Text information security protection method based on computer-generated holograms

Currently, computer-generated holograms (CGHs) based on ray tracing technology are generated faster and faster, and the reconstructed scenes are getting bigger and bigger and contain more and more information. Based on this situation, there are also more applications of using CGHs to hide information, but there is a lack of research on the ability to hide information. To address this issue, this paper proposes a point-sampling CGH method based on ray tracing. Our method utilizes ray tracing techniques to rapidly sample text information at different depths in the scene and hides the depth-encoded text information in the carrier image using discrete cosine transform. The reconstructed image after embedding shows good results, with a peak signal-to-noise ratio (PSNR) of 29.56 dB between the hidden images before and after embedding. The PSNR value between the embedded carrier image and the original carrier image is 51.66 dB, making it difficult for the human eye to distinguish, thereby effectively protecting the generated CGH. We also analyzed the maximum information density and observed that computational holograms obtain the maximum information density at 200×200 resolution.