EP1287496A1

EP1287496A1 - Device for verifying documents

Info

Publication number: EP1287496A1
Application number: EP01940526A
Authority: EP
Inventors: Robert Massen; Thomas Franz; Thomas Leitner; Jörg EBERHARDT
Original assignee: Bundesdruckerei GmbH
Current assignee: Bundesdruckerei GmbH
Priority date: 2000-06-07
Filing date: 2001-05-25
Publication date: 2003-03-05
Anticipated expiration: 2021-05-25
Also published as: DE50114972D1; PL359020A1; PL204284B1; ATE436061T1; HUP0300799A2; CA2411689C; CN1430770A; US20030156274A1; CA2411689A1; CN1191554C; HU227013B1; US6892946B2; DE10028241A1; WO2001095261A1; EP1287496B1

Abstract

The invention relates to a device for automatically verifying valuable documents and security documents. The device has a cross slide which is displaceable in the X-Y direction and on which the components that are required for evaluating the authenticity features are located. The X slide of the cross slide which is displaceable in the X direction is displaceably arranged inside an outer, Y slide which is displaceable in the Y direction. A first group of evaluating units for evaluating diffraction structures is located on the X slide with a laser and an optical evaluation system, while a second group of evaluating components, e.g. for evaluating a text, an IR field and/or a photo field, is located on the Y slide. A UV illumination source can also be provided for testing the fluorescence features of a document, and is evaluated by a separate, stationary evaluation unit or by the evaluation unit on the X slide. The inventive document verification device enables a document to be automatically examined rapidly and accurately with respect to its authenticity features and i.a. even authenticity features with diffraction structures can be identified reliably and efficiently.

Description

Dokumentenprufgerat

The invention relates to a document checking device according to the preamble of claim 1. Document checking devices of this type have become known in multiple embodiments. They are used to automatically check the authenticity of documents, in particular passport cards, ID cards, driver's licenses, identity cards, residence certificates (visas) and the like. B. also drop tickets.

The invention therefore relates to the automatic checking (verification) of documents of any kind which are provided with certain authenticity features. It is known here to place the document to be checked on a transparent support surface, to illuminate the document from below with appropriate illumination sources and to record the reflected image with a camera. In a manner known per se, these are one or more matrix cameras which record the illuminated ID or document image and with one evaluate downstream software. However, the evaluation resolution of such a fixed unit is severely limited because, for example, known cameras have a resolution of 600 dpi and, because of the mirror deflection and the document size, only an evaluation accuracy of 100 dpi is possible with conventional identity cards or pass cards.

That is, that is, the known document evaluation devices have a relatively low resolution and therefore a relatively poor possibility of recognizing the authenticity features on the documents.

Such document checking devices are indeed suitable for reading text from the document - as is also known for flatbed scanners - but they are not suitable, e.g. B. read out a 2D barcode or not at all suitable to read out corresponding authenticity features which are based on diffraction structures or which relate to authenticity features hidden in image parts by steganography.

The resolving power of such known arrangements is insufficient.

So far, it has only been known to read authenticity features that are based on diffraction structures with a separate laser device, a laser and an associated evaluation unit being arranged in a hand-held device and the entire device being manually checked for the corresponding authenticity feature on the document that is recognized by the eye is placed, in order to then cause this handheld device to read out the authenticity feature and to evaluate the authenticity feature.

However, it is not known to use such an evaluation unit in an automatically working document checking device.

There are also known in the general field of the prior art flatbed scanners which essentially consist of a carriage which can be moved in the Y direction and on which carriage an illumination unit is arranged and further a camera which detects and evaluates the image generated by the illuminated document. However, such flatbed scanners are not suitable for automatic document checking because they are not suitable for recognizing authenticity features on the basis of diffraction structures in a document. This includes an evaluation with a laser beam.

In addition, flatbed scanners are not suitable for recognizing special structures on a document, because it is necessary to illuminate such special structures with different illumination sources.

The invention is therefore based on the object of developing a document checking device of the type mentioned in such a way that an automatic examination of a document for authenticity features is possible quickly and accurately, with u. a. Authenticity features with diffraction structures should also be recognized reliably and correctly.

To achieve the object, the invention is characterized by the technical teaching of claim 1.

An essential feature of the invention is that the document checking device has a cross slide that can be moved in the X-Y direction, the components required for evaluating the authenticity features being arranged on this cross slide (hereinafter also referred to as X-Ϋ slide).

