Image Encryption Based on Interleaved Computer-Generated Holograms

An encryption method based on interleaved computer-generated holograms (CGHs) displayed by a spatial light modulator (SLM) is demonstrated. Arbitrary decrypted complex optical wave fields are reconstructed in the rear focal plane of two phase-only holograms, generated from original image using a vector decomposition algorithm. Two CGHs are encoded into one hologram by interleaving the column of pixels, which optically combines the optical wave fields of two neighboring phase-only modulated pixels. The designed image encryption system may avoid the inherent silhouette problem and alleviate the precise alignment requirements of interference encryption. Video encryption and real-time dynamic decryption is demonstrated using one SLM.