a unity mask.