JPWO2016088279A1 - Paper thickness determination method and thickness determination apparatus - Google Patents

Abstract

A thickness determination method for determining the presence or absence of a tape body affixed to a paper sheet by a thickness determination device having a thickness detection sensor and an optical line sensor in order to detect the tape affixed to the paper sheet with high accuracy. An optical image acquisition step of taking an image of a paper sheet conveyed on the conveyance path by an optical line sensor and acquiring an optical image of the paper sheet, a thickness measurement step of measuring the thickness of the paper sheet by a thickness detection sensor, and a paper Tape body candidate detection process for detecting an optical edge on a leaf optical image and detecting a tape body affixed on a paper sheet based on the optical edge, and the tape body is detected by the tape body candidate detection process. The presence or absence of a tape body affixed to a paper sheet by changing the determination criteria between the case where it was detected and the case where it was not detected, and evaluating the measurement value measured in the thickness measurement step based on the determination criterion Constituted by a determining step.

Description

  The present invention relates to a thickness determination method and a thickness determination apparatus for determining the thickness of a paper sheet, and in particular, a paper sheet for determining the thickness of a paper sheet using an optical image in addition to a measured value of the thickness of the paper sheet. The present invention relates to a thickness determination method and thickness determination apparatus.

  2. Description of the Related Art Conventionally, in a banknote processing apparatus that identifies and counts banknotes, banknote thickness determination is performed by an identification apparatus that identifies and counts the denomination, authenticity, correctness, and the like of banknotes. For example, Patent Document 1 discloses a thickness detection device that measures the thickness of banknotes. In this apparatus, when a bill passes between a reference roller that rotates on a fixed rotation shaft and a detection roller that rotates on a rotation shaft that can move up and down, the displacement of the detection roller pushed upward by the bill. The thickness of the banknote is measured based on the amount.

  For example, when a tape is affixed to a banknote, the tape is detected because there is a region where the thickness is larger than that of a normal banknote in a part of the banknote when the thickness of the banknote to be processed is measured. can do. Thereby, in the damage determination for distinguishing between a correct ticket to be reused in the market and a non-reusable ticket, the banknote on which the tape is attached is determined as a damaged ticket, and the banknote is determined as a predetermined storage unit in the apparatus. It can be stored in and collected.

  As a method for determining the presence or absence of a tape attached to a banknote, there is a method for optically detecting a tape on a banknote optical image in addition to a method for measuring the thickness of a banknote. For example, Patent Document 2 discloses an apparatus that determines the presence or absence of a tape body by irradiating a bill with ultraviolet light. In this device, the amount of reflected light obtained by irradiating the banknotes with ultraviolet light by utilizing a tape body such as a transparent tape or a mending tape that exhibits an absorption rate different from that of the banknote surface in the wavelength range of ultraviolet light. Based on this, the presence or absence of the tape body on the banknote is determined.

Japanese Patent No. 4819162 Japanese Patent No. 4058246

  However, in the above prior art, the thickness of the paper sheet may not be accurately determined. For example, regarding the technique described in Patent Document 1, whether or not the measured thickness of a paper sheet is thicker than that of a normal paper sheet is compared with a measured thickness value and a threshold value prepared in advance. Judgment by. However, some paper sheets have a convex portion formed by intaglio printing or the like, and this convex portion may be erroneously detected as a tape. If the thickness of the convex portion is constant, it can be recognized as a convex portion from the measured thickness value, but if the convex portion wears and changes in thickness during distribution in the market, the convex portion is determined from the measured thickness value. It is difficult to specify. In recent years, a tape having a thickness smaller than that of the conventional tape has appeared, and a change in thickness caused by attaching the tape to a paper sheet is small, so that detection by a measured value of the thickness may be difficult.

  In addition, regarding the technique described in Patent Document 2, in order to detect a tape using the optical property of exhibiting a specific absorptance in the wavelength region of ultraviolet light, a measuring system for measuring the optical property by ultraviolet light is necessary. become. Since it is not possible to specify where the tape is to be applied on the banknote, it is necessary to acquire optical characteristics using ultraviolet light for the entire surface of the banknote. Cannot be used. For this reason, in the banknote processing apparatus already utilized on the market, this technique may not be utilized.

  The present invention has been made to solve the above-described problems caused by the prior art. In addition to the measurement value of the thickness of paper sheets, the present invention utilizes optical images that can be obtained by many conventionally used apparatuses. An object of the present invention is to provide a paper sheet thickness determination method and thickness determination apparatus capable of determining with high accuracy the presence or absence of a tape attached to a paper sheet.

  In order to solve the above-described problems and achieve the object, the present invention provides a thickness determination method for determining the presence or absence of a tape body attached to a paper sheet by a thickness determination device having a thickness detection sensor and an optical line sensor. An optical image acquisition step of acquiring an optical image of the paper sheet by capturing an image of the paper sheet transported on the transport path by the optical line sensor, and a thickness of measuring the thickness of the paper sheet by the thickness detection sensor. A tape body candidate detecting step of detecting an optical edge on the optical image of the paper sheet and detecting a tape body affixed on the paper sheet based on the optical edge; and the tape body By changing the determination criteria between the case where the tape body is detected in the candidate detection step and the case where the tape body is not detected, and evaluating the measurement value measured in the thickness measurement step based on the determination criterion, Characterized in that it includes a first determination step of determining whether the tape body affixed to the paper sheet.

  Further, the present invention, in the above invention, the tape body candidate detection step further includes a step of detecting a thickness detection edge based on a change amount in a predetermined direction of a measured value of the thickness of the paper sheet, It is determined that the tape body has been detected when the optical edge obtained from the optical image of the paper sheet and the thickness detection edge obtained from the amount of change in the measured value indicate the characteristics of the tape body. To do.

  Further, in the present invention, in the above invention, the determination criterion includes a threshold value for detecting a tape body, and the threshold value used when the tape body is detected is a tape for detecting a thin tape body. It is characterized by being set to a value different from the threshold value used when no body is detected.

  The present invention is also characterized in that, in the above invention, the paper sheet optical image used for optical edge detection in the tape body candidate detection step is an infrared light image.

  Further, in the present invention, in the above invention, when a tape body is detected on the paper sheet optical image in the tape body candidate detection step, the area where the tape body is detected in the first determination step. Only the measured value of is evaluated.

