WO2024218812A1 - Light distribution control device, light distribution control system, and light distribution control method - Google Patents

Abstract

The present invention comprises: an irradiation target presence/absence determination unit (11) that determines the presence or absence of an irradiation target present in front of a vehicle (100) on the basis of first vehicle exterior information; a brightness detection unit (12) that detects the brightness in front of the vehicle (100) on the basis of second vehicle exterior information; an irradiation necessity determination unit (13) that, when the irradiation target presence/absence determination unit (11) has determined that the irradiation target is present in front of the vehicle (100), determines whether the irradiation of a target area with light is necessary on the basis of the brightness in front of the vehicle (100); an irradiation condition determination unit (14) that determines an irradiation condition with light for headlights (4) on the basis of the determination result by the irradiation necessity determination unit (13) of whether or not the irradiation of the target area with light is necessary; and a light distribution control unit (15) that controls the headlights (4) in accordance with the irradiation condition.

Description

Light distribution control device, light distribution control system, and light distribution control method

This disclosure relates to a light distribution control device, a light distribution control system, and a light distribution control method.

　Conventionally, in the light distribution control of vehicle headlights, when there is an object (hereinafter referred to as the "illumination object") in front of the vehicle that needs to be illuminated by the headlights, such as a person, there is known a technology for illuminating the area (hereinafter referred to as the "target area") in which the illumination object is present (for example, Patent Document 1).

JP 2012-40950 A

Even if there is an illumination target in front of the vehicle, illumination may not always be necessary depending on the brightness of the surroundings of the illumination target.
Conventional techniques have had the problem that they are unable to control the light distribution of headlights in a way that takes this into account.

This disclosure has been made to solve the above problems, and aims to provide a light distribution control device that can control the light distribution of headlights in a vehicle while taking into account the brightness of the area around the target to be illuminated.

The light distribution control device according to the present disclosure includes an irradiation target presence/absence determination unit that determines the presence or absence of an irradiation target present in front of the vehicle based on first external information related to objects present around the vehicle, a brightness detection unit that detects the brightness ahead of the vehicle based on second external information for determining the brightness ahead of the vehicle, an illumination necessity determination unit that determines whether or not it is necessary to irradiate the target area where the irradiation target exists based on the brightness ahead of the vehicle detected by the brightness detection unit when the irradiation target presence/absence determination unit determines that an irradiation target exists ahead of the vehicle, an illumination condition determination unit that determines the illumination conditions for the headlights based on the determination result by the illumination necessity determination unit as to whether or not it is necessary to irradiate the target area with light, and a light distribution control unit that controls the headlights according to the illumination conditions determined by the illumination condition determination unit.

According to this disclosure, it is possible to perform light distribution control that takes into account the brightness around the target to be illuminated.

1 is a diagram illustrating a configuration example of a light distribution control device according to a first embodiment. 11 is a diagram for explaining a distance X, a distance Y, a left end point Pl of the irradiation target, and a right end point Pr of the irradiation target, which are acquired by an irradiation target presence/absence determining unit in the first embodiment. FIG. 4 is a diagram for explaining an example of a method in which a brightness detection unit detects the brightness ahead of a vehicle in the first embodiment. FIG. 10 is a diagram for explaining an example of the range of a target region determined as an irradiation condition by an irradiation condition determination unit in the first embodiment. FIG. 4 is a flowchart for explaining the operation of the light distribution control device according to the first embodiment. 6 is a flowchart for explaining details of step ST2 in FIG. 5 . 6 is a flowchart for explaining details of step ST3 in FIG. 5 . 6 is a flowchart for explaining details of step ST4 in FIG. 5 . 9A and 9B are diagrams illustrating an example of a hardware configuration of the light distribution control device according to the first embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.
Embodiment 1.
FIG. 1 is a diagram showing an example of the configuration of a light distribution control device 1 according to the first embodiment.
In the first embodiment, it is assumed that the light distribution control device 1 is mounted on a vehicle 100 (see Figs. 2 and 4 described later).

The light distribution control device 1 determines whether or not there is an object (hereinafter referred to as an "irradiation object") that needs to be irradiated with the light of the headlights 4 in front of the vehicle 100. When it is determined that an irradiation object exists, the light distribution control device 1 performs light distribution control of the headlights 4 in consideration of the brightness of an area (hereinafter referred to as an "object area") in which the irradiation object exists. In other words, the irradiation object is an object that is estimated to be a visual target by the occupant of the vehicle 100. In the first embodiment, the occupant of the vehicle 100 who visually recognizes the irradiation object is assumed to be the driver. In addition, in the first embodiment, the irradiation object is assumed to be a person such as a pedestrian. Note that this is merely an example, and the occupant of the vehicle 100 who visually recognizes the irradiation object may include, for example, an occupant other than the driver. In addition, the irradiation object may be, for example, a moving object other than a person, or a stationary object such as a fallen object on the path of the vehicle 100, as long as it is an object that is estimated to be a visual target by the occupant of the vehicle 100.
In the first embodiment, the light distribution control of the headlight 4 performed by the light distribution control device 1 is assumed to be, specifically, the control of the illumination range of the light emitted by the headlight 4 .

