JP2011103088A - Paper sheet identification unit and paper sheet processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper sheet identification unit capable of appropriately correcting the deterioration of sensitivity in each light receiving element of an image sensor for reading out a reflected image of a paper sheet and capable of improving reliability. <P>SOLUTION: When a reflected image reading means reads out a reflected image of a paper sheet, a sensitivity level detection means detects a sensitivity level from an output during the reading in each light receiving element of a first image sensor. A correction coefficient updating means updates a correction coefficient based on a reference value of a sensitivity level of each light receiving element of the first image sensor which is detected by the sensitivity level detection means after updating a preceding correction coefficient. For instance, the reference value of the sensitivity level may be an average value or the like of the sensitivity levels of the light receiving means detected by the sensitivity level detection means after updating a preceding correction coefficient. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a paper sheet identification unit for identifying the type and authenticity of a paper sheet being conveyed along a conveyance path, and a paper sheet processing apparatus to which this paper sheet identification unit is applied.

  Conventionally, financial institutions such as banks have installed automatic teller machines (hereinafter referred to as ATMs) that handle various transactions such as deposit transactions and withdrawal transactions in stores, etc., in response to user input operations. ing. As is well known, an ATM has a banknote processing apparatus provided with a banknote identification unit for identifying the authenticity and denomination of banknotes involved in deposit transactions and withdrawal transactions.

  A banknote processing apparatus has a banknote conveyance path which connects a money classification cartridge and a deposit / withdrawal port, and conveys a banknote along this banknote conveyance path. A banknote identification unit has an image sensor which reads the image of the banknote currently conveyed along this banknote conveyance path. A banknote identification unit identifies the type and authenticity of a banknote using the image of the banknote read using this image sensor.

  In addition, there is a banknote identification unit that identifies the type and authenticity of banknotes not only using the above-described image but also using a magnetic pattern read from the banknote, a detected thickness, and the like.

  A conventional general banknote recognition unit includes, as an image sensor, a line sensor in which a plurality of light receiving elements are arranged in a line. The image sensor is arranged in a direction in which a plurality of light receiving elements are arranged in a direction orthogonal to the banknote transport direction in the banknote transport path (hereinafter referred to as the main scanning direction). The reflected image of the banknote is read by arranging the light source on the same side as the line sensor with respect to the banknote transport path. Further, the transmission image is read by arranging the light source and the line sensor so as to face each other across the banknote conveyance path.

  The sensitivity of the plurality of light receiving elements of the image sensor varies. For this reason, a correction coefficient by which the output value is multiplied is stored for each light receiving element, and a read image of the image sensor is corrected using the correction coefficient, thereby obtaining a corrected image in which variation in sensitivity between the light receiving elements is suppressed. . The denomination and authenticity are identified by this corrected image.

  Since the sensitivity of the light receiving element changes (deteriorates) due to dirt, aging, etc., it is necessary to update the correction coefficient in accordance with this change. The image sensor that reads the transmission image detects the output of each light receiving element at an appropriate timing such as a waiting time waiting for the user when the banknote is not positioned on the banknote transport path. Then, for each light receiving element, a correction coefficient for adjusting the detected output value to an appropriate value may be calculated and updated to the calculated value.

  On the other hand, an image sensor that reads a reflected image will be affected by dirt on the banknotes when the output of each light receiving element when receiving reflected light from the banknote identified during operation is updated to a correction coefficient that matches the appropriate value. become. In order to suppress this effect, the output of the light receiving element that receives the reflected light from some areas such as the four corners of the banknote that are estimated to be less dirty is updated to a correction coefficient that matches the appropriate value, and this update is performed. Based on the ratio of the correction coefficient before and after the update of the received light receiving element, a proposal has been made to update the correction coefficient of other light receiving elements (see Patent Document 1).

JP 2007-34448 A

  However, the configuration described in Patent Document 1 is based on the premise that the degree of sensitivity deterioration is uniform among the light receiving elements of the line sensor, and does not consider the variation between the light receiving elements. It was. Moreover, in some light receiving elements, the output may decrease due to adhesion of dust or the like.

  Therefore, in the configuration of Patent Document 1, it is not possible to appropriately set the correction coefficient for each light receiving element of the image sensor that reads the reflected image. That is, the accuracy of the correction image (identification image) used for denomination and authenticity identification is lowered. As a result, there was a problem that the identification accuracy of banknotes was lowered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a paper sheet identification unit capable of appropriately correcting the deterioration of sensitivity for each light receiving element of an image sensor that reads a reflected image of a paper sheet and improving reliability. It is in.

  Another object of the present invention is to provide a paper sheet processing apparatus to which the paper sheet identification unit is applied.

