JP2018124858A - Image sampling apparatus, coin-shaped medium processor, and image sampling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image sampling apparatus which can sample a high-contrast coin-shaped medium image with a simple and compact mechanism suitable for high-speed processing.SOLUTION: An image sampling apparatus for sampling an identification image of a coin-shaped medium includes: a light source having a plurality of light-emitting units and irradiating a surface of the coin-shaped medium with light emitted by the light-emitting units; an imaging element which images the light reflected on the surface of the coin-shaped medium, to capture the coin-shaped medium; and a control unit which controls the light-emitting units to emit light at different light-emitting periods in one exposure period with respect to the imaging element.SELECTED DRAWING: Figure 5

Description

The present invention relates to an image capturing device, a coin-shaped medium processing machine, and an image capturing method. More specifically, the present invention relates to an image collection device that collects an image for identification processing of a coin-shaped medium, a coin-shaped medium processing machine, and an image collection method.

2. Description of the Related Art Conventionally, in order to perform a coin identifying process, an image capturing device having a configuration in which a coin is irradiated with light and its reflected light is imaged is used.

For example, Patent Document 1 discloses that Low angle LEDs and High angle LEDs having different incident angles are arranged in a circular shape, and light is emitted from these LEDs to a coin.

Further, Patent Document 2 discloses that a light irradiating unit is provided which is configured by light emitting elements arranged in an annular shape so as to surround a coin and irradiates light on the surface of the coin. This light irradiating means is divided into three equal areas, and the coin image detecting device of Patent Document 2 is an image of an entire coin obtained in a state where all areas are irradiated with light all at once, and 3 Light is applied to coins at different irradiation timings in one region, and coins are identified using image data of one shadow of the entire coin obtained by combining images detected for each irradiation timing. It was.

Patent No. 5264343 Japanese Patent No. 4615397

On the surface of overseas coins, there are cases where uneven patterns with gentle steps are carved like portraits. Such a pattern tends to make the shadow thin even when light is irradiated on the coin, and it has been difficult to obtain a clear coin image by a conventional image capturing device. Moreover, since the coin image obtained by the image sampling device is used not only for identifying the type of coin but also for checking the scratch, pattern and color of the coin surface, it is required to improve the clarity of the coin image. It was.

On the other hand, Patent Document 1 discloses that only a high-angle LED or both LEDs emit light to obtain an image that reflects a pattern with an unclear edge (see FIG. 4, [0038]). However, in the configuration in which a plurality of light sources having different incident angles are arranged, there are problems that the sensor size is increased in order to ensure a large incident angle, and that the number of parts is increased and the configuration of the apparatus is complicated.

Moreover, since the coin image detection apparatus of Patent Document 2 collects a plurality of images, the processing time of the acquired image becomes long, and is not suitable for high-speed processing of an image corresponding to high-speed conveyance of coins.

The present invention has been made in view of the above-described present situation, and an image capturing device, a coin-shaped medium processing machine, and an image capturing device capable of capturing a high-contrast coin-shaped medium image by a simple mechanism suitable for downsizing and high-speed processing. It is intended to provide a method.

In order to solve the above-described problems and achieve the object, the present invention is an image collection device for collecting an image for identification processing of a coin-shaped medium, which has a plurality of light-emitting units and has the plurality of light-emitting units. A light source for irradiating the surface of the coin-shaped medium with light emitted from the unit, an image sensor for imaging the light reflected by the surface of the coin-shaped medium, and imaging the coin-shaped medium, and a single unit for the image sensor. And a control unit that performs control to vary the timing of each light emitting period of the plurality of light emitting units within an exposure period.

Further, the present invention is characterized in that, in the above invention, the light source irradiates light from a plurality of oblique directions to the surface of the coin-like medium within a single exposure period for the image sensor.

Further, according to the present invention, in the above invention, the plurality of light emitting units are arranged around an imaging region where the coin-like medium is located at the time of imaging in plan view, and face each other through the imaging region. It includes at least a pair of light emitting portions.

Moreover, the present invention is characterized in that, in the above invention, the plurality of light emitting portions are arranged in an annular shape.

Moreover, the present invention is characterized in that, in the above-mentioned invention, the light source irradiates light from a normal direction to each of a plurality of partitioned regions within a single exposure period for the image sensor.

Moreover, the present invention is characterized in that, in the above invention, the plurality of light emitting portions are arranged in a matrix.

