JP5572450B2 - Deformed coin discrimination method and coin processing apparatus - Google Patents

Description

  The present invention relates to a deformed coin discriminating method and a coin processing device that detect a deformed coin, and in particular, reduces the manufacturing cost of the coin processing device, and downsizes a coin identifying portion that performs coin recognition and a coin processing device housing. The present invention relates to a deformed coin discriminating method and a coin processing device that can detect deformed coins with high accuracy.

  2. Description of the Related Art Conventionally, there is known a deformed coin discriminating method in which an image of a coin is captured by a camera, a deformation level of the coin is determined based on the captured image, and whether or not the coin is a deformed coin is determined based on the determined deformation level. .

  For example, Patent Document 1 discloses a deformed coin discriminating method for discriminating whether or not a coin is a deformed coin based on a ratio between a major axis and a minor axis based on an image captured by a camera. Patent Document 1 also discloses a deformed coin discriminating method that detects the height of a coin with an optical thickness sensor and discriminates whether or not the coin is a deformed coin based on the detected height.

  In such a deformed coin discrimination method, when the ratio of the major axis and the minor axis is equal to or greater than a predetermined threshold, or when the detected coin height is equal to or greater than the predetermined threshold, it is determined that the coin is a deformed coin. The deformed coin discrimination method also determines whether or not the coin is a fake coin, that is, “true coin” or “fake coin” based on an image captured by the camera.

JP 2000-251109 A

  However, the coin processing device to which the conventional deformed coin discriminating method is applied has a problem that the size of the coin discriminating portion for discriminating the coin cannot be reduced. Specifically, since the conventional coin processing apparatus needs to include a magnetic sensor for identifying the denomination and an optical thickness sensor, the coin identifying portion inevitably becomes large.

  Moreover, the coin processing apparatus to which the conventional deformed coin discrimination method is applied has a large coin identification portion and a large casing of the coin processing apparatus. Thereby, the manufacturing cost concerning an apparatus will also swell. Moreover, the conventional coin processing apparatus will also cost for providing a magnetic sensor and a thickness sensor.

  Furthermore, the conventional coin processing apparatus has a problem that accuracy is poor because it is a technique for discriminating deformed coins based only on the ratio of the major axis and the minor axis.

  From these things, while reducing the manufacturing cost concerning a coin processing apparatus, the deformation | transformation coin discriminating method which can detect a deformation | transformation coin with high precision, reducing the coin identification part which performs a coin identification, and the housing | casing of a coin processing apparatus, and How to realize a coin processing device is a big issue.

  The present invention has been made in order to solve the above-described problems caused by the prior art, and reduces the manufacturing cost of the coin processing device and provides a coin identifying portion for performing coin identification and a housing for the coin processing device. An object of the present invention is to provide a deformed coin discriminating method and a coin processing device capable of detecting a deformed coin with high accuracy while being downsized.

In order to solve the above-described problems and achieve the object, the present invention is a deformed coin discrimination method applied to a coin processing device that detects a deformed coin, and an image acquisition step of acquiring an image of the coin; A center setting step for setting the center of the coin based on the characteristics of the image acquired by the image acquisition step, and a polar coordinate image acquisition for acquiring a polar coordinate transformed image for the center of the coin set by the center setting step A step of identifying the denomination of the coin based on the characteristics of the image acquired by the polar coordinate image acquisition step, and a trajectory of the outer periphery of the coin based on the image acquired by the polar coordinate image acquisition step of the deficiency amount detection step of detecting a defect amount, the hardness identified the deficiency amount detected by the deficiency detecting step and by the identification step Characterized in that it includes a determination step of determining whether the coin is deformed based on each of the denomination and the threshold stored in advance.

  Further, in the present invention according to the above invention, in the above-described invention, in the center setting step, the outer peripheral portion detected from an image obtained by performing polar coordinate conversion on a temporary center set based on the feature of the image acquired by the image acquisition step Based on the trajectory, the temporary center is corrected to a true center.

Further, the present invention is characterized in that, in the above-mentioned invention, the defect amount detecting step uses a defect length of an outer periphery orbit in the coin as the defect amount of the outer periphery orbit.

Further, the present invention is used in the above invention, the deficiency detecting step, a deficiency of the trajectory of the outer peripheral portion, a defect angle indicated the lost portion of the trajectory of the outer peripheral portion of the coin in the inner angle of a circular arc characterized in that it.

Further, the present invention is a coin processing device that detects a deformed coin, and sequentially conveys the coins on a conveyance path, and conveys the coins while pressing the coins with a belt-like pressing mechanism; Polar coordinates for the center of the coin set by the center setting means, image setting means for acquiring an image, center setting means for setting the center of the coin based on the characteristics of the image acquired by the image acquiring means Polar coordinate image acquisition means for acquiring the converted image, identification means for identifying the type of the coin based on the characteristics of the image acquired by the polar coordinate image acquisition means, and deformation determined for each denomination of the coin storage means for storing a threshold value for determining that the outer peripheral portion of the coin based on the image acquired by the polar coordinate image acquisition unit A defect detecting means for detecting the amount of missing track, reads a threshold value corresponding to the denomination of the coins identified from said storage means by said identification means, which is detected by the read-out threshold and the deficiency amount detecting means discriminating means for discriminating whether or not the coin is deformed on the basis of said vacancies, said housing part the coin based on the determination result determined by the identified identification result and the determination means by the identification means Alternatively, a sorting means for sorting into the return port is provided.