With the given technical teaching there is the essential advantage that an X-Y slide is now used, on which the components necessary for evaluating the authenticity features are arranged.

There is thus the advantage that such an X-Y carriage can be used to approach the authenticity features of the document to be examined with high precision and the verification thereof on the spot

Authenticity features with the highest resolution and highest recognition accuracy can perform. As a result of this XY positioning possibility of the evaluation unit, it is consequently also possible to compensate for position errors of the authenticity features on the document. Namely, a document has been produced in such a way that the authenticity feature on the document z. B. is shifted by several millimeters, then this can be recognized due to the structure of the XY carriage, because the carriage is positioned so that the evaluation unit is positioned exactly under this authenticity feature.

In a preferred embodiment of the invention, it is provided that the evaluation components are arranged on the X-Y slide, which are used to evaluate the diffraction structures and which are also used to evaluate other authenticity features, such as, for. B. a text, a barcode, a visible in the IR range or other authenticity features.

It is preferred here if the evaluation unit for evaluating the diffraction structures consists of a laser and a corresponding evaluation optics, the entire evaluation unit being arranged on an inner slide which can be moved in the XY direction, this inner slide (also referred to below as an X slide). is arranged to be movable in an outer carriage which is movable in the Y direction.

Such evaluation optics include in particular an OCR camera with a lens, which can read out certain document structures both in white light and in IR light.

It is now possible for the first time that the entire evaluation unit, consisting of a laser unit and the associated evaluation optics, can be moved in the X-Y direction and can thus be positioned very precisely under the authenticity features of the document to be examined.

You could also arrange the other evaluation components (for evaluating the text, IR field and photo field) on the inner X-slide, this however, it is not necessary for a solution. It is therefore preferred if the other evaluation components are arranged on the Y slide and are fixedly attached to the Y slide, so that they can only be moved in the Y direction, but not in the X direction.

This has the advantage that these components are not moved in the X carriage and therefore can only scan the document very precisely when viewed over the entire width of the document with the Y carriage and can scan the document across the entire width in a single operation. It is therefore a line-by-line scanning of the document in the Y direction.

In a further development of the invention, it is preferred if the lighting unit is also arranged on the Y-slide. This is not absolutely necessary for a solution, because a lighting unit (or even several lighting units) could also be arranged in a stationary manner outside the X-Y slide, so that the document can also be illuminated through the support surface. However, it is preferred if this lighting unit is arranged on the Y-carriage and consists of at least one lighting line, so that during the movement of the Y-carriage along the document along the lighting line, a light line (scanning line) on the document over the entire width of the document is generated and this scanning line is directed to the OCR matrix camera via appropriate mirror optics and is evaluated by the latter.

In a further development of the invention it is provided that a stationary evaluation unit for fluorescence features of the document is additionally arranged on the document checking device.

For this purpose, in a first embodiment, a stationary camera is mounted in the housing of the device, which looks at a mirror, which mirror in turn depicts the support surface - on which the document rests. The contact surface is now illuminated in the UV range with a suitable UV illumination source, so that the security elements of the document which are excited to fluoresce emit light and this is directed via the mirror onto the stationary matrix camera.

This evaluation unit is completely independent of the X-Y carriage, and separate protection - regardless of the other features of the invention - is claimed for this evaluation unit and its fixed arrangement and for the design of the details.

In another embodiment of this evaluation unit, it can be provided that the stationary UV camera is omitted and that instead the camera used for laser evaluation on the X-slide is used at the same time to also evaluate the UV image.

Of course, two separate cameras could also be mounted on the X-slide, one of which is suitable for laser evaluation of the diffraction structures, while the other camera is intended for evaluating the UV image.

Of course, the invention is not limited to the previously mentioned evaluation in the UV range; this depends in particular on the type of filter used and the type of lighting source used. Of course, all evaluations can also take place in a different spectral range, in particular polarization filters can also be used instead of the UV filters, or completely different wavelength ranges can be used.

In particular, the wavelength range of the NIR can be used (near infrared range) or any other wavelength range. To the extent that the following description speaks of a UV evaluation, this is only to be understood as an exemplary embodiment. All in all, it can be stated that the solution shown here of using an XY slide with a laser evaluation unit mounted in the X slide has the essential advantage that this laser unit is outstandingly protected against misalignment.

