Line scan camera lighting device

Abstract

To provide an illumination device for a line scan camera which has a plurality of irradiation angles, can electronically control a blend ratio of each illumination light source, minimizes an influence of variation on workpiece surface of an imaging object or surface roughness, facilitates setting of an illumination condition, dispenses with know-how of setting of an illumination device, can reduce cost, and has a plurality of illuminations arranged at optimum positions.SOLUTION: An illumination device for a line scan camera includes: a line scan camera 3 for imaging an imaging object 2 from above; a first illumination light source 4 arranged on one side part; second illumination light sources 7 arranged on both side parts; an illumination angle adjustment part 8 which is made of a material that can adjust an illumination angle so as to condense the light from the first illumination light source 4 to the imaging object 2, and can transmit a line scan signal from the line scan camera 3; and a reflecting plate 9 for performing adjustment so as to irradiate the imaging object 2 with the light from the second illumination light source 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an illumination device for use in a line scan camera. [Background technology]

[0002] Currently, line scan cameras are being introduced in the manufacturing industry for purposes such as automated inspection and quality control of products and pharmaceuticals, and for the purpose of improving the efficiency of monitoring and management of production facilities. A line scan camera is a camera that captures images of a line, unlike an area camera that captures images of a surface of the object. Line scan cameras are characterized by their ability to capture high-quality images, but they require a short exposure time and a bright imaging environment.

[0003] Therefore, when performing visual inspections using image processing with a line scan camera, it is necessary to optimize the lighting environment; however, in actual visual inspections, general-purpose, single-function lighting environments are currently used.

[0004] As a result, there were issues such as: (1) defects may not be made visible if lighting is only in a limited irradiation direction; (2) in cases such as (1), it is necessary to prepare and try multiple different lights or combine multiple lights as necessary; (3) it is easily affected by variations in the workpiece surface and surface roughness; (4) lighting conditions cannot be set electronically, and know-how is required for setting them up; (5) the cost of combining single-function lights is very high; (6) there are cases where lighting interferes with each other and it is not possible to place lighting in the optimal position due to composition; and (7) lighting suitable for line scan cameras, which require particularly high brightness, has a limited irradiation angle, making the issues above (2) to (4) particularly pronounced.

[0005] In order to solve the above problems, there is a demand for a high-performance hybrid lighting device that has multiple illumination angles, can electronically control the blending ratio of each lighting, and can be used with a line scan camera. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2006-266952 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above-mentioned conventional demands, and has an object to provide an illumination device for a line scan camera which has multiple illumination angles, can electronically control the blending ratio of each illumination light source, minimizes the effects of variations or surface roughness on the work surface of the object to be imaged, makes it easy to set illumination conditions, does not require know-how for setting the illumination device, and can reduce costs, thereby providing an illumination device in which multiple illumination devices are arranged in optimal positions. [Means for solving the problem]

[0008] The present invention relates to A line scan camera that captures an image of an object from above; a first illumination light source disposed on one side of a gap between the line scan camera and the image capture target; A second illumination light source is disposed on both sides of a gap between the first illumination light source and the image capture target; an illumination angle adjustment unit that is provided between the line scan camera and the image capture object, the illumination angle adjustment unit being capable of adjusting an illumination angle so as to focus light from the first illumination light source on the image capture object, and that is made of a material that allows a line scan signal from the line scan camera to pass through; A reflector that adjusts the light from the second illumination light source so as to irradiate the image capture target. It is characterized by: or The irradiation angle adjustment unit is formed of a half mirror made of a material through which a line scan signal from the line scan camera can pass. It is characterized by: or The first illumination light source is composed of a high-angle illumination light source and a coaxial epi-illumination light source. It is characterized by the above. Effect of the Invention

[0009] The lighting device for line scan cameras according to the present invention has multiple illumination angles, can electronically control the blending ratio of each lighting light source, minimizes the effects of variations or surface roughness on the work surface of the object to be imaged, makes it easy to set lighting conditions, does not require know-how for setting the lighting device, reduces costs, and provides other excellent effects such as multiple lighting devices being positioned in optimal positions. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram (1) of the configuration of an illumination device for a line scan camera according to the present invention. [Diagram 2] FIG. 2 is an explanatory diagram (2) of the configuration of an illumination device for a line scan camera according to the present invention. [Diagram 3] FIG. 3 is an explanatory diagram of the configuration of an illumination device for a line scan camera according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of an illumination device 1 for a line scan camera according to the present invention, and FIG. 2 is a perspective view of the illumination device 1 for a line scan camera.