Moreover, the present invention is characterized in that, in the above-mentioned invention, a cylindrical optical axis correction grating for dividing light emitted from each of the plurality of light emitting sections is further provided.

In the invention described above, the invention further includes a beam splitter that reflects part of light emitted from each of the plurality of light emitting units toward the surface of the coin-like medium.

Moreover, this invention is a coin-shaped medium processing machine provided with the said image collection device.

In addition, the present invention is an image collection method for collecting an image for identification processing of a coin-shaped medium, and a control unit differs from each of a plurality of light emitting units constituting a light source within a single exposure period for an image sensor. Based on light source control that emits light at timing and irradiates the surface of the coin-shaped medium, and an image of the coin-shaped medium based on the reflected light of the surface of the coin-shaped medium that the image sensor receives during the single exposure period. And collecting images to be collected.

According to the image collection device, coin-like medium processing machine, and image collection method of the present invention, a high-contrast coin-like medium image can be collected by a simple mechanism suitable for downsizing and high-speed processing.

3 is a schematic perspective view of a sensor unit including an image sensor of the image capturing device according to Embodiment 1. FIG. It is a plane schematic diagram which shows the conveyance surface of the sensor unit of FIG. It is the figure which removed the conveyance path side cover from the image sensor of FIG. 2, and showed the internal structure. It is a cross-sectional schematic diagram of the image sensor of FIG. It is a figure which shows the light emission condition of light emission array 23A, 23B, 23C, 23D in time AD within the single exposure period with respect to the image pick-up element 24. FIG. It is a wave form diagram which shows the relationship between the single exposure period with respect to the image pick-up element 24 in the illumination method of Embodiment 1, and the light emission period of four light emission array 23A, 23B, 23C, 23D. (A) is a figure which shows a mode when the light emission array 23A illuminates the coin 100, (b) is a graph which shows the brightness | luminance when the site | part enclosed with the dotted line in (a) is imaged. (A) is a figure which shows a mode when the light emission array 23C illuminates the coin 100, (b) is a graph which shows the brightness | luminance when the site | part enclosed with the dotted line in (a) is imaged. It is a graph which shows the contrast in the level | step difference surface which faces the light emission array 23C of the convex part 101 when the illumination method of Embodiment 1 is used. It is a wave form diagram which shows the relationship between the exposure period with respect to the image pick-up element in the conventional illumination method, and the light emission period of a light emission part. It is a conceptual diagram which shows a mode when the light emission part of annular illumination illuminates the surface of a coin with the conventional illumination method. It is a graph which shows the contrast in the level | step difference surface facing the light emission array 23C of the convex part 101 at the time of using the conventional illumination method. FIG. 5 is a schematic diagram illustrating a configuration of an image sensor of an image capturing device according to a second embodiment. FIG. 6 is a schematic plan view illustrating the shape of an optical axis correction grating provided in an image sensor of an image capturing device according to Embodiment 2. It is a plane schematic diagram which shows the light emission surface of the light source which showed the light emission order of the light emission part in the illumination method of Embodiment 2. FIG. It is a wave form diagram which shows the relationship between the exposure period with respect to the image pick-up element in the illumination method of Embodiment 2, and the light emission period of a some light emission part.

Hereinafter, an embodiment of an image capturing device of the present invention will be described with reference to the drawings. The image sampling apparatus according to the present embodiment is provided in a coin-like medium processing machine used for identifying and counting coin-like media, and displays an image for identifying processing of a coin-like medium conveyed in the coin-like medium processing machine. Collect. The image collecting device may be a unit part configured to be detachable from the coin-shaped medium processing machine, or may be a part of a coin-shaped medium processing machine configured inseparably from the coin-shaped medium processing machine. .

Further, the image capturing device according to the present embodiment is used for capturing images of coins, but can be used for capturing images of media having a size similar to coins other than coins. Images of coin-like media such as resin coins and medals can be collected. That is, in the present specification, the “coin-like medium” means a coin and any medium having a shape similar to the coin, and usually does not include banknotes. In a coin-like medium processing machine, when a coin-like medium (foreign matter) other than coins is thrown into the slot, it is possible to discriminate between coins and foreign matter, accept coins, and reject (discharge) foreign matters. It is.

