EP2997553A1

EP2997553A1 - Device and method for examining value documents, in particular banknotes, and value document processing system

Info

Publication number: EP2997553A1
Application number: EP14718518.5A
Authority: EP
Inventors: Shanchaun SU; Steffen Schmalz
Original assignee: Giesecke and Devrient GmbH
Current assignee: Giesecke and Devrient Currency Technology GmbH
Priority date: 2013-04-22
Filing date: 2014-04-17
Publication date: 2016-03-23
Anticipated expiration: 2034-04-17
Also published as: US20160063791A1; MX356923B; MX2015014721A; CA2902244A1; WO2014173522A1; AU2014256522B2; US9852568B2; DE102013006925A1; EP2997553B1; CA2902244C; AU2014256522A1

Abstract

The invention relates to a device and to a method for examining value documents (3), in particular banknotes, and to a value document processing system having at least one sensor for detecting an electromagnetic radiation transmitted by a value document (3) and generating corresponding first sensor signals and for detecting an electromagnetic radiation remitted by the value document (3) and producing corresponding second sensor signals and an evaluation device for examining whether the value document (3) has a foreign object (4), in particular an adhesive strip, taking into account first and second sensor signals which correspond to the electromagnetic radiation transmitted or remitted in each case in the region of the edge of the value document (3). The invention prevents deformations (5) in the region of the edge of value documents (3) from being identified as foreign objects (4).

Description

Device and method for checking value documents, in particular banknotes, as well as value document processing system

The invention relates to a device and a method for checking value documents, in particular banknotes, as well as a value-document processing system. In banknote processing systems, characteristics of banknotes, such as banknotes, are determined. Printed image, denomination, authenticity and condition, determined by physical properties of banknotes detected by sensors and the sensor data generated here are evaluated.

When checking the condition, the so-called fitness, of a banknote, it is checked whether it meets certain criteria in order to be able to be put back into circulation or removed from circulation. In addition to the degree of soiling and wear, the presence of undesirable foreign objects, usually in the form of adhesive strips or other stickers, on the banknote represents an important criterion.

The test for the presence of adhesive strips is usually carried out by measuring the thickness of the bill to be tested by means of mechanical or ultrasonic thickness sensors.

From DE 10 2010 021 803 AI is also known to recognize adhesive strip on the basis of a dark field transmission image of the banknote. There, it is exploited that adhesive strips that go beyond the edge of the banknote appear bright in the transmission image due to light scattering on the adhesive strip. If an adhesive strip overlaps the edge of the banknote, the value document edge observed in transmission deviates from the usually straight edge profile. The adhesive tape detection alone On the basis of the transmission image of the banknote, however, it is disadvantageous since it can happen that distortions or deformations of the banknote, which can occur, for example, during machine banknote transport and / or due to a not quite straight cutting edge, are mistaken for adhesive strips, since even with these a bank note edge deviating from the straight edge profile is observed. Such a distorted or deformed banknote is then unnecessarily sorted out due to adhesive tape suspicion and possibly destroyed, although this could have been re-circulated.

It is an object of the present invention to specify a device, a method and a value-document processing system which makes possible the most reliable detection of foreign objects, in particular adhesive strips or other stickers, on the banknote.

This object is achieved by the apparatus, the method and the value-added processing system according to the independent claims.

The device according to the invention for checking documents of value, in particular banknotes, has: at least one sensor for detecting electromagnetic radiation transmitted by a document of value and generation of corresponding first sensor signals and for detecting electromagnetic radiation reflected from the document of value and generation of corresponding second sensor signals and an evaluation device for checking whether the value document has a foreign object, in particular an adhesive strip, taking into account first and second sensor signals which correspond to the respective transmitted or remitted in the region of the edge of the value document electromagnetic radiation. The method according to the invention for checking documents of value, in particular banknotes, comprises the following steps: detecting electromagnetic radiation transmitted by a document of value and generating corresponding first sensor signals, detecting electromagnetic radiation reflected from the document of value and generating corresponding second sensor signals, and checking whether the value document has a foreign object, in particular an adhesive strip, taking into account first and second sensor signals which correspond to the electromagnetic radiation transmitted or remitted respectively in the region of the edge of the value document.