According to the present invention, a deformed coin discrimination method applied to a coin processing device that detects a deformed coin, acquiring an image of a coin, setting the center of the coin based on the characteristics of the acquired image, An image obtained by converting polar coordinates about the set center of the coin is acquired, and the denomination of the coin is identified based on the characteristics of the acquired image, and the missing amount of the trajectory of the outer peripheral portion of the coin based on the acquired image And determining whether or not the coin is deformed based on the detected amount of loss and the threshold value stored in advance for each of the identified coin denominations. In addition to reducing the manufacturing cost of the applied coin processing apparatus, it is possible to detect a deformed coin with high accuracy while reducing the size of the coin identifying portion for performing coin identification and the housing of the coin processing apparatus. In particular, it is possible to include a difference in deformation rate depending on the characteristics of each denomination of coins, and it is possible to detect a deformed portion with higher accuracy.

  According to the present invention, the temporary center is corrected to the true center based on the trajectory of the outer peripheral portion detected from the image obtained by polar-coordinate conversion with respect to the temporary center set based on the characteristics of the acquired image. Therefore, when detecting the deformed portion, the outer peripheral portion detected based on the corrected center becomes a straight line, and there is an effect that the deformed portion can be detected with high accuracy.

In addition, according to the present invention, since the defect length of the outer peripheral track in the coin is used as the defect amount of the outer peripheral track, it is possible to detect the deformed portion with high accuracy.

Further, according to the present invention, as the amount of missing raceway of the outer peripheral portion, so it was decided to use a deficiency angle indicated by the internal angle of the lost portion of the trajectory of the outer peripheral portion and the arc of the coin, accurately detected deformations There is an effect that can be done.

Moreover, according to the present invention, a coin processing device that detects a deformed coin, sequentially conveys coins on a conveyance path, conveys the coins while pressing the coins with a belt-like pressing mechanism, and acquires an image of the coins. The center of the coin is set based on the acquired feature of the image, the image obtained by polar coordinate conversion is acquired about the set center of the coin, the type of the coin is identified based on the acquired feature of the image, and the acquired Based on the image, the missing amount of the orbit of the outer periphery of the coin is detected, the threshold corresponding to the identified coin is read, and whether the coin is deformed based on the read threshold and the detected missing amount And the coins are sorted into the storage unit or the return port based on the identified identification result and / or the discrimination result discriminated by the discriminating means. It is possible to transport one by one on the road is an effect that it is possible to prevent the floating of the coin. In addition to this, not only the deformed coins are not accidentally paid out, but also the occurrence of troubles due to coin clogging or the like of the coin processing device is reduced, so that it is not inconvenienced for users of the coin processing device. There is an effect of not incurring profits.

FIG. 1 is a diagram showing an outline of a deformed coin discrimination method according to the present invention. FIG. 2 is a block diagram illustrating the configuration of the coin processing device according to the present embodiment. FIG. 3 is a diagram illustrating an example of threshold information. FIG. 4 is a side view of the coin processing device. FIG. 5 is a diagram for explaining a temporary center setting method. FIG. 6 is a diagram illustrating an example of cutting out a partial image. FIG. 7 is a diagram for explaining polar coordinate conversion processing of a partial image. FIG. 8 is a diagram for explaining a center position correction method. FIG. 9 is a diagram illustrating an example of a temporary center correction method. FIG. 10 is a flowchart showing a modified coin discrimination processing procedure executed by the coin processing device.

  Exemplary embodiments of a deformed coin discrimination method and a coin processing device according to the present invention will be described below in detail with reference to the accompanying drawings. First, prior to detailed description of the embodiment, an outline of the modified coin discrimination method according to the present invention will be described with reference to FIG.

  In the deformed coin discriminating method according to the present invention, when a coin is deformed, it is a deformed coin depending on the length of the deformed portion (hereinafter referred to as “defect length”) or the defect angle included in the image of the outer periphery. The main feature is in determining whether or not. The missing angle is an inner angle of an arc formed by connecting both ends of the deformed portion and the center of the coin.

  The coin processing apparatus to which the deformed coin discriminating method according to the present invention is applied calculates the ratio between the missing length and the outer peripheral length of the coin or the missing angle, and discriminates whether the coin is a deformed coin based on the calculated ratio. Here, the case where the defect length is used will be described, but the same applies to the case where the defect angle is used. Below, the outline | summary is demonstrated about the deformation | transformation coin discrimination | determination method based on this invention using FIG.

  FIG. 1 is a diagram showing an outline of a deformed coin discrimination method according to the present invention. As shown in FIG. 1A, first, the coin processing device to which the modified coin discrimination method according to the present invention is applied picks up an image of a coin (see (1) in FIG. 1), and the picked-up image. The denomination and the like are identified based on the characteristics (see (2) in FIG. 1).

  Specifically, the coin processing device identifies the denomination and front and back according to the size and pattern of the coins shown in the image, and corrects by the identification process such as comparing with a standard image prepared for each denomination. It also identifies whether it is a currency or counterfeit.

  Here, when the coin is deformed due to distortion or loss, an image in which a part of the outer peripheral portion is lost is captured. For example, as shown in FIG. 1A, the lower right missing portion is an image of the deformed portion.

