Abstract: A camera system (2) for strip-shaped exposure of a bank note (BN) having good optical properties as well as a compact construction has, symmetrically to an optical axis (OA), mirror assemblies (4a, 4b) of elliptical cross section each extending in the direction of the illuminated strip, light sources formed by LED arrays (6a, 6b), an imaging optic in the form of a SELFOC® lens assembly (8), and a photodetector array (12) onto which the illuminated strip of the bank note (BN) is imaged by the SELFOC® lens assembly (8) in a 1:1 ratio.

Abstract: For examining defects in sheet material, in particular bank notes, the sheet material is convexly curved and tested in the area of the convex curvature. A detector is disposed tangentially to an apex line of the convex curvature for detecting elevations on the bank note surface due to bank note defects against a light background. A suitable optic is used to image this silhouette onto the detector. The detector is formed as a pixel array, and the number and height of shaded pixels are assessed as measures of defect density and size and nature of defects.

Abstract: A method is described for testing thin material wherein the material is irradiated with ultrasonic waves at least in certain areas and transmission of the ultrasonic waves through the material is determined and evaluated. The transmission of ultrasonic waves of different frequencies is thereby determined. The differences of the transmission at the different frequencies are then used to determine a criterion for evaluating the quality, in particular the porosity, of the irradiated material. Furthermore, a corresponding test device is described.

Abstract: The apparatus has an imaging device which converts light emitted by an illuminating device into a substantially parallel light pencil which illuminates a line in a line plane parallel to the sheet material and falls in a first illumination plane at a fixed angle of incidence, the first illumination plane forming with the line plane a first illumination angle and intersecting the line plane along the line. Light reflected along the line in a first detection plane at a fixed angle of reflection is imaged onto a detecting device, the detection plane forming with the sheet material a first detection angle and intersecting the line plane along the line. The angle of incidence is selected equal to the angle of reflection, and the first illumination angle equal to the first detection angle.

Abstract: The invention relates to a method for determining structural inhomogeneities in sheet material, in particular due to creases or tears in bank notes.

Abstract: The apparatus has an illuminating device for illuminating sheet material with clocked excitation light. Both during the light phase of clocked excitation light and during the dark phase of clocked excitation light a sensor detects an intensity of the light emitted by the sheet material in each case. In an evaluation device an intensity of fluorescently emitted light and an intensity of phosphorescently emitted light are derived from the intensities detected in the light phase and in the dark phase of clocked excitation light. In order to ensure long preillumination with high intensity, the sensor preferably detects the intensities of emitted light within, and toward the end (in the transport direction) of, the area of the sheet material illuminated by the illuminating device. Additionally the illuminated area of the sheet material is selected to be so great that it is a multiple of the desired resolution.

Abstract: A method for processing sheet material such as bank notes by collecting measuring data from a plurality of sensor units. From the collected measuring data, deriving measuring results. Then mapping such measuring results on classes, combining individual classes into a property of sheet material with different forms, setting up a freely configurable rule matrix by method of which arbitrary but firmly selected combination of different forms of a quantity of properties can be associated with a sort class, deriving the sort class of the sheet material using the rule matrix, assigning the sort class to the sheet material, transporting the sheet material to a destination unit with the reference to the sort class of the sheet material.

Abstract: In an apparatus for testing sheet material, at least one sensor unit is provided with a memory in which data records of a plurality of sheets can be managed. Each data record is provided with areas in which data from at least one other sensor unit can be stored. The sensor unit preferably has a measuring unit and an evaluation unit, the memory of the sensor unit being provided in the evaluation unit.

Abstract: An apparatus for testing sheet material includes an illumination device which illuminates the sheet material continually and in the total spectral region to be tested, and a receiving device having at least two linear parallel CCD arrays. A filter transmitting a certain spectral region is mounted on each CCD array. The individual filters are selected so that at least one transmits in the visible spectral region and one in the invisible spectral region. For detection of the light diffusely reflected or transmitted by the sheet material, the individual CCD arrays produce electric signals from the received light which are then processed in an evaluation device and compared with reference data for testing the sheet material.

Abstract: The apparatus for determining the stiffness of sheet material is provided with mechanical means which periodically touch the sheet material, causing it to vibrate. The sounds produced by the vibration are detected by a detector. From the detected sounds an evaluating device determines the stiffness of the sheet material. The sheet material is held or guided in a transport device such that it can yield to the mechanical action within certain limits in the area of contact without being irreversibly deformed.

Abstract: In an apparatus for testing documents, the optical illuminating unit comprises at least one light guide provided with fluorescent substance for directing at least two light fractions of different wavelengths onto a common area of the document. The light fractions are switched on and off by the time-division multiplex method. Special switching regulators are provided for regulating not only the switch-on and switch-off operation of the illumination sources but also the brightness thereof.

Abstract: The invention relates to an apparatus for dynamically determining the local weight per unit area of sheet-like material, for example, paper, in which the sheet-like material is exposed to sound waves from a sound transmitter. The portion of sound transmitted and/or reflected by the sheet-like material is measured by aid of a receiver and the weight per unit area determined from the measuring signal. In order to avoid disturbances of the measuring signal due to superimposed sound waves and in order to obtain high local resolution even in the case of quickly moving material to be measured, the transmitter, material to be measured and possibly the receiver as well are arranged on a slant relative to each other in such a way that the portions of sound reflected on these elements are faded out of the path of rays between the transmitter and the receiver. Means are additionally provided to prevent the faded out portions of sound from returning to the path of rays between the transmitter and the receiver.