JPH11208366A - 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 that a traveling lane ahead of the traveling direction of the vehicle can be irradiated without causing glare to a preceding vehicle. A preceding vehicle detecting means detects a preceding vehicle traveling ahead of the own vehicle, and a preceding vehicle position calculating means calculates a relative position of the preceding vehicle with respect to the own vehicle based on the detected information. The road curvature calculating means 4
A is used to calculate the road curvature of the traveling lane in which the host vehicle is traveling. The optical axis angle target value calculating means 5 calculates the vertical optical axis angle based on the relative position of the preceding vehicle to the own vehicle calculated by the preceding vehicle position calculating means 27 and the road curvature calculated by the road curvature calculating means 4A. The control means 7 calculates the target value and the target value of the lateral optical axis angle,
Is adjusted so that the vertical optical axis angle and the horizontal optical axis angle of the headlight 9 become equal to the calculated vertical optical axis angle target value and horizontal optical axis angle target value.

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 more particularly, to an optical axis of a headlight according to a curve condition of a road or a position of a preceding vehicle. 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 controlling the light distribution in the horizontal direction, Japanese Patent Application Laid-Open No. 6-206491 discloses a technique for controlling a horizontal optical axis angle of a headlight corresponding to a curve (hereinafter referred to as a first conventional technique). )
Is disclosed. 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.

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

[0005]

By the way, in driving at night, the driver effectively illuminates the road surface ahead of the host vehicle and tries to obtain as much external information as possible. Hopefully it can be irradiated to the distant traveling lane. In other words, by adjusting the horizontal optical axis angle and the vertical optical axis angle corresponding to the curve of the road ahead, even if the road ahead is a curved road, it is possible to irradiate as far as possible on the road ahead. Want to.

However, when a preceding vehicle is present ahead, if the optical axis of the headlight is set so as to irradiate the vehicle far away, the light of the headlight of the own vehicle is reflected on the rearview mirror of the preceding vehicle, so-called glare. This may cause glare to the driver of the preceding vehicle and adversely affect driving. For this reason, it is desired that the optical axis angle of the headlight is adjusted along the traveling lane within a range that does not cause glare in the preceding vehicle.

However, in the first prior art,
Since the horizontal optical axis angle of the headlights is controlled according to the curve, it is not possible to effectively illuminate this road surface even if the road surface ahead of the vehicle on which the vehicle is going is a curved road. Although it is possible, since the vertical control of the optical axis is not actively performed, the setting of the optical axis angle is performed irrespective of the existence of the preceding vehicle, and the possibility that glare occurs in the preceding vehicle is inevitable.

On the other hand, in the second prior art, the optical axis angle in the vertical direction can be controlled according to the distance from the preceding vehicle, but the optical axis angle in the horizontal direction is not controlled. The optical axis angle cannot be controlled correspondingly. In addition, although a light blocking member that restricts irradiation to the oncoming vehicle is provided, as for the preceding vehicle, since the optical axis angle is controlled only for the preceding vehicle in the traveling lane in which the own vehicle travels,
Particularly on a curved road, there is a possibility that glare may be generated in a preceding vehicle traveling in the adjacent lane.

Further, in order to prevent glare from an oncoming vehicle by blocking light, a light-blocking member and a mechanism for driving the light-blocking member are required in addition to the optical axis adjusting mechanism, which tends to increase costs. The present invention has been made in view of the above-described problems, and provides a light distribution control device for a headlight for an automobile, which can irradiate a traveling lane ahead of a traveling direction of a vehicle without causing glare to a preceding vehicle. The purpose is to provide.

[0010]

Therefore, in the light distribution control device for a headlight for an automobile according to the present invention, the preceding vehicle detecting means detects a preceding vehicle traveling ahead of the own vehicle.
Based on this detection information, the preceding vehicle position calculating means calculates the relative position of the preceding vehicle with respect to the own vehicle. The road curvature calculating means calculates the road curvature of the traveling lane in which the host vehicle is traveling.

The optical axis angle target value calculating means calculates the vertical optical axis angle based on the relative position of the preceding vehicle to the own vehicle calculated by the preceding vehicle position calculating means and the road curvature calculated by the road curvature calculating means. A target value and a lateral optical axis angle target value are calculated, and the control means determines the vertical optical axis angle and the lateral optical axis angle of the headlight through the optical axis actuator, and calculates the calculated vertical optical axis angle target value and the calculated vertical optical axis angle. Adjustment is made to be equal to the lateral optical axis angle target value.

