What is a vehicle pollution check



description


The invention relates to a method for testing the degree of pollution of recording media, in particular banknotes, with the help of a transmitter-receiver arrangement and evaluation of the received measurement signals as a measure of the degree of pollution, the recording media are at least partially printed with colors that are for light in are transparent to a non-visible spectral range.


The determination of the degree of wear and tear of bank notes is known from a large number of documents. As a rule, unprinted areas of the banknote surface, such as the edge (DE-A-23 10 882) or unprinted areas within the banknote surface (US-A-2, 950, 799) are used for testing. If there are no unprinted areas on the bank note or if they are insufficient, the test must be carried out within the printed image of the bank note. In contrast to the investigation of unprinted areas, it must be taken into account that the light reaching the photodiodes is modulated by the print pattern present along the scanning track. In this connection, DE-A-27 52 412 mentions a test method which, inter alia. is based on the basic idea that a non-soiled bank note along a track running in printed areas has a certain number of contrast jumps of a certain height corresponding to the existing print pattern, which, added up along the track as signal values, serve to form a standard signal. If a bank note is soiled, the contrast decreases, so that the test level added up for this note deviates more or less from the standard level of a clean note, depending on the degree of soiling. The difference can be used as a measure of the pollution.


The method provides good results as long as the track used to form the standard signal is precisely adhered to during subsequent tests. However, if there are deviations from the track, which cannot always be avoided, the photodiode scans a more or less strongly changed print pattern in the vicinity of the original track, which inevitably leads to changes in the test level regardless of the contamination. Depending on the strength of the discrepancies, the test level is therefore when several banknotes with the same soiling are scanned or when the same banknote is scanned multiple times or when the same banknote is scanned multiple times within a scrap area, which excludes an assessment of the degree of soiling with a narrow tolerance and divided into several levels.


Another method for checking the degree of wear and tear or the contamination of bank notes is known from US Pat. No. 3,759,382. Here the transmittance of certain areas of the bank note in the spectral range of visible blue light is measured. The increase in opacity, which serves as a criterion for the degree of soiling, is said to be most pronounced in this spectral range. However, this measurement can only be carried out sensibly in unprinted areas of the bank note, since a measurement in the printed image area of ​​the bank note would falsify the measurement signal in an uncontrolled manner due to the local fluctuations in the transmittance caused by the printing inks.


The object of the invention is therefore to propose a method and a device for testing the degree of wear and tear of banknotes in which the test results of the same dirty notes within wide limits regardless of track deviations within a narrow range, even when testing in printed areas of the note Lying area.


The object is achieved in a method of the type mentioned by the features specified in the characterizing part of the main claim.


When designing securities and thus also bank notes, use is often made of several printing techniques to increase the security against forgery and forgery. In the case of banknotes, for example, surface areas are found that are executed using the very complicated and expensive steel rotogravure printing technique, while other surface areas, for example for the design of background patterns, are printed using flat printing technology.


When examining bank notes it has now been shown that many of the colors used are transparent to IR light. It has also been shown that soiling when irradiated with IR light shows the same optical properties as when irradiated with visible light.


If a bank note is illuminated in the areas printed with IR-permeable ink with light, which inter alia. also contains IR components, but filters only the IR components out of the remitted light reaching the photodiodes, then the received signals are usually largely freed from the modulation normally resulting from the print pattern in visible light. By skillful selection of the measuring tracks, the test level can be kept within a narrow range even if there are deviations from the test track with the same contamination, but possibly with a different print pattern, in the case of a track deviation. Since the print pattern is eliminated, the test track can also lead from the unprinted area of ​​a banknote into the printed area, which means that there is a high degree of flexibility in the selection of the test tracks for different banknotes.


The test within the non-visible spectral range is not limited exclusively to the IR range. Printing inks which are transparent to light in other spectral ranges of the non-visible spectrum can of course also be used for testing within the meaning of the invention.


An exemplary embodiment of the invention is described below with reference to the accompanying drawing. Show in it:

FIG. 1 shows the highly schematic division of a banknote surface into IR-permeable and IR-impermeable printing areas,

FIG. 2 shows the simplest embodiment of a device for checking bank notes according to FIG. 1.



