JP5216301B2 - Media identification device - Google Patents

Description

  The present invention relates to an apparatus for detecting a medium such as a coin and a medium identifying apparatus for identifying a surface pattern of the coin or the like.

  As an identification device that reads a surface pattern of a coin or the like passing on a conveyance path, for example, a device described in Patent Document 1 is known. The image reading apparatus described in this document includes a position sensor that detects passage of a reading medium conveyed by a conveying apparatus, and a CCD camera that images the reading medium when the reading medium reaches a reading portion. .

  However, in the above document, the medium detection sensor is located in a place where the number of the medium detection sensors increases and does not affect the imaging range of the pattern of the medium because the imaging area becomes large when identifying various media having different external shapes. Cannot be installed. Therefore, at present, a medium position detection sensor is composed of a light emitting element and a light receiving element that are arranged to face each other with a reading portion interposed therebetween.

  Further, as an identification device that reads a surface pattern of a coin or the like, for example, a device described in Patent Document 2 is known. In this document, image data of a circular object is divided into a plurality of annular areas, and the presence or absence of a pattern for each fan-shaped area divided into fan-shaped areas is detected, and the circular object is detected based on the presence / absence data of the pattern. The pattern is identified.

  In addition, in an identification device that reads the surface of a medium, a medium image that is an image of the imaged medium because the imaging magnification changes depending on the apparatus even if the same medium is imaged due to variations in parts such as lenses and variations in the assembly of the apparatus. For example, the outer shape of the medium image, the diameter of the medium image, and the like are different. Therefore, the feature information area of the medium image used for identification is enlarged to absorb the variation in the image size for each apparatus.

  In addition, since the medium is transported in the normal transport path, the space of the transport path is secured more than the thickness of the medium, and when the height position through which the medium passes changes, the imaging distance changes, and the The size changes.

JP 2005-284338 A Japanese Patent Application No. 10-318654

  According to the conventional example, in the apparatus that reads the pattern on the surface of the conveyed medium with an image, the medium detection sensor is mounted in the thickness direction of the medium in order to detect whether the medium has entered the imaging region. ing. The medium detection sensor adjusts the sensor transmission amount to be constant before loading the medium, and performs medium detection based on whether or not the sensor light shielding amount when the medium passes is greater than or equal to a certain value. Thereafter, the image is taken by an imaging means such as a camera, and the outer shape and surface pattern of the medium are identified from the taken image.

  In the medium identification device, the same reference medium image is stored between different medium identification devices, and the type of the medium is determined from the degree of coincidence between the reference medium image and the medium image obtained by imaging the conveyed medium. However, the imaging magnification when a medium image is captured for each apparatus varies depending on the environment, assembly, installation, component variations, and the like. As a result, the size of the picked-up medium image is different, and a pattern at a position different from the assumed position may be determined as a medium matching degree determination target. In order to allow the difference between the feature region of the medium image that is the target of determination of the degree of coincidence of the medium due to such environment, assembly, installation, component variation, etc., and the position of the feature region of the reference medium image stored in advance, Conventionally, it has been necessary to enlarge the characteristic area of the medium image, and the detailed pattern cannot be identified.

  Furthermore, if foreign matter such as lint, piece of paper, or dust stays on the sensor optical axis while the medium is being transported, the sensor for imaging the camera will not be able to detect the medium, and the imaging range will be imaged at an improper timing. There is a problem that the apparatus malfunctions without being imaged in a normal state, such as being imaged in a state where a part of the medium is not included.

  The object of the present invention is to adjust the magnification of the camera using a medium detection sensor to improve the performance of pattern recognition, and to identify when the conveyed medium reaches the imaging area even if foreign matter and dust stay. It is an object of the present invention to provide a medium identification device that can be used.

A storage unit that preliminarily stores a reference medium image that is an image used for medium identification, an imaging unit that captures an image of the medium conveyed by the conveying unit, and a predetermined position of the medium image that is an image of the medium captured by the imaging unit Detecting means; and a first correcting means for matching the size of the medium image and the reference medium image by correcting the reference medium image or the medium image picked up by the image pickup means at a predetermined magnification from a predetermined position ; A medium identifying apparatus comprising: a second correcting unit configured to match a position of a predetermined pattern between a medium image and a reference medium image having the same size by the first correcting unit.

