CH649856A5 - DOCUMENT AUTHENTICATION APPARATUS. - Google Patents

Description

The present invention relates to document authentication devices, such as tickets, checks and credit cards.

Numerous devices are known in the prior art which serve to authenticate documents and, more particularly, to authenticate monetary effects in order to make change or to establish a credit for the sale of goods or services. These prior art devices generally operate on the basis of one of two different principles or on a combination of the two principles. First, one can direct light from a source towards the document to be authenticated and capture the reflected or transmitted light in order to determine an optical characteristic of the document examined. According to another means, and more particularly in relation to the currency of the United States of America, magnetic properties of the ink with which the ticket was printed can be measured during the authentication operation. It is also possible to use a combination of optical and magnetic means.

While the prior art means for authenticating documents work more or less successfully, they have a number of shortcomings. First, they are not as flexible as would be desirable and most of them are limited to the authentication of a particular type of document, for example a 1 or 5 US dollar bill. 'America. Second, they are not as reliable as would be desirable, and most of them will reject what is an authentic document while accepting a false document. Another shortcoming of prior art document authentication devices is that, once they have been set up to authenticate a document of a particular type, they cannot be easily modified to make them accept a document of a different type.

An object of the invention is to provide a universal document authentication device which overcomes the defects of the devices. authentication of documents of the prior art. Another object of the invention is to propose a document authentication device which makes it possible to authenticate more than one type of document.

Another object of the invention is to provide a universal document authentication device which is more reliable than the authentication devices 55 of the prior art.

Another object of the invention is to propose a document authentication device which can easily be modified to have a document of a different type authenticated than that for which the authentication device was initially set. 60 To this end, the invention is defined in claim 1.

The following description, intended to illustrate the invention, aims to give a better understanding of its characteristics and advantages; it is based on the appended drawings, among which:

65 fig. 1 is a sectional view of a form of the universal document authentication device according to the invention;

fig. 2 is a block diagram illustrating the various components of the apparatus;

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fig. 3 is a simplified view illustrating part of the circuit of the microprocessor of the device;

fig. 4 is a simplified view of another part of the microprocessor circuit of the device;

fig. 5 is a simplified view of another part of the circuit of the microprocessor of the apparatus;

fig. 6 is a simplified view of the photosensitive network and of the circuit which is associated therewith of the apparatus;

fig. 7 is a simplified view of the keyboard and of the selection switching system of the apparatus;

fig. 8 is a flowchart illustrating the initial part of the general program of the device;

fig. 9 is a flowchart illustrating the end of the initial part of the general program of the device;

fig. 10 is a flowchart illustrating the prior limit regeneration routine in the apparatus;

fig. 11 is a flowchart illustrating the learning routine of the apparatus, and FIG. 12 is a flowchart illustrating the authentication routine of the apparatus.

As shown in fig. 1, the universal document authentication device described here comprises a housing 10 having an inlet opening 12 which leads into the space formed between an upper guide 14 and a lower guide 16. The base 18 of the housing 10 carries a reversible motor 20, the shaft of which has a pinion 22 intended to drive a chain 24. The chain 24 is engaged with a first pinion 26 intended to drive the lower roller 28 of a first pair of rollers comprising a roller pressure 30 pushed so as to come into contact with the roller 28. The chain 24 passes over a free sprocket 32 mounted on the housing 10 so as to allow adjustment of the chain tension, in a manner known in the art, vis-à-vis a pinion 34 intended to drive an intermediate roller 36 with which is associated another roller 38, elastically pushed so as to come into contact with the roller 36. From the pinion 34, the chain 24 passes to a pinion 40 intended to drive a lower roller 42 associated with an upper roller 44 which is elastically pushed into contact with the lower roller 42. From the pinion 42, the chain passes over a pinion 46 and returns to the pinion 22. The pinion 46 is intended to drive a roller 48 with which an upper roller 50 is associated.

