JP2020064505A - Optical coin identification device, coin processing machine, and coin identification method - Google Patents

Abstract

To provide an optical coin identification device, a coin processing machine, and a coin identification method capable of improving the capability of detecting colors and contamination of coins.SOLUTION: The optical coin identification device for acquiring an image of a coin and executing identification processing, includes a low-angle white light source irradiating a coin surface with light at an irradiation angle of 45 degrees or less, a high-angle white light source irradiating a coin surface with light at an irradiation angle in a range of larger than 45 degrees and 90 degrees or less, an imaging unit acquiring a low-angle image, which includes the whole coin surface illuminated with the low-angle white light source, and a high-angle image, which includes at least a part of the coin surface illuminated with the high-angle white light source, and an identification processing unit for performing identification processing of a coin according to a color component feature quantity of the low-angle image and a color component feature quantity of the high-angle image.SELECTED DRAWING: Figure 7

Description

The present invention relates to an optical coin identification device, a coin processor, and a coin identification method. More specifically, the present invention relates to an optical coin discriminating apparatus, a coin processor, and a coin discriminating method for acquiring an image of a coin and performing a discrimination process.

BACKGROUND ART Conventionally, there is known a technique in which a light source irradiates a coin with light, the reflected light is received to obtain an image, and a coin is identified based on a comparison result between the obtained image and a template. According to this technique, the type of coin (denomination) and damage are detected based on the comparison result. A light source that emits infrared light is known, and the irradiation angle of the light with respect to the coin surface is set relatively small in order to detect the pattern on the coin surface.

In relation to such a technique, in Patent Document 1, a first light emitting source formed of a single color LED different from red, a second light emitting source formed of a red LED, a color light receiving element, and this color light receiving element And a recognition means for recognizing a coin as a subject on the basis of the outer diameter image signal obtained by the first light emitting source and the pattern unevenness image signal obtained by the second light emitting source, and the first light emitting source is the second The coin discriminating device using the image recognition device is characterized in that the coin discriminating device is arranged with an incident angle smaller than that of the light emitting source.

In addition, in Patent Document 2, a low-angle LED and a high-angle LED are provided to discriminate a coin with a raised pattern edge and a coin with an unclear pattern edge such as a gentle portrait. Is disclosed (FIG. 4, [0034] to [0038]).

Patent No. 3090594 Patent No. 5264343

By the way, in order to identify foreign coins, the denomination may not be accurately determined based on not only the pattern on the surface of the coin but also the color of the coin. Further, it has been desired to improve the accuracy of detecting dirty coins. On the other hand, when a light source that irradiates infrared light was used, the color detection accuracy was insufficient, so there was a need to improve the ability to detect the color and stain of coins.

The coin discriminating apparatus of Patent Document 1 obtains an outer diameter image signal from a first light emitting source composed of a single-color LED different from red, and obtains a pattern unevenness image signal from a second light emitting source composed of a red LED. However, it was not an attempt to improve the accuracy of detecting the color of coins. The coin identification device of Patent Document 2 also does not attempt to improve the accuracy of detecting the color of coins.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical coin identification device, a coin processor, and a coin identification method capable of improving the color and stain detection ability of coins. It is a thing.

In order to solve the above-mentioned problems and to achieve the object, the present invention is an optical coin identification device that performs an identification process by acquiring an image of a coin, and is an optical coin at an irradiation angle of 45 degrees or less with respect to a coin surface. A low-angle white light source for illuminating the coin surface, a high-angle white light source for illuminating the coin surface with an irradiation angle in the range of more than 45 degrees and 90 degrees or less, and a coin surface illuminated by the low-angle white light source. A low-angle image including the whole, and an imaging unit that acquires a high-angle image including at least a part of a coin surface illuminated by the high-angle white light source, a color component feature amount of the low-angle image, and the high-angle image An identification processing unit that performs identification processing of coins based on the color component characteristic amount.

Further, the present invention is characterized in that, in the above-mentioned invention, the identification process is at least one of a denomination determination and a stain determination.

Further, the present invention is the above invention, wherein at least one of the low-angle white light source and the high-angle white light source is a combination of a light source emitting red light, a light source emitting green light, and a light source emitting blue light, or white light. It is characterized by comprising a light source that emits.

Further, in the present invention according to the above-mentioned invention, the color component characteristic amount of the low-angle image and the color component characteristic amount of the high-angle image are RGB color space, HSV color space, YCbCr color space or L ^* a ^* b ^* color. The feature amount is a feature amount based on a color component included in the space.

Further, the present invention is, in the above invention, characterized in that a plurality of high-angle images are acquired during a period in which one coin passes and a conveyance unit that conveys coins, and the interval between the acquisition of the plurality of high-angle images is performed. A control unit that controls the imaging interval of the imaging unit so as to obtain a low-angle image;
A selection unit that selects a specific image used for the identification processing from the plurality of high-angle images is further included.

Further, the present invention is a coin processing machine comprising the optical coin identification device.

Further, the present invention provides a low-angle image including the entire coin surface illuminated by the low-angle white light source while the low-angle white light source emits light at an irradiation angle of 45 degrees or less with respect to the coin surface. The first imaging step to acquire, and the high-angle white light source illuminates the coin surface with light at an irradiation angle within a range of more than 45 degrees and 90 degrees or less, while the imaging unit uses the high-angle white light source. A second image capturing step for obtaining a high-angle image including at least a part of the illuminated coin surface, and a coin identification process based on the color component feature amount of the low-angle image and the color component feature amount of the high-angle image. And a step of identifying the coin.

According to the optical coin discriminating apparatus, the coin processor, and the coin discriminating method of the present invention, the ability of detecting the color and stain of the coin can be improved.

