JPH047939B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method and device for inspecting the optical axis of a headlamp, and in particular, to a method for inspecting the optical axis of a headlamp of an automobile, and particularly for checking whether the center position of the optical axis of an automobile headlamp is within the standard value range. The present invention relates to a headlamp optical axis inspection method and apparatus suitable for inspecting the headlamp.

[Conventional technology]

2. Description of the Related Art Conventionally, when inspecting the optical axis of a headlamp in an automobile inspection factory, a headlamp tester 10 as shown in FIG. 5 has been used. This tester 10 has four light receiving elements 14a, 14b, 14c, and 14d around a lens 12. When testing using this tester 10, the tester 10 is moved to a position where the irradiated light from the headlamp 16 is received, the amount of light received by each light receiving element is constant, and the optical image by the irradiated light from the headlamp 16 is transferred to the lens 12. The image was projected onto a screen via a 300-degree brightness filter, and inspection was performed using the highest illuminance point on the screen as the optical axis.

However, when a halogen headlamp is used as the headlamp 16, as shown in FIG. 6, there are two maximum illuminance points, so the position of the optical axis is the maximum illuminance point L ₁ and the maximum illuminance point L _{2 .} It is on the straight line L connecting the two lines, and there is a problem that it cannot be unambiguously determined.

Therefore, the applicant of the present application determined the height position of the headlamp by detecting the direct light of the headlamp, as described in Japanese Patent Application Laid-Open No. 179639/1982, and conducted a main optical axis inspection from this headlamp height position. Find a window that shows the acceptable range of the test, display this window as an image on a display device, and then find the center of gravity of an isoluminant closed curved surface with a certain illuminance or more from the light distribution pattern of the headlamp on a screen installed in front of the vehicle. The present invention has proposed an apparatus in which an image is displayed on the display device and the position of the headlamp is adjusted so that the center of gravity of the isoluminant closed surface is within the window. According to this method, even if the highest illuminance points occur at two locations, such as in the case of a halogen headlamp, the optical axis position of the headlamp can be displayed as an image at one point.

[Problem that the invention seeks to solve]

However, in the method previously filed by the applicant, when determining the optical axis position of the headlamp, a method was adopted to determine the center of gravity of the entire light distribution pattern. When two isoluminant closed curved surfaces 20, 22 are formed, these isoluminant closed curved surfaces 20,
The geometric center position of 22, that is, the center of gravity position is code 2
Since the center of gravity position 24 is displayed as a position indicated by 4, which is different from the actual bright place, there is a possibility that the optical axis of the headlamp cannot be detected accurately.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to accurately measure the optical axis position of a headlamp even when a plurality of isoluminant closed curved surfaces are formed in the light distribution pattern of the headlamp. An object of the present invention is to provide a method and apparatus for inspecting the optical axis of a headlamp.

[Means for solving problems]

In order to achieve the above object, the present invention, as shown in FIG. 1, selects and images a light distribution pattern of equal illuminance from among the light distribution patterns on the screen caused by the irradiation light of the headlamp (step 100). ,
The captured image is displayed on the CRT screen (step 102), and the acceptable range of the optical axis of the headlamp is displayed on the CRT screen (step 1).
04), find the center of gravity of the isoluminant closed surface within a specific area of the light distribution pattern (step 106),
This center of gravity position is displayed on the CRT screen (step 108), and the optical axis of the headlamp is inspected by displaying this center of gravity position. A television camera that selects and captures an equiluminous light distribution pattern from the light distribution pattern of the light image on the screen, and converts the video signal into image data from the composite video signal output from the television camera and stores it. A memory section, a display section that receives a composite video signal and displays an image on a CRT screen, a standard value setting section that outputs a standard value indicating the acceptable range of the optical axis of the headlamp as image data, and a CRT
A window command unit that commands a specific area of the screen using image data, a window unit that imports a group of image data corresponding to the specific area from the memory unit according to the window command, and a window unit that uses the image data group that is imported into the window unit. , a center of gravity calculation unit that calculates the center of gravity of the isoluminant closed surface of the area corresponding to these data groups and outputs the calculated value as image data; and converts each of the image data into a video signal;
The apparatus further includes a composite video signal generating section that converts this signal into a composite video signal and outputs the signal.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 2 shows the configuration of a preferred embodiment of the invention. In FIG. 2, a translucent screen 32 is movably installed on the vehicle inspection line to project an optical image produced by the light emitted from the headlamp 30. An inspection table 36 is installed on the opposite side of the vehicle 34 with the screen 32 as a border, and a television camera mounting stand 3 is mounted on this inspection table 36.
8 is fixed so as to be movable in the horizontal direction. A support stand 40 is attached to the television camera mount 38 so as to be movable up and down, and an industrial television camera 42 is fixed to the support stand 40. Further, a control device 44 is fixed on the examination table 36, and a CRT 48 and an operation section 50 for outputting various settings and command values by operating operation buttons are arranged on the front panel 46 of the control device 44. There is.

