US Patent 7607528 Method and device for checking banknotes

A method and an apparatus for checking bank notes, in which data from at least two different measurings of the bank notes to be checked are evaluated. Bank notes are checked, whereby data from at least two different measurings of bank notes to be checked are evaluated, a first property of the bank note to be checked being derived from the data of at least one first measuring, at least one second property of the bank note to be checked being derived from the data of at least one second measuring. A correlation between the first and the second property for the same places on the bank note to be checked is determined, and the first property is derived once again. For the places of the bank note to be checked, for which a correlation between first and at least second property has been determined, an altered derivation of the first property from the data of the at least first measuring is performed.