It would be conceivable to arrange a stationary laser which shines on an opposite mirror, the reflection of which is in turn recorded by an evaluation unit which is arranged to be movable in a carriage. However, this has the disadvantage that the stationary laser and the mirror arranged opposite have extraordinarily large beam lengths between them, so that the entire arrangement is very sensitive to misalignment. Such a device is sensitive to shock loads and would be misaligned in the event of such shocks and is very difficult to set.

This is where the invention comes in, which arranges the entire evaluation unit of laser, mirror and associated camera with lens in a confined space in an (inner) carriage which can be moved in the XY direction, as a result of which the entire unit is protected against impacts because only very short beam lengths between the laser unit and the evaluation unit must be replaced.

During transport, the entire X-Y slide can be very easily secured (locked), which means that the guides in which the X-Y slide is guided are protected accordingly and are secured against knocking out.

The invention also relates to the kinematic reversal of an XY slide. It has been explained above that the slide which can be moved in the X direction is the inner slide and the slide which is movable in the Y direction is the outer slide which, seen in the longitudinal axis of the device, can be moved along the document. In kinematic reversal it can also be provided that the inner slide can be moved in the Y direction and the outer slide in the X direction. Of course, the aforementioned XY slide or the YX slide can also be replaced by other position systems that can be positioned on two levels. It is therefore provided that the entire evaluation components can be moved freely in two perpendicular directions in space. This can be done by spindle drives, by electromotive drives or by electromagnetic drives.

Such systems, which can be freely positioned in the X-Y plane, are known. They consist of hydraulic or pneumatic cylinders, spindles driven by an electric motor or the like.

The subject matter of the present invention results not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another.

All of the information and features disclosed in the documents, including the summary, in particular the spatial design shown in the drawings are claimed to be essential to the invention, insofar as they are new to the prior art, individually or in combination.

The invention is explained in more detail below with the aid of drawings which illustrate only one embodiment. Here, further features and advantages of the invention are evident from the drawings and their description.

Show it:

Figure 1: Schematic of a section through the document checking device according to the invention;

FIG. 2: perspective side view of part of the laser evaluation unit; Figure 3: Section through the device showing further details;

Figure 4: a separate representation of the X-carriage with its drive;

Figure 5 is a side view of the Y-carriage;

Figure 6: a plan view of the device of Figure 3 with the X-carriage in two different positions.

In Figure 1, the housing 1 of a device is generally shown, which is approximately desk-like and has a front plate 2 inclined at an angle 4 to the horizontal, within which a transparent support surface 3 (z. B. made of glass) is arranged. The document to be examined is placed and pressed onto this contact surface 3 with a defined contact pressure, so that the document surface to be examined is visible from the underside of the contact surface 3.

According to the invention, an XY slide 7, 8 is now arranged in the housing 1 in slide guides to be described later, the Y slide 7 being movable in the Y arrow direction 5 and the X slide in the arrow direction 6 (namely perpendicular to the plane of the drawing in FIG. 1) ).

It is now important that the less sensitive evaluation components are arranged on the outer Y-carriage 7, namely in particular a lighting unit 14 which is inclined in an oblique direction to the plane of the front plate and which is preceded by a cell-shaped focusing lens 15, so that this is also in front of the row trained lighting unit 14 is emitted light via the focusing lens 15 on the lying on the support surface 3, document underside.

It is preferred if the lighting unit 14 (see FIG. 6 in this regard) consists of LEDs arranged in rows, which in particular generate white light. However, other lighting units can also be used, such as. Legs Illumination unit, which alternately provides LEDs, of which one part of the LEDs emits white light and the other an IR light.

Likewise, of course, a plurality of lighting units 14 can also be arranged side by side or also one above the other and each lighting unit can generate a separate spectrum or a mixed spectrum.

The light reflected by the illumination unit on the underside of the document is directed via the beam path 13 to a deflecting mirror 12 and is directed there by a lens 11 to a line camera 10 which is suitable for evaluating the text on the document accordingly or also image information or also hidden Information that can only be read out, for example, in the NIR area.

On the Y-carriage 7, a signal processing board 9 is also firmly attached, with the aid of which the corresponding evaluations are carried out. This ensures that the information paths and the cable lengths are short and therefore the entire arrangement is less prone to failure.

By comparing Figure 1 with Figure 3 it can be seen that the direction of the beam path 16 can be quite different, i. That is, in FIG. 1, the beam path 16 is inclined obliquely forwards in the direction of the support surface 3, while in FIG. 3 the beam path 16 is inclined obliquely backwards. Both inclined beam paths are claimed in the present invention.