(Embodiment 1)
First, a sensor unit including an image sensor 2 constituting a part of the image capturing device according to the present embodiment will be described with reference to FIGS. The sensor unit includes a magnetic detection sensor 1, an image sensor 2, a damage detection sensor (optical detection sensor) 3, a phosphorescence detection sensor 4, and a fluorescence detection sensor 5 in order from the upstream side to the downstream side of the transport path. A plurality of sensors are integrated. The arrows in FIGS. 1 and 3 indicate the conveyance direction of the coin 100 passing through the conveyance path.

The image capturing device according to the present embodiment collects an image for identification processing using the image sensor 2, but as shown in the figure, other various sensors may be provided around the image sensor 2. Good. Since individual sensors are arranged corresponding to the respective detection elements of the coin 100, highly accurate detection is possible, and the identification capability (identification accuracy) of the coin-shaped medium processing machine is improved. In addition, the denomination of various coins 100 can be determined, and a sensor unit that can be applied globally can be obtained. Furthermore, by integrating and integrating a plurality of sensors, cost reduction and space saving can be achieved. About sensors other than the image sensor 2, since a general sensor is applicable in the field | area of a coin-like medium processing machine, detailed description is abbreviate | omitted.

In the present embodiment, as shown in FIG. 2, as the transport unit 21 that transports the coin 100, a transport belt 21a stretched above the transport surface along the transport path, and fixed to the transport belt 21a at regular intervals. A transport pin 21b is provided. The conveyor belt 21a is driven by a driving device including a pulley, a motor, and the like. The columnar conveyance pins 21b come into contact with the outer edge of the coin 100, and the conveyance belt 21a moves, so that the coins 100 are conveyed on the conveyance path one by one at intervals. The configuration of the transport unit 21 is not limited to the illustrated configuration as long as the coin 100 can be transported. The transport pin 21b may be omitted and only the transport belt 21a may be used, or the shape of the transport pin 21b may be omitted. The size may be changed. When the conveyance pin 21 b is omitted, the conveyance belt 21 a moves with the coin 100 while pressing the upper surface of the coin 100. By providing the conveyor belt 21a, the coin 100 can be slid while being in contact with the surface of the conveyor path or the conveyor guide 28, so that the accuracy of detection by a sensor such as the image sensor 2 can be improved. Moreover, since the position during conveyance of the coin 100 can be regulated also by providing the conveyance pin 21b, the accuracy of detection by a sensor such as the image sensor 2 can be improved. It is preferable that the coin 100 slides on the conveyance surface in a state where it is shifted to the end of the conveyance path, that is, in a state where the end surface of the coin 100 is in contact with the conveyance guide 28.

As shown in FIGS. 2 to 4, the image sensor 2 includes a light source 23 that illuminates the imaging region 22 a below the transparent portion 22 having a circular planar shape provided corresponding to the imaging region 22 a, and the imaging region 22 a. And an image pickup device 24 for picking up images. FIG. 3 is a view showing a state where the conveyance path side cover 27 is removed from the image sensor 2 shown in FIG. 2, and shows the internal structure of the image sensor 2. With the above configuration, it is possible to take an image while illuminating the coin 100 passing over the transparent portion 22.

Specifically, the light source 23 and the image sensor 24 are installed inside a box-shaped housing 26 that opens upward, and a transport path side cover 27 and a transport guide 28 are attached to the top of the housing 26. The transparent portion 22 is provided in the center of the transport path side cover 27. The material of the transparent portion 22 is preferably excellent in strength and transparency, and sapphire glass is preferably used. The dimension of the transparent portion 22 is desirably larger than the coin having the largest diameter among the coins 100 to be identified. The conveyance guide 28 is provided so as to protrude from the upper surface of the conveyance path side cover 27, and functions as a side wall that defines the width of the conveyance path through which the coin 100 passes. The material of the conveyance path side cover 27 and the conveyance guide 28 is not particularly limited, and is made of hard resin, ceramic, metal, or the like.

The light source 23 includes a plurality of light emitting elements 23a disposed so as to surround the center of the imaging region 22a in plan view, an annular prism (light guide) 23b disposed on the light emitting element 23a, and an annular shape. The annular illumination includes an annular light diffusion film 23c disposed on the inner peripheral side of the prism 23b. By using the annular illumination, the coin 100 passing through the imaging region 22a can be illuminated uniformly from the surroundings, so that a clear image of the coin 100 can be taken. In the annular illumination, the light emitting elements 23a arranged around the imaging region 22a may be enclosed in a single manner as shown in FIG. 3, or may be enclosed more than twice.

