Classifications

• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
  • G07D5/005—Testing the surface pattern, e.g. relief
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
  • G07D5/02—Testing the dimensions, e.g. thickness, diameter; Testing the deformation
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D5/00—Testing specially adapted to determine the identity or genuineness of coins, e.g. for segregating coins which are unacceptable or alien to a currency
  • G07D5/10—Testing the rim, e.g. the milling of the rim

Definitions

• the invention relates to a method and a device for checking coins, in which the image of the coin is captured with an image sensor.
• time areas are to be examined, namely the entry of the coin into the sensor area, the exposure / exposure time, the data transfer or transfer for image processing in an evaluation device and image processing, analysis and evaluation. While there is no fixed time measure for the fourth time period, except for the maximum time of the overall process, the first three time periods are extremely time-critical.
• Run-in times of selected coins were determined, the run-in time being defined here from the immersion of the coin edge in the receiving area of the image sensor to the full detection of the coin by this receiving area.
• the measured run-in time was between 4.5 and 9.9 ms and that of 0.01, 0.10, 1 and 2 euro coins was 4/9; 5.9; 6.99 and 7.71 ms.
• the target diameter range of the coins to be measured is between 15 mm and 33 mm. Measurements in real coin validators showed a maximum coin speed of 3 m / s. Given the time, it is inconceivable to track the coin run to the correct position of the receptacle by cyclically scanning the image. In addition, in such a case, the data transmission times from the image processors to be processed are much too long.
• the invention has for its object to provide a method and an apparatus for checking coins with an image sensor for recording an image of the coin to be checked, in which the time of taking the image of the coin or the location of the recording is reliably determined and with which the data transmission times from the image sensor to the evaluation device are minimized.
• the property of image sensors is used that only partial areas can be read out. Since the scanning speed of the individual pixels is independent of their number, the transmission time can be assumed to be almost proportional to the number of points to be read out.
• the diameter of the coin By detecting the apex of the coin through the at least one column in the front in the direction of movement, the diameter of the coin can be determined, via which information about the height and width of the overlap area can be made.
• the speed of the coin can be calculated in a simple manner, this speed information being sufficient in particular for small, slow-moving coins, to determine the time of the recording, since the recording area of the image sensor is somewhat larger than the coin area and therefore an uncontrolled leakage from the sensor area is unlikely.
• a lighting device which is activated in a pulse-like manner at the time of the recording, so that good lighting can be achieved on the basis of the determination of the time of the recording, the duration of the lighting being determinable depending on the speed of the coin.
• FIGS. 1 - 4 different states of movement of the coin in relation to an image sensor
• FIGS. 5 and 6 show a schematic illustration of the scanning of coins with ripples.
• the device according to the invention is installed in a coin validator, preferably in the coin channel, in which the other measuring systems of the coin validator are also present, and the device described can be designed as a subsystem of the coin validator control.
• the device has an image sensor, with the image sensor being understood to mean the entire recording device with optics.
• a lighting device is arranged to the
• Image sensor is assigned and which is a flash light function, ie a pulsed illumination of the coin surface is generated.
• a device is shown schematically in FIG. 1 and it has the image sensor 2 arranged in the area of a coin track 1 with corresponding optics as well as an evaluation unit 3 which is part of the coin validator control and a lighting arrangement 4.
• the receiving device designed as the image sensor 2 is adjusted with the optics in such a way that a certain field of view and a certain focus area are specified, a coin 5 to be photographed being arranged in this area so that no optical distortions or darkening occur.
• the image sensor 2 the representation of which indicates the coverage area, is provided with a multiplicity of columns and rows formed from pixels, which are connected to the evaluation unit 3 and which, individually or in areas, are evaluated by the evaluation unit 3 for their initialization and activation for the reading process of the data can be controlled from the sensor and for the actual recording.
• the recording is the process of "electronic fixation" of the optical image, i.e. with an electronic "lock” the optical one
• the point in time of the Recording can be determined via the evaluation unit 3 at the desired measurement position or at the desired location.
• the point in time of the Recording can be determined via the evaluation unit 3 at the desired measurement position or at the desired location.
• the point in time of the Recording can be determined via the evaluation unit 3 at the desired measurement position or at the desired location.
• the first coin 5 in the direction of movement 6 is the first one
• the evaluation unit 3 determines the diameter of the coin 5, which is stored as the first measured value of the system.
• the desired coverage area is determined from the diameter.
• FIG. 3 For this additional control of the passage, reference is made to FIG. 3, in which a pixel line 9 on the center line is activated with respect to the diameter of the coin 5. This activation is carried out by activation of the evaluation unit 3 after the diameter of the coin 5 has been recognized. In this case, the first scan line 7 can be deactivated. Scanning the leading edge of the coin 5 on the center line continuously provides the progress of the passage of the coin through the system. With the temporal information of the scanning of the front edges and the distances traveled in each case, the respective speed and, if desired, the respective acceleration can be determined, which then serve to determine the time of arrival of the coin at the measuring position.
