Roberts, Jonathan (2017) Optical Reading of a Security Element. GB2548493 (B) GB2548493 (A).
Full text not available from this repository.Abstract
A method of determining a unique identifier for a security element 20 comprises: optically reading the security element via a configurable optical filter system 26, wherein an optical property of the filter system varies with respect to its configuration (see Figure 3); the reading further comprising determining data indicative of an optical property of the security element at first and second configurations of the filter system; wherein the unique identifier is determined from a map of the variation in determined data indicative of the optical property with respect to the configuration of the filter system. The reading is undertaken for multiple locations across the security element at each configuration of the filter system, such that the map shows the variation in determined data indicative of the optical property across the security element with respect to the configuration of the filter system. The reading for multiple locations is undertaken in a single step, using a reader with a two-dimensional sensor.