EP1160741A2

EP1160741A2 - Device for recognition of coins and the like

Info

Publication number: EP1160741A2
Application number: EP01109464A
Authority: EP
Inventors: Alessandro Ratti; Ezio Panzeri
Original assignee: Vesiel SpA
Current assignee: VESIEL S.P.A.
Priority date: 2000-05-04
Filing date: 2001-04-24
Publication date: 2001-12-05
Also published as: ITMI20000973A0; ITMI20000973A1; EP1160741A3; IT1317457B1

Abstract

A device for the recognition of coins and the like, comprising two parallel walls (2,3) which are arranged side by side so as to form a path for the passage of at least one coin, at least one of the walls having lighting means (5) which are adapted to illuminate the path of the at least one coin, the opposite wall being provided with optical sensor means (6) and with inductive sensor means (7) in order to determine respectively a sequence of measurements of chords of the at least one coin and a sequence of inductive measurements obtained from the coin.

Description

The present invention relates to a device for the recognition of coins and the like. More particularly, the invention relates to a device for the automatic recognition of the characteristics of coins and the like.
It is known that many fields of application require reliable automatic recognition of different types of coin in order to determine their value for the purpose of counting them, dispensing them on the part of a vending machine, or of providing a service such as a parking meter.
Several characteristic parameters can identify a coin: the main ones are its geometric dimensions, i.e., thickness, diameter, type and depth of coinage, edge size, reeding, and recently the determination of whether the coin is bimetallic or not.
Optical sensors or inductive sensors are currently used in order to determine the identifying parameters of a coin.
Optical sensors have the advantage of considerable precision and resolution, but are unable to provide information regarding the material of which the coin is made.
Since counterfeit coins are presumably made by producing coins whose dimensions and shape are fully identical to those of genuine coins, sometimes with the only difference of the material, which might not be the exact type used in genuine coins, the ability to determine the type of material is therefore essential in order to assuredly distinguish whether the coin is genuine or counterfeit.
The use of inductive sensors is a low-cost system not only for measuring the geometric parameters but also for determining the type of material of which the coin is made. The measurement of all inductive sensors in fact depends on the interaction between the field generated by the sensor and the eddy currents that the field generates in the material being measured. The intensity of these currents depends on the resistivity of the material and on the tested frequency.
By appropriately sizing the inductive sensors it is possible to achieve a high dependency on the type of material and a low dependency on geometric dimensions.
The interaction between the frequency and the material is very useful and allows to determine the electrical characteristics of the material of which the coin is made without having to make direct contact with said coin.
The aim of the present invention is to provide a device for the recognition of coins and the like which is capable of combining the characteristics of high precision and resolution that are typical of optical sensors with measurement characteristics that depend particularly on the type of material of the object to be measured, which are typical of inductive sensors.
Within this aim, an object of the present invention is to provide a device for the recognition of coins and the like which allows to determine assuredly the characteristics of so-called bimetallic coins.
Another object of the present invention is to provide a device for the recognition of coins and the like in which the determination of the type of material has a fundamental role in the recognition of the coin together with the geometric characteristics of said coin.
Another object of the present invention is to provide a device for the recognition of coins and the like which is highly reliable, relatively easy to manufacture and at competitive costs.
This aim and these and other objects which will become better apparent hereinafter are achieved by a device for the recognition of coins and the like, characterized in that it comprises two parallel walls which are arranged side by side so as to form a path for the passage of a coin, at least one of said walls having lighting means which are adapted to illuminate said path of said at least one coin, the opposite wall being provided with optical sensor means and with inductive sensor means in order to determine respectively a time sequence of measurements of chords of said at least one coin and a sequence of inductive measurements obtained from said coin which correspond to said measurements of chords of the coin.
This aim and these objects are also achieved by a method for the recognition of coins and the like, characterized in that it comprises the steps of:
passing a coin in front of sensor means, said sensor means comprising at least one optical sensor and at least one inductive sensor;
detecting, by means of said at least one optical sensor, a time sequence of chords of said coin;
detecting, by means of said at least one inductive sensor, a sequence of inductive measurements of said coin, which correspond to the measurements of the chords;
defining a curve of the inductive measurement as a function of said chord of the coin; and
comparing said defined curve with pre-stored curves related to different types of coin in order to determine whether the coin is genuine or counterfeit.
Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the device according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
Figure 1 is a schematic plan view of the recognition device according to the present invention;
Figure 2 is a schematic side elevation view of the device according to the present invention;
Figure 3 is a chart which plots the correlation between the inductive measurement and the chord of the coin, obtained by using the device according to the present invention; and
Figure 4 is a chart, similar to Figure 3, of the case of the recognition of a bimetallic coin.
With reference to the figures, the coin recognition device according to the present invention, generally designated by the reference numeral 1, comprises two parallel walls 2 and 3 which are spaced by a distance which is sufficient to form a path for the sliding of at least one coin 4, which slides in a vertical position which is parallel to the walls 2 and 3.
At least one of the walls 2 and 3 is provided with a lighting device 5 which is adapted to illuminate the coin 4 that slides between the walls 2 and 3 in order to determine its diameter optically.
At least one optical sensor 6 and at least one inductive sensor 7 are applied to the opposite wall, for example the wall 3, in a collinear arrangement; the optical sensor measures time sequences of chords of the coin 4 and the inductive sensor measures electrical characteristics thereof as the coin 4 passes in front of it.
Conveniently, the inductive sensor 7 has a much smaller diameter than the coin 4, so that it can determine the local electrical characteristics of the coin.
As the coin 4 slides in front of the optical sensor 6 and the inductive sensor 7, the pair of values of the chord and of the inductive measurement is acquired at regular time intervals.
These two values allow to define a curve of inductive measurements as a function of the measurement of the chord which is specifically correlated to the type of material and to the combination of materials of which the coin 4 is made.
For example, considering a monometallic coin, the chart of Figure 3 plots, on the Y-axis, the inductive measurement I_M as a function of the chord of the coin detected by the optical sensor 6.
The chart of Figure 3 defines three distinct regions on the X-axis (chord of the coin) which are designated by the reference letters A, B and C respectively.
The region A plots the entry of the coin between the walls 2 and 3 and is the region in which only the optical sensor 6 is affected, since the coin has not yet reached the inductive sensor 7.
The region B indicates the passage of the coin 4 in front of the inductive sensor 7 as well as in front of the optical sensor 6, and the inductive sensor interacts only with the edge of the coin.
Substantially, this is the condition in which the coin is partially in front of the optical sensor 6 and has entered the detection field of the inductive sensor 7.
Finally, the regions C illustrates the condition in which the coin 4 affects both the optical sensor 6 and the inductive sensor 7 and said inductive sensor interacts with the solid body of the coin 4.
Figure 4 illustrates a situation which is similar to Figure 3 in the case of a coin 4 of the bimetallic type.
As clearly shown, the chart of Figure 4 differs from the chart of Figure 3 in that the region B shown in Figure 3 is now divided into two regions B1 and B2 and substantially the region B corresponds to the region in which the coin 4 affects both the optical sensor 6 and the inductive sensor 7 but the inductive sensor interacts exclusively with the edge of the coin, which is made of a first material.
The region B2 illustrates instead the situation in which the coin 4 affects both the optical sensor 6 and the inductive sensor 7 but the inductive sensor interacts in the region of contact between the two different types of material of which the coin is made.
Correlation between the chord detected by the optical sensor 6 and the inductive measurement detected by the inductive sensor 7 allows to avoid using the region B2 to define the type of coin, since said region is too variable according to the contact resistances between the first material and the second material of which the coin 4 is made.
Finally, the region C designates the situation in which both the optical sensor 6 and the inductive sensor 7 are affected by the passage of the coin 4 and the inductive sensor 7 interacts with the solid body of the coin, which is made of the second material.
The relation between the chord of the coin and the inductive measurement depends on the geometric characteristics of the coin and on the materials of which it is made, and therefore constitutes a "signature" of said coin which is difficult to imitate.
Moreover, as noted earlier, in bimetallic coins the region of contact between the two metals that constitute the coin is too variable to be useful in the recognition of said coin. For this reason, the region B2 must be eliminated from the comparison criteria, since it might lead to a high likelihood of refusal of coins which are actually not counterfeit.
In practice it has been observed that the device and the method of use according to the invention fully achieve the intended aim and objects, since they allow to combine the best characteristics of optical sensors and inductive sensors so as to correlate the dimensional characteristics and the materials of coins and in particular to define a chord-inductive response curve so as to determine whether a coin is genuine or counterfeit.
The device thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may further be replaced with other technically equivalent elements.
In practice, the materials employed, so long as they are compatible with the specific use, as well as the dimensions, may be any according to requirements and to the state of the art.
The disclosures in Italian Patent Application No. MI2000A000973, from which this application claims priority, are incorporated herein by reference.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims

A device for the recognition of coins and the like, characterized in that it comprises two parallel walls which are arranged side by side so as to form a path for the passage of a coin, at least one of said walls having lighting means which are adapted to illuminate said path of said at least one coin, the opposite wall being provided with optical sensor means and with inductive sensor means in order to determine respectively a time sequence of measurements of chords of said at least one coin and a sequence of inductive measurements obtained from said coin which correspond to said measurements of chords of said coins.
The device according to claim 1, characterized in that said optical sensor means and said inductive sensor means are arranged in a collinear configuration.
The device according to claim 1, characterized in that said mutually parallel side-by-side spaced walls are made of plastics.
The device according to one or more of the preceding claims, characterized in that said optical sensor means comprise at least one optical sensor and said inductive sensor means comprise at least one inductive sensor.
The device according to claim 4, characterized in that said inductive sensor has a much smaller diameter than said at least one coin.
A method for the recognition of coins and the like, characterized in that it comprises the steps of:

passing at least one coin in front of sensor means, said sensor means comprising at least one optical sensor and at least one inductive sensor;

detecting, by means of said at least one optical sensor, a time sequence of chords of said coin;

detecting, by means of said at least one inductive sensor, a sequence of inductive measurements of said coin, which correspond to the measurements of the chords;

defining a curve of the inductive measurement as a function of said chord of the coin; and

comparing said defined curve with pre-stored curves related to different types of coin in order to determine whether the coin is genuine or counterfeit.
The method according to claim 6, characterized in that said curve of the inductive measurement as a function of the chord defines at least three regions:

a first region which determines the passage of said coin exclusively at said optical sensor;

a second region which determines the passage of the coin at the field of influence of said optical sensor and of said inductive sensor, said inductive sensor interacting only with the edge of said coin; and

a third region which defines the passage of said coin at the field of influence of said optical sensor and of said inductive sensor which interacts with the body of said coin.
The method according to claim 7, characterized in that for bimetallic coins said second region is divided into a first subregion and a second subregion, said first subregion indicating the interaction of said inductive sensor exclusively with the edge of said coin, made of a first material, said second subregion indicating the interaction of said inductive sensor with the region of contact between said first material and a second material of which said coin is made.