  The paper sheet identification unit according to the present invention is configured as follows in order to solve the above-described problems and achieve the object.

  The reflection image reading unit reads a reflection image of the paper sheet conveyed along the conveyance path. The reflected image reading means includes a first light source that illuminates the paper sheet, and a plurality of light receiving elements that receive the reflected light, arranged on one side facing the paper sheet conveyed along the conveyance path. Are arranged in the main scanning direction orthogonal to the sheet transport direction. The correction coefficient storage means stores a correction coefficient for the output of each light receiving element of the first image sensor. This correction coefficient is a coefficient for correcting the sensitivity variation between the light receiving elements of the first image sensor. The identification image generation unit generates an identification image obtained by correcting the reflection image of the paper sheet read by the reflection image reading unit using a correction coefficient. That is, the identification image is an image in which variation in sensitivity between the light receiving elements of the first image sensor is suppressed. Then, the identification unit identifies the type, authenticity, and the like of the paper sheet based on the generated identification image.

  The sensitivity level detection means detects the sensitivity level from the output during this period for each light receiving element of the first image sensor when the reflection image reading means reads the reflection image of the paper sheet. Further, the correction coefficient updating means calculates a correction coefficient for each light receiving element of the first image sensor based on a sensitivity level reference value detected by the sensitivity level detecting means for the light receiving element after the previous correction coefficient update. Update. The reference value of the sensitivity level may be, for example, the average value of the sensitivity levels detected by the sensitivity level detection unit for the light receiving element after the previous correction coefficient update.

  For example, for each light receiving element of the first image sensor, the correction coefficient update means includes a sensitivity level reference value obtained at the time of the previous correction coefficient update, and a sensitivity level reference value detected after the previous correction coefficient update. Then, the correction coefficient may be updated based on the above. Thereby, the correction coefficient can be updated according to the deterioration from the sensitivity level at the time of the previous update.

  Therefore, since a correction coefficient can be set for each light receiving element of the first image sensor in accordance with the deterioration of sensitivity of the light receiving element, an appropriate identification image can be generated. Thereby, the fall of the identification precision of paper sheets can be suppressed and reliability can be improved.

  Further, for example, when the reflected image reading unit reads the reflected image of the paper sheet, the sensitivity level detecting unit detects the average value of the output during this period as the sensitivity level for each light receiving element of the first image sensor. What is necessary is just composition. Thereby, it is possible to suppress the influence of characters and designs drawn on the paper sheet, detect the sensitivity level for each light receiving element, and update the correction coefficient.

  The sensitivity level detection unit may be configured not to detect the sensitivity level when the type of the paper sheet identified by the identification unit is not a predetermined target type. Thereby, the correction coefficient of each light receiving element is updated based on the sensitivity level detected only for the paper sheet of the target type. Therefore, it is possible to detect the sensitivity level for each light receiving element and update the correction coefficient without being affected by the difference in the types of paper sheets.

  A second light source that illuminates the paper sheet, and a second image sensor in which a plurality of light receiving elements are arranged in the main scanning direction, and is conveyed along the conveyance path. A transparent image reading means for reading the transmitted image of the paper sheet to be read is provided, and a stain detecting means for detecting the degree of dirt on the paper sheet is provided by the transparent image read by the transparent image reading means. The sensitivity level detection means may be configured not to detect the sensitivity level when the degree of dirt detected by the dirt detection means exceeds a predetermined level. As a result, the correction coefficient of each light receiving element can be updated without using paper sheets with a high degree of contamination.

  In addition, the dirt detecting means is configured to detect the degree of dirt for each area obtained by dividing the paper sheet, and the sensitivity level detecting means is configured to detect the dirt detected by the dirt detecting means in any area. It may be configured that the sensitivity level is not detected when the degree exceeds a predetermined level.

  In this way, the correction coefficient of each light receiving element can be updated more appropriately.

  According to the present invention, the correction coefficient can be set for each light receiving element of the first image sensor in accordance with the deterioration of the sensitivity of the light receiving element, so that an appropriate identification image can be generated. Therefore, it is possible to suppress the deterioration of the paper sheet identification accuracy and improve the reliability.

It is the schematic which shows the external appearance of an automatic teller machine. It is a block diagram which shows the structure of the principal part of an automatic teller machine. It is the schematic which shows the internal structure of a banknote process part. It is a block diagram which shows the structure of the principal part of a banknote identification part. It is the schematic of a reflected image reading part and a transmissive image reading part. It is a figure which shows the line sensor of a reflected image reading part and a transmissive image reading part. It is a figure explaining the reading procedure of the reflective image of a banknote by a line sensor, and a transmitted image. It is a flowchart which shows a banknote identification process. It is a flowchart which shows an update related information storage process. It is a flowchart which shows a correction coefficient update process. It is a figure explaining the example which divides a bill into a plurality of fields.

