JP3993268B2 - Illumination device and illumination light diffuser used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an illumination device for illuminating an object to be observed when pattern recognition is performed by image sensing using a CCD camera, and an illumination light diffuser used for the illumination device.
[0002]
[Prior art]
In unmanned factories, etc., products are detected by image sensing using a CCD camera to automatically identify the type of product (observation) sent by the conveyor, and to perform quality control and final inspection of the product. The pattern recognition is performed by capturing the outer shape and surface state of the pattern and comparing it with a previously stored pattern.
In this case, it is preferable to perform illumination with as little shadow as possible in order to correctly capture the appearance of the product.
[0003]
For this reason, in the past, with a product to be photographed with a CCD camera, a large number of point light sources such as light bulbs and line light sources such as fluorescent lamps are arranged around the CCD camera so that light is evenly distributed from above the product. It is supposed to be irradiated.
However, for example, when a large number of point light sources are used, shadows may be formed as many as the number of point light sources, and pattern recognition may be difficult to perform.
Moreover, both the point light source and the line light source need to be provided with a socket and its wiring for each light source, and not only the lighting equipment is large and complicated, but also the heat generated by the light source itself adversely affects electronic devices such as a CCD camera. There was a problem of affecting.
[0004]
Therefore, as shown in FIG. 5 , it has been proposed to illuminate by arranging four planar light-emitting bodies 41 made of a flat light guide 40 obliquely upward around the product.
The planar light-emitting body 41 has a light incident surface 44 attached to a linear light emitting portion 43 formed at the front end of the light guide 42 at one end edge, and the other edge and back surface of the light guide. In addition to being formed on the reflection surface 45 that reflects the light traveling inside the body 40 to the surface side, the surface is formed on the light irradiation surface 46.
According to this, it is only necessary to mount and arrange the planar light-emitting body 41 on each of the light emitting portions 43 of the four light guides 42, the facility itself is relatively simplified, and the light source itself is a CCD camera. Since it can be installed away from the camera, there is an advantage that even if the light source generates heat, the CCD camera is not adversely affected.
[0005]
[Problems to be solved by the invention]
However, since illumination can be performed only from four directions when illuminating using four planar light emitters 41, for example, when illuminating a spherical product, there are four directions facing the planar light emitter 41. Depending on the product shape, the product becomes brighter and a light / dark distribution is generated, and when the pattern is recognized, the shape may not be correctly grasped.
In order to solve this problem, the number of planar light emitters 41 may be increased so as to form a regular polygon. However, in this case, light guides 42 are required by the number of flat light emitters 41. Therefore, when a large number of point light sources and line light sources are arranged, the lighting equipment becomes large as much as the number of sockets required.
That is, if the lighting equipment is to be simplified, pattern recognition cannot be performed accurately, and if the pattern recognition is to be performed accurately, the lighting equipment becomes large.
[0006]
In addition, for aircraft parts such as bolts, nuts, and screws that have extremely strict quality control, a final inspection will be performed to check for dents and scratches that may occur when they are transported in the factory. However, in this case, when light is irradiated uniformly from obliquely above the product, a new problem has arisen that it is difficult to find dents and scratches formed on the surface of the product.
[0007]
Therefore, the present invention can accurately capture the shape of the observation object with extremely simplified illumination without using a large-scale illumination facility, and at the same time, makes it easy to find the irregularities formed on the surface. This is a technical issue.
[0008]
[Means for Solving the Problems]
In order to solve this problem, the present invention comprises a ring-shaped light guide in which a ring-shaped light emitting portion is formed, and an illumination light diffuser attached to the light emitting portion,
In the ring-shaped light guide, the light emitting part is equiangularly divided into a plurality of light emitting parts, and the ring shaped light emitting part is partially formed by emitting light for each light emitting part or for each of two or more light emitting parts. Formed to be capable of emitting light,
The illumination light diffuser is formed of a frustoconical light guide that expands in diameter from one end side toward the other end side, and the light emitted from the light emitting portion of the ring light guide to the one end side A light introduction part for introducing light is formed, and the inner surface of the outer peripheral surface and the other end surface is formed by a reflection surface that reflects light traveling in the light guide body, and the inner peripheral surface travels in the light guide body. An irradiation surface for diffusing and irradiating the emitted light in the space surrounded by the light guide is formed, and the irradiation surface is equiangular corresponding to each light emitting portion of the light emitting portion of the ring-shaped light guide. In particular, the light-emitting device is divided into a plurality of light-emitting regions, and includes a light-shielding unit that blocks light traveling to the other light-emitting region through the light guide body at the boundary between adjacent light-emitting regions.
[0009]
According to the present invention, when recognizing the shape of the outer shape of an observation object, if illumination light is irradiated from the entire irradiation surface, illumination is performed without shadow by uniformly irradiating light from the periphery of the observation object. So that the shape is not mistaken.
In addition, when recognizing scratches formed on the surface, by partially irradiating illumination light from the light emitting region, scratches in a direction that is not parallel to the irradiation direction, particularly scratches that are perpendicular to the irradiation direction, should be emphasized. Therefore, scratches can be accurately recognized by irradiating illumination light from an arbitrary direction.
