EP3699875B1 - Method and device for checking a coin - Google Patents

Description

In general, research is being conducted on methods that can be used to check coins or medals that have an embossed surface. It is important to reliably identify counterfeit coins. A particular challenge is the problem that counterfeit coins are often difficult to distinguish from worn coins by automatic methods.

A method for testing a surface of objects is from WO 2015/031922 A1 known. A device with a sensor for detecting coins is from EP 0 209 842 A2 known.

The object of the present invention is to provide an improved method for checking a coin or medal and an improved device for checking a coin or medal. Another object of the present invention is to provide an improved coin or medal.

According to the present invention, the object is solved by the subject matter and the method of the independent patent claims. Advantageous further developments are defined in the dependent patent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

• FIG. 1 zeigt eine schematische Querschnittsansicht einer Münze oder Medaille zur Veranschaulichung von Elementen des Verfahrens.
• FIG. 2A bis 2C veranschaulichen weitere Elemente einer Münze oder Medaille zur Erläuterung weiterer Verfahrensmerkmale.
• FIG. 3 fasst ein Verfahren gemäß Ausführungsformen zusammen.
• FIG. 4A bis 4C veranschaulichen das Verfahrensmerkmal der Erzeugung einer Messgröße, die einer Häufigkeitsverteilung entspricht.
• FIG. 5A bis 5C zeigen jeweils eine schematische Querschnittsansicht einer Münze gemäß Ausführungsformen.
• FIG. 6 zeigt eine schematische Querschnittsansicht eines Teils einer Münze gemäß weiteren Ausführungsformen.
• FIG. 7 zeigt eine Vorrichtung zur Überprüfung einer Münze.
• FIG. 8A und 8B veranschaulichen Querschnittsansichten von Münzen zur Erläuterung weiterer Verfahren zur Ermittlung einer horizontalen Referenzebene.

The accompanying drawings are provided for understanding of embodiments of the invention. The drawings illustrate Exemplary embodiments and together with the description serve to explain them. Further exemplary embodiments and numerous of the intended advantages result directly from the following detailed description. The elements and structures shown in the drawings are not essential shown to scale to each other. The same reference numbers refer to the same or corresponding elements and structures.

• FIG. 1 Figure 12 shows a schematic cross-sectional view of a coin or medal to illustrate elements of the method.
• FIG. 2A to 2C illustrate further elements of a coin or medal to explain further process features.
• FIG. 3 1 summarizes a method according to embodiments.
• FIG. 4A to 4C illustrate the process feature of generating a measured variable that corresponds to a frequency distribution.
• FIG. 5A to 5C 12 each show a schematic cross-sectional view of a coin according to embodiments.
• FIG. 6 12 shows a schematic cross-sectional view of part of a coin according to further embodiments.
• FIG. 7 shows a device for checking a coin.
• FIG. 8A and 8B illustrate cross-sectional views of coins to explain other methods of determining a horizontal reference plane.

DETAIL DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings which form a part of the disclosure, and in which, for purposes of illustration, specific Examples are shown. In this context, directional terminology such as "top", "bottom", "front", "back", "over", "on", "in front", "behind", "front", "back", etc. is referred to the Orientation related to the figures just described. Because the components of the exemplary embodiments can be positioned in different orientations, the directional terminology is used for purposes of explanation and is in no way limiting.

The description of the embodiments is not limiting, as other embodiments exist and structural or logical changes can be made without departing from the scope of the claims. In particular, elements of exemplary embodiments described below can be combined with elements of other exemplary embodiments described, unless the context dictates otherwise.

The term "vertical" as used in this description generally refers to the x-direction, as also in 1 shown.

The terms "lateral" and "horizontal" as used in this specification generally refer to a direction in the yz plane, as in 1 shown.

In the present description a method and a device for validating a coin or a medal are described. Furthermore, a coin or a medal is described. All descriptions of properties of a coin and the method are equally applicable to other coin-like elements or methods for checking coin-like elements, even if no explicit reference is made to these coin-like elements. Examples for more coin-like items include medals, tokens or tokens, and others. For reasons of simplicity, the application or the properties of a coin are essentially described. The coin or the coin-like element can each be made of metallic materials. They can also be made of or contain non-metallic materials, for example plastic materials.