  According to the present invention, a fine pattern can be detected regardless of the medium transport state, and a highly accurate medium identification device can be provided. Further, it is possible to provide a medium identification device that reduces false detection due to foreign matter, dust, and the like.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, for example, an automatic transaction apparatus such as an ATM (Automated Teller Machine) installed in a financial institution such as a bank, and further, a coin identification device built in various devices that handle coins such as a settlement machine and a ticket vending machine. It is about.

  FIG. 1 is an internal structural view of a coin identifying device provided inside an ATM according to the present invention. Reference numeral 101 denotes a casing of the coin identification device, and a deposit / withdrawal port 102 is provided on one end side of the upper surface thereof. A coin to be deposited is inserted into the deposit / withdrawal port 102, and a coin to be dispensed or a coin to be returned is released. The deposit / withdrawal port 102 is an embodiment of the return port in the present invention. Inside the deposit / withdrawal port 102, a rotatable bucket 102a for receiving input coins and discharge coins is provided. Reference numeral 103 denotes a feeding unit, which separates coins discharged downward from the deposit / withdrawal port 102 by the rotation of the bucket 102a one by one by a separation mechanism and sends them to the identification unit 104. The identification unit 104 discriminates the authenticity and denomination of the coins to be deposited. Reference numeral 105 denotes a temporary storage unit that temporarily holds the coins identified by the identification unit 104 as being true coins.

  Reference numeral 106 denotes a denomination stacker that stores the received coins in denominations, and 111 denotes a deposit conveyance unit that conveys the deposited coins. When the deposit transaction is established, the coins held in the temporary holding unit 105 are distributed to the denomination stacker 106 by the deposit transport unit 111 after the denomination is identified through the identification unit 104.

  Reference numeral 113 denotes a withdrawal conveyance unit, which includes a horizontal conveyance unit 112 and a vertical conveyance unit 114. The horizontal conveyance unit 112 includes a belt that conveys coins and a separation mechanism that separates the coins on the belt one by one and sends them to the vertical conveyance unit 114. The vertical conveyance unit 114 is a mechanism that conveys coins between opposed belts. Reference numeral 115 denotes a horizontal conveyance belt, which receives coins discharged from the lower part of the money type stacker 106 at the time of withdrawal on the belt and sends the coins to the withdrawal conveyance unit 113.

  A coin cassette 107 stores coins of various denominations. Reference numeral 116 denotes a vertical conveyance belt that conveys coins fed out from the coin cassette 107 and conveys coins stored in the coin cassette 107. The coin cassette 107 is set in the coin discriminating apparatus 101 at the start of work, and the stored coins are drawn out and distributed to the denomination stacker 106. At this time, the coins fed out are discharged from the vertical conveyance unit 114 through the dispensing conveyance unit 113 to the deposit / withdrawal port 102, fed one by one by the feeding unit 103, and the denomination is identified by the identification unit 104. Thereafter, the money is transferred to the money type stacker 106 by the deposit conveyance unit 111. Reference numeral 110 denotes a collection cartridge that collects forgotten coins remaining in the deposit / withdrawal port 102, rejected coins whose identification result is determined to be abnormal among the withdrawal coins, and the like.

  A collective stacker 108 collects coins that cannot be distributed to the money type stacker 106 when the money type stacker 106 is full. In this collective stacker 108, coins of various denominations are mixed and stored. Further, when the remaining amount of coins in the denomination stacker 106 decreases, the collective stacker 108 pays out stored coins and replenishes the denomination stacker 106. At this time, the coins fed out are discharged from the vertical conveyance unit 114 through the dispensing conveyance unit 113 to the deposit / withdrawal port 102, fed one by one by the feeding unit 103, and the denomination is identified by the identification unit 104. Thereafter, the money is transferred to the money type stacker 106 by the deposit conveyance unit 111. Reference numeral 109 denotes a withdrawal determination unit made up of a magnetic sensor, which is provided in the vicinity of the deposit / withdrawal port 102 (exit of the withdrawal transport unit 113).