As the light emitting element 23a, a light emitting diode (LED) is suitable. The wavelength range of the light emitted from the plurality of light emitting elements 23a is not particularly limited, and infrared light, visible light, or the like can be used. From the viewpoint of increasing the color detection ability of the coin 100, white light is preferable. That is, a white LED is preferably used as the light emitting element 23a. Further, each of the plurality of light emitting elements 23a may emit light in different wavelength ranges, and for example, white light may be obtained by three types of LEDs that respectively emit red, green, and blue light. The light emitting surface of each light emitting element 23a is provided above, and the light emitted from the light emitting element 23a enters the prism 23b.

As shown in FIG. 4, the cross section of the prism 23b includes a lower surface (light incident surface) that faces the light emitting surface of the light emitting element 23a, and a reflective surface that reflects upward light incident from the lower surface in the direction of the imaging region 22a. And a light exit surface facing the light diffusion film 23c. The arrows in FIG. 4 indicate the optical path of the light emitted from the light emitting element 23a. The light diffusion film 23c is a member provided to uniformly illuminate the imaging region 22a, and is not particularly limited as long as it has a function of diffusing light.

The imaging element 24 includes a photoelectric conversion unit 24a in which a CCD image sensor or the like is disposed, and a lens unit 24b that receives light reflected by the coin 100 passing through the imaging region 22a and forms an image on a light receiving surface of the photoelectric conversion unit 24a. Including. It is preferable that the image sensor 24 is disposed immediately below the imaging region 22a. When the imaging device 24 is arranged in an oblique direction with respect to the imaging region 22a and the coin 100 is imaged from the oblique direction, the coin image to be collected may be distorted because the coin 100 may rotate during conveyance. is there.

As shown in FIGS. 1 and 3, when the coin 100 enters the imaging area 22a, the light source 23 emits light toward the imaging area 22a (transparent portion 22) and the surface of the coin 100 to be conveyed (either one of them). The image sensor 24 receives the light reflected by the surface) and forms an image, whereby a coin image is collected. That is, the image capturing device according to the first embodiment includes a control unit that controls the light source 23 and the image sensor 24 so that a coin image is sampled every time the coin 100 passes through the image capturing region 22a of the image sensor 2. doing.
The image sensor 2 may or may not have a timing sensor (photo sensor) for detecting the arrival of the coin 100.

Here, when the coin 100 is transported at a high speed in order to improve the processing speed of the coin-like medium processing machine, the behavior of the coin 100 being transported is likely to be unstable. When the coin 100 is lifted from the transport surface in the imaging region 22a, the imaging element 24 may be out of focus. Further, when identifying a plurality of types of coins 100 having different diameters, the imaging region 22a is designed to be larger than the largest diameter coin 100 among the coins 100 to be identified, and therefore the smallest diameter coin that is conveyed at high speed. 100 does not necessarily pass through a certain part of the imaging region 22a, and the imaging position is not constant. Furthermore, since the coin 100 can be rotated in the horizontal direction, even if it is the same type of coin that has been normally imaged, it may be a coin image with a different orientation. Therefore, in order to perform accurate identification, it is required to collect as clear a coin image for identification processing as possible.

Next, a coin image collecting method by the image collecting apparatus according to the first embodiment will be described with reference to FIGS. 5 to 9. Subsequently, a coin image collecting method by a conventional image collecting apparatus will be described with reference to FIGS. Will be described. The method of Embodiment 1 differs from the conventional method in the illumination method of the light source 23 when collecting coin images.

FIG. 5 is a diagram illustrating a light emission state of the light emitting arrays 23A, 23B, 23C, and 23D in the times A to D within the single exposure period with respect to the image sensor 24. As shown in FIG. 5, in this embodiment, the light source 23 provided in the image sensor 2 is divided into four light emitting arrays (light emitting units) 23A, 23B, 23C, and 23D. In the present invention, the number of divisions of the light source 23 can be any number of 2 or more, and preferably 2 to 4. When the coin 100 is transported at a high speed, the coin 100 passes through the imaging region 22a in a short period of time, so that a single exposure period for the imaging element 24 cannot be ensured for a long time. Therefore, if the number of divisions of the light source 23 is excessively increased, the light emission amount of each light emitting unit may be insufficient.