The arrangement of an inclined beam path 16 at an angle to the support surface 3 has the advantage that with this lighting unit 14 and ultimately with the camera 10, initially roughly during the scanning of the document, the corresponding positions of the diffraction features to be detected later on with the laser evaluation unit are determined on the document can be. Thus, with the line camera 10 when scanning the document surface, the position of the diffraction features to be recognized later with the laser optics becomes rough determined and only later verified this diffraction feature with the laser evaluation components arranged on the X-slide.

It is important that the actual verification of the diffraction feature is carried out with the aid of the components arranged on the X-slide 8. These components consist of a laser 21 (see also FIG. 2), which generates a beam path 22 on a deflecting mirror 20, which in turn directs a beam path 23 onto the document surface to be examined.

It is assumed here that the X-Y slide 7, 8 is now positioned exactly below the diffraction feature to be examined, i. that is, the X-Y slide has already been moved to a precisely defined X-Y position. 1 shows only the basic position, while in the evaluation position the X-Y slide is moved at a very precisely defined location below the bearing surface 3 and suitable for evaluating the diffraction feature.

The reflected image generated by the diffraction feature is reflected on the focusing screen 19 and forms a specific diffraction pattern 49 on the focusing screen 19, which is viewed through the focusing screen 19 from below at a certain solid angle 24 of a QCR matrix camera 17 through an objective 18 becomes.

That is, that is, the diffraction pattern 49 striking the focusing screen is focused in the objective 18 and directed onto the OCR matrix camera 17 and evaluated there.

It is thus clear that the entire evaluation unit is arranged in the X-slide 8 in a confined space and insensitive to misalignment and therefore forms a very compact unit.

The UV evaluation unit, which is used in particular for evaluating fluorescent authenticity features on the document surface, will now be described. The entire arrangement is especially designed for viewing in UV light. This means that a UV flash 26 is provided for this purpose, which is provided with a filter plate 27, which directs a light with a high UV component onto the document surface in the direction of arrow 30 and thereby excites the document surface with characteristic fluorescent threads. The light reflected by the document 3 is directed between the limiting beam paths 32, 33 onto the mirror 25 and from there via the lens 28 with the image 31 into the camera 29 and recorded by a CCD chip arranged there.

A UV filter, which blocks the UV light, can be arranged in front of the lens 28, so that only a light outside the UV range is detected by the camera. As a result, the camera 29 cannot be “blinded” by the UV flash 26.

The mechanical components of the arrangement are now described in more detail with reference to FIGS. 3 to 6.

It is important here that, according to FIGS. 3 and 6, two guide rails 35 pointing in the Y direction are arranged parallel to one another and are firmly anchored in the housing 1. The guide rails 35 are each carried by bearing blocks 39.

In each of the guide rails 35 there are two ball bushings 48 arranged one behind the other (see FIG. 6), with which the Y-slide 7 is firmly connected.

The entire Y slide can thus be moved and controlled freely in the arrow directions 5 in the Y direction. The drive takes place via a stepper motor 34, which is firmly anchored to the housing 1 and which carries a toothed belt 37 via a drive shaft 36, which runs on a guide roller 40 on the opposite side. One strand of the toothed belt is connected to the Y slide 7. Of course it is. Not invention _. limited to an overhead guide with overhead, parallel guide rails 35; others can

Guide elements are used, especially those below

Guide rails 35, and instead of the four guide bushes 48 used, more or fewer guide bushes can also be used.

Furthermore, all linear guides which are capable of realizing such an X-Y slide 7, 8 are claimed.

On the underside of the Y _τ carriage 7, a housing 38 is arranged, in which the line camera 10 and the lens 11 are fixed, which ensures that these parts are easily interchangeable and can therefore be adjusted separately. In other words, due to the arrangement in the housing 38, the camera 10 can be adjusted very precisely at the factory to the lens 11 arranged there, and later the entire housing 38 can be adjusted very precisely to the deflection mirror 12 arranged outside.

The X slide 8 is arranged to be movable in the Y slide perpendicular to the plane of the drawing in FIG. 3.

Here, the X-slide 8 is driven to be displaceable on a left-hand guide designed as a pipe guide 41 so as to be displaceable to the plane of the drawing in FIG. 3, while the right-hand side of the guide is formed by a slide guide 50 on which the Y-slide only rests with a sliding block and Guide rail is firmly attached in the Y-slide.