3 is a schematic perspective view of the image sensor of Embodiment 1. FIG. It is a plane schematic diagram which shows the conveyance surface of the image sensor of FIG. It is the figure which removed the conveyance path side cover from the image sensor of FIG. 1, and showed the internal structure. It is a cross-sectional schematic diagram of the image sensor of FIG. It is a figure explaining the optical path of the light which a low angle white light source emitted, the solid line shows the optical path of the light with which a coin is irradiated, and the two-dot chain line shows the optical path of the light reflected by the coin. It is a figure explaining the optical path of the light which a high angle white light source emitted, the solid line shows the optical path of the light with which a coin is irradiated, and the two-dot chain line shows the optical path of the light reflected by the coin. 4 is a flowchart showing an example of a flow of coin identification processing by the optical coin identification device of the first embodiment. (A) is an example of a histogram created by the identification processing unit using the RGB color space, (b) is an example of a histogram created by the identification processing unit using the HSV color space, (c) ) Is an example of a histogram created by the identification processing unit using the YCbCr color space, and (d) is an example of a histogram created by the identification processing unit using the L ^* a ^* b ^* color space. . It is a figure explaining the imaging range required when it illuminates a low-angle white light source and a high-angle white light source by turns, and carries out continuous imaging. It is a figure explaining the imaging range required for continuous imaging by illumination of a high angle white light source. It is a graph which showed the wavelength-reflectance characteristic for every metal. 4A and 4B are schematic diagrams for explaining the contrast improvement due to the difference in reflectance, where (a) shows reflection of infrared light and (b) shows reflection of blue light. FIG. 3 is a block diagram illustrating an example of a functional configuration of the optical coin identifying device according to the first embodiment. It is sectional drawing of the coin processor of Embodiment 1. It is a perspective view of the coin processing machine of the first embodiment. It is a top view of the state which pulled out the processing machine main body of the coin processing machine of Embodiment 1 from the processing machine frame. 16A is a sectional view taken along the line AA of FIG. 16, and FIG. 16B is a sectional view taken along the line BB of FIG. It is a cross-sectional schematic diagram of the image sensor of a modification.

(Embodiment 1)
The optical coin identification device of the first embodiment is provided in a coin processing machine used for identifying and counting coins, and acquires an image for identification processing of coins transported in the coin processing machine. In the present specification, the "coin" means coins and all media having a size and shape similar to coins, and not only metal coins but also medals and resin coins (resin coins) and the like. included.

The optical coin identifying device according to the first embodiment includes an image sensor including a low-angle white light source, a high-angle white light source, and an imaging unit. In the optical coin identifying device of the present embodiment, the identification processing unit, the control unit, and the like described later may be mounted on the circuit board in the image sensor, or may be mounted on an external circuit board independent of the image sensor, It may be connected to the image sensor.

First, the structure of the image sensor of the first embodiment will be described with reference to FIGS. FIG. 1 is a schematic perspective view of the image sensor of the first embodiment. FIG. 2 is a schematic plan view showing the transport surface of the image sensor of FIG. FIG. 3 is a diagram showing the internal structure of the image sensor of FIG. 1 with the transport path side cover removed. FIG. 4 is a schematic sectional view of the image sensor of FIG. The arrows in FIGS. 1 and 3 indicate the transport direction of the coin 100 passing through the transport path from the upstream side to the downstream side.

The coin 100 is transported by the transport unit 21 including a transport belt 21a stretched above the transport surface along the transport path and a transport pin 21b fixed to the transport belt 21a at regular intervals, and the image sensor 10 Pass through. The conveyor belt 21a is driven by a drive device including a pulley, a motor, and the like. The cylindrical transport pin 21b contacts the outer edge of the coin 100 and the transport belt 21a moves, whereby the coins 100 are transported one by one on the transport path. The configuration of the transport unit 21 is not limited to the illustrated configuration as long as it can transport the coin 100, and the transport pin 21b may be omitted and only the transport belt 21a may be used, or the shape of the transport pin 21b. And the size may be changed. When the transport pin 21b is omitted, the transport belt 21a moves with the coin 100 while pressing the upper surface of the coin 100. By providing the transport belt 21a, the coin 100 can be slid in contact with the surface of the transport path or the transport guide 28, so that the detection accuracy of the image sensor 10 can be improved. It is preferable that the coin 100 slides on the transport surface in a state where it is biased to the end of the transport path, that is, in a state where the end surface of the coin 100 is in contact with the transport guide 28.

The image sensor 10 includes a low-angle white light source 11 and a high-angle white light source 16 that illuminate the imaging area 22a below a light-transmitting portion 22 having a circular planar shape provided corresponding to the imaging area 22a, and an imaging area. 22a. With the above configuration, it is possible to capture an image while illuminating the coin 100 passing over the translucent portion 22.

Specifically, the low-angle white light source 11, the high-angle white light source 16 and the imaging unit 24 are installed inside a box-shaped housing 26 having an opening at the upper side, and a transport path side cover 27 and The transport guide 28 is attached. The transparent portion 22 is provided at the center of the transport path side cover 27. The material of the light transmitting portion 22 is preferably excellent in strength and transparency, and sapphire glass is preferably used. It is desirable that the size of the light transmitting portion 22 is larger than the diameter of the coin having the largest diameter among the one or more types of coins 100 to be imaged. The transport guide 28 is provided so as to protrude from the upper surface of the transport path cover 27, and functions as a side wall that defines the width of the transport path through which the coin 100 passes. The material of the transport path side cover 27 and the transport guide 28 is not particularly limited, and is made of hard resin, ceramic, metal or the like.

The low-angle white light source 11 is an annular illumination provided in the upper part of the housing 26 and arranged so as to surround the imaging region 22a in a plan view. The low-angle white light source 11 includes a plurality of light emitting elements 12 arranged in an annular shape, and an annular prism (light guide) 13 arranged on the light emitting element 12. The diameter of the annular illumination is made larger than the diameter of the coin having the largest diameter among the one or more types of coins 100 to be imaged. The high-angle white light source 16 is an annular illumination including a plurality of light emitting elements 12 that are provided in the lower part of the housing 26 and are arranged so as to surround the imaging unit 24 in a plan view. Since the high-angle white light source 16 is provided to acquire a high-angle image used for detecting the color of the coin surface, it is sufficient if it can illuminate at least a part of the coin surface, and not the annular illumination. It is also possible to use a spot light source.