Thus, the optical axis of the headlight is adjusted along the traveling lane without causing glare in the preceding vehicle.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 8 show a light distribution control device for a headlight for an automobile according to an embodiment of the present invention. . 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.

In addition, the light distribution control device may calculate road curvature based on a lateral acceleration G and a vehicle speed V of the vehicle, in addition to a road curvature calculation unit 4A that calculates based on white line position image information. A substitute road curvature calculating means 25 for calculating a road curvature (estimated road curvature ρ ') is provided. The road curvature calculating means 4A includes a lateral displacement amount calculating means 4B for calculating a lateral displacement amount ΔY of the traveling lane of the own vehicle from the reference position, and a yaw angle calculating means 4C for calculating a yaw angle β of the own vehicle relative to the traveling lane It 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.

Further, the present light distribution control device uses a radar (preceding vehicle detecting means) 26 as detecting means for detecting the presence of a preceding vehicle ahead of the own vehicle in order to recognize the relative position of the preceding vehicle with respect to the own vehicle. When appropriately processed and the relative position of the preceding vehicle with respect to the vehicle the radar information from the radar 26, i.e., a deflection angle theta _F of the preceding vehicle with respect to the distance L _F and the vehicle center line between the host vehicle and the preceding vehicle is calculated And a preceding vehicle position calculating means 27.

The light distribution control device calculates the road curvature ρ calculated by the road curvature calculation means 4A or the estimated road curvature ρ 'calculated by the substitute road curvature calculation means 25, and calculates the preceding vehicle position calculation means 27. Distance L _F between the subject vehicle and the preceding vehicle, and the deviation θ _F of the preceding vehicle with respect to the subject vehicle
An optical axis angle target value calculating means 5 for calculating a vertical optical axis angle target value θ ₁ and a horizontal optical axis angle target value θ _{2 based} on the optical axis actuator 8 for moving the optical axis of the headlight 9. ,
The optical axis angle of the headlight 9 is determined by the target value
And 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 in the above.

The image information processing means 3, the traveling lane estimating means 4 (the road curvature calculating means 4A, the lateral displacement amount calculating means 4)
B, yaw angle calculation means 4C), substitute road curvature calculation means 2
5, the preceding vehicle position calculating means 27, the optical axis angle target value calculating means 5, and the controller 7 are configured as an electronic control unit including a CPU, 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. First, as shown in FIG. 2, the image information processing means 3 takes in the original image 3A from the camera 2, extracts a road white line from the original image 3A, and looks at the extracted image of the road white line from above vertically. The image is converted into a planar view image 3B as described 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 takes in 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 uses the image information to display the image in the vertical direction on the 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.

Then, for each data of each horizontal line 11, peaks of the differential values appear in the order of plus and minus from the left, and the interval between the 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.

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 cases where the white line 12 cannot be recognized as described above include a case where the road surface is wet and a case where a large number of puddles are present. In such a case, since the light is easily reflected, the luminance of the road surface increases, and the luminance difference between the white line 12 and the white line 12 becomes small. Therefore, it is difficult to distinguish the white line 12 from the normal road surface. Further, even when the white line 12 is broken or unclear on the way, or when there is a display or an object close to white in the vicinity of the white line 12, the white line may not be recognized.

In the traveling lane estimating means 4, the white lines 12R, 12R on the original image 3A recognized in each recognition cycle are
The L is converted into a 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.
Is calculated.

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.

Lateral deviation amount calculating means 4B, 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 the 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.

It should be noted that θ in FIGS._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 performs the processing 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 .

[0038] 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 setting of the optical axis angle target values θ ₁ and θ ₂ is performed in this manner. In actual traveling, the vehicle is not necessarily traveling 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 determines the target optical axis angle θ ₂ , particularly the lateral optical axis angle target value θ _2, from the optical axis angle target values θ ₁ and θ ₂ calculated as described above. The correction is performed by the correction means 5A.

