JPH10222715A - Work image fetching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate work discrimination in image processing and to improve precision by providing a diaphragm plate that limits an image pickup range at a position where reflected light from work strikes. SOLUTION: When a coin 3 moves on a conveyor 14 and approaches an image pickup range 6 of a work image fetching device 1, position sensors 18 that are incorporated by the device 1 operate. When the sensors 18 detect that the coin 3 is located in the range 6, an LED 2 emits light. Irradiated light from the LED 2 is reflected by a prism 7 and transmit a glass plate 8, and the coin 3 is irradiated with the irradiated light. Reflected light from the coin 3 transmit the plate 8, is converged by a diaphragm plate 5, forms an image by a lens 9 and is received by a CCD 4. An image that is acquired at the CCD 4 has an edge part that is whitely embossed. The coin 3 is discriminated based on the image. Concretely, e.g. the class of a coin is decided by detecting the size of a circular edge part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a work image capturing device for capturing an image of a work such as a coin. More specifically, the present invention relates to an improvement in an optical system of a workpiece image capturing device.

[0002]

2. Description of the Related Art As shown in FIG.
In the work image capturing device 101 that captures the image No. 00,
When a plurality of types of works 100 having different sizes sequentially conveyed by the conveyor 102 pass through a predetermined imaging range 103, the work 100 is irradiated with illumination light from an illumination light source 104, and reflected light from the work 100 is reflected. An image pickup unit, for example, the CCD 105 receives light to image the work 100. In the obtained image, as shown in FIG. 9, the edge portion 106 of the work becomes white, and the other portions become black (hatched portions in the figure). And this edge part 10
6, the type of the work 100 is determined.

[0003]

However, in the work image capturing apparatus 101 described above, the imaging range 103 by the CCD 105 and the lens 107 is set to be considerably wider than the work 100 with a margin. When the irradiation light from the object is irregularly reflected, this may also be captured in the image. For this reason, a white portion may be imprinted on the image other than the edge portion 106 of the work, and in this case, it is difficult to determine the type of the work.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work image capturing device capable of preventing the printing of an extra object other than the work.

[0005]

In order to achieve the above object, according to a first aspect of the present invention, a workpiece is irradiated with illumination light from an illumination light source, and reflected light from the workpiece is captured as an image by an imaging means. In the work image capturing apparatus having the above configuration, an aperture plate for limiting an imaging range of the reflected light to the imaging means is provided at a position where the reflected light from the work is applied.

Accordingly, the reflected light from the work is narrowed down by the aperture plate, and the imaging range of the reflected light is limited, so that the aperture plate is directly imaged except for the work and its vicinity. As a result, irregular reflections or the like generated around the work are not printed, and the entire periphery of the work is completely black, so that the work of discriminating the work is facilitated and the accuracy is improved.

Further, in the work image capturing apparatus according to the second aspect, the work is conveyed along the conveyance path and is illuminated by the illumination light source within a predetermined imaging range, and the illumination light source is composed of a large number of annularly arranged light sources. It consists of a light source and illuminates the work in dark field. Therefore, since the work is irradiated from the entire circumference, the outline of the work clearly appears. In addition, since the work is illuminated in the dark field, the edge of the work emerges white in a black background, and the accuracy of work determination is further improved.

Further, in the workpiece image capturing device according to the third aspect, the aperture plate is held by a mounting member to which a number of light sources are attached, and the imaging range to the imaging means is limited by a circular opening formed in the aperture plate. Like that. Therefore, since the stop plate is held by the mounting member to which a large number of light sources are mounted, light rays from the illumination light source do not directly hit the stop plate. For this reason, the aperture plate is not imaged brightly, but is always imaged completely black.

Further, in the work image capturing device according to the fourth aspect, the work is a coin. Therefore, it is possible to easily determine the coin.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings. As shown in FIGS. 1 and 2, a work image capturing device 1 irradiates illumination light from an LED 2 as an illumination light source to a coin 3 as a work, and reflects a reflected light from the coin 3 as a CCD 4 as an imaging unit. To capture as an image. In the workpiece image capturing device 1, the diaphragm plate 5 for limiting the imaging range 6 of the reflected light to the CCD 4 is moved to the coin 3.
It is provided at a position where the reflected light from the camera falls.

Further, in the present embodiment, the work image capturing device 1 includes an LED 2 that emits an infrared ray, a prism 7 that changes the optical path direction of light emitted from the LED 2, and a glass that determines the imaging surface of the coin 3. A plate 8, an aperture plate 5 for reducing the reflected light from the coin 3, a lens 9 for condensing the reflected light, and a CCD 4 for receiving the collected reflected light are provided.