The low-angle white light source 11 emits light within an irradiation angle range of 0 to 45 degrees with respect to the coin surface (the upper surface of the transparent portion 22), and the high-angle white light source 16 emits light with respect to the coin surface. Light is emitted within the range of more than 45 degrees and 90 degrees or less. Further, both the low-angle white light source 11 and the high-angle white light source 16 are configured such that the image capturing unit 24 can acquire a color image of the coin 100, and, for example, each of the plurality of light emitting elements 12 emits white light. Alternatively, a combination of a plurality of light emitting elements 12 may emit light in different wavelength ranges to obtain white light. Specific examples of the latter include a combination of a light emitting element that emits red light, a light emitting element that emits green light, and a light emitting element that emits blue light.

A light emitting diode (LED) is suitable as the light emitting element 12 included in the low-angle white light source 11 and the high-angle white light source 16. In the low-angle white light source 11, the light emitted by the light emitting element 12 enters the prism 13. As shown in FIG. 4, the prism 13 has a lower surface (light incident surface) facing the light emitting surface of the light emitting element 12, a reflecting surface that reflects upward light incident from the lower surface in the direction of the imaging region 22a, And a light emitting surface facing the imaging area 22a. In the low-angle white light source 11, a light diffusing film having a function of diffusing light may be provided between the light emitting surface of the prism 13 and the imaging area 22a. In the high-angle white light source 16, a light diffusion film may be provided between the light emitting surface of the light emitting element 12 and the imaging area 22a.

The imaging unit 24 acquires a low-angle image including the entire coin surface illuminated by the low-angle white light source 11 and a high-angle image including at least a part of the coin surface illuminated by the high-angle white light source 16. That is, unlike the emission timing of the low-angle white light source 11 and the emission timing of the high-angle white light source 16, the imaging unit 24 captures images at the emission timing of the low-angle white light source 11 and at the emission timing of the high-angle white light source 16. The imaging timing is controlled so as to capture an image. The image pickup unit 24 has a photoelectric conversion unit 24a in which a CMOS image sensor, a CCD image sensor, and the like are arranged, and receives light reflected by the coin 100 passing through the image pickup region 22a and connects it to the light receiving surface of the photoelectric conversion unit 24a. A lens unit 24b for imaging is included. The image capturing section 24 is preferably arranged in the normal direction of the image capturing area 22a.

5: is a figure explaining the optical path of the light which the low angle white light source 11 emitted, a solid line shows the optical path of the light irradiated to the coin 100, and a dashed-two dotted line shows the optical path of the light reflected by the coin 100. As shown in FIG. ing. As shown in the figure, with respect to the light emitted from the low-angle white light source 11, the component specularly reflected on the coin surface does not enter the imaging unit 24, and the component diffusely reflected on the coin surface enters the imaging unit 24. By illuminating with the low-angle white light source 11, the stain on the coin 100 such as green-blue (turquoise rust) can be detected in a color close to the visual appearance. It is also excellent in the accuracy of detecting the uneven pattern on the coin surface.

FIG. 6 is a diagram for explaining the optical path of the light emitted from the high-angle white light source 16, where the solid line indicates the optical path of the light with which the coin 100 is irradiated, and the alternate long and two short dashes line indicates the optical path of the light reflected by the coin 100. ing. As shown in the figure, with respect to the light emitted from the high-angle white light source 16, the component specularly reflected on the coin surface is incident on the imaging unit 24, and the component diffusely reflected on the coin surface is not incident on the imaging unit 24. Therefore, by illuminating with the high-angle white light source 16, it is possible to detect the color of the coin surface of a new coin that is close to a mirror surface, the presence or absence of metallic luster, and the stain on the coin 100 that is difficult to distinguish visually.

Since the optical coin identification device of the first embodiment including the image sensor 10 includes the identification processing unit that performs the identification process of coins by combining the color component feature amount of the low-angle image and the color component feature amount of the high-angle image. It is possible to improve the color and stain detection capabilities of coins. Hereinafter, an example of a flow of identification processing of the coin 100 by the optical coin identification device of the first embodiment will be described using the flowchart shown in FIG. 7.

When the coin 100 transported by the transport unit 21 plunges into the imaging area 22a, the low-angle white light source 11 emits light and the imaging unit 24 captures an image to obtain a low-angle image (first imaging step S11). Since the low-angle image is used for detecting the uneven pattern on the coin surface, it is assumed to include the entire coin surface.

When the coin 100 transported by the transport unit 21 plunges into the imaging region 22a, the high-angle white light source 16 emits light and the imaging unit 24 captures an image at a timing different from that of the first imaging step S11. An angle image is acquired (second imaging step S21). Since the high-angle image is used for detecting the color of the coin surface, any image including at least a part of the coin surface can be used.

The identification step is performed using the low-angle image acquired in the first imaging step S11 and the high-angle image acquired in the second imaging step S21. The identification step will be described below.

First, the identification processing unit determines a color component extraction area for the acquired low-angle image (step S12). As the color component extraction region, a background portion (black component pixel) where the coin 100 does not exist and a step portion (white component pixel) corresponding to the pattern of the coin 100 from the low angle image obtained by capturing the imaging region 22a. ) And areas other than may be selected. As a result, the base portion (flat portion) of the coin 100 can be extracted as the color component extraction region. The black component and the white component are determined for each pixel based on a predetermined threshold value set using the RGB values of the low angle image.