Coins or coin-like elements have plastic elevations that protrude over three faces of a round, oval and/or disc of any angular shape. These elevations are called relief. This relief can be created, for example, by embossing the coin. However, according to other production methods for producing a coin, the relief can also be produced by casting, sintering or 3D printing. The relief is usually surrounded by what is known as the edge bar. This edge bar has a top edge that overlies and protects the relief.

To emboss coins, embossing dies are usually used which have a non-horizontal but curved surface in order to produce an optimal embossing. For example, depending on the mint, a different characteristic embossing die can be used, the surface of which is curved in a different manner in each case. The extent of this curvature is also referred to as crowning.

FIG. 1 1 shows a schematic cross-sectional view of a coin 10. The coin 10 has a relief 15 with a plurality of protruding areas. The relief 15 is surrounded by an edge bar 11 . As in FIG. 1 can be seen, the edge bar 11 extends to a greater height in the x-direction than the relief 15. When measuring the relief 15, the problem arises that that it is usually difficult to establish a reference plane for this measurement. More precisely, a coin base 14, ie a lowermost surface in relation to which the relief protrudes, can depend within the coin due to the embossing process on the crowning of the embossing die used. As in the lower part of the FIG. 1 shown, the coin base 14 does not run in a horizontal direction, ie parallel to the yz plane, but is concave due to the shape of the embossing die. The degree of concavity can depend on the crowning of the embossing die used, but also on other parameters.

As will be explained below, a method for inspecting a coin or medal according to embodiments includes determining a horizontal reference plane 101. A metric with respect to the horizontal reference plane 101 is then generated. A verification result is then determined from the measured variable.

In accordance with an example not in accordance with the invention, determining a horizontal reference plane may include determining an edge bar 11 of the coin 10 from a plurality of three-dimensional coordinates representing a surface of the coin. For example, the horizontal reference plane 101 can be determined from a final plane 102 of the edge bar.

According to an example not according to the invention, the final plane corresponds to that plane which almost completely touches the edge bar 11, ie lies flat on the edge bar 11 and corresponds, for example, to a horizontal extension of the flank head 12 of the edge bar.

The method may additionally include determining the plurality of three-dimensional coordinates. According to further embodiments However, these three-dimensional coordinates can also be determined by a separate device and used by the method according to the invention.

For example, the three-dimensional coordinates can be determined by general measuring methods for measuring a three-dimensional surface, for example non-contact measuring methods, for example optical measuring methods such as a laser triangulation method or a confocal measuring method or by tactile measuring methods such as scanning or profilometry. As a result, a plurality of three-dimensional coordinates each representing a surface of the coin are output.

The edge bar 11 is determined from the three-dimensional coordinates. The edge bar 11 usually extends to a greater height than the relief 15. Accordingly, the edge bar 11 can be determined by evaluating the maxima of the coordinates. A horizontal reference plane 101 can then be determined from the final plane 102 of the edge bar 11 . For example, the termination plane 102 can be determined by multiple regression from the three-dimensional coordinates of the edge bar points.

Further methods for determining the horizontal reference plane are described later with reference to the Figures 8A and 8B explained.

Then a measured variable in relation to the horizontal reference plane 101 is generated. For example, the distance between the raised parts of the relief 15 and the reference plane 101 can be determined. In this way, specific features of the coin 10 can be determined. These characteristics can be used to identify whether the coin is a counterfeit coin or not or if it's just worn out. The verification result ascertained from the measured variable can thus be “genuine” or “forged”, “worn (unfit)” or “fit for service”.