According to one form of the universal document authentication device, the front edge of the document to be authenticated is inserted into the opening 12 so as to interrupt the passage of light between a source 52 and a detector 54. In response to this action, the motor 20 is excited forward so as to cause the roller 28 to advance the bill along the passage formed by the upper guide 14 and the lower guide 16. When the bill arrives at a predetermined location in the path transport, light from a source 56 is prevented from exciting a photoelectric cell 58 to a level sufficient to initiate another operation by the machine. In other words, the interruption of this light beam by the front edge of the ticket itself or by the front edge of the print results in another operation of the apparatus of the invention. The system is designed so that this ticket position detection device starts the authentication operation, for example when a predetermined area of the ticket is above a window 60 formed in the lower guide 16. The window 60 is normally closed by a shutter 62 designed to open, for example following the excitation of a solenoid 63. Preferably, the side of the shutter 62 which is exposed to light when the shutter is closed and has a reflective element to allow calibration.

When window 60 opens and the authentication operation is to be carried out, light from a source 64 is intended to illuminate the area of the document located above window 60. The light reflected by the document is focused by a lens 66 on an image forming pad 68 having an array 70 of one hundred and twenty-eight distinct photosensitive elements, for example. The microprocessor circuit which responds to the various input signals of the device can be housed in a sub-housing 72 indicated schematically in FIG. 1. As will be explained more fully below, the elements of the network 70 can be requested a certain number of times during the passage of documents in the authentication apparatus, in order to provide as many area images. predetermined document that this is desirable or necessary.

As can be seen in the block diagram in fig. 2, the device comprises an electrical supply 74, intended to supply the potentials suitable for the operation of the drive motor, and logic units of the system from an alternating current source located on the assembly on which the device of the invention is used. More specifically, the power supply 74 supplies electrical energy to the transport motor 20, to the document position sensor comprising the elements 52, 54, 56 and 58, to the light source 64, to the image sensor 68, to the clock pulse generator 76, to the logic control device 78 of the transport device, to the unit 80 for temporary storage of data, to the data manipulation unit 82, to the decision-making unit 84 authentication, to the synchronization unit 86, to the image sensor control logic unit 88 and to the buffer memory 90. The delivery of electrical energy is indicated in FIG. 2 by the symbolic notation PWR. The clock pulse generator 76 supplies input clock pulses to the device 78 for controlling the input motor, to the unit 80 for temporary storage of data, to the unit 82 for handling data, to the authentication decision unit 84, to the synchronization unit 86, to the logic device 88 for controlling the image sensor and to the buffer memory 90. The delivery of synchronization pulses is indicated in FIG. 2 by the symbolic notation CLK. When a ticket enters the transport system, the document position sensors 52 and 54 produce a signal which actuates the device 78 for controlling the transport device via a channel 92, in order to send to the device 20 for transport control a forward signal via a track 94. When the anterior edge of the ticket, or the anterior edge of the print, reaches the detection device 56, 58, an input signal is applied via a track 96 to the synchronization device to the logic device 88 for controlling the image sensor via a channel 95 and to the buffer memory 90 via a channel 97. The delivery of a synchronization signal is indicated in FIG. 2 by the symbolic SYNC notation. This document position signal can also be used to drive the solenoid 63 to open the shutter 62. When an area of the ticket or document from which the image is to be read arrives at window 60, the image sensor 68 is used to supply output data to the buffer memory 90 via a channel 98. Each image comprises one hundred and twenty-eight output signals, which are compared with a threshold voltage, so as to produce signals logic output 1 which can be for example continuous pulses of 5 V, or logic output signals 0 which can be for example continuous levels of 0 V. In response to the synchronization signal sent on channel 96, the information passes from the buffer memory 90 to the unit 80 for temporary storage of data via a channel 99. In addition to the synchronization signals already identified, the unit 86 supplies a synchronization signal to the imitates 80, 82 and 84, respectively, by through channels 100, 102 and 104. The respective channels 106 and 108 provide two-way communication between units 80 and 82 and between units 82 and 84. Channel 110 provides two-way communication between units 80 and 84.

Once the image has been sent to the control system in the manner indicated above, the data manipulation circuit adds the number of high level bits contained in the image and stores the sum in the storage register 80 temporary. The value of the image depends on the amount of light that has been reflected from the document, which is itself a function of the type and condition of the paper and ink used, as well as the image printed. on the document at the location where the image was taken. Bit summation done in this way reduces

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the effect of an image position shift in case the document was not saved accurately.

