Copy-proof machine-readable holograms for security application

The most frequently used optical security features to protect documents and goods against counterfeiting are various types of rainbow holograms and diffractive optical variable devices (OVDs). Although these features offer a fair degree of security and most known falsifications are rather crude imitations it is still possible to copy them with all hidden and visible information. In our opinion it would be helpful to have copy proof holograms containing a machine readable feature to achieve a doubtfree verification at point of sale and other sites. We present our work towards the development of a copy proof and machine readable hologram with an optically encoded security feature.