JPH06105210B2 - Headlight position detection method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for detecting a position of a headlight when adjusting an optical axis of a headlight of an automobile.

(Prior Art) In an automobile assembly line, adjustment is performed so that the optical axis is within a predetermined standard range after the headlight is assembled. This adjustment of the optical axis is performed so that the brightest point or bright / dark boundary line of the irradiation light of the headlight is within a predetermined standard range.

By the way, it is problematic in terms of accuracy to visually inspect the brightest point or the bright / dark boundary line of the irradiation light, and therefore, as disclosed in, for example, Japanese Patent Laid-Open No. 59-24232, it is installed in front of an automobile. A technique has been proposed that aims to improve the accuracy of the optical axis adjustment by capturing the light distribution pattern of the irradiation light projected on the screen displayed by a TV camera and processing the image. A sharp cut estimation line (bright / dark boundary line) is obtained from the position of the center of gravity of a region having a predetermined luminous intensity or higher in the pattern, and the optical axis of the headlight is adjusted so that the sharp cut estimation line is within the standard range.

When adjusting the optical axis of the headlight as described above, the left and right headlights of the automobile carried into the optical axis inspection line of the headlight are imaged by a television camera arranged in front of the automobile, and the image is taken. By subjecting the signal to image processing by the image processing device, a graphic indicating the standard of the acceptable range of the alignment pattern of the headlight of the automobile to be inspected is displayed on the screen of the monitor TV. On the other hand, the orientation pattern on the screen installed in the front of the car is imaged by another TV camera arranged above the car, and the image processing is performed on the imaged signal to obtain the brightest point of the irradiation light on the screen. The measured position of the light-dark boundary line is displayed on the screen of the monitor TV, and the measured brightest point or the light-dark boundary line is inspected on the screen of the monitor TV to see if it is outside the acceptable range. In some cases, the optical axis of the headlight is adjusted.

When inspecting and adjusting the optical axis of the headlight as described above, it is necessary to set the standard when the driver is on board, that is, when the vehicle body is sinking more than when the vehicle is empty. Since the operator other than the operator who actually performs the detection detects the position of the headlight while actually sitting in the driver's seat and sets the standard, the work efficiency of the optical axis adjustment is poor and the adjustment accuracy is also low. There was a problem.

(Object of the Invention) In view of the above-mentioned circumstances, the present invention is capable of obtaining the position data of a headlight, which is equivalent to the position data of a headlight when a passenger does not actually board a driver's seat of an automobile. The purpose is to provide a method.

(Structure of the Invention) The position detection method for a headlight according to the present invention corrects the position data by adding correction data corresponding to the amount of sinking of the vehicle body when the driver gets on the headlight position data. It is characterized by doing.

(Effect of the Invention) According to the present invention, when detecting the position of the headlight, the position data of the headlight is corrected by the correction data corresponding to the amount of sinking of the vehicle body when the driver gets on the vehicle. You can get the same headlight position data as if you were on board, without personnel on board.
The optical axis inspection and the optical axis adjustment of the headlight can be performed efficiently and highly accurately.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the overall configuration of an optical axis adjusting device to which the headlight position detecting method according to the present invention is applied. In front of the automobile 1 carried in the optical axis inspection line of the headlight, the left and right headlights 2a, Left and right screens 3a, 3b are respectively provided to which the irradiation light of 2b is irradiated. The left and right headlights of the automobile 1 are located near these screens 3a and 3b.
First television camera 4 for capturing images of 2a and 2b, respectively
a and 4b (CCD camera) are installed on the left and right. In addition, the second television cameras 5a and 5b (CCD) for capturing the light distribution pattern A of the irradiation light of the screens 3a and 3b (see FIG. 2).
Cameras) are installed on the left and right.

FIG. 2A shows a light distribution pattern of low-beam irradiation light of the headlight, which has the brightest brightest point P (center of gravity position) of the irradiation light, and the light intensity sharply increases at the boundary with the upper dark part. There is a changing light-dark boundary line L. The light-dark boundary line L is composed of a horizontal line portion a and a diagonal line portion b, and the horizontal line portion a
Relative distance D between the intersection point S of the shaded area b and the brightest point P
(XY direction component) is a constant value that does not change even if the optical axis is adjusted vertically and horizontally. Then, the acceptable range of the light-dark boundary line L is displayed as the standard light-dark line L ₀ corresponding to the position of the headlight of the automobile, and the measured or virtual light-dark boundary line L is located below the standard light-dark boundary line L _0. As described above, the optical axis is adjusted.

First TV cameras 4a, 4b and second TV camera 5
The image pickup signals obtained in a and 5b are the image processing device 6 respectively.
Entered in. Further, a signal from the operation panel 7 for operating and inputting information such as vehicle type is similarly input to the image processing device 6, and output signals from the image processing device 6 are installed near the left and right headlights 2a and 2b, respectively. Display devices 8a, 8b
Displayed on (monitor TV).