It is envisaged that as many images as one can be picked up, so that after the desired number of images has been picked up, each of the images is in its own temporary storage register. At this time, the authentication operation is carried out by taking into account the distinct value of each image or by an arithmetic combination of two or more image values. The resulting values are then checked so that it is determined whether or not they are within predetermined limits of an authentic document of the type examined. As will be discussed more fully below, the authentication apparatus may contain acceptable limits for several different documents, in which case the image data is checked, so that it is determined whether it falls within the acceptable limits of any of the documents. If the documents are considered authentic, the control device produces an "authentic" pulse on channel 112 and the document continues to move in the device until it leaves, where it can stack in a well-known manner. in the technique. If it is determined that the ticket is not authentic, circuit 84 produces a signal on channel 114 indicating that the ticket does not fall within acceptable limits, so that circuit 78 produces a signal on channel 94 and that the transport device 20 changes direction to bring the ticket back to the customer.

The simplified diagram of the calculating part of the system is presented in relation to FIGS. 3 to 5, together with the image sensor, transport motor, etc. control circuits. In a spirit of clarity, the interconnections between FIGS. 3 and 4 have been designated by the reference letters a to mm in the two figures. Similarly, the interconnections between FIGS. 4 and 5 have been designated by the reference letters nn to eee in the two figures. In the assembly shown in these figures, ZI is the central processing unit, which can be, for example, an Intel 8085A microprocessor. Z2 is an Intel 8355 pad providing a combination of program memory (fixed memory) and sixteen input or output lines. Z3 is an Intel 8155 pad giving a combination of working memory (direct access memory), a timer, and twenty-two input or output lines. These three pads, in relation to Z8, used to select the pad with which the central processing unit communicates, form the brain of the system. The central processing unit shares the lower 8 bits of address with 8 bits of data. Z3 is provided with a learning switch SWA and switches SW1 and SW2 which determine its mode of operation in a manner known in the art.

Z4, which can be, for example, an 8 bit Intel 8212 input / output device, keeps the address bits constant, so that Z5 and Z6 can function properly. Each of the Z5 and Z6 units can be, for example, an Intel 5101 chip constituting a static MOS direct access memory of 256 x 4 bits. The Z5 and Z6 units are supplied with a continuous potential of +5 V when the system is switched on and by a 2.4 V battery when the supply fails. Pads Z5 and Z6 contain the learned limits of a document and can be erased so that new limits are taught relative to a different document, if desired and when desired. It should be understood that, when two or more types of documents or tickets are provided, it is necessary to add as many pairs of pads similar to Z5 and Z6. These additional pairs will be wired in exactly the same way as Z5 and Z6, except that the first additional pair will be linked to pin 11 of Z8 by its IEC pins (pin 19) and the second pair will be linked to pin 10 of Z8 by the corresponding pins. By way of example, and to avoid repetition, these additional types have been indicated by B in a circle close to pin 11 of Z8 and by C in a circle close to pin 10 and Z8.

If the supply stops, it is necessary that Z5 and Z6 are disabled. The function of the unit ZI is to detect such a supply interruption and to invalidate Z5 and Z6 in this way. This tablet ensures

also the order required for the application and interruption of the power supply, this protecting the limits which must not be altered as a result of a power supply failure.

The unit Z9 is a divide by sixteen counter, which divides the clock pulse of the central processing unit so as to produce a clock pulse intended for said sensor and which also supplies the input signal d timer Z3.

The ZIO and ZI 1 units constitute a digital-analog converter which is controlled by the input-output line Z2 in order to allow the central processing unit to continuously correct the variations in optical reading by adjusting the voltage of threshold applied to the optical reading comparator. The units Z12 and Z16 count the number of optical read pulses that exceed the threshold, and the resulting 8-bit image representation can be applied to ZI via 8 lines of Z3.

The Z14 unit is a seven-segment display device excited by seven lines of Z3 via a Darlington ZI 3 network, which adds current to the input signal. This display device Z14 provides an indication of the status of the authentication device to the employee.