  Subsequently, the coin processing device cuts out an image of the coin surrounded by two concentric circles as shown by the broken line in FIG. 1B (see (3) in FIG. 1). Note that the diameters of the two concentric circles are adjusted so that the cut out partial image includes at least the outer peripheral portion of the coin.

  Then, as shown in FIG. 1C, the coin processing device performs polar coordinate conversion on the cut-out partial image, and deletes the image from the image converted from the polar coordinate format onto the two-dimensional orthogonal coordinate plane. Detect the length. In FIG. 1C, an arrow indicating the center direction of the coin is shown together with the image subjected to polar coordinate conversion.

  Thereafter, the coin processing device determines whether or not the coin is a deformed coin based on the detected defect length and the peripheral length for each denomination prepared in advance (see (4) in FIG. 1). Specifically, in the coin processing device, when the value obtained by dividing the defect length by the outer peripheral length (hereinafter referred to as “defect length ratio”) exceeds a predetermined threshold, it is determined as a deformed coin.

  As described above, in the coin processing device to which the deformed coin discrimination method according to the present invention is applied, it is accurately determined whether or not the coin is a deformed coin by the defect length indicating the deformed portion of the imaged coin and the outer peripheral length for each denomination. Can be determined.

  Below, the Example about the coin processing apparatus to which the deformation | transformation coin discrimination | determination method demonstrated using FIG. 1 is applied is described in detail. First, the structure of the coin processing apparatus 10 according to the present embodiment will be described with reference to FIG.

  FIG. 2 is a block diagram illustrating the configuration of the coin processing device according to the present embodiment. In FIG. 2, only constituent elements necessary for explaining the characteristic points of the coin processing apparatus 10 are extracted and shown.

  The coin processing device 10 includes an imaging unit 11, a reject unit 12, a storage unit 13, a storage unit 14, and a control unit 15. The storage unit 14 stores image information 14a, standard image information 14b, and threshold information 14c, and the control unit 15 includes an image acquisition unit 15a, an outer periphery cutout unit 15b, and a denomination identification unit 15c. The defect length detecting unit 15d and the deformed coin discriminating unit 15e are further provided.

  The imaging unit 11 receives a light irradiation device that irradiates one or a plurality of light sources among visible light and infrared light such as green light, and reflected light reflected from the light irradiation device on the coin. It includes a CCD (Charge Coupled Device) camera / CMOS (Complementary Metal Oxide Semiconductor) camera. And the imaging part 11 images the image of a coin, and passes the imaged image data to the image acquisition part 15a.

  The reject unit 12 is a coin return port that has been identified as a deformed coin by the deformed coin discriminating unit 15e, a coin denominated by the denomination identifying unit 15c, or a discriminating unit (not shown) that is not a normal coin.

  The storage unit 13 is a storage unit that stores coins that are determined to be normal coins by the control unit 15. A plurality of storage units 13 may be provided, and coins may be stored for each denomination in the denomination storage unit 13.

  The storage unit 14 is a storage device such as a random access memory (RAM) or a nonvolatile memory, and stores image information 14a, standard image information 14b, and threshold information 14c. The image information 14 a is image data of coins imaged by the imaging unit 11.

  The standard image information 14b is the outer peripheral length of the coin for each denomination. The deformed coin discriminating unit 15e discriminates whether or not the coin is a deformed coin based on the defect length detected by the defect length detecting unit 15d and the standard image information 14b corresponding to the denomination identified by the denomination identifying unit 15c. To do.

  The threshold value information 14c is threshold value data used in the determination of a deformed coin. The deformed coin discriminating unit 15e discriminates that the coin is a deformed coin when the calculated loss length ratio exceeds the threshold value of the threshold information 14c. Here, details of the threshold information 14c will be described with reference to FIG.

  FIG. 3 is a diagram illustrating an example of the threshold information 14c. As illustrated in FIG. 3, the threshold information 14 c includes a “denomination” item and a “threshold” item.

  For each “denomination”, a “threshold value” is set, and when the calculated loss length ratio is compared with the threshold value, a threshold value corresponding to the denomination of the coin is used. For example, since a 1-yen coin is soft and easily deformed, even if it has a certain amount of defect length, if it is not assumed to be a deformed coin, the threshold value may be set higher than other coins. .

  In addition, a coin having a larger size has a longer defect length than a coin having a smaller size even if the defect length ratio is the same. Therefore, when the same loss length is used as a deformed coin for any coin, the threshold value is set higher (longer) as the coin has a larger size.

  Thereby, in the coin processing apparatus 10, it becomes possible to include the difference of the deformation rate by the characteristic for every denomination of a coin, and it can detect a deformation | transformation part with higher precision. Note that the threshold value of the threshold information 14c may be only one type, not for each denomination.

  Returning to the description of FIG. 2, the description of the coin processing device 10 will be continued. The control unit 15 is a control unit that performs overall control of the coin processing device 10. The image acquisition unit 15 a is a processing unit that performs processing for acquiring image data of a coin imaged by the imaging unit 11 and passing it to the image information 14 a of the storage unit 14.

  The outer periphery cutout unit 15b is a processing unit that performs a process of cutting out a partial image including the outer periphery. Further, the outer peripheral cutout unit 15b performs a process of converting the cut partial image into polar coordinates based on the center set from the image information 14a.