  Embodiments of the present invention will be described below.

  FIG. 1 is a schematic diagram showing an external appearance of an automatic teller machine, and FIG. 2 is a block diagram showing a configuration of a main part of the automatic teller machine. The automatic teller machine 1 (hereinafter referred to as ATM 1) is applied with a paper sheet processing apparatus (a banknote processing unit 4 described later) according to an embodiment of the present invention. The paper sheet identification unit (banknote identification part 20 mentioned later) concerning embodiment of this invention is applied to. ATM1 is installed in a store of a financial institution or a convenience store. ATM1 processes various transactions, such as a deposit transaction and a withdrawal transaction, according to a user's input operation. The ATM 1 includes a main control unit 2, a display / operation unit 3, a banknote processing unit 4, a coin processing unit 5, a card / detail processing unit 6, a passbook processing unit 7, a biological information reading unit 8, And a communication unit 9. The main control unit 2 controls the operation of each part of the ATM 1 main body and processes the transaction requested by the user.

  The display / operation unit 3 includes a display 3a provided on the front surface of the main body, a touch panel 3b attached on the screen of the display 3a, and the like. The display / operation unit 3 displays an operation guidance screen for the user on the display 3a. In addition, the display / operation unit 3 detects a user's input operation related to a personal identification number and transaction content (transaction type, deposit / withdrawal amount, etc.) by detecting the pressed position of the touch panel 3b.

  The banknote processing unit 4 processes deposit / withdrawal banknotes. A bill deposit / withdrawal port 4a for storing deposit / withdrawal bills is provided on the front of the main body. The bill deposit / withdrawal port 4a is provided with a shutter. In addition, the banknote deposit / withdrawal port 4a is provided with a partition plate for distinguishing between storage locations for deposited banknotes, withdrawn banknotes, and returned banknotes. The banknote processing unit 4 restricts the insertion and removal of banknotes to and from the banknote deposit / withdrawal port 4a by opening and closing the shutter. The detailed configuration of the banknote processing unit 4 will be described later.

  The coin processing unit 5 conveys coins along a coin conveyance path formed between a coin deposit / withdrawal port 5a provided on the front surface of the main body and a coin cartridge housed inside the main body. Moreover, the coin process part 5 has a coin identification part which identifies a money type and authenticity for every coin currently conveyed along a coin conveyance path.

  The card / detail processing unit 6 takes in a cash card (hereinafter simply referred to as a card) inserted into a card insertion slot 6a provided on the front of the main body, and stores card information (financial information) recorded in the magnetic stripe of the card. Read institution number, store number, account number, etc.) and rewrite card information. If the inserted card is an IC card, the data recorded on the IC chip of the card is read or rewritten as necessary. The IC chip stores biometric information (registered information) of the user who is the owner of the card. Further, the card / detail processing unit 6 has a printing unit (not shown) for printing the transaction contents on the specification. The card / specification processing unit 6 discharges the specification printed with the transaction contents to the specification discharge port 6b provided on the front of the main body.

  The bankbook processing unit 7 has a printing unit (not shown) that takes in a bankbook inserted into a bankbook insertion slot 7a provided on the front of the main body and prints a transaction history for the bankbook. In addition, the passbook processing unit 7 is recorded on a page turning mechanism for turning over the page of the imported passbook, a bar code reader for reading a bar code indicating a page number printed on the passbook, and a magnetic stripe attached to the passbook. It also has a magnetic head or the like that reads the bankbook information (financial institution number, store number, account number, etc.).

  The biometric information reading unit 8 includes a biometric information reading sensor 8a provided on the front surface of the main body. This biological information reading sensor 8a reads the finger vein pattern of the user. Here, as the biometric information reading sensor 8a, a sensor that reads a finger vein pattern is taken as an example, but other types of biometric information such as palm veins, irises, and retinas may be read. The biometric information reading unit 8 collates the biometric information (read information) of the user read by the biometric information reading sensor 8a with the biometric information (registered information) recorded on the IC chip of the card, and the degree of similarity. To authenticate whether the user and the cardholder are the same person. Further, the communication unit 9 controls communication with a host device (not shown) of the financial institution via the network.

  Next, the structure of the banknote process part 4 is demonstrated. FIG. 3 is a schematic diagram showing the internal configuration of the banknote processing unit. The banknote processing unit 4 houses the denomination cartridges 11 to 14 and the collection cartridge 15 inside. The money type cartridges 11 to 14 and the collection cartridge 15 are detachable from the main body. The money type cartridges 11 and 12 store 10,000 yen bills. The money type cartridge 13 stores a thousand yen bill. The money type cartridge 14 stores a 2000 yen bill and a 5000 yen bill. The collection cartridge 15 stores banknotes determined to be unusable for transactions. Banknotes stored in the money type cartridge 14 (2,000 yen banknotes and 5,000 yen banknotes) and banknotes stored in the recovery cartridge 15 are not used as withdrawal banknotes. For this reason, the money type cartridge 14 and the recovery cartridge 15 may not have a bill feeding mechanism.