  FIG. 2 is a block diagram of the identification unit in part A of FIG. Each component is connected to the bus 200. The control unit 201 gives an instruction to each component and controls the identification unit in the A part of FIG. For example, there is control to a transport unit that transports a medium. The storage unit 205 (also referred to as a first storage unit) includes parameters such as magnification for each apparatus, and feature information extracted from images of coins for domestic six denominations and conductivity extracted from eddy current loss of coins. Templates such as information are recorded. Further, the reference medium image, the center position of the reference medium image, the radius of the reference medium image, the imaging magnification of the reference medium image, the correction magnification, and the like are stored in advance.

  The pattern determination unit 208 compares the feature area of the coin image registered in advance in the storage unit 205 with the feature area extracted from the image of the coin imaged by the pattern detection unit 203. The denomination and authenticity are determined based on the pattern.

  The medium detection unit 202 determines whether or not a coin has been conveyed. The medium detection saving unit 206 is a memory that temporarily holds data input at regular intervals from the medium detection unit 206 in order to determine whether the medium has been conveyed at the time of identification. An image saving unit 207 is a memory that temporarily holds an image captured at the time of identification so that the pattern determination unit 208 can determine the image.

  The magnetism determination unit 209 compares the feature information of the coin eddy current loss registered in the storage unit 205 in advance with the feature information extracted from the eddy current loss of the coin detected by the magnetism detection unit 204. For the conductivity information, the denomination and authenticity are determined.

  The coin determination unit 210 identifies a coin from the results obtained from the pattern determination unit 208 and the magnetic determination unit 209, and identifies the denomination and authenticity of the corresponding coin.

  FIG. 3 is an internal structural diagram of the identification unit in the A part of FIG. 1, and includes a medium detection unit 202, a pattern detection unit 203, and a magnetic detection unit 204.

  The conveyance path 301 is composed of a flat belt on a loop, and is rotated so that the coin 302 is conveyed in one direction A by a drive unit (not shown) that drives the flat belt. The coins 302 are conveyed one by one on the conveyance path 301 in a separated state, and the pattern detection unit 203 is instructed to take an image at the timing when the medium detection unit 202 reaches the detection region 303. To do. The pattern detection unit 203 detects the outer shape of the coin 302 and the pattern on the surface of the coin 302, and the pattern determination unit 208 determines the outer shape and pattern of the coin 302. Further, when the conveyed coin 302 passes through the magnetic detection unit 204, the magnetic detection unit 204 detects the eddy current loss of the coin 302 and determines the conductivity of the coin 302.

  FIG. 4 is a partial structural diagram of the identification unit of FIG. 3, and is a structural diagram of the magnetic detection unit 204 provided in the coin identification device as viewed from the side.

  The magnetic detection unit 204 is provided with a coil 401a on the upper side of the conveyance path and a coil 401b on the lower side, and a magnetic field is generated from these coils. And when the coin 302 passes a magnetic detection part, the coils 401a and 401b are detecting the eddy current which generate | occur | produces in a coin.

  FIG. 5 is a partial structural view of the coin identifying unit in FIG. 2, and is a structural view of the pattern detecting unit 203 provided in the coin identifying apparatus as viewed from the side.

  The pattern detection unit 203 determines the outer shape and pattern of the coin 302. Inside the pattern detection unit 203, light emitting elements 501 are provided in an annular shape obliquely from the side, and uniformly illuminate the entire imaging area. A condensing lens 503 for capturing the reflected light generated on the surface of the coin 502, an image sensor 504 that receives the reflected light through the condensing lens 503, and a transparent material such as glass that transmits the reflected light generated on the surface of the coin 302. And a member 505 for optically detecting the uneven shape (pattern or inscription) on the surface of the coin 502. The transparent member 505 here refers to all transparent materials that transmit light, such as light-transmitting glass or light-transmitting plastic.

  FIG. 6 is a partial structural view of the coin identifying unit in FIG. 2, and is a structural view of the medium detecting unit 202 provided in the coin identifying apparatus as viewed from above.