Unit Z15 is a block of four operational amplifiers which can be used to create a pulse on the edge of the print in response to sensor 58. This circuit has a switch which can be switched so that synchronization begins on the edge of the ticket rather than on the edge of the print. Preferably, a print edge signal is used, instead of the edge of the document, to minimize the effects of mismatches of the print edge with the edge of the document.

The Z18 unit is an optical reading comparator, the output signal of which is a logic level 1 if the optical reading level coming from an element of the pad exceeds the threshold, which is the output signal of the digital-analog converter. formed by ZIO and ZI 1. The output signal of ZI 8 is buffered via a transistor, so that it will have the necessary excitation capacities, and is used as an input signal for the optical reading counters Z12 and Z16.

In fig. 3, 4 and 5 is also indicated, by way of example, the conventional assembly (resistors, capacitors, transistors, etc.) of the units ZI to Z18. Numerical values and references are given only by way of example, and those skilled in the art can easily find others which are equivalent to them. The references of the units ZI to ZI8, given by way of examples, are the following:

ZI: 8085A,

Z2: 8355/878755,

Z3: 8155,

Z4: 8212,

Z5 and Z6: 5101L3,

Z7: LM 3302,

Z8: 74LS138,

Z9, Z12 and Z16: 74LS93,

ZIO: ZN425E,

ZI 1: ZN424,

ZI 3: UNL2003,

Z14: MAN71 / 72,

ZI5: LM324,

ZI 7: 74LS74,

Z18: LM710.

As shown in fig. 6, and as explained above, the image sensor Z19 is a linear array of one hundred and twenty-eight distinct photosensitive elements. The ZI sensor 9 can for example be a reference unit RL128G. It will be readily understood that it is possible to use a planar network rather than a linear network. The sensor receives the potentials + 5V and —10 V, as well as a clock signal and a start signal. The clock signal is produced by the unit Z9 in fig. 3, this signal being the clock signal of the central processing unit divided by a factor 2.4, 8 or 16. By way of example, a clock signal is represented divided by the factor 4. The start pulse signal is produced by the use of three counters Z20, Z21 and Z22 (e.g.

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reference counters 74LS161), which count the clock pulses from a preloaded number positioned at a charging instant by means of a number which is determined by twelve connections indicated in W1 to W12 in fig. 6. These counters advance until Z22 produces a carryover, which reloads the preset number, after which the process repeats. The number positioned by the jumpers W1 to W12 then determines the duration separating optical readings coming from the pad Z19. As shown in fig. 6, part of the start signal is controlled from two locations. This means that this part is controlled from Z22 and from a transistor shown in FIG. 4, the two locations being wired in the OR circuit. The carry-over signal from Z22 is a self-circulating signal which is repeated without any intervention from the central processing unit. The other signal arriving in this circuit, and designated by starting in fig. 6, is produced by a combination of the Z17 printing edge detector and the central processing unit. Its function is to reload the counters, so that the count value is in synchronism with the position of the bill. When a banknote has been inserted into the mechanism, it is finally transported to the location of the on-board detector 58, which produces a pulse destined for the scale of Z17 and destined for the central processing unit. The flip-flop output signal is high, which pulls the start signal down in order to bring the recharging of the counters Z20 to Z22, regardless of their count value at that time.

The central processing unit enters the stake and clears the scale, which releases the start signal, and counting resumes. Thus, the network is in synchronism with the position of the document. This start signal is also shown in fig. 4 as returning to the other flip-flop of ZI 7 via a transistor, so as to effectively apply to the central processing unit a locked start pulse, which normally lasts a single clock period, which allows the central processing unit to recognize that the pulse has been produced.

The optical reading information from the image sensor is applied, in the form of a voltage difference, at two pins. Thus, a differential amplifier, for example Z23, can be used to create an optical read signal at the useful amplitude. The output signal of the amplifier Z23 constitutes the input signal of the microprocessor circuit illustrated in fig. 3 to 5.