Next, the identification processing unit calculates the color component feature amount for the color component extraction area in the low angle image (step S13). The method of calculating the color component feature amount is not particularly limited as long as the feature of the color component in the image can be extracted. For example, the value of the color component used in a predetermined color space is taken as the horizontal axis, and all the pixels in the color component extraction area are set. It is possible to create a histogram in which the vertical axis is the number of pixels of the color components included in, and obtain the average value based on this histogram. The color space used for calculating the color component feature amount is not particularly limited, but a known color space such as an RGB color space, an HSV color space, a YCbCr color space, an L ^* a ^* b ^* color space, or the like can be used. 8A is an example of a histogram created by the identification processing unit using the RGB color space, and FIG. 8B is an example of a histogram created by the identification processing unit using the HSV color space. Yes, FIG. 8C is an example of a histogram created by the identification processing unit using the YCbCr color space, and FIG. 8D is an example of the histogram created by the identification processing unit using the L ^* a ^* b ^* color space. It is an example of a histogram created. The RGB color space uses a combination of red, green, and blue color components, the HSV color space uses a combination of hue, saturation, and lightness color components, and the YCbCr color space uses a luminance, blue hue. And saturation, and a combination of red-based hue and saturation are used, and in the L ^* a ^* b ^* color space, a combination of lightness, green to red hue, and blue to yellow hue is used.

In addition, the identification processing unit determines a color component extraction area for the acquired high angle image (step S22). As the color component extraction region, a background portion (black component pixel) where the coin 100 does not exist and a step portion of the coin surface corresponding to the pattern of the coin 100 (black component pixel) from the high-angle image of the imaging region 22a are captured. ) And areas other than may be selected. The black component is determined for each pixel based on a predetermined threshold value set using the RGB values of the high angle image.

Next, the identification processing unit calculates the color component feature amount for the color component extraction area in the high angle image by the same method as in step S13 (step S23).

The identification processing unit compares the obtained color component feature amount of the low-angle image and the obtained color component feature amount of the high-angle image with the template stored in the optical coin identification device to calculate a matching value (step S31). As the matching value, the Euclidean distance between the obtained color component feature amount and the template can be used. The template is prepared corresponding to the identifiable coin type (denomination). When the nth (n is any integer greater than or equal to 1) template n is compared to calculate the nth matching value Dn, the n + 1th template is continuously compared to the n + 1th template. The matching value Dn + 1 of is calculated. If T templates are held, the calculation of the matching value by comparison with the template is repeated until T <n is reached (step S32).

When T <n is reached, the minimum matching value Dmin is obtained from the first matching value D1 to the Tth matching value DT, and the template number Nmin corresponding to the minimum matching value Dmin is specified (step S33). Then, it is determined whether the minimum matching value Dmin is smaller than the preset threshold value 1 (step S34). When the minimum matching value Dmin is smaller than the threshold value 1, it is determined that the denomination is Nmin corresponding to the template number Nmin (step S35), and the flow of the identification process ends. On the other hand, when the minimum matching value Dmin is equal to or greater than the threshold value 1, it is re-determined whether the minimum matching value Dmin is smaller than the preset threshold value 2 (step S36). If the minimum matching value Dmin is smaller than the threshold value 2, it is determined that the stain is found (step S37), and the flow is ended. On the other hand, when the minimum matching value Dmin is equal to or greater than the threshold value 2, it is determined that the coin 100 is rejected (step S38), and the flow is ended.

As described above, by combining the color component feature amount of the low-angle image and the color component feature amount of the high-angle image, the color based on the surface material of the coin 100 can be more accurately grasped, and the coin in the distribution process. It becomes possible to make a denomination determination in which the influence of the change in the color tone of 100 is reduced. Therefore, even coins having similar characteristics in terms of shape (including diameter size, presence / absence of holes), pattern and magnetism can be classified based on the color of the coin surface. Further, by combining the measurement results of the material characteristics detected by the magnetic sensor, it is possible to improve the detection accuracy of the coin or the bi-color coin having the plated surface.

Note that the timing of capturing the low-angle image and the high-angle image may be controlled by using a timing sensor for detecting the arrival of the coin 100, or the imaging region 22a may be provided at a preset imaging interval without providing the timing sensor. The image pickup may be performed continuously. In the former method using the timing sensor, it is necessary to design the arrangement of the conveyor belt 21a and the conveyor pin 21b so as not to interfere with the intrusion detection of the coin 100 by the timing sensor, but in the latter method without the timing sensor. The arrangement of the conveyor belt 21a and the conveyor pin 21b is not restricted by the arrangement of the timing sensor. In order to make a coin processing machine capable of handling a variety of coins inside and outside Japan, it is necessary to increase the range of the diameter of the processable coin 100. However, if the range of the size of the processable coin 100 is increased, It may be difficult to adjust the relationship between the configuration and arrangement of the conveyor belt 21a and the conveyor pin 21b and the arrangement of the timing sensor. Therefore, in the case of a coin processing machine that can handle various domestic and foreign coins, the latter method without a timing sensor is preferably used.

Hereinafter, the imaging timing of the low-angle image and the high-angle image when the method without the timing sensor is used will be described. In the method that does not include the timing sensor, the arrival timing of the coin 100 cannot be detected precisely, so that the conveyance state of the coin 100 is constantly monitored by continuously capturing the image of the imaging region 22a at a preset imaging interval. This transport monitoring may be continuous imaging with illumination of the low-angle white light source 11, continuous imaging with illumination of the high-angle white light source 16, or low-angle white light source 11 and high-angle white light source 16. May be alternately illuminated for continuous imaging, but continuous imaging by illumination of the high-angle white light source 16 is preferable.

The first reason why continuous imaging with illumination of the high-angle white light source 16 is preferable is that the high-angle white light source 16 is used for detecting light reflected on the surface portion (large area) of the coin 100. On the other hand, since the low-angle white light source 11 is used to detect the light reflected by the edge portion (small area) of the coin 100, the reflectance of the high-angle white light source 16 with respect to the illumination is lower. Is larger than the reflectance for the lighting. When the illuminance of the low-angle white light source 11 is increased in order to secure a certain amount of reflected light by the illumination of the low-angle white light source 11, the power consumption and the heat generation amount increase, and the life of the light emitting element 12 shortens. There is a fear.