  Moreover, the banknote process part 4 has the temporary storage part 16 which accommodates and hold | stores a deposited banknote etc. temporarily. Furthermore, it has the banknote conveyance path 17 which connects the deposit / withdrawal port 4a, the money type cartridges 11-14, the collection | recovery cartridge 15, and the temporary storage part 16. FIG. The banknote processing unit 4 includes a banknote transport unit (not shown) that transports banknotes along the banknote transport path 17. Moreover, a banknote conveyance part controls the flapper provided in the branching point of the banknote conveyance path 17, etc., and controls the conveyance destination of the banknote currently conveyed. Furthermore, the banknote processing part 4 has the banknote identification part 20 which identifies the money type of the banknote currently conveyed along the banknote conveyance path 17, and authenticity. The banknote recognition part 20 reads the reflected image and transmitted image of the banknote for each banknote conveyed along the banknote conveyance path 17.

  FIG. 4 is a block diagram showing the configuration of the main part of the bill recognition unit. The banknote recognition unit 20 includes a control unit 21, an image processing unit 22, a reflection image reading unit 23, a transmission image reading unit 24, a storage unit 25, and an input / output unit 26. The control unit 21 controls the operation of each unit of the banknote recognition unit 20. The reflected image reading unit 23 reads the reflected image of the banknote being transported through the banknote transport path 17. The transmissive image reading unit 24 reads a transmissive image of a banknote being conveyed through the banknote conveyance path 17.

  As shown in FIG. 5, the reflected image reading unit 23 includes a light source 23 a and a line sensor 23 b arranged on one side of the banknote transport path 17. In addition, the transmission image reading unit 24 is arranged with the light source 24a and the line sensor 24b facing each other with the banknote conveyance path 17 interposed therebetween. As shown in FIG. 6, the line sensors 23b and 24b have a plurality of light receiving elements arranged in a line (here, 100 light receiving elements). The line sensors 23b and 24b are arranged so that the light receiving elements are aligned in the main scanning direction (direction perpendicular to the paper surface in FIG. 5) orthogonal to the banknote transport direction in the banknote transport path 17. Two-digit numbers (“00” to “99”) shown in FIG. 6 indicate the numbers of the light receiving elements. Each light receiving element of the line sensor 23b receives light emitted from the light source 23a and reflected on the surface of the bill being conveyed. Each light receiving element of the line sensor 24b receives light emitted from the light source 24a and transmitted through the banknote being conveyed.

  As shown in FIG. 7, the reflection image reading unit 23 and the transmission image reading unit 24 are arranged in the main scanning direction with the light receiving elements of the line sensors 23 b and 24 b with respect to the banknote transported through the banknote transport path 17. Read an image for one line. The reflected image reading unit 23 and the transmissive image reading unit 24 each time the banknote transport unit transports a certain amount of banknotes in the sub-scanning direction (the direction perpendicular to the main scanning direction and the banknote transport direction in the banknote transport path 17). The image for one line in the main scanning direction is read repeatedly. The reflected image reading unit 23 connects the reflected images read line by line in the main scanning direction from the time when the banknote passes through the reading position of the line sensor 23b until the time when the trailing edge passes. One reflection image (read reflection image) is obtained. Similarly, the transmission image reading unit 24 connects the transmission images read line by line in the main scanning direction between the reading position of the line sensor 24b and the passage of the banknote until the trailing edge passes. Thus, a transmission image (read transmission image) for one bill is obtained.

  The image processing unit 22 corrects the read reflected image read by the reflected image reading unit 23 in accordance with the sensitivity variation of each light receiving element of the line sensor 23b and generates a reflected image for identification. Further, the image processing unit 22 corrects the read transmission image read by the transmission image reading unit 24 in accordance with the sensitivity variation of each light receiving element of the line sensor 24b, and generates an identification transmission image. The above-described correction is a process of correcting the output A (n) of each light receiving element to a value (correction value) obtained by multiplying the light receiving element by a correction coefficient stored in the storage unit 25.

  The storage unit 25 stores a correction coefficient for each light receiving element of the line sensors 23b and 24b. Here, the correction coefficient of each light receiving element of the line sensor 23b is expressed as α (n) (n is the number of the light receiving element, here “00” to “99” shown in FIG. 6), and the line sensor 24b The correction coefficient of each light receiving element is β (i) (i is the number of the light receiving element, and here “00” to “99” shown in FIG. 6).