Although the specific structure of the image processing device 6 including a microcomputer is omitted, the first and second television cameras are provided.
A video signal from 4a, 4b, 5a, 5b is selectively input by an image switching device, converted into a digital signal by an A / D converter, and has a memory for storing these signals. On the other hand, arithmetic processing is performed based on the inspection program stored in the memory. A central processing unit (CPU) takes in various setting signals such as a vehicle type setting signal from an input port and outputs image information as an operation result from an output port. The controller having the video RAM which receives the signal from the output port converts the image information into a video signal and outputs the image displayed on the display devices 8a and 8b.

The first television cameras 4a, 4b illuminate the headlights 2a, 2b in the off state with light from, for example, a position below the front part of the automobile 1 to capture images of the headlights 2a, 2b, and an image is obtained from the imaging signal. The headlight shown in FIG. 3 by the processing device 6.
The upper edge 9 and the inner edge 10 that form the contours of 2a and 2b are detected, and the ground clearance WL of the headlights 2a and 2b and the left-right distance BL from the center line are obtained from this, and then a preset driver boarding A value WL ₁ is obtained by subtracting the value Δx corresponding to the amount of sinking of the vehicle body in the case of the above from the ground clearance WL of the headlights 2a and 2b. The image processing device 6 uses the WL ₁ and the BL as data representing the positions of the headlights 2a and 2b, and based on this data and the vehicle type signal (headlight specification) from the operation panel 7, the corresponding headlight is passed. The vertical and horizontal positions of the standard bright-dark boundary line L ₀ indicating the range are obtained and output to the display devices 8a and 8b to display the standard bright-dark boundary line L ₀ .

On the other hand, the second TV cameras 5a and 5b are for picking up the light distribution pattern A on the screens 3a and 3b of the left and right headlights 2a and 2b in the lighting state, and from the image pickup signal of this light distribution pattern A The brightest point P of the irradiation light by the image processing device 6
And the measured position of the light-dark boundary line L is displayed on the display devices 8a and 8b, and the intersection S between the horizontal line portion a and the diagonal line portion b of the light-dark boundary line L is obtained, and the position of the brightest point P and the position of the intersection point S are determined. Then, the relative distance D between the two is obtained and stored.

The process of obtaining the brightest point P in the image processing device 6 is performed by the following procedure. That is, the image pickup signals from the second television cameras 5a and 5b are first A / D converted, and then the image is divided into N × N (for example, 256 × 256) pixels to obtain a histogram regarding the luminance distribution of all pixels. The image is binarized by the threshold value set for this histogram, and the brightest point is obtained by calculating the barycentric position of the area of a predetermined area corresponding to the high-luminance portion of the binarized image. ing.

Further, in the process of obtaining the light-dark boundary line L, the images from the second television cameras 5a and 5b are differentiated with respect to the Y-direction axis, the horizontal line portion a of the light-dark boundary line L is obtained from this differential value, and the differential value is similarly obtained. The shaded portion b of the light / dark boundary line L is obtained from the above, and this light / dark boundary line L is displayed on the display devices 8a and 8b. Further, the intersection of the horizontal line portion a and the shaded portion b of the light-dark boundary line L is obtained, and the relative distance D (XY direction component) between this intersection S and the brightest point P is calculated and stored.

Further, when the measured light / dark boundary line L is outside the acceptable range with respect to the standard light / dark boundary line L ₀ , the image processing device 6 adjusts the optical axes of the headlights 2a, 2b to distribute the light on the screens 3a, 3b. The pattern A is moved, the brightest point P after the movement is detected by the same method as described above, the virtual bright-dark boundary line L'is obtained from the position of the brightest point P and the relative distance D, and the display device 8a,
Show on 8b. By repetition of such a procedure, the display device 8a, 8b virtual dark boundary line L 'while watching for optical axis adjustment so that the acceptance range for standard light-dark boundary line L _0.

In order to correct the displacement of the second TV cameras 5a and 5b, a reference point provided on the screens 3a and 3b is taken in, and this reference point is referred to as a position where the second TV cameras 5a and 5b take in. , Detects the positional deviation from the regular position for capturing and corrects it.

Next, the optical axis adjusting procedure in the optical axis adjusting apparatus will be described with reference to the flowcharts of FIGS. 4 to 6 together with the processing operation executed by the central processing unit (CPU) in the image processing apparatus 6. First, in step S1 of FIG. 4, the vehicle type of the automobile 1 to be carried in is input, and the automobile 1 is carried into a predetermined position of the optical axis adjustment line and stopped. Then step S2
After capturing from the first TV camera 4a, 4b to the image pickup screen of the headlight 2a, 2b, the lighting instruction of the headlight 2a, 2b is displayed in step S3, and the position of the headlight 2a, 2b is displayed in step S4. Is detected, and the standard light-dark boundary line L ₀ representing the acceptable range is calculated in step S5.

