JPH11235949A - Light distribution control device for automotive headlights - Google Patents

Abstract

(57) [Problem] To provide a light distribution control device for a headlight for an automobile so as to efficiently illuminate a traveling lane in consideration of illuminance from a peripheral light source other than a headlight such as a street light. SOLUTION: A target luminance distribution calculating means 5C calculates a target luminance distribution of a traveling road ahead of a host vehicle illuminated by a headlight 9 and an actual luminance distribution detecting means 3A detects an actual luminance distribution of the traveling road. Then, the target luminance distribution calculated by the target luminance distribution calculating means 5C by the optical axis angle target value calculating means 5 and the actual luminance distribution detected by the actual luminance distribution detecting means 3A are compared, and the actual luminance distribution is determined based on the comparison result. The target value of the optical axis angle that makes the luminance distribution close to the target luminance distribution is calculated. The control means 7 adjusts the optical axis angle of the headlight 9 via the optical axis actuator 8 to be equal to the optical axis angle target value calculated by the optical axis angle target value calculating means 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling light distribution by controlling an optical axis angle of a headlight for an automobile, and particularly to changing an optical axis of the headlight by paying attention to a luminance distribution on a traveling road. And a light distribution control device for an automobile headlight.

[0002]

2. Description of the Related Art Generally, a headlight for an automobile is configured to be capable of switching between a high beam and a low beam. By switching between the high beam and the low beam, a driver can select an optical axis angle of the headlight according to road conditions. It has become. However, this switching of the high beam / low beam only switches the optical axis angle in the vertical direction, and does not change the optical axis angle in the horizontal direction.
The optical axis of the headlight is always fixed in the vehicle center line direction. For this reason, when the vehicle's center line deviates from the direction of the road ahead of the vehicle, such as a curved road, it is not possible to effectively illuminate the road surface ahead of the vehicle where the vehicle is going to travel. Also, the vertical optical axis angle can be adjusted only in two stages of high beam / low beam, and a finer adjustment of the optical axis angle is desired depending on the situation. On the other hand, the finer the adjustment of the optical axis angle becomes, the more troublesome the manual operation becomes and the more difficult it is to effectively use it.

In order to respond to such demands and problems, various proposals have been made on light distribution control of headlights for automobiles. In particular, as a technique for performing lateral light distribution control, Japanese Patent Application Laid-Open No. 6-206491 discloses a technique for controlling a lateral optical axis angle of a headlight corresponding to a curve. In this technique, a rotational angular velocity and a vehicle speed at the time of turning of a vehicle are detected by using an angular velocity sensor and a vehicle speed sensor, and a lateral optical axis of a headlight is calculated in accordance with a curve radius calculated based on the detected values. It changes the angle.

The technique disclosed in Japanese Patent Application Laid-Open No. 7-232589 similarly controls the lateral optical axis angle of a headlight corresponding to a curve. In this technique, an acceleration sensor is used. The vehicle acceleration and the vehicle speed are detected by using the vehicle speed sensor and the vehicle speed sensor, and the optical axis angle in the horizontal direction is changed in accordance with a curve radius calculated based on the detected values.

As a device for controlling light distribution in the vertical direction, there is an apparatus disclosed in Japanese Patent Laid-Open No. 1-278848. In this device, the vertical angle of the optical axis is controlled according to the distance to the preceding vehicle.

[0006]

By the way, in general, the traveling lane is illuminated not only by the light from the headlamp of the own vehicle, but also by the light from the headlamp of another vehicle, the light from a street lamp, or the like. Occasionally, the traveling lane may be brightly illuminated by light other than the headlamps of the own vehicle. If the driving lane already has sufficient illuminance, illuminating it further with the headlamp of the host vehicle is inefficient.

In such a case, instead of further illuminating a place having a sufficient illuminance, if a place having a relatively low illuminance can be illuminated, a wide area can be efficiently and uniformly illuminated. The driver can ensure good visibility. Therefore, it is conceivable to control the optical axis angle of the headlight so that the traveling lane can be efficiently emitted in consideration of the illuminance from a peripheral light source such as a street light.

Japanese Patent Application Laid-Open No. 4-66343 discloses a technique for controlling the light distribution of headlights in accordance with the illuminance distribution in the traveling lane ahead of the vehicle. However, this technique attempts to change the light distribution of the headlights of the own vehicle in order to prevent the evaporation of a forward obstacle due to irradiation from an oncoming vehicle, and is not a solution to the above problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has been made in consideration of the illuminance from a peripheral light source other than a headlight such as a street light, and is capable of efficiently illuminating a traveling lane. It is an object of the present invention to provide a light distribution control device.

[0010]

Therefore, in the light distribution control device for a headlight for an automobile according to the present invention, a target luminance distribution is calculated by a target luminance distribution calculating means on a traveling path in front of the vehicle to be irradiated by the headlight. At the same time, the actual luminance distribution of the traveling road is detected by the actual luminance distribution detecting means. Then, the target luminance distribution calculated by the target luminance distribution calculating means by the optical axis angle target value calculating means is compared with the actual luminance distribution detected by the actual luminance distribution detecting means, and the actual luminance distribution is calculated based on the comparison result. Is calculated so as to approach the target luminance distribution. The controller adjusts the optical axis angle of the headlight via the optical axis actuator so as to be equal to the optical axis angle target value calculated by the optical axis angle target value calculator.

Thus, it is possible to efficiently illuminate the traveling lane in consideration of the illuminance from a light source other than a headlight such as a street light.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a first embodiment of the present invention; FIG.
1 shows a light distribution control device for a headlight for an automobile as an embodiment. As shown in FIG. 1, the light distribution control device includes a camera 2 as an imaging unit that captures an image of a road state ahead of the vehicle in order to recognize a position of the own vehicle with respect to a traveling lane (traveling lane). Information processing means 3 for appropriately processing the image information from the vehicle and recognizing the left and right white line positions on the front road, and calculating the road curvature ρ of the driving lane of the vehicle from the white line position image information by the image information processing means 3 It has a road curvature calculating means 4A. The road curvature calculating means 4A is provided as a functional element in the traveling lane estimating means 4 for estimating the relative position of the traveling lane (traveling lane) with respect to the own vehicle.

In addition, the light distribution control device may calculate the road curvature based on the lateral acceleration G and the vehicle speed V of the vehicle, in addition to the road curvature calculation unit 4A that calculates based on the white line position image information. A substitute road curvature calculating means 25 for calculating a road curvature (estimated road curvature ρ ') is provided.
To recognize the relative position of the preceding vehicle with respect to the own vehicle,
A radar (preceding vehicle detecting means) 26 as detecting means for detecting the presence of a preceding vehicle ahead of the own vehicle, and the relative position of the preceding vehicle with respect to the own vehicle by processing radar information from the radar 26 as appropriate, that is, the own vehicle and a preceding vehicle position calculating means 27 for calculating the deflection angle theta _F of the preceding vehicle with respect to the distance L _F and the vehicle center line between the preceding vehicle and.

Further, the present light distribution control device determines a vertical optical axis angle target value θ ₁ based on the calculated road curvature ρ or the estimated road curvature ρ ′ and the position information of the preceding vehicle with respect to the own vehicle.
And an optical axis angle target value calculating means 5 for calculating a lateral optical axis angle target value θ ₂ , an optical axis actuator 8 for moving the optical axis of the headlight 9, and an optical axis angle of the headlight 9. A control means (controller) 7 for controlling the optical axis actuator 8 so as to be equal to the optical axis angle target values θ ₁ and θ ₂ calculated by the value calculation means 5 is provided.