  Further, in the above invention, the present invention provides the fouling determination step of determining the degree of fouling of the paper sheet based on the optical image of the paper sheet, and the fouling determination to determine the degree of wear of the paper sheet. Select a different template for the case where it is determined that the paper is less worn in the process and the case where the paper is determined to be worn, and the template indicating the thickness of each part of the paper is selected. And a second determination step of determining the presence or absence of the tape body attached to the paper sheet by evaluating the measurement value measured in the thickness measurement step.

  Further, in the present invention, in the above invention, a template selected when it is determined that the paper sheet is less worn and a template selected when it is determined that the paper sheet is worn, The numerical value indicating the thickness of the predetermined region where the thickness changes due to wear is different.

  Further, the present invention is the above invention, wherein the front end of the paper sheet transported through the transport path passes between two rollers forming the thickness detection sensor, and the rear end of the paper sheet is A calculation step of calculating a length in the transport direction of the paper sheet based on a timing of passing between the rollers, and the paper sheet based on the length of the paper sheet calculated in the calculation step And a third determination step of determining whether or not the tape body is affixed to.

  Further, in the present invention according to the above invention, the thickness detection sensor is formed by a plurality of roller pairs arranged in a direction perpendicular to the transport direction of the paper sheets, and forms the roller pair. The thickness of the paper sheet passing between the reference roller on the rotation shaft and the detection roller on the rotation shaft that can be displaced in the thickness direction of the paper sheet is determined based on the displacement amount of the detection roller. Measured at a resolution of 1 μm between 0 and 1023 μm in the vertical direction at a pitch of 0.25 mm in the vertical direction.

  In addition, the present invention is a thickness determination device that measures the thickness of a paper sheet conveyed through a conveyance path and determines the presence or absence of a tape body attached to the paper sheet. A thickness detection sensor for measuring the thickness of the paper sheet, an optical line sensor for capturing a paper optical image of the paper sheet transported on the transport path, and an optical detected on the paper optical image A process for detecting the tape body affixed on the paper sheet based on the edge is performed, and different criteria are selected depending on whether the tape body is detected or not, and the criteria And a control unit that determines the presence or absence of a tape body affixed to the paper sheet by evaluating the measured thickness value.

  According to the present invention, for example, the processing for detecting a tape on a banknote using a banknote optical image is performed, and the thickness of the banknote is determined only when there is a possibility that the tape is attached to the banknote. Therefore, the presence / absence of a tape can be determined with high accuracy even when a thin tape is affixed. Further, it is possible to avoid a situation in which false detections increase by always using a strict threshold.

  In addition, according to the present invention, for a template prepared in advance for evaluating the thickness of each part of the banknote, for example, a banknote whose thickness changes due to wear during circulation in the market, a banknote without wear called a fully sealed ticket A plurality of templates are prepared, such as for a worn banknote, and the presence or absence of a tape is determined with high accuracy by selecting a template according to the degree of wear of the banknote and evaluating the measured thickness value. be able to. For example, even if there is a convex part whose thickness changes greatly due to wear in some areas on the banknote, it is misdetected as a tape because it uses a template for a banknote with a convex part of a new ticket with little wear. It will not be done. Moreover, the presence or absence of the tape affixed on the new ticket can also be determined with high accuracy using a template for bills without wear.

  Moreover, according to this invention, since thickness is measured by the displacement of the roller at the time of the banknote conveyed between two rollers arrange | positioned facing each other, from the timing at which the front end of a banknote conveyance direction passes between rollers. The length of the bill in the conveyance direction can be calculated using the measurement result of the bill thickness obtained until the trailing edge passes between the rollers. When calculating the length of banknotes from the thickness measurement results, the tapes are attached to the banknotes and the thickness increases. Can be determined. For example, by measuring the thickness of a bill at a pitch of 0.25 mm in the transport direction and calculating the bill length from the number of pitch and thickness measurements, the presence / absence of a tape is determined with high accuracy based on the bill length. can do.

  In addition, according to the present invention, when the thickness is measured by the displacement of a roller when a bill to be conveyed passes between two rollers arranged opposite to each other, the thickness of the bill is measured with a resolution of 1 μm with high accuracy. can do. Moreover, since it is possible to measure a thickness of up to 1023 μm with respect to a banknote having a thickness of about 100 μm, the roller supported so as to be displaceable in the thickness direction of the banknote jumped up by the entry of the banknote conveyed at high speed. Even in this case, it is possible to avoid a situation where the measured value at the front end of the banknote exceeds the measurement range by the roller and the measured value cannot be obtained. Even when the roller jumps up due to the entry of the front edge of the banknote, there is a difference in the measurement value between the case of only the banknote and the case where the tape is attached to the banknote. By obtaining, the presence or absence of the tape can be determined.

FIG. 1 is a diagram for explaining a schematic configuration of the banknote recognition apparatus according to the present embodiment. FIG. 2 is a diagram for explaining a schematic configuration of the upper unit and the lower unit constituting the banknote recognition apparatus. FIG. 3 is a block diagram for explaining an outline of a functional configuration of the banknote recognition apparatus. FIG. 4 is a flowchart showing the flow of the bill thickness determination method. FIG. 5 is a diagram illustrating a thickness determination process using a template. FIG. 6 is a flowchart showing a flow of thickness determination processing by edge detection. FIG. 7 is a diagram illustrating a thickness determination process based on the bill length in the transport direction. FIG. 8 is a diagram showing the banknote length in the transport direction calculated from the thickness of the banknote.

  Below, with reference to an accompanying drawing, the thickness determination method and thickness determination apparatus of paper sheets concerning the present invention are explained. The technique according to the present invention can be applied to various paper sheets such as checks, bills, forms, and the like. Hereinafter, a bill will be described as an example.

  FIG.1 and FIG.2 is a figure for demonstrating the structure outline of the banknote identification device 10 which concerns on this embodiment. Conventionally, when processing a banknote with a banknote processing apparatus, the banknote identification apparatus 10 used for identifying and counting the denomination, authenticity, correctness, etc. of each banknote is the thickness of the banknote according to this embodiment. It functions as a thickness determination device that realizes the determination method.

