Optical encoding system using sparse pinhole arrays for optical information processing

Optical security has attracted much attention nowadays, and relevant research has been widely conducted. Although optical encoding and decoding technique can be useful for securing information, its security is still a major concern in practical applications and more effort should be made to enhance system security. Recently, optical information authentication method has been developed and can be considered as a promising strategy to further enhance system security. The optical information authentication approaches are usually established based on optical encoding setups, and decoded images can be effectively verified without plaintext disclosure. It has also been found that high flexibility can be achieved in the optical information authentication system, and various optical imaging setups, such as phase retrieval, digital holography and computer-generated hologram, can be designed and applied in practice. To some extent, a new research perspective has been opened up for optical information security due to the development of optical information authentication strategy. It is expected that more optical information authentication systems can be established in the future. In this paper, one optical information processing method, i.e., for optical image authentication, is presented based on phase-truncated encoding system using sparse pinhole arrays. During optical encoding, phase-truncated strategy is employed, and sparse pinhole arrays are applied in spatial frequency domain and CCD plane, respectively. Since plaintext cannot be clearly observed during the decryption even using correct security keys, optical authentication method is further applied to verify the decrypted image. High security is achieved, and an effective security layer can be established for phase-truncated optical encoding system.