Method and opto-electronic system for reading of coded hidden images from security holograms

Abstract

Methods for recording of holograms with an encoded hidden image (security holograms) and a reading-decoding optoelectronic system are presented in this paper. Security holograms are used as means for control of authenticity of the protected objects. Some modifications of the recording schemes with the code mask in the object beam are proposed. The main problem to be solved is connected with the required precision of the hologram positioning in the readout device. The algorithm of reconstruction of the decoded image is proposed in this paper. The main feature of this algorithm is the presence of the optical and electronic decoding. It allows producing of better than previously protected holograms. As an additional measure of protection of the hologram it is proposed to use the predetermined elements of the hidden image for checking of the hologram authenticity.