In this case, the flaw formed obliquely with respect to the illumination light irradiation direction is not as large as a flaw perpendicular to the irradiation direction, but is more conspicuous than the case where light is evenly irradiated from around the observation object. Therefore, it is possible to accurately recognize such scratches.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic explanatory view showing an example of an illuminating device according to the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is a bottom view thereof, and FIGS. It is explanatory drawing which shows.
[0011]
The illuminating device 11 of this example improves the recognition accuracy of a flaw by selectively switching the light irradiation direction so as to make a flaw close to a right angle to the irradiation direction stand out. It consists of a ring-shaped light guide 13 having an emission part 12 and an illumination light diffuser 14 attached to the light emission part 12.
The light emitting portion 12 of the ring-shaped light guide 13 is equiangularly divided into a plurality of (for example, four) light emitting portions 15a, 15b, 16a, and 16b, and facing light emitting portions 15a and 15b, 16a and 16b. Are formed so that partial light emission is possible.
[0012]
As a means for causing the ring-shaped light guide 13 to partially emit light, for example, the light incident end portions 18 and 19 of the optical fiber bundle 17 are divided into two parts and correspond to the respective light incident end portions 18 and 19. The light emitting end portions 20a, 20b, 21a and 21b are branched two by two and arranged in arc shapes on the light emitting portions 15a, 15b, 16a and 16b. The light is selectively made incident on the light source.
Further, if light is incident on the light incident end portions 18 and 19 simultaneously by the light source device 22, all the light emitting portions 15a, 15b, 16a and 16b of the light emitting portion 12 of the ring-shaped light guide 13 are turned on simultaneously. A substantially cylindrical light beam is irradiated.
The means for causing the light emitting part 12 of the ring-shaped light guide 13 to partially emit light is not limited to this, and any means can be employed. For example, a normal ring-shaped light guide that always emits a substantially cylindrical light beam is used. It is also possible to provide a shutter that partially blocks the irradiation light in the light emitting section 12 and operate the shutter to emit an arbitrary portion.
[0013]
On the other hand, as shown in FIG. 2, the illumination light diffuser 14 is formed of a frustoconical cylindrical light guide 24 whose diameter increases from one end to the other end.
In the light guide 24, a light introduction part 25 for introducing light irradiated from the light emitting part 12 of the ring-shaped light guide 13 is formed on the one end side, and the outer peripheral surface 26 and the other end face 27 are the light guide 24. An irradiation surface 28 is formed on a reflection surface that reflects light traveling inward to the inside, and an inner peripheral surface irradiates light traveling in the light guide 24 into a space surrounded by the light guide 24. Is formed.
The light guide 24 is formed of, for example, a transparent acrylic resin, and the reflection surface formed inside the outer peripheral surface 26 and the other end surface 27 is, for example, a reflective white paint film 29W on the surface thereof. Although the black coating 29B of black paint to protect is applied and formed, this structure is an example of the embodiment of the present invention and is not limited to this.
[0014]
In addition, the irradiation surface 28 formed on the inner periphery of the light guide 24 is roughened by blasting the surface thereof, and light traveling inside the light guide 4 is surrounded by the light guide 4. When the light guide 13 is mounted on the ring-shaped light guide 13, a plurality of isometrically corresponding to the light emitting portions 15a, 15b, 16a, 16b of the light emitting portion 12 is provided. The light emitting regions 30a, 30b, 31a, 31b are divided into adjacent light emitting regions 30a, 30b, 31a, 31b at the boundary portion 32 through the light guide 24 from one light emitting region to the other light emitting region. A light blocking means 33 is provided to block the incoming light (see FIG. 3).
The light shielding means 33 is formed by forming a slit in the light guide 24 or embedding a metal plate in the slit.
[0015]
And according to this, illumination light is irradiated from the irradiation surface 28 whole region of the illumination light diffuser 14 by making all the light emission parts 15a, 15b, 16a, 16b of the ring-shaped light guide 13 light-emit (FIG. 4 (a )), The light emitting portions 15a and 15b of the ring-shaped light guide 13 are caused to emit partial light so that illumination light is emitted from the light emitting regions 30a and 30b of the illumination light diffuser 14 (see FIG. 4B), and the light emitting portion 16a. , 16b are irradiated with illumination light from the light emitting regions 31a, 31b of the illumination light diffuser 14 (see FIG. 4C).
Therefore, for example, when shape recognition of the outer shape of the observation object W is performed by image processing, if illumination light is irradiated from the entire irradiation surface 28, as shown in FIG. Since it is possible to perform illumination without shadow by irradiating light uniformly, the shape is not mistaken.
Further, in the case where scratches formed on the surface of the observation object W are recognized by image processing, illumination light is emitted from the light emitting regions 30a and 30b, 31a and 31b, respectively, so that FIGS. ), It is possible to highlight flaws in a direction that is not parallel to the irradiation direction, in particular, flaws that are orthogonal to each other, so that the flaws can be accurately recognized by irradiating illumination light from each direction. .
