JPH047941B2 - - Google Patents

Description

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

[Conventional technology]

Conventionally, when inspecting the optical axis of a headlamp at an automobile inspection factory, a headlamp tester 10 as shown in FIG. 7 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. 8, there are two maximum illuminance points, so the position of the optical axis connects the maximum illuminance point L1 and the maximum illuminance point L2. This resulted in a problem that it could not be uniquely determined because it was on the straight line L.

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. A window indicating the acceptable range of the above is determined, this window is displayed as an image on a display device, the center of gravity position of the isoluminance closed curve with a certain illuminance or more is determined from the light distribution pattern of the headlamp on the screen installed in front of the vehicle, and the above-mentioned The proposed system displays an image on a display device and also adjusts the position of the headlamp so that the center of gravity of the isoluminous closed curve falls 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 to be solved by the invention]

However, in the method previously filed by the applicant, when determining the optical axis position of the headlamp, the center of gravity of the entire light distribution pattern was determined. When two isoluminant closed curved surfaces 20, 22 are formed, these isoluminant closed curved surfaces 20, 2
The geometric center position of 2, that is, the center of gravity position is 24
The center of gravity position 24 was displayed at a position different from the actual bright place, and the optical axis of the headlamp could not be accurately inspected in some cases.

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, sequentially images equal-intensity light distribution patterns among the light distribution patterns on the screen caused by the irradiation light of the headlamp according to the aperture value. (Step 200) The captured image is displayed on the CRT screen (Step 202), and the isoluminance closed curve of each light distribution pattern selected as the aperture value is extracted (Step 204).
The image displayed on the CRT is displayed as a traced waveform (step 206), and then the center of gravity of the area surrounded by each isoluminance closed curve is determined (step 2).
08), the process up to step 206 is repeated n times while changing the aperture to find the convergence value of the n barycenter positions (step 210), and this convergence value is displayed on the CRT screen as the optical axis ( Step 212), determine the acceptable range of the optical axis of the headlamp.
The optical axis of the headlamp is inspected by displaying these optical axes and the passing range on the CRT screen (step 214). A screen, a television camera that sequentially captures equiilluminance light distribution patterns according to the aperture value of the light distribution pattern of the light image on the screen, and a video signal of the composite video signal output from the television camera into image data. A memory section that converts and stores the image, a display section that receives the composite video signal and displays the image on a CRT screen, and a standard value setting section that outputs the standard value indicating the acceptable range of the optical axis of the headlamp as image data. The image data in the memory section is imported, and based on this image data, the isoluminance closed curves of each light distribution pattern are extracted, the barycenter position of the area surrounded by each isoluminance closed curve is determined, and the convergence value of these barycenter positions is calculated. an arithmetic unit that converts each of the image data into a video signal, further converts this signal into a composite video signal, and outputs the composite video signal. This is the configuration of the device.

〔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 from the screen 32.
A television camera mount 38 is fixed on the inspection table 36 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 this support stand 40. Also inspection table 36
A control device 44 is fixed above, and a display panel 46 of the control device 44 is provided with a CRT 48 and an operation section 50 that outputs various set values and command values by operating operation buttons.

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 calculation unit 66 that performs various calculations based on instructions from the CPU 60, a standard data memory 70, a video RAM 72 that constitutes a composite video signal generation unit, a switch 74, an output data controller 76, and an I/O port 78. , a CRT 48 and a CRT controller 80 that constitute a display section, an aperture controller 82 that instructs the lens aperture 54 to adjust the aperture, etc., and an output data controller 76, a frame memory 64, a calculation section 66, an aperture controller 82, etc. connected to the bus. They are connected by line 84.

Composite video signal S output from the television camera 42
1 is connected to the CRT controller 8 via the switch 74.
0 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
It is converted into a digital signal by the D converter 62 and stored in the frame memory 64 as image data. The image data stored in the frame memory 64 is sequentially outputted to the arithmetic unit 66 according to instructions from the CPU 60, and is also outputted to the video RAM 72 as binarized image data.