When a driver inputs an instruction to start light distribution control of the headlights 4 in a dark place such as an urban area at night or a parking lot at night, the light distribution control device 1 performs the above-described light distribution control of the headlights 4. The instruction to start light distribution control is assumed to be, for example, an instruction to turn on automatic high beam control. For example, the driver issues an instruction to start light distribution control by pressing a switch for turning on automatic high beam control provided in the vehicle 100.
In addition, the light distribution control of the headlights 4 performed by the light distribution control device 1 assumed in the first embodiment, in other words, the control of the irradiation range of the light emitted by the headlights 4, is basically, more specifically, the control of turning on or off the high beams. When the vehicle 100 is running at night, it is necessary that the low beams are turned on. The control of turning on the low beams when the vehicle 100 is running at night is performed separately.

The light distribution control device 1 is connected to an outside object detection device 2 , an outside brightness detection device 3 , and a headlight 4 .
The light distribution control device 1 and the headlight 4 constitute a light distribution control system 10.
The outside object detection device 2 , the outside brightness detection device 3 , and the headlights 4 are provided in the vehicle 100 .

The vehicle exterior object detection device 2 detects objects present around the vehicle 100. Note that the vehicle exterior object detection device 2 constantly detects objects present around the vehicle 100, for example, when the power of the vehicle 100 is turned on.
The vehicle exterior object detection device 2 is, for example, a radio wave sensor including a millimeter wave radar, or an optical sensor including a LiDAR (Light Detection and Ranging). In the first embodiment, the vehicle exterior object detection device 2 is assumed to be a millimeter wave radar. In the following description, the vehicle exterior object detection device 2, more specifically, the millimeter wave radar, will be described as a "radio wave sensor".

The radio wave sensor acquires information about objects present around the vehicle 100 (hereinafter referred to as “object information”).
The radio wave sensor transmits radio waves such as millimeter waves around the vehicle 100 and receives the reflected waves that are reflected by an object. The radio wave sensor can detect the presence of an object associated with the reflected wave, the distance to the object, the shape of the object, etc., based on the time from when the radio waves are transmitted to when the reflected wave is received. The object information acquired by the radio wave sensor includes information on the presence of the object, the distance to the object, the shape of the object, etc. Note that the radio waves are irradiated to a plurality of areas in a predetermined range around the vehicle 100, and the object information includes information on the presence of the object, the distance to the object, the shape of the object, etc., for the number of areas irradiated with the radio waves.
The radio wave sensor does not have to be composed of only one sensor, but may be composed of a combination of a plurality of sensors.
The radio wave sensor outputs object information to the light distribution control device 1 .
In the first embodiment, the object information is information for the light distribution control device 1 to determine the presence or absence of an illumination target present in front of the vehicle 100. In the first embodiment, the object information is also referred to as "first outside-vehicle information." Details of the light distribution control device 1 will be described later.

The vehicle exterior brightness detection device 3 detects the brightness ahead of the vehicle 100. Note that the vehicle exterior brightness detection device 3 constantly detects the brightness ahead of the vehicle 100, for example, when the power of the vehicle 100 is turned on.
In the first embodiment, it is assumed that the vehicle exterior brightness detection device 3 is, for example, a visible light camera. In the following description, the vehicle exterior brightness detection device 3 will be described as a "visible light camera."
The visible light camera captures an image ahead of the vehicle 100. The visible light camera is, for example, a monocular camera or a stereo camera.
The visible light camera outputs a captured image of the area ahead of the vehicle 100 (hereinafter referred to as a “vehicle front image”) to the light distribution control device 1 .
In the first embodiment, the vehicle front image is information for the light distribution control device 1 to determine the brightness ahead of the vehicle 100. In the first embodiment, the vehicle front image is also referred to as "second outside information."

The headlight 4 is a lighting device that illuminates the area ahead of the vehicle 100 .
The headlight 4 is a typical headlight that is configured, for example, by a driving headlight (high beam) and a passing headlight (low beam), and therefore a detailed configuration example will not be described.
In the first embodiment, the high beam is assumed to be of a variable light distribution type (ADB (Adaptive Driving Beam)) capable of controlling the light distribution pattern. The ADB is capable of blocking light from a specific area while illuminating other areas. The ADB controls the light distribution pattern by an LED array method in which a plurality of LEDs are arranged in an array, a scanning method using MEMS (Micro Electro Mechanical Systems), or the like. Note that the LED array method and the scanning method are well-known technologies, and therefore detailed explanations thereof will be omitted.

