JP2004243895A - Automatic lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic lighting device capable of preventing a headlamp from automatically lighting when a vehicle is travelling under a bridge or passing through a shade of a building. <P>SOLUTION: The automatic lighting device monitors a forward-looking picture 5 photographed by a camera 1, and determines light or dark of the forward-looking picture 5 to turn on or off the headlamp 2 automatically. The automatic lighting device comprises luminance distribution determination means for separating the forward-looking picture 5 into two areas, a light area with high luminance and a dark area with low luminance, and automatic lighting control steps S5, S8, S9 for automatically turning on the headlamp 2, if not lighted, only when the all the luminance distribution areas judged by the luminance distribution determination means is judged as the dark area with low luminance. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of an automatic lighting device that monitors an image ahead of a vehicle captured by a camera, determines the brightness of the image ahead of the vehicle, and automatically turns on or off a headlight.
[0002]
[Prior art]
A conventional automatic lighting device adjusts the shutter speed of a CCD camera according to the amount of light according to the brightness gradation of sample image data. The shutter speed and the brightness gradation signal from the image recognition unit determine the brightness in front of the vehicle. Lighting determination means for determining and outputting a light-on or light-off signal is provided, and a headlight is automatically turned on or off by a light-on or light-off signal (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-7-318644 (page 1, FIG. 1).
[0004]
[Problems to be solved by the invention]
However, in the conventional automatic lighting device, the luminance gradation used for the lighting determination is an average value of the luminance gradation of the entire imaged region or a specific region (for example, up to 40 m ahead of the vehicle), and this value is used. Because the headlights are automatically turned on or off, for example, there is a problem that the headlights are turned on automatically when passing under a bridge or passing through the shadow of a building. is there. At this time, an oncoming vehicle or a vehicle running ahead may be mistaken for passing.
[0005]
The present invention has been made in view of the above-described problems, and is an automatic lamp that can prevent the headlight from being turned on automatically when passing under a bridge or passing through a shadow of a building. It is intended to provide a device.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention,
In an automatic lighting device that monitors a vehicle front image captured by a camera, determines the brightness of the vehicle front image, and automatically turns on or off a headlight,
Brightness distribution determining means for dividing the front image of the vehicle into two regions, a bright region of high brightness and a dark region of low brightness,
When the headlight is turned off, an automatic light control unit that automatically turns on the headlight only when it is determined that the entire region of the luminance distribution determined by the luminance distribution determination unit is a low-luminance dark region. When,
With.
[0007]
【The invention's effect】
Therefore, in the automatic lighting device of the present invention, in the automatic lighting control means, when the headlight is off, the entire area of the luminance distribution determined by the luminance distribution determining means is determined to be a low-luminance dark area. Since the headlights are automatically turned on only when they are turned off, it is possible to prevent the headlights from being turned on automatically when passing under a bridge or passing through the shadow of a building. it can.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment for realizing an automatic lighting device of the present invention will be described based on a first embodiment shown in the drawings.
[0009]
(First embodiment)
First, the configuration will be described.
FIG. 1 is a diagram showing an automatic lighting device according to a first embodiment. In FIG. 1, 1 is a camera, 2 is a headlight, 3 is a headlight mode changeover switch, and 4 is a processing device.
[0010]
The camera 1 is provided at a position above the front window, and captures an image of the front of the vehicle. This camera 1 is mainly used for a lane departure prevention device.
[0011]
When the headlamp mode is selected by the headlamp mode changeover switch 3, the headlamp 2 is turned on (turned on) / off (turned off) by an output of the processing device 4.
[0012]
The headlight mode changeover switch 3 is a means by which a driver manually switches the mode of the headlight 2. The headlight mode includes headlight ON mode / small ON mode / headlight AUTO mode / front light. There is an illumination OFF mode.
[0013]
The processing device 4 inputs a switch signal from the headlight mode changeover switch 3 to determine a switch state, and inputs image data from the camera 1 to perform image processing. Then, ON (lighting) / OFF (light-out) of the headlight 2 is controlled using these results.
[0014]
Next, the operation will be described.
[0015]
[Automatic light control processing]
FIG. 2 is a flowchart showing the flow of the automatic light control process executed by the processing device 4. Each step will be described below (automatic light control means).
[0016]
In step S1, control is started by turning on the power switch of the vehicle, and the process proceeds to step S2.
[0017]
In step S2, it is determined whether the vehicle is running based on whether the ignition switch is ON. If the ignition switch is ON, the process proceeds to step S3. If the ignition switch is OFF, the determination in step S2 is repeated.
[0018]
In step S3, when the camera 1 is off, the camera 1 is turned on, and when the camera 1 is on, the camera 1 is kept on, and the process proceeds to step S4.
[0019]
In step S4, the state of the headlight mode changeover switch 3 is determined, and if the headlight mode changeover switch 3 has selected the headlight AUTO mode, the process proceeds to step S5 and the headlight mode changeover is performed. If the switch 3 has selected a mode other than the headlight AUTO mode, the process returns to step S2.