  FIG. 1 is a schematic view of the banknote recognition device 10 as viewed from the side. The banknote recognition apparatus 10 includes two sets of timing sensors 11 and 12 for detecting the transport position of the banknote 100 on the transport path 17, an optical line sensor 13 that acquires an optical image of the banknote 100, and the fluorescence of the banknote 100. It has the fluorescence sensor 14 which acquires a characteristic, the thickness detection sensor 15 which measures the thickness of the banknote 100, and the magnetic sensor 16 which acquires the magnetic characteristic of the banknote 100. The banknote 100 is transported in the direction indicated by the arrow on the transport path 17 and passes between the upper unit 10a and the lower unit 10b of the banknote recognition apparatus 10.

  FIG. 2 is a plan view of each of the upper unit 10a and the lower unit 10b constituting the banknote recognition apparatus 10 as viewed from the conveyance path 17 side. The timing sensors 11, 12, the optical line sensor 13, the thickness detection sensor 15, and the magnetic sensor 16 are configured by a component on the upper unit 10 a side and a component on the lower unit 10 b side. In FIG. 2, the upper-side components are indicated by a and the lower-side components are indicated by b.

  The timing sensors 11 and 12 have a function of detecting the banknote 100 on the transport path 17 by utilizing the fact that light projected and received with the transport path 17 interposed therebetween is blocked by the banknote 100. The timing sensor 11 detects the arrival of the banknote 100 to the banknote identification device 10, and in accordance with the passage of the banknote 100, the banknote 100 is imaged by the optical line sensor 13, the fluorescence characteristic is measured by the fluorescence sensor 14, and the thickness detection sensor. Measurement of thickness by 15 and measurement of magnetic characteristics by the magnetic sensor 16 are performed. Moreover, the detection result of the banknote 100 by the timing sensor 12 is reversed, for example, on the downstream side of the transport path 17 by the banknote processing apparatus in which the banknote recognition apparatus 10 is incorporated, or stored in a predetermined storage unit. It is used for

  The optical line sensor 13 has a function of acquiring a visible light image and an infrared light image of the banknote 100. By the upper unit 13a and the lower unit 13b, a reflected image on the upper surface of the banknote 100, a reflected image on the lower surface, and a transmitted image can be acquired. The fluorescence sensor 14 has a function of acquiring the fluorescence characteristics of the banknote 100 by irradiating the banknote 100 with ultraviolet light and measuring the reflected light. Further, the magnetic sensor 16 has a function of acquiring the magnetic characteristics of the banknote 100 in a state where the banknote 100 is pressed against the upper sensor unit 16a by the bristle roller 16b rotating on the lower side.

  As shown in FIG. 2, the conveyance path 17 is provided with conveyance guides 17c and 17d for regulating the position of the banknotes on both sides in the direction perpendicular to the conveyance direction, and the banknote 100 is located between the conveyance guides 17c and 17d. Is conveyed in the direction indicated by the arrow. Thereby, the optical line sensor 13 acquires an optical image of the entire surface of the banknote 100, the thickness detection sensor 15 measures the thickness of the entire surface of the banknote 100, and the magnetic sensor 16 can acquire magnetic characteristics from the entire surface of the banknote 100. Yes.

  The thickness detection sensor 15 is supported so that the upper detection roller 15a is movable in the bill thickness direction (vertical direction) with respect to the fixed lower reference roller 15b, and is conveyed between the two rollers. The thickness of the bill 100 is measured by measuring the amount of displacement when the position of the upper detection roller 15a moves upward in accordance with the thickness of the bill 100 to be processed.

  The thickness detection sensor 15 measures the thickness of the bill 100 conveyed at a constant speed on the conveyance path 17 at a constant time interval. The timing at which measurement is performed by the thickness detection sensor 15 is controlled using, for example, a rotary encoder or a timer circuit that is linked to a drive motor for the conveyance path 17 that conveys the banknote 100 at a constant speed. By measuring at fixed time intervals, the thickness detection count (measurement count) and the measurement pitch (each measurement) from when the thickness detection sensor 15 detects the front end of the banknote 100 in the transport direction to when the rear end is detected. The distance in the conveyance direction of the banknote 100 can be calculated from the distance interval). For example, when the measurement pitch is 0.25 mm and the banknote 100 has a thickness of 301 counts, the length of the banknote 100 can be calculated to be 75 mm (= 0.25 mm × 300). . However, the method of calculating the length of the banknote 100 in the transport direction is, for example, the time from when the thickness detection sensor 15 detects the front end of the banknote 100 in the transport direction until the rear end is detected, the transport speed of the banknote 100, The method of calculating by

  The thickness detection sensor 15 is composed of a plurality of detection rollers 15a and a reference roller 15b disposed to face the detection rollers 15a. The plurality of detection rollers 15 a are arranged in a direction perpendicular to the conveyance direction of the banknote 100. A predetermined number of detection rollers 15a are used as one channel, and the thickness of the banknote 100 is measured by a plurality of channels of detection rollers 15a. For example, the thickness of the banknote 100 is measured using 12 pairs of detection rollers 15a as one channel and 24 detection rollers 15a for 12 channels. The detection roller 15a is supported so that it can be displaced in the vertical direction independently for each channel, and the bill 100 is divided into regions corresponding to the respective channels, and the thickness is measured in each region. Specifically, as shown in FIG. 2, when the banknote 100 is transported in the direction indicated by the arrow, the banknote 100 is divided into a plurality of strip-shaped areas that are long in the transport direction, and the thickness of each area corresponds to each corresponding area. It is measured by the detection roller 15a of the channel (Ch1, Ch2, Ch3... In the figure). The bill thickness measurement performed using the multi-channel detection roller 15a is disclosed in Japanese Patent No. 4819162 by the applicant of the present application, and thus the details thereof are omitted.

  The thickness detection sensor 15 measures the thickness of the banknote 100 in each channel at a pitch of 0.25 mm in the transport direction. Moreover, the thickness of the banknote 100 is measured with a resolution of 1 μm between 0 and 1023 μm.

  For example, the thickness of a Japanese banknote is 100 μm, but as shown in FIG. 1, the banknote 100 is conveyed at a high speed toward a thickness detection sensor 15 in which a detection roller 15a and a reference roller 15b are vertically opposed to each other. If it enters in between, the impact may cause the detection roller 15a supported so as to be displaceable in the vertical direction to jump upward. The thickness detection sensor 15 can measure the thickness of the bill 100, that is, the displacement of the detection roller 15a up to 1023 μm, so that the measurement value is saturated even when the detection roller 15a jumps beyond the actual thickness of the bill 100. The displacement amount of the detection roller 15a that has jumped up can be measured without doing so.

