WO2016158392A1 - Paper sheet detection device and paper sheet detection method - Google Patents

Paper sheet detection device and paper sheet detection method Download PDF

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Publication number
WO2016158392A1
WO2016158392A1 PCT/JP2016/058188 JP2016058188W WO2016158392A1 WO 2016158392 A1 WO2016158392 A1 WO 2016158392A1 JP 2016058188 W JP2016058188 W JP 2016058188W WO 2016158392 A1 WO2016158392 A1 WO 2016158392A1
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WO
WIPO (PCT)
Prior art keywords
paper sheet
edge point
boundary
tape
edge
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PCT/JP2016/058188
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French (fr)
Japanese (ja)
Inventor
鵜飼　和歳
中島　明
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グローリー株式会社
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Publication of WO2016158392A1 publication Critical patent/WO2016158392A1/en

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T1/00—General purpose image data processing
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
    • G07D7/12—Visible light, infrared or ultraviolet radiation
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
    • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
    • G07D7/181—Testing mechanical properties or condition, e.g. wear or tear
    • G07D7/189—Detecting attached objects, e.g. tapes or clips

Definitions

  • the present invention relates to a paper sheet discriminating apparatus and a paper sheet discriminating method capable of discriminating whether or not a tape is stuck on a paper sheet.
  • Paper sheets such as banknotes are often folded along a short direction. When the crease breaks along the short direction, the tape may be reinforced.
  • Patent Document 1 there is a paper sheet thickness detection device disclosed in Patent Document 1 as a conventional technique capable of detecting a paper sheet to which a tape is attached in this manner.
  • the paper sheet thickness detection device disclosed in Patent Document 1 is a paper sheet that passes between a reference roller provided on a fixed rotation shaft and a detection roller provided in contact with and opposed to the reference roller. Mechanical thickness detection is performed using a detection block that rotates and displaces according to the thickness of the plate.
  • the mechanical thickness detection can only detect a tape having a thickness of 50 ⁇ m or more.
  • a thin tape such as 30 ⁇ m thickness or 40 ⁇ m thickness cannot be detected.
  • the detection device disclosed in Patent Document 2 optically detects wrinkles and tape sticking of paper sheets, not mechanical thickness detection.
  • the detection device disclosed in Patent Document 2 by irradiating light on the paper sheet obliquely from above, bright reflection at the side edge of the tape located on the light source side than the tape center or from the tape center.
  • the shadow of the side edge of the tape away from the light source is detected to detect whether the tape is affixed to the paper sheet, and it is necessary to devise the position of the light source, which complicates the structure of the device .
  • the present invention provides a paper sheet discriminating apparatus and a paper sheet discriminating method capable of discriminating whether or not a tape is stuck on a paper sheet even when a thin tape is stuck. It is intended to do.
  • a paper sheet discriminating apparatus is a paper sheet discriminating apparatus that discriminates whether a tape is affixed to a paper sheet based on a captured image of the paper sheet.
  • a storage unit for storing a reference edge point that is an edge point in a density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the paper sheet, and imaging of the paper sheet to be discriminated
  • An edge point extraction unit that extracts edge points in a density gradient direction range along a longitudinal direction of the paper sheet to be determined from an image, and an edge point extracted by the edge point extraction unit, to the reference edge point
  • a remaining edge point extracting unit that extracts a remaining edge point by removing an edge point estimated that a pixel that is not included in a captured image of the corresponding edge point and the legitimate paper sheet is generated due to a bright area; Based on the remaining edge point And it has provided an analysis unit for analyzing whether the tape is stuck to the paper sheet serving as the determination target configuration (first configuration).
  • the edge points generated due to the design of the paper sheet can be removed from the edge points that may have been generated due to the side edge of the tape.
  • the extraction of the remaining edge point as described above causes the side of the tape to move from the edge point that may have occurred due to the side edge of the tape. Edge points estimated not to be generated due to edges can be removed. Therefore, the detection accuracy of tape sticking can be increased.
  • the reference edge point is a first reference edge point that is an edge point of a first density gradient direction range included in the captured image of the legitimate paper sheet, A second reference edge point that is an edge point of the second density gradient direction range that is opposite to the first density gradient direction range, and the edge point extraction unit is configured to detect a captured image of the paper sheet to be determined. Edge points of the first density gradient direction range and edge points of the second density gradient direction range are extracted, and the remaining edge points are edge points of the first density gradient direction range extracted by the edge point extraction unit. From the first remaining edge, the edge point corresponding to the first reference edge point and the edge point estimated that the pixel not included in the captured image of the legitimate paper sheet is generated due to a bright area are removed.
  • an edge point corresponding to the second reference edge point and a pixel not included in the captured image of the legitimate paper sheet are bright areas It is preferable that the configuration includes a second remaining edge point obtained by removing an edge point estimated to have occurred due to the above (second configuration).
  • the analysis unit determines whether a tape is attached to the paper sheet to be discriminated based on the density of the remaining edge points in a predetermined size region. It is preferable that the configuration be analyzed (third configuration).
  • the predetermined size region it is possible to detect tapes with different attaching directions by changing the shape of the predetermined size region. For example, it is possible to detect a tape attached vertically (short direction of the paper sheet) by making the predetermined size area vertically long, and by tilting the predetermined size area diagonally, The affixed tape can be detected.
  • the remaining edge point extraction unit applies the captured image of the paper sheet to be determined to the captured image of the legitimate paper sheet.
  • edge points located around the thin line area are also the edge A configuration (fourth configuration) that is removed from the edge points extracted by the point extraction unit is preferable.
  • an edge point that appears due to the influence of a thin bright line generated by a strong crease can be removed from an edge point that may have occurred due to the side edge of the tape. Therefore, the detection accuracy of tape sticking can be further increased.
  • the longitudinal direction of the paper sheet to be discriminated is directed from one end to the other end. And a second boundary that changes from a first region to a second region that is darker than the first region and a third region that changes from the third region to a fourth region that is brighter than the third region.
  • the determination unit determines an interval between the first boundary and the second boundary located on the other end side with respect to the first boundary. Only in the region between the first boundary and the second boundary located on the other end side than the first boundary only when it is not less than the minimum width and not more than the maximum width of the target tape. Based on the pixel value of the pixel located, it is determined whether a tape is applied to a region between the first boundary and the second boundary located on the other end side of the first boundary. A configuration (sixth configuration) is preferable.
  • the determination unit is between the first boundary part and the second boundary part located on the other end side with respect to the first boundary part. Based on the dispersion of the pixel values of the pixels located in the region, a tape is applied to the region between the first boundary and the second boundary located on the other end side from the first boundary. It is preferable that the configuration (seventh configuration) be determined.
  • the area where the tape is affixed has little uneven density, so the dispersion of pixel values is small. Therefore, according to such a structure, the detection accuracy of tape sticking can be made high.
  • the determination unit is configured to determine the first boundary portion and the fourth region based on the pixel value of the first region and the pixel value of the fourth region. It is preferable that it is the structure (8th structure) which determines whether the tape is affixed to the area
  • a paper sheet discriminating method is a paper sheet discriminating method for discriminating whether a tape is stuck on a paper sheet based on a captured image of the paper sheet.
  • An edge point extracting step for extracting edge points in a density gradient direction range along the longitudinal direction of the paper sheet to be discriminated from a captured image of the paper sheet to be discriminated, and an edge extracted by the edge point extracting step From the point, an edge point corresponding to a reference edge point that is an edge point in a density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the legitimate paper sheet and the legitimate paper sheet
  • a remaining edge point extracting step of extracting a remaining edge point by removing an edge point estimated that a pixel not included in the captured image is generated due to a bright region, and the determination target based on the remaining edge point Become paper sheets A configuration that includes an analysis step of analyzing whether the tape is stuck.
  • the edge points generated due to the design of the paper sheet can be removed from the edge points that may have been generated due to the side edge of the tape.
  • the extraction of the remaining edge point as described above causes the side of the tape to move from the edge point that may have occurred due to the side edge of the tape. Edge points estimated not to be generated due to edges can be removed. Therefore, the detection accuracy of tape sticking can be increased.
  • the present invention even when a thin tape is stuck, it can be determined whether or not the tape is stuck on the paper sheet.
  • determination method based on this invention The block diagram which shows the structure of the paper sheet discrimination
  • the figure which shows an example of the smoothing filter The figure which shows an example of a Laplacian filter
  • the figure which shows an example of a horizontal direction Prewitt filter Diagram showing an example of a vertical Prewitt filter A flowchart showing the first estimation process Pixel value histogram for captured images of banknotes to be identified A flowchart showing the second estimation process
  • determination object The figure which shows an example of the filter for density detection
  • FIG. 1 is a diagram showing an outline of a paper sheet discrimination method according to the present invention.
  • the paper sheet discriminating method according to the present invention first, the paper sheet that is the discrimination target is irradiated with light, and the paper sheet that is the discrimination target based on the transmitted or reflected light from the paper sheet that is the discrimination target The captured image is generated (see (1) in FIG. 1).
  • edge points in the density gradient direction range along the longitudinal direction of the paper sheet to be discriminated are extracted from the captured image of the paper sheet to be discriminated (see (2) in FIG. 1).
  • the edge refers to a portion where the contrast of the image is remarkably changed.
  • the direction from the bright edge to the dark edge is the density gradient direction.
  • An edge point is a pixel corresponding to an edge in an image.
  • the longitudinal direction of the paper sheet to be discriminated with a width of ⁇ 12.5 degrees with respect to the direction from the left end to the right end of the paper sheet to be discriminated.
  • a width of ⁇ 12.5 degrees with respect to the edge point of the density gradient direction range (indicated as the A direction range in FIG. 1B) and the direction from the right edge to the left edge of the sheet to be identified
  • the edge point of the density gradient direction range (denoted as the B direction range in (2) of FIG. 1) along the longitudinal direction of the paper sheet to be discriminated is extracted.
  • a legitimate paper sheet means a paper sheet that is free from contamination such as dirt, wrinkles, and folds and is not attached with a tape.
  • Density gradient direction range along the longitudinal direction of the paper sheet to be discriminated used when extracting a specific edge point
  • a legitimate paper sheet image to be used when obtaining a reference edge point The “concentration gradient direction range along the longitudinal direction of the legitimate paper sheets included” may not completely match, but it is desirable that they completely match.
  • the edge points generated due to the design of the paper sheet can be removed from the edge points that may have been generated due to the side edge of the tape. Also, in the area where the tape is applied, the pixel becomes dark due to the influence of the tape, that is, the pixel value becomes small in this embodiment. It is possible to remove an edge point that is estimated not to have been generated due to the side edge of the tape from the edge point that may have occurred.
  • the paper sheet discrimination method in the paper sheet discrimination method according to the present invention, tape sticking is optically detected. Therefore, even when a thin tape is stuck, it can be determined whether or not the tape is stuck on the paper sheet. Further, since the bright reflection and shadow at the side edge of the tape generated by irradiating light on the paper sheet from obliquely above is not used, it is not necessary to devise the position of the light source. Furthermore, in the paper sheet discriminating method according to the present invention, due to the extraction of the remaining edge point as described above, the edge point that may have occurred due to the side edge of the tape is caused by the design of the paper sheet. The generated edge point can be removed.
  • the extraction of the remaining edge point as described above causes the tape side from the edge point that may have occurred due to the side edge of the tape. Edge points estimated not to be generated due to the edge can be removed. Therefore, the detection accuracy of tape sticking can be increased.
  • the paper sheet discriminating method according to the present invention is not limited to bills. It can also be applied to other arbitrary paper sheets such as checks, bills and gift certificates.
  • FIG. 2 is a block diagram showing the configuration of the banknote discriminating apparatus 10 according to the first embodiment of the present invention.
  • FIG. 2 only constituent elements necessary for explaining the features of the banknote discriminating apparatus 10 are shown, and descriptions of general constituent elements are omitted.
  • the bill discriminating apparatus 10 includes an image line sensor unit 1, a control unit 2, and a storage unit 3.
  • the control unit 2 includes an image data acquisition unit 2a, a denomination identification unit 2b, an edge point extraction unit 2c, a remaining edge point extraction unit 2d, and an analysis unit 2e.
  • the storage unit 3 stores a denomination identification template 3a, various filters 3b, a reference edge point 3c, and analysis standard information 3d.
  • the image line sensor unit 1 is a sensor unit that receives transmitted light or reflected light from banknotes conveyed by a conveyance mechanism (not shown), and is configured by arranging a plurality of light receiving sensors in a straight line.
  • the light applied to the banknote is preferably light having an infrared wavelength that hardly reacts to dirt, but may be visible light such as white, red, green, and blue.
  • the image line sensor unit 1 also performs a process of outputting the light reception result to the image data acquisition unit 2 b of the control unit 2.
  • the control unit 2 is a processing unit that generates image data of banknotes based on the output from the image line sensor unit 1 and analyzes the generated image data to determine whether a tape is stuck on the banknotes.
  • the image data acquisition unit 2a is a processing unit that performs processing to develop output data from the image line sensor unit 1 in a memory, synthesize it for each banknote, and generate image data for the entire banknote.
  • the image data acquisition unit 2a also performs a process of outputting the generated image data to the denomination identifying unit 2b and the edge point extracting unit 2c.
  • the denomination identifying unit 2b compares the feature pattern of the image data generated by the image data acquiring unit 2a with the denomination identifying template 3a that is a feature pattern for each denomination of the bill, and determines the denomination of the bill. To do.
  • the edge point extraction unit 2c uses various filters 3b to smooth the image data output by the image data acquisition unit 2b, and extracts edge points in the density gradient direction range along the longitudinal direction of the banknote from the smoothed image data. It is a processing part which performs the process to perform. The edge point extraction unit 2c also performs a process of outputting an edge point image indicating the extracted edge point to the remaining edge point extraction unit 2d.
  • the edge point extraction unit 2c has a concentration gradient direction range (hereinafter referred to as an A direction range) having a width of ⁇ 12.5 degrees with respect to the direction from the left end to the right end of the banknote along the longitudinal direction of the banknote.
  • Edge point and a concentration gradient direction range (hereinafter also referred to as a B direction range) along the longitudinal direction of the bill with a width of ⁇ 12.5 degrees with respect to the direction from the right end to the left end of the bill. Extract edge points.
  • the reason why the width is ⁇ 12.5 degrees is that the tape is applied obliquely. However, +12.5 degrees is an example and may be any value between 0 degrees and +45 degrees.
  • each concentration gradient direction range may not be line symmetric with respect to the longitudinal direction of the banknote, and both concentration gradient direction ranges may not be line symmetrical with respect to the short direction of the banknote.
  • either the right tape side end or the left tape side end cannot be reliably detected, but only one of the former edge point and the latter edge point may be extracted.
  • the center of the filter and the target pixel are overlapped, the filter coefficient is multiplied by the pixel value of the pixel at each overlap position, and the sum of the respective multiplication values is used as the pixel value of the target pixel. .
  • smoothing for example, a smoothing filter in which all the coefficients of 3 ⁇ 3 pixels shown in FIG. 3 are 1 can be used. By smoothing, random noise superimposed on the image can be removed. Even when smoothing is not performed, it is possible to detect edge points and density gradient directions.
  • edge points for example, a 3 ⁇ 3 pixel 8-direction Laplacian filter shown in FIG. 4 can be used.
  • a zero-cross point detected by filter processing using a Laplacian filter is an edge portion of the original image.
  • a 3 ⁇ 3 pixel horizontal Prewitt filter shown in FIG. 5 and a 3 ⁇ 3 pixel vertical Prewitt filter shown in FIG. 6 can be used.
  • Density gradient by the ratio of positive and negative combination and absolute value between pixel value of target pixel obtained by filter processing using horizontal Prewitt filter and pixel value of target pixel obtained by filter processing using vertical Prewitt filter The direction can be detected.
  • the remaining edge point extracting unit 2d is included in the edge point corresponding to the denomination reference edge point identified by the denomination identifying unit 2b from the edge point extracted by the edge point extracting unit 2c and the captured image of the valid banknote. An edge point estimated to be generated due to a region having a large pixel value that is not present is removed.
  • the remaining edge point extraction unit 2d has a thin line area with a large pixel value along the short direction of the banknote to be discriminated that is not included in the captured image of the legitimate banknote in the image data of the banknote that is discriminatively symmetric.
  • the edge points located around the thin line area are also removed from the edge points extracted by the edge point extraction unit 2c.
  • the order of removing the above three types of edge points is not particularly limited. Further, one type may be removed in order, or a plurality of types of edge points may be removed at the same time.
  • the remaining edge point extracting unit 2d is an edge point image indicating edge points in the A direction range extracted by the edge point extracting unit 2c, an image indicating reference edge points in the A direction range described later, and described later. Using the result of each estimation process, an edge point image indicating the remaining edge points in the A direction range is generated.