In order to feed back the illuminance information of the traveling lane by the peripheral light source such as a street light, the illuminance of the actual traveling lane is used for calculating the optical axis angle target values θ ₁ and θ _{2 in} the optical axis angle target value calculating means 5. That is, it includes an actual luminance distribution detecting means 3A for detecting the luminance distribution, a target luminance distribution calculating means 5C for calculating the luminance distribution of the traveling lane by the headlight 9, and a comparison processing means 29 for comparing these luminance distributions. I have.
The actual luminance distribution detecting means 3A is a functional element of the image information processing means 3, and the target luminance distribution calculating means 5C is a functional element of the optical axis angle target value calculating means 5.

Incidentally, image information processing means 3, traveling lane estimating means 4, substitute road curvature calculating means 25, preceding vehicle position calculating means 27, target luminance distribution calculating means 28, comparison processing means 29, optical axis angle target value calculating means 5, the controller 7 is C
It is configured as an electronic control unit including a PU, an input / output interface, a ROM, a RAM, and the like. First, the calculation of the road curvature ρ of the traveling lane will be described.

In the image information processing means 3, first, as shown in FIG. 2, an original image 3A from the camera 2 is taken in, a road white line is extracted from the original image 3A, and an image of the extracted road white line is converted into a vertical image. The image is converted into a two-dimensional image 3B as viewed from above. Here, recognition of the white lines 12L and 12R will be described with reference to FIG. Here, the recognition of the white line 12L as the roadside line at the left end of the traveling lane will be described. However, the same applies to the case where the white line 12R at the right end of the traveling lane is used as a reference. I will call it.

As shown in FIG. 3 (a), the image information recognizing means 3 fetches black and white image information in a range in front of the vehicle on a flat ground by a camera 2 provided in the vehicle, and reads the image information in a vertical direction on a screen. Are partially omitted. Then, a plurality of horizontal lines 11 at equal intervals on this screen
Set. The capture of the black-and-white image information is updated every minute control cycle. As shown in FIG. 3B, on each horizontal line 11, the left and right positions of the white line position on the previous screen are required. Range [here, left and right 5
0 pixel (dot)] to the white line search area (processing target area)
Set as 10. For the first screen, the white line position on the straight road is used as the previous screen data.

Then, as shown in FIG. 3C, the brightness of each horizontal line is differentiated in the horizontal direction from the left. Reference numeral 14 in the figure is a guardrail. By the way, a normal road surface has low luminance and a small change in luminance. On the contrary,
Since the brightness of the white line 12 is much higher than that of the normal road surface, when the brightness of the road is differentiated in this way, the luminance change is positive at the boundary point from the normal road surface to the white line 12, and the white line 12 changes to the normal road surface. Differential data is obtained such that the luminance change becomes negative at the boundary point of. An example of such differential data is shown in FIG.

The peaks of the differential values appear in the order of plus and minus from the left with respect to the data of each horizontal line 11, and the interval between the respective peaks is the white line 12.
Is extracted as a candidate for a white line, and a combination that falls within a reasonable degree (interval between a positive peak and a negative peak is within 30 dots, for example) is extracted.
As shown in FIG. 3E, the midpoint M is set to the white line candidate point 15.
Save as

Then, among these white line candidate points 15,
Only the point closest to the screen center is left as the final candidate point.
This is because, for example, when the vehicle is traveling on the left side, the search area 10
The right side of the road is a road surface where the normal luminance change is small, and the white line candidate point 15 closest to the normal road surface can be determined as the white line 12. Therefore, even when there is an object (for example, the guardrail 14) that causes noise on the left side of the white line 12, the white line 12 can be reliably recognized from the image information captured by the camera 2.

Finally, as shown in FIG. 3F, the vertical continuity of the white line candidate points 15 in each horizontal line data is sequentially verified from the bottom of the screen. First, the inclination between the upper and lower ends of the white line 12 on the previous screen is calculated in advance.
Then, assuming that the lowest point 15A is the white line 12, it is verified whether or not the candidate point 15B on the horizontal line 11 which is only one line above is within the range of ± 50 dots of the inclination of the previous white line 12 (within the error range). .

If the candidate point 15B falls within this range, it is regarded as a white line. If not, the candidate point 15B is rejected, and the coordinates interpolated from the above-mentioned inclination are regarded as the white line position. By performing the same operation for each horizontal line for this detection, a continuous white line 12 can be recognized. Such white line recognition work is continuously performed at a required cycle, and the recognition of the white line 12 is updated each time.

The white line 12 as the roadside line at the right end of the traveling lane
The recognition of R is performed in the same manner. By the way, even when the candidate point 15 which does not fall within the error range exists as described above, the white line 12 can be recognized by performing the interpolation calculation from the inclination between the upper and lower ends of the white line 12 in the previous screen. However, if many of the candidate points 15 on the screen are rejected because they do not fall within the error range, it cannot be said that the white line on the road surface can be recognized effectively. Can not expect precise control. Therefore, in the image information processing means 3, the candidate points 15
Is rejected, the recognition loss signal is output to the optical axis angle target value calculation means 5 assuming that the white line recognition is malfunctioning. However, if either one of the left and right white lines 12L and 12R is effectively recognized, control can be performed based on the effectively recognized white line 12, and no recognition lost signal is output.

The image information processing means 3 recognizes a road white line ahead of the vehicle, and, based on the black-and-white image information of the front of the vehicle captured by the camera 2, outputs a luminance distribution in a predetermined range on the road ahead of the vehicle. Is to be detected. This luminance distribution is detected by the actual luminance distribution detecting means 3A, which is a functional element of the image information processing means 3, and the detected luminance distribution is a two-dimensional plane map, that is,
A luminance map (hereinafter, referred to as an actual luminance distribution map) for each pixel arranged vertically and horizontally in an image captured by the camera 2 is obtained. The actual brightness distribution detecting means 3A inputs the created real brightness distribution map to a comparison processing means 29 described later.

In the traveling lane estimating means 4, the white lines 12R, 1R on the original image 3A recognized in each recognition cycle
Converts 2L in plan view image 3B, on the basis of the road centerline LC _R which may be estimated from the travel lane left to the road central line LC _L which can be estimated from the white line 12L traveling lane right edge of the white line 12R, the center line of the road The LC is estimated. Then, based on the road center line LC, the road curvature calculating means 4A calculates the road curvature ρ of the traveling lane ahead of the vehicle.

As shown in FIG. 4A, the road curvature calculating means 4A includes a plurality of matching circular arc patterns 3 having different curvatures.
0 are stored, and these matching arc patterns 30 are stored.
Is superimposed on the road center line LC on the planar view image 3B to check whether or not they match. As a matching method, for example, an arc pattern having a curvature of 0 (that is, a straight line)
, And sequentially superimpose on the road center line LC on the planar view image 3B. Then, for example, as shown in FIG.
Using the least squares method, the distance (the number of dots between two points) between the matching arc pattern 30 on the horizontal line 11 and the road center line LC on the horizontal line 11 is sequentially squared from the bottom of the screen and integrated. Is compared to the integrated value in the matching circular arc pattern 30 that was previously compared.

At this time, the current matching arc pattern 30
If the integrated value is smaller, the collation with the next collation arc pattern 30 is performed again. On the other hand, if the integrated value in the current matching arc pattern 30 is larger, the previous matching arc pattern 30 is regarded as an arc pattern that matches the road center line LC, and the curvature of this arc pattern is defined as the road curvature ρ. It is supposed to.

The lateral displacement amount calculating means 4B and the yaw angle calculating means 4
In C, the image information of the road center line LC and the road center line L
The lateral shift amount ΔY and the yaw angle β are calculated based on the position information of the own vehicle with respect to C, respectively. That is, as shown in FIG. 5, the lateral displacement amount calculating means 4B calculates the lateral distance (road width) between the first detection point (LC1), which is a point on the road center line LC closest to the vehicle 1, and the vehicle center line. The direction, that is, the distance in the lateral direction of the camera image) is calculated as the lateral deviation amount ΔY, and the yaw angle calculating unit 4C makes a tangent to the road center line LC at the first detection point (LC1) and the vehicle center line. The angle is calculated as the yaw angle β.