The LED 2 has a support substrate 10 as an attachment member.
, And a number of coins 3 are annularly arranged so as to surround the coin 3 to be imaged. The prism 7 has an annular shape and bends the optical path of the irradiation light from the LED 2 so as to be directed substantially toward the center of the glass plate 8. The prism 7 has a projection 7 a that fits into the through hole 10 a of the support substrate 10. Thereby, the relative position between the prism 7 and the support substrate 10, and the relative position between the prism 7 and the LED 2 are maintained.

Here, the LED 2 and the prism 7 are arranged in the lower part of the work image capturing device 1, that is, in the vicinity of the periphery of the coin 3. For this reason, the irradiation light from the prism 7 is incident on the surface of the coin 3 at an angle close to parallel. As a result, light reflected by the flat portion of the surface of the coin 3 is not received by the CCD 4, and only light reflected by the edge portion of the surface of the coin 3 is received by the CCD 4. That is, in the image obtained by the CCD 4, as shown in FIG. 3, only the edge portion 11 of the coin surface becomes white due to reflection, the other flat portion (hatched portion in the drawing) becomes black, and dark-field illumination and Become.

A diffusion plate 12 is disposed substantially vertically between the exit surface 7b of the prism 7 and the glass plate 8. The diffusion plate 12 has a ring shape and is fitted inside the prism 7. The diffusion plate 12 is made of a translucent member, and irradiates the glass plate 8 by diffusing the irradiation light from the LED 2. For this reason,
The point light from many LEDs 2 is diffused and irradiates the glass plate 8 as an annular soft light beam. As a result, substantially uniform irradiation light can be given to the entire circumference of the coin 3, so that the edge of the coin 3 in the obtained image becomes uniform, and the accuracy of coin discrimination can be improved. Note that the diffusion plate 12 is not limited to a vertically arranged one, and may be in close contact with the exit surface 7b of the prism 7 as shown by an imaginary line in FIG.
Alternatively, the light may be diffused by embossing on the exit surface 7b of the prism.

The glass plate 8 is inserted into the through hole 13a of the bottom plate 13 of the work image capturing device 1. The size of the glass plate 8 is slightly larger than the imaging range 6 narrowed by the diaphragm plate 5. Then, the coin 3 is adhered to the glass plate 8. Therefore, the set position of the coin 3 is kept constant. The coin 3 is moved by the conveyor 14, and the image is taken in while moving.

A lower light-shielding plate 15 is attached to a surface of the prism 7 facing the coin 3. Lower shading plate 15
Has a circular outer shape and an inner peripheral portion formed integrally with the diaphragm plate 5. However, the lower light shielding plate 15 and the diaphragm plate 5 are separate members,
These may be joined. This diaphragm plate 5
The lower light-shielding plate 15 is made of a vinyl chloride sheet and is painted black with carbon particles. Therefore, the reflected light, which is infrared light, is not reflected by the diaphragm plate 5.

Further, since the lower light-shielding plate 15 is attached to the surface of the prism 7 facing the coin 3, it is possible to prevent irregularly reflected light inside the prism 7 from leaking outside the prism 7. This prevents irregularly reflected light from irradiating the coin 3 and its surroundings.

The reflected light from the coin 3 is stopped down by the circular opening 5a of the stop plate 5. That is, the outer peripheral portion of the reflected light is not received by the CCD 4. This allows
As shown in FIG. 3, an image obtained by the CCD 4 has a glass plate 8 imprinted in the vicinity of the coin 3 and an aperture plate 5 directly imprinted around the glass plate 8. However, since the glass plate 8 near the coin 3 and the aperture plate 5 directly photographed are both black, no boundary can be found in the image.

In this embodiment, since the aperture plate 5 is attached to the lower surface of the prism 7, the distance from the coin 3 is reduced, and the irregularly reflected portion of the reflected light can be removed before being diffused. Therefore, it is possible to reliably prevent the peripheral portion of the coin 3 from becoming bright due to the irregular reflection.

Further, the upper light shielding plate 1 is provided on the upper surface of the support substrate 10.
6 is attached. The upper light-shielding plate 16 has an annular shape and a through-hole 16 a fitted into the projection 7 a of the prism 7.
Further, on the inner side surface of the prism 7, a horizontal light shielding plate 17 which is integrated with the upper light shielding plate 16 and is in contact with the diaphragm plate 5 is attached. Each of the light shielding plates 16 and 17 is made of a sheet made of vinyl chloride and is coated with carbon particles or contains carbon particles. Therefore, the reflected light, which is infrared light, is not reflected by these light shielding plates 16 and 17.