As mentioned, the reference plane 101 can be, for example, that plane which lies flat on the edge bar. As in FIG. 1 is further illustrated, a plurality of parallel planes 100 can be mentally arranged between the reference plane 101 and a base plane 105 and used to evaluate properties of the coin 10 . The base plane 105 corresponds, for example, to that plane which is shifted in the vertical direction with respect to the reference plane until it intersects a predetermined portion of the relief. For example, the predetermined proportion can correspond to 99% or another predefined value. As in FIG. 1 As illustrated, the ground plane 105 captures or intersects a large portion of the relief. The term "part of the relief" refers to the percentage of the area that is covered with coin material compared to the area that is not covered with coin material. In other words, the portion denotes an area portion where the x-coordinate of the three-dimensional coordinates is larger than the x-coordinate of the ground plane 105 .

Other terms used to describe the relief are explained below:
The edge head 12 of the edge bar corresponds to the maximum of the edge bar in the vertical, ie x-direction.

The foot of the flank 13 corresponds to the lowest part of a flank.

The height h denotes the displacement of the base plane 105 in relation to the reference plane 101.

The measurement plane corresponds to a plane that is vertically shifted with respect to the reference plane.

The relief is that volume which is created by lowering the measurement plane relative to the reference plane until the relief intersects a certain percentage, for example 99% or less, of the measurement plane.

The relief minimum corresponds to that height at which a predetermined percentage, for example 99%, of area coverage is reached when the measurement plane is lowered plane-parallel relative to the reference plane (deepest relief point).

The relief maximum is that height at which a predetermined percentage, for example 0.5% of the relief is recorded when the measurement plane is lowered plane-parallel with respect to the reference plane (highest relief point).

The relief height d corresponds to the difference between the relief maximum and the relief minimum. The relief height d can be determined in relation to the reference plane 101, for example.

A vertical safety area is usually provided with coins, which has no relief between the reference plane and the relief maximum.

The inner circle is the circle that lies within the set of all edge bar roots.

Because the reference plane is determined as the end plane of the edge bar, the measured variables can be determined in a reproducible and reliable manner. Accordingly, a reliable verification result is obtained. As a result is a quantifiable and reproducible assessment of the quality of newly issued or circulating coins or medals is possible.

The reproducibility of the measurement can thus be increased compared to conventional methods. In particular, the method is independent of, for example, the crowning of the stamps or properties of the coin materials. The method can also be carried out reliably if the coin base is not visible through the embossed image. In particular, according to the described embodiments, the evaluation method is independent of the coin resting firmly on a base, for example when determining the multiplicity of three-dimensional coordinates.

For example, the measured variable can be determined in relation to a base plane 105 that is shifted in the vertical direction with respect to the reference plane. In this case, the reference plane is shifted, for example, until a predetermined portion of the relief is recorded. For example, the predetermined proportion can be more than 98%, for example 99%. In this case, the measured variable can correspond to a volume of the relief above the displaced base plane 105, for example. This is in the FIG. 2A, 2B and 2C explained in more detail.

FIG. 2A 12 shows a cross-sectional view of the coin 10. The relief 15 can have a first embossed element 151 and a second embossed element 152, for example. The first embossed element 151 is in FIG. 2 B illustrated in more detail. As can be seen, a height of the surface of the first embossed element is 151×4 with respect to the ground plane 105. As in FIG FIG. 2C can be seen, the second embossed element rises up to different heights, for example x1, x2 and x3 with respect to the ground plane 105. From these values it can now be determine the volume of the first embossed element 151 and of the second embossed element 152 as a measured variable. This can be done in three dimensions, for example. According to further embodiments, this can also take place two-dimensionally in a predetermined cross-sectional plane. From the determined volume or the determined area as a measured variable, it can now be deduced whether the coin is counterfeit or genuine, worn or fit for circulation.

According to further embodiments, the respective volume can also be determined in relation to any measurement plane, which is shifted, for example, up to different vertical distances in relation to the reference plane 101 in each case. In this case, volume can be plotted against vertical distance, giving a metric.

According to further embodiments, the respective volume can also be determined in relation to any measurement plane that is shifted, for example, up to different degrees of area coverage of the relief in relation to the reference plane 101 . In this case, the volume can be plotted against the dot area, giving a metric.

Furthermore, the entire volume of the relief can be determined by this method, which can correspond, for example, to the volume of the plastic deformation of the embossing process. This variable can also be used, for example, to identify the degree of wear (unfit) of a valid coin or a forgery.