  • the remaining edge point extraction unit 2d includes an edge point image indicating edge points in the B direction range extracted by the edge point extraction unit 2c, an image indicating reference edge points in the B direction range described later, and estimations described later. An edge point image indicating the remaining edge points in the B direction range is generated using the processing result.
  • the remaining edge point extracting unit 2d also performs processing of outputting an edge point image indicating the remaining edge points in the A direction range and an edge point image indicating the remaining edge points in the B direction range to the analyzing unit 2e.
  • the reference edge point is an edge point appearing in legitimate banknote image data, and is used as a mask pattern of the edge point to be removed in order to extract the edge point of the tape.
  • edge points in the A direction range are detected.
  • the expansion process which expands an effective edge point to a surrounding pixel is mainly performed for the purpose of absorption of the position shift of the banknote used as a discrimination
  • the neighboring pixels may be, for example, adjacent eight neighboring pixels, or may be one neighboring pixel adjacent in the direction from the left end to the right end of the bill.
  • the effective edge point in the A direction range obtained in this way is set as the reference edge point in the A direction range.
  • the storage unit 3 stores the reference edge point in the A direction range in the form of an image showing the reference edge point in the A direction range.
  • an edge point in the B direction range is detected, and if there is an edge point at the same position with the number of determination thresholds (for example, 5) or more, B The effective edge point of the direction range.
  • the expansion process which expands an effective edge point to a surrounding pixel is mainly performed for the purpose of absorption of the position shift of the banknote used as a discrimination
  • the neighboring pixels may be, for example, adjacent eight neighboring pixels, or may be one neighboring pixel adjacent in the direction from the left end to the right end of the bill.
  • the effective edge point in the B direction range obtained in this way is set as the reference edge point in the B direction range.
  • the storage unit 3 stores the reference edge point in the B direction range in the form of an image indicating the reference edge point in the B direction range.
  • the reference edge point in the A direction range and the reference edge point in the B direction range described above differ depending on the denomination, they are stored for each denomination.
  • the reference edge point described above is created before the product shipment of the banknote discriminating apparatus 10, and the banknote discrimination apparatus 10 is shipped in a state where the reference edge point 3c is stored in the storage unit 3 in advance.
  • the creation of the reference edge point may be performed using an apparatus other than the banknote discriminating apparatus 10 or may be performed using the banknote discriminating apparatus 10 itself.
  • an interface for enabling rewriting of the contents stored in the storage unit 3 may be provided in the bill discriminating apparatus 10 so that the reference edge point 3c can be easily added or corrected.
  • the first estimation process is executed by the remaining edge point extraction unit 2d.
  • the edge point extracted by the edge point extraction unit 2c is the maximum as the target edge point processed by the first estimation process.
  • the edge points corresponding to the denomination reference edge points identified by the denomination identifying unit 2b are removed from the edge points extracted by the edge point extracting unit 2c. In this case, the remaining edge point becomes the target edge point processed by the first estimation process.
  • the remaining edge point extraction unit 2d obtains the most frequently appearing pixel value of the captured image of the banknote to be determined (step S1).
  • FIG. 8 is a diagram illustrating an example of a pixel value histogram relating to a captured image of a bill to be determined.
  • the density of the captured image of the banknote to be determined is 256 gradations
  • the pixel with a pixel value of 0 is the darkest pixel
  • the pixel with a pixel value of 256 is the brightest pixel
  • the pixel value is 188.
  • the “most frequently occurring pixel value” is used as a pixel value representing the background of the captured image of the banknote to be determined in step S2 and subsequent steps.
  • the processing after step S2 is executed for each target edge point.
  • the remaining edge point extraction unit 2d has the pixel values of the three pixels lined up successively in the direction from the right end to the left end of the banknote adjacent to the left side (the left end side of the banknote) of the target edge point.
  • the pixel value of three pixels that are smaller than the value obtained by subtracting 5 from the “most frequently appearing pixel value”, or that are adjacent to the right side of the target edge point (the right end side of the banknote) and that are successively arranged in the direction from the left end to the right end of the banknote. It is determined whether or not the first condition that each is smaller than a value obtained by subtracting 5 from the “most frequently used pixel value” (step S2).
  • the pixel value becomes smaller due to the influence of the tape. For this reason, when the first condition is satisfied, it can be estimated that the target edge point is generated due to the side edge of the tape. Therefore, when it is determined that the first condition is satisfied (YES in step S2), the remaining edge point extracting unit 2d is caused by a region having a large pixel value in which the target edge point is not included in the captured image of the valid banknote. It is estimated that the edge point is not generated (step S3).
  • the remaining edge point extraction unit 2d is adjacent to the left side of the target edge point (the left end side of the banknote) from the right end to the left end of the banknote.
  • the pixel value becomes smaller due to the influence of the tape. Therefore, when the second condition is satisfied, it can be estimated that the periphery of the target edge point is a relatively bright background and the target edge point is generated due to the side edge of the tape. Therefore, when it is determined that the second condition is satisfied (YES in step S4), the remaining edge point extraction unit 2d is caused by a region having a large pixel value in which the target edge point is not included in the captured image of the valid banknote. It is estimated that the edge point is not generated (step S3).
  • step S4 when neither the first condition nor the second condition is satisfied, it is unlikely that the target edge point has occurred due to the side edge of the tape. Therefore, when it is not determined that the second condition is satisfied (NO in step S4), the remaining edge point extraction unit 2d has a large pixel value where the target edge point is not included in the captured image of the valid banknote. It is estimated that the edge point is generated due to (step S5).
  • determination conditions used in steps S2 and S4 are merely examples, and the threshold values used in the determination conditions are not particularly limited.
  • the second estimation process to be estimated will be described using the flowchart of FIG.
  • the second estimation process is executed by the remaining edge point extraction unit 2d.
  • the remaining edge point extraction unit 2d obtains the most frequently appearing pixel value of the captured image of the banknote to be discriminated (step S11).
  • the process of step S11 is the same as the process of step S1 in the flowchart of FIG.
  • the remaining edge point extraction unit 2d determines the average value of the pixel values in the vertical direction (short direction of the banknote) for each captured pixel image in the horizontal direction (longitudinal direction of the banknote). (Step S12).
  • An example of the calculation result obtained by the process of step S12 is represented as a graph in FIG.
  • Condition (I) is a condition in which at least one of the average values of the three vertical pixel values is larger than the most frequent pixel value in the three horizontal width pixels to be determined.
  • Condition (II) is a condition that the average value of the vertical pixel values at the left end of the three horizontal pixels to be determined is 5 or more larger than the average value of the vertical pixel values adjacent to the left side.
  • Condition (III) is a condition that the average value of the vertical pixel values at the right end of the three horizontal pixels to be determined is 5 or more larger than the average value of the vertical pixel values adjacent to the right. .
  • the remaining edge point extraction unit 2d has a width of 3 pixels that is the determination target in step S13.
  • the bright vertical thin line means a thin linear region having a large pixel value along the short direction of the banknote to be determined that is not included in the captured image of the legitimate banknote. This bright vertical line is generated by a strong crease.
  • the remaining edge point extraction unit 2d is the horizontal direction that is the determination target in step S13. It is estimated that the width of 3 pixels is not a bright vertical thin line (step S15).
  • step S13 onward is repeated while sliding the horizontal width of 3 pixels, which is the determination target in step S13, in the horizontal direction one pixel at a time.
  • the edge points included in the bright vertical thin line and one pixel on both sides thereof are extracted by the edge point extracting unit 2c. Removed from.
  • an edge point appearing by a thin line-shaped region having a large pixel value along the short direction of the banknote to be discriminated that is not included in the captured image of the valid banknote is erroneously determined as an edge point by the side edge of the tape. It is possible to prevent detection.
  • each determination condition used in step S13 is merely an example, and the threshold value used in the determination condition is not particularly limited.
  • the above-described second estimation process can be performed independently regardless of the detection of tape sticking.
  • it has a function of detecting a strong broken line (strong broken line).
  • the analysis unit 2e synthesizes the edge point image indicating the remaining edge point in the A direction range and the edge point image indicating the remaining edge point in the B direction range sent from the remaining edge point extracting unit 2d, and the synthesized image Then, a density detection filter is applied to detect the density of remaining edge points in a predetermined size region as a pixel value.
  • the analysis unit 2e detects the side edge of the tape when the density of remaining edge points in a predetermined size area detected as a pixel value exceeds a threshold value stored in the storage unit 3 as analysis reference information 3d. In this embodiment, both the right tape side edge and the left tape side edge are detected. For this reason, even if one of the right tape side edge and the left tape side edge is in a position where it overlaps with the thread portion of the banknote, the other tape side edge can be detected, and tape sticking can be detected. it can.
  • the predetermined size region is formed in a vertically long shape, for example, the density detection filter shown in FIG. 11 can be used, and when the predetermined size region is formed in an inclined shape, for example, the density detection filter shown in FIG. Can be used.
  • the predetermined size area vertically long, it is possible to detect tapes that are stuck vertically (short direction of the paper), and by making the predetermined size area inclined diagonally, the tape is attached obliquely. The detected tape can be detected.
  • the side edge of the tape is detected independently without combining the edge point image indicating the remaining edge point in the A direction range and the edge point image indicating the remaining edge point in the B direction range. You may make it do.
  • detection of the right side edge of the right tape and detection of the left side edge of the left tape can be performed separately. For example, even if one of the right side tape side end and the left side tape side end overlaps the bill thread portion, the other tape side end can be detected, and the other tape side end Since it can be grasped whether it is a right tape side edge or a left tape side edge, a tape sticking can be detected and a tape sticking position can be estimated.
  • the banknote discriminating apparatus 10 extracts an edge point and discriminates whether or not a tape is stuck on the banknote. However, it is also assumed that the edge generated by the side edge of the affixed tape is not clear. For this reason, it is desirable to be able to detect that the tape is stuck on the banknote without extracting the edge point.
  • the bill discriminating apparatus 20 has a function capable of detecting that the tape is stuck on the bill without extracting the edge point, according to the first embodiment of the present invention.
  • the configuration is added to the apparatus 10.
  • FIG. 13 is a block diagram showing a configuration of the bill discriminating apparatus 20.
  • the same parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
  • the control unit 2 of the bill discriminating apparatus 20 includes a boundary detection unit 2f and a determination unit in addition to the image data acquisition unit 2a, denomination identification unit 2b, edge point extraction unit 2c, remaining edge point extraction unit 2d, and analysis unit 2e. 2g.
  • the storage unit 3 stores detection standard information 3e and determination standard information 3f in addition to the denomination identification template 3a, various filters 3b, reference edge points 3c, and analysis standard information 3d.
  • the boundary detection unit 2f uses the image data generated by the image data acquisition unit 2a and is darker than the first region from the first region in the direction from one end to the other end in the longitudinal direction of the bill to be determined. A first boundary portion that is a boundary that changes to the second region and a second boundary portion that is a boundary that changes from the third region to the fourth region that is brighter than the third region are detected.
  • one end in the longitudinal direction of the banknote to be discriminated is set as the left end of the banknote, and the other end in the longitudinal direction of the banknote to be discriminated is set as the right end of the banknote. Can be obtained.
  • the boundary detection unit 2f sets a point of interest 4 corresponding to a height of 2 pixels in the horizontal direction in the captured image of the banknote to be discriminated, and sets a left side region 5 of 4 ⁇ 2 pixels adjacent to the left side of the point of interest 4.
  • the right region 6 of 4 ⁇ 2 pixels adjacent to the right side of the point of interest is set (step S21). Therefore, the positional relationship among the point of interest 4, the left region 5, and the right region 6 is as shown in FIG.
  • the number of constituent pixels of each of the point of interest 4, the left region 5, and the right region 6 is not particularly limited. However, the edge point generated by the bill design is prevented from entering each of the point of interest 4, the left region 5, and the right region 6. There is a need.
  • a banknote having no symbol in the vicinity of the upper end is set as a determination target, and the target point 4 is set so that the target point 4 slides in the horizontal direction in the vicinity of the upper end without the symbol.
  • the vertical position of the point of interest 4 is changed according to the horizontal direction of the banknote using the denomination identification template 3a or the like so that the point of interest 4, the left region 5 and the right region 6 do not cover the design of the banknote.
  • the boundary detection unit 2f determines whether or not the point of interest 4 corresponds to “a first boundary that is a boundary where the first region changes to a second region darker than the first region” (step S22). ). In the determination in step S22, if the left region 5 is a bright region and the right region 6 is a dark region, the point of interest 4 corresponds to the first boundary.
  • the storage unit 3 may store the predetermined value and the determination formula used in the determination in step S22 as the detection reference information 3e.
  • the point of interest 4 corresponds to the first boundary.
  • the central pixel value of the left region 5 is larger than the central pixel value of the right region 6 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the first boundary.
  • the average pixel value of the left area 5 is larger than the average pixel value of the right area 6 by a predetermined value or Even when the central pixel value of the region 5 is larger than the central pixel value of the right region 6 by a predetermined value or more, if the variance of the pixel values of the right region 6 is not less than the predetermined value, the point of interest 4 becomes the first boundary. You may determine that it does not apply.
  • the boundary detection unit 2f When it is determined that the point of interest 4 corresponds to “a first boundary portion that is a boundary where the first region changes to a second region that is darker than the first region” (YES in step S22), the boundary detection unit 2f The point of interest 4 is set as the first boundary (step S23).
  • step S24 when it is determined that the point of interest 4 does not correspond to the “first boundary portion that is a boundary changing from the first region to the second region darker than the first region” (NO in step S22), the point of interest 4 is It is determined whether or not a “second boundary portion that is a boundary changing from the third region to the fourth region brighter than the third region” is satisfied (step S24). In the determination of step S24, if the left area 5 is a dark area and the right area 6 is a bright area, the point of interest 4 corresponds to the second boundary.
  • the storage unit 3 may store the predetermined value and the determination formula used in the determination in step S24 as the detection reference information 3e.
  • the average pixel value of the right area 6 is larger than the average pixel value of the left area 5 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the second boundary.
  • the central pixel value of the right region 6 is larger than the central pixel value of the left region 5 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the second boundary.
  • the average pixel value in the right area 6 is larger than the average pixel value in the left area 5 by a predetermined value or on the right side.
  • the attention point 4 becomes the second boundary. You may determine that it does not apply.
  • the boundary detection unit 2f The point of interest 4 is set as the second boundary (step S25).
  • the boundary detection process described above is repeated while the point of interest 4 is slid horizontally by one pixel.
  • the boundary detection unit 2f outputs information on the first boundary and the second boundary determined in steps S23 and S25 to the determination unit 2g.
  • the determination unit 2g uses the first boundary part and the second boundary part detected by the boundary part detection part 2f, and is between the first boundary part and the second boundary part located on the right side of the first boundary part. Based on the pixel value of the pixel located in the area, it is determined whether or not the tape is applied to the area between the first boundary and the second boundary located on the right side of the first boundary.
  • Determination processing executed by the determination unit 2g will be described with reference to the flowchart of FIG.
  • the determination unit 2g selects a combination of the first boundary and the second boundary that can be a combination of the left tape side end and the right tape side end from all combinations of the first boundary portion and the second boundary portion. Extract (step S31).
  • a combination of the first boundary and the second boundary located on the right side of the first boundary is extracted, and further the second boundary located on the right side of the first boundary and the first boundary. Extraction is limited to combinations in which the interval between the parts is not less than the minimum width of the tape to be determined and not more than the maximum width.
  • the combination of the first boundary portion and the second boundary portion is narrowed down in consideration of the width of the tape to be determined, so that the determination time can be shortened and erroneous detection can be prevented.
  • the determination unit 2g pays attention to a certain combination from the combinations extracted in step S31, and determines whether or not the focused first and second boundary portions correspond to the tape application portion ( Step S32).
  • the storage unit 3 may store the predetermined value and the determination formula used in the determination in step S32 as the determination reference information 3f.
  • a tape is applied between the first boundary and the second boundary. Can be determined to fall under the category.
  • the tape between the focused first boundary and the second boundary is tape. It can be determined that it corresponds to the pasting part.
  • the variance of the pixel values in the region between the first boundary and the second boundary is less than a predetermined value, the area between the first boundary and the second boundary is the tape application portion. It can be determined that this is the case.
  • the background pixel values of the banknotes to be discriminated are not uniform. Then, since the pixel value distribution when the tape is affixed to a place where the background density is not uniform is as shown in FIG. 17, if the detection conditions of the first boundary and the second boundary are strict, the first boundary or There is a possibility that the second boundary may not be detected. On the other hand, if the detection conditions at the first boundary and the second boundary are relaxed, the first boundary and the pixel value distribution when the background density is not uniform as shown in FIG. The second boundary will be detected.
  • the average pixel value of the left region 5 shown in FIG. 15 corresponding to the focused first boundary and the right side shown in FIG. 15 corresponding to the focused second boundary is obtained, and a value obtained by subtracting “the average pixel value of the pixels located in the region between the first boundary portion and the second boundary portion of interest” from the sum is obtained.