[0012] First, the basic configuration of the illumination device 1 for a line scan camera will be described. Reference numeral 3 in Fig. 1 denotes a line scan camera. The line scan camera 3 captures an image of an object 2 to be imaged from above along a line, and stitches together the images captured along the line to form a single image.

[0013] A first illumination light source 4 is disposed on one side of the gap between the line scan camera 3 and the image capture target 2. The first illumination light source 4 is constituted by a high-angle illumination light source 5 and a coaxial epi-illumination light source 6. As can be seen from FIG. 2, the high-angle illumination light source 5 and the coaxial epi-illumination light source 6 are formed by arranging a plurality of illumination light sources, such as LEDs, side by side in the horizontal direction. The first illumination light source 4 in the present invention is constituted by two high-angle illumination light sources 5 and a coaxial epi-illumination light source 6 disposed between the high-angle illumination light sources 5, 5. The number of high-angle illumination light sources 5 and coaxial epi-illumination light sources 6 constituting the first illumination light source 4 is not limited in any way.

[0014] 1 and 2, second illumination light sources 7 are disposed on both sides of the gap between the first illumination light source 4 and the image capture object 2. As the second illumination light source 7, for example, a side illumination light source is used, and similar to the high-angle illumination light source 5 and the coaxial epi-illumination light source 6, a plurality of illumination light sources such as LEDs are disposed in the horizontal direction.

[0015] Here, the characteristics of the various illumination light sources will be briefly described. The high-angle illumination light source 5 has the characteristic that it reflects less light from a flattened surface (insufficient brightness) and the construct between the uneven and flat portions is smaller than that of the coaxial epi-illumination light source 6. The coaxial epi-illumination light source 6 is characterized in that a surface that has been flattened neatly is imaged bright (sufficient brightness) and an uneven surface is imaged dark, so the construct between the flat and uneven portions is larger. The side illumination light source is characterized in that the surface is imaged dark (insufficient brightness) and there is a lot of reflected light from the uneven portions, so the construct between the uneven and flat portions is larger.

[0016] Therefore, by taking advantage of the characteristics of the high-angle illumination light source 5 of the first illumination light source 4, the coaxial incident illumination light source 6, and the side illumination light source of the second illumination light source 7, and blending the light from the first illumination light source 4 and the second illumination light source 7, it is possible to flexibly and clearly image the object to be imaged 2 while minimizing the effects of surface variation or surface roughness of the object to be imaged 2.

[0017] In addition, the luminance of the first illumination light source 4 and the second illumination light source 7 can be electronically controlled independently by controlling the blend ratio of each illumination light source, which makes it easy to set the illumination conditions and eliminates the need for know-how on the settings of each illumination light source.

[0018] In the illumination device for line scan camera 1 of the present invention, an illumination angle adjustment unit 8 is provided between the line scan camera 3 and the object to be imaged 2 in order to focus the light emitted by the high-angle illumination light source 5 and the coaxial epi-illumination light source 6 constituting the first illumination light source 4 onto the object to be imaged 2. The illumination angle adjustment unit 8 has a rectangular plate shape and is formed of a half mirror made of a material that allows the line scan signal from the line scan camera 3 to pass through. The illumination angle adjustment unit 8 is configured so that the angle of the illumination angle adjustment unit 8 can be freely changed so that the illumination angle of the emitted light can be adjusted.

[0019] 1 and 2, reflectors 9, 9 are provided on both sides of the gap between the irradiation angle adjustment unit 8 and the image capture object 2. The reflector 9 has a rectangular plate shape, and the surface of the rectangular plate-shaped reflector 9 is mirror-finished. Therefore, the optical path can be changed so that the light emitted by the second illumination light source 7 is irradiated onto the image capture object 2, and the angle of the second illumination light source 7 can be freely changed manually, so that the focal distance to the image capture object 2 can be changed.