  Specifically, the outer periphery cutout unit 15b sets a temporary center of a coin shown in the image information 14a, cuts out a partial image including the outer periphery of the image information 14a, and detects the outer periphery. Thereafter, the outer periphery cutout unit 15b corrects the center position of the coin based on the detected outer track of the outer periphery, and performs polar coordinate conversion based on the corrected center position. Here, the polar coordinate conversion is performed so that the horizontal axis represents the declination θ and the vertical axis represents the radius, and each element represents the luminance of the pixel. The details of the outer peripheral cutting method will be described later.

  The denomination identifying unit 15c is a processing unit that performs a process of identifying the denomination and the front and back of the coins based on the center position corrected by the outer peripheral cutout unit 15b and the size and pattern of the coins reflected in the image information 14a. The denomination identifying unit 15c also performs a process of identifying whether or not it is a genuine coin by comparing with a standard image for each denomination stored in the storage unit 14 in advance. The denomination identifying unit 15c may identify the denomination based on the weight or thickness of the coin.

  The missing length detection unit 15d is a processing unit that performs processing to detect the outer peripheral portion from the image that has been subjected to polar coordinate conversion by the outer peripheral portion cutout portion 15b, and to detect the detected defective length of the outer peripheral portion.

  Specifically, the missing length detection unit 15d searches for a pixel that has undergone polar coordinate conversion by the outer periphery cutout unit 15b in a predetermined direction, and when the pixel brightness exceeds a predetermined threshold for two consecutive pixels, Determine and detect. Then, the defect length detection unit 15d detects the length of the defect part indicating the deformed part from the detected outer peripheral part, that is, the defect length.

  The deformed coin discriminating unit 15e calculates a defect length ratio based on the outer peripheral length of the standard image information 14b corresponding to the denomination identified by the denomination identifying unit 15c and the defect length detected by the defect length detecting unit 15d. Is a processing unit. Specifically, the defect length ratio is a value obtained by dividing the defect length by the outer peripheral length, and is represented by Expression (1).

  Defect length ratio = Defect length / Outer circumference length (1)

  And the deformation | transformation coin discrimination | determination part 15e discriminate | determines that it is a deformation | transformation coin, when the calculated defect | deletion length ratio exceeds the threshold value of the threshold value information 14c. Moreover, the coin determined to be a deformed coin is discharged to the reject unit 12. On the other hand, the coin determined not to be a deformed coin is stored in the storage unit 13. The coins determined to be deformed coins are discharged to the reject unit 12, but may be stored in the storage unit 13 as not being recycled. In addition, a reject storage unit may be separately provided in the coin processing apparatus 10, and coins determined to be deformed coins may be sorted and stored in the reject storage unit.

  Next, in order to explain the schematic configuration of the coin processing device 10, the internal structure of the coin processing device 10 will be described with reference to FIG. FIG. 4 is a side view of the coin processing device.

  As shown in FIG. 4, the coin processing device 10 includes a substantially rectangular parallelepiped housing 20, a slot 21 for throwing coins into the inside from the outside of the casing 20, and coins thrown into the slot 21. And a supply unit 22 for supplying to a coin feeding unit 24 described later. Furthermore, the control part 15 is provided in the housing | casing 20 with which the coin processing apparatus 10 is provided, and controls each component.

  The coin processing device 10 further includes a coin feeding unit 24 that stores the coins supplied from the supply unit 22 and feeds the coins. The coin feeding unit 24 is connected to a transport unit 25 that transports the fed coins inside the housing 20.

  The conveyance unit 25 is provided with a conveyance path 26 extending in a substantially horizontal direction, and coins fed from the coin feeding unit 24 are conveyed one by one along the conveyance path 26. A belt-shaped coin pressing mechanism (not shown) is provided above the conveyance path 26 to prevent the coins conveyed on the conveyance path 26 from floating.

  An imaging unit 11 is provided on the upstream side of the transport unit 25, and an image of a coin passing through the imaging unit 11 is captured. On the other hand, a sorting unit 27 is provided on the downstream side of the transport unit 25, and coins transported from the transport unit 25 via the transport path 26 are sorted based on the identification result identified by the denomination identifying unit 15c. Are sent to the openings 28a, 28b, 28c, 28d.

  Specifically, a coin that has been identified as a modified coin by the deformed coin discriminating unit 15e, a coin that cannot be identified by the denomination identifying unit 15c, or a coin that has been identified as not being a genuine coin is rejected as a reject coin. It is discharged to the section 12.

  At that time, the reject coins are discharged to the reject unit 12 accessible from the outside of the housing 20 through the reject coin opening 28 a and the reject coin chute 31 provided below the sorting unit 27.

  Further, for each denomination identified by the denomination identifying unit 15 c, coins are stored in the denomination storing unit 13 through the openings 28 b, 28 c, 28 d provided below the sorting unit 27 and the chute 29. .

  It should be noted that although each denomination is selected and stored in the storage unit 13, a plurality of denominations may be stored in a mixed state. The coins stored in the storage unit 13 are collected by a bank clerk or the like who performs a cash collection operation by opening the door 23 of the housing 20.

  Further, a foreign matter discharge chute 30 is provided below the coin feeding unit 24, and foreign matters sent from the coin feeding unit 24 to the foreign matter discharge chute 30 are discharged to the reject unit 12 via the reject coin chute 31. Is done.