  • the obtained value is less than the predetermined value
  • the average pixel value of the pixels located in the region between the first boundary portion and the second boundary portion of interest is less than the predetermined value or the first of interest. Even if the central pixel value of the pixel located in the area between the boundary and the second boundary is less than the predetermined value, the area between the first boundary and the second boundary that is focused on corresponds to the tape application part You may decide not to.
  • the determination unit 2g determines the distance between the focused first boundary and the second boundary. Let it be a tape application part (step S33).
  • step S32 when it is determined that the area between the focused first boundary and the second boundary does not correspond to the tape application part (NO in step S32), the flow is ended as it is.
  • step S32 is repeated, and the determination in step S32 is performed for all combinations extracted in step S31.
  • the boundary detection processing and determination processing described above can determine whether the tape is applied without extracting the edge point, so even if the edge generated by the side edge of the applied tape is not clear It is possible to detect that the tape is stuck on the leaves.
  • the determination is performed in consideration of the pixel value distribution in any of the above-described steps S22, S24, and S32. Accordingly, it is possible to prevent erroneous detection of contamination such as ink bleeding as tape sticking.
  • the bill discriminating device 20 has a function capable of detecting that the tape is stuck on the bill by extracting the edge point, and a function capable of detecting that the tape is stuck on the bill without extracting the edge point.
  • the function that can detect that the tape is stuck on the banknote without extracting the edge point explained in detail in the present embodiment is that the edge point is extracted and the tape is stuck on the banknote. It is also possible to carry out the function independently regardless of the function that can detect that it has been detected.
  • the function which can detect that the tape is affixed on a banknote, and a mechanical thickness detection are performed, and it detects that the tape is affixed You may implement in combination with the function which can be performed.
  • the front edge of the paper sheet is larger than the original thickness due to the impact when entering the thickness sensor Since the thickness is detected, there is a problem that it is not possible to determine whether or not the tape is stuck on the front end portion of the paper sheet even if it is not a thin tape.

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Abstract

Provided is a paper sheet detection device provided with a recording unit, an edge point extraction unit, a residual edge point extraction unit, and an analysis unit. The recording unit records reference edge points, which are edge points in a density gradient direction range along the longitudinal direction of a valid paper sheet included in a captured image of the valid paper sheet. The edge point extraction unit extracts edge points in a density gradient direction range along the longitudinal direction of the paper sheet being detected, from a captured image of the paper sheet being detected. The residual edge point extraction unit removes, from the edge points extracted by the edge point extraction unit, edge points corresponding to the reference edge points and edge points presumed to occur when pixels not included in the captured image of the valid paper sheet are generated by a bright region, and extracts residual edge points. The analysis unit analyzes, on the basis of the residual edge points, whether or not a tape is affixed to the paper sheet being detected.

Description

紙葉類判別装置及び紙葉類判別方法Paper sheet discriminating apparatus and paper sheet discriminating method
　本発明は、紙葉類にテープが貼られているか否かを判別することができる紙葉類判別装置及び紙葉類判別方法に関する。 The present invention relates to a paper sheet discriminating apparatus and a paper sheet discriminating method capable of discriminating whether or not a tape is stuck on a paper sheet.
　紙幣等の紙葉類は短手方向に沿って折り目を入れて折り畳まれることが多い。そして、この折り目によって短手方向に沿った破れが生じた場合にテープによって補強されることがある。 Paper sheets such as banknotes are often folded along a short direction. When the crease breaks along the short direction, the tape may be reinforced.
　このようにしてテープが貼られた紙葉類を検知することができる従来技術として、例えば特許文献１で開示されている紙葉類の厚さ検出装置がある。 For example, there is a paper sheet thickness detection device disclosed in Patent Document 1 as a conventional technique capable of detecting a paper sheet to which a tape is attached in this manner.
　特許文献１で開示されている紙葉類の厚さ検出装置は、固定された回転軸に設けられた基準ローラと基準ローラに対向接触して設けられた検知ローラとの間を通る紙葉類の厚さに応じて回動変位する検知ブロックを用いた機械式の厚み検知を行っている。 The paper sheet thickness detection device disclosed in Patent Document 1 is a paper sheet that passes between a reference roller provided on a fixed rotation shaft and a detection roller provided in contact with and opposed to the reference roller. Mechanical thickness detection is performed using a detection block that rotates and displaces according to the thickness of the plate.
特許第４８１９１６２号公報Japanese Patent No. 4819162 米国特許第８０８９０４５号明細書US Patent No. 8089045
　しかしながら、機械式の厚み検知では５０μｍ以上の厚みを有するテープしか検知することができず、例えば３０μｍ厚や４０μｍ厚といった薄いテープを検出することができないという問題があった。 However, the mechanical thickness detection can only detect a tape having a thickness of 50 μm or more. For example, a thin tape such as 30 μm thickness or 40 μm thickness cannot be detected.
　一方、特許文献２で開示されている検知装置は、機械式の厚み検知ではなく紙葉類のしわやテープ貼付を光学的に検知している。しかしながら、特許文献２で開示されている検知装置では、紙葉類に対して斜め上方から光を照射することで、テープ中央よりも光源側に位置するテープ側方端の明るい反射やテープ中央よりも光源から離れているテープ側方端の影を検出して紙葉類にテープが貼られているかを検知しており、光源の位置を工夫する必要があるため、機器の構造が複雑になる。 On the other hand, the detection device disclosed in Patent Document 2 optically detects wrinkles and tape sticking of paper sheets, not mechanical thickness detection. However, in the detection device disclosed in Patent Document 2, by irradiating light on the paper sheet obliquely from above, bright reflection at the side edge of the tape located on the light source side than the tape center or from the tape center. In addition, the shadow of the side edge of the tape away from the light source is detected to detect whether the tape is affixed to the paper sheet, and it is necessary to devise the position of the light source, which complicates the structure of the device .
　本発明は、上記の状況に鑑み、薄いテープが貼られている場合でも紙葉類にテープが貼られているか否かを判別することができる紙葉類判別装置及び紙葉類判別方法を提供することを目的とするものである。 In view of the above situation, the present invention provides a paper sheet discriminating apparatus and a paper sheet discriminating method capable of discriminating whether or not a tape is stuck on a paper sheet even when a thin tape is stuck. It is intended to do.
　上記目的を達成するために本発明に係る紙葉類判別装置は、紙葉類の撮像画像に基づいて紙葉類にテープが貼られているかを判別する紙葉類判別装置であって、正当な紙葉類の撮像画像に含まれる前記正当な紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点である参照エッジ点を記憶する記憶部と、判別対象となる紙葉類の撮像画像から前記判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点を抽出するエッジ点抽出部と、前記エッジ点抽出部によって抽出されたエッジ点から、前記参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いて残存エッジ点を抽出する残存エッジ点抽出部と、前記残存エッジ点に基づいて前記判別対象となる紙葉類にテープが貼られているかを解析する解析部とを備えた構成（第１の構成）とする。 In order to achieve the above object, a paper sheet discriminating apparatus according to the present invention is a paper sheet discriminating apparatus that discriminates whether a tape is affixed to a paper sheet based on a captured image of the paper sheet. A storage unit for storing a reference edge point that is an edge point in a density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the paper sheet, and imaging of the paper sheet to be discriminated An edge point extraction unit that extracts edge points in a density gradient direction range along a longitudinal direction of the paper sheet to be determined from an image, and an edge point extracted by the edge point extraction unit, to the reference edge point A remaining edge point extracting unit that extracts a remaining edge point by removing an edge point estimated that a pixel that is not included in a captured image of the corresponding edge point and the legitimate paper sheet is generated due to a bright area; Based on the remaining edge point And it has provided an analysis unit for analyzing whether the tape is stuck to the paper sheet serving as the determination target configuration (first configuration).
　このような構成によると、テープ貼付を光学的に検知しているので、薄いテープが貼られている場合でも紙葉類にテープが貼られているか否かを判別することができる。また、紙葉類に対して斜め上方から光を照射することで発生するテープ側方端の明るい反射や影を利用しないので、光源の位置を工夫する必要がない。したがって、機器の構造を簡単にすることができる。 According to such a configuration, since the tape sticking is optically detected, it is possible to determine whether or not the tape is stuck on the paper sheet even when a thin tape is stuck. Further, since the bright reflection and shadow at the side edge of the tape generated by irradiating light on the paper sheet from obliquely above is not used, it is not necessary to devise the position of the light source. Therefore, the structure of the device can be simplified.
　また、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点から紙葉類の図柄に起因して発生したエッジ点を取り除くことができる。また、テープが貼付された領域ではテープの影響によって画素が暗くなるため、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点からテープ側方端に起因して発生していないと推定したエッジ点を取り除くことができる。したがって、テープ貼付の検知精度を高くすることができる。 Also, by extracting the remaining edge points as described above, the edge points generated due to the design of the paper sheet can be removed from the edge points that may have been generated due to the side edge of the tape. In addition, because the pixels are darkened due to the influence of the tape in the area where the tape is applied, the extraction of the remaining edge point as described above causes the side of the tape to move from the edge point that may have occurred due to the side edge of the tape. Edge points estimated not to be generated due to edges can be removed. Therefore, the detection accuracy of tape sticking can be increased.
　上記第１の構成の紙葉類判別装置において、前記参照エッジ点は、前記正当な紙葉類の撮像画像に含まれる第１濃度勾配方向範囲のエッジ点である第１参照エッジ点と、前記第１濃度勾配方向範囲と逆方向である第２濃度勾配方向範囲のエッジ点である第２参照エッジ点とを含み、前記エッジ点抽出部は、前記判別対象となる紙葉類の撮像画像から前記第１濃度勾配方向範囲のエッジ点および前記第２濃度勾配方向範囲のエッジ点を抽出し、前記残存エッジ点は、前記エッジ点抽出部によって抽出された前記第１濃度勾配方向範囲のエッジ点から、前記第１参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いた第１残存エッジ点と、前記エッジ点抽出部によって抽出された前記第２濃度勾配方向範囲のエッジ点から、前記第２参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いた第２残存エッジ点とを含む構成（第２の構成）であることが好ましい。 In the paper sheet discriminating apparatus having the first configuration, the reference edge point is a first reference edge point that is an edge point of a first density gradient direction range included in the captured image of the legitimate paper sheet, A second reference edge point that is an edge point of the second density gradient direction range that is opposite to the first density gradient direction range, and the edge point extraction unit is configured to detect a captured image of the paper sheet to be determined. Edge points of the first density gradient direction range and edge points of the second density gradient direction range are extracted, and the remaining edge points are edge points of the first density gradient direction range extracted by the edge point extraction unit. From the first remaining edge, the edge point corresponding to the first reference edge point and the edge point estimated that the pixel not included in the captured image of the legitimate paper sheet is generated due to a bright area are removed. Point and before From the edge point of the second density gradient direction range extracted by the edge point extraction unit, an edge point corresponding to the second reference edge point and a pixel not included in the captured image of the legitimate paper sheet are bright areas It is preferable that the configuration includes a second remaining edge point obtained by removing an edge point estimated to have occurred due to the above (second configuration).
　このような構成によると、右側テープ側方端および左側テープ側方端それぞれの検知が可能となり、テープ貼付の検知精度をより一層高くすることができる。 According to such a configuration, it is possible to detect the side end of the right tape and the side end of the left tape, and it is possible to further increase the accuracy of detecting the tape sticking.
　上記第１または第２の構成の紙葉類判別装置において、前記解析部は、所定サイズ領域における前記残存エッジ点の密度に基づいて前記判別対象となる紙葉類にテープが貼られているかを解析する構成（第３の構成）であることが好ましい。 In the paper sheet discriminating apparatus having the first or second configuration, the analysis unit determines whether a tape is attached to the paper sheet to be discriminated based on the density of the remaining edge points in a predetermined size region. It is preferable that the configuration be analyzed (third configuration).
　このような構成によると、所定サイズ領域の形状を変えることで貼り付け向きの異なるテープを検知することができる。例えば所定サイズ領域を縦長形状にすることで縦（紙葉類の短手方向）に貼付されたテープを検知することができ、所定サイズ領域を斜めに傾いた形状にすることで斜めに傾いて貼付されたテープを検知することができる。 According to such a configuration, it is possible to detect tapes with different attaching directions by changing the shape of the predetermined size region. For example, it is possible to detect a tape attached vertically (short direction of the paper sheet) by making the predetermined size area vertically long, and by tilting the predetermined size area diagonally, The affixed tape can be detected.
　上記第１～第３のいずれかの構成の紙葉類判別装置において、前記残存エッジ点抽出部は、前記判別対象となる紙葉類の撮像画像に、前記正当な紙葉類の撮像画像に含まれていない前記判別対象となる紙葉類の短手方向に沿った画素が明るい細線状領域が存在していると推定した場合に、前記細線状領域の周囲に位置するエッジ点も前記エッジ点抽出部によって抽出されたエッジ点から取り除く構成（第４の構成）であることが好ましい。 In the paper sheet discriminating apparatus having any one of the first to third configurations, the remaining edge point extraction unit applies the captured image of the paper sheet to be determined to the captured image of the legitimate paper sheet. When it is presumed that there is a bright thin line area where pixels along the short direction of the paper sheet to be discriminated that are not included are included, edge points located around the thin line area are also the edge A configuration (fourth configuration) that is removed from the edge points extracted by the point extraction unit is preferable.
　このような構成によると、テープ側方端に起因して発生した可能性があるエッジ点から、強い折り目によって発生した細い明線の影響で現れたエッジ点を取り除くことができる。したがって、テープ貼付の検知精度をより一層高くすることができる。 According to such a configuration, an edge point that appears due to the influence of a thin bright line generated by a strong crease can be removed from an edge point that may have occurred due to the side edge of the tape. Therefore, the detection accuracy of tape sticking can be further increased.
　上記第１～第４のいずれかの構成の紙葉類判別装置において、前記判別対象となる紙葉類の撮像画像において、前記判別対象となる紙葉類の長手方向の一端から他端に向かう方向で、第１領域から前記第１領域よりも暗い第２領域に変化する境である第１境部および第３領域から前記第３領域よりも明るい第４領域に変化する境である第２境部を検知する検知部と、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域に位置する画素の画素値に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定する判定部とを備えた構成（第５の構成）であることが好ましい。 In the paper sheet discriminating apparatus having any one of the first to fourth configurations, in the captured image of the paper sheet to be discriminated, the longitudinal direction of the paper sheet to be discriminated is directed from one end to the other end. And a second boundary that changes from a first region to a second region that is darker than the first region and a third region that changes from the third region to a fourth region that is brighter than the third region. Based on a pixel value of a pixel located in a region between a detection unit that detects a boundary part, and the second boundary part that is located on the other end side of the first boundary part and the first boundary part, A configuration including a determination unit that determines whether a tape is applied to a region between the first boundary and the second boundary located on the other end side of the first boundary (fifth) It is preferable that
　このような構成によると、エッジ点を抽出せずにテープが貼られているかを判定することができるので、貼付されたテープの側方端によって発生するエッジが鮮明でない場合でも紙葉類にテープが貼られていることを検知することができる。 According to such a configuration, it is possible to determine whether the tape is applied without extracting the edge point, so even if the edge generated by the side edge of the applied tape is not clear, the tape is applied to the paper sheet. Can be detected.
　上記第５の構成の紙葉類判別装置において、前記判定部は、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の間隔が判定対象であるテープの最小幅以上であり最大幅以下である場合にのみ、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域に位置する画素の画素値に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定する構成（第６の構成）であることが好ましい。 In the paper sheet discriminating apparatus having the fifth configuration, the determination unit determines an interval between the first boundary and the second boundary located on the other end side with respect to the first boundary. Only in the region between the first boundary and the second boundary located on the other end side than the first boundary only when it is not less than the minimum width and not more than the maximum width of the target tape. Based on the pixel value of the pixel located, it is determined whether a tape is applied to a region between the first boundary and the second boundary located on the other end side of the first boundary. A configuration (sixth configuration) is preferable.
　このような構成によると、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との全ての組合せを判定せず、判定する組合せを判定対象であるテープの幅を考慮して絞り込むので、判定時間の短縮や誤検知の防止を図ることができる。 According to such a configuration, all combinations of the first boundary portion and the second boundary portion located on the other end side than the first boundary portion are not determined, and the combination to be determined is a determination target. Since narrowing is performed in consideration of the width of the tape, determination time can be shortened and erroneous detection can be prevented.
　上記第５または第６の構成の紙葉類判別装置において、前記判定部は、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域に位置する画素の画素値の分散に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定する構成（第７の構成）であることが好ましい。 In the paper sheet discriminating apparatus having the fifth or sixth configuration, the determination unit is between the first boundary part and the second boundary part located on the other end side with respect to the first boundary part. Based on the dispersion of the pixel values of the pixels located in the region, a tape is applied to the region between the first boundary and the second boundary located on the other end side from the first boundary. It is preferable that the configuration (seventh configuration) be determined.