The second reason why continuous imaging by illumination of the high-angle white light source 16 is preferable is that the sensor can be downsized because the imaging range can be reduced as described below. When an expensive sapphire glass is used for the light transmitting portion 22 in order to make the light transmitting portion 22 excellent in durability, if the area of the light transmitting portion 22 can be reduced by downsizing the sensor, the manufacturing cost is increased. It can be reduced.

FIG. 9 is a diagram for explaining an imaging range required in the case where the low-angle white light source 11 and the high-angle white light source 16 are alternately illuminated for continuous imaging, and FIG. It is a figure explaining the imaging range required for imaging. Since the low angle image 111 including the entire coin surface is used in the identification processing, it is necessary to reliably acquire the low angle image 111 including the entire coin surface. In the method without the timing sensor, since the arrival timing of the coin 100 cannot be strictly detected, it is possible to capture two or more low-angle images 111 within the time required for one coin 100 to pass through the imaging area 22a. , And controls the imaging interval of the low-angle image 111. As a result, a margin M is set in the imaging range A1 in FIG. 9 so that the low-angle image 111 including the entire two or more coin surfaces can be reliably acquired, and the imaging range A1 becomes large. On the other hand, since the high angle image 116 is mainly for detecting the color of the coin 100, it can be used for the identification process as long as it includes at least a part of the coin surface. If the low-angle image 111 is captured after detecting the arrival timing of the coin 100 by capturing the high-angle image 116, the low-angle image 111 including the entire coin surface can be reliably acquired without providing a margin. The imaging range A2 in FIG. 10 can be made smaller than the imaging range A1 in FIG.

Further, the low-angle image 111 can detect the stain of the coin 100 such as patina with a color close to the appearance, and is superior in detection accuracy of the uneven pattern on the coin surface as compared with the high-angle image 116. There is. However, since foreign coins may be provided with a pattern having small unevenness, such as a portrait, it is difficult to make a difference in reflected light intensity between the flat portion and the uneven portion of the surface of the coin 100, and a high-contrast image can be obtained. May not be On the other hand, if the low-angle image 111 is imaged using a short wavelength region in which the reflectance of the base material of the coin surface is relatively small, the contrast can be improved. FIG. 11 is a graph showing wavelength-reflectance characteristics for each metal. As shown in FIG. 11, the reflectance in the short wavelength region tends to be lower than that in the infrared region. Particularly, for copper and gold, the reflectance for blue light (wavelength about 450 nm) is infrared light. It is about half of the reflectance (wavelength over 800 nm). 12A and 12B are schematic diagrams for explaining the contrast improvement due to the reflectance difference. FIG. 12A shows reflection of infrared light and FIG. 12B shows reflection of blue light. . In illumination with a low-angle light source, diffuse reflection occurs at a flat portion and regular reflection occurs at an uneven portion. As shown in FIG. 12A, when the infrared light source 12IR is used, since the reflectance of the base material of the coin surface is high, the difference between the intensity of diffuse reflected light and the intensity of specular reflected light is small. On the other hand, as shown in FIG. 12B, when the blue light source 12B is used, the intensity of the diffuse reflected light also decreases as the reflectance of the base material of the coin surface decreases, so that the diffuse reflected light The difference between the intensity and the intensity of the specular reflection light becomes large, and the contrast is improved. Therefore, in order to improve the detection accuracy of the uneven pattern on the coin surface, as the low-angle image 111, in addition to the color image used for calculating the color component feature amount, a coin image captured only with blue light or a blue image from the color image is used. You may use the coin image created by extracting the components. Moreover, you may image with the light of a wavelength shorter than blue light.

Next, an example of the functional configuration of the optical coin identifying device according to the first embodiment will be described with reference to the block diagram shown in FIG.

The control unit 30 includes a conveyance control unit 31, an imaging control unit 33, and an image detection unit 34. The transport control unit 31 controls the transport of the coin 100 by the transport unit 21 including the transport belt 21a and the like. The image pickup control unit 33 controls the light emission timings of the low-angle white light source 11 and the high-angle white light source 16 and the image pickup timing of the image pickup unit 24 to synchronize them. The image detection unit 34 creates the low-angle image 111 and the high-angle image 116 of the coin 100 based on the output of the imaging unit 24. Coins such as an amplification circuit, a filter circuit, an AD conversion circuit, and a drive circuit are appropriately provided between the control unit 30 and sensor constituent members such as the low-angle white light source 11, the high-angle white light source 16, the imaging unit 24, and the like. A circuit common in the field of processing machines may be interposed.

The storage unit 50 is used to store various data necessary for the processing performed by the optical coin discriminating apparatus, and specifically, the threshold value used for determining the black component and the white component and the maximum matching value Dmax. The coin information 51 related to the processing target coin 100 such as various threshold values 56 such as a threshold value used for the comparison, the template 57 used for the comparison with the color component feature amount, and the like is stored in advance in association with the processing of the coin 100. The angle image 111 and the high angle image 116 are stored.

When a plurality of low-angle images 111 and / or a plurality of high-angle images 116 are picked up during a period in which one coin 100 passes, the selecting unit 60 selects from the images by the identification processing unit 70. Select a specific image to be used in the identification process of. That is, the selection unit 60 is provided when the transportation state of the coin 100 is constantly monitored by continuously capturing the image of the image capturing area 22a at a preset image capturing interval without providing the timing sensor.

The identification processing unit 70 is used to perform coin identification processing, and performs the type of coin 100 (determination of denomination), correctness determination (contamination determination), authenticity determination, and the like. At least a part of the identification processing by the identification processing unit 70 is performed by a method of using the color component feature amount of the low-angle image 111 and the color component feature amount of the high-angle image 116 in combination, and at least one of the denomination determination and the stain determination. Is preferably performed by a method in which the color component characteristic amount of the low angle image 111 and the color component characteristic amount of the high angle image 116 are used together. For example, according to the flow shown in FIG. 7, both the denomination determination and the stain determination can be performed by using the color component feature amount of the low angle image 111 and the color component feature amount of the high angle image 116 together.