The optical axis angle target value correcting means 5A calculates the lateral displacement ΔY of the vehicle calculated by the lateral displacement calculating means 4B and the yaw angle which the vehicle calculates with the yaw angle calculating means 4C with respect to the road center line LC. based on the beta, determining a correction angle dθ of the transverse optical axis angle target value theta _2. That is, the correction angle dθ is represented by the following equation. dθ = β−ΔY / L (2) Then, the optical axis angle target value correcting means 5A calculates the correction angle dθ.
The by dividing the lateral optical axis angle target value theta _2, has to do the correction according to the lateral deviation and inclination with respect to the road center line LC of the vehicle.

The optical axis angle target value calculating means 5 operates in this manner.
Lateral optical axis angle target value θ _TwoAnd the vertical optical axis angle
Target value θ₁To the controller 7
I have. By the way, the white line recognition by the image information processing means 3
In the event of a malfunction, the image information processing means 3 calculates the optical axis angle target value.
The recognition lost signal is input to the output means 5, and this recognition
The road curve ρ has low accuracy while the
Is calculated based on the information of the road center line LC
It is hard to say that it represents the curvature of the road centerline. did
Therefore, based on this road curve ρ, the lateral optical axis angle target value
θ_TwoIs calculated and output to the controller 7,
Possibility of not being able to control the optical axis along the road center line LC
Good.

Then, when the recognition lost signal is input from the image information processing means 3, the optical axis angle target value calculation means 5 switches the road curvature by the switching means 5B which is a functional element of the optical axis angle target value calculation 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.

Further, the correction angle dθ in the optical axis angle target value correcting means 5A is calculated on the basis of the image information, and thus lacks its accuracy while the recognition lost signal is input.
It is hard to say that appropriate corrections can be made. Therefore, the optical axis angle target value calculating means 5, while the recognition lost signal is input, so as to cancel the transverse optical axis angle target value θ ₂ corrected by the optical axis angle target value correcting means 5A ing.

Note that, 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.
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. Also, when the correction by the optical axis angle target value correction unit 5A is stopped, the magnitude of the correction angle dθ is gradually reduced to 0 instead of suddenly setting the correction angle dθ to 0. the abrupt change in the axial angle target value theta ₂ so as to prevent.

Since the light distribution control device for a vehicle headlight according to one embodiment of the present invention is configured as described above, the light distribution control process is performed as shown in FIG. 7, for example. First, 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., the preceding vehicle and the distance L _F between the preceding vehicle and the subject vehicle Declination θ _{F with} respect to own vehicle center line
Is calculated (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 (step S2).
0). At this time, if the white line position can be effectively recognized, the processing of steps S30 to S50 is performed, and if the white line position cannot be effectively recognized (that is, the white line recognition lost state).
Then, the processing of steps S70 to S80 is performed.

First, when the white line position can be effectively recognized, the road curvature calculating means 4 is used based on the white line position image information.
A is used to calculate the road curvature ρ (step S30). That is, as shown in FIG. 2, the traveling lane estimating means 4 outputs the white line 12 on the original image 3A recognized by the image information processing means 3.
R and 12L are converted into a planar view image 3B as viewed from vertically above, and the road center line LC _L which can be estimated from the white line 12L at the left end of the driving lane and the road center line LC which can be estimated from the white line 12R at the right end of the driving lane. Based on _R , the road center line L
Estimate C.

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. It is assumed that the road curvature is ρ.

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 (step S40). That is, the optical axis angle target value calculation
As shown in FIGS. 6 (a) to 6 (c), the output unit 5 outputs a road curve.
Input of the road curvature ρ of the road center line LC from the rate calculating means 4A.
Depending on the force, a circle of curvature ρ tangent to the vertical axis at the origin on the map
Draw an arc (road center line LC). Then, the preceding vehicle position calculation
Distance L of the preceding vehicle from the exit means 5_F, Declination θ_FIs entered
Then, as shown in FIGS. 6B and 6C, L is displayed on the map.
_F, Θ_FPoint C according to_FAnd this point C _FAround
Rare generation range 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 _TwoSet.

Thus, the optical axis angle target value θ₁, Θ_TwoIs set
Then, the optical axis which is a functional element of the optical axis angle target value calculating means 5
The angle target value correction means 5A includes a lateral displacement amount calculation means 4B, a yaw
Road center line L calculated by angle calculating means 4C
Based on the lateral shift amount ΔY with respect to C and the yaw angle β,
The correction angle dθ is calculated from the equation (2), and the lateral optical axis angle target value θ is calculated.
_TwoIs corrected (step S50).

