A method is described for checking a value document, wherein measuring values of the value document are detected in spatially resolved fashion. The measuring value detected in the respective measuring point is allocated to a node corresponding to this measuring point, and a two-dimensional network of nodes is formed therefrom. A network is formed from the two-dimensional network of the nodes and a source node and a sink node. By means of the maximally possible flow through the network, the value document is classified as suspected of forgery or not suspected of forgery. The maximally possible flow through the network is a measure for the degree of probability of the value document having a continuous object along a direction transverse to the direction of the network, said object indicating a manipulation of the value document, such as e.g. an adhesive strip or a separating line of a composed forgery.

An automatic calibration apparatus and method are disclosed. The automatic calibration apparatus includes a transmitter configured to output a transmission signal, a receiver configured to receive the signal output from the transmitter, and a controller configured to generate the transmission signal at a predetermined frequency to be output by the transmitter, and calibrate the transmission signal by analyzing a signal received by the receiver before banknote identification.

An automatic calibration apparatus and method are disclosed. The automatic calibration apparatus includes a transmitter configured to output a transmission signal, a receiver configured to receive the signal output from the transmitter, and a controller configured to generate the transmission signal at a predetermined frequency to be output by the transmitter, and calibrate the transmission signal by analyzing a signal received by the receiver before banknote identification.

Systems and methods for detecting a document attribute using acoustics are provided. In one embodiment, a method for detecting a feature of a document using acoustics includes emitting a first acoustic signal from a first acoustic transmitter to a first acoustic receiver while a document is between the first acoustic transmitter and the first acoustic receiver, and emitting a second acoustic signal from a second acoustic transmitter to a second acoustic receiver while the document is between the second acoustic transmitter and the second acoustic receiver. The second acoustic signal differs from the first acoustic signal. The method also includes determining the presence of a feature of the document using at least one of the first acoustic signal or the second acoustic signal.

Systems and methods for detecting a document attribute using acoustics are provided. In one embodiment, a method for detecting a feature of a document using acoustics includes emitting a first acoustic signal from a first acoustic transmitter to a first acoustic receiver while a document is between the first acoustic transmitter and the first acoustic receiver, and emitting a second acoustic signal from a second acoustic transmitter to a second acoustic receiver while the document is between the second acoustic transmitter and the second acoustic receiver. The second acoustic signal differs from the first acoustic signal. The method also includes determining the presence of a feature of the document using at least one of the first acoustic signal or the second acoustic signal.

A paper sheet handling apparatus includes: a conveyance path on which a bundle of paper sheets is conveyed; and a detector including a plurality of ultrasonic wave sensors, which is arranged on the conveyance path, and detecting presence or absence of a foreign substance, which is mixed in the bundle of paper sheets by the plurality of ultrasonic wave sensors. The detector causes the plurality of ultrasonic wave sensors to respectively irradiate, with ultrasonic waves, a plurality of positions on a paper surface of the bundle of paper sheets, which is conveyed along the conveyance path, and detects the presence or absence of the foreign substance based on reflected waves of the ultrasonic waves from the plurality of positions.

A paper sheet handling apparatus includes: a conveyance path on which a bundle of paper sheets is conveyed; and a detector including a plurality of ultrasonic wave sensors, which is arranged on the conveyance path, and detecting presence or absence of a foreign substance, which is mixed in the bundle of paper sheets by the plurality of ultrasonic wave sensors. The detector causes the plurality of ultrasonic wave sensors to respectively irradiate, with ultrasonic waves, a plurality of positions on a paper surface of the bundle of paper sheets, which is conveyed along the conveyance path, and detects the presence or absence of the foreign substance based on reflected waves of the ultrasonic waves from the plurality of positions.