  As described above, when the number of light receiving elements of the line sensor 23b is 100, the storage unit 25 stores 100 correction coefficients (α (00) to α (99)) for the line sensor 23b. Similarly, when the number of light receiving elements of the line sensor 24b is 100, the storage unit 25 stores 100 correction coefficients (β (00) to β (99)) for the line sensor 24b. The correction coefficient α (n) applied to the line sensor 23b corrects variations in sensitivity between the light receiving elements of the line sensor 23b. Specifically, this is a coefficient for converting the magnitude (detection value) of the output A (n) at that time into the same value when the amount of light received by each light receiving element is the same. Similarly, the correction coefficient applied to the line sensor 24b corrects variations in sensitivity between the light receiving elements of the line sensor 24b.

  The bill identifying unit 20 has a function of updating the correction coefficients α (n) and β (i) at an appropriate timing. The timing for updating the correction coefficients α (n) and β (i) can be set individually.

  As is apparent from the above description, the image processing unit 22 uses the output coefficient A (n) stored for each light receiving element in the output A (n) of each light receiving element in the reflected image read by the line sensor 23b. A reflection image for identification corrected to the multiplied value is generated. In addition, the image processing unit 22 performs identification by correcting the output B (i) of each light receiving element in the transmission image read by the line sensor 24b to a value multiplied by the correction coefficient β (i) stored for the light receiving element. A transparent image is generated.

  The image processing unit 22 identifies the denomination and authenticity of the banknote using the generated identification reflection image and identification transmission image. This identification result is notified to the banknote processing unit 4 via the input / output unit 26. The banknote processing unit 4 determines the banknote transport destination according to the notified identification result, and instructs the banknote transport unit. A banknote conveyance part conveys a banknote according to this instruction | indication.

  The storage unit 25 stores not only the correction coefficients α (n) and β (i) described above, but also the count value of the number N of processed bills of the target type. Further, the previous reference value x (n) of each light receiving element of the line sensor 23b, the reference value y (i) of each light receiving element of the line sensor 24b, and the like are stored. The previous reference value x (n) is the detected value of the light receiving element or the detected value from the previous correction coefficient α (n) update to the previous correction coefficient α (n) update. It is an average value of correction values multiplied by the correction coefficient α (n). Here, the correction value will be described as an average value. For each light receiving element of the line sensor 23b, the cumulative value p (n) used for calculating the reference value x ′ (n) of the light receiving element from the previous update of the correction coefficient α (n) to the present time is used. Remember.

In addition, about the line sensor 24b, when the banknote is not located between the light source 24a and the line sensor 24b, the output B (i) of each light receiving element is detected. For each light receiving element, the correction coefficient β (i) is calculated as follows: correction coefficient β (i) = output B (i) / reference value y (i)
And the correction coefficient β (i) stored in the storage unit 25 is updated.

  Next, the overall operation of the ATM 1 according to this embodiment will be briefly described. Here, a processing procedure of deposit transaction and withdrawal transaction in ATM 1 will be briefly described.

  In the deposit transaction, the ATM 1 feeds the deposited banknotes inserted into the deposit / withdrawal port 4a one by one to the banknote transport path 17, and the banknote identifying unit 20 identifies the denomination and authenticity. The banknote processing unit 4 transports and stores the denomination and the deposited banknote identified as a genuine note to the temporary storage unit 16. On the other hand, the banknote processing unit 4 returns the banknote that at least one of denomination or genuine note could not be identified to the deposit / withdrawal port 4a and returns it to the user. When the deposit amount is confirmed by the user, the ATM 1 performs a deposit process for depositing the confirmed deposit amount into the user's account (designated account). This depositing process is a process of notifying the host device of the user's account number and deposit amount. The card / detail processing unit 6 issues a statement slip with transaction details printed thereon, or the passbook processing unit 7 prints transaction details on the passbook accepted this time.

  Thereafter, the banknote processing unit 4 feeds out banknotes held in the temporary storage unit 16 one by one, and the banknote recognition unit 20 identifies the denomination and authenticity again. The banknote processing unit 4 transports and stores each banknote in a denomination cartridge identified for the banknote. The banknote processing unit 4 conveys and stores the banknotes, at least one of which is a denomination or a genuine note, to the collection cartridge 15 for storage.

