Moiré encryption and decryption in Fourier single-pixel imaging

As a novel imaging technology, Fourier single-pixel imaging (FSI) not only facilitates the transmission of image information but also serves as a tool for image encryption and decryption. In this paper, we propose a dual image encryption-decryption approach that combines FSI with the Moiré effect. The feasibility of this strategy is demonstrated through numerical simulations and optical experiments. In this strategy, an image initially encrypted using the Moiré effect is designated as the watermark. The normalized four-step phase-shifting coefficients of the watermark image are subsequently employed as weights to embed it into structured illumination light, introducing a secondary layer of encryption. FSI is then performed using the structured light that contains the concealed encrypted image information, enabling the initial decryption of the image. Finally, the additive Moiré effect is utilized for secondary decryption. This approach harnesses the advantages of both FSI and Moiré effect encryption, offering a promising solution for scenarios where encryption relying solely on the Moiré effect or FSI encounters limitations.