  Here, a temporary storage unit (not shown) may be provided between the openings 28b, 28c, 28d and the storage unit 13, and the coins stored in the temporary storage unit are stored in the storage unit 13 at a predetermined time. Also good.

  Thus, in the coin processing device 10, the coins inserted into the insertion slot 21 are sent to the coin feeding unit 24, and the coins fed from the coin feeding unit 24 pass through the imaging unit 11 provided on the transport path 26. After that, the sorting unit 27 sorts.

  Specifically, when the control unit 15 determines that the coin is a deformed coin, it is returned to the reject unit 12 as a reject coin, and normal coins are stored in the storage unit 13.

  Next, details of the outer periphery cutting method performed by the outer periphery cutting portion 15b will be described with reference to FIGS. First, a provisional center setting method will be described, followed by a method for cutting out an outer peripheral portion and a center position correction method.

  First, details of the provisional center setting method executed by the coin processing apparatus 10 will be described with reference to FIG. FIG. 5 is a diagram for explaining a temporary center setting method. As shown in FIG. 5, it is assumed that coins are transported in the transport direction indicated by the arrows on the transport path 26.

  First, as shown in the lower right of FIG. 5, the outer periphery cutout unit 15b creates a horizontal histogram in which the luminance of each pixel constituting the captured coin image is added in a direction parallel to the transport direction. Then, the outer periphery cutout unit 15b searches from the left and right ends of the horizontal histogram shown in FIG. 5, and when the value of the horizontal histogram exceeds a predetermined threshold (here, the threshold A), the outer periphery cutout unit 15b Part.

  In this way, the outer periphery detected when searching from the right to the left is the right outer periphery, and the outer periphery detected when searching from the left to the right is the left outer periphery. These are indicated by “triangles”.

  Next, the outer periphery cutout unit 15b creates a vertical histogram in which the luminance of each pixel constituting the captured coin image is added in a direction perpendicular to the transport direction. Here, since coins are continuously transported on the transport path, another coin may be transported by being overlapped with the front end portion or the end portion in the coin transport direction.

  An accurate outer periphery cannot be detected with the luminance of the pixels including such overlapping portions. Therefore, in order to exclude the value of the overlapping portion of coins, it is necessary to detect the outer peripheral portion with a width smaller than the maximum width of the end portion from the front end portion in the transport direction.

  Further, in order to shorten the processing time and to accurately obtain the center by excluding the reflection of the belt, the number of pixels to be added in the portion for detecting the outer peripheral portion is reduced. In consideration of the above, the outer peripheral cutout unit 15b creates a vertical histogram for each pixel in the window region shown by the rectangular parallelepiped in FIG.

  The outer periphery cutout unit 15b searches from the upper and lower ends of the vertical histogram shown in FIG. 5 and, when the value of the vertical histogram exceeds a predetermined threshold value (here, the threshold value B), the pixel is defined as the upper and lower outer periphery portions. To do. In FIG. 5, each is indicated by a “circle”.

  Then, the outer peripheral cutout portion 15b uses the midpoint between the right outer peripheral portion and the left outer peripheral portion as the coordinate of the axis perpendicular to the temporary center conveyance direction, and the midpoint between the upper outer peripheral portion and the lower outer peripheral portion as the temporary center. Set the coordinates of the axis parallel to the transport direction.

  Next, the details of the outer periphery cutting method performed by the coin processing device 10 will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram illustrating an example of cutting out a partial image, and FIG. 7 is a diagram illustrating polar coordinate conversion processing of the partial image.

  First, the partial image cut-out process will be described. The outer peripheral cutout unit 15b cuts out a partial image that is surrounded by two concentric circles centered on the temporary center and includes the outer peripheral part from the image information 14a captured by the imaging unit 11.

  For example, as shown in FIG. 6A, the cut out partial image includes the outer periphery of the largest 500 yen coin among the denominations, and as shown in FIG. The partial image to be included includes the smallest outer peripheral portion of a 1-yen coin among the denominations. In this way, the radius of the concentric circle is set so that an image including any outer peripheral portion of coins having different sizes depending on the denominations can be cut out.

  Here, as shown by the broken line in FIG. 6A, the outer periphery cutout portion 15b has a provisional center as the center of the circle and a circle with a radius of 50 pixels and a radius of 120 pixels (50 pixels + 70 pixels = 120). A partial image surrounded by a circle of pixels is cut out.

  Although the partial image surrounded by the circle having a radius of 50 pixels and the circle having a radius of 120 pixels is cut out, the maximum value and the minimum value of the coin size differ depending on the currency. It is good also as changing the radius of a concentric circle according to the currency of the country to use.

  Next, polar coordinate conversion processing of the partial image will be described with reference to FIG. 7A is a partial image to be cut out, and FIGS. 7B and 7C are images that have undergone polar coordinate conversion. The following description will be made by appropriately using coordinate axes as shown on the right side of FIG. I will do it.

  The outer periphery cutout unit 15b converts the cutout partial image (see FIG. 7A) from a format expressed in polar coordinates based on a temporary center to a two-dimensional orthogonal coordinate plane (hereinafter referred to as “polar coordinate conversion”). (Refer to FIG. 7B). Specifically, it is assumed that the X-axis of the orthogonal coordinates from the polar coordinates represented by a predetermined radius and the argument θ corresponds to the argument θ, and the Y-axis corresponds to the radius and is converted.