Each of the light emitting arrays 23A, 23B, 23C, and 23D corresponds to a drive unit that is controlled independently of each other, and when imaging one coin 100, each of the four light emitting arrays 23A, 23B, 23C, and 23D. The timing of the light emission period is controlled to be different from each other. Here, “the timings of the light emission periods are different from each other” means that at least one of the start time and the end time of the light emission periods is different, and preferably the light emission periods do not overlap each other. Each light emitting array 23A, 23B, 23C, 23D includes at least one light emitting element 23a, and the light emitting elements 23a in each light emitting array 23A, 23B, 23C, 23D emit light at the same timing. Be controlled.

The single exposure period for the image sensor 24 is a period from when the shutter of the image sensor 24 is opened until it is closed, and corresponds to a period during which one coin 100 is imaged. FIG. 6 is a waveform diagram showing the relationship between the single exposure period for the image sensor 24 and the light emission periods of the four light emitting arrays 23A, 23B, 23C, and 23D in the illumination method of the first embodiment. As shown in FIGS. 5 and 6, each light-emitting array 23A, 23B, 23C, 23D obtained by dividing the annular illumination is sequentially arranged for each single exposure period for the image sensor 24, that is, for each period for imaging one coin 100. Light is emitted at different timings, and the coins 100 are individually illuminated from different directions.

FIG. 7A is a diagram showing a state when the light emitting array 23A illuminates the coin 100, and FIG. 7B is a luminance when the portion surrounded by a dotted line in FIG. 7A is imaged. It is a graph which shows. As shown in FIG. 7A, during time A when the light emitting array 23 </ b> A illuminates the coin 100, a bright part and a dark part (shadow) are generated in the vicinity of the convex part 101 existing on the surface of the coin 100. That is, the step surface of the convex portion 101 facing the light emitting array 23A becomes a bright portion because the light of the light emitting array 23A is strongly reflected, and the step surface of the convex portion 101 facing the light emitting array 23C reaches the light of the light emitting array 23A. Because it is difficult, it becomes a dark part. FIG. 7B illustrates a step surface (dark portion) facing the light emitting array 23C of the convex portion 101 at time A and the luminance in the vicinity thereof.

FIG. 8A is a diagram showing a state when the light emitting array 23C illuminates the coin 100, and FIG. 8B is a luminance when the portion surrounded by the dotted line in FIG. 8A is imaged. It is a graph which shows. As shown in FIG. 8A, even during the time C when the light emitting array 23 </ b> C illuminates the coin 100, a bright portion and a dark portion (shadow) are generated in the vicinity of the convex portion 101 existing on the surface of the coin 100. That is, the step surface of the convex portion 101 facing the light emitting array 23A is a dark portion because the light of the light emitting array 23C is difficult to reach, and the step surface of the convex portion 101 facing the light emitting array 23C strongly reflects the light of the light emitting array 23C. It becomes a bright part from that. FIG. 8B illustrates the level difference surface (bright portion) of the convex portion 101 facing the light emitting array 23 </ b> C at time C and the luminance in the vicinity thereof.

The coin image is created based on the total amount of light received by the image sensor 24 within a single exposure period corresponding to the imaging period of one coin 100. Accordingly, the step surface of the convex portion 101 facing the light emitting array 23 </ b> C is imaged based on the sum of the luminances of the times A to D. Here, when the sum of the luminances in FIGS. 7B and 8B is obtained, it is as shown in FIG. As shown in FIG. 9, the contrast on the surface of the step facing the light emitting array 23C of the convex portion 101 is large, and the shadow of the pattern on the surface of the coin 100 is emphasized and easy to detect. Thus, according to the illumination method of the present embodiment, a coin image in which the brightness corresponding to the unevenness on the surface of the coin 100 becomes clearer is obtained.

On the other hand, as shown in FIG. 10, in the conventional illumination method, the light emission periods of the plurality of light emitting elements 23 a are all the same, and are synchronized with the timing of the exposure period for the image sensor 24. In FIG. 10, for convenience of comparison with FIG. 6, the light emitting arrays 23 </ b> A, 23 </ b> B, 23 </ b> C, and 23 </ b> D are shown as being divided, but actually, the entire light source 23 is driven integrally and controlled independently. There is no drive unit. Therefore, as shown in FIG. 11, the collected coin image is the one when the coin 100 is illuminated from all directions. For this reason, as shown in FIG. 12, the contrast on the step surface of the convex portion 101 facing the light emitting array 23C is small, and the shading due to the concave / convex pattern on the surface of the coin 100 is canceled out and is difficult to detect.

