This paper discusses methods of coding latent images in protective holograms in order to increase their degree of protection from counterfeiting and to automate the monitoring of their authenticity. It is proposed to use the operation of vector-matrix multiplication as a coding-decoding algorithm, carried out on optical signals by digital multiplication by means of analog convolution. Possible optical layouts for implementing the chosen algorithm are analyzed.
S. B. Odinokov, "Optoelectronic array processor for identifying holograms with encoded latent images," J. Opt. Technol. 73, 449-456 (2006)