  Specifically, for example, when the front end of the banknote 100 with a tape (tape body) affixed to a partial region at the front end in the transport direction enters between the rollers, the detection roller 15a of each channel jumps up. There is a difference in the height of the detection roller 15a that has jumped up between the channel that measures the thickness in the region where the film is attached and the channel that measures the thickness in other regions. At this time, for example, if the displacement of the detection roller 15a can only be measured by 512 μm, when the detection roller 15a jumps to a height exceeding this, the measured value shows 512 μm in all the channels where the banknote is detected, and the tape is attached. The specified position cannot be specified. The thickness detection sensor 15 is capable of measuring a displacement of 1023 μm, so that such a situation can be avoided, and the tape attached on the banknote 100 can be detected by comparing the measured values of each channel. It has become.

  FIG. 3 is a block diagram for explaining an outline of a functional configuration of the banknote recognition apparatus 10. The banknote recognition apparatus 10 is connected to the sensor groups of the timing sensors 11 and 12, the optical line sensor 13, the fluorescence sensor 14, the thickness detection sensor 15 and the magnetic sensor 16 illustrated in FIG. 1, and the sensors 11 to 16 of the sensor group. Control unit 20 and storage unit 30 connected to control unit 20.

  The control unit 20 includes a sensor information acquisition unit 21, a denomination identification unit 22, a true / false identification unit 23, a serial number identification unit 24, and a fitness identification unit 25. The sensor information acquisition part 21 has a function which acquires each data which concerns on the banknote 100 from each sensor 11-16 which forms a sensor group.

  The denomination identifying unit 22, the authenticity identifying unit 23, and the serial number identifying unit 24 perform identification processing using the data acquired by the sensor information acquiring unit 21. The denomination identifying unit 22 identifies the denomination of the banknote 100, and the authenticity identifying unit 23 identifies the authenticity of the banknote 100. The serial number identification part 24 identifies and acquires the serial number printed on the banknote 100 by the character recognition process.

  The fitness identification unit 25 includes a thickness determination unit 25A and a comprehensive determination unit 25B. The fitness identification unit 25 has a function of determining the fitness of the banknote 100 using the data acquired by the sensor information acquisition unit 21. The damage identification unit 25 detects the dirt, breakage, tear, etc. of the banknote 100, and can detect the tape attached to the banknote 100 from the thickness of the banknote 100, thereby reusing the banknote 100 in the market. It has a function of determining whether to process as a genuine ticket or a non-marketable ticket. The thickness determination unit 25A performs a plurality of types of determination processing for determining the thickness of the banknote 100, and the comprehensive determination unit 25B finally determines the presence or absence of the tape on the banknote 100 based on the results of these determination processes. However, details of this will be described later.

  The storage unit 30 is a storage device composed of a semiconductor memory, a hard disk, or the like, and stores therein determination data 31 necessary for identifying the denomination, authenticity, correctness, etc. The determination data 31 includes a template 31A and a threshold value 31B. As the template 31A, for example, a reference optical image for comparison with a banknote optical image obtained by imaging the banknote 100 in order to identify a denomination, authenticity, correctness, etc., a waveform indicating fluorescence characteristics and magnetic characteristics acquired from the banknote 100 And a reference waveform and a reference optical image for comparison with images are stored. Moreover, the value for determining the various feature-values acquired from the banknote 100 in order to identify a money type, authenticity, damage, etc. is preserve | saved as the threshold value 31B. The template 31 </ b> A and the threshold 31 </ b> B are prepared in advance for the denomination of the banknote 100 processed by the banknote recognition apparatus 10. The storage unit 30 also stores setting data in which various data measurement methods for identifying the banknote 100 are set, dictionary data for recognizing the serial number by the serial number identification unit 24, and the like. Yes. Moreover, the memory | storage part 30 is utilized also for the preservation | save of the optical image measured by each sensor 13-16, a measured value, the preservation | save of the identification result of the banknote 100, etc. FIG.

  For the process of identifying the denomination of the banknote 100, the process of identifying authenticity, the process of acquiring the serial number, and the process of determining whether the banknote 100 is dirty, broken, torn, etc., the conventional technique can be used. Therefore, detailed description will be omitted, and in the following, the thickness determination method of the banknote 100 realized as a function of the damage identification unit 25 will be described in detail.

  FIG. 4 is a flowchart showing the flow of the bill thickness determination method performed by the fitness identification unit 25. First, an optical image of the entire bill 100 is acquired by the optical line sensor 13 (step S1). In the banknote identification device 10, visible light or infrared light can be applied to the banknote 100 to obtain a reflected image and a transmitted image.

  Next, the thickness of the entire bill 100 is measured by the thickness detection sensor 15 (step S2). Specifically, as shown in FIG. 2, each banknote 100 is divided into a plurality of strip-like areas that are long in the transport direction in correspondence with the plurality of channels of detection rollers 15 a forming the thickness detection sensor 15. The thickness is measured with a resolution of 1 μm between ˜1023 μm. The measurement of the thickness of each channel is repeatedly performed from the front end to the rear end of the banknote 100 with the pitch in the transport direction being set to 0.25 mm. For example, when the length of the banknote 100 in the transport direction is 75 mm, a thickness measurement value of 301 counts can be obtained for each channel with one measurement as one count. The obtained measurement value is stored in the storage unit 30.

  In addition to acquiring an optical image of the banknote 100 by the optical line sensor 13, measuring the thickness of the banknote 100 by the thickness detection sensor 15, acquiring fluorescence characteristics by the fluorescence sensor 14, and acquiring magnetic characteristics by the magnetic sensor 16. And the denomination identification of the banknote 100 is performed by the denomination identification part 22 based on each data obtained by the sensor information acquisition part 21, and the template 31A and the threshold value 31B previously stored in the storage part 30 (step). S3). The denomination identification result is stored in the storage unit 30.