The television camera 42 is configured to image the light distribution pattern 52 on the screen 32 and output a composite video signal resulting from this image to the control device 44 . When imaging this light distribution pattern, by adjusting the lens diaphragm 54, it is possible to select and image a light distribution pattern with equal illuminance from among the light distribution patterns.

The control device 44, as shown in FIG.
CPU 60, A/D converter 6 that constitutes the memory section
2, a frame memory 64, a window circuit 66 as a window section, a center of gravity calculation circuit 68 as a center of gravity position calculation section, a standard data memory 70, a video RAM 72 constituting a composite video signal generation section, a switch 74, an output data controller 76, an I /O
Port 78, CRT48 and CRT that make up the display section
It has a controller 80, etc., and is connected to an output data controller 76, a frame memory 64, a center of gravity calculation circuit 68, etc. via a bus line 82.

Composite video signal S ₁ output from the television camera 42
is the CRT controller 80 via the switch 74.
and is also supplied to the A/D converter 62. Therefore, the image captured by the television camera 42 is displayed on the screen of the CRT 48, and the video signal of the composite video signal _S1 is converted into a digital signal by the A/D converter 62 and stored as image data in the frame memory 64. be done. Among the image data stored in the frame memory 64, the image data specified by the window command is output to the window circuit 66. That is, when a window command is given to the window circuit 66 via the I/O port 78 by operating the operation button constituting the window command section, the frame memory 64
Image data of a specific area of the image displayed on the screen of the CRT 48 is taken into the window circuit 66. When image data is taken into this window circuit 66, the CPU
In response to the command 60, these image data groups are supplied to the center of gravity calculation circuit 68, and the center of gravity position of the isoluminant closed surface (hot zone) in the specific area is calculated.

To find this center of gravity position, calculate the sum of position vectors Σ(X _y・Y _y ) and area S of the hot zone, and from this calculate the center of gravity position G (X, Y).
Obtain as (X, Y)=Σ(X _i ·Y _i )/S. This center of gravity position G (X, Y) is sent as image data to the video RAM 72 via the output data controller 76.
is stored in

In addition, in order to set the standard value indicating the acceptable range of the optical axis of the headlamp 30, the standard value data is changed to
The data is stored in the standard value data memory 70 via the O port 78. This standard value data is stored in the video RAM 72 as image data according to a command from the output data controller 76. Further, the image data stored in the frame memory 64 is also stored in the video RAM 72 as image data according to a command from the output data controller 76.

Various image data stored in the video RAM 72 is converted into a video signal and combined with a horizontal synchronization signal and a vertical synchronization signal. Then, the composite video signal _S2 is sent to the CRT controller 8 via the switch 74.
Output to 0.

In the above configuration, the switch 74 is operated to output the output signal of the television camera 42 directly to the CRT controller 80, the screen 32 is moved to a position out of the imaging range of the television camera 42, and the head lamp 30 is turned off. The image taken by the television camera 42 is displayed on the screen of the CRT 48. In this state, TV camera 4
The television camera 42 is moved so that the origin P of No. 2 overlaps the center Q of the headlamp 30.

Next, the switch 74 is operated to the opposite side, the screen 32 is set between the television camera 42 and the headlamp 30, the headlamp 30 is turned on, and the light distribution pattern 52 of the light irradiated by the headlamp 30 is projected on the screen 32. When this light distribution pattern 52 is imaged with the television camera 42,
Video signals obtained by imaging are sequentially stored in the frame memory 64 as image data. These image data are sequentially stored in the video RAM 72, and the video output from the video RAM 72 is displayed on the screen of the CRT 48. Here, the examiner
When adjusting the lens aperture 54 while looking at the binarized image displayed on the screen of 8, as shown in _FIG .
Z ₂ can be displayed on the CRT48 screen.