The value-document processing system according to the invention has at least one device for processing, in particular for conveying and / or counting and / or sorting, value documents, in particular banknotes, and is distinguished by the device according to the invention for checking value documents.

The invention is based on the idea of using both the transmission properties and the remission properties in the region of the edge of the value document when checking whether a foreign object, in particular an adhesive strip or another sticker, is present on the value document. In this case, the presence of a foreign object is deduced on the basis of any differences between the edge profile determined from the transmission image and the edge profile of the value document determined from the remission image.

The approach according to the invention is particularly suitable for detecting adhesive strips or other stickers located on documents of value, which be glued to the document of value for repair purposes, for example, to fix defects usually occurring in the edge region of the value document, in particular cracks. In particular, this makes it possible to recognize those adhesive strips which project up to the cut edge of the value document or possibly even slightly beyond it.

As tests have shown, such adhesive objects are recognizable in the region of the edge of the recorded transmission image in the form of an increased brightness relative to the background, whereas the remission image in the corresponding edge region shows no changed brightness curve. This behavior can be explained by the fact that when detecting the transmission image, in particular a dark field transmission image, the light incident on the adhesive object is scattered beyond the cut edge of the value document and is detected during the transmission measurement. As an alternative or in addition to the scattering of the light, it is also possible for the incident light to be conducted from the adhesive object to the cut edge of the adhesive object, where it diffuses out, which, as a result, also results in the emission of light in the corresponding edge region of the value document. In the remission image, however, the adhesive object does not provide increased brightness, so that the actual edge of the respective banknote is observed there.

The approach according to the invention for detecting foreign objects on the document of value is particularly suitable for objects which scatter, break and / or conduct electromagnetic radiation in the visible and / or infrared and / or ultraviolet spectral range. Both clear-looking adhesive strips and adhesive strips that appear dull and almost invisible on the banknote can be recognized. In principle, however, this also applies to the substantially opaque in the visible spectral range Adhesive strips, such as so-called insulating tapes, which can scatter electromagnetic radiation in other spectral ranges, in particular in the ultraviolet and / or infrared spectral range.

The particular advantage of the approach according to the invention of taking into account not only the transmission properties but also the remission properties of the value document along the edge is that the course of the edge in the transmission image changes from the course of the edge in the remission image in the area of one on the value document clearly differentiate the adhesive strip. By contrast, the curves in the transmission and remission image are identical in the case of distortions or deformations occurring at the edge of the value document. Such distortions or deformations of the bill may be e.g. occur during machine banknote transport and / or due to a not quite straight cutting edge. If the deviations from the rectangular shape are not too large, banknotes with such distortions or bulges are not sorted out during the condition check of the banknote.

Banknotes having an adhesive strip are reliably distinguished from banknotes showing only a deformation or bulge by comparing the two margins. This prevents the latter from being incorrectly removed from circulation and, if necessary, destroyed.

The invention thus allows reliable detection of foreign objects, in particular adhesive strips or other stickers, on documents of value. The at least one sensor is preferably designed for spatially resolved detection of the electromagnetic radiation transmitted or remitted by the value document and for generating corresponding first or second sensor signals. In this way, during the check as to whether the value document has an adhesive strip, the spatial progression of both the spatially resolved first sensor signal and the spatially resolved second sensor signal obtained in the region of the edge, in particular along the edge, of the value document can be taken into account, which is a particularly reliable distinction value documents with and without adhesive strips.

In addition, it is particularly preferred that the at least one sensor is designed to generate a transmission image composed of first sensor signals, in particular a dark field transmission image, and a remission image composed of second sensor signals. In a dark field transmission image, the transmission image of the value document is distinguished from a dark image background, whereby, even with low contrasts in the value document, nevertheless well-resolved, high-contrast transmission images are obtained. For this purpose, the value document is subjected to electromagnetic radiation in such a way that direct rays pass the sensor and only those which are deflected in the value document, in particular broken and / or scattered, can reach the sensor. A remission image is a spatially resolved image of the diffuse or directionally reflected electromagnetic radiation from the value document. This embodiment also makes it possible to take into account the spatial progression of the first sensor signal and the second sensor signal obtained in each case in the region of the edge, in particular along the edge, of the value document during the examination of the value document. to ensure a particularly reliable distinction between value documents with and without adhesive strips.