[0020]
In step S5, it is determined whether the headlight 2 is currently ON (lit) or OFF (extinguished). If the headlight is ON, the process proceeds to step S6. If the headlight 2 is OFF, the process proceeds to step S6. Move to S8.
[0021]
In step S6, when it is determined in step S5 that the headlight 2 is turned on, it is determined whether or not the entire region of the luminance distribution determined by the luminance distribution determination unit described later is a bright region with high luminance. In the case of YES, the process proceeds to step S7, and in the case of NO, the process returns to step S5.
[0022]
In step S7, when it is determined in step S6 that the entire region of the luminance distribution is a bright region with high luminance, the headlight 2 is turned off and the process proceeds to step S2.
[0023]
In step S8, when it is determined in step S5 that the headlight 2 is turned off, it is determined whether or not the entire area of the luminance distribution determined by the luminance distribution determination unit described later is a low-luminance dark area. If the determination is YES, the process proceeds to step S9. If the determination is NO, the process returns to step S5.
[0024]
In step S9, when it is determined in step S8 that the entire area of the luminance distribution is a low-luminance dark area, the headlight 2 is turned on, and the process proceeds to step S2.
[0025]
It should be noted that the flow of proceeding from step S5 → step S8 → step S9 corresponds to the automatic light control means of claim 1, and the flow of proceeding from step S5 → step S6 → step S7 corresponds to the automatic light control means of claim 2. I do.
[0026]
[Luminance distribution determination operation]
The brightness distribution determining means divides the image in front of the vehicle captured by the camera 1 into two areas, a bright area with high brightness and a dark area with low brightness, and as shown in FIG. A plurality of brightness measurement windows 5a that are present evenly from the far side to the near side of the image 5 are defined as a brightness distribution determination area that is divided into two areas, a bright area with high brightness and a dark area with low brightness. Further, since the luminance measurement window 5a recognizes a white line indicating a lane on the vehicle front image 5 captured by the lane departure prevention camera 1, it is highly possible that a white line exists on the vehicle front image 5. A white line recognition window is used in which a plurality of white diagonal lines (C-shaped) are arranged side by side.
[0027]
For example, as shown in FIG. 3A, when a bridge crossing the road is erected in the traveling direction of the host vehicle as shown in FIG. 3A, the vehicle front image 5 captured by the camera 1 is shown in FIG. Become like Thus, when there is a bridge in the traveling direction of the host vehicle, the “bridge portion” and the “shadow portion of the bridge” which are part of the vehicle front image 5 are darkened.
[0028]
When this is monitored by the luminance measurement window 5a (= white line recognition window), the luminance measurement window 5a including the “bridge portion” and the “shadow portion of the bridge” (the window surrounded by the solid line in FIG. 3B) ) Is determined to be a dark area whose luminance is lower than the threshold value, and the luminance measurement window 5a (a window surrounded by a dotted line in FIG. 3B) not including the “bridge portion” and the “shadow portion of the bridge” is not included. ) Is determined to be a bright region whose luminance is higher than the threshold value.
[0029]
In addition, even when the own vehicle passes through the shadow of the building, the “shadow portion of the building”, which is a part of the image 5 in front of the vehicle, becomes dark and, like the case where there is a bridge in the traveling direction of the own vehicle, It is determined that the brightness of some of the brightness measurement windows 5a among the plurality of brightness measurement windows 5a is a dark area lower than the threshold.
[0030]
[Automatic light control action]
The automatic light control operation when the driver switches the headlight mode changeover switch 3 to the headlight AUTO mode and travels in the daytime will be described.
[0031]
First, when the headlight 2 is turned off and passes under a bridge or passes through a shadow of a building, in the flowchart of FIG. 2, step S1 → step S2 → step S3 → step S4 → step S5 → step S8. In step S8, since it is determined that the brightness of some of the brightness measurement windows 5a is a dark area lower than the threshold (mixing of light and dark in FIG. 4B), the operation of returning from step S8 to step S5 is repeated. Thus, the extinguishing state of the headlight 2 is maintained as it is.
[0032]
When it is determined that the own vehicle enters a tunnel or the like and the brightness of all the brightness measurement windows 5a is a dark area lower than the threshold (dark in all windows in FIG. 4C), the process proceeds from step S8 to step S9. Then, the headlight 2 in the unlit state is turned on.
[0033]
Further, during the passage through the tunnel, in the flowchart of FIG. 2, the process proceeds to step S2 → step S3 → step S4 → step S5 → step S6. For this reason, the operation of returning from step S6 to step S5 is repeated, and the lighting state of the headlight 2 is maintained as it is.
[0034]
When it is determined that the vehicle has exited the tunnel and that the brightness of all the brightness measurement windows 5a is a bright area higher than the threshold (bright in all windows in FIG. 4A), the process proceeds from step S6 to step S6. Proceeding to S7, the headlight 2 in the lighting state is turned off.
[0035]
Next, effects will be described.
In the automatic lighting device according to the first embodiment, the following effects can be obtained.