　テープが貼られている領域は濃度むらが小さいので、画素値の分散が小さくなる。したがって、このような構成によると、テープ貼付の検知精度を高くすることができる。 The area where the tape is affixed has little uneven density, so the dispersion of pixel values is small. Therefore, according to such a structure, the detection accuracy of tape sticking can be made high.
　上記第５～第７のいずれかの構成の紙葉類判別装置において、前記判定部は、前記第１領域の画素値および前記第４領域の画素値に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定する構成（第８の構成）であることが好ましい。 In the paper sheet discriminating apparatus having any one of the fifth to seventh configurations, the determination unit is configured to determine the first boundary portion and the fourth region based on the pixel value of the first region and the pixel value of the fourth region. It is preferable that it is the structure (8th structure) which determines whether the tape is affixed to the area | region between the said 2nd boundary part located in the said other end side rather than a 1st boundary part.
　このような構成によると、第１境部および第２境部を検知する条件を緩く設定することができるので、判別対象となる紙葉類の背景濃度が一様でない場合でもテープの貼付を検知することができる。 According to such a configuration, since the conditions for detecting the first boundary and the second boundary can be set loosely, even when the background density of the paper sheet to be discriminated is not uniform, tape sticking is detected. can do.
　上記目的を達成するために本発明に係る紙葉類判別方法は、紙葉類の撮像画像に基づいて紙葉類にテープが貼られているかを判別する紙葉類判別方法であって、判別対象となる紙葉類の撮像画像から前記判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点を抽出するエッジ点抽出工程と、前記エッジ点抽出工程によって抽出されたエッジ点から、正当な紙葉類の撮像画像に含まれる前記正当な紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点である参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いて残存エッジ点を抽出する残存エッジ点抽出工程と、前記残存エッジ点に基づいて前記判別対象となる紙葉類にテープが貼られているかを解析する解析工程とを備えた構成とする。 In order to achieve the above object, a paper sheet discriminating method according to the present invention is a paper sheet discriminating method for discriminating whether a tape is stuck on a paper sheet based on a captured image of the paper sheet. An edge point extracting step for extracting edge points in a density gradient direction range along the longitudinal direction of the paper sheet to be discriminated from a captured image of the paper sheet to be discriminated, and an edge extracted by the edge point extracting step From the point, an edge point corresponding to a reference edge point that is an edge point in a density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the legitimate paper sheet and the legitimate paper sheet A remaining edge point extracting step of extracting a remaining edge point by removing an edge point estimated that a pixel not included in the captured image is generated due to a bright region, and the determination target based on the remaining edge point Become paper sheets A configuration that includes an analysis step of analyzing whether the tape is stuck.
　このような構成によると、テープ貼付を光学的に検知しているので、薄いテープが貼られている場合でも紙葉類にテープが貼られているか否かを判別することができる。また、紙葉類に対して斜め上方から光を照射することで発生するテープ側方端の明るい反射や影を利用しないので、光源の位置を工夫する必要がない。したがって、上記の紙葉類判別方法構造の実施が容易になる。 According to such a configuration, since the tape sticking is optically detected, it is possible to determine whether or not the tape is stuck on the paper sheet even when a thin tape is stuck. Further, since the bright reflection and shadow at the side edge of the tape generated by irradiating light on the paper sheet from obliquely above is not used, it is not necessary to devise the position of the light source. Therefore, it becomes easy to implement the above-described paper sheet discrimination method structure.
　また、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点から紙葉類の図柄に起因して発生したエッジ点を取り除くことができる。また、テープが貼付された領域ではテープの影響によって画素が暗くなるため、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点からテープ側方端に起因して発生していないと推定したエッジ点を取り除くことができる。したがって、テープ貼付の検知精度を高くすることができる。 Also, by extracting the remaining edge points as described above, the edge points generated due to the design of the paper sheet can be removed from the edge points that may have been generated due to the side edge of the tape. In addition, because the pixels are darkened due to the influence of the tape in the area where the tape is applied, the extraction of the remaining edge point as described above causes the side of the tape to move from the edge point that may have occurred due to the side edge of the tape. Edge points estimated not to be generated due to edges can be removed. Therefore, the detection accuracy of tape sticking can be increased.
　本発明によると、薄いテープが貼られている場合でも紙葉類にテープが貼られているか否かを判別することができる。 According to the present invention, even when a thin tape is stuck, it can be determined whether or not the tape is stuck on the paper sheet.
本発明に係る紙葉類判別手法の概要を示す図The figure which shows the outline | summary of the paper sheet discrimination | determination method based on this invention 本発明の第１実施形態に係る紙葉類判別装置の構成を示すブロック図The block diagram which shows the structure of the paper sheet discrimination | determination apparatus which concerns on 1st Embodiment of this invention. 平滑化フィルタの一例を示す図The figure which shows an example of the smoothing filter ラプラシアンフィルタの一例を示す図The figure which shows an example of a Laplacian filter 横方向Prewittフィルタの一例を示す図The figure which shows an example of a horizontal direction Prewitt filter 縦方向Prewittフィルタの一例を示す図Diagram showing an example of a vertical Prewitt filter 第１の推定処理を示すフローチャートA flowchart showing the first estimation process 判別対象となる紙幣の撮像画像に関する画素値ヒストグラムPixel value histogram for captured images of banknotes to be identified 第２の推定処理を示すフローチャートA flowchart showing the second estimation process 判別対象となる紙幣の撮像画像に関する短手方向の平均画素値を示す図The figure which shows the average pixel value of the transversal direction regarding the captured image of the banknote used as discrimination | determination object 密度検出用フィルタの一例を示す図The figure which shows an example of the filter for density detection 密度検出用フィルタの他の例を示す図The figure which shows the other example of the filter for density detection 本発明の第２実施形態に係る紙葉類判別装置の構成を示すブロック図The block diagram which shows the structure of the paper sheet discrimination | determination apparatus concerning 2nd Embodiment of this invention. 境部検知処理を示すフローチャートFlow chart showing boundary detection processing 着目点、左側領域、および右側領域の配置を示す図Diagram showing the arrangement of the point of interest, the left area, and the right area 判定処理を示すフローチャートFlow chart showing determination processing 背景濃度が一様でない場所にテープが貼付された場合の画素値分布を模式的に示す図The figure which shows typically pixel value distribution when the tape is stuck on the place where background density is not uniform 背景濃度が一様でない場所にインク滲みがある場合の画素値分布を模式的に示す図The figure which shows typically pixel value distribution in case an ink bleed exists in the place where background density is not uniform
　以下に、添付図面を参照して、本発明に係る紙葉類判別手法の好適な実施形態を詳細に説明する。なお、以下では、本発明に係る紙葉類判別手法の概要について説明した後に、本発明に係る紙葉類判別手法を適用した紙幣判別装置についての実施形態を説明することとする。 Hereinafter, preferred embodiments of the paper sheet discrimination method according to the present invention will be described in detail with reference to the accompanying drawings. In addition, below, after demonstrating the outline | summary of the paper sheet discrimination | determination method concerning this invention, suppose that embodiment about the banknote discrimination | determination apparatus to which the paper sheet discrimination | determination method concerning this invention is applied is described.
＜本発明に係る紙葉類判別手法の概要＞
　図１は、本発明に係る紙葉類判別手法の概要を示す図である。本発明に係る紙葉類判別手法では、まず、判別対象である紙葉類に光を照射し、判別対象である紙葉類からの透過光または反射光に基づいて判別対象である紙葉類の撮像画像を生成する（図１の（１）参照）。 <Outline of Paper Sheet Discriminating Method According to the Present Invention>
FIG. 1 is a diagram showing an outline of a paper sheet discrimination method according to the present invention. In the paper sheet discriminating method according to the present invention, first, the paper sheet that is the discrimination target is irradiated with light, and the paper sheet that is the discrimination target based on the transmitted or reflected light from the paper sheet that is the discrimination target The captured image is generated (see (1) in FIG. 1).
　次に、判別対象である紙葉類の撮像画像から判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点を抽出する（図１の（２）参照）。ここで、エッジとは、画像の明暗が著しく変化している箇所のことを指す。以下の説明では、エッジの濃度が明るい方から暗い方に向かう方向を濃度勾配方向としている。また、エッジ点とは、画像中のエッジに該当する画素とする。 Next, edge points in the density gradient direction range along the longitudinal direction of the paper sheet to be discriminated are extracted from the captured image of the paper sheet to be discriminated (see (2) in FIG. 1). Here, the edge refers to a portion where the contrast of the image is remarkably changed. In the following description, the direction from the bright edge to the dark edge is the density gradient direction. An edge point is a pixel corresponding to an edge in an image.
　例えば図１の（２）に示したように、判別対象となる紙葉類の左端から右端に向かう方向に対して±１２．５度の幅を持って判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲（図１の（２）においてＡ方向範囲と表記）のエッジ点と、判別対象となる紙葉類の右端から左端に向かう方向に対して±１２．５度の幅を持って判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲（図１の（２）においてＢ方向範囲と表記）のエッジ点とを抽出する。 For example, as shown in (2) of FIG. 1, the longitudinal direction of the paper sheet to be discriminated with a width of ± 12.5 degrees with respect to the direction from the left end to the right end of the paper sheet to be discriminated. A width of ± 12.5 degrees with respect to the edge point of the density gradient direction range (indicated as the A direction range in FIG. 1B) and the direction from the right edge to the left edge of the sheet to be identified The edge point of the density gradient direction range (denoted as the B direction range in (2) of FIG. 1) along the longitudinal direction of the paper sheet to be discriminated is extracted.
　紙幣等の紙葉類では短手方向に沿ったテープの貼付が想定されるため、上記のような特定のエッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点を抽出することができる。 For paper sheets such as banknotes, it is assumed that the tape is attached along the short direction, so the edge point that may have occurred due to the side edge of the tape by extracting the specific edge point as described above Can be extracted.
　次に、抽出した特定のエッジ点から、正当な紙葉類の撮像画像に含まれる正当な紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点である参照エッジ点に対応するエッジ点および正当な紙葉類の撮像画像に含まれていない画素が明るい領域、即ち本実施形態では画素値の大きい領域に起因して発生したと推定したエッジ点を取り除いて残存エッジ点を抽出する（図１の（３）参照）。ここで、正当な紙葉類とは、汚れやしわ、折り目などの汚損が生じておらずテープの貼付もない紙葉類を意味している。 Next, from the extracted specific edge point, the edge point corresponding to the reference edge point that is the edge point of the density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the legitimate paper sheet Further, the remaining edge points are extracted by removing the edge points that are estimated to have been generated due to the bright areas where the pixels not included in the captured image of the legitimate paper sheet are bright, that is, the areas having a large pixel value in this embodiment ( (See (3) in FIG. 1). Here, a legitimate paper sheet means a paper sheet that is free from contamination such as dirt, wrinkles, and folds and is not attached with a tape.
　特定のエッジ点を抽出する際に用いた「判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲」と、参照エッジ点を求める際に用いる「正当な紙葉類の撮像画像に含まれる正当な紙葉類の長手方向に沿った濃度勾配方向範囲」とは完全一致していなくても構わないが、完全一致していることが望ましい。 “Density gradient direction range along the longitudinal direction of the paper sheet to be discriminated” used when extracting a specific edge point, and “A legitimate paper sheet image to be used when obtaining a reference edge point” The “concentration gradient direction range along the longitudinal direction of the legitimate paper sheets included” may not completely match, but it is desirable that they completely match.
　上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点から紙葉類の図柄に起因して発生したエッジ点を取り除くことができる。また、テープが貼付された領域ではテープの影響によって画素が暗くなる、即ち本実施形態では画素値が小さくなるため、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点からテープ側方端に起因して発生していないと推定したエッジ点を取り除くことができる。 By extracting the remaining edge points as described above, the edge points generated due to the design of the paper sheet can be removed from the edge points that may have been generated due to the side edge of the tape. Also, in the area where the tape is applied, the pixel becomes dark due to the influence of the tape, that is, the pixel value becomes small in this embodiment. It is possible to remove an edge point that is estimated not to have been generated due to the side edge of the tape from the edge point that may have occurred.
　最後に、抽出した残存エッジ点に基づいて判別対象である紙葉類にテープが貼られているかを解析する。 Finally, based on the extracted remaining edge point, it is analyzed whether the tape is stuck on the paper sheet to be discriminated.
　このように本発明に係る紙葉類判別手法では、テープ貼付を光学的に検知している。従って、薄いテープが貼られている場合でも紙葉類にテープが貼られているか否かを判別することができる。また、紙葉類に対して斜め上方から光を照射することで発生するテープ側方端の明るい反射や影を利用しないので、光源の位置を工夫する必要がない。さらに、本発明に係る紙葉類判別手法では、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点から紙葉類の図柄に起因して発生したエッジ点を取り除くことができる。また、テープが貼付された領域ではテープの影響によって画素値が小さくなるため、上記のような残存エッジ点の抽出により、テープ側方端に起因して発生した可能性があるエッジ点からテープ側方端に起因して発生していないと推定したエッジ点を取り除くことができる。したがって、テープ貼付の検知精度を高くすることができる。 Thus, in the paper sheet discrimination method according to the present invention, tape sticking is optically detected. Therefore, even when a thin tape is stuck, it can be determined whether or not the tape is stuck on the paper sheet. Further, since the bright reflection and shadow at the side edge of the tape generated by irradiating light on the paper sheet from obliquely above is not used, it is not necessary to devise the position of the light source. Furthermore, in the paper sheet discriminating method according to the present invention, due to the extraction of the remaining edge point as described above, the edge point that may have occurred due to the side edge of the tape is caused by the design of the paper sheet. The generated edge point can be removed. Also, since the pixel value is reduced due to the influence of the tape in the area where the tape is applied, the extraction of the remaining edge point as described above causes the tape side from the edge point that may have occurred due to the side edge of the tape. Edge points estimated not to be generated due to the edge can be removed. Therefore, the detection accuracy of tape sticking can be increased.
　以下では、図１を用いて説明した本発明に係る紙葉類判別手法を適用した紙幣判別装置についての実施形態を詳細に説明するが、本発明に係る紙葉類判別手法は紙幣のみならず、小切手、手形及び商品券等、他の任意の紙葉類に対しても適用することができる。 Hereinafter, an embodiment of the bill discriminating apparatus to which the paper sheet discriminating method according to the present invention described with reference to FIG. 1 is applied will be described in detail. However, the paper sheet discriminating method according to the present invention is not limited to bills. It can also be applied to other arbitrary paper sheets such as checks, bills and gift certificates.
＜第１実施形態＞
　図２は、本発明の第１実施形態に係る紙幣判別装置１０の構成を示すブロック図である。なお、図２においては紙幣判別装置１０の特徴を説明するために必要な構成要素のみを示しており、一般的な構成要素についての記載を省略している。 <First Embodiment>
FIG. 2 is a block diagram showing the configuration of the banknote discriminating apparatus 10 according to the first embodiment of the present invention. In FIG. 2, only constituent elements necessary for explaining the features of the banknote discriminating apparatus 10 are shown, and descriptions of general constituent elements are omitted.
　紙幣判別装置１０は、イメージラインセンサ部１と、制御部２と、記憶部３とを備えている。また、制御部２は、画像データ取得部２ａと、金種識別部２ｂと、エッジ点抽出部２ｃと、残存エッジ点抽出部２ｄと、解析部２ｅとを備えている。また、記憶部３は、金種識別テンプレート３ａと、各種フィルタ３ｂと、参照エッジ点３ｃと、解析基準情報３ｄとを記憶している。 The bill discriminating apparatus 10 includes an image line sensor unit 1, a control unit 2, and a storage unit 3. The control unit 2 includes an image data acquisition unit 2a, a denomination identification unit 2b, an edge point extraction unit 2c, a remaining edge point extraction unit 2d, and an analysis unit 2e. The storage unit 3 stores a denomination identification template 3a, various filters 3b, a reference edge point 3c, and analysis standard information 3d.
　イメージラインセンサ部１は、図示しない搬送機構によって搬送される紙幣からの透過光または反射光を受光するセンサ部であり、複数の受光センサを直線状に配置することで構成される。紙幣に照射する光としては、汚れに反応しにくい赤外波長の光が好ましいが、白色、赤色、緑色、青色などの可視光でも良い。また、イメージラインセンサ部１は、受光結果を制御部２の画像データ取得部２ｂに出力する処理を併せて行う。 The image line sensor unit 1 is a sensor unit that receives transmitted light or reflected light from banknotes conveyed by a conveyance mechanism (not shown), and is configured by arranging a plurality of light receiving sensors in a straight line. The light applied to the banknote is preferably light having an infrared wavelength that hardly reacts to dirt, but may be visible light such as white, red, green, and blue. The image line sensor unit 1 also performs a process of outputting the light reception result to the image data acquisition unit 2 b of the control unit 2.