According to a further preferred embodiment of the invention, the evaluation device is designed, in the examination of whether the document of value has a foreign object, in particular an adhesive strip, those first and second sensor signals, respectively, of the respectively transmitted in the region of the edge of the value document or remitted electromagnetic radiation match, compare with each other. If this comparison shows that the first and second sensor signals obtained in the region of the edge, in particular along the edge, of the value document have a substantially identical spatial progression, it can be concluded from this that there is no adhesive strip on the value document. On the other hand, in a section along the edge of the value document, if the spatial profile of the first sensor signals differs from the spatial profile of the second sensor signals, then the presence of an adhesive strip can be deduced therefrom. As a result, documents of value with adhesive strips can be reliably and easily distinguished from those without adhesive strips.

In particular, the positions of the edge points that the transmission image provides are compared with the positions of the corresponding edge points that the remission image provides. And for tape detection, the distance between each edge point of the transmission image and the corresponding edge point of the remission image is determined and evaluated. Normally (without adhesive strips), the two edge courses, which are observed in transmission and in remission, are approximately congruent, ie the corresponding remission and transmission boundary points each have a very small distance from each other. each other, which is below a predetermined distance comparison value. In the case of an adhesive strip, however, these edge courses are not congruent, but rather an increased distance is determined, which exceeds a predetermined distance comparison value, for example over a plurality of adjacent edge point pairs. Since the geometric distortions or bulges of the banknote in the remission image are just as visible as in the transmission image, there is also a very small distance between the remission boundary points and the transmission boundary points, which is below the distance comparison value, even in the case of geometric distortions or rubbing out of the banknote lies. The invention therefore allows a distinction to be made between geometric distortions and strangulation of adhesive strips. This avoids that geometrical distortions or write-offs of the banknote are mistaken for a "false tab" and the banknote in question is unnecessarily sorted out.

In a particularly preferred embodiment of the invention, the evaluation device is designed to determine one or more first edge points based on the first sensor signals, which points correspond to the edge of the value document, and to determine one or more second edge points based on the second sensor signals. which points in the region of the edge of the value document correspond, and at least to compare the position of one of the first edge points with the position of at least one of the second edge points. The first and second edge points, whose positions are compared with each other, are located at the same position of the value document edge, as viewed along the value document root circulating around the value document. Based on the spatial distance between the first and second edge point is checked whether in the area of the edge of the value document, a foreign object, in particular a Adhesive tape, is present. Preferably, for a plurality of pairs of first and second edge points that are adjacent edge point pairs along the edge of the value document, the position of the first edge point and the position of the second edge point corresponding thereto are respectively compared. This adhesive strips can be detected very reliable. In particular, the positions of all first and second edge points obtained along the edge of the value document are compared with each other. Preferably, the evaluation device is designed to determine the first and / or second edge points by comparing the first and second sensor signals with at least one threshold value. Thus, for example, in the transmission image the height of the first sensor signals is compared with a first threshold value, wherein sensor signals which are greater than the first threshold value are assigned to the transmission image of the value document, whereas sensor signals which are smaller than the first threshold value, the background surrounding the value document be assigned. This can then be done by means of edge detection algorithms edge detection, in which a composite of a plurality of first boundary points edge course of the transmission image of the value document is determined. In the remission image, the height of the second sensor signals is compared with a second threshold value; Otherwise, the remarks on the transmission image apply accordingly. By means of threshold value comparison and edge detection, the first and second edge points are determined particularly accurately, which further increases the reliability in adhesive strip recognition.

It is further preferred that the evaluation device is designed to determine at least one distance value, which is a measure of the represents spatial distance of one of the first edge points of one of the second edge points, and in particular to compare the at least one distance value with at least one predetermined distance comparison value.

Moreover, it is preferred that the at least one distance comparison value corresponds to a previously determined distance value based on at least one value document on which there is no foreign object, in particular no adhesive strip. The distance comparison value can be identical for all four edges of the value document, but can also be determined separately for individual edges or each of the edges.