  In a state where the measured thickness values obtained in each region of the banknote 100 and the data indicating the denomination of the banknote 100 are stored in the storage unit 30, the thickness determination unit 25A detects the tape attached to the banknote 100. In order to do so, three determination processes for determining the thickness of the banknote 100 are executed in parallel. Specifically, a thickness determination process (step S10) performed using a signal obtained by the thickness detection sensor 15 and a template 31A indicating the thickness of each part of the bill 100, and infrared light obtained by the optical line sensor 13. Thickness determination processing (step S20) performed by detecting the edge of the tape affixed on the banknote 100 in the image, and the length in the conveyance direction of the banknote 100 calculated based on the signal obtained by the thickness detection sensor 15 (the bill) The thickness determination process (step S30) performed based on (long) is executed in parallel. Details of these processes will be described later.

  When the results of the three determination processes (steps S10, S20, and S30) are obtained by the thickness determination unit 25A, the comprehensive determination unit 25B combines the processing results to determine whether there is a tape attached on the banknote 100. Comprehensive determination processing is performed (step S40). Specifically, if there is a process in which at least one of the three determination processes has a determination result indicating that a tape is attached to the banknote 100, the comprehensive determination unit 25 </ b> B is taped on the banknote 100. It is determined that there is. On the other hand, in all three determination processes, when a determination result indicating that the tape is not attached is obtained, the comprehensive determination unit 25B determines that there is no tape on the banknote 100.

  Next, the details of the three determination processes (steps S10, S20, and S30) performed by the thickness determination unit 25A will be described with reference to FIGS.

  FIG. 5 is a diagram illustrating a thickness determination process performed using a template indicating a reference value for the thickness of each part of the banknote 100. Each process shown in FIG. 5 is executed by the thickness determination unit 25A. Further, template data (determination criteria) used in each process is stored in advance in the storage unit 30 as a template 31A. The thickness template data is data indicating the thickness of each denomination banknote, and is data that can specify the position and thickness of this area even when there are areas with different thicknesses on the banknote.

  For example, as shown in FIG. 5 (a), when the banknote 101 has a convex portion 111 that is thicker than other areas, and the banknote 101 is measured by the thickness detection sensor 15, the same figure (b) is obtained. As shown, measurement data 201 indicating that the convex portion 211 is thicker than other regions is obtained.

  In addition, although typically shown in FIG.5 (b), the measurement data 201, the template data 301, and the data 401 for determination are optical images from which the brightness differs according to the thickness of a banknote. For example, the thickness of the bill is represented by 10-bit data (0 to 1023) between 0 and 1023 μm, and each region on the bill is represented by the lightness corresponding to the bit value (thickness), whereby the thickness is represented as an optical image. Can be processed as

  The thickness determination unit 25A reads the template data 301 corresponding to the banknote 101 shown in FIG. 5A with reference to the template 31A of the storage unit 30 based on the denomination identification result obtained previously. As shown in FIG. 5B, the template data 301 is data indicating that the thickness of the convex portion 311 is thicker than the thickness of other regions.

  Since the template data 301 is a reference value indicating the thickness of each part of the banknote 101, if a tape or the like is not attached to the banknote 101 whose thickness is actually measured, a process of subtracting the template data 301 from the measurement data 201 is performed. As shown in FIG. 5B, the determination data 401 obtained as the difference data is data indicating a uniform thickness without a convex portion.

  Specifically, for example, when the thickness of the convex portion 111 of the banknote 101 distributed in the market is 105 μm and the thickness of the other region is 100 μm, the thickness of the convex portion 311 is 105 μm and the thickness of the other region is 100 μm. The template data 301 is stored in advance in the storage unit 30 as a template 31A. For this reason, the determination data 401 obtained by subtracting the template data 301 from the measurement data 201 of the bill 101 without a tape shows 0 (zero) uniformly on the entire surface. On the other hand, for example, when a tape having a thickness of 30 μm is attached to the bill 101, only the portion corresponding to the tape on the determination data 401 indicates the thickness of 30 μm. 401 can be used to detect the tape. Actually, in consideration of variations in the thickness of the bill 101 and measurement errors, for example, the determination data 401 is determined with a threshold value of 15 μm, and a tape having a thickness of 30 μm is detected. A threshold value used as a determination criterion is also stored in advance in the storage unit 30 as the threshold value 31B.

  Among banknotes, there are those in which the thickness of the convex portions on the banknotes changes due to wear during circulation in the market. Specifically, an unused bill called a completely closed ticket (hereinafter referred to as “new ticket”) has a thick convex portion, and the convex portion is worn while being distributed in the market, and the banknote ( In the following description, it is referred to as “normal ticket”), and the thickness of the convex portion is smaller than that of the new ticket.

  For example, when the measured value of the convex part of the normal ticket is 105 μm, whereas the measured value of the convex part of the new ticket is 130 μm as shown in FIG. The value of the convex portion of the judgment data obtained by subtracting the thickness of 105 μm of the convex portion of the normal ticket template data prepared in the above is 25 μm. As a result, since the threshold value of 15 μm is exceeded, it is determined that the tape is stuck. That is, although the tape is not attached, the convex portion of the new ticket is erroneously determined as a tape.

  In the banknote identification device 10, in order to avoid such erroneous determination, a plurality of types of template data are prepared in advance for banknotes that are worn. And the process which determines the abrasion degree of a banknote is performed, generation | occurrence | production of a misjudgment is avoided by selecting the template data according to the abrasion degree and determining thickness. Hereinafter, a specific method will be described by taking as an example the case of using two types of template data.

  FIG. 5D is a flowchart showing a method for determining the thickness using two types of template data. First, using the optical image which imaged the banknote 101 under visible light, the stain | pollution | contamination determination of the banknote 101 is performed (step S11). In the stain determination, for example, the banknote optical image is binarized, and if there is a pixel indicating black in the background area indicating white on the banknote 101, it is determined that there is dirt. In addition, although the presence or absence of a wrinkle, a crease, etc. is determined, detailed description is abbreviate | omitted since the stain | pollution | contamination determination of a banknote is a technique conventionally performed as a part of damage determination.

  As a result of the stain determination, if the banknote 101 is detected to be dirty, broken, wrinkled, etc., and determined not to be a new ticket but a normal ticket (step S12; No), the template data 301 for the normal ticket is used. Then, a process for determining the presence or absence of the tape is performed (step S13). On the other hand, if it is determined that the bill 101 is not a stain, a fold, a wrinkle or the like as a result of the stain determination and is determined to be a new ticket (step S12; Yes), the template data 301 for the new ticket is used. Processing for determining the presence or absence of a tape is performed (step S14).