  Here, as shown in FIG. 7B, the negative direction of the Y-axis is the center side of the circle, and from the 50th pixel to the 120th pixel on the same diameter from the negative direction of the Y-axis to the positive direction. Image data is converted, and pixels constituting the circumference of the same radius are converted in the X-axis direction. Also, assuming that the number of pixels constituting the circumference of a predetermined radius is 512 pixels, the declination is converted at an interval of 0.703 degrees (360 ÷ 512 = 0.703). Note that the number of pixels varies depending on the accuracy of the imaging unit 11 and the like.

  Here, if all the pixel values converted into an array of 512 pixels in the X-axis direction and 71 pixels in the Y-axis direction are used, it takes time to correct the center position performed by the coin processing device 10.

  Therefore, in order to shorten the correction processing time, the outer peripheral cutout unit 15b extracts pixels at predetermined intervals for the X axis and sets them as processing targets. Here, a case will be described in which pixel values constituting the circumference of a position divided into 32 equal parts in the X-axis direction are described. However, a position that is equally divided by a predetermined number, for example, 64 equal parts may be used. .

  In this case, pixel values in the radial direction are extracted at intervals of 11.25 ° (360 ÷ 32 = 11.25). The black part in FIG. 7B indicates the pixel of the nth angle (11.25 * n °) to be extracted, where the negative end of the X axis is 0 degree.

  When extracting the pixel values of 32 equal parts, the outer periphery cutout unit 15b corrects pixel value fluctuations (hereinafter referred to as “noise”) due to dust or the like reflected together with the coin image. The following processing is performed on the pixels arranged in the axial direction.

  The outer peripheral cutout portion 15b includes two pixels adjacent to the pixel having an angle of 11.25 * n ° in the X-axis positive direction and two pixels adjacent to the X-axis negative direction (see the hatched portion in FIG. 7B). A value obtained by adding pixel values for a total of five pixels is set as a pixel value to be extracted.

  As described above, the outer peripheral cutout unit 15b extracts pixel values expressed by an array of 32 pixels in the X-axis direction and 71 pixels in the Y-axis direction from the pixel values (512 pixels × 71 pixels) subjected to the polar coordinate conversion. (Refer to FIG. 7C).

  Then, the outer peripheral cutout unit 15b searches for the luminance of each pixel from the positive direction of the Y axis toward the negative direction for one column of 71 pixels in the vertical direction, that is, the Y-axis direction, and the luminance of the image data continues at two locations. When the predetermined threshold value is exceeded, the outer peripheral portion is determined.

  The outer peripheral cutout unit 15b detects the outer peripheral part by performing the above-described determination processing on the image data for 32 locations of the X-axis width. The outer periphery cutout unit 15b determines the outer periphery when the luminance of the image data exceeds a predetermined threshold value continuously at two locations. It is good also as determining.

  Next, details of the center position correction method executed by the coin processing apparatus 10 will be described with reference to FIGS. 8 and 9. FIG. 8 is a diagram illustrating a center position correction method, and FIG. 9 is a diagram illustrating an example of a temporary center correction method.

  First, the outer periphery cutout unit 15b detects the outer periphery based on the image information 14a including the deformed portion as shown in FIG. 8A, and the temporary center is the true center position. If they are different, the detected outer peripheral portion has a trajectory as shown in FIG.

  Therefore, the outer periphery cutout portion 15b corrects the center position by substituting the value on the outer periphery orbit into the periodic function because the outer periphery orbit is represented by a predetermined periodic function. After that, the outer periphery cutout unit 15b cuts out the outer periphery again with the corrected center position.

  Specifically, the outer periphery cutout unit 15b performs the following processing. As described above, the outer peripheral portion detected by the outer peripheral cutout portion 15b has a trajectory as shown in FIG.

  However, in the case of a coin having a deformed portion, the outer peripheral portion cutout portion 15b sets an erroneous position on the outer periphery of the deformed portion as the outer peripheral portion, as in the portion surrounded by the broken line shown in FIG. It may be judged. Note that the circles shown in FIG. 8B indicate the outer peripheral portions of 32 locations determined by the outer peripheral cutout portion 15b.

  Therefore, the outer periphery cutout portion 15b obtains a reference diameter (hereinafter referred to as “reference diameter”), smoothes the outer periphery trajectory based on a predetermined periodic function represented by the reference diameter, and performs interpolation processing. (Refer to FIG. 8C).

  Here, a method for calculating the reference diameter will be described below. The outer periphery cutout portion 15b has a diameter (hereinafter referred to as “diagonal”) based on an outer periphery (hereinafter referred to as “diagonal”) having an angular difference of 180 ° with respect to the detected outer periphery. "Diagonal diameter").

  And the outer peripheral part cutout part 15b sorts the obtained 16 diagonal diameters by diameter length, calculates the average of the four center lengths, and sets it as the reference diameter length. Here, the average of the central four is calculated, but a predetermined number in the center, for example, the average of the two central may be calculated and used as the reference diameter length.

