Apparatus for validating currency items, and method of configuring such apparatus

摘要

A currency validator processes sensor measurements by transforming them using a linear function so that, following calibration, the measurements of an article resemble standard measurements. The acceptance criteria are gradually modified by a self-tuning operation. The validator can be reconfigured to permit it to recognise a new class of articles by (a) deriving a standard set of acceptance criteria for the new class, and (b) altering the acceptance criteria to an extent determined by the extent to which acceptance criteria for a further class differ from standard acceptance criteria for that class, due to self-tuning. <IMAGE>