The headlights 4 include a left light (not shown) mounted on the left side of the vehicle 100 in the direction of travel of the vehicle 100, and a right light (not shown) mounted on the right side of the vehicle 100 in the direction of travel of the vehicle 100. The left light and right light each include a high beam unit (not shown) that illuminates distant areas and a low beam unit that illuminates nearby areas.

In the first embodiment, the area in front of the vehicle 100 where the high beam unit can irradiate a high beam is called the "high beam irradiable area." How far in front of the vehicle 100 the high beam irradiable area is, and how large the area is, is determined in advance according to the specifications of the high beam unit, etc. In the first embodiment, the area in front of the vehicle 100 where the low beam unit can irradiate a low beam is called the "low beam irradiable area." How far in front of the vehicle 100 the low beam irradiable area is, and how large the area is, is determined in advance according to the specifications of the low beam unit, etc.

The light distribution control device 1 according to the first embodiment performs control to emit or block high beams by, for example, turning on or off light sources (not shown) such as a plurality of LED light sources that constitute the headlight 4. In this way, the light distribution control device 1 controls the illumination range of light from the headlight 4.
The light distribution control device 1 is capable of not only turning on and off each light source, but also controlling the amount of light when it is turned on.

An example of the configuration of the light distribution control device 1 will be described.
The light distribution control device 1 includes an irradiation target presence/absence determination unit 11 , a brightness detection unit 12 , an irradiation necessity determination unit 13 , an irradiation condition determination unit 14 , and a light distribution control unit 15 .

The irradiation target presence/absence determination unit 11 acquires object information from the radio wave sensor, and determines, based on the acquired object information, the presence or absence of an irradiation target present in front of the vehicle 100. In detail, here, the irradiation target presence/absence determination unit 11 determines, based on the object information, the presence or absence of a person present in front of the vehicle 100.
As described above, the object information includes information on the presence of an object, the distance to the object, the shape of the object, etc. For example, when an object having a shape resembling an irradiation target is present ahead of the vehicle 100, the irradiation target presence/absence determination unit 11 determines that an irradiation target is present ahead of the vehicle 100.

When the irradiation target presence/absence determination unit 11 determines that an irradiation target is present in front of the vehicle 100, it acquires distance X, which is the horizontal distance in the direction of travel of the vehicle 100, and distance Y, which is the horizontal distance in the vehicle width direction, between the position of the vehicle 100 and the position of the irradiation target.
In addition, the irradiation target presence/absence determination unit 11 acquires the coordinates of the left end point Pl and the coordinates of the right end point Pr of the irradiation target. In the first embodiment, the left end point Pl of the irradiation target is the left end point of the irradiation target as seen from the vehicle 100, and the right end point Pr of the irradiation target is the right end point of the irradiation target as seen from the vehicle 100. The irradiation target presence/absence determination unit 11 acquires the x and y coordinates of the coordinates (x, y, z) of the left end point Pl of the irradiation target. In addition, the irradiation target presence/absence determination unit 11 acquires the x and y coordinates of the coordinates (x, y, z) of the right end point Pr of the irradiation target.

2 is a diagram for explaining the distance X, the distance Y, the left end point Pl of the irradiation target, and the right end point Pr of the irradiation target acquired by the irradiation target presence/absence determination unit 11 in the first embodiment. Note that FIG. 2 is a bird's-eye view of the vehicle 100 and a part of the lane on which the vehicle 100 is traveling, viewed from above. In the figure, the upward direction is the traveling direction of the vehicle 100.
In the first embodiment, the position of the vehicle 100 is represented by, for example, the center between the installation positions of the right light and the left light. In Fig. 2, the position of the vehicle 100 is indicated by "C". Also, in Fig. 2, the illumination target is indicated by "D".
In the first embodiment, the real space is represented by three-dimensional coordinate axes, for example, with the position of the vehicle 100 as the origin, the x-axis being an axis parallel to the vehicle length direction of the vehicle 100, in other words, the traveling direction of the vehicle 100, the y-axis being an axis parallel to the vehicle width direction of the vehicle 100, and the z-axis being an axis parallel to the vehicle height direction of the vehicle 100. Note that in the first embodiment, "parallel" is not limited to being strictly parallel, and includes approximately parallel.