On the other hand, the substitute road curvature calculating means 25 calculates the estimated road curvature ρ 'as follows. That is, assuming that the lateral acceleration based on the centrifugal force acting on the vehicle is G, and the magnitude of the speed of the vehicle at that time is V, the estimated road curvature ρ ′ of the currently running road portion is calculated by the following equation. You.

Ρ ′ = G / V ² (1) Therefore, the substitute road curvature calculating means 25 calculates the lateral acceleration G by using the lateral acceleration sensor (lateral acceleration detecting means) 21. The vehicle speed (traveling speed detecting means) 20 detects the vehicle speed (traveling speed) V, and the estimated road curvature ρ 'is calculated from the equation (1) based on these detected values. I have.

Next, the calculation of the preceding vehicle position by the preceding vehicle position calculating means 27 will be described. The preceding vehicle position calculating means 27 detects the preceding vehicle position ahead of the own vehicle based on the information detected by the radar 26. It has become. A plurality of radars 26 are provided on the front of the vehicle with their directions slightly shifted left and right little by little. Energy (for example, laser, microwave, ultrasonic wave, etc.) having higher directivity than each radar 26 is directed toward the front of the vehicle. Transmission and reception are always performed at a predetermined cycle. Preceding vehicle position calculating means 27, as well as measure the distance L _F between the own vehicle and the preceding vehicle based on the time from transmission of the energy in the radar 26 to the reception of reflected energy from the preceding vehicle,
The deflection angle θ _F of the preceding vehicle with respect to the center line of the host vehicle is measured based on the direction of the radar 26 that has received the reflected energy.

The optical axis angle target value calculating means 5 first calculates the road curvature ρ or estimated road curvature ρ 'of the traveling lane calculated as described above, the distance L _{F of the} preceding vehicle, and the declination θ _F. Vertical optical axis angle target value θ ₁ , horizontal optical axis angle target value θ
Calculate ₂ . That is, the optical axis angle target value calculating means 5 is configured as shown in FIG.
As shown in (a) to (c), the map has a polar coordinate system represented by a distance L from the host vehicle (origin) and a declination θ with respect to the host vehicle center line (vertical axis). The optical axis angle target values θ ₁ and θ ₂ are set based on this map. That is, when an arbitrary point is taken on this map, the deviation angle θ of that point with respect to the vertical axis becomes the horizontal optical axis angle target value θ ₂
Next, The distance L between the point and the origin becomes the irradiation distance L _H of the headlight 9. Since the irradiation distance L _H is determined by the height above the ground of the headlight 9 and the optical axis angle θ _{1 in the} vertical direction, the target optical axis angles θ ₁ and θ ₂ are set by setting the irradiation target point on this map. I can do it. For example, the change taking the irradiation target point along a concentric circular arc shown in FIG. 6 (a) ~ (c) , in the longitudinal direction of the transverse direction while an optical axis angle theta ₁ is a constant optical axis angle target value theta ₂ Can be done.

Note that θ in FIGS. 6A to 6C_L,
θ_RIs the horizontal optical axis angle target value θ in the horizontal direction._Twoof
Limit angle, arc L_max, L_minIs the irradiation distance
Release L _HAre the longest distance and the shortest distance. Accordingly
And the optical axis angle target value θ₁, Θ_TwoAre these limit angles θ_L,
θ_R, Arc L_max, L_minWithin the sector enclosed by
The range corresponds to the range where the headlight 9 can be irradiated.
Function range S). The longest
Irradiation distance L_maxMay be fixed at all times, and the vehicle speed V
It may be changed accordingly.

In the optical axis angle target value calculating means 5, FIG.
As shown in (c), according to the information of the road curvature ρ of the road center line LC input from the road curvature calculation means 4A, the map is extended from the own vehicle position on the map (here, the yaw of the own vehicle). (It is assumed that the angle and the lateral shift amount are 0, and the origin is tangent to the vertical axis at the origin.) An arc of curvature ρ is drawn, and the distance L _{F of the} preceding vehicle input from the preceding vehicle position calculating means 27 and the argument θ _If there is a preceding vehicle based on the information of _F , its position is plotted on a map. This preceding vehicle position, as shown in FIG. 6 (b), (c) , take the L _F, C _F point corresponding to theta _F on the map, the point C _F
The predetermined range A _F around, for example, glare range A _F diameter d _F centered on point C _F the preceding vehicle is adapted to set as a range to be generated.

First, the optical axis angle target value calculating means 5 is configured as shown in FIG.
(A), the intersection at the control point to the road center line LC and the arc L _min (irradiation target point of the headlight) takes the candidate point P ₁ of P, between the origin 0 to the candidate point P ₁ It is verified whether the glare occurrence range _AF exists. If not interfere with the glare source range A _F in the candidate point P _1, the following is an arc L slightly larger arc than _min and the road center line L
The intersection of the C as a candidate point P _2, is adapted to verify the interference of the glare source range A _F in the candidate point P _2. Then, interference with the glare occurrence range _AF is verified along the road center line LC in this way, and verification is performed up to the intersection P _max between the road center line LC and the arc L _max .

[0037] Thus it was verified from the intersection of the center line of the road LC and the arc L _min to the intersection P _max of the road center line LC and the arc L _{ma x} no interference with the glare source range A _F, the road center line LC and an intersection point P _max of the arc L _max is determined as the control point P, the optical axis angle target value theta ₁ corresponding to the control point P, is adapted to set the theta _2. In such a case, for example, when there is no preceding vehicle, even if there is a preceding vehicle, the vehicle is traveling ahead of the irradiation range S, or traveling in a traveling lane outside the traveling lane of the own vehicle. If you do.

On the other hand, as shown in FIGS. 6B and 6C,
From the intersection of the road center line LC and the arc L _min , the road center line L
The candidate point P _k is moved along C, and the glare occurrence range A _F
Interference when began to verify and, when taking a candidate point P _n to an intersection between a certain arc L _n and the road center line LC, at the candidate point P _n, from the origin 0 to the candidate point P _n If there is a glare source range a _F and interferes portion therebetween, the intersection P _n-1 of the previous arc L _n-1 and the road center line LC of the arc L _n and the control point P, the control The optical axis angle target values θ ₁ and θ ₂ are set corresponding to the point P. Such a case includes, for example, a case where a preceding vehicle exists in front of the traveling lane of the own vehicle (FIG. 6B) and a case where the vehicle is traveling in a traveling lane inside the traveling lane of the own vehicle [FIG. 6
(C)].

In FIG. 6A, when the road curvature ρ is large and the candidate point _Pk is moved along the road center line LC, when the left and right limit angles θ _L and θ _R are reached. Is set as a control point P, and the optical axis angle target values θ ₁ and θ ₂ are set corresponding to the control point P. That is, the optical axis angle target value theta ₂ in the lateral direction in this case is a limit angle theta _L or theta _R.

The target values of the optical axis angles θ ₁ and θ ₂ are set in this way. In actual running, the vehicle is not necessarily running on the road center line LC. As shown in FIG. 5, the vehicle is laterally offset from the road center line LC, or is running with an inclination with respect to the road center line LC. Therefore, the optical axis angle target value calculating means 5 corrects the optical axis angle target values θ ₁ and θ ₂ calculated as described above, in particular, the lateral optical axis angle target value θ ₂ with respect to the lane position. Means 5B
The correction is made by the following.

The lane position corresponding correction means 5B includes a vehicle lateral displacement amount ΔY calculated by the lateral displacement amount calculating means 4B and a yaw angle β formed by the vehicle with respect to the road center line LC calculated by the yaw angle calculating means 4C. Based on the horizontal optical axis angle target value θ
₂ is determined. That is, the correction angle dθ is represented by the following equation. dθ = β-ΔY / L ············· (2) vs. lane position-dependent correction means 5B is by dividing the correction angle d [theta] from the horizontal direction optical axis angle target value theta ₂ As a result, a correction according to the lateral displacement and inclination of the vehicle with respect to the road center line LC is performed.

