For the determining of the authenticity of banknotes in stores, hypermarkets and supermarkets are widely used currency detectors. The use of such equipment enables to provide effective resistance to counterfeiters attempting to sell counterfeit banknotes. Currency detectors are typically divided into two groups. Visual inspection currency detectors allow to see those security features, which are hidden from the naked eye; areas with magnetic properties, microfonts, visible only in the infrared rays or luminescent glow. Visual detectors are divided into by infrared, ultraviolet, and combined, the principle of which has a number of differences. Checking by the infrared currency detector, for example, involves identifying the presence of special indent marks applied with metameric inks. Another kind of currency detectors - automatic detectors, in which bills through the roller mechanism pass a number of sensors carrying out inspection on the basis of a set of features. Checking of the currency in this way is considered to be very reliable, as it allows to exclude the human factor.