The calculation unit 66 includes an isoluminant closed curve extraction circuit 90, an isoluminant closed curve data memory 92, a center of gravity calculation circuit 94,
It is composed of a center of gravity data memory 96, a convergence point calculation circuit 98, and an optical axis data memory 100. The image data in the frame memory 64 is configured to be output to the isoluminant closed curve detection circuit 90, and the isoluminant closed curve extraction circuit 90 performs an isoluminant closed curve extraction operation based on the image data. In performing this extraction calculation, each image data is subjected to circumferential integration to extract the isoluminant closed curve, and when extracting the isoluminant closed curve, the area within the isoluminant closed curve is calculated. Processing is also done at the same time.

Also, when extracting this isoluminous closed curve, if the aperture value of the lens diaphragm 54 at that time is k, then
As shown in FIG. 4, the area S _NK (N=1, 2, . . . ) is determined for one closed curve L _NK .
The values of these isoluminant closed surfaces (hot zones) are stored as data in the isoluminant closed curve data memory 92.
The center of gravity calculation circuit 94 outputs the data to the center of gravity calculation circuit 94.

The center of gravity calculation circuit 94 calculates the sum of position vectors within the closed curve _LNK based on the data supplied from the isoluminance closed curve data memory 92, and divides this by the area value _SNK to calculate the center of gravity position G. _N.K.
= 1, 2...). This calculated value is then stored in the center of gravity data memory 96 and output to the convergence point calculation circuit 98. The center of gravity data memory 96 sequentially stores center of gravity calculation units corresponding to the aperture value k of the lens diaphragm 54, and as shown in FIG _. (N,K
=1, 2...) data is stored. The data stored as the barycenter point sequence data is sequentially output to the convergence point calculation circuit 98.

In the convergence point calculation circuit 98, the center of gravity data memory 9
The convergence value G _N =limG _NK (N=1, 2, . . . ) of each gravity center point sequence is determined based on the data of each gravity center point sequence supplied from 6, and this calculated value is output to the optical axis data memory 100. The optical axis data stored in the optical axis data memory 100 is stored as image data in the video RAM 72 according to a command from the output data controller 76. In addition, isoluminant closed curve data memory 9
The data in 2 is also sent to the video RAM 72 as image data according to a command from the output data controller 76.
stored within. In other words, the aperture value k is changed moment by moment.
For each of these, the trace results of the binarized image data stored in the frame memory 64 are stored in the video RAM.
72.

Further, in order to set the standard value indicating the acceptable range of the optical axis of the headlamp 30, when the operation button that constitutes the standard value setting section is operated, the standard value data is transmitted to the standard value via the I/O port 78. The data is stored in the data memory 70. This standard value data is then stored in the video RAM 72 as image data in response 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 80 via the switch 74.
Output to. The CRT controller 80 includes a video amplifier, a synchronizing signal separation circuit, a vertical deflection circuit, a horizontal deflection circuit, etc., and can display a signal on the screen of the CRT 48 in accordance with the composite video signal.

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 captured by the television camera 42 is displayed on the CRT screen 4.
8 on the screen. In this state, the television camera 42 is moved so that the origin P of the television camera 42 overlaps with the center Q of the headlamp 30.

Next, operate the switch 74 to the opposite side and move the screen 32 between the television camera 42 and the headlamp 30.
At the same time, the headlamp 30 is turned on and a light distribution pattern 52 produced by the light emitted from the headlamp 30 is projected on the screen 32. When this light distribution pattern 52 is imaged with the television camera 42, the video signals resulting from the 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
The video output from the RAM 72 is displayed on the CRT 48 screen.

Here, when the inspector commands aperture adjustment by operating the operation button while looking at the binarized image displayed on the screen of the CRT 48, the camera aperture 54 is activated by the command from the aperture controller 82. , the aperture value k of the lens aperture 54 is adjusted to an arbitrary value. When this aperture adjustment is performed, a plurality of light distribution patterns 102 corresponding to the aperture value k are displayed as images on the screen of the CRT 48, as shown in FIG. Image data is output from frame memory 64 to calculation section 66 . Then, in the calculation unit 66, the optical axis is calculated according to the barycentric point sequence based on these image data,
Optical axes 104 and 106 are displayed as images on the CRT 48.