　制御部２は、イメージラインセンサ部１からの出力に基づいて紙幣の画像データを生成し、生成した画像データを解析して紙幣にテープが貼られているかの判別を行う処理部である。 The control unit 2 is a processing unit that generates image data of banknotes based on the output from the image line sensor unit 1 and analyzes the generated image data to determine whether a tape is stuck on the banknotes.
　画像データ取得部２ａは、イメージラインセンサ部１からの出力データをメモリに展開し、１枚の紙幣ごとに合成し、紙幣全体についての画像データを生成する処理を行う処理部である。また、画像データ取得部２ａは、生成した画像データを金種識別部２ｂおよびエッジ点抽出部２ｃにそれぞれ出力する処理を併せて行う。 The image data acquisition unit 2a is a processing unit that performs processing to develop output data from the image line sensor unit 1 in a memory, synthesize it for each banknote, and generate image data for the entire banknote. The image data acquisition unit 2a also performs a process of outputting the generated image data to the denomination identifying unit 2b and the edge point extracting unit 2c.
　金種識別部２ｂは、画像データ取得部２ａによって生成された画像データの特徴パターンと、紙幣の金種ごとの特徴パターンである金種識別テンプレート３ａとを比較して、紙幣の金種を判定する。 The denomination identifying unit 2b compares the feature pattern of the image data generated by the image data acquiring unit 2a with the denomination identifying template 3a that is a feature pattern for each denomination of the bill, and determines the denomination of the bill. To do.
　エッジ点抽出部２ｃは、各種フィルタ３ｂを用いて、画像データ取得部２ｂが出力した画像データを平滑化し、平滑化した画像データから紙幣の長手方向に沿った濃度勾配方向範囲のエッジ点を抽出する処理を行う処理部である。また、エッジ点抽出部２ｃは、抽出したエッジ点を示すエッジ点画像を残存エッジ点抽出部２ｄに出力する処理を併せて行う。 The edge point extraction unit 2c uses various filters 3b to smooth the image data output by the image data acquisition unit 2b, and extracts edge points in the density gradient direction range along the longitudinal direction of the banknote from the smoothed image data. It is a processing part which performs the process to perform. The edge point extraction unit 2c also performs a process of outputting an edge point image indicating the extracted edge point to the remaining edge point extraction unit 2d.
　本実施形態では、エッジ点抽出部２ｃは、紙幣の左端から右端に向かう方向に対して±１２．５度の幅を持って紙幣の長手方向に沿った濃度勾配方向範囲（以下、Ａ方向範囲ともいう）のエッジ点と、紙幣の右端から左端に向かう方向に対して±１２．５度の幅を持って紙幣の長手方向に沿った濃度勾配方向範囲（以下、Ｂ方向範囲ともいう）のエッジ点とを抽出する。ここで±１２．５度の幅を持っているのは、テープが斜めに貼られていることを考慮しているためである。しかしながら、＋１２．５度は一例であって０度以上＋４５度以下の任意の値であれば良い。同様に、－１２．５度も一例であって－４５度以上０度以下の任意の値であれば良い。また、各濃度勾配方向範囲は紙幣の長手方向に対して線対称で無くても良く、両濃度勾配方向範囲は紙幣の短手方向に対して線対称で無くても良い。また、右側テープ側方端および左側テープ側方端のいずれか一方が確実に検知できなくなるが、前者のエッジ点および後者のエッジ点のいずれか一方のみを抽出する形態であっても構わない。 In the present embodiment, the edge point extraction unit 2c has a concentration gradient direction range (hereinafter referred to as an A direction range) having a width of ± 12.5 degrees with respect to the direction from the left end to the right end of the banknote along the longitudinal direction of the banknote. Edge point) and a concentration gradient direction range (hereinafter also referred to as a B direction range) along the longitudinal direction of the bill with a width of ± 12.5 degrees with respect to the direction from the right end to the left end of the bill. Extract edge points. The reason why the width is ± 12.5 degrees is that the tape is applied obliquely. However, +12.5 degrees is an example and may be any value between 0 degrees and +45 degrees. Similarly, −12.5 degrees is an example, and any value between −45 degrees and 0 degrees may be used. Further, each concentration gradient direction range may not be line symmetric with respect to the longitudinal direction of the banknote, and both concentration gradient direction ranges may not be line symmetrical with respect to the short direction of the banknote. In addition, either the right tape side end or the left tape side end cannot be reliably detected, but only one of the former edge point and the latter edge point may be extracted.
　画像データのフィルタ処理では、フィルタの中心と注目画素とが重なるようにし、各重なり位置においてフィルタの係数と画素の画素値とを乗算し、それぞれの乗算値の和を注目画素の画素値とする。 In the filter processing of image data, the center of the filter and the target pixel are overlapped, the filter coefficient is multiplied by the pixel value of the pixel at each overlap position, and the sum of the respective multiplication values is used as the pixel value of the target pixel. .
　平滑化においては、例えば図３に示す３×３画素の係数が全て１である平滑化フィルタを用いることができる。平滑化によって、画像に重畳しているランダムなノイズを除去することができる。なお、平滑化を行わない場合でも、エッジ点および濃度勾配方向の検出を行うことは可能である。 In smoothing, for example, a smoothing filter in which all the coefficients of 3 × 3 pixels shown in FIG. 3 are 1 can be used. By smoothing, random noise superimposed on the image can be removed. Even when smoothing is not performed, it is possible to detect edge points and density gradient directions.
　また、エッジ点の検出においては、例えば図４に示す３×３画素の８方向ラプラシアンフィルタを用いることができる。ラプラシアンフィルタを用いたフィルタ処理によって検出されるゼロクロス点が原画像のエッジ部分となる。 In the detection of edge points, for example, a 3 × 3 pixel 8-direction Laplacian filter shown in FIG. 4 can be used. A zero-cross point detected by filter processing using a Laplacian filter is an edge portion of the original image.
　また、濃度勾配方向の検出においては、例えば図５に示す３×３画素の横方向Prewittフィルタおよび図６に示す３×３画素の縦方向Prewittフィルタを用いることができる。横方向Prewittフィルタを用いたフィルタ処理によって得られる注目画素の画素値と縦方向Prewittフィルタを用いたフィルタ処理によって得られる注目画素の画素値との間の、正負組合せおよび絶対値の比によって濃度勾配方向を検出することができる。 Further, in the detection of the density gradient direction, for example, a 3 × 3 pixel horizontal Prewitt filter shown in FIG. 5 and a 3 × 3 pixel vertical Prewitt filter shown in FIG. 6 can be used. Density gradient by the ratio of positive and negative combination and absolute value between pixel value of target pixel obtained by filter processing using horizontal Prewitt filter and pixel value of target pixel obtained by filter processing using vertical Prewitt filter The direction can be detected.
　なお、上記の説明では、８方ラプラシアンフィルタ、横方向Prewittフィルタおよび縦方向Prewittフィルタを用いてエッジ点と濃度勾配方向を検出する例を示したが、Sobelフィルタなど他のフィルタを用いることとしてもよいし、各種フィルタを適宜組み合わせることとしても良い。また、各種フィルタのサイズや係数についても特に限定されない。 In the above description, an example in which an edge point and a density gradient direction are detected using an 8-way Laplacian filter, a horizontal direction Prewitt filter, and a vertical direction Prewitt filter has been described. However, other filters such as a Sobel filter may be used. Alternatively, various filters may be appropriately combined. Also, the size and coefficient of various filters are not particularly limited.
　図２の説明に戻り、残存エッジ点抽出部２ｄについて説明する。 Referring back to FIG. 2, the remaining edge point extraction unit 2d will be described.
　残存エッジ点抽出部２ｄは、エッジ点抽出部２ｃによって抽出されたエッジ点から、金種識別部２ｂによって識別された金種の参照エッジ点に対応するエッジ点および正当な紙幣の撮像画像に含まれていない画素値の大きい領域に起因して発生したと推定したエッジ点を取り除く。 The remaining edge point extracting unit 2d is included in the edge point corresponding to the denomination reference edge point identified by the denomination identifying unit 2b from the edge point extracted by the edge point extracting unit 2c and the captured image of the valid banknote. An edge point estimated to be generated due to a region having a large pixel value that is not present is removed.
　また、残存エッジ点抽出部２ｄは、判別対称となる紙幣の画像データに、正当な紙幣の撮像画像に含まれていない判別対象となる紙幣の短手方向に沿った画素値の大きい細線状領域が存在していると推定した場合に、その細線状領域の周囲に位置するエッジ点もエッジ点抽出部２ｃによって抽出されたエッジ点から取り除く。なお、上記の３種類のエッジ点を取り除く順番は特に限定されない。また、１種類ずつ順に取り除いても良く、複数種類のエッジ点を同時に取り除いても良い。 In addition, the remaining edge point extraction unit 2d has a thin line area with a large pixel value along the short direction of the banknote to be discriminated that is not included in the captured image of the legitimate banknote in the image data of the banknote that is discriminatively symmetric. Is estimated, the edge points located around the thin line area are also removed from the edge points extracted by the edge point extraction unit 2c. The order of removing the above three types of edge points is not particularly limited. Further, one type may be removed in order, or a plurality of types of edge points may be removed at the same time.
　本実施形態では、残存エッジ点抽出部２ｄは、エッジ点抽出部２ｃによって抽出されたＡ方向範囲のエッジ点を示すエッジ点画像、後述するＡ方向範囲の参照エッジ点を示す画像、および後述する各推定処理の結果を用いて、Ａ方向範囲の残存エッジ点を示すエッジ点画像を生成する。同様に、残存エッジ点抽出部２ｄは、エッジ点抽出部２ｃによって抽出されたＢ方向範囲のエッジ点を示すエッジ点画像、後述するＢ方向範囲の参照エッジ点を示す画像、および後述する各推定処理の結果を用いて、Ｂ方向範囲の残存エッジ点を示すエッジ点画像を生成する。また、残存エッジ点抽出部２ｄは、Ａ方向範囲の残存エッジ点を示すエッジ点画像およびＢ方向範囲の残存エッジ点を示すエッジ点画像を解析部２ｅに出力する処理を併せて行う。 In the present embodiment, the remaining edge point extracting unit 2d is an edge point image indicating edge points in the A direction range extracted by the edge point extracting unit 2c, an image indicating reference edge points in the A direction range described later, and described later. Using the result of each estimation process, an edge point image indicating the remaining edge points in the A direction range is generated. Similarly, the remaining edge point extraction unit 2d includes an edge point image indicating edge points in the B direction range extracted by the edge point extraction unit 2c, an image indicating reference edge points in the B direction range described later, and estimations described later. An edge point image indicating the remaining edge points in the B direction range is generated using the processing result. The remaining edge point extracting unit 2d also performs processing of outputting an edge point image indicating the remaining edge points in the A direction range and an edge point image indicating the remaining edge points in the B direction range to the analyzing unit 2e.
　ここで、参照エッジ点の作成手順の一例について説明する。参照エッジ点とは正当な紙幣の画像データに現れるエッジ点であり、テープのエッジ点を抽出するため、除去すべきエッジ点のマスクパターンとして使用する。 Here, an example of a procedure for creating a reference edge point will be described. The reference edge point is an edge point appearing in legitimate banknote image data, and is used as a mask pattern of the edge point to be removed in order to extract the edge point of the tape.
　まず、複数枚（例えば２００枚）の正当な紙幣の画像データについて、Ａ方向範囲のエッジ点を検出し、判定閾値（例えば５枚）以上の枚数で同一位置のエッジ点があれば、Ａ方向範囲の有効エッジ点とする。そして、判別対象となる紙幣と正当な紙幣の位置ずれの吸収を主たる目的として、有効エッジ点を周辺画素に拡張する膨張処理を行う。周辺画素としては、例えば隣接する近傍８画素としても良く、紙幣の左端から右端に向かう方向に隣接する近傍１画素としても良い。このようにして得られたＡ方向範囲の有効エッジ点をＡ方向範囲の参照エッジ点とする。記憶部３はＡ方向範囲の参照エッジ点を示す画像の形式でＡ方向範囲の参照エッジ点を記憶する。 First, with respect to a plurality of (for example, 200) valid banknote image data, edge points in the A direction range are detected. The effective edge point of the range. And the expansion process which expands an effective edge point to a surrounding pixel is mainly performed for the purpose of absorption of the position shift of the banknote used as a discrimination | determination object, and a valid banknote. The neighboring pixels may be, for example, adjacent eight neighboring pixels, or may be one neighboring pixel adjacent in the direction from the left end to the right end of the bill. The effective edge point in the A direction range obtained in this way is set as the reference edge point in the A direction range. The storage unit 3 stores the reference edge point in the A direction range in the form of an image showing the reference edge point in the A direction range.
　同様に、複数枚（例えば２００枚）の正当な紙幣の画像データについて、Ｂ方向範囲のエッジ点を検出し、判定閾値（例えば５枚）以上の枚数で同一位置のエッジ点があれば、Ｂ方向範囲の有効エッジ点とする。そして、判別対象となる紙幣と正当な紙幣の位置ずれの吸収を主たる目的として、有効エッジ点を周辺画素に拡張する膨張処理を行う。周辺画素としては、例えば隣接する近傍８画素としても良く、紙幣の左端から右端に向かう方向に隣接する近傍１画素としても良い。このようにして得られたＢ方向範囲の有効エッジ点をＢ方向範囲の参照エッジ点とする。記憶部３はＢ方向範囲の参照エッジ点を示す画像の形式でＢ方向範囲の参照エッジ点を記憶する。 Similarly, with respect to a plurality of (for example, 200) valid banknote image data, an edge point in the B direction range is detected, and if there is an edge point at the same position with the number of determination thresholds (for example, 5) or more, B The effective edge point of the direction range. And the expansion process which expands an effective edge point to a surrounding pixel is mainly performed for the purpose of absorption of the position shift of the banknote used as a discrimination | determination object, and a valid banknote. The neighboring pixels may be, for example, adjacent eight neighboring pixels, or may be one neighboring pixel adjacent in the direction from the left end to the right end of the bill. The effective edge point in the B direction range obtained in this way is set as the reference edge point in the B direction range. The storage unit 3 stores the reference edge point in the B direction range in the form of an image indicating the reference edge point in the B direction range.
　上記で説明したＡ方向範囲の参照エッジ点およびＢ方向範囲の参照エッジ点は金種によって異なるので、金種ごとに記憶されている。また、上記で説明した参照エッジ点の作成は紙幣判別装置１０の製品出荷前に行われ、参照エッジ点３ｃがあらかじめ記憶部３に記憶された状態で紙幣判別装置１０が製品出荷される。参照エッジ点の作成は紙幣判別装置１０以外の装置を用いて実施しても良く、紙幣判別装置１０自体を用いて実施しても良い。また、記憶部３の記憶内容の書き換えを可能にするためのインターフェースを紙幣判別装置１０に設け、参照エッジ点３ｃの追加や修正などが容易に行えるようにしても良い。 Since the reference edge point in the A direction range and the reference edge point in the B direction range described above differ depending on the denomination, they are stored for each denomination. In addition, the reference edge point described above is created before the product shipment of the banknote discriminating apparatus 10, and the banknote discrimination apparatus 10 is shipped in a state where the reference edge point 3c is stored in the storage unit 3 in advance. The creation of the reference edge point may be performed using an apparatus other than the banknote discriminating apparatus 10 or may be performed using the banknote discriminating apparatus 10 itself. Further, an interface for enabling rewriting of the contents stored in the storage unit 3 may be provided in the bill discriminating apparatus 10 so that the reference edge point 3c can be easily added or corrected.
　ここで、注目エッジ点が正当な紙幣の撮像画像に含まれていない例えばしわ、折れのような画素値の大きい領域に起因して発生したエッジ点であるか否かを推定する第１の推定処理について図７のフローチャートを用いて説明する。かかる第１の推定処理は残存エッジ点抽出部２ｄが実行する。かかる第１の推定処理によって処理される注目エッジ点はエッジ点抽出部２ｃによって抽出されたエッジ点が最大となる。例えば、かかる第１の推定処理の実行前に、エッジ点抽出部２ｃによって抽出されたエッジ点から金種識別部２ｂによって識別された金種の参照エッジ点に対応するエッジ点が取り除かれている場合には、残っているエッジ点がかかる第１の推定処理によって処理される注目エッジ点となる。 Here, the first estimation for estimating whether or not the target edge point is an edge point generated due to a region having a large pixel value such as a wrinkle or a fold that is not included in the captured image of a valid banknote. Processing will be described with reference to the flowchart of FIG. The first estimation process is executed by the remaining edge point extraction unit 2d. The edge point extracted by the edge point extraction unit 2c is the maximum as the target edge point processed by the first estimation process. For example, before execution of the first estimation process, the edge points corresponding to the denomination reference edge points identified by the denomination identifying unit 2b are removed from the edge points extracted by the edge point extracting unit 2c. In this case, the remaining edge point becomes the target edge point processed by the first estimation process.