Control of the light emission timing in this embodiment is performed using the said control part. That is, the control unit performs light source control that varies the timings of the light emitting periods of the four light emitting arrays 23A, 23B, 23C, and 23D within a single exposure period for the image sensor 24.

The control unit includes a conveyance control unit, a magnetic detection unit, an imaging control unit, and an image detection unit. A conveyance control part controls conveyance of the coin 100 by the conveyance part 21 comprised by the conveyance belt 21a etc. FIG. The magnetic detection unit detects the coin 100 passing through the conveyance path based on the output of the magnetic detection sensor 1. The imaging control unit controls the light emission timing of the light emitting element 23 a and the imaging timing of the imaging element 24. The image detection unit creates a coin image based on the output of the image sensor 24. A coin-like medium processing machine such as an amplifier circuit, a filter circuit, an AD converter circuit, and a drive circuit is appropriately provided between the control unit and sensor constituent members such as the magnetic detection sensor 1, the light emitting element 23a, and the imaging element 24. A general circuit in the field may be interposed.

Further, the coin-shaped medium processing machine includes a storage unit and an identification unit in addition to the already-described components such as the conveyance unit 21, the magnetic detection sensor 1, the light emitting element 23a, the imaging element 24, and the control unit. The storage unit stores coin information related to the coin 100 to be processed, and stores a coin image (identification processing image) captured by the image sensor 2 as the coin 100 is processed. The discriminating unit discriminates / determines the type, authenticity, damage (dirt), etc. of the coin 100 by comparing the coin information with the image for identification processing.

As a physical configuration of the control unit and the identification unit, for example, a software program for realizing various processes, a CPU (central processing unit) that executes the software program, various hardware controlled by the CPU, FPGA (Field Programmable Gate Array) etc. are included. For storing software programs and data necessary for the operation of each unit, a storage unit, a memory such as a RAM and a ROM provided separately, a hard disk, and the like are used.

Examples of the physical configuration of the storage unit include a storage device such as a volatile or nonvolatile memory or a hard disk. A memory | storage part is utilized in order to memorize | store various data required for the process performed with a coin-shaped medium processing machine.

As described above, according to the image capturing device of the present embodiment, the light emission period of each of the plurality of light emitting units (light emitting arrays 23A, 23B, 23C, 23D) within a single exposure period with respect to the image sensor 24. By varying the timing, a high-contrast coin image in which the brightness corresponding to the unevenness on the surface of the coin 100 becomes clearer is obtained. Therefore, the ability to identify a coin 100 having a gentle step, such as a portrait, is improved. In addition, since it is not necessary to separately photograph a plurality of types of coins 100 with high-angle illumination and low-angle illumination, the number of light sources can be reduced, and the sensor size can be reduced. Furthermore, since an image is captured in a single exposure period, the number of acquired images is one, and an increase in image processing time can be prevented.

In the present embodiment, as shown in FIG. 4, the light source 23 irradiates light from a plurality of oblique directions onto the surface of the coin 100 within a single exposure period for the image sensor 24. The light irradiated from the oblique direction is more likely to be blocked by the convex portion 101 existing on the surface of the coin 100 than the light irradiated from the normal direction, and a shadow is likely to be generated in the vicinity of the convex portion 101. As a result, the contrast corresponding to the irregularities on the surface of the coin 100 becomes clearer, and a high-contrast coin image is obtained.

In the present embodiment, the plurality of light emitting units (light emitting arrays 23A, 23B, 23C, and 23D) are arranged around the imaging region 22a where the coin 100 is located at the time of imaging in plan view, and the imaging region 22a Including at least a pair of light emitting portions opposed to each other. As shown in FIG. 5, the light emitting array 23A and the light emitting array 23C face each other, and the light emitting array 23B and the light emitting array 23D face each other. By picking up an image using at least a pair of light emitting units, a clear coin image can be obtained over the entire surface of the coin even when illuminating from an oblique direction. In particular, as shown in FIGS. 3 and 5, the plurality of light emitting units (light emitting arrays 23A, 23B, 23C, 23D) are preferably arranged in an annular shape.