  Inside the medium detection unit 202, a pair of light projecting and receiving elements is provided on the side surface of the coin, and is configured by a light emitting element 601 and a light receiving element 603 that receives irradiation light emitted from the light emitting element 601 through the slit 602. Whether the coin 302 has reached the medium detection area 303 is optically detected. Reference numeral 604 denotes an imaging range for imaging the conveyed medium.

  FIG. 7 shows a processing flow of medium identification of the medium.

  In medium identification, medium detection is performed by transmission amount acquisition processing 701 to medium length calculation 703, the medium is imaged by medium imaging 704, and a captured image is acquired, and pattern identification is performed by center calculation 705 to pattern determination 712. Details of each step will be described below with reference to (1) to (12).

  (1) In the transmission amount acquisition process 701, the medium detection saving unit 206 sequentially converts the transmission amount input from the light receiving element 603 from the medium detection unit 202 at regular intervals t to the buffer area (second storage means in FIG. 8-4). When the final buffer area is reached, the transmission amount input from the light receiving element 603 is stored in the first buffer area. Further, in the transmission amount acquisition process 701, the transmission amount of the light receiving element 603 is stored in the buffer area at regular intervals t, and the transmission amount B input at the present time and the transmission amount before a predetermined time (for example, transmission amount before 4 × t). ) Compare A and calculate B / A.

  (2) In the medium detection determination 702, the medium detection unit 202 calculates a threshold value 802 from the transmission amount ratio B / A calculated in the transmission amount acquisition process 701, and detects the medium based on whether the light is blocked from the threshold value 802. Judgment is made. Note that there are a method of storing the ratio of the transmission amount and the threshold value 802 in the storage unit 205 or a method of calculating by a certain function.

  Details of the transmission amount acquisition processing 701 and the medium detection determination 702 will be described with reference to FIGS.

  FIG. 8A is a waveform when the medium detection unit 203 detects a coin. The horizontal axis represents time, and the vertical axis represents the light shielding level. In this waveform, when there is no medium, the light receiving element 603 is transmitted by irradiation from the light emitting element 601 of the medium detecting unit, so that the light shielding amount is reduced and the light shielding level is lowered. On the contrary, when the medium is conveyed to the medium detection area, the light shielding amount of the light receiving element 603 increases and the light shielding level becomes high.

  Conventionally, when the coin 302 has been transported and the light shielding amount of the light receiving element 603 of the medium detection unit becomes larger than the fixed threshold value 801, it is determined that the medium has been transported, and an imaging instruction is given to the pattern detection unit 203.

  However, the medium detection unit 202 may carry foreign matter such as lint and dust from the deposit / withdrawal port 102 together with coins. When the foreign matter stays in the medium detection area of the medium detection unit 202 and the light shielding amount of the light receiving element 603 becomes larger than the fixed threshold value 801, the medium detection unit cannot detect coins. For this reason, it is impossible to instruct the pattern detection unit 203 to take an image, and the identification device cannot identify the conveyance medium.

  In this embodiment, the coin is not detected by the light shielding amount of the light receiving element 603 with respect to the fixed threshold value 801, but the coin is detected from the ratio of the amount of light transmitted to the light receiving element 603 as shown in FIG. (Change means)

  FIG. 8D is a buffer area of the medium detection saving unit 206 that temporarily stores the transmission amount input from the light receiving element 603 at regular intervals from the medium detection unit 202.

  Even if foreign matter or dust remains, medium detection and contour detection can be performed with the remaining transmission amount of the light receiving element 603 as shown in FIG.

  (3) Subsequently, in the medium length calculation 703, the medium detection unit 202 determines the difference between the time when the medium is detected in the medium detection determination and the time when the medium cannot be detected, that is, the medium is detected by the medium detection unit 202. The outer shape of the coin is calculated from the time when the light shielding amount is equal to or greater than the threshold value and the medium transport speed by reaching the detected position (first calculation means). Even when the conveyance speed of the coin identification unit is not constant, a mechanism for outputting a pulse for the medium conveyance distance such as an encoder to the coin identification unit 104 is configured, and the determination can be made based on the number of pulses of the encoder for the time required for passing the medium. good.