Thus, the lane position correspondence correcting means 5B
The optical axis angle target value θ ₂ is appropriately corrected by the above, and the vertical optical axis angle target value θ ₁ , for accurately irradiating the center of the traveling road,
Lateral optical axis angle target value theta ₂ is adapted to be set. The optical axis angle target value calculating means 5 further corrects the set optical axis angle target values θ ₁ and θ ₂ according to the illuminance of the surrounding environment.

That is, the optical axis angle target value calculating means 5 is provided with
Optical axis angle target value θ according to illuminance of environment ₁, Θ_TwoCorrect
Distribution correction means 5D for the
I have. The brightness distribution correspondence correction means 5D calculates the optical axis angle target value.
Optical axis angle target value θ set by calculation means 5₁, Θ_TwoBy f
Brightness distribution that could be obtained only by light irradiation
And the actual luminance distribution detected by the camera 2 (the actual luminance distribution
Cloth) to understand the lighting conditions other than the headlight 9
Optical axis angle so that the driving lane can be illuminated more efficiently.
Standard value θ₁, Θ_TwoAnd the comparison processing means 2
The correction amount is determined based on the information from step 9.
You.

Here, the optical axis angle target value θ according to the luminance distribution
_A description will be given of a series of processings for correcting ₁ and θ _{2. In} the present light distribution control device, the actual luminance distribution map obtained by the above-described actual luminance distribution detecting means 3A and the optical axis angle target value calculating means 5 are set. The comparison processing means 29 compares the brightness distribution map which would be obtained only by the light irradiation of the headlights with the optical axis angle target values θ ₁ and θ ₂ , and based on the result, the brightness distribution correspondence correction means 5 D The shaft angle target values θ ₁ and θ ₂ are corrected.

More specifically, a target luminance distribution calculating means 5C, which is a functional element of the optical axis angle target value calculating means 5, is provided. A target brightness distribution map is created based on the optical axis angle target values θ ₁ and θ ₂ calculated by the means 5. That is, if the optical axis angle target values θ ₁ and θ ₂ are given, the center position (luminance center) C _a of the optical axis in the visual field range ahead of the host vehicle can be known, and the light amount distribution from the headlight 9 is the optical axis Since the luminance distribution is known according to the angle, the luminance distribution on the traveling lane due to the irradiation of the headlight 9 can be estimated from these values.
C is the light amount of the headlight 9 and the optical axis angle target values θ ₁ and θ ₂
And a target luminance distribution is calculated based on the target luminance distribution map, and a two-dimensional plane map (hereinafter, referred to as a target luminance distribution map) similar to the actual luminance distribution map created by the actual luminance distribution detecting means 3A is created. Note that the target luminance distribution map and the actual luminance distribution map respectively show the target luminance distribution and the actual luminance distribution in the same range within the visual field range in front of the host vehicle.

The comparison processing means 29, as shown in FIG.
Target brightness distribution map M _a and the actual luminance distribution detecting means 3A is adapted to compare the process and the actual luminance distribution map M _b created the target luminance distribution calculating section 5C has created. This processing will be described in detail. The comparison processing means 29 includes a function (a correction luminance distribution map generation unit) 29A for generating a correction luminance distribution map _Mf for correcting the optical axis angle target value, and a correction luminance distribution map _Mf. distribution function of calculating a correction amount of the optical axis angle target value based on the map M _F (correction amount calculation unit) equipped with a and 29B, each of these functions 29A, the luminance of the optical axis angle target value calculating means 5 through 29B Correction amount information to be fed back to the distribution correspondence correction means 5C is calculated.

First, a correction luminance distribution map creating section 29A
In calculates the brightness difference on the corresponding pixels of the headlight corresponding luminance distribution map M _e created in the control period of the actual luminance distribution map M _b before, the calculated luminance difference as the luminance of the pixel A correction luminance distribution map _Mf is created. That is, here, the illuminance deviation caused by peripheral light sources other than the headlights 9 such as street lights is removed by removing the illuminance of the target to be illuminated through the headlights 9 from the illuminance actually illuminating the traveling lane. Is calculated.

On the other hand, in the correction amount calculation section 29B, the luminance center C _{f of} the correction luminance distribution map _Mf created by the correction luminance distribution map creation section 29A, that is, each pixel on the map is weighted by luminance. Calculate the center of gravity of the map in the case,
Moreover, the sum of the luminance of the correction luminance distribution map M _f sigma _f,
That is, the sum of the luminance on all the pixels on the correction luminance distribution map _Mf is calculated.

Further, the target luminance distribution calculating means 5
It calculates a luminance center C _a of the target brightness distribution map M _a input from C, going from the brightness center C _f of the correction luminance distribution in the luminance center C _a target brightness distribution vector C _f C _a (d
x, dy). Note that dx,
dy is the difference in the number of pixels between the luminance centers C _a and C _{f in} the X direction (traveling road width direction) and the Y direction (traveling road traveling direction). Here, the lower left end of the luminance distribution map is represented by the XY coordinate system. It is the origin.

The comparison processing means 29 outputs the correction luminance distribution map M _f calculated by the correction amount calculating section 29B.
Brightness and total sigma _f of, going from the brightness center C _f of the correction luminance distribution in the luminance center C _a target brightness distribution vector C _f C
_a (dx, dy) is input to the luminance distribution correspondence correction means 5D. That is, the comparison processing means 2
9 to the luminance distribution correspondence correction means 5D includes the total sum Σ _f of the luminance of the correction luminance distribution map _Mf based on the difference between the actual luminance distribution and the luminance distribution by the headlight 9 in the previous control cycle. luminance center C from the luminance center C _f of the correction luminance distribution map M _f target brightness distribution map M _a
vector towards _{a C f C a (dx,} dy) is, luminance distribution corresponding correction means 5A the total luminance sigma _f, the vector _{C f C a (dx, dy} ) optical axis angle target value theta ₁ based on,
The correction of θ ₂ is performed.

In the correction of the optical axis angle target values θ ₁ and θ ₂ , the brightness distribution correspondence correction means 5 D ′ firstly outputs the vector C _f C _a (dx, d) input from the comparison processing means 29.
so that the optical axis of the headlight is corrected in the direction of y)
Optical axis angle target value θ _1, θ ₂ of the compensation amount d [theta] _1, is adapted to set a d [theta] _2. Further, the correction amounts dθ ₁ and dθ ₂ become larger as the sum Σ _f of the luminances of the correction luminance distribution increases.
, That is, as the illuminance of the external light source is higher, the correction amounts dθ ₁ and dθ ₂ are set to be larger.

That is, the vertical optical axis angle target value θ₁Correction
Quantity dθ₁, Transverse optical axis angle target value θ _TwoCorrection amount dθ_TwoIs
Each is represented by the following equation. dθ₁= A₁× Σ_f× dy (3) dθ_Two= A_Two× Σ_f× dx (4) where A₁, A_TwoIs an appropriate constant.

The luminance distribution correspondence correction means 5D calculates the correction amounts dθ ₁ and dθ ₂ determined by the above equations (3) and (4) as the vertical optical axis angle target value θ ₁ and the horizontal optical axis angle target value, respectively. Correction of the optical axis angle target values θ ₁ and θ ₂ is performed by adding to the value θ ₂ , and the corrected optical axis angle target values θ ₁ and θ ₂ are output from the optical axis angle target value calculation means 5 to the controller 7. It is supposed to be.

