Near-optimal pitch of a moiré grating for image hiding applications in dynamic visual cryptography

Dynamic visual cryptography is based on hiding of a dichotomous secret image in the regular moire grating. One pitch of the moire grating is used to represent the secret image and a slightly different pitch of another moire grating is used to form the background. The secret is decoded in the form of a pattern of a time-averaged moire fringe when the cover image is oscillated according to a predefined law of motion. The security of the encoding and the sharpness of the decoded secret are mostly influenced by the selection of the pitches of moire grating. This paper proposes scheme for the determination of near-optimal pitches of the moire grating for image hiding in dynamic visual cryptography.