[0055] The controller 7, thus activating the optical axis actuator 8 on the basis of the lateral optical axis angle target value theta ₂ obtained and the longitudinal optical axis angle target value theta ₁ (step S6
0). On the other hand, when the white line position cannot be effectively recognized in step S20, that is, in the white line recognition process in the image information processing means 3, a state where more than a fixed number of the candidate points 15 of the white line 12 does not fall within the error range is rejected. In this case, 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 5B, which is a functional element of the optical axis angle target value calculation unit 5, switches the road curvature calculation unit from the road curvature calculation unit 4A to the substitute road curvature calculation unit 25 in response to the input of the lost signal (step S20). ).

The substitute road curvature calculating means 25 detects the lateral acceleration G and the vehicle speed V actually acting on the vehicle 1 with the lateral acceleration sensor 21 and the vehicle speed sensor 20, respectively, and based on the detected lateral acceleration G and vehicle speed V. The estimated road curvature ρ ′ is estimated from the above equation (1) (step S70). 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
Then, the optical axis angle target values θ ₁ and θ ₂ are calculated based on the above (Step S80).

That is, the optical axis angle target value calculating means 5 replaces the input of the road curvature ρ from the road curvature calculating means 4A with the substitute road curvature calculating means 2 in the processing of step S40.
5 in accordance with the input of the estimated road curvature ρ ′, the arc of the curvature ρ ′ tangent to the vertical axis at the origin on the map (road center line LC)
And the distance L from the preceding vehicle position calculating means 5
_F, set the glare source range A _F on the map in response to the input of the polarization angle theta _F.

Then, from the intersection with the arc _Lmin , the arc L
_It is verified that a straight line connecting the origin and the candidate point P _k on the road center line LC does not interfere with the glare occurrence range _AF along the road center line LC up to the intersection with the _max. The intersection of the line LC and the arc L _min is defined as a control point P, and if there is any interference on the way, the arc just before that and the road center line LC
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.

When the white line recognition of the image information processing means 3 is not good, the correction angle dθ in the optical axis angle target value correction means 5A is also calculated based on the image information, and thus lacks accuracy, and appropriate correction is not performed. Since it is difficult to say that the correction can be performed, the optical axis angle target value calculating means 5 corrects the lateral optical axis angle target value θ ₂ by the optical axis angle target value correcting means 5A while the recognition lost signal is being input. To stop. Then, when the correction by the optical axis angle target value correcting means 5A is stopped, the magnitude of the correction angle dθ is gradually made closer to 0, instead of suddenly setting the correction angle dθ to 0.

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 S6).
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 it is possible to accurately irradiate the road center line irrespective of the curve situation of the traveling lane ahead of the vehicle.

When a preceding vehicle exists in front of the vehicle, the preceding vehicle position calculating means 27 calculates the position of the preceding vehicle with respect to the own vehicle based on the radar information from the radar 26, and calculates the calculated preceding vehicle. The optical axis angle target value θ is compared with the position and the road center line LC estimated from the image information.
_{Since 1} and θ ₂ are calculated, there is an advantage that the optical axis angle target value of the headlight 9 can be controlled so as to irradiate the farthest point on the road center line without causing glare to the preceding vehicle. .

The detection of the position of the preceding vehicle is not limited to the detection by the radar 26 as in the present embodiment, but may be calculated based on road image information ahead of the vehicle obtained by the camera 2. That is, as shown in FIG. 8, when the camera 2 captures black-and-white image information in a range in front of the vehicle,
The tail lamps 40R and 40L of the preceding vehicle 40 are much higher in brightness than a normal road surface, and the white lines 12R and 12L.
Has a very high luminance. For this reason, by performing binarization processing using a certain fixed luminance as a threshold value, the tail lamps 40R and 40L of the preceding vehicle 40 can be recognized. Therefore, thus recognized left and right tail lights 40R, the center position of the preceding vehicle center 40C of 40L regarded, by measuring the position with respect to the vehicle 1 of this preceding vehicle center 40C, the distance L _F between the subject vehicle 1 The declination θ _F with respect to the vehicle center line can be calculated.