Fig. 1 shows a bank note 1, the print image is arranged so that a narrow edge of the note remains unprinted. The areas 2 with double hatching within the print image - arranged randomly in this example - are printed with the corresponding colors that are opaque to IR light. On the remaining surface areas 3, which are hatched in the figure, there is a print pattern whose printing inks are transparent to IR light. 4 is a randomly selected test track which alternately overflows areas printed with IR-permeable and IR-opaque ink. According to the invention, the marked areas are basically B.i, B2 or B3 suitable for dirt testing. However, it is sufficient to only include one of the areas, for example B2 to be admitted to the examination.


However, the test is carried out along the other areas (B.1 + B2) possible, although the test track partially runs in the completely unprinted area of ​​the banknote. Even if the test device does not always precisely scan a test track that has been adjusted once due to mechanical inadequacies, the spread of the measured values ​​can be kept within narrow limits because the influence of the locally strongly varying print image is eliminated and the contamination is usually evenly distributed over larger areas .


2 shows an example of a test device with which the method according to the invention can be carried out.


The bank note 1 transported past the checking device 7 in the direction of the arrow 6 is illuminated in the area of ​​the checking track with the aid of two tungsten lamps 8 with light which has a high IR component beyond the visible range. The light remitted by the bank note reaches a lens arrangement 12 via a diaphragm 9. A filter 10 is connected in the beam path of the optical system, which allows only the IR portion of the remitted light to reach a photodiode 15, which in a known manner the Converts lighting fluctuations due to soiling into corresponding electronically evaluable signals. The measuring signal, which is modulated as a function of the contamination, is added up along the scanned area and the total values ​​are compared with a nominal value after passing through the measuring track.


Fig. 2 shows the possibility of decoupling the IR component exclusively on the receiver side. Depending on the application, it is of course also possible to use commercially available IR light-emitting diodes to irradiate the test surface exclusively with IR light, whereby the filter can, under certain circumstances, be retained to compensate for the influence of extraneous light.



Expectations

1. A method for checking the degree of contamination of recording media, in particular banknotes, with the aid of a transmitter / receiver arrangement and evaluation of the received measurement signals as a measure of the degree of contamination, the recording media being at least partially printed with colors that are transparent to light in an invisible spectral range are, characterized in that the recording medium is irradiated by the transmitter arrangement with light, which contains components from this invisible spectral range and the receiving arrangement receives the remitted components of precisely this light along one or more measuring tracks in the area of ​​the translucent colors.
 

2. The method according to claim 1, characterized in that the measuring signal of the measuring tracks is evaluated over the unprinted and printed areas of the recording medium.
 

3. The method according to claim 2, characterized in that the measurement signal modulated by the contamination is added up along a scanned area and the sum values ​​are compared with a target value after passing through the measurement tracks.
 



Claims

1. A method of checking the degree of contamination of data carriers, in particular bank notes, by aid of a transceiver arrangement and the evaluation of the received measuring signals as a mesure of the degree of contamination, the data carriers having ink printed on at least part of them which is transparent in a non-visible spectral range, characterized in that the data carrier is irradiated by the transmitter arrangement with light containing parts of this non-visible spectral range, and the receiver arrangement receives the remitted parts of this same light along one or more measuring tracks in the range of the transparent inks.
 

2. A method as in claim 1, characterized in that the measuring signal of the measuring tracks over the unprinted and printed areas of the data carrier is evaluated.
 

3. A method as in claim 2, characterized in that the measuring signal modulated by the contamination is added up along a scanned area, and the sum values ​​are compared with a desired value after the measuring tracks have been covered.
 



Revendications

1. Procédé pour contrôler le degré d'encrassement de supports de tracés, notamment de billets de banque, au moyen d'un dispositif émetteur- récepteur et pour analyer des signaux de mesure reçus afin de définir le degré d'encrassement, les supports de tracés étant imprimés au moins en partie avec des couleurs qui laissent passer la lumière dans une plage spectrale non visible, caractérisé en ce que le support de tracés (1) est soumis par le dispositif émetteur à une irridiation avec une lumière de qui contient des partiesère cette plage spectrale non visible et en ce que le dispositif récepteur reçoit les parties réfléchies de cette lumière le long d'une ou plusieurs voies de mesure (4) in the zone des couleurs laissant passer la lumière.
 

2. Procédé selon la revendication 1, caractérisé en ce que le signal de mesure provenant des voies de mesure (4) est analysis dans les zones non imprimées et les zones imprimées du support de tracés (1).
 

3. Procédé selon la revendication 2, caractérisé en ce que le signal de mesure modulé par les encrassements est soumis à une sommation le long d'une zone d'exploration et en ce que les valeurs de sommation sont comparées avec une valeur de consigne après course des voies de mesure (4).