  In this way, the difference between the reference radial length calculated by the outer peripheral cutout portion 15b and the 16 diagonal radial lengths is calculated, respectively, and the trajectory of the outer peripheral portion is smoothed by the difference. Specifically, if the difference is greater than or equal to a predetermined value, the outer peripheral cutout unit 15b checks the radial length of the diagonal diameter, and if there is an abnormality in the length, estimates it from the preceding and subsequent data. Thus, the outer periphery is corrected so as to be smooth.

  Further, the outer peripheral cutout portion 15b corrects the two radii by comparing the two radii calculated for the outer peripheral portions of the opposite end portions of the diagonal diameter with the reference radial length / 2. Further, a foreign matter portion such as dust may be corrected by comparing a value obtained by integrating a predetermined periodic function with a value at the outer peripheral portion. As described above, by correcting the deformed portion included in the outer peripheral portion, the center position described later can be corrected with high accuracy.

  And the outer peripheral part cutout part 15b performs the following processes about the corrected outer peripheral part, and correct | amends a temporary center. The outer peripheral cutout portion 15b calculates the difference between the two radii calculated based on the outer peripheral portions of the opposite end portions of the diagonal diameter and the reference radial length / 2 for each of the 16 diagonal diameters. The values are added (hereinafter, this value is referred to as “amplitude sum”).

  Here, if the maximum value of the calculated amplitude sum is smaller than the predetermined value, the outer periphery cutout unit 15b determines that the correction of the center position is not necessary. Further, when the calculated maximum value of the amplitude sum is larger than the predetermined value, the outer periphery cutout unit 15b corrects the temporary center.

  Details of the temporary center correction method will be described with reference to FIG. FIG. 9 is a diagram illustrating an example of a temporary center correction method.

  As shown in FIG. 9, the outer periphery cutout portion 15b uses the set temporary center as a point A (x, y), and the two outer periphery portions where the calculated amplitude sum is maximum are points B and C. Suppose that Here, the longer length (line segment AB) from the temporary center A to the outer peripheral points B and C is rmax, and the shorter length (line AC) is rmin, and the line AB and the X axis are The argument formed is θmax, and the argument formed between the line segment AC and the X axis is θmin.

In this case, when the corrected center is (X, Y), the corrected center coordinates (X, Y) are as shown in equations (2) and (3).
X = x + (rmax−rmin) / 2 * cos (θmax) (2)
Y = y + (rmax−rmin) / 2 * sin (θmin) (3)

  In this way, the outer periphery cutout portion 15b corrects the temporary center. Returning to the description of FIG. 8, the description of the center position correction method will be continued.

  In the outer periphery cutout unit 15b, after correcting the center position, a partial image including the outer periphery is cut out again, and when the outer periphery is detected from the cut out image data, a straight line is drawn as shown in FIG. The outer peripheral portion to be detected is detected, and the defect length can be obtained with high accuracy based on the outer peripheral portion drawn in a straight line.

  In addition, although the case where the temporary center set in the outer periphery cutout part 15b is different from the true center position has been described, when the temporary center matches the true center position, the detected outer periphery is shown in FIG. Since it is drawn with a straight line as shown in (D), correction of the center position becomes unnecessary.

  Next, a modified coin discrimination processing procedure executed by the above-described coin processing device 10 will be described with reference to FIG. FIG. 10 is a flowchart showing a modified coin discrimination processing procedure executed by the coin processing device.

  As illustrated in FIG. 10, the image acquisition unit 15 a acquires an image of a coin imaged by the imaging unit 11 (step S <b> 101) and passes it to the image information 14 a of the storage unit 14.

  Thereafter, the outer periphery cutout unit 15b sets a temporary center of the coin based on the image information 14a (step S102), and cuts out the outer periphery of the coin using the temporary center (step S103).

  Then, the outer periphery cutout unit 15b corrects the center position with the outer periphery cut out at step S103 (step S104), and cuts out the outer periphery again with the corrected center (step S105).

  Subsequently, the denomination identifying unit 15c identifies the denomination and the front and back of the coin based on the center position corrected in step S104 and the size and pattern of the coin shown in the image information 14a (step S106).

  Further, the missing length detection unit 15d detects the length of the portion of the outer peripheral portion that is cut out by the outer peripheral portion cutout portion 15b, that is, the defective length (step S107).

  Then, the deformed coin discriminating unit 15e calculates a defect length ratio based on the defect length detected in step S107 and the outer peripheral length of the standard image information 14b corresponding to the denomination identified in step S106 (step S108).

  The deformed coin discriminating unit 15e determines whether or not the coin is a deformed coin based on the missing length ratio calculated in step S108 and the threshold information 14c corresponding to the denomination (step S109). When it is determined that the deformed coin is a deformed coin (step S109, Yes), the deformed coin discriminating unit 15e discharges the coin to the reject unit 12 (step S110), and ends the deformed coin discriminating process executed by the coin processing device 10. .

  On the other hand, when the deformed coin discriminating unit 15e discriminates that it is not a deformed coin but a normal coin (No at Step S109), the coin is stored in the storage unit 13 (Step S111), and the coin processing device 10 executes. The deformed coin discrimination process is terminated.

  As described above, in the present embodiment, a deformed coin discriminating method and a coin processing device for detecting a deformed coin, an image of a coin is acquired, an outer peripheral portion is cut out based on the acquired image, and further cut out. The defect length is detected from the outer periphery, and it is determined whether the coin is a deformed coin based on the detected defect length, the outer periphery length of the coin, and the ratio.