For example, the at least one distance value corresponds to the Euclidean distance between in each case a first and a second edge point. Alternatively, however, it is also possible to use as the distance value, for example, only the difference of that coordinate, e.g. determine the x-coordinate, the first and second edge points perpendicular to the respective edge, i. along the y-direction of the value document.

Alternatively or in addition to the determination of the distance, the size of a surface defined by the boundary points can be determined, which includes the edge profile obtained from the transmission image with the edge profile obtained from the remission image, eg by integration or by up-turning of the respective distance values, and checked whether this exceeds a given area comparison value F. In the case of exceeding the area comparison value, the presence of a foreign object is affirmative, otherwise it is denied. Additionally or alternatively, based on a statistical evaluation of the brightnesses, ie the heights of the first or second sensor signals, statements about the presence of an adhesive strip on the value document can be derived at the first and second edge points. For example, mean values and / or variance values of the brightnesses can be determined.

By one or more of the above-mentioned measures, value documents with and without adhesive strips can be distinguished with particularly high reliability.

The respective first and second edge points, from each of which a distance value is determined, are corresponding points along the value document edge, e.g. Points with the same pixel number, if you go through the remission and the transmission edge course pixel by pixel from the same value document corner. If the transmission image and the remission image are shifted relative to one another, they can be transformed into a common coordinate system such that the four corner points of the transmission image coincide with the four corner points of the remission image, one of the corner points serving as a coordinate origin. A transformation of the transmission resp. Remission image can be done by translation and / or rotation of the respective coordinates. The presence of an adhesive strip on the document of value can thereby be affirmed or excluded with particular certainty.

For example, for several pairs of first and second edge points, which are preferably adjacent edge pairs along the edge of the value document, the distance value is determined in each case and it is checked whether a predetermined minimum number N of (adjacent) pairs of boundary points exceeds the distance comparison value A. In the case where the distance comparison value A is exceeded for at least a predetermined minimum number N (adjacent) pairs of edge points, the existence of a. Foreign object, in particular an adhesive strip, affirmative and otherwise negative.

For example, the evaluation device is designed to determine a number n of distance values which are greater than the distance comparison value, and in particular the check as to whether the value document has a foreign object, in particular an adhesive strip, based on a comparison of the determined number n of distance values are greater than the distance comparison value, with a predetermined number N of distance values. The predetermined number N makes it possible to determine in a simple way in how many, preferably successive, edge points the edge profile of the first and second sensor signals must differ in order to reliably conclude the presence of an adhesive strip.

For example, the minimum number N> 2, preferably N> 4, is. In addition, for the number of edge point pairs which exceed the distance comparison value, an upper limit can be preset, which is chosen as a function of the maximum width of the adhesive objects to be recognized, and the presence of an adhesive strip can only be affirmed if the upper limit is undershot. The distinction between value documents with and without adhesive tape becomes even more reliable.

Further advantages, features and applications of the present invention will become apparent from the following description taken in conjunction with the figures. Show it: FIG. 1 shows an example of a schematic structure of a value document processing system; FIG.

FIG. 2 shows an example of a value document in the form of a banknote; FIG.

FIG. 3 shows an example of a transmission image of that shown in FIG. 2

Banknote;

FIG. 4 shows an example of a remission image of that shown in FIG

Banknote;

5 shows an example of the course of the edge of the transmission image;

6 shows an example of the course of the edge of the remission image;

FIG. 7 shows a superimposition of the courses shown in FIGS. 5 and 6; FIG.

8 shows a first example of the course of first and second

Boundary points of determined distance values; and

9 shows a second example of the course of first and second

Boundary points of determined distance values.

1 shows an example of a schematic structure of a value document processing system 1 with an input tray 2, in which a stack of value documents to be processed, in particular banknotes 3, is provided, and a separator 8, of which the respectively lowest Bank note of the input stack detected and delivered to a - in the selected representation only schematically reproduced - transport device 10, which conveys the bill in the transport direction T to a sensor device 20.

In the illustrated example, the sensor device 20 comprises a first, second and third sensor 21, 22 and 23, which are each preferably designed as a so-called line camera and light emitted from the banknote, in particular in the visible and / or infrared and / or ultraviolet spectral range. detected by arranged along a line sensor elements and converted into corresponding sensor signals.