2, distance X is the horizontal distance in the traveling direction of vehicle 100 from the reference point, which is the position of vehicle 100, to the position of the irradiation target. Distance Y is the horizontal distance in the vehicle width direction from the reference point, which is the position of vehicle 100, to the position of the irradiation target.
The information on the distance of the object included in the object information is, for example, information indicating the relative position between the installation position of the radio wave sensor and the position of the object. The position of the object is the position of the center of the object. Since the positional relationship between the installation position of the radio wave sensor and the installation positions of the right light and the left light is known in advance, the irradiation target presence/absence determination unit 11 can calculate the coordinate of the irradiation target in the traveling direction (x coordinate) of the vehicle 100 and the coordinate in the vehicle width direction (y coordinate) if the relative position between the installation position of the radio wave sensor and the object is known. In other words, the irradiation target presence/absence determination unit 11 can calculate the distance X and the distance Y.

Further, the irradiation target presence/absence determination unit 11 determines the width of the irradiation target to be a predetermined distance (e.g., 1.0 m) in the y-axis direction centered on the position of the irradiation target. More specifically, the width of the irradiation target is the width of the irradiation target in the left-right direction as viewed from the vehicle 100. In Fig. 2, the width of the irradiation target is indicated by "W". In Fig. 2, the position of the irradiation target is indicated by "P".
The irradiation target presence/absence determination unit 11 determines the left end point of the line segment on the ground indicating the width of the irradiation target as seen from the vehicle 100 as the left end point Pl of the irradiation target, and the right end point of the line segment as seen from the vehicle 100 as the right end point Pr of the irradiation target. Since the coordinates of the position of the irradiation target are known from the object information, the irradiation target presence/absence determination unit 11 can obtain the coordinates of the left end point Pl and the coordinates of the right end point Pr of the irradiation target from the position of the irradiation target and the width of the irradiation target.

The irradiation target presence/absence determination unit 11 generates information indicating whether or not an irradiation target is present ahead of the vehicle 100, and if an irradiation target is present, information including the acquired distance X, distance Y, coordinates of the left end point Pl, and coordinates of the right end point Pr of the irradiation target (hereinafter referred to as "irradiation target information"), and outputs the irradiation target information to the brightness detection unit 12.

The brightness detection unit 12 detects the brightness ahead of the vehicle 100 based on the irradiation target information output from the irradiation target presence/absence determination unit 11 and the vehicle front image output from the visible light camera.
More specifically, the brightness detection unit 12 detects the brightness of a target area in front of the vehicle 100 based on the illumination target information and the vehicle front image.
In addition, when the irradiation target presence/absence determination unit 11 determines that an irradiation target exists in front of the vehicle 100 based on the irradiation target information, the brightness detection unit 12 detects the brightness of the target area in front of the vehicle 100.

In the first embodiment, the brightness ahead of the vehicle 100 is represented by the gradation number data of the image ahead of the vehicle. That is, the brightness detection unit 12 detects the gradation number data of an area in the image ahead of the vehicle where the target area is captured (hereinafter referred to as the "target captured area").
In the first embodiment, the target area is represented by a rectangle on a plane parallel to the yz plane, with the line segment connecting the left end point Pl and the right end point Pr of the irradiation target as the base and a predetermined distance (for example, 1.6 m) as the height. Note that the line segment connecting the left end point Pl and the right end point Pr of the irradiation target is the width of the irradiation target, and as described above, the width of the irradiation target area is also predetermined here.

FIG. 3 is a diagram for explaining an example of a method in which the brightness detection unit 12 detects the brightness ahead of the vehicle 100 in the first embodiment.
In FIG. 3, the image ahead of the vehicle is indicated by "I", and the illumination target on the image ahead of the vehicle is indicated by "D'".
In embodiment 1, the image in front of the vehicle is represented by two-dimensional coordinate axes, for example, with the top left point of the image (indicated as "O" in Figure 3) as the origin, the left-right direction of the image as the u-axis, and the up-down direction of the image as the v-axis.

The brightness detection unit 12 first detects a target imaging area in an image of the area ahead of the vehicle.
Specifically, the brightness detection unit 12 converts the left end point Pl and the right end point Pr of the target area into points on the vehicle front image. In FIG. 3, the point obtained by converting the left end point Pl of the target area into a point on the vehicle front image (hereinafter referred to as the "lower left end point of the image") is indicated by "a". In addition, in FIG. 3, the point obtained by converting the right end point Pr of the target area into a point on the vehicle front image (hereinafter referred to as the "lower right end point of the image") is indicated by "b". The brightness detection unit 12 may perform the above-mentioned conversion using a known technique for converting the coordinates of a point in real space (so-called world coordinates) into coordinates on an image (so-called image coordinates). The lower left end point and the lower right end point of the image are the lower left end point and the lower right end point of the target imaging area, respectively.