In this case, the scratch formed obliquely with respect to the irradiation direction of the illumination light is not as large as a scratch orthogonal to the irradiation direction, but compared with a case where light is uniformly irradiated from the periphery of the observation object W. Because it looks prominent, you can accurately recognize such scratches.
[0016]
In this example, the case where the irradiation surface 28 is divided into four light emitting regions 30a, 30b, 31a, 31b has been described, but the number of divisions is arbitrary.
Further, the illumination light is irradiated from the two light emitting regions 30a and 30b, 31a and 31b facing each other, but it may be a case where all the light emitting regions 30a, 30b, 31a and 31b are sequentially made to emit light separately.
[0017]
【The invention's effect】
As described above, according to the present invention, the 360-degree omnidirectional surrounding the observation object to be illuminated with a very simple configuration in which the illumination light diffuser is attached to the light guide having the ring-shaped light emitting portion. Therefore, when the shape is grasped by pattern recognition, the shape can be accurately grasped.
Moreover, if the light beam that illuminates the observation object is irradiated at an angle close to a right angle with respect to the central axis of the ring-shaped light guide, the light component irradiated from above is reduced, so that it is formed on the surface of the observation object. Irregular scratches stand out regardless of their direction. Therefore, when performing scratch pattern recognition by image processing for the purpose of quality control or the like, there is an excellent effect that the scratches can be accurately grasped.
Furthermore, if the light beam that illuminates the observation object is not irradiated from the entire circumference of the observation object but partially from a specific direction, scratches in a direction that is not parallel to the irradiation direction, particularly scratches that are orthogonal, stand out. By sequentially switching the irradiation direction and irradiating, there is a very excellent effect that the scratch can be accurately grasped when the pattern recognition of the scratch is performed by image processing.
[Brief description of the drawings]
FIG. 1 is a schematic explanatory view showing another lighting device according to the present invention.
FIG. 2 is a cross-sectional view thereof.
FIG. 3 is a bottom view thereof.
FIGS. 4A to 4C are explanatory views showing the relationship between the irradiation direction and the appearance of scratches. FIG.
FIG. 5 is an explanatory view showing a conventional apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Illuminating device 12 ... Light-emitting part 13 ... Ring-shaped light guide 14 ... Illumination light diffuser 15a , 15b, 16a, 16b ... light emitting part 24 ... light guide 25 ... light introducing part 26 ... outer peripheral surface 27 ... ... other end face 28 ... irradiation surfaces 30a, 30b, 31a, 31b ... light emitting area 32 ... boundary 33 ... Shading means

Claims (2)

The ring-shaped light guide (13) in which the ring-shaped light emitting part (12) is formed, and the illumination light diffuser (14) attached to the light emitting part (12),
In the ring-shaped light guide (13), the light emitting part (12) is equiangularly divided into a plurality of light emitting parts (17a, 17b, 18a, 18b), and each light emitting part (17a, 17b, 18a, 18b). The ring-shaped light emitting portion (12) is formed so as to be capable of partially emitting light by emitting light every two or more light emitting portions,
The illumination light diffuser (14)
It is formed of a truncated conical cylindrical light guide (24) that expands from one end side toward the other end side,
A light introducing part (25) for introducing light emitted from the light emitting part (12) of the ring-shaped light guide (13) is formed on the one end side,
The inner surface of the outer peripheral surface (26) and the other end surface (27) is formed of a reflecting surface that reflects the light traveling in the light guide (24) to the inner side,
An irradiation surface (28) for diffusing and irradiating light traveling in the light guide (24) into a space surrounded by the light guide (24) is formed on the inner peripheral surface,
The irradiation surface (28) has a plurality of light emitting regions (30a, 30b, 31a, 31b), and a light shielding means (33) for blocking light traveling through the light guide (24) toward the other light emitting region at the boundary (32) between the adjacent light emitting regions. A lighting device comprising: The ring-shaped light emitting part (12) is equiangularly divided into a plurality of light emitting parts (17a, 17b, 18a, 18b), and each light emitting part (17a, 17b, 18a, 18b) or two or more light emitting parts. An illumination light diffuser attached to the light emitting part (12) of a ring-shaped light guide (13) capable of emitting light partially by emitting light for each part. ,
It is formed of a truncated conical cylindrical light guide (24) that expands from one end side toward the other end side,
A light introducing part (25) for introducing light emitted from the light emitting part (12) of the ring-shaped light guide (13) is formed on the one end side,
The inner surface of the outer peripheral surface (26) and the other end surface (27) is formed of a reflecting surface that reflects the light traveling in the light guide (24) to the inner side,
An irradiation surface (28) for diffusing and irradiating light traveling in the light guide (24) into a space surrounded by the light guide (24) is formed on the inner peripheral surface,
The irradiation surface (28) has a plurality of light emitting regions (30a, 30b, 31a, 31b), and a light shielding means (33) for blocking light traveling through the light guide (24) toward the other light emitting region at the boundary (32) between the adjacent light emitting regions. An illumination light diffuser characterized by comprising:

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