The physical configurations of the control unit 30, the selection unit 60, and the identification processing unit 70 include, for example, a software program for realizing various processes, a CPU (central processing unit) that executes the software program, and a control by the CPU. Examples of the hardware include various hardware and logic devices such as FPGA (Field Programmable Gate Array). The storage unit 50, a memory such as a RAM and ROM separately provided, a hard disk, and the like are used to store software programs and data necessary for the operation of each unit.

Examples of the physical configuration of the storage unit 50 include a storage device such as a volatile or non-volatile memory or a hard disk.

Hereinafter, a case where images are selected by the selection unit 60 will be described in detail based on an example in which continuous imaging is performed by illumination of the high-angle white light source 16.

In the continuous imaging by the illumination of the high-angle white light source 16, the imaging control unit 33 sets the light-emission timing of the high-angle white light source 16 and the light-emission timing of the high-angle white light source 16 so that the imaging interval is shorter than the time when one coin 100 passes through the imaging area 22a. This is performed by controlling the image pickup timing of the image pickup unit 24. The control of the imaging interval is performed according to, for example, the diameter of the coin 100 to be identified, the transport speed of the coin 100 adjusted by the transport unit 21, and the size of the imaging region 22a. Imaging of the coin 100 is preferably performed at an imaging interval capable of capturing two or more images of the coin having the largest diameter among the coins 100 to be imaged. This ensures that at least two high-angle images can be acquired, and thus the image quality of the selected image for identification processing can be ensured. Further, the image detection unit 34 acquires a plurality of high-angle images 116 during the period when one coin 100 passes.

Then, when the arrival of the coin 100 is detected based on the high-angle image 116 and the like, a plurality of high-angle images are acquired during a period in which one coin 100 passes, and a plurality of high-angle images are acquired. The imaging interval of the imaging unit is controlled so that a low-angle image is acquired in the interval.

In the case where another sensor different from the image sensor 10 is provided at a position on the upstream side of the image sensor 10 in the transport path, the imaging control unit 33 causes the image pickup control unit 33 to detect the arrival of the coin 100 after the other sensor. The control of shortening the imaging interval of the imaging unit 24 may be performed during the predetermined period. As a result, it is possible to reduce the acquisition of images that do not include the coin 100 and simplify the processing.

The type of another sensor is not particularly limited, but a magnetic sensor can be used. Examples of the magnetic sensor include a sensor including a magnetic detection element such as a magnetoresistive element and a Hall element (Hall IC). When the coin 100 passes over the magnetic detection element, its output signal changes according to the magnetic amount of the coin 100. If a magnetic sensor is used, the arrival of the magnetic coin 100 can be detected. The magnetic sensor is provided to acquire the magnetic information of the coin 100 used for the identification process, and does not have only the function of detecting the arrival of the coin 100 like the passage detection sensor. When a passage detection sensor including a photo sensor or the like is attached to the magnetic sensor, the passage detection sensor may be used.

When the imaging interval of the imaging unit 24 is temporarily shortened by using another sensor, the shortened imaging interval can capture two or more images of the coin having the largest diameter among the coins 100 to be imaged. The imaging interval is preferable.

When the imaging interval of the imaging unit 24 is temporarily shortened by using another sensor, the imaging intervals before and after the shortening are at least a part of the smallest-sized coin (small-sized coin) in the coin 100 to be imaged. It is preferable that the imaging interval is such that the image can be captured. That is, the imaging control unit 33 images at least a part of the small-sized coin before another sensor detects the arrival of the coin 100 and after a lapse of a predetermined period after the other sensor detects the arrival of the coin 100. It is preferable to perform control so that the imaging interval is possible. Accordingly, it is possible to prevent the occurrence of the coin 100 that is not imaged by the imaging unit 24 when another sensor does not detect the coin 100 while reducing the acquisition of the image that does not include the coin 100.

An example of how to obtain the imaging interval capable of imaging at least a part of a small coin is shown below.
<Condition>
-Imaging area 22a of the imaging unit 24: 45 mmΦ
・ Coin 100 transfer speed: 2000 mm / sec
・ Small coin diameter: 14mmΦ
<Calculation formula>
(45 + 14) /2000=29.5 (msec)
Therefore, under the above conditions, if images are taken at intervals of 29.5 msec or less, at least a part of the small-sized coin can be taken.

The selection unit 60 selects a specific image as an image for identification processing from the acquired plurality of high angle images 116. The selection condition used by the selection unit 60 is not particularly limited, but the selection unit 60 selects the center of the coin 100 that is imaged as the image for identification processing from the plurality of high-angle images 116 and is closest to the center of the imaging region 22a. It is preferable to select an image. In addition, a specific part of the coin 100 is set in advance as a reference point, and an image in which the center of the coin 100 is closest to the center of the imaging region 22a is used as an image for identification processing based on the position of the reference point of the coin 100 that is imaged. It is preferable to select. As the reference point, one that can specify the position or state of the coin 100 can be used, and for example, an arbitrary position such as the center point of the coin 100 or an end (edge) may be used. Is preferably used.

The optical coin identifying device according to the first embodiment is provided in a coin processing machine used for identifying and counting coins. Here, the optical coin identification device may be a unit component configured to be detachable from the coin processing machine, or may be a part of the coin processing machine integrally configured with the coin processing machine.

Hereinafter, an example of the configuration of the coin processing machine in which the optical coin identifying device according to the first embodiment is incorporated will be described with reference to FIGS. FIG. 14 is a cross-sectional view of the coin processing machine of the first embodiment, FIG. 15 is a perspective view of the coin processing machine of the first embodiment, and FIG. 16 is a processing machine main body of the coin processing machine of the first embodiment. 17A is a plan view in a state of being pulled out from FIG. 17, FIG. 17A is a sectional view taken along line AA of FIG. 16, and FIG. 17B is a sectional view taken along line BB of FIG.