According to embodiments, for example, a height of the safety area can also be determined as a measured variable. The height of the safety area corresponds to the difference between the final plane of the edge bar, i.e. the reference plane 101 and the upper edge of the relief. The result of the check can correspond, for example, to fit/unfit, ie fit for circulation/worn out, or genuine/counterfeit.

FIG. 3 summarizes a method according to the invention. A method for inspecting a coin or medal includes determining (S110) a horizontal reference plane of the coin or medal, generating (S120) a metric relative to the horizontal reference plane, and determining (S130) a verification result from the metric.

Determining the horizontal reference plane may additionally include determining (100) an edge bar of the coin or medal from a plurality of three-dimensional coordinates representing a surface of the coin or medal, in an example not according to the invention. In this case, the horizontal reference plane corresponds to a finishing plane of the edge bar.

The Figures 4A to 4C describe a method for validating a coin according to further embodiments. The method is based on the comparison of an area occupancy as a function of a vertical position of a measurement plane with an area occupancy that was obtained from genuine and fit coins. Typically, the area occupancy may vary as a function of a vertical position of the measurement plane depending on the mint where the coin was minted. The height of the edge bar can also vary, depending on which blank manufacturer produced the associated blank (coin blank).

To carry out the method, a reference histogram of a real coin can first be determined. For this purpose, the area occupancy is dependent on a vertical position of the measurement plane for different measurement planes at different vertical positions of a genuine coin. For example, the previously described method, in which a reference plane is determined, can be used here. A reference histogram is determined as the result. This can be done, for example, as in Figure 4A look shown.

In Figure 4A the x-axis corresponds to the vertical position of the measuring plane, the y-axis corresponds to the percentage of area covered. In Figure 4A an area 400 is indicated as a hatched area, which results from a measurement on a large number of genuine and fit coins. The shaded area 400 thus corresponds to the scatter range or tolerance range of genuine circulation coins. Region 400 shows an area occupancy range as a function of vertical position. It must also be taken into account that the 0 point of the x-axis corresponds to the vertical position of the reference plane 101, ie the end plane of the edge bar. The first solid line 405 denotes a vertical position at which the area occupancy corresponds to a first predetermined value, for example 1%. The second solid line 406 designates a vertical position at which the area occupancy corresponds to a second predetermined value, for example 99%.

Furthermore, the area occupancy is determined as a function of a vertical position of a coin to be checked. An example of a measurement curve obtained is in Figure 4B labeled 415. In Figure 4B again the first and second solid lines 405, 406 of the genuine coin are indicated. Also shown is the land occupancy area 400 of the genuine coin. As can be seen, both a first and a second vertical position (represented by lines 407, 408) at which the area occupancy corresponds to the first and second predetermined value, respectively, are dependent on the associated first and second vertical position (represented by lines 405, 406) of the genuine coin. Furthermore, the function 415, which gives the area occupancy as a function of the vertical position, has a different slope than the area occupancy range 400 of the real coin.

Figure 4C shows a further measurement curve 415 in comparison with an area occupancy area 400 of real coins. In Figure 4C the first and second solid lines 405, 406 of the genuine coin are also indicated. As can be seen, the second vertical position (represented by line 408) at which the area occupancy corresponds to the second predetermined value is different from the associated second vertical position (represented by line 406) of the genuine coin. Furthermore, the function 415, which reports area occupancy as a function of vertical position, intersects the area occupancy area 400 of the genuine coin in some places and extends outside the area occupancy area 400 of the genuine coin in other places. Correspondingly, the function 415 has, at least in sections, a different slope than the area occupancy area 400 of the genuine coin.

FIG. 5A shows a cross-sectional view through a coin 10 with a first embossed security element or relief 153. FIG. 5A 11 further illustrates the coin's edge bar 11, the edge head of the edge bar and a reference plane 101. The in FIG. 5A The first relief-like security element 153 also shown has a surface that does not run parallel to the horizontal reference plane. Rather, for example, the surface of the first embossed security element 153 can be formed in a convex shape. According to further embodiments, the surface of the first embossed security element 153 can have convex and concave areas.