Next, when you perform an operation to command a specific area (window) _W1 on the CRT48 screen with image data,
This window command is given to the window circuit 66 via the I/O port 78, and a group of image data corresponding to a specific area indicated by the window command among the image data in the frame memory 64 is taken into the window circuit 66. , the center of gravity position of the isoluminant closed surface (hot zone) of window _W1 is calculated by the center of gravity calculation circuit 68. That is, when the area surrounding hot zone Z 2 out of hot zones Z _{1 and} Z ₂ is designated as window W ₁ , the center of gravity position of hot zone Z ₂ is calculated. This calculated value is then stored in the video RAM as image data.
72 and converted into a composite video signal.
An image is displayed as an optical axis 84 on the screen of the CRT 48.

In addition, the head lamp 30 can be turned on by operating the operation button.
When a standard value indicating the acceptable range of the optical axis is set, this standard value data is stored in the standard value data memory 70 via the I/O port 78, and is output as video data as image data by a command from the output data controller 76.
It is stored in RAM72. Then, the image data is converted into a composite video signal, and an image showing a substantially rectangular standard range 86 is displayed on the screen of the CRT 48. Therefore, the inspector must ensure that the optical axis 84 is within the standard range 86.
The pass/fail of the optical axis inspection of the headlamp 30 can be determined based on whether or not it is displayed within the range. That is,
In this embodiment, since the center of gravity of the hot zone Z ₂ is set as the optical axis 84, the optical axis 84 is within the standard range 86.
The pass/fail of the optical axis inspection can be determined based on whether or not it is displayed within the range. Note that when the inspector selects the center of gravity position of the hot zone Z ₁ as the optical axis, it is possible to judge whether or not the optical axis inspection is successful based on whether the optical axis of the hot zone Z ₁ is displayed within the standard range 86. .

In this way, in this embodiment, when a plurality of hot zones are formed in the light distribution pattern, the optical axis of each hot zone is determined. The optical axis of the can be quantitatively measured.

Furthermore, according to this embodiment, the optical axis of the headlamp can be inspected with a single television camera.
It can be constructed at a lower cost than the one previously proposed by the applicant.

〔Effect of the invention〕

As explained above, according to the present invention, when a plurality of hot zones are formed in the light distribution pattern by the irradiation light of the headlamp, the center of gravity of one hot zone is determined as the optical axis. Even when a hot zone is formed, an excellent effect can be obtained in that the optical axis of the headlamp can be accurately inspected.

[Brief explanation of drawings]

FIG. 1 is a flowchart for explaining the present invention, FIG. 2 is an overall configuration diagram of a device to which the present invention is applied, and FIG. 3 is a specific configuration diagram of the device according to the present invention.
FIG. 4 is a diagram showing an example of image display by the device according to the present invention, FIG. 5 is a perspective view of a conventional headlamp tester, FIG. 6 is a diagram showing an example of image display by the conventional device, and FIG. 7 is a diagram of the conventional headlamp tester. FIG. 7 is a diagram showing an example of image display by another device. 30...head lamp, 32...screen,
42... Television camera, 44... Control device, 48
...CRT, 50...Operation unit, 60...CPU, 6
4... Frame memory, 66... Window circuit, 68... Center of gravity calculation circuit, 72... Video
RAM, 80...CRT controller.

Claims (1)

[Claims] 1. Select and image a light distribution pattern with equal illuminance from among the light distribution patterns on the screen caused by the light irradiated by the headlamp, and display this image on the CRT screen. Display the passing range on the CRT screen, find the center of gravity of the isoluminant closed surface within a specific area of the light distribution pattern,
A method and device for inspecting the optical axis of a headlamp, characterized in that the center of gravity position is displayed on a CRT screen, and the optical axis of the headlamp is inspected based on the display of the center of gravity position. 2. A screen that projects a light image from the light irradiated by the headlamp, a television camera that selects and captures an equiluminous light distribution pattern from the light image on the screen, and a composite video signal output from the television camera. A memory section that converts the video signal into image data and stores it, a display section that receives the composite video signal and displays the image on the CRT screen, and outputs the standard value indicating the acceptable range of the optical axis of the headlamp as image data. A standard value setting section, a window command section that commands a specific area of the CRT screen using image data, a window section that imports a group of image data corresponding to the specific area from the memory section according to the window command, and a window section that imports a group of image data corresponding to the specific area into the window section. A center of gravity calculation unit that calculates the center of gravity of an isoluminant closed surface of a region corresponding to the image data group and outputs the calculated value as image data; 1. An optical axis inspection device for a headlamp, comprising: a composite video signal generating section that converts the signal into a composite video signal, and further converts the signal into a composite video signal and outputs the composite video signal.