As can be seen in fig. 7, a support 116 carries the usual group of push buttons, indicated as a whole by 118 and constituting the keyboard input of the microprocessor illustrated in FIGS. 3 to 5. This support 116 also includes a reading display member indicated as a whole by 120. There is also provided according to the invention a set of switches with three positions, indicated as a whole by 122, making it possible to adjust the microprocessor on particular operations used in the application of the invention. More specifically, a mode switch 124 is designed to be placed in one of three positions. The first position, designated by RES, indicates a state or mode in which the microprocessor will reposition previous limits. The second position of the switch, indicated by LRN, indicates a learning mode, in which a group of microprocessor storage units receives a group of limits, relative to which future documents of a particular type will have to be judged. In the third mode, indicated by VAL, the system is set for authentication, that is, to determine if the optical reading output signal, produced from a particular document, falls within the limits previously data for this particular type of ticket. A second three-position switch 128 is provided with special functions which may be, for example, reading, indicated by RD, erasing, indicated by CLR, or a special function according to which the present limits are modified, which position is indicated by NLIM in fig. 7.

We can better understand the operation of the universal ticket or document authentication device in question by referring to the flowcharts in FIGS. 8 to 12. As can be seen in fig. 12, at the start of the program, the transport motor is stopped, the shutter 62 is closed and the calibration image on the back of the shutter is in place (A). In a first step, it is possible to light the lamp 10 and apply the electrical potential to the control device (B). The resulting image, which is focused on the network 70, is compared with a stored calibration value (C) and, if the value is correct, the program is carried out. If this is not the case, the threshold voltage is adjusted (D) and the comparison is made again until the correct value is obtained. At this point, a decision must be made and indicated whether a special function is requested or not (E). If so, the particular function is detected (G) and performed (H, I or J), and the system returns to the start (K). If no special function is requested, the next decision is whether or not a document or ticket has been inserted into the authentication device (L). If not, the program returns to the beginning (M). If this is the case, the engine starts, the solenoid 63 is energized and the shutter 62 is removed (N).

It is possible, if this is desirable, to provide the authentication device with a means allowing a simple test to be carried out on the back of the document in question. Since such a test, by itself, is not part of the invention, it will not be discussed in detail. If such a test has been planned, the back examination circuit is validated at this time.

Then, the unit waits for the detection of the anterior printing edge in the preferred form (P). If no edge is detected (Q) within a reasonable time, the motor reverses (R) in order to return the object, whatever it is, which has been inserted, then the system returns to the start of the program ( S). If the edge has been detected (Q), the system automatically synchronizes the network with the edge, so that the appropriate ticket area is examined. This may require an optional operation of waiting for the area to reach window 60 (T) (see fig. 9). When the area has reached the window, the network is called up and the desired image representation or representations are taken and stored (U). If the system has the function of creating arithmetic image data other than the simple images obtained, this is done during the next program operation (V). When this has been done, the function switches are requested to determine that the operation must then be carried out (W). If the system is simply set to examine the document, as in the case where one wishes to know what data is in a particular location on the document, one can, after this information has been read, evacuate the document and the stack (X), after which the program returns to the beginning

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If the function switch has been set so that the previous limits are renewed, the program continues as shown in fig. 10, where the boundaries are first placed in the appropriate place (a2). Then, the pointer is positioned on the temporary limits (b2) and a pointer is positioned on the suitable limit area (c2) in the manner determined by the switch for the document type. Then, the data located at the temporary pointer is sent to the limit pointer (d2). It is determined whether or not all limits have been transferred (e2). If this is not the case, the two pointers are moved to the following address (f2), until all the limits have been transferred, after which the document is evacuated and stacked (g2) and the program returns at the start (h2).

If, following the preliminary part of the program illustrated in fig. 8 and 9, the system has been placed on a learning program, the program continues as shown in fig. 11. As shown in fig. 11, in the learning mode, the first operation consists in placing the limits in the appropriate location (a3). Then, the limits are placed in the temporary storage register (b3). The pointer is positioned on the first data image (c3), then a pointer is positioned on the first boundary of the appropriate type (d3). This first limit will be the lower limit of the particular type. A comparison is made between the image data and the positioned limit (e3). If the data s

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is below the set limit, the data is then sent to the lower limit register (f3) and the program continues. If the data is greater than or equal to the set limit, the program continues without passing the data into the lower limit register. In the continuation of the program, a pointer is positioned on the next or upper limit of the image (g3) and a comparison of the data with the limit is performed (h3). If the data is greater than the upper limit set, it is placed in the upper limit register (i3) and the program continues. If the data is less than or equal to the upper limit, it must be decided whether or not all of the images have been examined (j3). If this is the case, the document is evacuated and stacked (13) and the program returns to the start (m3). If not, the pointer is positioned on the next image data for comparison with the lower limit (k3) and the program continues. This continues until sufficient information has been provided to the system to form a basis for authentication.