  (4) The pattern detection unit 203 captures a medium with the medium imaging 704 and acquires a captured image.

  Hereinafter, the center calculation 705 to the pattern determination 712 will be described.

  (5) The pattern detection unit 203 calculates the center of the coin image from the image captured in the center calculation 705. A method for calculating the center position of the medium image by center calculation will be described with reference to FIGS.

  In FIG. 9B, 920 represents the center of the imaging range. Reference numeral 921 denotes a medium image that is an image of the imaged medium. Reference numeral 922 represents the center of the medium image. Reference numeral 604 denotes an imaging range that is an area captured by the camera. It should be noted that the camera as the imaging means is installed so that the predetermined positions in the imaging area coincide. That is, the pattern detection unit 203 is positioned in advance, and in the present embodiment, the center of the imaging range is set to be the center 920 of the captured image.

  For each line in the horizontal axis (X-axis) direction of the captured image, the midpoint position 902 is a midpoint between the first position 901 of a pixel having a certain threshold or more and the last position 903 of a pixel having a certain threshold 904 or more. As for the frequency distribution 905 at the midpoint position 902 of each line, the highest distribution is defined as the X coordinate of the center of the medium image.

  For each line in the vertical axis (Y-axis) direction of the captured image, the midpoint position 912 is a midpoint between the first position 911 of a pixel having a certain threshold value or more and the last position 913 of a pixel having a certain threshold value 914 or more. The highest distribution of the frequency distribution 915 at the midpoint position 912 of each line is set as the Y coordinate of the center of the medium image.

  In this manner, the relative position of the center 922 of the medium image when the center of the captured image is set as the origin is determined.

  (6) The pattern detection unit 203 moves the center position 922 from the center position 922 to the first position or the last position of pixels having a certain threshold value or more with respect to the line where the center 922 of the medium image is calculated by the radius calculation 706. The radius of the circular medium is calculated from the average amount of displacement.

  (7) The pattern detection unit 203 matches the center position of the captured medium image with the center position of the reference medium image in the medium center correction 707). The medium center correction will be described with reference to FIGS.

  FIG. 10 shows a reference medium image. The reference medium image 1001 is a medium image created from images captured by transporting the reference medium to a plurality of devices before shipment. Reference numeral 1002 denotes a feature area which is an area for determining the degree of coincidence by pattern identification. Reference numeral 1004 denotes a method of dividing the reference medium image 1001 into a sector area 1003 for each of a plurality of annular areas from the center 1005 of the reference medium image.

  Note that the reference medium image, the center position of the reference medium image, the radius of the reference medium image, the imaging magnification of the reference medium image, and the like are stored in advance in the storage unit 205.

  FIG. 11 shows a reference medium image and a captured medium image. Here, the medium center correction 707 moves the image so that the center 922 of the captured medium image calculated by the center calculation 705 matches the center 1005 of the reference medium image stored in advance.

  (8) The pattern detection unit 203 determines the type of the conveyed medium from the size of the captured medium image as a pre-processing for pattern identification in the denomination determination 708. In other words, this is a process for determining the type of the medium from the radius of the medium calculated by the radius calculation 706 based on a table or the like indicating the relationship between the size of the medium and the type of medium in which the type of the conveyed medium is stored in advance. . Note that this process only narrows down the types of media to be processed in the subsequent processes, and the type of medium is not finally determined in this process.

  (9) The pattern detection unit 203 uses the displacement amount correction 709 and the medium image 921 captured due to variations in the environment, assembly, parts, installation, and the like, and a reference that is the same image on a different device stored in the storage unit 205 in advance. In order to correct the difference in imaging magnification of the medium image 1001, the medium center correction 707 multiplies the displacement amount from one of the centers to the feature region by the correction magnification in both media images in which the center positions of the media images are matched. The displacement amount of the feature area of the reference medium image and the displacement amount of the feature area of the captured media image are made to coincide with each other from the center of both media images.