　残存エッジ点抽出部２ｄは、判別対象となる紙幣の撮像画像の最頻出画素値を求める（ステップＳ１）。図８は、判別対象となる紙幣の撮像画像に関する画素値ヒストグラムの一例を示す図である。図８に示す例では、判別対象となる紙幣の撮像画像の濃淡が２５６諧調であり、画素値０の画素が最も暗い画素であり、画素値２５６の画素が最も明るい画素であり、画素値１８８が最頻出画素値となっている。本実施形態では、上記の“最頻出画素値”を、判別対象となる紙幣の撮像画像の背景を代表する画素値として、ステップＳ２以降において利用する。ステップＳ２以降の処理は個々の注目エッジ点に対して実行される。 The remaining edge point extraction unit 2d obtains the most frequently appearing pixel value of the captured image of the banknote to be determined (step S1). FIG. 8 is a diagram illustrating an example of a pixel value histogram relating to a captured image of a bill to be determined. In the example shown in FIG. 8, the density of the captured image of the banknote to be determined is 256 gradations, the pixel with a pixel value of 0 is the darkest pixel, the pixel with a pixel value of 256 is the brightest pixel, and the pixel value is 188. Is the most frequent pixel value. In the present embodiment, the “most frequently occurring pixel value” is used as a pixel value representing the background of the captured image of the banknote to be determined in step S2 and subsequent steps. The processing after step S2 is executed for each target edge point.
　次に、残存エッジ点抽出部２ｄは、注目エッジ点の左側（紙幣の左端側）に隣接して紙幣の右端から左端に向かう方向で連続して並ぶ３つの画素の画素値それぞれが上記の“最頻出画素値”から５を引いた値より小さい、又は、注目エッジ点の右側（紙幣の右端側）に隣接して紙幣の左端から右端に向かう方向で連続して並ぶ３つの画素の画素値それぞれが上記の“最頻出画素値”から５を引いた値より小さいという第１の条件を満たすか否かを判定する（ステップＳ２）。 Next, the remaining edge point extraction unit 2d has the pixel values of the three pixels lined up successively in the direction from the right end to the left end of the banknote adjacent to the left side (the left end side of the banknote) of the target edge point. The pixel value of three pixels that are smaller than the value obtained by subtracting 5 from the “most frequently appearing pixel value”, or that are adjacent to the right side of the target edge point (the right end side of the banknote) and that are successively arranged in the direction from the left end to the right end of the banknote. It is determined whether or not the first condition that each is smaller than a value obtained by subtracting 5 from the “most frequently used pixel value” (step S2).
　テープが貼付された領域ではテープの影響によって画素値が小さくなる。このため、上記第１の条件を満たす場合には、注目エッジ点がテープ側方端に起因して発生したと推定することができる。したがって、上記第１の条件を満たすと判定した場合（ステップＳ２のＹＥＳ）、残存エッジ点抽出部２ｄは、注目エッジ点が正当な紙幣の撮像画像に含まれていない画素値の大きい領域に起因して発生したエッジ点でないと推定する（ステップＳ３）。 In the area where the tape is affixed, the pixel value becomes smaller due to the influence of the tape. For this reason, when the first condition is satisfied, it can be estimated that the target edge point is generated due to the side edge of the tape. Therefore, when it is determined that the first condition is satisfied (YES in step S2), the remaining edge point extracting unit 2d is caused by a region having a large pixel value in which the target edge point is not included in the captured image of the valid banknote. It is estimated that the edge point is not generated (step S3).
　一方、上記第１の条件を満たさない場合には、注目エッジ点がテープ側方端に起因して発生していない可能性がある。そこで、上記第１の条件を満たすと判定しなかった場合（ステップＳ２のＮＯ）、残存エッジ点抽出部２ｄは、注目エッジ点の左側（紙幣の左端側）に隣接して紙幣の右端から左端に向かう方向で連続して並ぶ３つの画素の画素値それぞれと、注目エッジ点の右側（紙幣の右端側）に隣接して紙幣の左端から右端に向かう方向で連続して並ぶ３つの画素の画素値それぞれの片方が上記の“最頻出画素値”より小さく、もう片方が上記の“最頻出画素値”に５を加えた値より小さいという第２の条件を満たすか否かを判定する（ステップＳ４）。 On the other hand, when the first condition is not satisfied, there is a possibility that the target edge point is not generated due to the side edge of the tape. Therefore, when it is not determined that the first condition is satisfied (NO in step S2), the remaining edge point extraction unit 2d is adjacent to the left side of the target edge point (the left end side of the banknote) from the right end to the left end of the banknote. Each of the pixel values of the three pixels lined up continuously in the direction toward the right side, and the pixels of the three pixels lined up sequentially in the direction from the left edge to the right edge of the banknote adjacent to the right side (right edge side of the banknote) of the target edge point It is determined whether or not the second condition is satisfied, in which one of the values is smaller than the “most frequently occurring pixel value” and the other is smaller than a value obtained by adding 5 to the “most frequently occurring pixel value”. S4).
　テープが貼付された領域ではテープの影響によって画素値が小さくなる。このため、上記第２条件を満たす場合には、注目エッジ点の周辺が比較的明るい背景であり、且つ、注目エッジ点がテープ側方端に起因して発生したと推定することができる。したがって、上記第２の条件を満たすと判定した場合（ステップＳ４のＹＥＳ）、残存エッジ点抽出部２ｄは、注目エッジ点が正当な紙幣の撮像画像に含まれていない画素値の大きい領域に起因して発生したエッジ点でないと推定する（ステップＳ３）。 In the area where the tape is affixed, the pixel value becomes smaller due to the influence of the tape. Therefore, when the second condition is satisfied, it can be estimated that the periphery of the target edge point is a relatively bright background and the target edge point is generated due to the side edge of the tape. Therefore, when it is determined that the second condition is satisfied (YES in step S4), the remaining edge point extraction unit 2d is caused by a region having a large pixel value in which the target edge point is not included in the captured image of the valid banknote. It is estimated that the edge point is not generated (step S3).
　一方、上記第１の条件も上記第２の条件も満たさない場合には、注目エッジ点がテープ側方端に起因して発生したと考え難い。したがって、上記第２の条件を満たすと判定しなかった場合（ステップＳ４のＮＯ）、残存エッジ点抽出部２ｄは、注目エッジ点が正当な紙幣の撮像画像に含まれていない画素値の大きい領域に起因して発生したエッジ点であると推定する（ステップＳ５）。 On the other hand, when neither the first condition nor the second condition is satisfied, it is unlikely that the target edge point has occurred due to the side edge of the tape. Therefore, when it is not determined that the second condition is satisfied (NO in step S4), the remaining edge point extraction unit 2d has a large pixel value where the target edge point is not included in the captured image of the valid banknote. It is estimated that the edge point is generated due to (step S5).
　なお、上記のステップＳ２およびステップＳ４で用いた各判定条件はあくまで一例であり、判定条件において用いた閾値などは特に限定されない。 Note that the determination conditions used in steps S2 and S4 are merely examples, and the threshold values used in the determination conditions are not particularly limited.
　ここで、正当な紙幣の撮像画像に含まれていない判別対象となる紙幣の短手方向に沿った画素値の大きい細線状領域が判別対象となる紙幣の撮像画像に存在しているか否かを推定する第２の推定処理について図９のフローチャートを用いて説明する。かかる第２の推定処理は残存エッジ点抽出部２ｄが実行する。 Here, it is determined whether or not a thin line area having a large pixel value along the short direction of the banknote to be determined that is not included in the captured image of the valid banknote exists in the captured image of the banknote to be determined. The second estimation process to be estimated will be described using the flowchart of FIG. The second estimation process is executed by the remaining edge point extraction unit 2d.
　残存エッジ点抽出部２ｄは、判別対象となる紙幣の撮像画像の最頻出画素値を求める（ステップＳ１１）。ステップＳ１１の処理は、上述した図７のフローチャートにおけるステップＳ１の処理と同一である。 The remaining edge point extraction unit 2d obtains the most frequently appearing pixel value of the captured image of the banknote to be discriminated (step S11). The process of step S11 is the same as the process of step S1 in the flowchart of FIG.
　次に、残存エッジ点抽出部２ｄは、判別対象となる紙幣の撮像画像を対象として縦方向（紙幣の短手方向）の画素値の平均値を横方向（紙幣の長手方向）の各画素位置で算出する（ステップＳ１２）。ステップＳ１２の処理で得られた算出結果の一例をグラフで表すと、図１０のようになる。 Next, the remaining edge point extraction unit 2d determines the average value of the pixel values in the vertical direction (short direction of the banknote) for each captured pixel image in the horizontal direction (longitudinal direction of the banknote). (Step S12). An example of the calculation result obtained by the process of step S12 is represented as a graph in FIG.
　次に、残存エッジ点抽出部２ｄは、横方向の幅３画素分を判定対象として、条件(I)、条件(II)、条件(III)を全て満たすか否かを判定する（ステップＳ１３）。条件(I)は、判定対象である横方向の幅３画素分において、３つある縦方向の画素値の平均値の少なくとも一つが最頻出画素値より大きいという条件である。条件(II)は、判定対象である横方向の幅３画素分の左端である縦方向の画素値の平均値がその左隣の縦方向の画素値の平均値より５以上大きいという条件である。条件(III)は、判定対象である横方向の幅３画素分の右端である縦方向の画素値の平均値がその右隣の縦方向の画素値の平均値より５以上大きいという条件である。 Next, the remaining edge point extraction unit 2d determines whether or not all of the conditions (I), (II), and (III) are satisfied, with the horizontal width of three pixels as a determination target (step S13). . Condition (I) is a condition in which at least one of the average values of the three vertical pixel values is larger than the most frequent pixel value in the three horizontal width pixels to be determined. Condition (II) is a condition that the average value of the vertical pixel values at the left end of the three horizontal pixels to be determined is 5 or more larger than the average value of the vertical pixel values adjacent to the left side. . Condition (III) is a condition that the average value of the vertical pixel values at the right end of the three horizontal pixels to be determined is 5 or more larger than the average value of the vertical pixel values adjacent to the right. .
　条件(I)、条件(II)、条件(III)を全て満足している場合（ステップＳ１３のＹＥＳ）、残存エッジ点抽出部２ｄは、ステップＳ１３の判定対象である横方向の幅３画素分が明るい縦細線であると推定する（ステップＳ１４）。なお、明るい縦細線とは、正当な紙幣の撮像画像に含まれていない判別対象となる紙幣の短手方向に沿った画素値の大きい細線状領域を意味している。この明るい縦細線は強い折り目により発生する。 When all of the conditions (I), (II), and (III) are satisfied (YES in step S13), the remaining edge point extraction unit 2d has a width of 3 pixels that is the determination target in step S13. Is a bright vertical thin line (step S14). Note that the bright vertical thin line means a thin linear region having a large pixel value along the short direction of the banknote to be determined that is not included in the captured image of the legitimate banknote. This bright vertical line is generated by a strong crease.
　一方、条件(I)、条件(II)、条件(III)の少なくとも一つを満足していない場合（ステップＳ１３のＮＯ）、残存エッジ点抽出部２ｄは、ステップＳ１３の判定対象である横方向の幅３画素分が明るい縦細線でないと推定する（ステップＳ１５）。 On the other hand, when at least one of the condition (I), the condition (II), and the condition (III) is not satisfied (NO in step S13), the remaining edge point extraction unit 2d is the horizontal direction that is the determination target in step S13. It is estimated that the width of 3 pixels is not a bright vertical thin line (step S15).
　その後、ステップＳ１３の判定対象である横方向の幅３画素分を１画素ずつ横方向にスライドさせながら、上述したステップＳ１３以降の処理を繰り返す。 Thereafter, the above-described processing from step S13 onward is repeated while sliding the horizontal width of 3 pixels, which is the determination target in step S13, in the horizontal direction one pixel at a time.
　そして、本実施形態では、明るい縦細線とその両隣１画素分、すなわち明るい縦細線を中央とする横方向の幅５画素分に含まれるエッジ点を、エッジ点抽出部２ｃによって抽出されたエッジ点から取り除いている。これにより、正当な紙幣の撮像画像に含まれていない判別対象となる紙幣の短手方向に沿った画素値の大きい細線状領域によって現れたエッジ点をテープ側方端によるエッジ点であると誤検知することを防止することができる。 In this embodiment, the edge points included in the bright vertical thin line and one pixel on both sides thereof, that is, the horizontal width of five pixels centered on the bright vertical thin line, are extracted by the edge point extracting unit 2c. Removed from. As a result, an edge point appearing by a thin line-shaped region having a large pixel value along the short direction of the banknote to be discriminated that is not included in the captured image of the valid banknote is erroneously determined as an edge point by the side edge of the tape. It is possible to prevent detection.
　なお、上記のステップＳ１３で用いた各判定条件はあくまで一例であり、判定条件において用いた閾値などは特に限定されない。 Note that each determination condition used in step S13 is merely an example, and the threshold value used in the determination condition is not particularly limited.
　また、上述した第２の推定処理は、テープ貼付の検知とは無関係に単独で実施することも可能である。上述した第２の推定処理を単独で実施した場合には、強い折れ線（強い折れ癖）を検知する機能となる。 Also, the above-described second estimation process can be performed independently regardless of the detection of tape sticking. When the above-described second estimation process is performed alone, it has a function of detecting a strong broken line (strong broken line).
　図２の説明に戻り、解析部２ｅについて説明する。 Returning to the description of FIG. 2, the analysis unit 2e will be described.
　解析部２ｅは、残存エッジ点抽出部２ｄから送られてくるＡ方向範囲の残存エッジ点を示すエッジ点画像およびＢ方向範囲の残存エッジ点を示すエッジ点画像を合成し、その合成画像に対して密度検出用フィルタを適用して所定サイズ領域における残存エッジ点の密度を画素値として検出する。解析部２ｅは、画素値として検出される所定サイズ領域における残存エッジ点の密度が解析基準情報３ｄとして記憶部３に記憶されている閾値を超えている場合に、テープ側方端を検知する。本実施形態では、右側テープ側方端と左側テープ側方端の両方を検知している。このため、右側テープ側方端と左側テープ側方端のいずれか一方が紙幣のスレッド部と重なる位置にあっても他方のテープ側方端を検知することができ、テープ貼付を検知することができる。 The analysis unit 2e synthesizes the edge point image indicating the remaining edge point in the A direction range and the edge point image indicating the remaining edge point in the B direction range sent from the remaining edge point extracting unit 2d, and the synthesized image Then, a density detection filter is applied to detect the density of remaining edge points in a predetermined size region as a pixel value. The analysis unit 2e detects the side edge of the tape when the density of remaining edge points in a predetermined size area detected as a pixel value exceeds a threshold value stored in the storage unit 3 as analysis reference information 3d. In this embodiment, both the right tape side edge and the left tape side edge are detected. For this reason, even if one of the right tape side edge and the left tape side edge is in a position where it overlaps with the thread portion of the banknote, the other tape side edge can be detected, and tape sticking can be detected. it can.
　例えば所定サイズ領域を縦長形状にする場合には例えば図１１に示す密度検出用フィルタを用いることができ、所定サイズ領域を斜めに傾いた形状にする場合には例えば図１２に示す密度検出用フィルタを用いることができる。所定サイズ領域を縦長形状にすることで縦（紙葉類の短手方向）に貼付されたテープを検知することができ、所定サイズ領域を斜めに傾いた形状にすることで斜めに傾いて貼付されたテープを検知することができる。 For example, when the predetermined size region is formed in a vertically long shape, for example, the density detection filter shown in FIG. 11 can be used, and when the predetermined size region is formed in an inclined shape, for example, the density detection filter shown in FIG. Can be used. By making the predetermined size area vertically long, it is possible to detect tapes that are stuck vertically (short direction of the paper), and by making the predetermined size area inclined diagonally, the tape is attached obliquely. The detected tape can be detected.
　なお、本実施形態とは異なり、Ａ方向範囲の残存エッジ点を示すエッジ点画像とＢ方向範囲の残存エッジ点を示すエッジ点画像とを合成せずにそれぞれ独立してテープ側方端を検知するようにしても良い。この場合、右側テープ側方端の検知と左側テープ側方端の検知を分離して行うことができる。例えば、右側テープ側方端と左側テープ側方端のいずれか一方が紙幣のスレッド部と重なる位置にあっても他方のテープ側方端を検知することができ、さらに他方のテープ側方端が右側テープ側方端と左側テープ側方端のどちらであるかを把握することができるので、テープ貼付を検知することができ、更にテープ貼付位置を推定することができる。 Unlike the present embodiment, the side edge of the tape is detected independently without combining the edge point image indicating the remaining edge point in the A direction range and the edge point image indicating the remaining edge point in the B direction range. You may make it do. In this case, detection of the right side edge of the right tape and detection of the left side edge of the left tape can be performed separately. For example, even if one of the right side tape side end and the left side tape side end overlaps the bill thread portion, the other tape side end can be detected, and the other tape side end Since it can be grasped whether it is a right tape side edge or a left tape side edge, a tape sticking can be detected and a tape sticking position can be estimated.