Leaving aside, in a spirit of simplicity, the arithmetic image data which could involve negative numbers, it is clear that the smallest possible lower limit is 0, limit for which all the elements of the network are dark, and the highest possible upper limit would be equal to the number of elements of the network, where all the elements are illuminated. Before a learning process begins, the special function "deletion of limits" is carried out, this program positioning all the lower limits with the largest possible values and the upper limits with the smallest possible value. After the data has been extracted from the document to be studied, the process begins. In the program, type switches are used if more than one type of document is to be handled by the system, so that the new limits can be placed in the appropriate storage area. First, the data of the first image is compared with the first limit, or lower limit of the limit memory, and, if it is less than this limit, the data is placed in the limit location. Then, data image # 1 is compared with the next limit, or upper limit, and, if it is larger than this limit, the data is placed in the limit location. This is done until all image data has been studied. More specifically, if it is assumed that the limit erasure function has been implemented and that there are one hundred elements in the network, the first and the second limit storage register contain 100 and 0 respectively. assumes that the first image of an inserted document has a value equal to 55. The learning program sees that 55 is less than 100 and that 55 is greater than 0, so that, as a result, the first and the second register limit memorization are fixed at 55 and 55. If the first image of the following document produces the number 50, the registers will be positioned at 50 and 55. If the following number is 57, the registers will be positioned at 50 and 57. If a document with a value of 52 then passes through the machine, the limits will remain unchanged.

We present below a particular example corresponding to a type B document, using the output limit program to produce the output signal. In this example, a four image system is used for each document, with a maximum value of 127 for one image. The first output signal is established after the clear limits function has been performed. The second output signal follows the passage of the first document studied, which produces images having values of 49, 53, 56 and 60. As can be seen, the second document produces studied data which are lower than all the locations , while the third document is superior to the two previous documents for the locations examined. Again, when a representative number of documents of the type under consideration has been studied, the apparatus is set to authenticate documents of this type.

LEARNING TYPE B

READ AFTER ERASING LIMITS L001 = 127: 000 L002 = 127: 000 L003 = 127: 000 L004 = 127: 000

00 OF THIS TYPE OF TICKET WAS STUDY READING AFTER FIRST DOCUMENT

L001 = 049: 049 L002 = 053: 053 L003 = 056: 056 L004 = 060: 060

01 OF THIS TYPE OF TICKET HAS BEEN STUDYED READING AFTER SECOND DOCUMENT

L001 = 022: 049 L002 = 023: 053 L003 = 028: 056 L004 = 027: 060

02 OF THIS TYPE OF TICKET WERE STUDYED READING AFTER THIRD DOCUMENT

L001 = 022: 056 L002 = 023: 059 L003 = 028: 061 L004 = 027: 062

03 OF THIS TYPE OF TICKET WERE STUDYED

When the device of the invention must perform an authentication function, it follows the program presented in FIG. 12. First, the limit pointer is positioned on the first limit, or lower limit of this first type (a4). The data pointer is positioned on the first image (b4), and a comparison is made between the data and the limit (c4). If the data is below the limit, it must be decided whether or not there is rejection of the last type of document to be examined by the authentication device (d4). If this is not the case, the limit pointer is positioned at the first limit, or lower limit, of the following type (e4), and a comparison is made between the data and this limit. If the decision is to reject the last type of document to be examined by the machine, the engine changes direction (f4), the document is returned to the client, and the program returns to the start (g4). If the data is greater than or equal to the lower limit, the limit pointer is positioned on the next limit, or upper limit (h4), and the data is compared with this limit (i4). If the data is greater than this limit, it must again be decided whether or not the last type of document to be examined by the authentication device (d4) will be rejected. The results of this decision are the same as in the case where the comparison with the lower limit indicated that the deal was less than the lower limit. If the comparison between the data and the upper limit indicates that the data is equal to or less than the upper limit, it must be decided whether or not this is the last image to be examined (j4).