In the illustrated example, the first and second sensors 21 and 22, respectively, detect from the front and back of the bill remitted, i. diffused and / or directionally reflected light, and convert this into corresponding first sensor signals. On the other hand, the third sensor 23 located in the region of the front side of the banknote detects the light transmitted by the banknote, which is emitted by a light source 24, strikes the banknote obliquely and passes through it, and converts it into corresponding second sensor signals. Due to the obliquely incident on the banknote light from the light source 24 is through the third sensor

so-called dark field transmission image in which the banknote appears bright and its surroundings or background appears dark. The first and second sensors 21 and 22 are also referred to as remission cameras and the third sensor 23 is also referred to as a transmission camera.

Preferably, the line with the sensor elements of the respective sensor 21, 22 or 23 runs substantially perpendicular to the transport direction T of the banknotes, so that with each read-out operation of the sensor line of the respective a sensor waveform along the sensor line is obtained, which corresponds to an intensity profile of the light, which is transmitted or remitted in a direction perpendicular to the transport direction T extending direction of the banknote or remittiert.

The first and second sensor signals generated by the sensors 21 to 23 of the sensor device 20, in particular the corresponding first and second sensor signal profiles, are forwarded to a control device 50 and an evaluation device 51. The evaluation device 51 can be contained in the control device 50 or can also form a separate unit from the control device 50.

In the evaluation device 51, the sensor signals are used after a possible preprocessing to check the banknote, being derived from the respective sensor signals statements about various properties of the respective banknote, such. B. the authenticity or condition of the bill, in particular the degree of soiling, wear and tear, defects and the presence of foreign objects, e.g. Adhesive strips and other stickers, but also office and staples. Contamination, wear and defects can be detected by known evaluation methods from the remission and / or transmission image, the presence of foreign objects using the evaluation of the invention.

Depending on the characteristics of the respective banknote determined in the evaluation device 51, the transport device 10 and the points 11 and 12 along the transport path are controlled by the control device 50 such that the banknote is fed to one of a plurality of output compartments 30 and 31 and stored there. For example, 30 banknotes are stored in a first output tray, the good Condition, in particular no foreign objects such as adhesive strips, while banknotes with bad condition, such as banknotes with adhesive strips, are stored in a second output tray 31. Counterfeit suspect banknotes are placed in another compartment (not shown).

The reference numeral 13 at the end of the transport path shown should indicate that further output compartments and / or other facilities, for example for the storage or destruction of banknotes, may be provided. If, for example, the examination of a banknote shows that it does not fulfill certain status criteria with regard to soiling, wear, defects or existing foreign objects, then this can be sent directly to a shredder for destruction.

In the illustrated example, the value-document processing system 1 further comprises an input / output device 40 for inputting data and / or control commands by an operator, for example by means of a keyboard or a touchscreen, and outputting or displaying data and / or information relating to the processing process, in particular to the respectively processed banknotes.

The value-document processing system 1 shown by way of example is particularly suited to documenting value documents for the presence of foreign objects, such as foreign objects. Adhesive strips and other stickers, to check what is explained in more detail below.

FIG. 2 shows an example of a document of value in the form of a banknote 3, which in the present case is shown only in a highly schematized manner, which is stuck with an adhesive strip 4, which projects slightly beyond the edge of the banknote 3 in the illustrated example. For reasons of clarity The adhesive strip 4 projects beyond the edge of the banknote 3 in a clearly visible manner. However, the following explanations also apply correspondingly to adhesive strips or other comparable foreign objects on banknote 3, which are flush with the edge of banknote 3.

The adhesive strip 4 may basically be any type of adhesive strip, such as e.g. transparent and / or clear and / or matt and / or transparent only in the tested spectral range adhesive tape.

The illustrated banknote 3 has in the region of its lower right corner of a deformation 5, which has also been shown enlarged in the present example for reasons of clarity and may have different causes, such. B. a production-related imperfect cutting edge of the banknote 3 or caused by the transport of the banknote 3 in a banknote processing system distortion. In the illustrated example, the deformation 5 is shown as a projection relative to the remaining course of the lower cut edge of the banknote 3. However, the following explanations also apply mutatis mutandis to all other types of deviations of the outer shape of the banknote 3 from the usual rectangular banknote form.