[0036]
(1) In an automatic lighting device that monitors a vehicle front image 5 captured by the camera 1 and determines the brightness of the vehicle front image 5 to automatically turn on or off the headlights 2, the vehicle front image 5 A luminance distribution determining unit that divides the region into two regions, a bright region with high luminance and a dark region with low luminance; and when the headlight 2 is off, the entire region of the luminance distribution determined by the luminance distribution determining unit has low luminance. And automatic lighting control steps S5, S8 and S9 for automatically turning on the headlight 2 only when it is determined that the area is a dark area. The headlight 2 can be prevented from being automatically turned on when passing through the vehicle. As a result, an oncoming vehicle or a vehicle running ahead of the host vehicle does not need to be misunderstood or anxious that the vehicle is passing. Furthermore, when compared with an automatic lighting device using a light receiving sensor, a light receiving sensor is not required, and the number of components can be reduced.
[0037]
(2) The automatic lamp control steps S5, S6, and S7 are performed when the headlight 2 is turned on and the entire region of the luminance distribution determined by the luminance distribution determination unit is determined to be a high-luminance bright region. Only the headlamp 2 is automatically turned off, so that the headlamp 2 can be kept lit until it completely passes through a dark place such as a tunnel.
[0038]
(3) The luminance distribution determination means divides a plurality of luminance measurement windows 5a which are present evenly from the far side to the near side of the image 5 in front of the vehicle into two regions, a bright region having a high luminance and a dark region having a low luminance. Since the distribution determination area is used, if there is an area determined to be bright far from the small area determined to be dark in the plurality of luminance measurement windows 5a, the vehicle passes under a bridge or a shadow of a building after a predetermined time. Thus, it is possible to reliably prevent the headlight 2 from being automatically turned on when passing under a bridge or a shadow of a building.
[0039]
(4) Since the luminance measurement window 5a of the luminance distribution determination means recognizes a white line indicating a lane on the vehicle front image 5 captured by the camera 1, there is a high possibility that a white line exists on the vehicle front image 5. Since the white line recognition window is set in a plural number on each of two vertical and diagonal lines, the white line recognition window used in the lane departure prevention device and the automatic driving control device etc. is used as it is, and the automatic lighting device can be manufactured at low cost. It can be used as a plurality of brightness measurement windows 5a that exist evenly from the far side to the near side of the vehicle front image 5.
[0040]
As described above, the automatic lighting device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and the invention according to each claim of the claims is described. Changes and additions of the design are permitted as long as the gist of the above is not deviated.
[0041]
For example, in the first embodiment, an example is described in which a white line recognition window used in a lane departure prevention device or the like is used as a luminance measurement window of a luminance distribution determination unit. However, a luminance different from the white line recognition window is used as an automatic lighting device. A measurement window may be set.
[Brief description of the drawings]
FIG. 1 is an overall system diagram showing an automatic lighting device according to a first embodiment.
FIG. 2 is a flowchart illustrating a flow of an automatic lighting control process executed by the processing device of the automatic lighting device according to the first embodiment.
FIG. 3 is a plan view of the vehicle equipped with the automatic lighting device of the first embodiment when passing under a bridge, and shows a front image of the vehicle in which a luminance measurement window is determined.
FIG. 4 is a view showing an image in front of the vehicle when the automatic lighting device of the first embodiment is mounted, when the image is determined to be bright in all windows; It is a figure which shows an image, and a figure which shows the vehicle front image when it is determined that all windows are dark.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Camera 2 Headlight 3 Headlight mode switch 4 Processing device 5 Image 5a in front of vehicle Brightness measurement window

Claims (4)

In an automatic lighting device that monitors a vehicle front image captured by a camera, determines the brightness of the vehicle front image, and automatically turns on or off a headlight,
Brightness distribution determining means for dividing the front image of the vehicle into two regions, a bright region of high brightness and a dark region of low brightness,
When the headlight is turned off, an automatic light control unit that automatically turns on the headlight only when it is determined that the entire region of the luminance distribution determined by the luminance distribution determination unit is a low-luminance dark region. When,
An automatic lighting device comprising: The automatic lighting device according to claim 1,
When the headlight is on, the automatic light control means automatically turns on the headlight only when it is determined that the entire area of the luminance distribution determined by the luminance distribution determination means is a bright area with high luminance. An automatic lighting device characterized in that the light is turned off. In the automatic lighting device according to claim 1 or 2,
The brightness distribution determination means includes a brightness distribution determination area that divides a plurality of brightness measurement windows that exist evenly from the far side to the near side of the image ahead of the vehicle into two areas, a bright area having a high brightness and a dark area having a low brightness. Automatic lighting device characterized by performing. The automatic lighting device according to claim 3,
The luminance measurement window of the luminance distribution determining means is provided on two vertical and diagonal lines that are likely to have a white line on the vehicle front image in order to recognize a white line indicating a lane on the vehicle front image captured by the camera. An automatic lighting device, wherein a plurality of white line recognition windows are set and arranged.

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