  In the withdrawal transaction, the ATM 1 determines the number of banknotes to be dispensed for each denomination according to the designated withdrawal amount. The banknote processing unit 4 pays out the determined number of banknotes from the denomination cartridges 11 to 13 for each denomination, and the banknote identification unit 20 identifies the denomination and authenticity. The banknote processing unit 4 conveys and stores the banknote that can be identified as a denomination and a genuine note to the deposit / withdrawal port 4a. On the other hand, banknotes for which at least one of denomination or genuine note could not be identified are transported to the collection cartridge 15 and stored. Moreover, whenever a banknote is accommodated in the collection | recovery cartridge 15, one banknote is newly fed out from the money type cartridges 11-13 which let out the banknote.

  When the banknote corresponding to the withdrawal amount is stored in the deposit / withdrawal port 4a, the ATM 1 performs a withdrawal process for withdrawing the withdrawal amount from the user's account (designated account). This withdrawal process is a process of notifying the host device of the account number and withdrawal amount of the user. ATM1 opens the shutter provided in the deposit / withdrawal port 4a, and discharge | releases the banknote accommodated in this deposit / withdrawal port 4a with respect to a user. The card / detail processing unit 6 issues a statement slip with transaction details printed thereon, or the passbook processing unit 7 prints transaction details on the passbook accepted this time.

  Here, the banknote identification process in the banknote identification part 20 is demonstrated. FIG. 8 is a flowchart showing this bill recognition processing. The banknote identification part 20 performs the process shown in this FIG. 8 for every banknote currently conveyed along the banknote conveyance path 17. FIG. When the reflected image reading unit 23 reads the reflected image for one line in the main scanning direction from the bill conveyed along the bill conveying path 17 by the line sensor 23b (s1), the reflected image for the one line. A reflection image for identification is generated (s3). In s3, for each light receiving element of the line sensor 23b, an image obtained by multiplying the output A (n) by the corresponding correction coefficient α (n) is generated. Further, when the transmission image reading unit 24 reads a transmission image for one line in the main scanning direction from the banknotes transported along the banknote transport path 17 by the line sensor 24b (s2), this one line's worth. A transparent image for identification with respect to the transparent image is generated (s4). In s4, an image obtained by multiplying the output B (i) by the corresponding correction coefficient β (i) is generated for each light receiving element of the line sensor 23b.

  When the generation of the reflection image for identification and the transmission image for identification is completed for one banknote (s5, s6), the banknote identification unit 20 identifies the denomination and authenticity of the banknote ( s7). In s7, the reflection image and transmission image template stored for each denomination is compared with the currently generated reflection image for identification and transmission image for identification, and the denomination of the banknote, Identify true and false. Since the details of this identification are known, a detailed description is omitted here.

  When at least one of denomination or authenticity cannot be identified in s7, the banknote recognition unit 20 determines that the banknote is unusable (s10), and notifies the banknote transport unit accordingly. On the other hand, when both the denomination and the genuine note can be identified in s7, the banknote recognition unit 20 determines that the banknote is usable (s8), and notifies the banknote transport unit accordingly. Moreover, the banknote identification part 20 performs the update relevant information storage process used for update of correction coefficient (alpha) (n) of each light receiving element of the line sensor 23b (s9).

  FIG. 9 is a flowchart showing the update related information storage processing according to s9. The banknote identification part 20 determines whether the money type of the banknote is a 10,000 yen banknote (s11). Here, by limiting the denomination of the banknote used for updating the correction coefficient α (n) (in this invention, the target type) to 10,000 yen banknotes, the difference in characters and patterns drawn on the banknotes is The influence on the update related information used for updating the correction coefficient α (n) is suppressed. If it determines with the banknote identification part 20 not being a 10,000 yen banknote by s11, this process will be complete | finished.

  If the banknote identification part 20 determines that the denomination of the banknote is a 10,000 yen banknote, it determines whether the direction of the banknote conveyed along the banknote conveyance path 17 is a predetermined direction ( s12). The direction of the banknote conveyed along the banknote conveyance path 17 has four types concerning front-back inversion and left-right inversion. Here, the influence which the change of the reading image accompanying the difference in direction of a banknote has on the update related information is suppressed. If it determines with the banknote identification part 20 not being the direction predetermined in s11, this process will be complete | finished.

  If the banknote identification part 20 determines with the direction of the banknote currently conveyed along the banknote conveyance path 17 being a predetermined direction, it will determine whether the degree of dirt of this banknote exceeds the predetermined level. (S13). In s13, it determines based on the brightness of the whole transmission image for identification produced | generated about this banknote. For example, the average of the pixel values is calculated for all the pixels of the identification transparent image, and if this is smaller than a predetermined value (first threshold value), the degree of contamination exceeds a predetermined level. judge. If the banknote identification part 20 determines with the grade of the stain | contamination of the banknote currently conveyed along the banknote conveyance path 17 having exceeded the predetermined level, this process will be complete | finished. Thereby, the influence which the dirt of a bill has on the update related information is suppressed.