When the white line recognition by the image information processing means 3 is not normal, a recognition lost signal is input from the image information processing means 3 to the optical axis angle target value calculating means 5, and the recognition lost signal is input. During this time, the road curve ρ is calculated based on the information of the road center line LC with low accuracy, and therefore cannot be said to accurately represent the curvature of the road center line. Therefore, even if the output to the controller 7 calculates a lateral optical axis angle target value theta ₂ on the basis of the road curve [rho,
There is a high possibility that the optical axis control along the road center line LC cannot be performed effectively.

When the recognition lost signal is inputted from the image information processing means 3, the optical axis angle target value calculating means 5 switches the road curvature by the switching means 5A which is a functional element of the optical axis angle target value calculating means 5. Road curvature ρ calculated by calculation means 4A
From lateral optical axis angle target value theta ₂ calculated based, to switch to the calculation of the transverse optical axis angle target value theta ₂ based on the estimated road curvature calculated in substitute road curvature calculating unit 25 [rho ' Has become.

Also, since the correction angle dθ in the lane position correspondence correction means 5B is calculated based on the image information, the correction angle dθ lacks its accuracy while the recognition lost signal is being input, so that appropriate correction can be performed. Is hard to say. For this reason,
Optical axis angle target value calculating means 5, while the recognition lost signal is input, so as to stop the pair lane position-dependent correction means 5B transverse optical axis angle target value theta ₂ of the correction by.

Incidentally, due to an error between the road curvature ρ and the estimated road curvature ρ ′, when switching from the road curvature calculating means 4A to the substitute road curvature calculating means 25, the lateral optical axis angle target value θ _{2 is set.}
Can change rapidly. In such a case, the driver may feel uncomfortable.
As shown in (1), a measure is taken by performing a smoothing process by a low-pass filter 6 interposed between the optical axis angle target value calculating means 5 and the controller 7. Further, when the correction by the lane position correspondence correcting means 5B is stopped, the correction angle d
By making the magnitude of the correction angle dθ closer to 0 instead of setting θ to 0, the lateral optical axis angle target value θ ₂
To prevent abrupt changes.

Since the light distribution control device for a vehicle headlight according to the first embodiment of the present invention is configured as described above, the light distribution control process is performed, for example, as shown in FIG. First, by the preceding vehicle position calculating means 27,
Through the radar 26 detects a preceding vehicle, the position of the preceding vehicle based on information from the radar 26, i.e., calculates the deflection angle theta _F preceding vehicle and the distance L _F between the host vehicle with respect to the vehicle center line (Step S10).

After calculating the distance L _{F from} the preceding vehicle and the declination θ _F , the image information processing means 3 appropriately processes the image information in front of the vehicle input from the camera 2 and outputs the information on the road ahead. The left and right white line positions are recognized. Then, it is determined whether or not the white line position has been effectively recognized (determination of lost lane recognition) (step S20). If the white line position has been effectively recognized, the processing after step S30 is performed, and If the position of the white line cannot be recognized (that is, the white line recognition has been lost), the processing after step S60 is performed. First, when the white line position can be effectively recognized, the road curvature calculation unit 4A calculates the road curvature ρ based on the white line position image information.

That is, as shown in FIG. 2, the traveling lane estimating means 4 outputs the original image 3
The white lines 12R and 12L on A are converted into a planar view image 3B as viewed from above vertically, and the white lines 12L on the left end of the traveling lane are converted.
Based on the road centerline LC _R which may be estimated from the road center line LC _L and the traveling lane right edge of the white line 12R which can be estimated from estimates a road center line LC.

When the road center line LC is estimated,
The road curvature calculation means 4A sequentially superimposes the matching circular arc pattern 30 on the road center line LC. Then, as shown in FIG. 4B, for each of the matching arc patterns 30, the distance between the matching arc pattern 30 and the road center line LC on the horizontal line 11 in order from the bottom of the screen (dot between two points) ) Is squared and integrated, and the integrated value is compared with the integrated value in the matching circular arc pattern 30 that was previously compared at the place where the integration was performed up to the uppermost horizontal line 11. At this time, if the integrated value in the current matching arc pattern 30 is larger, the previous matching arc pattern 30 is regarded as an arc pattern that matches the road center line LC, and the curvature of this arc pattern is determined. The road curvature ρ is set (step S30).

Thus, the distance L from the preceding vehicle_F, Declination θ
_FWhen the road curvature ρ is calculated in addition to the above, the optical axis angle target value is calculated.
The means 5 calculates the optical axis angle target value θ based on these information.₁, Θ_Two
Is calculated. That is, the optical axis angle target value calculating means 5 is configured as shown in FIG.
As shown in (a) to (c), the road curvature calculating means 4A
According to the input of the road curvature ρ of the road center line LC.
An arc of curvature ρ tangent to the vertical axis at the origin (road center line L
Draw C). Then, the preceding vehicle position calculating means 5
Vehicle distance L_F, Declination θ_FIs input, FIG.
As shown in (b) and (c), L is displayed on the map._F, Θ_FTo
The corresponding point C_FAnd this point C _FGlare range around
A_FSet.

First, the optical axis angle target value calculating means 5 performs the processing shown in FIG.
(A), the intersection of the center line of the road LC and the arc L _min to take the candidate point P ₁ of the control point P, not glare source range A _F between the origin 0 to the candidate point P ₁ is present Verify that Without interfering with the glare source range A _F in the candidate point P _1, the following is the intersection of the slightly larger arc and the road center line LC than the arc L _min and the candidate point P _2, the candidate point P ₂ The interference with the glare occurrence range A _{F in} is verified. Thus, we will verify the interference between sequential glare source range A _F along the road center line LC, the interference between the glare source range A _F verifies to the intersection P _max of the road center line LC and the arc L _max If not, the road center line LC and the arc L _{max
Is set} as a control point P, and the optical axis angle target values θ ₁ and θ ₂ are set corresponding to the control point P.

Further, glare occurs along the road center line LC.
Range A_FWhen we examined the interference with_n
Point P at the intersection of the road and the center line LC_nWhen I took
The candidate point P_nAt the candidate point P from the origin 0_nFor up to
Glare occurrence range A in between_FIf there is a part that interferes with
The arc L_nArc L before_n-1And the road center line LC
Intersection P of_n-1Is a control point P, and corresponding to this control point P
Optical axis angle target value θ₁, Θ _Two(Step S above)
40).

When the optical axis angle target values θ ₁ and θ ₂ are set in this way, the lane position corresponding correction means 5B, which is a functional element of the optical axis angle target value calculation means 5, is set to the lateral shift amount calculation means 4B,
Correcting the transverse optical axis angle target value theta ₂ calculates a correction angle dθ from the equation (2) based on the lateral shift amount [Delta] Y, the yaw angle β with respect to the road center line LC that are respectively calculated by the yaw angle calculation unit 4C (Step S50).

Further, the optical axis angle target value calculating means 5 corrects the optical axis angle target values θ ₁ and θ ₂ in accordance with the illuminance of the surrounding environment by the luminance distribution correspondence correcting means 5A which is a functional element thereof. That is, the target luminance distribution that would be obtained with the optical axis angle target values θ ₁ and θ ₂ set by the optical axis angle target value calculation means 5 is compared with the actual luminance distribution detected by the camera 2. Optical axis angle target values θ ₁ and θ so that the driving lane can be illuminated efficiently.
The correction of ₂ is performed, and a series of the processing is performed as follows.

First, in the (n−1) th control cycle, the optical axis angle target values θ ₁ (n−1) and θ ₂ (n−1) output from the optical axis angle target value calculation means 5 are: It is input to the optical axis actuator 8 through the controller 7. Optical axis actuator 8
Is the optical axis angle of the headlight 9 and the optical axis angle target value θ ₁ (n−1), θ
₂ (n-1), and the headlight 9 illuminates the traveling lane ahead of the vehicle with the optical axis angle target values θ ₁ (n-1) and θ ₂ (n-1).