  That is, by correcting the reference medium image or the captured medium image from a predetermined position to a predetermined magnification, the sizes of the medium image and the reference medium image are matched (first correction unit).

  Here, the displacement amount correction 703 will be described with reference to FIGS. 12A and 12B are images obtained by capturing the same coin 302 using different apparatuses X and Y. FIG. 1201a and 1201b represent respective medium images. 1202a and 1202b represent feature regions used for the pattern determination 712. 1204a and 1204b represent the centers of the imaging range. 1205a and 1205b represent the centers of the captured medium images. Reference numerals 1206a and 1206b denote imaging ranges.

  FIG. 12C is an image obtained by superimposing the medium image 1201 a captured by the apparatus X and the medium image 1201 b captured by the apparatus Y. Since the imaging magnification of the pattern detection unit of apparatus X apparatus Y varies depending on assembly variations of parts and apparatus, as shown in FIG. 12-3, relative to the center of feature areas 1202a and 1202b used for pattern determination 712 of coin 302 The position will also be different.

  Therefore, conventionally, in order to enable identification of the coin type with a plurality of devices, the feature region of the position used for determination of the degree of coincidence is expanded and identified as a region 1203. If the feature area is large, the fine pattern area to be used for the determination cannot be extracted, and the pattern determination 712 with high accuracy cannot be performed. Also, the coin feature area is often an area where the area with the pattern and the area without the pattern are adjacent to each other. It is difficult to extract a significant feature if the pattern area is large. Did not improve. In addition, for the forged coins and the altered coins, since the significant feature cannot be captured for the above-described reason, the exclusion performance is not improved.

  A displacement amount correction 709 is performed by multiplying a correction magnification by a region at a relative position of the reference medium image with the center 922 of the medium image calculated from the center calculation 705 as the origin. In the displacement amount correction 709, the region of the relative position (X1, Y1) from the center 922 of the medium image is changed to the region of the relative position (a × X1, a × Y1) from the center 922 multiplied by the stored correction magnification. Moving.

  When coins are transported at a constant speed in the transport direction, the medium detection unit 202 applies the transport speed to the time when the coins are taken out from the time when the coins are input in the medium length calculation 703. Since the distance r1 is the diameter of the coin, the imaging magnification 2 × r2 / r1 of the pattern detection unit can be calculated from the length of the medium and the medium radius r2 of the captured image (second calculation means). In this case, the storage unit 205 need not store the correction magnification for each apparatus. Even when coins are not transported at a constant speed, an encoder is prepared in the apparatus, and the number of pulses passing through the medium is counted by the medium detection unit, thereby calculating the outer shape of the medium and calculating the correction magnification. it can. The correction magnification is multiplied by the displacement amount of the feature area, but may be multiplied by the reference medium image.

  (10) In the image conversion 710, the pattern detection unit 203 makes the center 922 of the captured medium image after the medium image captured by the displacement amount correction 709 as shown in FIG. Are divided into sector regions 1301 for each of a plurality of annular regions from the center so as to have the same size and the same number of pixels as the sector regions 1003 stored together with the reference medium image 1001, and the pixels in each region Is calculated from the number of pixels of the sector area 1003 of the corresponding reference medium image 1001, and the image is converted as one pixel which becomes the feature amount of the area. For the reference medium image 1001 as well, the average of the pixels in the area 1003 divided in a sector shape for each of the plurality of annular areas from the center 1005 of the reference medium image is stored as one pixel that is the feature amount of the area. Yes.

(11) In the rotation search 711, the pattern detection unit 203 rotates the fan-shaped area including the characteristic area 1303 of the medium image converted by the image conversion 710 in the direction A in FIG. The angle having the highest degree of coincidence with the feature amount of the sector area including the area 1002 is determined as the angle at which the medium is conveyed, the medium image is rotated to the angle, and the position of the characteristic area of the medium image and the reference medium image Is made to match (second correction means).
Although the degree of coincidence is determined by rotating only the feature area, a feature amount of the basic medium image is obtained by rotating a part of the medium image such as a medium image in an area equidistant from the feature area from the center of the image or the medium image itself. It is possible to make a higher determination by determining the degree of coincidence.