FIG. 3 shows an example of a transmission image 3 'of the banknote 3 shown in FIG. 2. The transmission image 3' shown here is preferably a so-called dark-field transmission image, which is obtained by transmitting light from the light source 24 (see FIG Fig. 1) obliquely, that is radiated at a significantly different angle of 90 °, with respect to the surface of the transmission camera 23 and hits the banknote 3. The light passing through the banknote 3 is detected by the transmission camera 23 and converted into corresponding first sensor signals, which together give the transmission image 3 '. The light passing past the banknote 3 as well as the transmission camera 23 causes the transmission image 3 'of the banknote 3 to appear in front of a substantially completely dark background 6 in the transmission recording shown here.

The transmission image 3 'of the banknote 3 shows a region 4' with an increased brightness relative to the dark background 6, which is attributable to the fact that the light striking the banknote 3 is scattered by the adhesive strip 4 in the direction of the transmission camera 23 and / or is broken and - in contrast to the incident on the transmission camera 23 passing illumination light - is detected by the transmission camera 23. In the transmission image 3 'of the banknote 3, a region 5' corresponding to the deformation 5 can also be seen.

FIG. 4 shows an example of a remission image 3 ", the banknote 3 shown in FIG. 2, which was taken with one of the two remission cameras 21 and 22 (see FIG. 1) by remitting, ie directing, the banknote 3 or diffusely reflected light is detected and converted into corresponding second sensor signals, which together form the remission image 3 ". In the absence of reflection or scattering of the illuminating light passing past the banknote 3, the remission image 3 "of the banknote 3 also appears in front of a substantially dark background 7. In the remission image 3", a region 5 "corresponding to the deformation 5 of the banknote 3 is also discernible as in the transmission image 3 ', at the upper edge of the position of the adhesive strip 4 corresponding bright area 4' can be seen (see Fig. 3), a corresponding area in the remission image 3 "does not occur. This can be explained by the fact that the Adhesive strip 4 causes only a small backscatter of the incident light, whereby the edge of the banknote 3 superior part of the adhesive strip 4 in the remission image 3 "can not be distinguished from the substantially uniformly dark background 7.

After recording the transmission image 3 'and the remission image 3 "of the banknote 3, both the transmission image 3' and the remission image 3", the course of the edge of the respective image 3'bzw. 3 '' determines, e.g. by the first and second signal values, the signal values in the area of both the image 3 'and. 3 "as well as the background 6 or 7 are compared with a respective threshold value, sensor signals whose magnitude exceeds the predetermined threshold value are in this case assigned to the transmission image 3 'or remission image 3", while sensor signals which fall below the predetermined threshold value are assigned. be assigned to the background 6 and 7, respectively.

Subsequently, an edge detection is performed on the transmission and remission image, in which one of a plurality of edge points T (x, y) and R (x, y) composite course VT or VR of the edge of the transmission image 3'bzw. Remission image 3 "of the banknote 3 is determined, which is exemplified in Figures 5 and 6, respectively.

As already explained in connection with FIGS. 3 and 4, the illustrated edge profile VT of the transmission image 3 'and the edge profile VR of the remission image 3 "show a region 5' or 5" corresponding to the deformation 5 at the edge of the banknote 3, whereas FIG the position of the adhesive strip 4 corresponding area 4 'occurs only in the edge profile VT of the transmission image 3'. In a further step, the first and second edge points T (x, y) and R (x, y) are transformed in such a way, in particular by rotation and / or translation, that the four corners of the edge profile VT of the transmission image 3 'with the The coordinates x and y of the boundary points T (x, y) and R (x, y) are then related to a common coordinate origin, which preferably - as shown in FIG one of the four corners of the edge curves VT and VR coincides.

7 shows that the edge profiles VT and VR in the regions 5 'and 5 "corresponding to the deformation 5 of the banknote 3 can not be distinguished from one another, whereas the first edge profile VT of the transmission image is in the region 4' of the adhesive tape 4 on the banknote 3 differs significantly from the second edge profile VR of the remission image.