When the brightness detection unit 12 acquires the lower left corner point and the lower right corner point of the image, the brightness detection unit 12 acquires the upper left corner point (hereinafter referred to as the "upper left corner point of the image") and the upper right corner point (hereinafter referred to as the "upper right corner point of the image") of the target imaging area from the coordinates of the acquired lower left corner point and the lower right corner point of the image and the height of the target area. Since the distance in the real space is known in advance on the vehicle front image, the brightness detection unit 12 can acquire the coordinates of the upper left corner point and the upper right corner point of the image based on the coordinates of the lower left corner point and the lower right corner point of the image and the height of the target area. In FIG. 3, the upper left corner point of the image is indicated by "d" and the upper right corner point of the image is indicated by "c".
In this manner, the brightness detection unit 12 detects the target imaging area, which is a rectangular area having the lower left corner point, the lower right corner point, the upper left corner point, and the upper right corner point of the image as its four corner points.
In FIG. 3, the target imaging area is indicated by "I'", the width of the irradiation target on the image ahead of the vehicle is indicated by "W'", and the height of the irradiation target on the image ahead of the vehicle is indicated by "H'".

Then, the brightness detection unit 12 detects the gradation number data of the detected target imaging area as the brightness of the target area. In the first embodiment, the gradation number data of the target imaging area is specifically the grayscale value corresponding to each pixel of the target imaging area. The brightness detection unit 12 may obtain the grayscale value corresponding to each pixel of the target imaging area using a known technique for obtaining the grayscale value of each pixel of an image.

The brightness detection unit 12 outputs to the irradiation necessity determination unit 13 information indicating the gradation number data of the detected target imaging area, in other words, the grayscale value corresponding to each pixel of the target imaging area (hereinafter referred to as "brightness information"), and the irradiation target information output from the irradiation target presence/absence determination unit 11.

The illumination necessity determination unit 13 determines whether or not it is necessary to illuminate the target area with light, based on the brightness ahead of the vehicle 100 detected by the brightness detection unit 12. More specifically, the illumination necessity determination unit 13 determines whether or not it is necessary to illuminate the target area with light, based on the brightness of the target area ahead of the vehicle 100 detected by the brightness detection unit 12.
The irradiation necessity determination unit 13 determines whether or not it is necessary to irradiate the target area with light when the irradiation target presence determination unit 11 determines, based on the object information, that an irradiation target exists ahead of the vehicle 100. The irradiation necessity determination unit 13 can specify, based on the irradiation target information, whether or not the irradiation target presence determination unit 11 has determined that an irradiation target exists ahead of the vehicle 100.

For example, if the irradiation necessity determination unit 13 determines that the target area is not bright, it determines that it is necessary to irradiate the target area with light, and if it determines that the target area is bright, it determines that it is not necessary to irradiate the target area with light.
The irradiation necessity determination unit 13 determines whether the target area is bright or not based on a preset condition (hereinafter referred to as a "brightness determination condition"). For example, the brightness determination condition is set to "if the average value of the grayscale values corresponding to each pixel of the target imaging area is equal to or greater than a preset threshold value (hereinafter referred to as a "brightness determination threshold value"), the target area is determined to be bright."
In this case, the irradiation necessity determining unit 13 determines whether the target area is bright or not by, for example, comparing the average value of the grayscale values corresponding to each pixel in the target imaging area with a brightness determination threshold value.
When the average value of the grayscale values corresponding to each pixel in the target imaging area is equal to or greater than the brightness determination threshold, the irradiation necessity determination unit 13 determines that the target area is bright and that it is not necessary to irradiate the target area with light. On the other hand, when the average value of the grayscale values corresponding to each pixel in the target imaging area is less than the brightness determination threshold, the irradiation necessity determination unit 13 determines that the target area is not bright, in other words, dark, and that it is necessary to irradiate the target area with light.

This is merely an example, and the irradiation necessity determination unit 13 may determine whether the target area is bright or not by other methods. That is, the brightness determination condition may be set with a condition other than the above-mentioned example. For example, the brightness determination condition may be set with a condition that "if the ratio of pixels whose grayscale values corresponding to each pixel in the target imaging area are less than the brightness determination threshold is less than a preset threshold (hereinafter referred to as the "ratio determination threshold"), the target area is determined to be bright."
In this case, the irradiation necessity determination unit 13 determines whether the target area is bright or not by using the ratio of pixels whose corresponding grayscale values are less than the brightness determination threshold among the pixels in the target imaging area. That is, the irradiation necessity determination unit 13 determines whether the target area is bright or not by comparing the ratio of pixels whose grayscale values corresponding to each pixel in the target imaging area are less than the brightness determination threshold with the ratio determination threshold. The irradiation necessity determination unit 13 determines that the target area is bright if the ratio of pixels whose grayscale values corresponding to each pixel in the target imaging area are less than the brightness determination threshold is less than the ratio determination threshold, and determines that the target area is not bright if the ratio of pixels whose grayscale values corresponding to each pixel in the target imaging area are less than the brightness determination threshold is equal to or greater than the ratio determination threshold.
The brightness determination conditions described above are merely examples. Conditions for the brightness determination conditions to be used by the irradiation necessity determination unit 13 to determine whether the target area is bright or not can be appropriately set as the brightness determination conditions.