The light shielding plates 16 and 17 prevent the irregularly reflected light from the prism 7 from leaking into the prism 7 and from passing through the support substrate 10 and leaking. This prevents irregularly reflected light from irradiating the upper surface of the diaphragm plate 5, that is, the surface imaged by the CCD 4. Therefore, since the aperture plate 5 is reliably printed in black, the accuracy of discriminating the coin 3 can be improved.

On the other hand, the range in which an image is captured by the lens 9 and the CCD 4, that is, the imaging range 6, is set larger than the opening 5a of the diaphragm plate 5 so as to allow a margin for reading. In the present embodiment, not only the edge of the opening 5a of the aperture plate 5, but also a part of the inner peripheral portion of the upper light shielding plate 16 and the horizontal light shielding plate 17 are read. These diaphragm plate 5 and light shielding plate 1
Light rays do not hit the surfaces of the CCDs 6 and 17 facing the CCD 4, and the read image becomes black except for the coin 3 in the read image.

A procedure for capturing an image of the coin 3 by the work image capturing device 1 will be described below. When the coin 3 moves on the conveyor 14 and approaches the imaging range 6 of the workpiece image capturing device 1, the position sensor 18 incorporated in the workpiece image capturing device 1 operates. When the position sensor 18 detects that the coin 3 is located in the imaging range 6, the LED 2 emits light.

The irradiation light from the LED 2 is reflected by the prism 7 and passes through the glass plate 8 to irradiate the coin 3. The reflected light from the coin 3 passes through the glass plate 8, is stopped down by the stop plate 5, forms an image by the lens 9, and is received by the CCD 4. The image obtained by the CCD 4 is, for example, an image in which the edge portion 11 of the coin 3 is raised white as shown in FIG. Then, the coin 3 is determined based on this image. Specifically, for example, the type of the coin is determined by detecting the size of the circular edge portion 11.

The conveyor 14 is moving during the processing from the emission of the LED 2 to the capture of the image by the CCD 4.
Then, a large number of coins 3 continuously pass through the imaging range 6, and each coin 3 is determined.

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the size of the glass plate 8 is set to be slightly larger than the imaging range 6 narrowed down by the aperture plate 5, but is not limited to this, and is sufficiently larger than the imaging range 6 as shown in FIG. It may be large. In this case, it is preferable to attach an annular light-shielding sheet 19 around the imaging range 6 on the glass plate 8. Thereby, it is possible to prevent irregularly reflected light leaking from the reflecting surface 7c and the emitting surface 7b of the prism 7 from irradiating the glass plate 8 and the coin 3. The light-shielding sheet 19 is preferably mounted at a position as close as possible to the surface of the workpiece in the optical path direction of the reflected light (the vertical direction in FIG. 4) and at which the irradiation light is not incident. As a result, the light-shielding sheet 19 is out of the imaging range 6, so that the light-shielding sheet 19 does not appear in the image and the black portion does not become bright.

In this embodiment, the diaphragm plate 5 is integrated with the lower light-shielding plate 15 attached to the prism 7, but the mounting position of the diaphragm plate 5 is not limited to this. For example, as shown in FIG. 5, the aperture plate 5 may be provided integrally or separately on the inner peripheral edge of the upper light shielding plate 16 attached to the support substrate 10.
According to the mounting position of the diaphragm plate 5, the diaphragm plate 5 is
Is mounted on the upper side of the supporting substrate 10 provided with
Irradiation light from the ED 2 does not impinge on the upper surface of the aperture plate 5, and the aperture plate 5 can be more reliably made black in the obtained image. In this case, the lower light shielding plate 15 attached to the prism 7 is moved from the diffusion plate 12 to the horizontal light shielding plate 17.
It is enough if it is long enough. In addition, the aperture plate 5 can also narrow the imaging range 6 so that the portion of the image other than the coin 3 is completely black.

Further, the mounting position of the diaphragm plate 5 is not limited to the upper surface of the support substrate 10 as shown in FIG.
May be the lower surface. Also in this case, the diaphragm plate 5 is LE
Since it is mounted on the upper side of D2, the irradiation light from the LED 2 does not hit the upper surface of the diaphragm plate 5.

Further, the mounting position of the aperture plate 5 may be on the upper surface of the glass plate 8. As a result, portions of the reflected light from the coin 3 other than the imaging range 6 cannot reach above the glass plate 8. For this reason, the irregularly reflected portion of the reflected light can be reliably eliminated.

