Giesecke & Devrient Gmbh

Giesecke+devrient Currency Technology Gmbh

Helmut Pradel

Dieter Stein

Jurgen Schutzmann

Jürgen Schützmann

David Sacquard

Jürgen Schmützmann

A method for checking of magnetic properties of value documents with the aid of a magnetic sensor comprises a measuring sensor row having a plurality of magneto-sensitive measuring sensor elements, as well as at least one further magneto-sensitive sensor element which is arranged behind the measuring sensor elements and has a greater distance from the transport plane of the value document than the measuring sensor elements. By means of the further sensor elements, correction signals are detected at correction measuring points of the value document, which are disposed on the same measuring line as the measuring points. In order to eliminate the distance dependence of the measuring signals, the respective measuring signal of each measuring point is corrected on the basis of the signal drop which the correction signal ascertained for this measuring point has in comparison to the measuring signal of the respective measuring point.

Magnetic testing of valuable documents

The invention relates to a magnetic sensor which is designed for checking value documents, and to a method for calibrating the magnetic sensor. The magnetic sensor has different calibrating parameters for hard-magnetic and soft-magnetic magnetic regions, with which parameters the magnetic sensor can correct the detected magnetic signals of a value document, in order to compensate the magnetic sensor's measurement deviations in dependence on the type of the respectively detected magnetic region. For calibration, the magnetic sensor detects calibration measurement values of a calibration medium which is transported past the sensor. By means of the calibration measurement values the function of the magnetic sensor is tested. Where applicable, there is effected after the calibration an adjustment of the sensor using the calibration measurement values, upon which adjustment the calibrating parameters for hard-magnetic and/or soft-magnetic magnetic regions are determined from the detected calibration measurement values of the calibration medium.

Calibration of a magnetic sensor

An apparatus for the calibration of a sensor system has at least one sensor and at least one excitation source, a control device for controlling the sensor system, a calibration medium and a drive which moves the calibration medium into an optical path of the sensor system in a calibration mode and moves the calibration medium out of the optical path of the sensor system in an operating mode for the testing of measuring objects. The calibration medium has more than one reference, where the drive moves the calibration medium into the optical path of the sensor system so that one of the references covers a detection area of the sensor system, and the sensor system measures the reference located in the detection area.

Device and method for calibrating a sensor system

The invention relates to an apparatus used in a method for determining the limpness of sheet material, in particular of bank notes, wherein the sheet material is irradiated with sound waves, sound waves emanating from the sheet material are captured and the limpness of the sheet material is determined therefrom. An especially simple and reliable determination of limpness even independent of the degree of soiling of the sheet material can be achieved by measuring both the transmitted and the reflected sound waves and to form a mathematical ratio of the reflected and transmitted sound-waves, in order to determine the limpness.

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Munich, Germany

Helmut Pradel