If this is not the case, the pointer is positioned on the next or lower limit and on the next image (k4). If the last image has been examined and if a back sensor is used, it must be decided whether or not the back sensor has produced a correct indication (14). If not, the engine reverses (f4) to return the document to the client and the program returns to the start (g4). If the back sensor produces a correct test result, a document authentication signal is formed for this particular type (m4), the document being evacuated and stacked (n4) and the program returning to the start (p4).

It can be seen that the aims of the invention are achieved. A universal document authentication device is proposed which is more precise and more reliable than the authentication devices of the prior art. The apparatus of the invention can authenticate more than one type of document. It can easily be set to change the type of documents to be authenticated.

Of course, those skilled in the art will be able to imagine, from the device whose description has just been given by way of illustration and in no way limitative, various variants and modifications that do not depart from the scope of the invention.

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10 sheets of drawings

Claims (11)

649856 1. Apparatus for authenticating documents, characterized in that it comprises: several elements (70, ZI9) sensitive to radiation; a source of radiation (64); means (28, 30, 34, 38) to position a document to be identified so that the radiation emitted by the source is directed to a part of the document then, from there, to said elements to encourage them to produce several output signals; means (7, 18, 82) for comparing the output signals of each element with the same predetermined threshold value in order to produce a counting signal indicating the number of elements activated up to this threshold value by the radiation emitted by said part of the document; means (84, fig. 12) for comparing the counting signal with a lower limit and an upper limit corresponding respectively to the minimum number and to the maximum number of elements to be activated up to the threshold value by an authentic document; and means (84) responsive to the comparison means, for indicating whether the document is authentic or not. 2. Apparatus according to claim 1, characterized in that the radiation is light radiation and that the elements are photosensitive elements. 2 3. Apparatus according to claim 2, characterized in that it comprises an inner conduit (14, 16) for receiving the document to be authenticated as well as means for moving it along the conduit. 4. Apparatus according to claim 3, characterized by a window (60) opening onto the conduit, the source of light radiation being arranged to illuminate the window. 5. Apparatus according to one of the preceding claims, characterized in that these elements are arranged so as to form a network. 6. Apparatus according to one of the preceding claims, characterized in that it comprises a first memory (Z5) for storing a first number corresponding to the minimum number of elements to be activated and a second memory (Z6) for storing a second number corresponding to the maximum number of elements to be activated, these numbers forming the lower and upper limits. 7. Apparatus according to claim 6 for authenticating two different types of documents, characterized in that it comprises a third and a fourth memory for storing a third respectively a fourth number corresponding to another minimum respectively maximum number of activated elements, that the comparison means are arranged to compare these last two numbers with the counting signal and that the means reacting to the comparison means indicate whether the document is an authentic document of one type or the other or if this n is not an authentic document. 8. Apparatus according to one of claims 6 or 7, characterized in that it comprises means for transmitting to the memories an information concerning the number of activated elements, means (122) for operating the apparatus in a mode learning where the transmission means are activated, means for controlling at least one memory associated with a minimum number so that it records the smallest number of activated elements after the positioning of several successive documents and for controlling at least a memory associated with a maximum number so that it stores the greatest number of activated elements after the positioning of several successive documents. 9. Apparatus according to one of the preceding claims, characterized in that it comprises detector means (52, 56) for determining the position of a document and means reacting to these detector means for examining the elements so as to provide the signal indicating the number of activated elements. 10. Apparatus according to claims 3 and 9, characterized in that the means reacting to the detector means periodically scan the elements during the movement of the document along the conduit to provide several counting signals and in that the comparison means are arranged to periodically compare these count signals with the lower and upper limits. 11. Apparatus according to one of the preceding claims, character-ized in that it comprises means for operating it in an authentication mode as well as means for operating it in a learning mode, the latter means comprising means responsive to the comparison means for updating the lower and upper limits when examining several successive authentic documents.