As in FIG. 5B As shown, the second embossed security element 154 may have a concave surface. The in the FIG. 5A and 5B The coin shown thus contains a relief which has a surface which is not parallel to a reference plane of the coin. In this case, the reference plane 101 corresponds to that plane which lies flat on the edge bar and forms the final plane of the edge bar 11 .

According to further embodiments, the coin may have a first embossed security element 153 and a second embossed security element 154 . For example, the first embossed security element 153 can have a convex surface area. The second embossed security element 154 may have a concave surface area. In this way, for example, the histogram, i.e. the area coverage depending on the vertical position of the reference plane, can have a characteristic shape. The characteristic shape of the histogram is not easily recognizable from the outside.

As shown, the embossing profile and in particular the histogram can be made characteristic of the examination method described. For example, the security elements can have a characteristic surface profile. This characteristic surface profile can be determined or verified using the method described for checking. In this way, a security feature that is not visually recognizable to the viewer can be used to determine whether the coin is genuine or counterfeit. If, for example, a characteristic surface profile is used that has a characteristic histogram, the authenticity of a coin can be checked in a simple manner. For example, a characteristic histogram may have levels at certain Points where the area occupancy increases sharply.

According to further embodiments, the edge bar 11 of the coin can have a characteristic profile, such as in FIG FIG. 6 is illustrated. FIG. 6 Figure 12 shows a cross-sectional view through a coin where the edge bar has a special shape. In particular, the edge bar flank 11a is stepped. Two steps 111, 112, for example, are formed in the edge bar flank along a vertical direction. The step 111 is formed at the height h1, and the step 112 is formed at the height h2, with h1 and h2 each being measured with respect to the reference plane 101. The height h3 corresponds to the height h of the edge bar 11. There can be any number of steps 111. Furthermore, the step can each at least partially have a horizontal or non-horizontal, for example concave or convex surface. According to other embodiments, the step may have a planar or level but non-horizontal surface area. The height profile of the edge bar 12 can be determined or verified by the method described for checking a coin. In this way, it can be determined whether the coin is genuine or counterfeit using a security feature that is not visually recognizable to the viewer.

In addition, corresponding height profile sections can extend in a circle along the edge bar and can be segmented. In this way they can represent a kind of coding or barcode. This coding can be evaluated as a further security feature.

According to further embodiments, the security features described can be combined with one another. Furthermore similar steps can also be provided on side flanks of the relief.

FIG. 7 12 shows an apparatus 20 for validating a coin or medal 10 according to embodiments. The device 20 comprises a device 22 for determining a horizontal reference plane 101, a device 23 for generating a measured variable in relation to the horizontal reference plane 101, and a device 24 for determining a verification result from the measured variable. For example, the device 20 can additionally include a measuring device 25 for detecting the plurality of three-dimensional coordinates. As explained above, this measuring device 25 can be suitable for carrying out a measuring method for measuring a three-dimensional surface. The device 22 for determining a horizontal reference plane can, for example, comprise a device 21 for determining an edge bar 11 of the coin 10 from a large number of three-dimensional coordinates which represent a surface of the coin 10 . In an example not according to the invention, the horizontal reference plane can correspond to a termination plane of the edge bar 11 . The device 20 can also include a display device 26 for visualizing, for example, the ascertained verification result or the measured variable. According to further refinements, the check result can also be transmitted to a further device.

Figure 8A 12 illustrates a cross-sectional view of a coin 10 to explain other methods of determining a horizontal reference plane 101. According to examples not in accordance with the invention, the horizontal reference plane 101 can be determined from a termination plane 102 of the edge bar 11. FIG. For example, the horizontal reference plane 101 of the upper or lower end level 102, 103 of the edge bar 11 correspond. According to further examples not according to the invention, the horizontal reference plane can also be off an averaging over the upper and lower end level 102, 103 of the edge bar 11 can be determined.