The irradiation necessity determining unit 13 outputs the determination result as to whether or not it is necessary to irradiate the target area with light (hereinafter referred to as the “irradiation necessity determination result”) to the irradiation condition determining unit 14 together with the irradiation target information.
At this time, if the illumination necessity determination unit 13 determines that it is necessary to irradiate the target area with light, it sets the illumination necessity flag to "1", and if it determines that it is not necessary to irradiate the target area with light, it sets the illumination necessity flag to "0". The illumination necessity flag is set in a location that can be referenced by the light distribution control device 1. The initial value of the illumination necessity flag is "0". The illumination necessity flag is initialized, for example, when the power of the vehicle 100 is turned off or the automatic high beam control is turned on.

The illumination condition determining unit 14 determines illumination conditions for the headlights 4 based on the illumination necessity determination result output from the illumination necessity determining unit 13 .
In detail, when the irradiation necessity determination unit 13 determines that it is necessary to irradiate the target area with light, the irradiation condition determination unit 14 determines irradiation conditions for brightening the target area for the headlights 4. When the irradiation necessity determination unit 13 determines that it is not necessary to irradiate the target area with light, the irradiation condition determination unit 14 determines irradiation conditions for setting the light irradiation state of the headlights 4 to an initial state. In the first embodiment, the initial state of the light irradiation state refers to a state in which high beam irradiation is not required and the irradiation range of the low beam is set to the range of the low beam irradiable area.
For example, the illumination condition determination unit 14 determines the illumination range of the light from the headlights 4 as the illumination condition.

For example, when the illumination necessity determination unit 13 determines that it is necessary to illuminate the target area with light, the illumination condition determination unit 14 controls the illumination range of the light of the headlight 4 by setting the illumination range of the high beam to the range of the target area within the high beam irradiable area so as to brighten the target area. In other words, when the illumination necessity determination unit 13 determines that it is necessary to illuminate the target area with light, the illumination condition determination unit 14 determines the illumination range of the high beam to be the range of the target area within the high beam irradiable area as the illumination condition for the headlight 4.
When the illumination necessity determination unit 13 determines that it is not necessary to irradiate the target area with light, the illumination condition determination unit 14 determines that high beam illumination is not necessary. In other words, the range of the area where low beam illumination is possible becomes the illumination range of the light from the headlight 4.

In embodiment 1, the range of the target area within the high beam illumination area is expressed in terms of an angle relative to a straight line (hereinafter referred to as the “reference line”) that passes through the position of vehicle 100 and extends in the direction of vehicle 100's travel as the reference (0°).
For example, the illumination condition determination unit 14 determines the range of the target area to be the range from the angle between the reference line and a line passing through the position of the vehicle 100 and the left end point Pl of the illumination target (hereinafter referred to as the "left side line") to the angle between the reference line and a line passing through the position of the vehicle 100 and the right end point Pr of the illumination target (hereinafter referred to as the "right side line").

FIG. 4 is a diagram for explaining an example of the range of the target region determined as the irradiation condition by the irradiation condition determination unit 14 in the first embodiment.
In FIG. 4, the reference line is indicated by "RL", the left line is indicated by "L1", and the right line is indicated by "L2".
The irradiation condition determination unit 14 determines the range of the target area to be the angle between the reference line and the left line (shown as "θl" in FIG. 4) and the angle between the reference line and the right line (shown as "θr" in FIG. 4), i.e., the range of the angle shown as "θs" in FIG. 4.
Furthermore, based on the coordinates of the left endpoint Pl of the target area and the coordinates of the right endpoint Pr of the target area, the irradiation condition determination unit 14 can calculate the angle between the reference line and the left line and the angle between the reference line and the right line.

For example, the irradiation condition determination unit 14 may determine the target region as a region having a margin with respect to the width or height of the irradiation target.
As a specific example, the illumination condition determination unit 14 corrects the coordinates of the left end point Pl of the target area to the coordinates of a position horizontally moved to the left as viewed from the vehicle 100 so that the distance from the position of the irradiation target (indicated by "P" in FIG. 4) becomes 1.1 times, and corrects the coordinates of the right end point Pr of the target area to the coordinates of a position horizontally moved to the right as viewed from the vehicle 100 so that the distance from the position of the irradiation target becomes 1.1 times. Then, the illumination condition determination unit 14 sets the target area based on the left end point Pl and the right end point Pr of the corrected target area. This allows the illumination condition determination unit 14 to set the illumination range of the light of the headlight 4, more specifically, the high beam, for illuminating the target area with light to a range with a margin provided with respect to the width of the irradiation target.