  Therefore, in the deformed coin discriminating method according to the present invention, it is possible to discriminate whether or not the coin is a deformed coin by image processing for denomination determination without providing a separate sensor. Thereby, in the deformed coin discriminating method according to the present invention, the manufacturing cost for the coin processing device is reduced, and the deformed coin is accurately detected while reducing the coin discriminating portion for performing coin discrimination and the housing of the coin processing device. be able to.

  In the above-described embodiment, the case where the deformed coin is discriminated using the defect length has been described. However, the present invention can be similarly applied to the case where the defect angle is used. For example, the deformed coin discriminating unit 15e calculates the missing angle from the difference between the deflection angles at the start and end of the deformed portion based on the image that has been subjected to polar coordinate conversion into 32 divisions or 64 divisions by the outer periphery cutout unit 15b. And the deformation | transformation coin discrimination | determination part 15e discriminate | determines that it is a deformation | transformation coin when the calculated defect | deletion angle exceeds a predetermined angle.

  Further, although it is determined whether or not the coin is a deformed coin based on the defect angle calculated based on the difference in the declination, the determination is performed based on the number of divisions of the deformed portion of the image that is divided by the outer peripheral cutout unit 15b and converted into polar coordinates. It is good as well. Specifically, the deformed coin discriminating unit 15e discriminates that it is a deformed coin when there are four or more deformed parts in the image that has been subjected to polar coordinate conversion into 64 divisions.

  In the above-described embodiment, an example of the deformed coin discriminating method applied to the coin processing apparatus has been described. However, an apparatus for inspecting the formation accuracy of a circular machined part, for example, a circular part such as a screw thread or a washer. Alternatively, the present invention can be similarly applied to an apparatus for inspecting eccentricity.

  As described above, the deformed coin discriminating method and the coin processing device according to the present invention are useful when detecting a deformed coin with high accuracy while downsizing the coin discriminating portion for performing coin discrimination and the housing of the coin processing device.

DESCRIPTION OF SYMBOLS 10 Coin processing apparatus 11 Imaging part 12 Reject part 13 Storage part 14 Storage part 14a Image information 14b Standard image information 14c Threshold information 15 Control part 15a Image acquisition part 15b Outer peripheral part cutout part 15c Denomination identification part 15d Defect length detection part 15e Deformation Coin discriminating unit 20 Housing 21 Inserting port 22 Supply unit 23 Door 24 Coin feeding unit 25 Conveying unit 26 Conveying path 27 Sorting unit 28a Opening portion 28b Opening portion 28c Opening portion 28d Opening portion 29 Chute 30 Foreign matter discharge chute 31 Reject coin chute

Claims (5)

A deformed coin discriminating method applied to a coin processing device for detecting a deformed coin,
An image acquisition step of acquiring an image of the coin;
A center setting step of setting the center of the coin based on the characteristics of the image acquired by the image acquisition step;
A polar coordinate image obtaining step for obtaining an image obtained by performing polar coordinate conversion on the center of the coin set by the center setting step;
An identification step of identifying the denomination of the coin based on the characteristics of the image acquired by the polar coordinate image acquisition step;
A defect amount detection step of detecting a defect amount of the outer periphery of the coin based on the image acquired by the polar image acquisition step;
Discrimination that determines whether or not the coin is deformed based on the loss amount detected by the loss amount detection step and a threshold value stored in advance for each denomination of the coin identified by the identification step. A method for discriminating deformed coins, comprising: a process. The center setting step includes
Correcting the temporary center to a true center based on the trajectory of the outer peripheral portion detected from an image obtained by performing polar coordinate conversion on the temporary center set based on the characteristics of the image acquired by the image acquiring step; The deformed coin discrimination method according to claim 1. The deficiency detection step includes
The deformed coin discrimination method according to claim 1 or 2 , wherein a defect length of an outer periphery orbit of the coin is used as a defect amount of the outer periphery orbit. The deficiency detection step includes
As missing amount of trajectory of the outer peripheral portion, deformation coin discriminating method according to claim 1 or 2, characterized by using a defect angle indicated by the internal angle of the lost portion of the trajectory of the outer peripheral portion of the coin arc . A coin processing device for detecting a deformed coin,
A coin transport means for transporting the coins sequentially on a transport path and transporting the coins while pressing the coins with a belt-like pressing mechanism;
Image acquisition means for acquiring an image of the coin;
Center setting means for setting the center of the coin based on the characteristics of the image acquired by the image acquisition means;
Polar coordinate image acquisition means for acquiring an image obtained by performing polar coordinate conversion on the center of the coin set by the center setting means;
Identification means for identifying the type of the coin based on the characteristics of the image acquired by the polar coordinate image acquisition means;
Storage means for storing a threshold value for determining that the coin is deformed and determined for each denomination of coins;
A defect amount detection means for detecting a defect amount of the outer periphery of the coin based on the image acquired by the polar coordinate image acquisition means;
The threshold corresponding to the denomination of the coin identified by the identifying means is read from the storage means, and the coin is deformed based on the read threshold and the missing amount detected by the missing amount detecting means. Determining means for determining whether or not,
The identified identified by the identification means result and the coin processing apparatus being characterized in that a separating means for separating the housing section or return opening the coin based on the determination result determined by the determining means.

Images