Further, the position and orientation of the host vehicle with respect to the road center line, that is, the lateral shift amount ΔY and the yaw angle β can be grasped based on the image information, so that the optical axis angle target calculated based on the road curvature ρ is obtained. The values θ ₁ and θ ₂ are defined as these lateral shift amounts Δ
By correcting according to the Y and yaw angles β, the optical axis angle of the headlight 9 can be controlled so as to always accurately irradiate the road center line regardless of the position and orientation of the vehicle with respect to the road center line. There is.

Further, when the white line recognition in the image information processing means 3 is not normal, for example, when the road surface is wet,
When a large number of puddles exist on the road surface, or when the white line is broken or unclear on the way, the lateral acceleration G is used instead of the road curvature ρ calculated by the road curvature calculation unit 4A based on the image information. The estimated road curvature ρ ′ calculated by the substitute road curvature calculation means 25 based on the vehicle speed V and the vehicle speed V is substituted for the calculation of the optical axis angle target values θ ₁ and θ _2. This makes it possible to prevent the driver from feeling uncomfortable due to discontinuity.

In the substitute road curvature calculating means 25, the lateral acceleration G is directly detected by the lateral acceleration sensor 21.
It is also possible to calculate the lateral acceleration G based on the steering angle α when the driver steers the steering wheel, and calculate the estimated road curvature ρ ′ based on the calculated lateral acceleration G. That is, a steering angle sensor 2 is attached to a steering shaft (not shown) of the vehicle.
The steering angle α of the steering wheel is detected by the steering angle sensor 22, and the lateral acceleration G is calculated by the following equation together with the vehicle speed V detected by the vehicle speed sensor 20.

G = [α / (n × g)] × (V ² / wb) / (1 + a × V ² ) (3) Then, this equation (3) is substituted into the above equation (1). Thus, the estimated road curvature ρ ′ is calculated. Where n,
g, wb, and a are fixed values indicating the gear ratio, the gravitational acceleration, the wheelbase, and the stability factor, respectively. Furthermore, the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the spirit of the present invention.

For example, in the above-described embodiment, when setting the optical axis angle target values θ ₁ and θ ₂ , as shown in FIGS. Assuming that the amount is 0, that is, the vehicle is traveling on the road center line CL of the traveling lane, an arc corresponding to the road center line CL is drawn on the map so as to be in contact with the vehicle center line, A control point (irradiation target point) P is set by taking an irradiation target candidate point _Pk on this arc, and the optical axis angle target values θ ₁ and θ ₂ set based on the control point P are set to the yaw angle and the lateral deviation. Although the correction is made by the amount, the yaw angle and the amount of lateral displacement of the host vehicle may be taken into consideration from the stage of setting the control point P.

That is, when an arc corresponding to the road center line CL is drawn on the map, the position and angle of the arc are corrected based on the yaw angle and the amount of lateral displacement of the own vehicle, so that the center of the road drawn on the map is corrected. The arc corresponding to the line CL corresponds to the relative relationship between the actual vehicle and the road center line CL. If the control point P is set by taking the candidate point _Pk based on such an arc, and the optical axis angle target values θ ₁ and θ ₂ are set based on the control point P, the optical axis angle target value θ ₁ it can be used as it is controlled without subsequently correcting the theta _2.

In this embodiment, the road curvature ρ of the road center line is calculated based on the image information obtained by the camera 2. For example, the information transmission for issuing the road curvature information of the road center line to the road side. Means for receiving the road curvature information on the vehicle side to obtain the road curvature information by road-to-vehicle communication and obtain the optical axis angle target value θ ₁ ,
θ ₂ may be set.

The transmission of information in this case may be by radio waves. However, road curvature information is included in a white line on the road side, and the image information captured by the camera 2 of the vehicle 1 is processed in the process of processing the image information. The optical axis angle target values θ ₁ and θ ₂ may be set based on the road curvature information obtained by extracting the road curvature information. Further, when a magnetic nail is provided on the road side, road curvature information is included in the magnetic nail, and the road curvature information is extracted from the magnetic information in the process of processing the magnetic information captured by the magnetic sensor on the vehicle side. Thus, the optical axis angle target values θ ₁ and θ ₂ may be set.