＜第２実施形態＞
　上述した本発明の第１実施形態に係る紙幣判別装置１０は、エッジ点を抽出して紙幣にテープが貼られているか否かを判別している。しかしながら、貼付されたテープの側方端によって発生するエッジが鮮明でない場合も想定される。このため、エッジ点を抽出しなくても紙幣にテープが貼られていることを検知できることが望ましい。 Second Embodiment
The banknote discriminating apparatus 10 according to the first embodiment of the present invention described above extracts an edge point and discriminates whether or not a tape is stuck on the banknote. However, it is also assumed that the edge generated by the side edge of the affixed tape is not clear. For this reason, it is desirable to be able to detect that the tape is stuck on the banknote without extracting the edge point.
　したがって、本発明の第２実施形態に係る紙幣判別装置２０は、エッジ点を抽出しなくても紙幣にテープが貼られていることを検知できる機能を本発明の第１実施形態に係る紙幣判別装置１０に追加した構成としている。 Therefore, the bill discriminating apparatus 20 according to the second embodiment of the present invention has a function capable of detecting that the tape is stuck on the bill without extracting the edge point, according to the first embodiment of the present invention. The configuration is added to the apparatus 10.
　図１３は、紙幣判別装置２０の構成を示すブロック図である。なお、図１３において図２と同一の部分には同一の符号を付し詳細な説明を省略している。 FIG. 13 is a block diagram showing a configuration of the bill discriminating apparatus 20. In FIG. 13, the same parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.
　紙幣判別装置２０の制御部２は、画像データ取得部２ａ、金種識別部２ｂ、エッジ点抽出部２ｃ、残存エッジ点抽出部２ｄ、および解析部２ｅの他に境部検知部２ｆおよび判定部２ｇを備えている。また、記憶部３は、金種識別テンプレート３ａ、各種フィルタ３ｂ、参照エッジ点３ｃ、および解析基準情報３ｄの他に検知基準情報３ｅおよび判定基準情報３ｆを記憶している。 The control unit 2 of the bill discriminating apparatus 20 includes a boundary detection unit 2f and a determination unit in addition to the image data acquisition unit 2a, denomination identification unit 2b, edge point extraction unit 2c, remaining edge point extraction unit 2d, and analysis unit 2e. 2g. The storage unit 3 stores detection standard information 3e and determination standard information 3f in addition to the denomination identification template 3a, various filters 3b, reference edge points 3c, and analysis standard information 3d.
　境部検知部２ｆは、画像データ取得部２ａによって生成された画像データを用いて、判別対象となる紙幣の長手方向の一端から他端に向かう方向で、第１領域から第１領域よりも暗い第２領域に変化する境である第１境部および第３領域から第３領域よりも明るい第４領域に変化する境である第２境部を検知する。 The boundary detection unit 2f uses the image data generated by the image data acquisition unit 2a and is darker than the first region from the first region in the direction from one end to the other end in the longitudinal direction of the bill to be determined. A first boundary portion that is a boundary that changes to the second region and a second boundary portion that is a boundary that changes from the third region to the fourth region that is brighter than the third region are detected.
　以下の説明では、判別対象となる紙幣の長手方向の一端を紙幣の左端とし、判別対象となる紙幣の長手方向の他端を紙幣の右端とするが、左端と右端を入れ替えても同様の効果を得ることができる。 In the following description, one end in the longitudinal direction of the banknote to be discriminated is set as the left end of the banknote, and the other end in the longitudinal direction of the banknote to be discriminated is set as the right end of the banknote. Can be obtained.
　境部検知部２ｆが実行する境部検知処理について図１４のフローチャートを用いて説明する。 The boundary detection process executed by the boundary detection unit 2f will be described with reference to the flowchart of FIG.
　まず境部検知部２ｆは、判別対象となる紙幣の撮像画像において横方向の高さ２画素分の着目点４を設定し、着目点４の左側に隣接する４×２画素の左側領域５を設定し、着目点の右側に隣接する４×２画素の右側領域６を設定する（ステップＳ２１）。したがって、着目点４、左側領域５、および右側領域６の位置関係は図１５に示すようになる。 First, the boundary detection unit 2f sets a point of interest 4 corresponding to a height of 2 pixels in the horizontal direction in the captured image of the banknote to be discriminated, and sets a left side region 5 of 4 × 2 pixels adjacent to the left side of the point of interest 4. The right region 6 of 4 × 2 pixels adjacent to the right side of the point of interest is set (step S21). Therefore, the positional relationship among the point of interest 4, the left region 5, and the right region 6 is as shown in FIG.
　着目点４、左側領域５、および右側領域６それぞれの構成画素数は特に限定されないが、着目点４、左側領域５、および右側領域６それぞれに紙幣の図柄によって生じるエッジ点が入らないようにする必要がある。 The number of constituent pixels of each of the point of interest 4, the left region 5, and the right region 6 is not particularly limited. However, the edge point generated by the bill design is prevented from entering each of the point of interest 4, the left region 5, and the right region 6. There is a need.
　本実施形態では、上端の近傍に図柄が存在しない紙幣を判別対象とし、図柄が存在しない上端の近傍を着目点４が横方向にスライドするように着目点４を設定する。なお、金種識別テンプレート３ａなどを利用して紙幣の横方向に応じて着目点４の縦方向位置を変更させて、着目点４、左側領域５、および右側領域６が紙幣の図柄にかからないようにしても良い。 In this embodiment, a banknote having no symbol in the vicinity of the upper end is set as a determination target, and the target point 4 is set so that the target point 4 slides in the horizontal direction in the vicinity of the upper end without the symbol. Note that the vertical position of the point of interest 4 is changed according to the horizontal direction of the banknote using the denomination identification template 3a or the like so that the point of interest 4, the left region 5 and the right region 6 do not cover the design of the banknote. Anyway.
　次に境部検知部２ｆは、着目点４が「第１領域から第１領域よりも暗い第２領域に変化する境である第１境部」に該当するか否かを判定する（ステップＳ２２）。ステップＳ２２の判定では、左側領域５が明るい領域であり、右側領域６が暗い領域であれば、着目点４が第１境部に該当することになる。ステップＳ２２の判定で用いる所定値や判定式などは検知基準情報３ｅとして記憶部３が記憶しておくと良い。 Next, the boundary detection unit 2f determines whether or not the point of interest 4 corresponds to “a first boundary that is a boundary where the first region changes to a second region darker than the first region” (step S22). ). In the determination in step S22, if the left region 5 is a bright region and the right region 6 is a dark region, the point of interest 4 corresponds to the first boundary. The storage unit 3 may store the predetermined value and the determination formula used in the determination in step S22 as the detection reference information 3e.
　例えば、左側領域５の平均画素値が右側領域６の平均画素値より所定値以上大きい場合に着目点４が第１境部に該当すると判定することができる。また、例えば、左側領域５の中央画素値が右側領域６の中央画素値より所定値以上大きい場合に着目点４が第１境部に該当すると判定することができる。また、テープが貼られている領域は濃度むらが小さく画素値の分散が小さくなることを考慮して、左側領域５の平均画素値が右側領域６の平均画素値より所定値以上大きい場合や左側領域５の中央画素値が右側領域６の中央画素値より所定値以上大きい場合であっても、右側領域６の画素値の分散が所定値以上である場合は着目点４が第１境部に該当しないと判定しても良い。 For example, when the average pixel value of the left region 5 is larger than the average pixel value of the right region 6 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the first boundary. For example, when the central pixel value of the left region 5 is larger than the central pixel value of the right region 6 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the first boundary. Also, in consideration of the fact that the area where the tape is affixed has less density unevenness and the dispersion of pixel values becomes smaller, the average pixel value of the left area 5 is larger than the average pixel value of the right area 6 by a predetermined value or Even when the central pixel value of the region 5 is larger than the central pixel value of the right region 6 by a predetermined value or more, if the variance of the pixel values of the right region 6 is not less than the predetermined value, the point of interest 4 becomes the first boundary. You may determine that it does not apply.
　着目点４が「第１領域から第１領域よりも暗い第２領域に変化する境である第１境部」に該当すると判定された場合（ステップＳ２２のＹＥＳ）、境部検知部２ｆは、着目点４を第１境部とする（ステップＳ２３）。 When it is determined that the point of interest 4 corresponds to “a first boundary portion that is a boundary where the first region changes to a second region that is darker than the first region” (YES in step S22), the boundary detection unit 2f The point of interest 4 is set as the first boundary (step S23).
　一方、着目点４が「第１領域から第１領域よりも暗い第２領域に変化する境である第１境部」に該当しないと判定された場合（ステップＳ２２のＮＯ）、着目点４が「第３領域から第３領域よりも明るい第４領域に変化する境である第２境部」に該当するか否かを判定する（ステップＳ２４）。ステップＳ２４の判定では、左側領域５が暗い領域であり、右側領域６が明るい領域であれば、着目点４が第２境部に該当することになる。ステップＳ２４の判定で用いる所定値や判定式などは検知基準情報３ｅとして記憶部３が記憶しておくと良い。 On the other hand, when it is determined that the point of interest 4 does not correspond to the “first boundary portion that is a boundary changing from the first region to the second region darker than the first region” (NO in step S22), the point of interest 4 is It is determined whether or not a “second boundary portion that is a boundary changing from the third region to the fourth region brighter than the third region” is satisfied (step S24). In the determination of step S24, if the left area 5 is a dark area and the right area 6 is a bright area, the point of interest 4 corresponds to the second boundary. The storage unit 3 may store the predetermined value and the determination formula used in the determination in step S24 as the detection reference information 3e.
　例えば、右側領域６の平均画素値が左側領域５の平均画素値より所定値以上大きい場合に着目点４が第２境部に該当すると判定することができる。また、例えば、右側領域６の中央画素値が左側領域５の中央画素値より所定値以上大きい場合に着目点４が第２境部に該当すると判定することができる。また、テープが貼られている領域は濃度むらが小さく画素値の分散が小さくなることを考慮して、右側領域６の平均画素値が左側領域５の平均画素値より所定値以上大きい場合や右側領域６の中央画素値が左側領域５の中央画素値より所定値以上大きい場合であっても、左側領域５の画素値の分散が所定値以上である場合は着目点４が第２境部に該当しないと判定しても良い。 For example, when the average pixel value of the right area 6 is larger than the average pixel value of the left area 5 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the second boundary. For example, when the central pixel value of the right region 6 is larger than the central pixel value of the left region 5 by a predetermined value or more, it can be determined that the point of interest 4 corresponds to the second boundary. Further, in consideration of the fact that the area where the tape is applied is less uneven in density and the dispersion of pixel values is smaller, the average pixel value in the right area 6 is larger than the average pixel value in the left area 5 by a predetermined value or on the right side. Even when the center pixel value of the region 6 is larger than the center pixel value of the left region 5 by a predetermined value or more, if the variance of the pixel values of the left region 5 is greater than or equal to the predetermined value, the attention point 4 becomes the second boundary. You may determine that it does not apply.
　着目点４が「第３領域から第３領域よりも明るい第４領域に変化する境である第２境部」に該当すると判定された場合（ステップＳ２４のＹＥＳ）、境部検知部２ｆは、着目点４を第２境部とする（ステップＳ２５）。 When it is determined that the point of interest 4 corresponds to the “second boundary that changes from the third region to the fourth region brighter than the third region” (YES in step S24), the boundary detection unit 2f The point of interest 4 is set as the second boundary (step S25).
　一方、着目点４が「第３領域から第３領域よりも明るい第４領域に変化する境である第２境部」に該当しないと判定された場合（ステップＳ２４のＮＯ）、そのままフローを終了する。 On the other hand, when it is determined that the point of interest 4 does not correspond to the “second boundary portion that changes from the third region to the fourth region brighter than the third region” (NO in step S24), the flow ends. To do.
　その後、着目点４を１画素分横方向にスライドさせながら、上述した境部検知処理を繰り返す。全ての着目点４に対して境部検知処理が終了すると、境部検知部２ｆはステップＳ２３およびステップＳ２５で定めた第１境部および第２境部の情報を判定部２ｇに出力する。 Thereafter, the boundary detection process described above is repeated while the point of interest 4 is slid horizontally by one pixel. When the boundary detection processing is completed for all the points of interest 4, the boundary detection unit 2f outputs information on the first boundary and the second boundary determined in steps S23 and S25 to the determination unit 2g.
　図１３の説明に戻り、判定部２ｇについて説明する。 Returning to the description of FIG. 13, the determination unit 2g will be described.
　判定部２ｇは、境部検知部２ｆによって検知された第１境部および第２境部を用いて、　第１境部と第１境部よりも右側に位置する第２境部との間の領域に位置する画素の画素値に基づいて、第１境部と第１境部よりも右側に位置する第２境部の間の領域にテープが貼られているかを判定する。 The determination unit 2g uses the first boundary part and the second boundary part detected by the boundary part detection part 2f, and is between the first boundary part and the second boundary part located on the right side of the first boundary part. Based on the pixel value of the pixel located in the area, it is determined whether or not the tape is applied to the area between the first boundary and the second boundary located on the right side of the first boundary.
　判定部２ｇが実行する判定処理について図１６のフローチャートを用いて説明する。 Determination processing executed by the determination unit 2g will be described with reference to the flowchart of FIG.
　まず判定部２ｇは、第１境部と第２境部の全組合せの中から、左側テープ側方端と右側テープ側方端の組合せになり得る第１境部と第２境部の組合せを抽出する（ステップＳ３１）。本実施形態では、　第１境部と第１境部よりも右側に位置する第２境部との組合せを抽出し、さらに第１境部と第１境部よりも右側に位置する第２境部との間の間隔が判定対象であるテープの最小幅以上であり最大幅以下である組合せに限定して抽出する。このように第１境部と第２境部の組合せを判定対象であるテープの幅を考慮して絞り込むので、判定時間の短縮や誤検知の防止を図ることができる。 First, the determination unit 2g selects a combination of the first boundary and the second boundary that can be a combination of the left tape side end and the right tape side end from all combinations of the first boundary portion and the second boundary portion. Extract (step S31). In the present embodiment, a combination of the first boundary and the second boundary located on the right side of the first boundary is extracted, and further the second boundary located on the right side of the first boundary and the first boundary. Extraction is limited to combinations in which the interval between the parts is not less than the minimum width of the tape to be determined and not more than the maximum width. As described above, the combination of the first boundary portion and the second boundary portion is narrowed down in consideration of the width of the tape to be determined, so that the determination time can be shortened and erroneous detection can be prevented.
　次に判定部２ｇは、ステップＳ３１で抽出した組合せから或る一つの組合せに着目し、着目した第１境部と第２境部の間がテープ貼付部に該当するか否かを判定する（ステップＳ３２）。ステップＳ３２の判定で用いる所定値や判定式などは判定基準情報３ｆとして記憶部３が記憶しておくと良い。 Next, the determination unit 2g pays attention to a certain combination from the combinations extracted in step S31, and determines whether or not the focused first and second boundary portions correspond to the tape application portion ( Step S32). The storage unit 3 may store the predetermined value and the determination formula used in the determination in step S32 as the determination reference information 3f.
　例えば、着目した第１境部と第２境部の間の領域に位置する画素の平均画素値が所定値未満である場合に、着目した第１境部と第２境部の間がテープ貼付部に該当すると判定することができる。また例えば、着目した第１境部と第２境部の間の領域に位置する画素の中央画素値が所定値未満である場合に、着目した第１境部と第２境部の間がテープ貼付部に該当すると判定することができる。また例えば、着目した第１境部と第２境部の間の領域の画素値の分散が所定値未満である場合に、着目した第１境部と第２境部の間がテープ貼付部に該当すると判定することができる。 For example, when the average pixel value of the pixels located in the region between the first boundary and the second boundary is less than a predetermined value, a tape is applied between the first boundary and the second boundary. Can be determined to fall under the category. Further, for example, when the central pixel value of the pixel located in the region between the focused first boundary and the second boundary is less than a predetermined value, the tape between the focused first boundary and the second boundary is tape. It can be determined that it corresponds to the pasting part. For example, when the variance of the pixel values in the region between the first boundary and the second boundary is less than a predetermined value, the area between the first boundary and the second boundary is the tape application portion. It can be determined that this is the case.
　ここで、判別対象となる紙幣の背景画素値が一様で無い場合が考えられる。そして、背景濃度が一様でない場所にテープが貼付された場合の画素値分布は図１７のようになるので、第１境部および第２境部の検知条件を厳しくすると、第１境部または第２境部が検知できなくなるおそれがある。一方、第１境部および第２境部の検知条件を緩くすると、図１８に示すような背景濃度が一様でない場所にインク滲みがある場合の画素値分布であっても第１境部および第２境部が検知されてしまうことになる。 Here, there may be a case where the background pixel values of the banknotes to be discriminated are not uniform. Then, since the pixel value distribution when the tape is affixed to a place where the background density is not uniform is as shown in FIG. 17, if the detection conditions of the first boundary and the second boundary are strict, the first boundary or There is a possibility that the second boundary may not be detected. On the other hand, if the detection conditions at the first boundary and the second boundary are relaxed, the first boundary and the pixel value distribution when the background density is not uniform as shown in FIG. The second boundary will be detected.