  The order of the processes related to s11 to s13 described above may be any order.

  In addition, when the average of the pixel values calculated for all the pixels of the transparent image for identification is larger than a separately determined value (second threshold (second threshold> first threshold)), the banknote is worn out. In this way, it is possible to suppress the influence on the update-related information by a worn-out bill or a bill with a hole.

  When the banknote recognition unit 20 determines that the degree of dirt on the banknotes conveyed along the banknote transport path 17 does not exceed a predetermined level (is an appropriate level), the banknote identification unit 20 counts the number of executions N. The count value N is incremented (N = N + 1) (s14). The number of executions N counts the number of banknotes that have been processed after s15.

  The banknote recognition unit 20 adds up the correction value in the sub-scanning direction (the value obtained by multiplying the output A (n) by the correction coefficient α (n)) in the reflection image for identification created this time for each light receiving element of the line sensor 23b. Is divided by the number of lines in the sub-scanning direction as a sensitivity level (s15). That is, the sensitivity level of each light receiving element calculated in s15 is an average value of the correction values of the light receiving elements in the identification reflection image created this time.

  Here, the sensitivity level is the average value of the correction values, but as described above, it may be the average value of the output A (n).

The banknote recognition unit 20 updates the stored cumulative value p (n) for each light receiving element of the line sensor 23b to a value obtained by adding the sensitivity level (n) calculated in s14 for the light receiving element (s16). . That is, in s16, for each light receiving element of the line sensor 23b, the accumulated value p (n) stored in the storage unit 25 is
p (n) = p (n) + sensitivity level (n)
Update to

  Thus, the banknote identification part 20 is a specific denomination (10,000 yen banknote), the direction conveyed by the banknote conveyance path 17 is a specific direction, and the degree of dirt exceeds a predetermined level. The sensitivity level is calculated for each light receiving element of the line sensor 23b for the banknotes that are not. For each light receiving element of the line sensor 23b, the sum of sensitivity levels (n) calculated for the light receiving element is stored as a cumulative value p (n).

  The banknote recognition unit 20 determines whether or not the number N of executions exceeds a predetermined number (for example, 1000 times) (s17). If it determines with the banknote identification part 20 not having exceeded the frequency | count predetermined in s17, this process will be complete | finished. On the other hand, if it is determined in s17 that the predetermined number of times has been exceeded, correction coefficient update processing is executed (s18).

  FIG. 10 is a flowchart showing the correction coefficient update process according to s18. This correction coefficient update process is a process of updating the correction coefficient α (n) of each light receiving element of the line sensor 23b. First, the current reference value x '(n) is calculated for each light receiving element of the line sensor 23b (s21). The current reference value x ′ (n) is a value obtained by dividing the accumulated value p (n) stored at this time by the number of executions N. That is, the average of the sensitivity level from the previous update of the correction coefficient α (n) to the present time (when the current correction coefficient α (n) is updated).

The banknote recognition unit 20 uses the current reference value x ′ (n) calculated in s21 and the previous reference value x (n) stored in the storage unit 25 for each light receiving element of the line sensor 23b, and the storage unit 25. The correction coefficient stored in is updated (s22). In s22, the correction coefficient α (n) of each light receiving element is
α (n) = α (n) × previous reference value x (n) / current reference value x ′ (n)
Update to the value calculated by.

  Moreover, the banknote identification part 20 resets the execution frequency N memorize | stored in the memory | storage part 25, and the accumulation value p (n) (s23). Further, the previous reference value x (n) is updated to x ′ (n) calculated in s21 (s24).

  Thus, this banknote identification part 20 can update correction coefficient (alpha) (n) for every light receiving element of the line sensor 23b which reads a reflected image according to the degree of degradation of the light receiving element. Therefore, since an appropriate reflection image for identification can be generated, a decrease in the identification accuracy of paper sheets can be suppressed, and reliability can be improved.

  At the time of factory shipment, the initial value of the previous reference value is stored in the storage unit 25.

  Moreover, as shown in FIG. 11, a banknote is divided | segmented into a some block (here, the example divided | segmented into 8 blocks of blocks w1-w8 is shown), the degree of dirt is detected for every block, In such a block, a banknote that is soiled larger than the set value may be determined to be a banknote that is not subject to correction coefficient update processing. In this way, it is possible to prevent the correction coefficient α (n) of some of the light receiving elements (light receiving elements that read blocks having a high degree of contamination) from being set to an inappropriate value.

  Moreover, this invention is applicable not only to the banknote identification unit which identifies a banknote, but also to the apparatus which identifies a check, a security, etc.