The traveling lane is illuminated by the headlights 9 and also by peripheral light sources other than the headlights 9, for example, street lights, and the like. Distribution occurs. Camera 2
Captures the traveling lane ahead of the vehicle as black and white image information, and detects the luminance distribution on the traveling lane by the actual luminance distribution detecting means 3A which is a functional element of the image information processing means 3.
The actual luminance distribution detecting means 3A processes the detected luminance distribution into a two-dimensional plane map (actual luminance distribution map) M _b (n) indicating the luminance of each pixel of the image detected by the camera 2, and performs a comparison process. Input to the means 29.

Then, in the next (n) -th control cycle, the optical axis angle target value calculating means 5 transmits the road curvature ρ and the preceding vehicle position information (distance L _F , declination θ _F )
Based on the optical axis angle target values θ ₁ (n) and θ ₂ (n) corrected based on the lateral shift amount ΔY and the yaw angle β, the optical axis angle target value θ ₁ ( n) and θ ₂ (n), the luminance distribution that would be obtained if the headlight 9 was irradiated is calculated, and a two-dimensional plane map (target luminance distribution map) M
Create _a (n). Then, the created target luminance distribution map M _a (n) is input to the comparison processing means 29.

The comparison processing means 29 is an actual luminance distribution detecting means.
Real brightness distribution map M obtained in 3A _b(n) and target brightness
Target luminance distribution map M obtained by distribution calculating means 5C
_a(n) is compared with the following procedure to calculate the optical axis angle target value.
Feedback to Step 5 (luminance distribution correspondence correction means 5D)
Calculate the power information. First, the comparison processing means 29
The actual luminance distribution map is created by the luminance distribution map
M_bCreated in (n) and (n-1) th control cycle
Headlight correspondence brightness distribution map M_ewith (n-1)
Calculate the brightness difference on the corresponding pixel, and calculate the calculated brightness difference.
The luminance distribution map for correction M as the luminance of the pixel_f(n)
create.

Next, in the correction amount calculating section 29B, the luminance center C _f (n) of the correction luminance distribution map M _f (n) created by the correction luminance distribution map creating section 39A, that is, on the map, The center of gravity of the map when each pixel is weighted by luminance, and the sum 輝 度_f of the luminance of the correction luminance distribution map M _f (n)
(n), that is, the sum of the luminances of all the pixels on the correction luminance distribution map M _r (n).

Further, the target luminance distribution calculating means 5
A luminance center C _a (n) of the target luminance distribution map M _a (n) input from C is calculated, and a luminance center C _f of the correction luminance distribution is calculated.
A vector C _f C _a (n) [dx (n), dy (n)] is calculated from (n) to the brightness center C _a (n) of the target brightness distribution, and the calculated sum 算出_f (n) , C _f C _a (n) [dx (n),
dy (n)] is input to the luminance distribution correspondence correction means 5D.

The luminance distribution correspondence correction means 5D outputs the vector C _f C _a (n) [dx (n) input from the comparison processing means 29.
, Dy (n)] so that the optical axis of the headlight 9 is corrected, and the sum 輝 度
The correction amount dθ ₁ (n) of the optical axis angle target values θ ₁ (n) and θ ₂ (n) is calculated from the above equation (3) so that the correction amount increases as _f (n) increases. Set dθ ₂ (n). Then, the set correction amounts dθ ₁ (n) and dθ ₂ (n) are added to the vertical optical axis angle target value θ ₁ (n) and the horizontal optical axis angle target value θ ₂ (n), respectively. To correct the optical axis angle target values θ ₁ (n) and θ ₂ (n).

The optical axis angle target value calculating means 5 calculates the corrected optical axis angle target values θ ₁ (n) and θ ₂ (n) in the current (n-th) control cycle. The values are output to the controller 7 as the values θ ₁ (n) and θ ₂ (n) (step S6).
0). The controller 7 operates the optical axis actuator 8 based on the thus obtained vertical optical axis angle target value θ ₁ and horizontal optical axis angle target value θ ₂ (step S70).

On the other hand, when the position of the white line cannot be recognized effectively, that is, in the white line recognition processing in the image information processing means 3, a state in which a certain number or more of the candidate points 15 of the white line 12 do not fall within the error range is rejected. If so,
A lost signal is input from the image information processing means 3 to the optical axis angle target value calculation means 5. The switching unit 5A, which is a functional element of the optical axis angle target value calculation unit 5, determines that the lane recognition is lost in response to the input of the lost signal (step S2).
0)), the road curvature calculating means is switched from the road curvature calculating means 4A to the substitute road curvature calculating means 25.

The substitute road curvature calculating means 25 detects the lateral acceleration G and the vehicle speed V actually acting on the vehicle 1 by the lateral acceleration sensor 21 and the vehicle speed sensor 20, respectively, based on the detected lateral acceleration G and vehicle speed V. The estimated road curvature ρ ′ is estimated from the above equation (1) (step S80). Optical axis angle target value calculating means 5, the distance between the preceding vehicle calculated by the preceding vehicle position calculating means 27 and the estimated road curvature [rho 'L _F and the polarization angle theta _F
Performing optical axis angle target value theta _1, it calculates the theta ₂ (step S90), the optical axis angle target value theta ₁ in accordance with the illuminance of the surrounding environment by the luminance distribution corresponding correction means 5A, theta ₂ of the correction based on the bets (Step S60).

When the optical axis angle target values θ ₁ and θ ₂ are calculated in this way, the controller 7 makes the optical axis angle of the headlight 9 coincide with the calculated optical axis angle target values θ ₁ and θ ₂ . The optical axis actuator 8 is operated as described above (step S7).
0). Thus, according to the present light distribution control device, the camera 2
The road center line LC is estimated from the white line on the road recognized by the image information processing means 3 based on the road image information from, and the road curvature ρ calculated based on the estimated road center line LC
Since the optical axis angle target values θ ₁ and θ ₂ are calculated according to
There is an advantage that irradiation on the traveling lane can be accurately performed regardless of the curve state of the traveling lane ahead of the vehicle.

When the driving lane is illuminated by a street light or the like, the actual luminance distribution of the driving lane obtained from the road image information from the camera 2 and the optical axis angle target values θ ₁ , θ ₂
By comparing with the target luminance distribution calculated based on the above, it is possible to detect the luminance distribution on the driving lane by the peripheral light source such as a street light, so that the part sufficiently illuminated by the peripheral light source such as the street light can be detected. Furthermore, the target values of the optical axis angles θ ₁ and θ ₂ of the headlight 9 can be adjusted so as to illuminate other dark parts without being illuminated by the headlight 9, thereby uniformly and efficiently illuminating the entire main part of the traveling lane. There is an advantage that can be.

Next, a description will be given of a light distribution control device for an automobile headlight according to a second embodiment of the present invention. The light distribution control device for a vehicle headlight according to the present embodiment is different from the light distribution control device for a vehicle headlight according to the first embodiment in the means for setting the optical axis angle target values θ ₁ and θ _2. . That is, the present light distribution control device does not correct the optical axis angle target values θ ₁ and θ ₂ calculated based on the road curvature and the preceding vehicle position information according to the peripheral illuminance as in the first embodiment. first, near the pseudo optical axis angle target value theta ₁ based on the road curvature and the preceding vehicle position information ', theta _2' set, the pseudo optical axis angle target value θ ₁ ', θ _2' and obtained from the camera information The optical axis angle target values θ ₁ and θ ₂ to be realized by the headlight are set based on the illuminance information.