Starting from the largely aligned edge profiles VT and VR, a distance value D is then calculated in each case for one or more pairs of edge points T (x, y) of the transmission image and edge points R (x, y) of the remission image, which is a measure of the distance between the first edge points T (x, y) from the corresponding second edge points R (x, y). For example, as the distance value D, the so-called Euclidean distance between the respective two points T (x, y) and R (x, y) is calculated as follows:

Where XT and yT represent the coordinates of the first edge point T (x, y) and XR and yR represent the coordinates of the second edge point R (x, y). In principle, it is possible to calculate one or more distance values D only in certain sections of the two edge courses VT or VR. However, it is preferable to determine the distance values D for many or all of the pairs of first and second edge points T (x, y) and R (x, y) along the margins VT and VR, in order to obtain particularly high levels of adhesive tape on the banknote To recognize reliability.

8 shows a first example of the course of distance values D determined from first and second boundary points T (x, y) and R (x, y) along the y direction of the upper edge of the obtained transmission or remission image. In addition, FIG. 8 shows the distance comparison value A, which was determined in advance on the basis of banknotes which have no adhesive strips or similar foreign objects. The distance comparison value A can be selected depending on the measurement accuracy of the image acquisition. For example, as a distance comparison value A, a length of 1, 2 or 3 pixel sizes of the remission or transmission image may be used. As can be seen from the figure, the distance values D in a region along the y-direction exceed the distance comparison value A, resulting in a significant deviation of the edge profile VT of the transmission image compared to the edge profile VR of the remission image and thus on the banknote 3 located adhesive strip 4 can be closed. In comparison, FIG. 9 shows a second example for the course of distance values D determined from first and second boundary points T (x, y) and R (x, y) along the y-direction at the lower edge of the edge profile VT or VR. Unlike in the area of the adhesive strip 4 located on the banknote 3, those in the region of the deformation 5 of the banknote 3 exceed determined distance values D the associated distance comparison value A not, from which it can be concluded that at this point of the banknote 3 is no tape. With the aid of the method described above or with the aid of the corresponding device, a distinction can thus be made in a simple and reliable manner as to whether the deviations from the edge profile of the banknote detected by image sensors are due to deformations, in particular distortions or stagnation, of the banknote itself or about one located on the banknote Adhesive strips are caused. As a result, it is reliably prevented that a banknote which has only such deformations but no adhesive strips is incorrectly taken out of circulation and, if necessary, destroyed.

Claims

Patent claims

1. Apparatus for checking documents of value (3), in particular banknotes, with

at least one sensor (21-23) for detecting an electromagnetic radiation transmitted by a value document (3) and generating corresponding first sensor signals (3 ') corresponding to the respective electromagnetic radiation transmitted in the region of the edge of the value document (3), and for detecting an electromagnetic radiation remitted by the value document (3) and generating corresponding second sensor signals (3 ") corresponding to the respective electromagnetic radiation remitted in the region of the edge of the value document (3), and

- An evaluation device (51) for checking whether the value document (3) has a foreign object (4), in particular an adhesive strip, taking into account the first sensor signals (3 ') and taking into account the second sensor signals (3 ").

2. Device according to claim 1, wherein the evaluation device (51) is designed to, in the examination of whether the value document (3) has a foreign object (4), in particular an adhesive strip, the first sensor signals (3 '), respectively correspond to electromagnetic radiation transmitted in the region of the edge of the value document (3), and the second sensor signals (3 "), which correspond to the respective electromagnetic radiation reflected in the region of the edge of the value document (3), are compared with one another.

3. Device according to one of the preceding claims, wherein the evaluation device (51) is adapted to

determine one or more first edge points (T (x, y)) based on the first sensor signals (3 '), which correspond to the edge of the value document (3),

- Determine one or more second edge points (R (x, y)) based on the second sensor signals (3 "), which correspond to the edge of the value document (3), and

to compare the position of at least one of the first edge points (T (x, y)) with the position of at least one of the second edge points (R (x, y)), by a spatial distance between the respective first and second edge points and / or determine an area between the first and the second boundary points, wherein the positions of the first and second boundary points (T (x, y), R (x, y)) are compared with each other, the corresponding points along the edge of the value document (3 ) are and

check, on the basis of the spatial distance and / or the area, whether a foreign object, in particular an adhesive strip, is present in the region of the edge of the value document.