Also, at this time, when a standard value indicating the acceptable range of the optical axis of the headlamp 30 is set by operating the operation button, this standard value data is stored in the standard value data memory 70 via the I/O port 78, and the output data The image data is stored in the video RAM 72 as image data according to a command from the controller 76 . This image data is then converted to a composite video signal and
An image showing a substantially rectangular standard range 108 is displayed on the screen 48. Therefore, the inspector can determine whether the optical axis inspection of the headlamp 30 has passed or failed based on whether the optical axes 104 and 106 are displayed within the standard range 108. That is, in this embodiment, even if there are two equiluminance closed curved surfaces (hot zones) as in a halogen head lamp, the optical axes 104 and 106 are determined based on the convergence value of the center point array of the light distribution pattern 102. This optical axis 104, 10
6 is displayed as an image, the optical axis 104,
The pass/fail of the optical axis inspection can be determined based on whether any one of 106 is displayed within the standard range 100. Further, in this embodiment, even when a plurality of hot zones are formed in the light distribution pattern 102, the optical axis of each hot zone can be determined, and the optical axis of the headlamp 30 can be quantitatively measured.

Furthermore, according to this embodiment, the optical axis inspection of the headlamp 30 can be performed with a single television camera, so it can be constructed at a lower cost and is easier to operate than the one previously proposed by the applicant. Therefore, optical axis inspection can be performed.

〔Effect of the invention〕

As explained above, according to the present invention, among the light distribution patterns on the screen caused by the light irradiated by the headlamp, images of equiluminous light distribution patterns are sequentially captured according to the aperture value, and the images of the light distribution patterns selected according to the aperture value are Extract the isoluminant closed curves of the light pattern, find the centroid position of the area surrounded by each isoluminant closed curve, find the convergence value of these centroid positions, and display this convergence value on the CRT screen as the optical axis. Therefore, even when a plurality of hot zones are formed in the light distribution pattern, 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 for explaining the closed curve calculation method of the device according to the present invention, FIG. 5 is a diagram for explaining the barycenter point sequence calculation method of the device according to the present invention, and FIG. 7 is a perspective view of a conventional headlamp tester, FIG. 8 is a diagram showing an example of image display by the conventional device, and FIG. 9 is a diagram showing an example of image display by another conventional device. FIG. 30...head lamp, 32...screen, 42
...TV camera, 44...control device, 48...CRT,
50...Operation unit, 60...CPU, 64...Frame memory, 66...Arithmetic unit, 72...Video RAM, 80
...CRT controller.

Claims (1)

[Claims] 1. Of the light distribution patterns on the screen caused by the light irradiated by the headlamp, images of equiluminance light distribution patterns are sequentially imaged according to the aperture value, and the images obtained by this imaging are
At the same time, the passing range of the optical axis of the headlamp is displayed on the CRT screen, and the isoluminance closed curve of each light distribution pattern selected by the aperture value is extracted, and the area surrounded by each isoluminance closed curve is displayed on the CRT screen. A headlamp characterized in that the position of the center of gravity of a region is determined, the convergence value of these center of gravity positions is determined, and this convergence value is displayed on a CRT screen as an optical axis, and the optical axis of the headlamp is inspected by displaying this optical axis. optical axis inspection method. 2. A screen that projects the light image of the light irradiated by the headlamp, a television camera that sequentially captures equiilluminance light distribution patterns from the light image on the screen according to the aperture value, and a composite image of the output of 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 a standard value that indicates the acceptable range of the optical axis of the headlamp. The standard value setting section that outputs data and the image data of the memory section are imported, and based on this image data, the isoluminance closed curves of each light distribution pattern are extracted, and the center of gravity of the area surrounded by each isoluminance closed curve is calculated. a calculation unit that calculates the convergence values of these center of gravity positions and outputs the convergence values as image data as the optical axis; An optical axis inspection device for a headlamp, comprising: a composite video signal generating section for outputting a composite video signal.