(Embodiment 2)
The image capturing device according to the first embodiment includes a light source that irradiates light from a plurality of oblique directions with respect to the surface of the coin within a single exposure period with respect to the imaging device. The sampling device includes a light source that irradiates light from the normal direction to each of a plurality of regions constituting the surface of the coin within a single exposure period for the image sensor. FIG. 13 is a schematic diagram illustrating the configuration of the image sensor of the image capturing device according to the second embodiment. FIG. 14 is a plan view illustrating the shape of the optical axis correction grating included in the image sensor of the image capturing device according to the second embodiment. FIG. 15 is a schematic plan view illustrating a light emitting surface of a light source provided in the image sensor. An arrow in FIG. 13 indicates a path through which light emitted from the surface emitting light source 73 enters the image sensor 24.

As shown in FIG. 13, the image sensor of this embodiment irradiates the coin 100 by reflecting the light from the surface emitting light source 73 with a beam splitter 73f. The surface-emitting light source 73 includes a light-emitting substrate 73d on which a plurality of light-emitting elements (LEDs) 73a are mounted. An optical axis correction grating 73e is provided on the light emitting surface side (light emission traveling direction) of the plurality of light emitting elements 73a. As shown in FIG. 14, the optical axis correction grating 73 e is a lattice-shaped member having 16 cylindrical cavities, and restricts the optical axis of light emitted from the surface emitting light source 73. That is, out of the light emitted from the plurality of light emitting elements 73a, light that has passed through the cylindrical cavity is taken out, whereby light having high straightness can be obtained. Further, a resin grating 73g is sandwiched between the light emitting substrate 73d and the optical axis correction grating 73e. The resin lattice 73g is a lattice-like spacer that connects the light emitting substrate 73d and the optical axis correction lattice 73e. The resin grating 73g may be integrated with the optical axis correction grating 73e. In this case, the resin grating 73g is not used, and the light emitting substrate 73d and the optical axis correction grating 73e are directly connected.

As shown in the light emitting surface of the surface emitting light source 73 in FIG. 15, the plurality of light emitting elements 73a are divided into 16 light emitting portions 73A corresponding to 16 cylindrical cavities through which the light emission passes. Each light emission timing is different. The numbers written on the light emitting surface of the surface light source 73 in FIG. 15 indicate the light emission order of the light emitting units in the illumination method of the second embodiment. FIG. 16 is a waveform diagram illustrating the relationship between the exposure period for the image sensor and the light emission periods of a plurality of light emitting units in the illumination method according to the second embodiment. As shown in FIGS. 15 and 16, the light emitting unit 73A is divided into 16 light emitting units 73A, and the divided light emitting units 73A individually illuminate the coins 100 at different timings. A minute scratch can be imaged more clearly. Therefore, it is suitable for capturing a pattern such as a portrait having a gentle step as an edge (contour) on the surface of the coin 100.

The beam splitter 73f reflects the light incident from the surface emitting light source 73 toward the imaging region, and transmits the light reflected by the surface of the coin 100 passing through the imaging region. The light that has passed through the beam splitter 73f is picked up by the image pickup device 24, whereby a coin image is obtained. The beam splitter 73f has a traveling direction of light emitted from the surface emitting light source 73 and a reflecting surface directed obliquely with respect to the transport surface of the coin 100. For example, as shown in FIG. A reflective surface inclined at 45 ° with respect to 100 transport surfaces is provided. The beam splitter 73f only needs to have both a function of reflecting incident light and a function of transmitting incident light. 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 exhibiting a characteristic of 1 is preferably used.

In the present embodiment, as shown in FIG. 13, the surface-emitting light source 73 is viewed from the normal direction with respect to each of a plurality of partitioned areas constituting the imaging area within a single exposure period for the imaging element 24. Irradiate light. In the conventional general surface light emission, the light and darkness corresponding to the small unevenness on the surface of the coin 100 becomes unclear due to the incident component from the oblique direction included in the diffused light. While obtaining the reproducibility of the hue, which is an advantage of the light emitting light source 73, it is possible to clearly capture the pattern on the surface of the coin 100 and minute scratches. Therefore, the ability to identify a coin 100 having a gentle step, such as a portrait, is improved.

Further, when unused coins (new coins) are imaged with low-angle illumination, the reflected light in the normal direction of the coins is small and a dark image tends to be formed. Therefore, the image capturing device according to the present embodiment that irradiates light from the normal direction to the surface of the coin is suitable for detecting minute scratches on the new coin.

