JP2005009990A - Imaging system for headlight tester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exclude the effects of halation in the case of measuring an irradiation beam of a headlight. <P>SOLUTION: This imaging system of a headlight tester 10 has a screen 14 for forming an image of the irradiation beam from a condenser lens 11. At least the back surface of the screen 14 is frosted. Imaging data on the irradiation beam I is collected from the back surface side by a CCD camera 16. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention generally relates to a headlight tester, and more particularly to an imaging system that captures an image of an irradiation beam to measure the irradiation beam of the headlight used in the headlight tester. is there.
[0002]
[Prior art]
The headlight tester has a measurement optical system for measuring the irradiation beam in order to inspect the state of the irradiation beam irradiated from the headlight of a vehicle such as an automobile. An example of a conventional headlight tester having such a measurement optical system is shown in FIG. That is, the headlight tester 1 has a substantially box-shaped housing 6, and the Fresnel lens 3 is provided in the front opening of the housing 6. The irradiation beam I from the headlight 2 positioned at a predetermined position in front of the headlight tester 1 is imaged on the screen 4 positioned in the housing 6 by the Fresnel lens 3. The image of the irradiation beam I formed on the screen 4 is picked up by the CCD camera 5 located at a predetermined position in front of the screen 4 in the housing 6. Then, the image data from the CCD camera 5 is sent to an image processing apparatus (not shown) constituted by, for example, a CPU, and image analysis is performed to determine the state of the irradiation beam I. Such an image processing apparatus can be provided in the headlight tester 1, but can also be a separate apparatus connected to the headlight tester 1.
[0003]
In the conventional example shown in FIG. 1, the CCD camera 5 is positioned obliquely in front of the screen 4. However, as another conventional example, the CCD camera 5 is positioned diagonally in front of the screen 4. It is also possible to position it at a position symmetrical with respect to the optical axis of the irradiation beam I).
[0004]
In the imaging system in the conventional headlight tester as described above, the CCD camera 5 is arranged in front of the screen 4 and images the light distribution state of the irradiation beam I imaged on the screen 4. Since the illuminance of the irradiation beam I is usually relatively high, the imaging data obtained by the CCD camera 5 due to the halation is not necessarily reliable, and the image of the irradiation beam I imaged on the screen 4 There was a difficulty in accurately capturing the image.
[0005]
Further, the housing 6 of the headlight tester 1 is usually provided with an external screen 7 for visual confirmation by an operator, and the irradiation beam I is irradiated onto the external screen 7 from the screen 4 via the reflection optical system. An image is formed. Therefore, in order for the image formed on the external screen 7 to be sufficiently bright, the front surface of the screen 4 is required to have a relatively high reflectivity. The reflected irradiation beam I tends to have a high halation, which tends to make the imaging operation by the CCD camera 5 difficult.
[0006]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and an object of the present invention is to provide an imaging system for a headlight tester that solves the above-described drawbacks of the prior art and is improved. Another object of the present invention is to provide an imaging system for a headlight tester in which the influence is reduced or substantially eliminated by halation of an irradiation beam from the headlight.
[0007]
[Means for Solving the Problems]
According to the present invention, in an imaging system for a headlight tester,
A condensing lens that receives the irradiation beam from the headlight,
A screen that is at least partially transparent and that is at least partially matted on its back to image the illumination beam by the condenser lens;
An imaging device that captures an image of the irradiation beam imaged on the screen from a back side of the screen;
An imaging system for a headlight tester is provided.
[0008]
Preferably, at least a portion on the back side corresponding to a portion of the screen on which the irradiation beam is imaged is subjected to a matt treatment.
[0009]
More preferably, the screen is a glass plate, and at least a predetermined area on the back surface of the glass plate is ground glass.
[0010]
More preferably, the screen is a resin plate, and at least a predetermined area on the back surface of the resin plate is matted.
[0011]
More preferably, the matting treatment is performed by applying a matte coating to the back side portion of the screen.
[0012]
More preferably, the imaging device includes a CCD camera. More preferably, the condensing lens is a Fresnel lens.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
A headlight tester 10 incorporating an imaging system according to one embodiment of the present invention is shown in FIG. That is, the headlight tester 10 has a generally box-shaped housing 17, and a condensing lens 11 such as a Fresnel lens is attached to the front opening thereof. The condenser lens 11 is positioned so as to receive the irradiation beam I emitted from the headlight 2 for a vehicle such as an automobile located at a predetermined position in front of the headlight tester 10. Therefore, the headlight tester 10 is supported so as to be movable in the left-right direction with respect to the automobile positioned in front of the headlight tester 10 and movable in the vertical direction. The headlight tester 10 is mounted on a support device capable of moving the headlight tester 10 in the vertical and horizontal directions so that the optical axis is locked at a predetermined position. Further, such a support device may be configured to support the headlight tester 10 so as to be movable in the front-rear direction so that the headlight tester 10 is positioned close to and away from the headlight 2.
[0014]
The irradiation lens I is imaged on the screen 14 via the half mirror 12 by the condenser lens 11. Therefore, the screen 14 is located at a distance that allows the irradiation beam I to be imaged from the condenser lens 11. The screen 11 is positioned substantially perpendicular to the optical axis 18 of the condenser lens 11, and a half mirror 12 inclined at a predetermined angle with respect to the optical axis 18 is disposed in front of the screen 11. Yes. The half mirror 12 is configured to reflect a part of the irradiation beam I from the condenser lens 11 to form an image on the external screen 13 so that the operator can confirm the irradiation beam I by visual observation. .