The processing machine main body 512 is mounted in the processing machine frame 511 through the front opening of the processing machine frame 511, and the processing machines are provided by the guide rail mechanisms 513 on both sides of the processing machine frame 511. The main body 512 is supported so as to be able to be drawn out from the processing machine frame 511.

In the front part 512a of the processor body 512, a coin receiving port 525 is formed on the right side of the upper surface at an upper position on the front side, and an operating part 526 is formed on the left side of the upper surface. A saucer-shaped coin payout outlet 527 is formed on the right side, a detachable storage box 528 is detachably provided on the right side, that is, it can be pulled out forward, and a power switch 529 is provided at the center.

The coin receiving port 525 receives coins inserted into the processor body 512, and has a bottom opening. The coin payout exit 527 is for paying out coins from the inside of the processor main body 512.

Further, the processor main body 512 has a denomination storing section 541 for storing coins classified by denomination, and the coins inserted into the coin receiving port 525 are fed one by one and sorted into the denomination storing section 541. Deposit mechanism, pays out necessary coins from the coin storing unit 541 according to a withdrawal command and pays out to the coin payout outlet 527, pays out coins from the coin storing unit 541 according to a coin recovery command, and pays coins It has a recovery mechanism for recovering to the outlet 527.

A flat belt 542 that forms the bottom surface of the coin receiving port 525 is arranged below the coin receiving port 525 along the front-rear direction, and the flat belt 542 is tilted upward in the rearward rewinding direction to drive the flat belt 542 to rotate. Thus, the coins on the flat belt 542 are fed backward and conveyed. Above the rear end side of the flat belt 542, the reverse rotation that is reversely driven in the direction opposite to the rotation direction of the upper surface of the flat belt 542 so that the coins placed on the flat belt 542 pass through one by one in the thickness direction. A roller 543 is provided.

The rear end of the flat belt 542 is connected to the entrance of the coin passage 544. The coin passage 544 has a coin identification passage portion 545 arranged along the right side of the processor main body 512 and a denomination-based coin sorting passage portion 546 arranged along the rear side of the processor main body 512. It is formed in a substantially L shape as a whole. The coin passage 544 is formed on the passage plate 547 forming the bottom of the passage and between the guide side plates 548 and 549 on both sides forming both sides of the passage, and extends along the upper side of the coin identification passage portion 545 and the coin classification passage portion 546. The coins are transported by the transport belts 550, 551 and 552 that are stretched respectively. The coins conveyed by the conveyor belts 550, 551, and 552 are faster than the coins retracted by the flat belt 542, and the coins accommodated in the coin passage 544 are conveyed one by one at a front and rear interval. To be done.

In the coin identification passage portion 545, a guide side plate 548 on one side is formed as a reference edge 548a that projects toward the passage center side and is conveyed while the coin is in contact therewith. The magnetic sensor 553 and the image sensor correspond to the reference edge 548a. 10 and coin sorting section 554 are arranged in order. Note that the magnetic sensor 553 is located upstream of the image sensor 10 in normal transport, but the coin processing machine can switch the transport direction in both directions, and in reverse transport, the image sensor 10 is located upstream of the magnetic sensor 553. Will be located. The magnetic sensor 553 and the image sensor 10 identify the denomination of coins, whether the coins are right or wrong, and whether the coins are true or false, based on the material, diameter, existence of holes, and the like of the coins. The coin sorting unit 554 forcibly drops and sorts coins, such as spoiled coins, counterfeit coins, and overflow coins when the coin-type storing unit 541 is full, and sorts them. A sorting hole 555 is formed in the shutter hole 555, and a shutter 556 that is moved back and forth in and out of the passage in the passage width direction by the solenoid SD1 is disposed in the sorting hole 555. A chute 557 is attached to the lower side of the sorting hole 555 to guide coins dropped from the sorting hole 555 to the removable storage box 528. Then, normally, when the shutter 556 has entered the passage and coins are allowed to pass through, and when a damaged coin, a counterfeit coin, and an overflow coin are identified, the shutter 556 is retracted to the outside of the passage, and the coin It is dropped from the sorting hole 555 and stored in the detachable storage box 528 below. As described above, the coin processing machine has the reject (discharging) unit that removes the coin (damaged coin) that is determined to be dirty by the identification processing unit.

The coin-type coin sorting passage portion 546 is configured such that the guide side plate 549 on the other side projects toward the center of the passage to form a reference edge 549a, and along this reference edge 549a, small coins on the upstream side to large diameter coins on the downstream side are arranged in order. A selection hole 558 for selecting the diameter according to the type is formed. The coins dropped from the respective sorting holes 558 are sorted and stored according to the denomination in the denomination storing section 541 below.

The denomination-specific storage unit 541 is partitioned by the storage unit frame 581 in the left-right direction of the processor main body 512 for each denomination, and an opening 583 that is opened and closed by a lid 582 is formed on the storage unit frame 581. ing. The bottom surface of each denomination-specific storage portion 541 is configured by a flat belt 584, and the flat belt 584 is stretched in an inclined shape so as to rise in the forward payout direction and is rotationally driven in the payout direction.

Above the front end side of the flat belt 584, a reverse roller 585 that is reversely driven in a direction opposite to the rotation direction of the upper surface of the flat belt 584 and regulates the coins on the flat belt 584 to pass one by one in the thickness direction. Is provided. A stopper mechanism 586 for stopping the coins conveyed by the flat belt 584 is disposed in front of the reverse rotation roller 585. The stopper mechanism 586 advances and retracts the stopper 587 and the stopper 587 with respect to the coin conveyance area. It has a solenoid SD3 for making it. On the front side of the stopper mechanism 586, a counting sensor 588 composed of a photo sensor that detects coins discharged through the stopper mechanism 586 is provided.