Further, the road position information is stored in advance in the storage means, and the position information of the vehicle is detected by GPS or autonomous navigation. Information on the driving lane for the vehicle may be obtained. In this case,
Road-to-vehicle communication is not always possible, and road curvature information may not be obtained from the road side depending on the road condition. In such a case, the lateral acceleration G or the vehicle speed V acting on the vehicle as described above is used. Can be dealt with by estimating the road curvature from.

Further, in detecting the position of the preceding vehicle,
In the present embodiment, based on the radar information by the radar 26 is calculated and a deviation angle theta _F and distance L _F of the preceding vehicle with respect to the vehicle, for example, information transmission means for emitting the vehicle information to the front and rear of the vehicle And receiving means for receiving the information, and the mutual positions may be grasped by inter-vehicle communication. In this case, the optical axis angle target values θ ₁ and θ ₂ may be set more accurately by including the information on the occurrence of glare such as the size of the vehicle and the height of the rearview mirror in the inter-vehicle communication information. .

[0073]

As described above in detail, according to the light distribution control device for a vehicle headlight according to the present invention, the vertical light is controlled in accordance with the road curvature of the traveling lane ahead of the vehicle calculated by the road curvature calculation means. Since the target value of the axial angle and the target value of the lateral optical axis angle are set, it is possible to irradiate the road center line accurately regardless of the curve situation.

When a preceding vehicle exists in front of the vehicle, the preceding vehicle position calculating means calculates the position of the preceding vehicle with respect to the own vehicle based on the detection information from the preceding vehicle detecting means. Since the target value of the vertical optical axis angle and the target value of the horizontal optical axis angle are calculated based on the vehicle position and the road curvature calculated by the road curvature calculation means, the maximum value on the traveling lane without causing glare in the preceding vehicle. The vertical optical axis angle and the horizontal optical axis angle of the headlight can be controlled so as to irradiate a distant point.

[Brief description of the drawings]

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

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

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

4A and 4B are explanatory diagrams for describing calculation of a road curvature of a traveling lane, where FIG. 4A is a diagram illustrating a matching arc pattern for calculating a road curvature, and FIG. 4B is a diagram illustrating a matching example; .

FIG. 5 is an explanatory diagram for describing calculation of a lateral shift amount and a yaw angle.

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;
(A) is when there is no preceding vehicle, (b) is when there is a preceding vehicle on the traveling lane in which the own vehicle travels, (c)
Indicates a case where the preceding vehicle exists on the adjacent lane inside the curve.

FIG. 7 is a flowchart for explaining the operation of the light distribution control device for a vehicle headlight as one embodiment of the present invention.

FIG. 8 is an explanatory diagram for describing calculation of a relative position of a preceding vehicle with respect to a host vehicle based on image information.

[Explanation of symbols]

 2 Camera 3 Image information processing means 4 Running lane estimating means 4A Road curvature calculating means 4B Lateral deviation amount calculating means 4C Yaw angle calculating means 5 Optical axis angle target value calculating means 5A Optical axis angle target value correcting means 5B Switching means 6 Low pass filter 7 Controller (control means) 8 Optical axis actuator 9 Headlight 20 Lateral acceleration sensor 21 Vehicle speed sensor 22 Steering angle sensor 25 Substitute road curvature calculating means 26 Radar (preceding vehicle detecting means) 27 Leading vehicle position calculating means LC Road center line

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 according to a curve situation of a traveling lane in front of a host vehicle, comprising: Preceding vehicle detecting means for detecting the presence of a preceding vehicle; preceding vehicle position calculating means for calculating a relative position of the preceding vehicle with respect to the own vehicle based on detection information of the preceding vehicle detecting means; Road curvature calculating means for calculating the road curvature of the traveling lane; longitudinal light based on the relative position of the preceding vehicle calculated by the preceding vehicle position calculating means and the road curvature calculated by the road curvature calculating means. An optical axis angle target value calculating means for calculating an axial angle target value and a lateral optical axis angle target value; and a vertical optical axis angle and a lateral optical axis angle of the headlight are calculated by the optical axis angle target value calculating means. The vertical optical axis angle Characterized in that and a control means for controlling the optical axis actuator so as to be equal to the value and said lateral optical axis angle target value, light distribution control apparatus for an automobile headlight.