The structure of the light distribution control device will be described in detail. The setting means for the pseudo optical axis angle target values θ ₁ ′ and θ ₂ ′ is the first
It has the same configuration as the setting means of the optical axis angle target values θ ₁ and θ _{2 in} the embodiment, and also has the same configuration as the detecting means of the peripheral illuminance information in the first embodiment. Therefore, description will be made here using the configuration of the first embodiment. In this light distribution control device, as shown in FIG. 9, the actual luminance distribution map M _b obtained in real luminance distribution detecting unit 3A, the road curvature [rho, the preceding vehicle position information (distance L _F, declination theta _F) , A target luminance distribution map M _a that can be obtained only by irradiating headlights with pseudo optical axis angle target values θ ₁ ′ and θ ₂ ′ set based on lane information (lateral deviation amount ΔY, yaw angle β). Are compared by the comparison processing means 39, and the optical axis angle target values θ ₁ and θ ₂ are set by the brightness distribution correspondence correction means 5D 'based on the result.

First, the target luminance distribution map based on the pseudo optical axis angle target values θ ₁ ′, θ ₂ ′
C. That is, if the pseudo optical axis angle target values θ ₁ ′ and θ ₂ ′ are given, the center position (luminance center) of the optical axis in the visual field range ahead of the vehicle can be known, and the light amount distribution from the headlight 9 Since the brightness distribution is known according to the axis angle, the luminance distribution on the traveling lane due to the irradiation of the headlight 9 can be estimated from these. Therefore, the target luminance distribution calculation means 5C calculates the light amount of the headlight 9 and the pseudo optical axis angle. A target luminance distribution is calculated based on the target values θ ₁ ′ and θ ₂ ′, and a two-dimensional plane map (hereinafter, referred to as an actual luminance distribution map) created by the actual luminance distribution detecting means 3A.
(Referred to as a target luminance distribution map). Note that the target luminance distribution map and the actual luminance distribution map respectively show the target luminance distribution and the actual luminance distribution in the same range within the visual field range in front of the host vehicle.

On the other hand, the comparison processing means 39 includes a headlight
Brightness distribution map M and actual brightness distribution obtained with only 9 light quantities
Comparison processing with the actual luminance distribution map created by the detection means 3A
It is supposed to. To explain this processing in detail,
The comparison processing means 39 includes a headlight as shown in FIG.
Brightness distribution map (peripheral light source)
Corresponding brightness distribution map) M_cFunction to create a
Luminance distribution map creation unit) 39A and headlight 9 and below
Target luminance distribution map M according to the amount of light from the outside peripheral light source_aTo
Corrected and corrected target luminance distribution map M_dFunction to create
Positive target luminance distribution map creating unit) 39B and its surroundings
Light source correspondence luminance distribution map M_cAnd correction target brightness distribution map
M _dShould be realized by the light amount of the headlight 9 based on
Brightness distribution map (headlight compatible brightness distribution map)
M_eTo calculate the correction amount of the optical axis angle target value
(Correction amount calculation unit) 39C.
Correction for brightness distribution of optical axis angle target value calculating means 5 through function
The correction amount information to be fed back to the means 5D 'is calculated.
It has become so.

First, in the peripheral light source corresponding luminance distribution map creating section 39A, the actual luminance distribution map _Mb and the headlight corresponding luminance distribution map M created in the previous control cycle are used.
calculating a luminance difference on the corresponding pixels of the _e, it is adapted to create an ambient light source corresponding luminance distribution map M _c the calculated luminance difference as the luminance of the pixel. That is, here
By subtracting the illuminance due to the irradiation of the headlights 9 from the illuminance actually illuminating the traveling lane, the deviation of the illuminance due to peripheral light sources other than the headlights 9 such as street lights is calculated.

On the other hand, the correction target luminance distribution map creating section 39
B, first, the actual luminance distribution map M _b, Target luminance distribution
Top M_aSum of each brightness, that is, all images on the map
The sum of elementary luminances is calculated. Soshi
And the calculated actual luminance distribution map M_bSum of brightness of_bWhen
Target brightness distribution map M_aSum of brightness of_aAnd the ratio (below
Bottom, total luminance ratioΣ_b/ Σ_aIs calculated, and the target brightness is calculated.
Distribution map M_aThe luminance sum ratio 画素
_b/ Σ_aMultiply by

Thus, the correction target luminance distribution map creating unit
In 39B, the target luminance distribution map M _aCorrected eyes
Standard luminance distribution map M_dIs to be created. This
Correction target luminance distribution map M_dIs the light of the headlight 9
And the amount of light from the peripheral light source
The one that shows the ideal luminance distribution to illuminate evenly
It is. The actual brightness distribution map M_bAnd target brightness distribution
Top M_aIf the pixels do not correspond one-to-one, that is,
Both maps M_b, M_aIf the resolution of the
In calculating the sum, weighting is performed according to the area of the pixel.
U.

[0086] Next, comparison processing unit 39, the correction amount calculating unit 39C, and calculates a luminance difference on the corresponding pixels of the corrected target brightness distribution map M _d and ambient light sources corresponding luminance distribution map M _c, is calculated brightness distribution map (headlights corresponding luminance distribution map) of the luminance of the pixel luminance differences M _e
Is to be created. Here, the luminance distribution of the actual traffic lane obtained by the camera 2, the luminance distribution to be achieved by the amount of light of the headlights 9 to the ideal luminance distribution as represented by the corrected target brightness distribution map M _d Perform the calculation. Then, the center of luminance C _e in the created headlight-corresponding luminance distribution map _Me , that is, the center of gravity of the map when each pixel on the map is weighted with luminance, is calculated and input to the luminance distribution-corresponding correction means 5D '. I do.

That is, the information input from the comparison processing means 39 to the luminance distribution correspondence correction means 5D 'is the luminance to be realized by the light amount of the headlight 9 calculated based on the actual luminance distribution and the target luminance distribution. a luminance center C _e of distribution, luminance distribution corresponding correction unit 5D 'is adapted to set the optical axis angle target value theta _1, theta ₂ on the basis of the luminance center C _e. Luminance distribution corresponding correction unit 5D 'preliminarily stores a correspondence map between the luminance center position of the optical axis angle target value and on the map stored in advance as the luminance center C _e input from the comparison processing unit 39 against the corresponding map, the optical axis angle target value theta ₁ corresponding to the luminance center C _e input from the comparison processing unit 39, and calculates the theta _2.

[0088] the optical axis angle calculation means 5, a luminance distribution corresponding correction unit 5D 'optical axis angle target value theta ₁ calculated in the theta _2, the optical axis angle target value theta ₁ in the present control cycle, as theta ₂ , To the controller 7. Since the light distribution control device of the automotive headlight according to the second embodiment of the present invention is configured as described above, the setting of the optical axis angle target values θ ₁ and θ ₂ according to the illuminance of the surrounding environment is performed. It is performed as follows.

First, in the (n-1) th control cycle, the optical axis angle target values θ ₁ (n-1) and θ ₂ (n-1) output from the optical axis angle target value calculating means 5 are: It is input to the optical axis actuator 8 through the controller 7. Optical axis actuator 8
Is the optical axis angle of the headlight 9 and the optical axis angle target value θ ₁ (n−1), θ
₂ (n-1), and the headlight 9 illuminates the traveling lane ahead of the vehicle with the optical axis angle target values θ ₁ (n-1) and θ ₂ (n-1).

The traveling lane is illuminated by headlights 9 and also by peripheral light sources other than the headlights 9, for example, street lights, and the like. Distribution occurs. Camera 2
Captures the traveling lane ahead of the vehicle as black and white image information, and detects the luminance distribution on the traveling lane by the actual luminance distribution detecting means 3A which is a functional element of the image information processing means 3.
The actual luminance distribution detecting means 3A processes the detected luminance distribution into a two-dimensional plane map (actual luminance distribution map) M _b (n) indicating the luminance of each pixel of the image detected by the camera 2, and performs a comparison process. Input to the means 39.

