Dynamic visual cryptography for optical control of vibration generation equipment

An optical experimental technique based on dynamic visual cryptography is proposed for the optical control of vibration generation equipment. A secret image is embedded into a stochastic background using initial stochastic phase deflection and phase matching algorithms. The embedded image can be interpreted by a naked eye when the structure vibrates in the pre-determined regime; the decoding of the image is based on the formation of moiré fringes in the time-averaged image. A simple visual inspection is enough to determine if the amplitude of vibrations is kept in the tolerated range. The sensitivity of the proposed optical control method as well as the applicability of this method for different types of oscillations is discussed.

► Dynamic visual cryptography is exploited for the optical control of vibration generation equipment. ► Decoding of the secret image is based on time-averaged moiré fringes. ► The proposed technique can be used for the optical control of complex nonharmonic oscillations.