  (12) The pattern determination unit 208 compares the image of the angle determined by the rotation search 711 in the pattern determination 712 with the feature in the feature position area of the coin registered in the storage unit 205 in advance. Judge whether it is a pattern.

  As described above, conventionally, the imaging magnification of the imaging unit varies from device to device due to variations in the environment, devices, parts, installation, assembly, etc., so that it is stored in advance with a media image that is an image of the imaged media, There has been a shift in the position of the feature area, which is the pattern area for determining the degree of coincidence of the pattern, with the reference medium image, which is an image used as a reference for pattern determination. For this reason, in order to compensate for the positional deviation, identification is performed by setting a large pattern region as a feature region used for matching determination.

  Therefore, in the present embodiment, the imaging magnification for each apparatus is stored, and the pattern detection unit 206 captures the medium image obtained by capturing the correction magnification that is the ratio of the reference imaging magnification that is the imaging magnification of the reference medium image and the imaging magnification, or the reference image. By multiplying the media image, correction is made to match the size of the reference media image and the captured media image, the detailed position of the feature area is calculated, and high-precision determination and identification using more detailed patterns are performed. Make it possible. The reference imaging magnification may be stored in advance or may be calculated from the reference medium image. The effect of the present invention can also be obtained by storing the correction magnification instead of the imaging magnification.

  The pattern detection unit 206 converts the medium image picked up by the image pickup unit into an annular shape around a predetermined position of the medium, and rotates and moves the feature region of the medium image based on the center of the medium image. Correction for matching the feature areas of the image and the reference medium image is performed. Then, the pattern determination unit 208 detects the detailed position of the pattern by determining the degree of coincidence with the position of the feature area of the reference medium image. For this reason, the position of the pattern used for the determination can be detected regardless of the angle of the medium to be conveyed, and accurate identification is possible. Instead of rotating the feature area of the medium image, the feature area of the reference medium image may be rotated.

  The predetermined position of the medium image may be any position that can be determined as a unique location from the pixel distribution of the medium image. For example, in the case of a coin or the like, the center of the circle may be set as a predetermined position, and when a hole is opened in a predetermined place such as a paper sheet, the position may be set as the predetermined position.

  In addition, there is a case where the size of the medium image picked up by the image pickup means changes due to the change in the distance at which the picked-up medium is picked up due to lint or the like on the transport path in the transport direction. is there.

  Even in such a case, in the present invention, the medium detection unit 206 calculates the outer shape of the medium using the detection sensor, and calculates the ratio between the outer shape of the captured medium image and the outer shape of the medium measured by the detection sensor. cure. As a result, even if the size of the captured medium image changes, it is possible to provide feedback to the imaging magnification and the correction magnification stored in the storage unit 205. In other words, the imaging magnification and the correction magnification can be dynamically changed according to the captured medium image. Further, it can be shared with a medium detection sensor, and the cost can be reduced.

  As a result, coins can be determined and identified in more detail, and can be eliminated even if the medium is forged or altered.

  Conventionally, when foreign matter or dust stays from the outside, the medium cannot be detected by the medium detection unit, and subsequent identification cannot be performed. In the present invention, the threshold for performing the medium detection determination can be dynamically changed in accordance with the rate of change between the transmission amount of the sensor when the medium passes and the transmission amount of the sensor before a predetermined period. Even when dust stays, by detecting the presence / absence of the medium and the outer shape from the remaining transmission amount, a plurality of media can be distributed by the subsequent medium distribution device.

  In the present embodiment, a detailed pattern portion of a coin can be detected, and a design is made so as not to cause a problem even with foreign matter from the outside, and a coin identifying device with excellent identification performance is provided.

  In this embodiment, a coin is used as a medium, and a coin apparatus has been described. However, a medium that can be transported, such as a paper sheet, a card, or a game coin, may be used. Applicable in general. Further, a biometric image used for biometric authentication such as face authentication and finger vein can be used as an identification target, and can be used to detect that the identification target to be imaged is within the imaging region.

