On Optimal Illumination for DOVID Description Using Photometric Stereo

Diffractive optically variable image devices (DOVIDs) are popular security features used to protect security documents such as banknotes, ID cards, passports, etc. Nevertheless, checking authenticity of these security features on both user as well as forensic level still remains a challenging task, requiring sophisticated hardware tools and expert knowledge. Based on a photometric acquisition setup comprised of 32 illumination sources from different directions and a recently proposed descriptor capturing the illumination dependent behavior, we investigate the information content, illumination pattern shape and clustering properties of the descriptor. We studied shape and discriminative power of reduced illumination configurations for the task of discrimination applied to DOVIDs using a sample of Euro banknotes.