Figure 8B 12 illustrates a cross-sectional view of a coin 10 for explaining methods for determining a horizontal reference plane 101 according to further embodiments. As in Figure 8B is shown, the horizontal reference plane 101 is determined according to the invention from a final plane 104 of a relief 151 . The method thus includes determining a termination plane 104 of a relief 151. For example, the relief 151 can have a horizontal surface. According to further embodiments, the relief 151 can also have a concave surface, such as in FIG Figure 5B is shown. In this case, for example, a final plane can be defined over the edge or maxima of the relief 151. For example, when the checking method is carried out, it is known how precisely the reliefs 151 are configured. Therefore, the procedure can be adjusted accordingly.

According to further embodiments, the determination of the horizontal reference plane 101 can include the determination of a vertical boundary 106 of the coin. The horizontal reference plane 101 can then run perpendicularly to the vertical boundary 106 . According to further embodiments, the determination of the horizontal reference plane 101 can include the determination of a bearing surface 108 of the coin 10 . For example, the coin may rest on a conveyor belt or other support surface 108 when the method is performed. The surface of the conveyor belt or the other support surface 108 can then correspond to the horizontal reference plane 101 .

Although specific embodiments have been illustrated and described herein, those skilled in the art will appreciate that A variety of alternative and/or equivalent configurations may be substituted for the specific embodiments shown and described without departing from the scope of the invention. The application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is only to be limited by the claims.

Claims (12)

1. Method for checking a coin (10) or a medal or medallion, comprising

   determining (S110) of a horizontal reference plane (101) of the coin or medallion or medal, wherein the determining of the horizontal reference plane (101) comprises the determining of a termination plane (104) of a relief (151, 152) of the coin (10), and the horizontal reference plane (101) is determined from the termination plane (104) of the relief (151, 152) of the coin;

   producing (S120) a measured value in relation to the horizontal reference plane (101); and

   determining (S130) of an examination result from the measured value.
2. Method according to claim 1, wherein the measured value is determined in relation to a plane which is displaced in the vertical direction in relation to the reference plane (101), wherein the plane is displaced so far until the plane intersects a predetermined portion of a relief of the coin.
3. Method according to claim 2, wherein the plane displaced in the vertical direction in relation to the reference plane (101) is a base plane, and the predetermined portion is greater than 90%.
4. Method according to claim 2 or 3, wherein the measured value corresponds to a three-dimensional volume of the relief above the displaced plane.
5. Method according to claim 2 or 3, wherein the measured value corresponds to a two-dimensional area of the relief above the displaced plane in a specific vertical sectional plane.
6. Method according to claim 1, wherein the measured value corresponds to a surface allocation as a dependency of a vertical position of a measured plane at different vertical positions of the measured plane.
7. Method according to claim 6, wherein the determining of the examination result comprises a comparison of the measured curve with a reference histogram of a genuine coin, wherein the reference histogram is a superimposition of measured curves on different genuine coins.
8. Method according to claim 7, wherein the comparison of the measured curve comprises the evaluation of a first position and the evaluation of a second position, wherein the first position corresponds in each case to a surface allocation with a first predetermined limit value, and the second position corresponds in each case to a surface allocation with a second predetermined limit value.
9. Method according to claim 7 or 8, wherein the comparison of the measured curves comprises a comparison of a rise in the measured curve with the rise of the reference histogram.
10. Method according to any one of claims 7 to 9, wherein the comparison comprises the examination as to whether the measured curve intersects the histogram.
11. Apparatus (20) for checking a coin or medallion or medal (10), comprising

    a device (22) for determining a horizontal reference plane (101) of the coin or medallion or medal (10);

    a device (23) for producing a measured value in relation to the horizontal reference plane (101); and

    a device (24) for determining an examination result from the measured value, wherein the device (22) for determining a horizontal reference plane (101) comprises a device (21) for determining a termination plane (104) of a relief (151, 152) of the coin (10), and the device (22) for determining the horizontal reference plane (101) is configured to determine the horizontal reference plane (101) from the termination plane (104) of the relief (151, 152) of the coin.
12. Computer program product, comprising commands which have the effect of the device according to claim 11 carrying out the method steps according to claim 1.

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