  Specifically, as shown in FIG. 5C, when the measured value of the convex portion is 130 μm on a new ticket with no tape attached, it is not the normal ticket template data but the new ticket template. The thickness is determined using the data. The thickness of the convex portion of the new ticket template data is set to 120 μm, which is thicker than that of the normal ticket template data. Thereby, the difference obtained by subtracting the value of the template data from the measured value of the convex portion is 10 μm, which is equal to or less than the threshold value of 15 μm. As a result, a correct determination result that the tape is not attached to the new ticket can be obtained.

  When a tape having a thickness of 30 μm is attached to the convex portion of the new ticket, the measured value is 160 μm, and the difference from the new ticket template data is 30 μm. As a result, since the value is larger than the threshold value of 15 μm, it is possible to obtain a correct determination result that the tape is attached to the new ticket.

  In addition, about the area | regions other than a convex part, it is set to 100 micrometers same as the template for normal tickets also in the template for new tickets. As a result, even when a 30 μm thick tape is applied to an area other than the convex portion of the new ticket and the thickness is 130 μm, the difference from the new ticket template is 30 μm, which is larger than the threshold value of 15 μm. The tape can be detected based on the indication.

  Thus, in the banknote identification device 10, for banknotes having a region whose thickness changes due to wear, a plurality of types of template data are prepared in advance according to the degree of wear, and the degree of wear of the banknote is specified. After performing the determination process, the template data corresponding to the degree of wear is selected and the thickness determination is performed, so that the presence or absence of the tape attached to the banknote can be determined with high accuracy.

  Next, the thickness determination process performed by detecting the optical edge and the thickness detection edge of the tape affixed on the banknote 100 will be described. FIG. 6 is a flowchart showing a flow of thickness determination processing by edge detection. Each process shown in FIG. 6 is executed by the thickness determination unit 25A. In addition, a threshold value (determination criterion) used in each process is stored in advance in the storage unit 30 as a threshold value 31B. The edge detected using the optical image acquired by the optical line sensor 13 is distinguished as an optical edge, and the edge detected using the thickness measurement value acquired by the thickness detection sensor 15 is distinguished as a thickness detection edge. In either case, the edge of the tape is detected.

  First, processing for detecting an optical edge is performed using an optical image captured by irradiating the bill 100 with infrared light (step S21). The processing for detecting the optical edge included in the optical image can be performed using the conventional technique, and thus the details are omitted. For example, for the infrared light image, an optical edge detection device such as a differential filter or a Sobel filter is used. An optical edge is detected by performing optical image processing to which a filter is applied.

  When a tape is affixed on the banknote 100, linear optical edges are detected at both edges in the width direction of the tape, that is, at the boundary between the tape and the banknote without the tape. Using this, the optical image after optical image processing for optical edge detection has a predetermined width corresponding to the width of the tape, and the linear optical edges existing in parallel are longer than the predetermined value. In the case where it is indicated, it is determined that the tape is stuck on the banknote 100 (step S22; Yes).

  On the other hand, when the optical edge by a tape is not detected, it determines with the tape not being affixed on the banknote 100 (step S22; No), Then, the thickness measurement value of the adjacent banknote 100 is compared. Then, a process for detecting the thickness detection edge is performed (step S23).

  The measured value obtained by measuring the thickness of the banknote 100 shows substantially the same value in the region where the tape is not attached. On the other hand, the area where the tape is affixed shows a larger value than the other areas by the thickness of the tape. By utilizing this, the thickness measurement edge of the tape can be detected from the change of the measurement value by comparing the adjacent thickness measurement values.

  Specifically, for example, in the banknote 100 shown in FIG. 2, the thickness of the tape is calculated by calculating the differential value of the thickness measurement value in the direction perpendicular to the transport direction, that is, the direction in which the channel for measuring the thickness of the banknote 100 changes. Detect edge detection. Similarly, the differential value of the measured value is calculated in each direction, such as a direction parallel to the transport direction, and a thickness detection edge is detected. When the measurement points whose differential value exceeds a predetermined threshold value are continuous in parallel and linearly with a predetermined width corresponding to the width of the tape and have a length equal to or longer than the predetermined value, the tape is attached to the banknote 100. (Step S24; Yes). On the other hand, when the thickness inspection edge by a tape is not detected, it determines with the tape not being affixed on the banknote 100 (step S24; No).

  As described above, in the determination process performed by detecting the edge of the tape, the process of detecting the tape based on the optical edge appearing in the infrared image (step S21) and the thickness detection appearing in the change amount of the adjacent thickness measurement value. Two processes are performed: a process of detecting a tape based on the edge (step S23). And if a tape is detected by any one process, it will determine with the tape being affixed on the banknote 100, and will determine that a tape is not affixed only when a tape is not detected by both processes. .

  When it is determined that the tape is not attached, the thickness measurement value of the entire surface of the banknote 100 is compared with the first threshold value, and the thickness determination for detecting the tape is performed (step S25). On the other hand, if it is determined that the tape is affixed, the area where the tape is affixed is identified based on the detected thickness detection edge, and the measured value of this area is compared with the second threshold value. Then, the thickness determination for detecting the tape is performed (step S26).

  Specifically, when the thickness of the banknote 100 is 100 μm, in the determination process using the first threshold, the measurement value obtained by measuring the thickness of the banknote 100 with the first threshold set to 30 μm is greater than 130 μm. The tape is affixed to the banknote 100. On the other hand, in the determination process using the second threshold value, when the second threshold value is set to 25 μm and the measurement value obtained by measuring the thickness of the banknote 100 indicates a value larger than 125 μm, it is determined that the tape is attached to the banknote 100. To do. That is, in the determination process using the second threshold value, since the tape is first detected by the edge detection process, the presence or absence of the tape is determined using the second threshold value that is stricter than the first threshold value.

  As described above, in the banknote identification device 10, only when the edge detected by the tape is detected by performing the process of detecting the optical edge from the banknote optical image and the process of detecting the thickness detection edge from the change amount of the measurement value. By determining the presence / absence of a tape with a stricter threshold, the presence / absence of a tape attached to a banknote can be determined with high accuracy.