[0020] Next, an embodiment in which a diffusion plate 10 and a condenser lens 11, which will be described later, are provided in addition to the basic configuration of the illumination device 1 for a line scan camera will be described. 3, a rectangular diffuser plate 10 is provided between the first illumination light source 4 and the irradiation angle adjustment unit 8. The diffuser plate 10 is also provided between the second illumination light source 7 and the reflector 9. Therefore, the light emitted from the first illumination light source 4 and the second illumination light source 7 is configured to pass through the diffuser plate 10. The diffuser plate 10 is provided to diffuse light concentrated in a specific direction to make the light uniform.

[0021] A rectangular plate-shaped condenser lens 11 is provided between the first illumination light source 4 and the second illumination light source 7 and the diffusion plate 10 for each of the first illumination light source 4 and the second illumination light source 7. The condenser lens 11 may be a lens that condenses light, such as a linear Fresnel lens or a Fresnel lens array. By providing the condenser lens 11, attenuation of light from the first illumination light source 4 and the second illumination light source 7 can be prevented, and the directivity of the optical path can be maintained.

[0022] Next, an embodiment using the illumination device for line scan cameras 1 of the present invention will be briefly described. The angle (tilt) of the irradiation angle adjusting unit 8 is adjusted so that the light from the first illumination light source 4 is irradiated onto the image capture target 2. Then, the angle (tilt) of the reflecting plate 9 is adjusted so that the light from the second illumination light source 7 is also irradiated onto the image capture target 2 in the same manner.

[0023] Here, since the irradiation angle adjustment unit 8 and the reflector 9 are configured so as to be freely adjustable manually, the focal distance to the image capture object 2 can be easily changed.

[0024] As described above, the condenser lens 11 is provided to prevent the light from the first illumination light source 4 and the second illumination light source 7 from being attenuated, and the light can be irradiated while maintaining the directivity of the optical path. Then, with the directivity of the optical path maintained by the condenser lens 11, the light can be diffused by passing through the diffusion plate 10 to make the light uniform.

[0025] This allows light to be uniformly irradiated onto the irradiation angle adjustment unit 8 and the reflector 9, and the image capture target 2 can be irradiated with light while making the most of the characteristics of the first illumination light source 4 and the second illumination light source 7. In addition, the luminance of the first illumination light source 4 and the second illumination light source 7 is configured so that the blend ratio of each illumination light source can be electronically controlled independently. The line scan camera 3 can capture a clear and flexible image of the object 2 from above.

[0026] Therefore, the lighting device 1 for line scan cameras of the present invention can provide a lighting device that can create an environment in which even a person with little knowledge about lighting can easily capture the desired images, which was not possible with existing lighting. [Explanation of symbols]

[0027] 1. Illumination device for line scan camera 2. Image capture target 3. Line scan camera 4 First illumination light source 5 High-angle illumination source 6 Coaxial epi-illumination light source 7 Second illumination light source 8 Irradiation angle adjustment section 9 Reflector 10 Diffuser 11 Condenser lens

Claims

1. A line scan camera that captures an image of an object from above; a first illumination light source disposed on one side of a gap between the line scan camera and the image capture target; A second illumination light source is disposed on both sides of a gap between the first illumination light source and the image capture target; a plate-shaped illumination angle adjustment unit provided between the line scan camera and the imaged object, capable of adjusting an illumination angle so as to focus light from the first illumination light source on the imaged object, and made of a material through which a line scan signal from the line scan camera can pass; a reflector that adjusts the light from the second illumination light source so as to irradiate the image capture target, The first illumination light source is composed of a high-angle illumination light source and a coaxial epi-illumination light source, and light from the high-angle illumination light source and the coaxial epi-illumination light source is reflected from the illumination angle adjustment unit at angles different from each other to illuminate the imaging object.

1. An illumination device for a line scan camera.

2. The irradiation angle adjustment unit is formed of a half mirror made of a material through which a line scan signal from the line scan camera can pass.

2. The illumination device for a line scan camera according to claim 1.

3. a diffusion plate is provided between the first illumination light source and the irradiation angle adjustment unit and between the second illumination light source and the reflector, a condenser lens is provided between the first illumination light source and the diffusion plate and between the second illumination light source and the diffusion plate; 3. The illumination device for a line scan camera according to claim 1 or 2.

Images