Next, in response to the lighting of the headlights 2a and 2b in step S6, the captured images of the light distribution pattern A on the screens 3a and 3b are captured from the second television cameras 5a and 5b, and the image processing of step S7 is executed. In the next step S8, adjust the optical axis,
In step S9, the comparison with the standard light-dark boundary line L ₀ calculated in step S5 is performed, and when the result is pass (OK), step S1
At 0, the screens 3a and 3b are raised to adjust the optical axes of the next headlights 2a and 2b of the automobile 1.

The details of the optical axis detection flow in step S7 are shown in FIG. 5, in which an image is captured in step S11, the image data is corrected in step S12, and a histogram is created in step S13. Next, in step S14, a threshold value is set so that the high bright area region becomes a predetermined area in this histogram, the image is binarized, and the position of the center of gravity thereof is detected to determine the brightest point P = X _p , Y. _{Find p} . If necessary, this brightest point P is displayed as "+" on the television screens of the display devices 8a and 8b, and it is determined whether or not the brightest point P is within a predetermined standard range.

Subsequently, in steps S15 to S18, the 256 sections of the image signal are differentiated in the Y direction at intervals Δx, and the differentiated value is used to calculate step S19.
Then, the horizontal line portion a of the light-dark boundary line L is obtained in the range of X _p −L ₁ <X _n , and in the next step S20, X _p −L _{2 is} calculated from the differential value.
The shaded portion b of the light-dark boundary line L is obtained within the range of> X _n , and in the next step S21, the intersections S = X _s , Y _s of the horizontal line portion a and the shaded portion b of the light-dark boundary line L are obtained. Furthermore coordinate difference between the intersection S wherein the most bright spot P in step _{S22 (X p -X s),} (Y p -Y s) from the relative distance D = d _x, calculates the d _y, and stores.

Then, the measured light / dark boundary line L is the standard light / dark boundary line.
It is determined whether or not it is located below L ₀ , and if it is out of the standard, the optical axis adjustment of the headlights 2a and 2b is disclosed. In response to the movement of the light distribution pattern A on the screens 3a and 3b due to the optical axis adjustment, the image signals are again taken in from the second television cameras 5a and 5b in step S23, and the image processing device 6 correspondingly receives the image signals. , 25, the same processing as described above is performed to detect the brightest point P after movement, and step S26
The position of the brightest point (X _p , Y _p ) after the movement by and the relative distance D =
A virtual light-dark boundary line L ′ is obtained from d _x and d _y, and step S27
Display device 8a, and displayed on 8b in, whether the 'comparison with the standard light-dark boundary line L _0, the virtual light-dark boundary line L in step S29' virtual dark boundary line L in step S28 is in the adequate range It is determined, and if the determination result in step S29 is YES, a pass display is performed in step S30. Also step S
When the determination result is NO in 29, by repeated from step S23 to step S29, the virtual dark boundary line L 'to perform optical axis adjustment so that the acceptance range for standard light-dark boundary line L _0.

Further, FIG. 6 is a flowchart showing the details of the data correction in step S12, in which the contours of the images of the headlights 2a, 2b taken from the television cameras 4a, 4b
In S31, detection is performed based on the positions of the upper edge 9 and the inner edge 10 in FIG. 3, and in the next step S32, the headlight 2 is detected.
Calculate the ground clearance WL of a and 2b and the horizontal distance BL from the center line. Next, in step S33, a value WL ₁ obtained by subtracting the sinking amount Δx of the vehicle body when a predetermined driver boarded from the ground clearance WL is obtained from WL, and in step S34 this WL ₁ and the above B
Calculate the standard based on L.

According to the present invention, by performing the above-described correction when detecting the position of the headlight, it is possible to efficiently perform the optical axis inspection and adjustment of the headlight with high accuracy without the need for a person to sit in the driver's seat of the automobile 1. .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a headlight optical axis adjusting device to which a headlight position detecting method according to the present invention is applied, and FIG. 2 shows a headlight light distribution pattern on a screen and a pass range. FIG. 3 is an explanatory diagram showing the relationship, FIG. 3 is a schematic front view of a headlight portion of an automobile, FIG. 4 is an overall flowchart of optical axis adjustment, FIG. 5 is a flowchart of image processing, and FIG. It is a flowchart of the process which corrects the data of the opened image. 1 ... Car, 2a, 2b ... Headlight, 3a, 3b ... Screen, 4a, 4b ... First TV camera, 5a, 5b ...
Second TV camera, 6 ... Image processing device, 8a, 8b ...
Display device, A ... light distribution pattern, P ... brightest point, L ...
Dark boundary line, a ...... horizontal line portion, b ...... hatched portion, S ...... intersections, L ₀ ...... standard light-dark boundary line, D ...... relative distance.

Claims (1)

[Claims] 1. A headlight position detecting method in which position data of a headlight of an automobile to be adjusted is taken in from a visual sensor and an optical axis of the headlight is adjusted based on the position data. A position detection method for a headlight, wherein the position data is corrected by adding correction data corresponding to the amount of sinking of the vehicle body when the vehicle is on board.