  Next, the thickness determination process performed based on the length of the banknote 100 in the conveyance direction will be described. 7 and 8 are diagrams for explaining the thickness determination processing based on the banknote length in the transport direction. Each process described with reference to FIGS. 7 and 8 is executed by the thickness determination unit 25A. In addition, a threshold value (determination criterion) used in each process is stored in advance in the storage unit 30 as a threshold value 31B.

  In the banknote identification device 10, the thickness of the banknote 100 is measured by the thickness detection sensor 15, and the length of the banknote 100 in the transport direction (hereinafter referred to as “the bill length”) is calculated based on the measurement result of the thickness. The bill length is the number of times the thickness of the bill 100 is measured after the detection roller 15a is pushed up by the front end in the conveyance direction of the bill 100 conveyed through the conveyance path 17 until the detection roller 15a is lowered after the rear end passes ( It is calculated on the basis of the count number) and the interval (pitch) at which the thickness is measured.

  FIG. 7 is a diagram illustrating a thickness determination process based on the bill length in the transport direction. As shown in FIG. 7A, when the tape 501 is attached to the banknote 103 and reaches the gap between the detection roller 15a and the reference roller 15b, the banknote 102 to which no tape is attached is the detection roller. The timing at which the detection roller 15a is pushed up differs depending on whether it reaches between 15a and the reference roller 15b. Specifically, the thickness of the banknote 102 alone due to the displacement of the detection roller 15a is detected by a distance of ΔX, that is, a banknote conveyed at a constant speed, rather than the thickness of the banknote 103 to which the tape 501 is attached. 102 and 103 are delayed by the amount of time for which the distance of ΔX is conveyed.

  Specifically, as can be seen from an enlarged view of a part of the detection roller 15a and the reference roller 15b shown in FIG. 7B, the position where the bill 103 with the tape 501 attached contacts the roller. If it is 0 (zero), the tip of the banknote 102 does not contact the roller at this position. The banknote 102 to which the tape is not attached contacts the roller at a position further advanced by a distance of ΔX. That is, even if the banknote 102 and the banknote 103 are the banknotes of the same thickness, if the tape 501 is affixed to the banknote 103, the thickness is detected at an earlier timing than the banknote 102 of the normal thickness.

  The bill length of the bills 102 and 103 is calculated by multiplying the count number of thickness measurement and the pitch. The thickness measurement is performed at predetermined time intervals, and the distance interval (pitch) between adjacent measurement points at which the thickness measurement is performed is determined by the bill conveyance speed. In other words, the time when the bill thickness is detected and the bill conveyance speed The bill length is calculated by multiplying. Since the bill 103 with the tape 501 attached starts measuring the thickness at an earlier timing than the bill 102 with the normal thickness, the time for measuring the thickness of the bill 103 with the tape 501 attached is the bill 102 alone. It becomes longer than the time for measuring the thickness of the film. As a result, the bill length calculated based on the count value (measurement time) of the measured value is the bill 103 to which the tape 501 is attached, even though the bill 102 and the bill 103 have the same bill length. Becomes longer. That is, when the tape 501 is affixed to the bill 103, the apparent bill length in the transport direction becomes long.

  FIG. 8 is a diagram showing the banknote length in the transport direction calculated from the thickness of the banknote. 7A and 7B show a case where the front ends of the banknotes 102 and 103 enter between the detection roller 15a and the reference roller 15b, but the rear ends of the banknotes 102 and 103 pass between the rollers. Similarly, when passing, a difference occurs in the timing at which the rear end passes. For this reason, in the banknote 102 to which the tape 501 has been affixed and the banknote 103 to which the tape 501 has been affixed to the entire conveyance direction, as shown in FIG. The result is that the length is apparently longer by 2 × ΔX.

  FIG. 8B shows the bill length when the tape 501 is attached to the entire conveyance direction in the region on the banknote 103 corresponding to the channel n out of the plurality of channel roller pairs forming the thickness detection sensor 15. The calculated value is shown. In a channel that measures the thickness of the bill 103 in an area where the tape 501 is not present, the bill length of the bill 103 is L. On the other hand, when the bill 103 passes the thickness detection sensor 15, the bill length of the bill 103 is apparently longer than L by 2 × ΔX in the channel n where the tape 501 passes under the detection roller 15a. Become. When a part of the tape 501 passes under the detection roller 15a in the channel (n-1) and the channel (n + 1) adjacent to the channel n, the bill length of the banknote 103 is apparently less than L. Longer than L + 2 × ΔX.

  As shown in FIG. 8B, the thickness determination unit 25A calculates the bill length in the area corresponding to each channel based on the thickness measurement result obtained in each channel forming the thickness detection sensor 15. . Further, the thickness determination unit 25A refers to the storage unit 30 based on the previously obtained denomination identification result, and acquires the bill length (L) as the reference value. In some channels, when a bill length longer than a predetermined threshold length (L) is obtained compared to the reference bill length (L), it is determined that a tape is attached to the bill.

  As described above, in the banknote recognition apparatus 10, the thickness of the banknote is measured by the reference roller 15b and the detection roller 15a at a constant time interval and a constant distance interval, so that the rear end passes from the front end to the rear end in the banknote transport direction. Based on the number of times of measurement and the distance interval of each measurement, the length of the bill in the conveyance direction can be calculated. Based on the change in the number of times of measurement (measurement time) due to the difference in the thickness of the medium entering between the rollers, the difference in the banknote thickness is detected from the calculated banknote length, and the tape is applied. Can be determined.

  In addition, the comparison method with the threshold value quoted by the determination method mentioned above is an example, Comprising: This embodiment is not limited to this. For example, in FIG. 5 and FIG. 6, the comparison when determining the presence / absence of the tape attached to the banknote is based on the difference value obtained by subtracting the reference value of the banknote thickness from the thickness measurement value of the banknote and the threshold value. The aspect which compares the thickness measurement value of a banknote with a threshold value, without calculating | requiring a difference other than the aspect to compare may be sufficient. That is, a threshold value may be set so that the bill thickness measurement value can be directly determined, and it can be determined whether or not the difference value obtained by subtracting the bill thickness reference value from the thickness measurement value indicates the tape thickness. A threshold may be set for. Further, the comparison of bill lengths in FIG. 8B is determined by comparing the reference length of the bill obtained based on the denomination identification result and the bill length calculated from the thickness measurement result in each channel. It is not limited to the mode, and the calculated value obtained between each channel is compared regardless of the reference length of the banknote, and whether or not a banknote length longer than other channels is obtained in some channels. Based on this, it may be determined whether or not a tape is stuck on the banknote.