The illumination condition determination unit 14 outputs the determined illumination conditions to the light distribution control unit 15.

The light distribution control unit 15 controls the headlights 4 according to the illumination conditions determined by the illumination condition determination unit 14.

The operation of the light distribution control device 1 according to the first embodiment will be described.
FIG. 5 is a flowchart for explaining the operation of the light distribution control device 1 according to the first embodiment.
For example, when the light distribution control device 1 receives an instruction to start light distribution control, it starts the operation shown in the flowchart of Figure 5, and repeats the operation shown in the flowchart of Figure 5 until it receives an instruction to end light distribution control or until the power to the vehicle 100 is turned off.

The irradiation target presence/absence determining unit 11 acquires object information from the radio wave sensor, and determines the presence or absence of an irradiation target present in front of the vehicle 100 based on the acquired object information (step ST1).
The irradiation object presence/absence determining unit 11 generates irradiation object information, and outputs the irradiation object information to the brightness detecting unit 12 .

The brightness detection unit 12 determines, based on the irradiation target information, whether or not the irradiation target presence determination unit 11 has determined that an irradiation target exists in front of the vehicle 100 (step ST11).
In step ST11, when the irradiation target presence/absence determination unit 11 determines that an irradiation target exists in front of the vehicle 100 (in the case of "YES" in step ST11), the brightness detection unit 12 detects the brightness in front of the vehicle 100 based on the irradiation target information output from the irradiation target presence/absence determination unit 11 in step ST1 and the vehicle front image output from the visible light camera. More specifically, the brightness detection unit 12 detects the brightness of the target area in front of the vehicle 100 based on the irradiation target information and the vehicle front image (step ST2).
The brightness detection unit 12 outputs the brightness information and the irradiation object information output from the irradiation object presence/absence determination unit 11 in step ST1 to the irradiation necessity determination unit 13.

On the other hand, if the brightness detection unit 12 determines in step ST11 that the illumination target presence/absence determination unit 11 has determined that there is no illumination target in front of the vehicle 100 (if "NO" in step ST11), the light distribution control device 1 ends the operation shown in the flowchart of FIG. 5.

The illumination necessity determining unit 13 determines whether or not it is necessary to illuminate the target area with light, based on the brightness ahead of the vehicle 100 detected by the brightness detecting unit 12 in step ST2.
More specifically, the illumination necessity determination unit 13 determines whether or not it is necessary to illuminate the target area with light, based on the brightness of the target area in front of the vehicle 100 detected by the brightness detection unit 12 in step ST2 (step ST3).
The irradiation necessity determining unit 13 outputs the irradiation necessity determination result together with the irradiation target information to the irradiation condition determining unit 14 .
At this time, if the irradiation necessity determination unit 13 determines that it is necessary to irradiate the target area with light, it sets the irradiation necessity flag to "1", and if it determines that it is not necessary to irradiate the target area with light, it sets the irradiation necessity flag to "0".

The illumination condition determining unit 14 determines illumination conditions for the headlights 4 based on the illumination necessity determination result output from the illumination necessity determining unit 13 in step ST3 (step ST4).
The irradiation condition determination unit 14 outputs the determined irradiation conditions to the light distribution control unit 15 .

The light distribution control unit 15 controls the headlights 4 according to the illumination conditions determined by the illumination condition determination unit 14 in step ST4 (step ST5).

FIG. 6 is a flowchart for explaining the details of step ST2 in FIG. 5.

The brightness detection unit 12 detects a target imaging area in the image ahead of the vehicle based on the illumination target information and the image ahead of the vehicle (step ST21).
The brightness detection unit 12 detects the grayscale data of the target imaging area detected in step ST21, in other words, the grayscale value corresponding to each pixel of the target imaging area, as the brightness of the target area (step ST22).
The brightness detection unit 12 outputs the brightness information and the irradiation object information to the irradiation necessity determination unit 13 (step ST23).

FIG. 7 is a flowchart for explaining the details of step ST3 in FIG. 5.

The irradiation necessity determination unit 13 determines whether the target area is bright or not based on the brightness information (step ST31).

If it is determined in step ST31 that the target area is not bright ("NO" in step ST31), the irradiation necessity determination unit 13 determines that it is necessary to irradiate the target area with light (step ST33). The irradiation necessity determination unit 13 sets the irradiation necessity flag to "1" and outputs the irradiation necessity determination result together with the irradiation target information to the irradiation condition determination unit 14.

If it is determined in step ST31 that the target area is bright ("YES" in step ST31), the irradiation necessity determination unit 13 determines that it is not necessary to irradiate the target area with light (step ST32). The irradiation necessity determination unit 13 sets the irradiation necessity flag to "0" and outputs the irradiation necessity determination result together with the irradiation target information to the irradiation condition determination unit 14.

