An evaluation system (10) for evaluating media is described. The system is particularly suitable for evaluating banknotes to determine their suitability for use in an ATM. The system comprises sensing means (12) for sensing properties of media (18) including the location of any imperfection in the media, and an evaluation module (16) for evaluating imperfections in the media(18). The evaluation module (16) includes a classifier (52) comprising an artificial neural network (60) and fuzzy logic (66). The evaluation module (16) may include a plurality of classifiers (52), and a second level classifier (56) for generating a suitability index (20) from the outputs of the first level classifiers (52). A method of evaluating media is also described.