On the other hand, the shape of the prism 7 is not limited to those shown in FIGS. 1 and 2, and as shown in FIGS. 6 and 7, the fixed groove 7d into which the diffusion plate 12 is inserted, the lower light-shielding plate 15, and the horizontal light-shielding plate. The plate 17 may have a support portion 7e to be backed. In this case, since the upper end of the diffusion plate 12 is positioned by being inserted into the fixing groove 7d, there is no deviation.
Further, the lower light-shielding plate 15 and the horizontal light-shielding plate 17 are supported by the support portion 7e.
Are determined, these positions are stabilized, and leakage of irregularly reflected light from the prism 7 is reliably prevented.

Further, even in the prism 7 shown in FIGS. 6 and 7, the diaphragm plate 5 is installed at the inner peripheral side of the inner edge of the lower light shielding plate 15 as shown in FIG. 6, or as shown in FIG. The upper light shielding plate 16 can be located on the inner peripheral side of the inner edge portion. Therefore, when designing the work image capturing apparatus 1, various types of prisms 7 can be selected and designed according to required conditions, and the installation position of the aperture plate 5 can be designed differently.

Further, in the above embodiment, the prism 7
Is provided, but this may be omitted. For example, L
The coin 3 may be directly irradiated by the ED.

[0033]

As is apparent from the above description, in the work image capturing apparatus according to the first aspect, an aperture plate for limiting an imaging range of reflected light to the imaging means is provided at a position where the reflected light from the work hits. Therefore, the diaphragm plate is directly imaged except for the work and its vicinity. For this reason, irregular reflection or the like generated around the work is not printed, and the entire periphery of the work is completely black, so that the work can be easily identified in the image processing and the accuracy can be improved.

Further, in the work image capturing device according to the second aspect, the work is conveyed along the conveyance path and is illuminated by the illumination light source within a predetermined imaging range, and the illumination light source is composed of a large number of annularly arranged light sources. Since the work is composed of a light source and illuminates the work in the dark field, the work is illuminated from all around, so that the contour of the work can be clearly raised. In addition, since the work is illuminated in a dark field, the edge of the work appears white in a black background, so that the accuracy of work determination can be further improved.

Further, in the workpiece image capturing apparatus according to the third aspect, the aperture plate is held by the mounting member to which a number of light sources are mounted, and the imaging range of the imaging means is limited by the circular opening formed in the aperture plate. Therefore, the illumination light from the illumination light source does not directly irradiate the aperture plate. For this reason, the aperture plate is not imaged brightly, and the entire periphery of the work is always imaged completely black. Therefore, the accuracy of work determination can be improved.

Further, in the work image capturing device according to the fourth aspect, since the work is a coin, it is possible to easily determine the type of the coin.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an entire work image capturing device of the present invention.

FIG. 2 is an enlarged cross-sectional view illustrating a periphery of a prism of the workpiece image capturing device.

FIG. 3 is a schematic diagram showing an image of a coin captured by a work image capturing device.

FIG. 4 is an enlarged sectional view around a prism showing another embodiment of the work image capturing device.

FIG. 5 is an enlarged sectional view around a prism showing still another embodiment of the work image capturing device.

FIG. 6 is an enlarged sectional view around a prism showing another embodiment of the work image capturing device.

FIG. 7 is an enlarged sectional view around a prism showing still another embodiment of the workpiece image capturing device.

FIG. 8 is a longitudinal sectional view showing the whole of a conventional work image capturing device.

FIG. 9 is a schematic diagram showing an image of a coin captured by a conventional work image capturing device.

[Explanation of symbols]

 Reference Signs List 1 work image capturing device 2 LED (illumination light source) 3 coin (work) 4 CCD (imaging means) 5 aperture plate 6 imaging area 10 support substrate (attachment member)

Claims (4)

[Claims] 1. A work image capturing device configured to irradiate illumination light from an illumination light source to a work and capture reflected light from the work as an image by an imaging unit, wherein the imaging unit captures the reflected light. A work image capturing device, wherein an aperture plate for limiting an imaging range of the work is provided at a position where the reflected light from the work shines. 2. The work is conveyed along a conveyance path and is illuminated by the illumination light source within a predetermined imaging range, and the illumination light source includes a plurality of light sources arranged in a ring, and the work is formed in a dark field. The workpiece image capturing device according to claim 1, wherein the workpiece image capturing device is illuminated. 3. The image pickup device according to claim 2, wherein the diaphragm plate is held by a mounting member to which the plurality of light sources are mounted, and a circular aperture formed in the diaphragm plate limits an imaging range to the imaging unit. 2. The work image capturing device according to item 2. 4. The work image capturing device according to claim 1, wherein the work is a coin.