Further, as shown in FIG. 16, since the divided exposure is performed within a single exposure period for the image sensor 24, the data amount of the coin image is not increased, and high-speed processing of the coin image is possible.

In the present embodiment, as shown in FIGS. 13 and 14, a cylindrical optical axis correction grating 73e that separates the light emitted from each of the plurality of light emitting units 73A is provided. By passing through the cylindrical optical axis correction grating 73e, light having high straightness can be obtained in the coin 100. Thereby, the surface of the coin 100 can be partially illuminated with linear light, and the pattern on the surface of the coin 100 and minute scratches can be imaged more clearly.

In the present embodiment, the plurality of light emitting portions 73A are arranged in a matrix as shown in FIG. Thereby, a clear image is obtained on the entire surface of the coin 100.

In the present embodiment, a beam splitter that reflects a part of light emitted from each of the plurality of light emitting units toward the surface of the coin 100 is provided. According to such a configuration, it is possible to irradiate the coin 100 with light that is highly straight from the normal direction, and it is possible to obtain a coin image with excellent color reproducibility.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. The configuration of the above embodiment may be appropriately deleted, changed, or combined within a scope that does not depart from the gist of the present invention.

As described above, the present invention relates to an image capturing device, a coin-like medium processing machine, and an image capturing method, and a useful technique that can collect a high-contrast coin-like medium image by a simple mechanism suitable for downsizing and high-speed processing. It is.

1: Magnetic detection sensor 2: Image sensor 3: Damage detection sensor 4: Phosphorescence detection sensor 5: Fluorescence detection sensor 21: Conveying part 21a: Conveying belt 21b: Conveying pin 22: Transparent part 22a: Imaging region 23: Light source 23a: Light emitting elements 23A, 23B, 23C, 23D: Light emitting array 23b: Prism (light guide)
23c: light diffusion film 24: imaging device 24a: photoelectric conversion unit 24b: lens unit 26: housing 27: transport path side cover 28: transport guide 73: surface emitting light source 73a: light emitting element 73A: light emitting unit 73d: light emitting substrate 73e: Optical axis correction grating 73f: Beam splitter 73g: Resin grating 100: Coin 101: Convex portion of coin surface

Claims (10)

An image collecting device for collecting an image for identification processing of a coin-shaped medium,
A light source that has a plurality of light emitting units and irradiates the surface of the coin-like medium with light emitted by the plurality of light emitting units;
An image sensor that images light reflected from the surface of the coin-like medium and images the coin-like medium;
An image capturing apparatus comprising: a control unit that performs control to vary timings of the light emission periods of the plurality of light emitting units within a single exposure period with respect to the imaging element. The image capturing apparatus according to claim 1, wherein the light source irradiates light from a plurality of oblique directions to the surface of the coin-shaped medium within a single exposure period for the image sensor. The plurality of light emitting units include at least a pair of light emitting units that are arranged around an imaging region in which the coin-like medium is located at the time of imaging in plan view and that face each other with the imaging region interposed therebetween. The image capturing apparatus according to claim 2, wherein the image capturing apparatus is characterized in that: The image capturing apparatus according to claim 3, wherein the plurality of light emitting units are arranged in an annular shape. The image capturing apparatus according to claim 1, wherein the light source emits light from a normal direction to each of a plurality of partitioned areas within a single exposure period for the image sensor. The image capturing apparatus according to claim 5, wherein the plurality of light emitting units are arranged in a matrix. The image capturing device according to claim 5, further comprising a cylindrical optical axis correction grating that partitions light emitted from each of the plurality of light emitting units. The image capturing device according to claim 5, further comprising a beam splitter that reflects a part of light emitted from each of the plurality of light emitting units toward a surface of the coin-shaped medium. . A coin-shaped medium processing machine comprising the image sampling device according to claim 1. An image collecting method for collecting an image for identification processing of a coin-shaped medium,
Within a single exposure period for the image sensor, the controller
A light source control for causing each of the plurality of light emitting units constituting the light source to emit light at different timings to irradiate the surface of the coin-shaped medium; and
Based on the reflected light of the surface of the coin-shaped medium that the image sensor receives through the single exposure period, image capturing for capturing an image of the coin-shaped medium;
An image capturing method characterized in that:

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