DESCRIPTION OF SYMBOLS 4 ... Banknote processing part 4a ... Banknote depositing / withdrawing port 17 ... Banknote conveyance path 20 ... Banknote identification part 21 ... Control part 22 ... Image processing part 23 ... Reflection image reading part 23a ... Light source 23b ... Line sensor 24 ... Transmission image reading part 24a ... light source 24b ... line sensor 25 ... storage unit 26 ... input / output unit

Claims (8)

A first light source that illuminates the paper sheet and a plurality of light receiving elements that receive the reflected light are disposed on one side facing the paper sheet that is transported along the transport path. A first image sensor arranged in the main scanning direction orthogonal to the direction, and a reflected image reading means for reading a reflected image of the paper sheet,
Correction coefficient storage means for storing a correction coefficient for the output of each light receiving element of the first image sensor;
An identification image generation means for generating an identification image obtained by correcting the reflection image of the paper sheet read by the reflection image reading means using a correction coefficient stored in the correction coefficient storage means;
In the paper sheet identification unit comprising: an identification unit that identifies the paper sheet by the identification image generated by the identification image generation unit;
Sensitivity level detection means for detecting a sensitivity level from an output during this time for each light receiving element of the first image sensor when the reflected image reading means reads a reflected image of a paper sheet,
Correction coefficient updating means for updating the correction coefficient of each light receiving element of the first image sensor stored in the correction coefficient storage means,
The correction coefficient updating unit corrects the correction coefficient for each light receiving element of the first image sensor based on a reference value of the sensitivity level detected by the sensitivity level detecting unit for the light receiving element after the previous correction coefficient update. Update the paper sheet identification unit.   The correction coefficient updating means includes, for each light receiving element of the first image sensor, a sensitivity level reference value obtained at the time of the previous correction coefficient update, and a sensitivity level reference value detected after the previous correction coefficient update. The paper sheet identification unit according to claim 1, wherein the correction coefficient is updated based on:   The sensitivity level detection means detects, as a sensitivity level, an average value of output for each light receiving element of the first image sensor when the reflection image reading means reads a reflection image of a paper sheet. The paper sheet identification unit according to claim 1 or 2.   The paper sheet identification according to any one of claims 1 to 3, wherein the sensitivity level detection unit does not detect the sensitivity level when the type of the paper sheet identified by the identification unit is not a predetermined target type. unit. A second light source that illuminates the paper sheet, and a second image sensor in which a plurality of light receiving elements are arranged in the main scanning direction, and is transported along the transport path. A transmission image reading means for reading a transmission image of the paper sheet to be printed;
A stain detecting means for detecting the degree of stain on the paper sheet based on the transparent image read by the transparent image reading means,
The paper sheet according to any one of claims 1 to 4, wherein the sensitivity level detection means does not detect the sensitivity level when the degree of dirt detected by the dirt detection means exceeds a predetermined level. Identification unit. The dirt detection means detects the degree of dirt for each area obtained by dividing a paper sheet into a plurality of parts,
The paper sheet according to claim 5, wherein the sensitivity level detection unit does not detect the sensitivity level in any region when the degree of contamination detected by the contamination detection unit exceeds a predetermined level. Class identification unit.   The correction coefficient updating means is configured such that the number of sheets calculated by the sensitivity level detection means for each light receiving element of the first image sensor after the previous correction coefficient update is a predetermined number. The paper sheet identification unit according to claim 1, wherein the correction coefficient of each light receiving element of the first image sensor is updated after reaching. Conveying means for conveying paper sheets along a conveying path;
A first light source for illuminating the paper sheet, and a plurality of light receiving elements for receiving the reflected light, arranged on one side facing the paper sheet conveyed along the conveyance path, A first image sensor arranged in the main scanning direction orthogonal to the conveying direction, and a reflected image reading means for reading a reflected image of the paper sheet;
Correction coefficient storage means for storing a correction coefficient for the output of each light receiving element of the first image sensor;
An identification image generation means for generating an identification image obtained by correcting the reflection image of the paper sheet read by the reflection image reading means using a correction coefficient stored in the correction coefficient storage means;
Identification means for identifying the paper sheet by the identification image generated by the identification image generation means;
In a paper sheet processing apparatus comprising: a transport destination determination unit that determines a transport destination of a paper sheet by the transport unit according to an identification result by the identification unit;
Sensitivity level detection means for detecting a sensitivity level from an output during this time for each light receiving element of the first image sensor when the reflected image reading means reads a reflected image of a paper sheet,
Correction coefficient updating means for updating the correction coefficient of each light receiving element of the first image sensor stored in the correction coefficient storage means,
The correction coefficient updating unit corrects the correction coefficient for each light receiving element of the first image sensor based on a reference value of the sensitivity level detected by the sensitivity level detecting unit for the light receiving element after the previous correction coefficient update. Update the paper sheet processing device.

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