Image hiding based on near-optimal moiré gratings

Image hiding based on time-averaged fringes produced by non-harmonic oscillations and near-optimal moiré gratings is presented in this paper. The secret image is embedded into the background moiré grating. Phase matching and initial stochastic phase scrambling algorithms are used to encrypt the image. The decoding of the image is completely visual. The embedded secret image appears when the encrypted image is oscillated in a predefined direction, according to a predefined law of motion. No secret is leaked when the encrypted image is oscillated harmonically at any amplitude of oscillation. The criterion of the optimality of a moiré grating serves as a fitness function for evolutionary algorithms which are used to identify a near-optimal moiré grating for image hiding applications. Numerical experiments are used to illustrate the functionality of the method.