  As described above, according to the present embodiment, when the thickness changes due to wear in a partial region on the banknote 100, a plurality of types of templates 31A are prepared in advance according to the presence or absence of wear, After performing the process of determining the presence or absence of wear using the banknote optical image, the template 31A to be applied to the banknote 100 is selected and the thickness is determined, so the presence or absence of the tape affixed to the banknote 100 is highly accurate. Can be determined.

  Further, when the optical edge is detected using the optical image of the banknote 100 and it is determined that the detected optical edge is a tape, a threshold value that serves as a reference for determining the presence or absence of the tape is strict. Thus, the thickness can be determined. Similarly, even when the thickness detection edge is detected from the change in the measurement value obtained by measuring the thickness of the banknote 100 and it is determined that there is a tape, the thickness determination can be performed with a strict threshold. Thereby, the presence or absence of the tape affixed on the banknote 100 can be determined with high accuracy.

  Moreover, the length of the conveyance direction of the banknote 100 is calculated from the measurement result which measured the thickness of the banknote 100, and it can be determined whether the tape is affixed on the banknote 100 based on the calculated value. .

  A plurality of determination processes are executed in parallel, and if a tape is detected in one determination process, it is determined that the tape is attached to the banknote 100, whereby the tape is applied to the banknote 100. It can be determined with high accuracy whether or not it is.

  As described above, the paper sheet thickness determination method and thickness determination apparatus according to the present invention are useful for detecting a tape attached to a paper sheet with high accuracy.

DESCRIPTION OF SYMBOLS 10 Banknote identification apparatus 11, 12 Timing sensor 13 Optical line sensor 14 Fluorescence sensor 15 Thickness detection sensor 15a Detection roller 15b Reference roller 16 Magnetic sensor 17 Conveyance path 20 Control part 21 Sensor information acquisition part 22 Denomination identification part 23 Authenticity identification part 24 serial number identification unit 25 damage identification unit 25A thickness determination unit 25B comprehensive determination unit 30 storage unit

Claims (10)

A thickness determination method for determining the presence or absence of a tape body attached to a paper sheet by a thickness determination device having a thickness detection sensor and an optical line sensor,
An optical image acquisition step of acquiring a paper sheet optical image by taking an image of the paper sheet transported through the transport path with the optical line sensor;
A thickness measuring step of measuring the thickness of the paper sheet by the thickness detection sensor;
A tape body candidate detection step of detecting an optical edge on the paper sheet optical image and detecting a tape body affixed on the paper sheet based on the optical edge;
By changing the determination criteria between the case where the tape body is detected in the tape body candidate detection step and the case where the tape body is not detected, and evaluating the measurement value measured in the thickness measurement step based on the determination criterion A method for determining the thickness of a paper sheet, comprising: a first determination step for determining the presence or absence of a tape body attached to the paper sheet. The tape body candidate detection step includes
A step of detecting a thickness detection edge based on a change amount in a predetermined direction of a measured value of the thickness of the paper sheet,
It is determined that the tape body has been detected when the optical edge obtained from the optical image of the paper sheet and the thickness detection edge obtained from the amount of change in the measured value indicate the characteristics of the tape body. The paper sheet thickness determination method according to claim 1.   The criterion includes a threshold for detecting the tape body, and the threshold used when the tape body is detected is a threshold used when the tape body is not detected in order to detect a thin tape body. The sheet thickness determination method according to claim 1 or 2, wherein the thickness is set to a different value.   The paper sheet optical image used for detection of an optical edge in the tape body candidate detection step is an infrared light image. Thickness determination method. When a tape body is detected on the paper sheet optical image in the tape body candidate detection step,
5. The paper sheet thickness determination method according to claim 1, wherein, in the first determination step, only a measurement value of an area where the tape body is detected is evaluated. In order to determine the degree of wear of the paper sheet, a contamination determination step of determining the degree of contamination of the paper sheet based on the paper sheet optical image;
Different templates are selected for the case where it is determined that the paper sheet is less worn and the case where the worn paper sheet is determined to be worn in the stain determination step, and the thickness of each part of the paper sheet is indicated. And a second determination step of determining the presence or absence of a tape body attached to the paper sheet by evaluating the measurement value measured in the thickness measurement step based on the template. Item 6. The method for determining the thickness of a paper sheet according to any one of Items 1 to 5.   Thickness of a predetermined region where the thickness is changed by wear between a template selected when it is determined that the paper sheet is less worn and a template selected when it is determined that the paper sheet is worn. The paper sheet thickness determination method according to claim 6, wherein the numerical values indicating are different. Based on the timing at which the front end of the paper sheet transported through the transport path passes between the two rollers forming the thickness detection sensor and the timing at which the rear end of the paper sheet passes between the rollers. Calculating the length of the paper sheet in the conveying direction;
And a third determination step of determining whether or not a tape body is attached to the paper sheet based on the length of the paper sheet calculated in the calculation step. Item 8. A method for determining the thickness of a paper sheet according to any one of Items 1 to 7.   The thickness detection sensor is formed by a plurality of pairs of rollers arranged in a direction perpendicular to the conveying direction of the paper sheet, and the reference roller on the fixed rotation shaft and the paper sheet forming the roller pair. The thickness of the paper sheet passing between the detection roller on the rotation shaft that can be displaced in the thickness direction of the paper, and the vertical direction at a pitch of 0.25 mm in the transport direction based on the displacement amount of the detection roller 9. The sheet thickness determination method according to claim 1, wherein the thickness is measured with a resolution of 1 μm between 0 and 1023 μm. A thickness determination device for measuring the thickness of a paper sheet conveyed through a conveyance path and determining the presence or absence of a tape body attached to the paper sheet,
A thickness detection sensor for measuring the thickness of the paper sheet conveyed through the conveyance path;
An optical line sensor that captures a paper sheet optical image of the paper sheet transported through the transport path;
By performing a process of detecting a tape body attached on the paper sheet based on the optical edge detected on the paper sheet optical image, when the tape body is detected and when not detected A control unit that selects a different criterion and evaluates a measured thickness value based on the criterion to determine the presence or absence of a tape body attached to the paper sheet. Paper thickness determination device.

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