A chute 589 for guiding the coins discharged from each coin storing unit 541 to the coin payout outlet 527 is arranged at the front side position where the coins are discharged from each coin storing unit 541.

In the usage state of the coin handling machine, the coin handling machine is placed on the upper surface of the cash register, and the cash register 607 is placed on the coin handling machine for use.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The configurations of the above-described embodiments may be appropriately deleted, changed, or combined without departing from the scope of the present invention.

(Modification)
Although the annular illumination similar to the low-angle white light source is used as the high-angle white light source in the first embodiment, the high-angle white light source is a coaxial epi-illumination equipped with a beam splitter as in the modification shown in FIG. You may use. FIG. 18 is a schematic sectional view of an image sensor of a modified example. The solid line in the figure shows the optical path of the light emitted from the surface emitting light source (not shown) of the high-angle white light source to the coin 100, and the chain double-dashed line shows the optical path of the light reflected by the coin 100. .

The high angle white light source of the modified example has a configuration in which the light of the surface emitting light source is reflected by the beam splitter 19, and illuminates the entire surface of the coin 100 from the normal direction below the light transmitting portion 22. The surface emitting light source is not particularly limited, but for example, a light emitting substrate having a plurality of light emitting elements (LEDs) mounted on the surface is used. The beam splitter 19 reflects the light incident from the surface emitting light source toward the imaging area 22a and transmits the light reflected by the surface of the coin 100 passing through the imaging area 22a. The light transmitted through the beam splitter 19 is received by the imaging unit 24. The beam splitter 19 has a reflecting surface that is oriented obliquely to the traveling direction of the light emitted from the surface-emitting light source and the transport surface of the coin 100. For example, as shown in FIG. A reflecting surface is provided which is inclined at 45 ° with respect to the transport surface. The beam splitter 19 may have any function of reflecting and transmitting incident light, and the ratio of transmitted light to reflected light is not particularly limited, but the ratio of transmitted light to reflected light is 1 :. A half mirror showing a characteristic of 1 is preferably used.

As described above, the optical coin discriminating apparatus and the coin discriminating method according to the present invention are capable of improving the color and stain detection ability of coins, and thus are a technique useful for proper selection of coins in a coin processor. .

10: image sensor 11: low angle white light source 12: light emitting element 12B: blue light source 12IR: infrared light source 13: prism (light guide)
16: High-angle white light source 19: Beam splitter 21: Conveying part 21a: Conveying belt 21b: Conveying pin 22: Light transmitting part 22a: Imaging area 24: Imaging part 24a: Photoelectric converting part 24b: Lens unit 26: Housing 27: Transport path side cover 28: transport guide 30: control unit 31: transport control unit 33: imaging control unit 34: image detection unit 50: storage unit 51: coin information 56: threshold value 57: template 60: selection unit 70: identification processing unit 100 : Coin 111: Low angle image 116: High angle image 511: Processor frame 512: Processor main body 512a: Front part 513: Guide rail mechanism 525: Coin receiving port 526: Operation part 527: Coin paying outlet 528: Detaching storage Box 529: Power switch 541: Storage section 542 by denomination: Flat belt 543: Reverse rotation roller 544: Coin passage 545: Hard Identification passage portion 546: Coin sorting passage according to denomination 547: Passage plates 548, 549: Guide side plates 548a, 549a: Reference edges 550, 551, 552: Conveyor belt 553: Magnetic sensor 554: Coin sorting portion 555, 558: Sorting hole 556: Shutter 557: Shoot 581: Storage part frame 582: Lid 583: Opening 584: Flat belt 585: Reverse rotation roller 586: Stopper mechanism 587: Stopper 588: Count sensor 589: Shoot 607: Cash register M: Margin SD1, SD3: Solenoid

Claims (7)

An optical coin identification device that acquires an image of a coin and performs identification processing,
A low-angle white light source that illuminates the coin surface with an illumination angle of 45 degrees or less,
A high-angle white light source that emits light at an irradiation angle within a range of more than 45 degrees and 90 degrees or less with respect to a coin surface,
An imaging unit that acquires a low-angle image including the entire coin surface illuminated by the low-angle white light source, and a high-angle image including at least a part of the coin surface illuminated by the high-angle white light source,
An optical coin identification device, comprising: an identification processing unit that performs identification processing of coins based on the color component feature amount of the low-angle image and the color component feature amount of the high-angle image. The optical coin identification device according to claim 1, wherein the identification process is at least one of a denomination determination and a stain determination. At least one of the low-angle white light source and the high-angle white light source is configured by a combination of a light source that emits red light, a light source that emits green light, and a light source that emits blue light, or a light source that emits white light. The optical coin identification device according to claim 1 or 2. The color component feature amount of the low-angle image and the color component feature amount of the high-angle image are feature amounts based on color components included in the RGB color space, HSV color space, YCbCr color space or L ^* a ^* b ^* color space. The optical coin discriminating apparatus according to any one of claims 1 to 3, wherein A transport unit for transporting coins,
The imaging interval of the imaging unit is controlled so that a plurality of high-angle images are acquired during the passage of one coin, and the low-angle images are acquired between the acquisition of the plurality of high-angle images. A control unit,
A selection unit that selects a specific image to be used for the identification processing from the plurality of high-angle images,
The optical coin discriminating device according to claim 1, further comprising: A coin processing machine comprising the optical coin identification device according to any one of claims 1 to 5. A first imaging in which the low-angle white light source irradiates the coin surface with light at an irradiation angle of 45 degrees or less, and the imaging unit acquires a low-angle image including the entire coin surface illuminated by the low-angle white light source. Steps,
At least a part of the coin surface illuminated by the high-angle white light source while the high-angle white light source emits light at an irradiation angle within a range of more than 45 degrees and 90 degrees or less with respect to the coin surface. A second imaging step of acquiring a high-angle image including
A coin discriminating method comprising: a discriminating step of discriminating a coin based on the color component characteristic amount of the low-angle image and the color component characteristic amount of the high-angle image.

Images