Then, in the next (n) -th control cycle, the optical axis angle target value calculating means 5 uses the target luminance distribution calculating means 5C, which is a functional element thereof, to calculate the road curvature ρ and the preceding vehicle position information (distance L). _F , declination θ _F ) and pseudo-optical axis angle target values θ ₁ (n) ′, θ ₂ (n) ′ calculated based on lane information (lateral deviation amount ΔY, yaw angle β). Pseudo-optical-axis angle target values θ ₁ (n) ′, θ
_The luminance distribution that would be obtained if the headlight 9 was irradiated with ₂ (n) 'is calculated, and a two-dimensional plane map (target luminance distribution map) M _a (n) is created. Then, the created target luminance distribution map M _a (n) is input to the comparison processing means 39.

The comparison processing means 39 is an actual luminance distribution detecting means.
Real brightness distribution map M obtained in 3A _b(n) and target brightness
Target luminance distribution map M obtained by distribution calculating means 5C
_a(n) is compared with the following procedure to calculate the optical axis angle target value.
Feedback to stage 5 (luminance distribution correspondence correction means 5D ')
The information to be calculated is calculated. First, the comparison processing means 39
The actual luminance is calculated by the side light source corresponding luminance distribution map creating unit 39A.
Distribution map M_b(n) and (n-1) th control cycle
Brightness map M for headlights created_e(n
-1) and calculate the luminance difference on the corresponding pixel with
A luminance distribution map that uses the luminance difference as the luminance of the pixel, that is,
Brightness due to peripheral light sources other than headlights 9 such as street lights
Cloth map (luminance distribution map for peripheral light source) M_c(n)
To achieve.

The correction target luminance distribution map creating section 39
B, the sum 輝 度_b of the luminance of the actual luminance distribution map M _b (n)
And calculates the luminance of the sum sigma _a target brightness distribution map M _a (n), multiplies these luminance total ratio Σ _b / Σ _a to the luminance on all the pixels on the target brightness distribution map M _a (n) To generate a corrected target luminance distribution map M _d (n). Then, the correction amount calculating unit 39C calculates the luminance difference on the corresponding pixel between the correction target luminance distribution map M _d (n) and the peripheral light source corresponding luminance distribution map M _c (n), and calculates the calculated luminance difference. A luminance distribution map (luminance distribution map corresponding to headlight) Me _e (n) is set to be the luminance of the pixel. Then, the center of luminance C _e in the created headlight-corresponding luminance distribution map M _e (n)
(n) is calculated and input to the brightness distribution correspondence correction means 5D '.

The brightness distribution correspondence correction means 5D 'performs a comparison process.
Luminance center C input from means 39 _e(n)
The corresponding processing map 39
Luminance center C input from_eOptical axis angle target value corresponding to (n)
θ₁(n), θ_Two(n) is calculated. And this calculated optical axis
Angle target value θ₁(n), θ_Two(n) to the current (n-th) control cycle
Optical axis angle target value θ₁(n), θ_Two(n) as controller
7 is output.

As described above, according to the light distribution control device of the present embodiment, light distribution control according to the illuminance of the peripheral light source can be performed similarly to the light distribution control device of the first embodiment. In the light distribution control device according to the aspect, an ideal luminance distribution (corrected target luminance distribution) for uniformly illuminating the entire main portion of the traveling path according to the luminance distribution by the peripheral light source is determined, and the light of the headlight 9 is set to the peripheral light source In addition, since the optical axis angle target values θ ₁ and θ ₂ are set so as to achieve the corrected target luminance distribution, the entire main part of the traveling lane can be illuminated more uniformly and efficiently than the light distribution control device of the first embodiment. There is an advantage that can be.

The present invention is not limited to the above-described embodiment, but can be implemented with various modifications without departing from the spirit of the present invention. For example, in the embodiments described above, the optical axis angle target value theta ₁ in accordance with the illuminance of the surrounding environment, but is performed only theta ₂ of angle correction, the optical axis angle target value theta _1, with theta ₂ of the angle correction The light amount of the headlight 9 may be adjusted according to the illuminance of the surrounding environment, or
Only the light amount of the headlight 9 may be adjusted.

In particular, as in the light distribution control device of the second embodiment described above, a luminance distribution covered by the amount of light of the headlights 9 for uniformly illuminating the entire main portion of the traveling path is determined, and this luminance distribution is achieved. In the light distribution control device that controls the light distribution as follows,
It is effective to adjust the light amount of the headlight 9. In the above embodiment, the image information from the camera 2 is used for detecting the luminance distribution on the traveling lane, but the luminance distribution on the traveling lane may be detected by a dedicated illuminometer.

[0098]

As described above in detail, according to the light distribution control device for a vehicle headlight of the present invention, the actual luminance distribution of the traveling lane detected by the actual luminance distribution detecting means and the target luminance distribution calculating means. Since the optical axis angle of the headlight is controlled based on the comparison with the target luminance distribution calculated in step (b), and the optical axis angle of the headlight is controlled so that the actual luminance distribution approaches the target luminance distribution, the traveling lane is Even when illuminated by a street light or the like, it is possible to illuminate other dark parts as a center without further illuminating a part sufficiently illuminated by a peripheral light source such as a street light with a headlight, The entire main part of the traveling lane can be illuminated uniformly and efficiently without waste, which can contribute to an improvement in the visibility of the driver.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a light distribution control device of a headlight for an automobile as a first embodiment of the present invention.

FIG. 2 is a diagram illustrating image processing for driving lane recognition according to the first embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating traveling lane recognition according to the first embodiment of the present invention in the order of (a) to (f).

FIG. 4 is an explanatory diagram for describing calculation of a road curvature of a driving lane according to the first embodiment of the present invention;
(A) is a figure which shows the circular arc pattern for a collation for road curvature calculation, (b) is a figure which shows a collation example.

FIG. 5 is an explanatory diagram for describing calculation of a lateral shift amount and a yaw angle according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram for describing calculation of an optical axis angle target value based on a preceding vehicle position and a road curvature according to the first embodiment of the present invention, where (a) illustrates a case where there is no preceding vehicle; , (B) shows the case where the preceding vehicle exists on the traveling lane in which the host vehicle travels, and (c) shows the case where the preceding vehicle exists on the inner adjacent lane.

FIG. 7 is an explanatory diagram for describing correction of an optical axis angle target value according to a luminance distribution on a traveling road according to the first embodiment of the present invention.

FIG. 8 is a flowchart for explaining the operation of the light distribution control device for a vehicle headlight according to the first embodiment of the present invention.

FIG. 9 is an explanatory diagram for describing correction of an optical axis angle target value according to a luminance distribution on a traveling road according to a second embodiment of the present invention.

[Explanation of symbols]

 2 Camera 3 Image information processing means 3A Actual luminance distribution detecting means 4 Running lane estimating means 4A Road curvature calculating means 5 Optical axis angle target value calculating means 5C Target luminance distribution calculating means 5D, 5D 'Luminance distribution correspondence correcting means 7 Controller (control Means) 8 optical axis actuator 9 headlight 26 radar 27 preceding vehicle position calculating means 29, 39 comparison processing means

Claims (1)

[Claims] 1. A light distribution control device for an automobile headlight for adjusting an optical axis angle of a headlight via an optical axis actuator, wherein a target luminance distribution of a traveling path in front of a vehicle illuminated by the headlight is obtained. A target luminance distribution calculating means for calculating; an actual luminance distribution detecting means for detecting an actual luminance distribution of the traveling road; a target luminance distribution calculated by the target luminance distribution calculating means and detected by the real luminance distribution detecting means. An optical axis angle target value calculating means for calculating an optical axis angle target value that brings the actual luminance distribution closer to the target luminance distribution based on the comparison with the actual luminance distribution. A light distribution control device for an automobile headlight, comprising: a control unit that controls the optical axis actuator so as to be equal to the optical axis angle target value calculated by the target value calculation unit.