[0015]
On the other hand, the remainder of the irradiation beam I transmitted through the half screen 12 forms an image of the irradiation beam I on the front surface of the screen 14. The screen 14 is made of at least partially transparent material, and at least the back side thereof is matted. For example, when the screen 14 is made of a glass plate, the back side thereof can be ground glass (for example, by sandblasting). On the other hand, when the screen 14 is made of a resin plate, the back side thereof can be matted by performing a matting process. Furthermore, when the screen 14 is formed in a plate shape from, for example, glass, resin, or other appropriate at least partially transparent substances, a paint having a large or small particle size is applied to the back side thereof. It is possible to perform a matte treatment by applying a matte coating. Furthermore, as another embodiment, it is possible to perform a matting process on both sides of the screen 14. Note that when the matte process is performed on the screen 14, for example, it may be configured to be performed not only on the entire rear surface but only on a predetermined area where the irradiation beam I is imaged.
[0016]
In the embodiment shown in FIG. 2, the reflection mirror 15 is arranged at a predetermined position on the rear side of the screen 4 at an angle of about 45 degrees with respect to the optical axis 18, and further above the reflection mirror 15. An imaging device 16 such as a CCD camera is disposed in the camera. Therefore, the imaging device 16 can image the irradiation beam I imaged on the screen 14 from the back side of the screen 14. When the imaging device 16 is arranged on the optical axis 18 behind the screen 14, the reflection mirror 15 can be removed.
[0017]
The imaging data collected by the imaging device 16 is supplied to, for example, an image processing device (not shown) configured by a CPU or the like provided in the headlight tester 10, and the image processing device performs image processing on the imaging data. The state of the irradiation beam I can be determined. Note that such an image processing apparatus can be configured separately from the headlight tester 10 and can receive image data from the headlight tester 10 via wiring.
[0018]
As described above, in the embodiment shown in FIG. 2, at least a predetermined area on the back side of the screen 14 (for example, an area where the irradiation beam I is imaged) is a frosted area. It is possible to avoid or reduce the influence of halation when taking an image imaged on 14. In particular, there are various types of headlights 2 and those with various luminosities. According to the present invention, at least a predetermined area on the back side of the screen 4 is frosted, so that it is substantially affected by halation. It is possible to perform the imaging process accurately and reliably without any trouble.
[0019]
Further, when the imaging device 16 has a shutter structure, it is possible to incidentally respond to a change in illuminance of the irradiation beam I by changing the shutter speed. Further, when the imaging device 16 has a diaphragm mechanism, it is possible to incidentally respond to a change in illuminance of the irradiation beam I by appropriately adjusting the diaphragm mechanism.
[0020]
The embodiment shown in FIG. 3 is a modification of the embodiment of FIG. 2, in which two screens 14 are arranged in parallel along the optical axis 18. In this case, it is desirable that at least one screen 14 be detachable. By doing so, when the illuminance of the irradiation beam I from the headlight 2 to be inspected is high, two screens 14 are used, while when the illuminance of the irradiation beam I is not so high, one screen is used. Only the screen 14 can be used, and even when the illuminance of the irradiation beam I of the headlight 2 changes greatly, it is possible to appropriately cope with it. Therefore, as a further modification of the embodiment of FIG. 3, a desired number of screens 14 can be arranged along the optical axis 18, and any number of the screens 14 can be detachably attached. Is possible.
[0021]
As the imaging device 16, it is desirable to use a CCD camera, but it is also possible to use another camera having the same function as the CCD camera.
[0022]
【The invention's effect】
According to the present invention, even when the illuminance of the irradiation beam of the headlight is high, it is possible to collect imaging data of the irradiation beam accurately and reliably. Furthermore, according to the present invention, it is possible to improve the performance of the headlight tester with a relatively simple structure and without requiring a large installation space.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a conventional headlight tester.
FIG. 2 is a schematic diagram showing a headlight tester incorporating an imaging system according to an embodiment of the present invention.
FIG. 3 is a schematic view showing a modification of the present invention.

Claims (7)

In the imaging system for headlight testers,
A condensing lens that receives the irradiation beam from the headlight,
A screen that is at least partially transparent and that is at least partially matted on its back to image the illumination beam by the condenser lens;
An imaging device that captures an image of the irradiation beam imaged on the screen from a back side of the screen;
An imaging system for a headlight tester characterized by comprising: 2. The imaging system for a headlight tester according to claim 1, wherein at least a portion on the back side corresponding to the portion of the screen on which the irradiation beam is imaged is subjected to a matte process. The imaging system for a headlight tester according to claim 1, wherein the screen is a glass plate, and at least a predetermined area on the back surface of the glass plate is ground glass. 3. The imaging system for a headlight tester according to claim 1, wherein the screen is a resin plate, and at least a predetermined area on the back surface of the resin plate is matted. 3. The imaging system for a headlight tester according to claim 1, wherein the matting process is performed by applying a matte coating to the back side portion of the screen. 6. The imaging system for a headlight tester according to claim 1, wherein the imaging device includes a CCD camera. The imaging system for a headlight tester according to claim 1, wherein the condenser lens is a Fresnel lens.

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