Internal structure diagram of coin recognition device Block diagram of the coin identification unit Internal structure diagram of the coin identification part Magnetic detector internal structure diagram Internal structure diagram of pattern detector Media detector internal structure diagram Media identification process flow Waveform during medium detection with fixed threshold Waveform during medium detection with fluctuation threshold Waveform of medium detection when foreign matter stays Buffer for the media detection save unit Figure of media image center position calculation Captured image Reference media image Diagram of center correction of imaging medium Image captured by the pattern detector of device X Image captured by the pattern detector of device Y Diagram of media images captured by different devices superimposed Figure of fan-shaped section of captured media image

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Housing | casing of a coin identification device, 102 ... Deposit / withdrawal port, 103 ... Feeding part, 104 ... Identification part, 105 ... Temporary holding part, 106 ... Money-type stacker, 107 ... Coin cassette, 108 ... Collective stacker, 109 ... Delivery Gold discriminating unit, 110... Collection cartridge, 111 .. depositing and transporting unit, 112 .. lateral transporting unit, 113... Dispensing transporting unit, 114 ... vertical transporting unit, 115. DESCRIPTION OF SYMBOLS Control part 202 ... Medium detection part 203 ... Pattern detection part 204 ... Magnetic detection part 205 ... Memory | storage part 206 ... Medium detection evacuation part 207 ... Image evacuation part 208 ... Pattern determination part 209 ... Magnetic determination Part, 210 ... coin determination part,
301 ... Conveying path, 302 ... Coin, 303 ... Medium detection area,
401a ... coil, 401b ... coil,
501 ... light emitting element, 503 ... condensing lens, 504 ... imaging element, 505 ... transparent member,
601 ... Light emitting element, 602 ... Slit, 603 ... Light receiving element, 604 ... Imaging range 801 ... Fixed threshold value, 802 ... Variable threshold value 901 ... First position of a pixel having a constant threshold value for each line in the X-axis direction, 902... Middle point position of each line in the X axis direction 903... Last position of a pixel having a certain threshold value in each line in the X axis direction 904... Threshold value 905. The first position of a pixel having a certain threshold value for each line in the Y-axis direction, 912... The middle position of each line in the Y-axis direction 913... Threshold value, 915... Frequency distribution of the midpoint position in the Y-axis direction, 920... Center point of imaging range, 921... Captured media image, 922... Center of captured media, 924. ... standard Body image, the characteristic region of 1002 ... reference medium image, 1003 ... Sector Region, 1004 ... regions sectored per the reference medium image annulus, 1005 ... reference medium center of the image,
1201a ... Coin image on device X, 1201b ... Coin image on device Y, 1202a ... Feature region of coin image, 1202b ... Feature travel of coin image, 1203 ... Feature region of conventional method, 1204a ... Imaging with device X The center of the image, 1204b, the center of the captured image in the device Y, 1205a, the center of the coin image in the device X, 75b, the center of the coin image in the device Y,

Claims (4)

A medium identification device for identifying a medium,
Conveying means for conveying the medium;
First storage means for storing in advance a reference medium image, which is an image used for medium identification;
Imaging means for imaging the medium conveyed by the conveying means;
Means for detecting a predetermined position of a medium image that is an image of the medium imaged by the imaging means ;
First correction means for matching the sizes of the medium image and the reference medium image by correcting the reference medium image or the medium image picked up by the image pickup means at a predetermined magnification from the predetermined position ;
2. A medium identifying apparatus comprising: a second correcting unit configured to match a position of a predetermined pattern between the medium image and the reference medium image having the same size by the first correcting unit. The medium identification device according to claim 1,
A detecting means for detecting that the medium to be conveyed has reached a predetermined position;
The medium identifying apparatus according to claim 1, further comprising a first calculating unit that calculates a size of the medium from information obtained by detecting the conveyed medium by the detecting unit.   3. The medium identifying apparatus according to claim 2, further comprising: a second calculating unit that calculates the predetermined magnification from a ratio between the medium size calculated by the first calculating unit and the medium image size. The detection means detects the medium when the transmission amount of the sensor exceeds a threshold value,
The medium detection device according to claim 2, further comprising a changing unit that changes the threshold value.

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