• the rows and columns of the image sensor are initialized by the evaluation unit 3 in the height and width specified by the diameter of the coin 5 as a coverage area at the receiving location and triggered at the pre-calculated time. This is shown in FIG. 4, in which the coin is shown in the desired overlap area 10 with the image sensor.
• the overlap area of the image sensor 2 to be recorded can be optimally selected through the previously determined diameter of the coin and the point in time at the measuring position determined from the speeds or accelerations.
• the overlap or Drawing area limited by the control of the rows and columns by the evaluation unit 3, whereby the time for reading out the image data is reduced to a minimum. If the evaluation of the data is coordinated with this, even the areas of the coverage area 10 located outside the circular image can be suppressed to save space in the working memory, ie these areas are not forwarded by the evaluation unit 3 with regard to their signals.
• the lighting arrangement 4 is triggered by the evaluation unit 3, which likewise determines the exposure time from the previous information about the speed and the diameter. Diffuse, uniform and bright illumination of the coin is required for reproducible, shadow-free illumination of the coin surface during the recording. As already mentioned, this is only activated at the time of recording due to the high power consumption.
• the lighting for the recording can be arranged, for example, by a plurality of rings
• LEDs are designed with a diffuse reflector.
• an exposure control of the picture must be carried out with the help of a targeted control of the lighting. This is necessary because circulation coins have a considerably strong spectrum of contamination and oxidation and thus reflectivity. Furthermore, optics with a fixed diaphragm are usually used for cost reasons. Because of the expected high running speed of the coin, exposure control through the exposure time should be excluded if possible. The exposure must be made as short as possible to avoid sharp movements. There is still the possibility of controlling the feed current of the lighting elements or a gain control of the image sensor.
• a lighting is required for the control of the coin inlet, which can be designed as point or line lighting with lower light intensity or energy than the main lighting in the area.
• the lighting for the entry control must be activated several times, if not continuously over the entire period of the coin entry.
• this lighting for the inlet control is also controlled by the evaluation unit 3, which basically monitors the inlet. It can also determine the average brightness of the coin that is used for exposure control.
• the procedure for eliminating the time of recording can be simplified by dispensing with an additional check according to FIG. 3 of the run. Monitoring is then only achieved via the first column, the time of the passage of the first edge and the time of the apex, which, however, cannot be exactly determined due to the tangential entry, being determined. If necessary, the time at which the rear edge passes through can also be recorded. As above, using the diameter, the speed can be determined and the time of recording can be predicted from the speed, the time of passage of the rear edge also being able to be checked. The simplified scanning is permitted if the boundary conditions are so time-uncritical and the coin movements are continuous enough that an exact run control is not necessary.
• a column within the scanning area 8 can be scanned in the first column. The time of reaching this position can then be used in determining the speed together with the distance between the columns.
• monitoring can only be envisaged over one line.
• the problem with this monitoring is to determine the correct position of the line to be scanned. A compromise must therefore be made regarding accuracy. Otherwise, this procedure also their edge and the rear edge of the coin are detected, with this information the center position of the coin can be determined. With this type of scanning, a larger scanning range of the image sensor is required.
• image sensors that do not permit freely positionable reading out of image data, but which also make it possible to read pixels in blocks or to switch down to a resolution that is several times smaller.
• the aforementioned scanning can be carried out by means of columns and possibly lines, the columns and lines then having a reduced number of pixels.
• FIG. 5 and 6 show a so-called corrugation test which can be carried out with the preferred exemplary embodiment.
• the entry of the coin into the image sensor or the measuring system is monitored by quickly scanning the first column and the apex of the coin, i.e. whose diameter, as mentioned, determined.
• discontinuities can be rated as ripples.
• the detection of polygonal coins is also possible.
• an enlargement of the upper coin edge 11 is shown as it passes through the first column 7 of the image sensor 2.
• the repeated change of the top pixel as it passes through the vertex is recognized as a ripple. Knowing the coin speed can also be used to determine the width of the reef.
• An expanded form with two columns 7, 12 lying next to one another simplifies the detection of a reef ice, since then two pixels lying next to one another each deliver two negated signals. Their change indicates the presence of corrugation on the coin edge 11.
• a ripple depth of the dimensions of a pixel of the image sensor was assumed in FIG. 6. Depending on the resolution of the image sensor, the ripple depth can also be several pixels. Then the ripple depth becomes a measurable characteristic of the coin.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Testing Of Coins (AREA)
• Basic Packing Technique (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

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Cited By (2)

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Citations (6)

Family Cites Families (7)

• 2004
  • 2004-02-19 JP JP2006501897A patent/JP4543029B2/ja not_active Expired - Fee Related
  • 2004-02-19 WO PCT/EP2004/001600 patent/WO2004075124A1/de not_active Ceased
  • 2004-02-19 AT AT04712521T patent/ATE467200T1/de active
  • 2004-02-19 US US10/546,140 patent/US7552811B2/en not_active Expired - Fee Related
  • 2004-02-19 CA CA2516111A patent/CA2516111C/en not_active Expired - Fee Related
  • 2004-02-19 ES ES04712521T patent/ES2342602T3/es not_active Expired - Lifetime
  • 2004-02-19 EP EP04712521A patent/EP1599844B1/de not_active Expired - Lifetime
  • 2004-02-19 DE DE502004011125T patent/DE502004011125D1/de not_active Expired - Lifetime

Patent Citations (7)

Non-Patent Citations (1)

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