　そこで、本実施形態では、ステップＳ３２の判定において、着目した第１境部に対応する図１５に示した左側領域５の平均画素値と着目した第２境部に対応する図１５に示した右側領域６の平均画素値の和を求め、その和から「着目した第１境部と第２境部の間の領域に位置する画素の平均画素値」を引いた値を求める。そして、その求めた値が所定値未満である場合は、着目した第１境部と第２境部の間の領域に位置する画素の平均画素値が所定値未満である場合や着目した第１境部と第２境部の間の領域に位置する画素の中央画素値が所定値未満である場合であっても、着目した第１境部と第２境部の間がテープ貼付部に該当しないと判定しても良い。 Therefore, in the present embodiment, in the determination in step S32, the average pixel value of the left region 5 shown in FIG. 15 corresponding to the focused first boundary and the right side shown in FIG. 15 corresponding to the focused second boundary. The sum of the average pixel values of the region 6 is obtained, and a value obtained by subtracting “the average pixel value of the pixels located in the region between the first boundary portion and the second boundary portion of interest” from the sum is obtained. When the obtained value is less than the predetermined value, the average pixel value of the pixels located in the region between the first boundary portion and the second boundary portion of interest is less than the predetermined value or the first of interest. Even if the central pixel value of the pixel located in the area between the boundary and the second boundary is less than the predetermined value, the area between the first boundary and the second boundary that is focused on corresponds to the tape application part You may decide not to.
　着目した第１境部と第２境部の間がテープ貼付部に該当すると判定された場合（ステップＳ３２のＹＥＳ）、判定部２ｇは、着目した第１境部と第２境部の間をテープ貼付部とする（ステップＳ３３）。 When it is determined that the area between the focused first boundary and the second boundary corresponds to the tape applying section (YES in step S32), the determination unit 2g determines the distance between the focused first boundary and the second boundary. Let it be a tape application part (step S33).
　一方、着目した第１境部と第２境部の間がテープ貼付部に該当しないと判定された場合（ステップＳ３２のＮＯ）、そのままフローを終了する。 On the other hand, when it is determined that the area between the focused first boundary and the second boundary does not correspond to the tape application part (NO in step S32), the flow is ended as it is.
　その後、着目する第１境部と第２境部を変更して上述したステップＳ３２の判定を繰り返し、ステップＳ３１で抽出した組合せ全てに対してステップＳ３２の判定を行う。 Thereafter, the first boundary portion and the second boundary portion to which attention is paid are changed, and the determination in step S32 described above is repeated, and the determination in step S32 is performed for all combinations extracted in step S31.
　上述した境部検知処理および判定処理により、エッジ点を抽出せずにテープが貼られているかを判定することができるので、貼付されたテープの側方端によって発生するエッジが鮮明でない場合でも紙葉類にテープが貼られていることを検知することができる。 The boundary detection processing and determination processing described above can determine whether the tape is applied without extracting the edge point, so even if the edge generated by the side edge of the applied tape is not clear It is possible to detect that the tape is stuck on the leaves.
　また、テープ貼付部は画素値の分散が小さく、インク滲み等の汚れは画素値の分散が大きいため、上述したステップＳ２２、Ｓ２４、Ｓ３２のいずれかにおいて画素値の分散を考慮して判定を行うことで、インク滲み等の汚れをテープの貼付であると誤検出することを防止できる。 In addition, since the pixel value distribution is small in the tape applying portion and the stain such as ink bleeding has a large pixel value distribution, the determination is performed in consideration of the pixel value distribution in any of the above-described steps S22, S24, and S32. Accordingly, it is possible to prevent erroneous detection of contamination such as ink bleeding as tape sticking.
　紙幣判別装置２０は、エッジ点を抽出して紙幣にテープが貼られていることを検知できる機能と、エッジ点を抽出しなくても紙幣にテープが貼られていることを検知できる機能とを搭載した装置であったが、本実施形態において詳細に説明したエッジ点を抽出しなくても紙幣にテープが貼られていることを検知できる機能は、エッジ点を抽出して紙幣にテープが貼られていることを検知できる機能とは無関係に単独で実施することも可能である。 The bill discriminating device 20 has a function capable of detecting that the tape is stuck on the bill by extracting the edge point, and a function capable of detecting that the tape is stuck on the bill without extracting the edge point. Although it was an installed device, the function that can detect that the tape is stuck on the banknote without extracting the edge point explained in detail in the present embodiment is that the edge point is extracted and the tape is stuck on the banknote. It is also possible to carry out the function independently regardless of the function that can detect that it has been detected.
　また、本実施形態において詳細に説明したエッジ点を抽出しなくても紙幣にテープが貼られていることを検知できる機能と、機械式の厚み検知を行ってテープが貼られていることを検知できる機能とを組み合わせて実施しても良い。 Moreover, even if it does not extract the edge point demonstrated in detail in this embodiment, the function which can detect that the tape is affixed on a banknote, and a mechanical thickness detection are performed, and it detects that the tape is affixed You may implement in combination with the function which can be performed.
　機械式の厚み検知を行って紙葉類にテープが貼られていることを検知できる厚みセンサの欠点として、紙葉類の前端部は厚みセンサに突入したときの衝撃によって本来の厚みよりも大きな厚みが検知されてしまうため、薄いテープで無くても紙葉類の前端部にテープが貼られているか否かを判定することができないという問題があった。 As a disadvantage of thickness sensors that can detect that the tape is stuck on the paper sheet by performing mechanical thickness detection, the front edge of the paper sheet is larger than the original thickness due to the impact when entering the thickness sensor Since the thickness is detected, there is a problem that it is not possible to determine whether or not the tape is stuck on the front end portion of the paper sheet even if it is not a thin tape.
　そこで、本実施形態において詳細に説明したエッジ点を抽出しなくても紙幣にテープが貼られていることを検知できる機能によって、紙葉類の前端部にテープが貼付されているか否かを判定し、機械式の厚み検知を行ってテープが貼られていることを検知できる機能によって、紙葉類の前端部以外の部分にテープが貼付されているか否かを判定すれば良い。 Therefore, it is determined whether or not the tape is stuck on the front end portion of the paper sheet by the function that can detect that the tape is stuck on the banknote without extracting the edge point described in detail in the present embodiment. Then, it is only necessary to determine whether or not the tape is stuck to a portion other than the front end portion of the paper sheet by a function capable of detecting that the tape is stuck by performing mechanical thickness detection.
　　　１　イメージラインセンサ部
　　　２　制御部
　　　２ａ　金種識別部
　　　２ｂ　画像データ取得部
　　　２ｃ　エッジ点抽出部
　　　２ｄ　残存エッジ点抽出部
　　　２ｅ　解析部
　　　２ｆ　境部検知部
　　　２ｇ　判定部
　　　３　記憶部
　　　３ａ　金種識別テンプレート
　　　３ｂ　フィルタ群
　　　３ｃ　参照エッジ点
　　　３ｄ　解析基準情報
　　　３ｅ　検知基準情報
　　　３ｇ　判定基準情報
　　　１０、２０　紙葉類判別装置 DESCRIPTION OF SYMBOLS 1 Image line sensor part 2 Control part 2a Denomination identification part 2b Image data acquisition part 2c Edge point extraction part 2d Remaining edge point extraction part 2e Analysis part 2f Boundary part detection part 2g Judgment part 3 Storage part 3a Denomination identification template 3b Filter Group 3c Reference edge point 3d Analysis standard information 3e Detection standard information 3g Judgment standard information 10, 20 Paper sheet discrimination device

Claims (9)

  1. 　紙葉類の撮像画像に基づいて紙葉類にテープが貼られているかを判別する紙葉類判別装置であって、
    　正当な紙葉類の撮像画像に含まれる前記正当な紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点である参照エッジ点を記憶する記憶部と、
    　判別対象となる紙葉類の撮像画像から前記判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点を抽出するエッジ点抽出部と、
    　前記エッジ点抽出部によって抽出されたエッジ点から、前記参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いて残存エッジ点を抽出する残存エッジ点抽出部と、
    　前記残存エッジ点に基づいて前記判別対象となる紙葉類にテープが貼られているかを解析する解析部と
    　を備えたことを特徴とする紙葉類判別装置。     A paper sheet discriminating apparatus that discriminates whether a tape is stuck on a paper sheet based on a captured image of the paper sheet,
    A storage unit that stores a reference edge point that is an edge point of a density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the legitimate paper sheet;
    An edge point extraction unit that extracts edge points of a density gradient direction range along a longitudinal direction of the paper sheet to be determined from a captured image of the paper sheet to be determined;
    From the edge points extracted by the edge point extraction unit, it is estimated that the edge points corresponding to the reference edge points and pixels not included in the captured image of the legitimate paper sheet are generated due to a bright region. A residual edge point extraction unit that removes edge points and extracts residual edge points;
    A paper sheet discriminating apparatus comprising: an analysis unit that analyzes whether or not a tape is affixed to the paper sheet to be discriminated based on the remaining edge point.
  2. 　前記参照エッジ点は、
    　前記正当な紙葉類の撮像画像に含まれる第１濃度勾配方向範囲のエッジ点である第１参照エッジ点と、前記第１濃度勾配方向範囲と逆方向である第２濃度勾配方向範囲のエッジ点である第２参照エッジ点とを含み、
    　前記エッジ点抽出部は、
    　前記判別対象となる紙葉類の撮像画像から前記第１濃度勾配方向範囲のエッジ点および前記第２濃度勾配方向範囲のエッジ点を抽出し、
    　前記残存エッジ点は、
    　前記エッジ点抽出部によって抽出された前記第１濃度勾配方向範囲のエッジ点から、前記第１参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いた第１残存エッジ点と、前記エッジ点抽出部によって抽出された前記第２濃度勾配方向範囲のエッジ点から、前記第２参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いた第２残存エッジ点とを含むことを特徴とする請求項１に記載の紙葉類判別装置。     The reference edge point is
    A first reference edge point that is an edge point of a first density gradient direction range and an edge of a second density gradient direction range that is opposite to the first density gradient direction range included in the captured image of the legitimate paper sheet. A second reference edge point that is a point,
    The edge point extraction unit
    Extracting an edge point of the first density gradient direction range and an edge point of the second density gradient direction range from the captured image of the paper sheet to be determined;
    The remaining edge point is
    From the edge points in the first density gradient direction range extracted by the edge point extraction unit, the edge points corresponding to the first reference edge points and pixels not included in the captured image of the legitimate paper sheet are bright. From the first remaining edge point obtained by removing the edge point estimated to have occurred due to the region and the edge point of the second density gradient direction range extracted by the edge point extraction unit to the second reference edge point Including a corresponding edge point and a second remaining edge point obtained by removing an edge point estimated that a pixel not included in the captured image of the legitimate paper sheet is generated due to a bright region. The paper sheet discrimination apparatus according to claim 1.
  3. 　前記解析部は、
    　所定サイズ領域における前記残存エッジ点の密度に基づいて前記判別対象となる紙葉類にテープが貼られているかを解析することを特徴とする請求項１または請求項２に記載の紙葉類判別装置。     The analysis unit
    The paper sheet discrimination according to claim 1 or 2, wherein whether or not a tape is stuck on the paper to be discriminated is analyzed based on a density of the remaining edge points in a predetermined size region. apparatus.
  4. 　前記残存エッジ点抽出部は、
    　前記判別対象となる紙葉類の撮像画像に、前記正当な紙葉類の撮像画像に含まれていない前記判別対象となる紙葉類の短手方向に沿った画素が明るい細線状領域が存在していると推定した場合に、前記細線状領域の周囲に位置するエッジ点も前記エッジ点抽出部によって抽出されたエッジ点から取り除くことを特徴とする請求項１～３のいずれか一項に記載の紙葉類判別装置。     The remaining edge point extraction unit includes:
    In the captured image of the paper sheet to be identified, there is a thin line-shaped region where pixels along the short direction of the paper sheet to be identified that are not included in the captured image of the legitimate paper sheet are bright The edge point located around the fine line area is also removed from the edge point extracted by the edge point extraction unit when it is estimated that The paper sheet discrimination device according to the description.
  5. 　前記判別対象となる紙葉類の撮像画像において、前記判別対象となる紙葉類の長手方向の一端から他端に向かう方向で、第１領域から前記第１領域よりも暗い第２領域に変化する境である第１境部および第３領域から前記第３領域よりも明るい第４領域に変化する境である第２境部を検知する検知部と、
    　前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域に位置する画素の画素値に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定する判定部と
    　を備えたことを特徴とする請求項１～４のいずれか一項に記載の紙葉類判別装置。     In the captured image of the paper sheet to be discriminated, the first area is changed to a second area that is darker than the first area in a direction from one end to the other end in the longitudinal direction of the paper to be discriminated. A detection unit that detects a second boundary portion that is a boundary that changes from a first boundary portion and a third region that are boundaries to the fourth region that is brighter than the third region;
    Based on a pixel value of a pixel located in a region between the first boundary and the second boundary located on the other end side from the first boundary, the first boundary and the first 5. A determination unit for determining whether a tape is applied to a region between the second boundary portion located on the other end side of the boundary portion. The paper sheet discrimination apparatus according to one item.
  6. 　前記判定部は、
    　前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の間隔が判定対象であるテープの最小幅以上であり最大幅以下である場合にのみ、
    　前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域に位置する画素の画素値に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定することを特徴とする請求項５に記載の紙葉類判別装置。     The determination unit
    Only when the interval between the first boundary and the second boundary located on the other end side from the first boundary is not less than the minimum width of the tape to be determined and not more than the maximum width. ,
    Based on a pixel value of a pixel located in a region between the first boundary and the second boundary located on the other end side from the first boundary, the first boundary and the first 6. The paper sheet discriminating apparatus according to claim 5, wherein it is determined whether or not a tape is applied to a region between the second boundary portion located on the other end side with respect to the boundary portion.
  7. 　前記判定部は、
    　前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域に位置する画素の画素値の分散に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定することを特徴とする請求項５または請求項６に記載の紙葉類判別装置。     The determination unit
    Based on the dispersion of pixel values of pixels located in a region between the first boundary and the second boundary located on the other end side from the first boundary, the first boundary and the 7. The paper sheet according to claim 5, wherein it is determined whether a tape is applied to a region between the second boundary portion located on the other end side with respect to the first boundary portion. Classification device.
  8. 　前記判定部は、
    　前記第１領域の画素値および前記第４領域の画素値に基づいて、前記第１境部と前記第１境部よりも前記他端側に位置する前記第２境部との間の領域にテープが貼られているかを判定することを特徴とする請求項５～７のいずれか一項に記載の紙葉類判別装置。     The determination unit
    Based on the pixel value of the first region and the pixel value of the fourth region, the region between the first boundary and the second boundary located on the other end side of the first boundary The paper sheet discriminating apparatus according to any one of claims 5 to 7, wherein it is determined whether a tape is stuck.
  9. 　紙葉類の撮像画像に基づいて紙葉類にテープが貼られているかを判別する紙葉類判別方法であって、
    　判別対象となる紙葉類の撮像画像から前記判別対象となる紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点を抽出するエッジ点抽出工程と、
    　前記エッジ点抽出工程によって抽出されたエッジ点から、正当な紙葉類の撮像画像に含まれる前記正当な紙葉類の長手方向に沿った濃度勾配方向範囲のエッジ点である参照エッジ点に対応するエッジ点および前記正当な紙葉類の撮像画像に含まれていない画素が明るい領域に起因して発生したと推定したエッジ点を取り除いて残存エッジ点を抽出する残存エッジ点抽出工程と、
    　前記残存エッジ点に基づいて前記判別対象となる紙葉類にテープが貼られているかを解析する解析工程と
    　を備えたことを特徴とする紙葉類判別方法。     A paper sheet discriminating method for discriminating whether a tape is stuck on a paper sheet based on a captured image of the paper sheet,
    An edge point extracting step of extracting edge points of a density gradient direction range along a longitudinal direction of the paper sheet to be determined from a captured image of the paper sheet to be determined;
    Corresponding to a reference edge point that is an edge point in a density gradient direction range along the longitudinal direction of the legitimate paper sheet included in the captured image of the legitimate paper sheet from the edge point extracted by the edge point extraction step A remaining edge point extracting step of extracting the remaining edge point by removing the edge point estimated that the edge point and the pixel not included in the captured image of the legitimate paper sheet are generated due to a bright region;
    An analysis step of analyzing whether a tape is stuck on the paper sheet to be determined based on the remaining edge point.
PCT/JP2016/058188 2015-03-31 2016-03-15 Paper sheet detection device and paper sheet detection method WO2016158392A1 (en)

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