To set the end position of the X-slide 8 in the Y-slide 7, two spaced-apart limit switches 42 are provided, which are also shown in FIGS. 4 and 5.

The X and Y axes each have two limit switches. The drive motor 43 for the X slide is fastened in the Y slide 7 and drives the X slide 8 in the direction of the arrow 6 via its drive shaft 44 and a toothed belt 45.

Here, this toothed belt 45 runs over a deflection roller 47 according to FIG. 5 in the Y slide 7.

The pipe guide 41 is otherwise attached to two spaced-apart bearing blocks 46 in the Y-slide according to FIG. 5.

FIG. 6 shows in plan view that the X-slide 8 can be moved into two different end positions, the end position of the X-slide being indicated at 8 '.

Zeichnunqsleqende

Housing 26 UV flash front panel 30 27 filter disk support surface 28 lens angle 29 matrix camera Y direction 30 arrow direction X direction 31 illustration Y slide 35 32 beam path X slide 33 beam path signal processing board 34 stepper motor line camera 35 guide rail lens 36 drive shaft deflection mirror 40 37 Timing belt beam path 38 Housing lighting unit 39 Bearing bracket (Y) focusing lens 40 Deflection roller beam path (lighting) 41 Pipe guide OCR matrix camera 45 42 Limit switch lens 43 Motor (X) focusing screen 44 Drive shaft deflection mirror 45 Timing belt laser 46 Bearing block (X) beam path 50 47 Deflection roller (X) Beam path .48 Ball bushing (Y) Solid angle 49 Diffraction pattern Deflection mirror 50 Slideway

Claims

claims

1. Document checking device for automatic checking of value and security documents, characterized in that the document checking device has a cross slide (7, 8) which can be moved in the XY direction (5, 6), the components (9-12, 14-21) are arranged on this cross slide (7, 8).

Document checking device according to claim 1, characterized in that the X-slide (8) of the cross slide, which can be moved in the X-direction (6), is arranged so as to be movable within an outer Y-slide (7) which can be moved in the Y-direction (5).

3. Document checking device according to one of claims 1 or 2, characterized in that a first group of evaluation units (17-21) for evaluating the diffraction structures on the inner in the X-direction (6) movable X-slide (8) of the cross slide (7th , 8) and is therefore movable in the X direction (6), as well as in the Y direction (5), and a second one

Group of evaluation components (9-12, 14, 15), for example for evaluating a text, IR field and / or a photo field, on the Y slide (7) of the cross slide (7, 8) which can be moved in the Y direction (5) ) is arranged, and therefore can not be moved in the X direction.

4. Document checking device according to claim 3, characterized in that this first group of evaluation units for evaluating the diffraction structures includes a laser (21) and a corresponding evaluation optics (17-20). Document checking device according to claim 4, characterized in that the

Evaluation optics (17-20) following the beam path of the laser (21) includes an evaluation mirror (20), a focusing screen (19), an objective (18) and an OCR matrix camera (17).

6. Document checking device according to claim 5, characterized in that the OCR matrix camera (17) can read both in white light and in IR light.

7. Document checking device according to one of claims 1 to 6, characterized in that on the Y-carriage (7) also the lighting unit (14) is arranged, which consists of at least one illumination line.

8. Document inspection device according to one of claims 1 to 7, characterized in that a stationary evaluation unit (25-29) for fluorescent features of a document is arranged on the document inspection device, which includes a stationary camera (29) in the housing (1) of the device, which looks at a mirror (25), which mirror (25) the

Plays the support surface (3) for a document, the support surface (3) being irradiated with a suitable UV illumination source (26), so that the emitted light of the document is directed via the mirror (25) onto the stationary camera (28).

9. Document checking device according to one of claims 1 to 7, characterized in that a suitable UV illumination source (26) is provided, which irradiates the support surface (3) and the emitted light of the document via the OCR matrix camera (17) or a separate one on the Y-

Carriage (7) attached camera is read, which UV radiation can read.

10. Document checking device for automatic checking of value and security documents, characterized in that a stationary evaluation unit (25-29) for fluprescence features of a document is arranged on the document checking device.

11. Document checking device according to claim 10, characterized in that the fixed evaluation unit (25-29) for fluorescent features of a document contains a fixed camera (29) in the housing (1) of the device, which looks at a mirror (25), which mirror ( 25) the bearing surface (3) for a

Images the document, the support surface (3) being irradiated with a suitable UV illumination source (26), so that the emitted light of the document is directed via the mirror (25) onto the stationary camera (28).