4. The device according to claim, wherein the evaluation device (51) is adapted to compare the spatial distance with at least one predetermined distance comparison value (A) and / or the area with at least one predetermined area comparison value (F) and in the case when the distance the distance comparison value (A) and / or the surface with the area comparison value (F) exceeds the affirmative presence of a foreign object (4), in particular an adhesive strip, and otherwise deny the presence of a foreign object (4), in particular an adhesive strip.

5. Device according to claim 4, wherein the at least one distance comparison value (A) / area comparison value (F) corresponds to a distance value / area value determined on the basis of at least one value document on which there is no foreign object, in particular no adhesive strip.

6. Device according to one of claims 3 to 5, wherein the evaluation device (51) is adapted to the position of the at least one first / second edge point (T (x, y) and R (x, y)) by comparing the first / second sensor signals (3 'and 3 ") with at least one

Determine threshold.

7. Device according to one of claims 3 to 6, wherein from the first sensor signals (3 ') by means of edge detection of the course of the value documentum in transmission is determined and from the positions of a plurality of first boundary points are determined, and wherein from the second sensor signals (3 ') by edge detection of the edge course of the value document in remission and from the positions of a plurality of second boundary points are determined.

8. Device according to one of claims 3 to 7, wherein the evaluation device (51) is adapted for the spatial distance between the respective first edge point and the respective second edge point along the edge of the value document (3) the respective first Edge point corresponds to determine a distance value (D), which represents a measure of the spatial distance of the respective first edge point (T (x, y)) from the respective second edge point (R (x, y)).

9. Device according to one of claims 3 to 8, wherein the evaluation device (51) is adapted to

to determine a distance value (D) for each of a plurality of pairs of first and second edge points and to check whether a predefined minimum number (N) of the pairs of edge points exceeds the distance comparison value (A), and

in the case where the distance value (D) exceeds the distance comparison value (A) for at least a predetermined minimum number (N) of the pairs of edge points, affirming the presence of a foreign object (4), in particular an adhesive strip, and otherwise the presence of a foreign object (4), in particular an adhesive strip to deny.

10. Device according to one of claims 3 to 9, wherein the evaluation device (51) is adapted to determine a number (n) of distance values (D) which are greater than the distance comparison value (A), and the test whether the value document (3) comprises a foreign object (4), in particular an adhesive strip, by means of a comparison of the determined number (n) of distance values (D), which are greater than the distance comparison value (A), with a predetermined minimum number (N ) of distance values.

11. Device according to one of claims 8 to 10, wherein the at least one distance value (D) is the Euclidean distance between in each case a first and a second edge point (T (x, y), R (x, y)).

12. Device according to one of the preceding claims, wherein the at least one sensor (21-23) for the spatially resolved detection of the value document (3) transmirtierten and of the document of value rrüttierten electromagnetic radiation and for generating corresponding first and second sensor signals (3 'and 3 ") is formed.

13. Device according to one of the preceding claims, wherein the at least one sensor (23 or 21 - 22) for generating a composite of first sensor signals transmission image (3 '), in particular a dark field transmission image, and a composite of second sensor signals remission image (3 ") is trained.

14. value document processing system (1) with at least one device (2, 8, 10 - 13, 30, 31, 50) for processing, in particular for conveying and / or counting and / or sorting of value documents (3), in particular banknotes, and with a device (21-23, 51) for checking value documents (3) according to one of the preceding claims.

15. Method for verifying documents of value (3), in particular banknotes, comprising the following steps:

Detecting an electromagnetic radiation transmitted by a value document (3) and generating corresponding first sensor signals (3 '),

Detecting an electromagnetic radiation remitted from the value document (3) and generating corresponding second sensor signals (3 ") and

Checking whether the value document (3) has a foreign object (4), in particular an adhesive strip, taking into account the first and second sensor signals (3 ', 3 ") transmitted respectively in the region of the edge of the value document (3); Reflect electromagnetic radiation.