FIG. 8 is a flow chart for explaining the details of step ST4 in FIG.
The irradiation condition determining unit 14 determines, based on the irradiation necessity determination result, whether or not the irradiation necessity determining unit 13 has determined that it is necessary to irradiate the target region with light (step ST41).

If the illumination necessity determination unit 13 determines in step ST41 that illumination of the target area is necessary (if "YES" in step ST41), the illumination condition determination unit 14 determines illumination conditions to brighten the target area (step ST42). Then, the illumination condition determination unit 14 outputs the determined illumination conditions to the light distribution control unit 15.

If the irradiation necessity determination unit 13 determines in step ST41 that it is not necessary to irradiate the target area with light (if "NO" in step ST41), the irradiation condition determination unit 14 determines the irradiation conditions so that the irradiation state is set to the initial state (step ST43). Then, the irradiation condition determination unit 14 outputs the determined irradiation conditions to the light distribution control unit 15.

In this way, the light distribution control device 1 determines whether or not there is an illumination target present in front of the vehicle 100 based on object information (first outside information) related to objects present around the vehicle 100.
In addition, the light distribution control device 1 detects the brightness of a target area ahead of the vehicle 100 based on the illumination target information and a vehicle front image (second outside information) for determining the brightness ahead of the vehicle 100.
When the light distribution control device 1 determines that an illumination target exists in front of the vehicle 100, it determines whether or not it is necessary to illuminate the target area with light, based on the brightness of the target area.
Then, the light distribution control device 1 determines the light irradiation conditions for the headlights 4 based on the result of the determination as to whether or not it is necessary to irradiate the target area with light, and controls the headlights 4 in accordance with the determined irradiation conditions.
Therefore, the light distribution control device 1 can perform light distribution control taking into account the brightness around the target to be illuminated.

The above-mentioned conventional technology does not take into consideration the brightness of the location where the illumination target exists, in other words, the brightness of the target area. Therefore, the conventional technology irradiates the illumination target with light even in cases where it is considered unnecessary to irradiate the illumination target with light, such as when a streetlight is shining on the illumination target and the driver is expected to be able to see the illumination target without irradiating the illumination target with light.
In response to this, the light distribution control device 1 determines the light irradiation conditions for the headlights 4 in consideration of the brightness of the target area, as described above. For example, when the target area is not bright, the light distribution control device 1 determines the light irradiation conditions for the headlights 4 so that the target area is brightened and high beams are irradiated onto the target area. Conversely, for example, when the target area is bright, the light distribution control device 1 determines the light irradiation conditions for the headlights 4 so that high beams are not irradiated onto the target area. By determining the irradiation conditions based on the brightness of the target area, the light distribution control device 1 can irradiate the irradiation target with light only in a situation where it is assumed that the occupants of the vehicle 100 or the outside brightness detection device 3 (visible light camera) have difficulty finding the irradiation target. In other words, the light distribution control device 1 can avoid unnecessary irradiation of the light of the headlights 4 onto the target area, improve the visibility of the irradiation target, and suppress glare to other traffic participants (for example, oncoming vehicles, etc.).

In the first embodiment described above, the brightness detection unit 12 detects the brightness of a target area in front of the vehicle 100, based on the illumination target information and the vehicle front image, by focusing on the target area.
Specifically, the brightness detection unit 12 detects a target imaging area in the vehicle front image based on the irradiation target information output from the irradiation target presence/absence determination unit 11 and the vehicle front image output from the visible light camera, and detects the brightness of the target area from the gradation number data of the target imaging area, in other words, the grayscale value corresponding to each pixel of the target imaging area. Then, the irradiation necessity determination unit 13 determines whether or not it is necessary to irradiate the target area with light based on the brightness of the target area detected by the brightness detection unit 12. However, this is merely one example.

For example, the brightness detection unit 12 may detect the brightness ahead of the vehicle 100 without narrowing down the target area. Specifically, the brightness detection unit 12 may detect the gradation number data of all areas on the image ahead of the vehicle, in other words, the grayscale value corresponding to each pixel of the image ahead of the vehicle, and detect this as the brightness ahead of the vehicle 100.
In this case, the illumination necessity determination unit 13 detects a target imaging area in which the target area is imaged in the image ahead of the vehicle, and determines whether or not it is necessary to irradiate the target area with light based on the gradation number data of the detected target imaging area. In this case, the illumination target presence/absence determination unit 11 outputs illumination target information to the illumination necessity determination unit 13, not to the brightness detection unit 12.
The brightness detection unit 12 detects the brightness ahead of the vehicle 100 based on the vehicle front image.
The illumination necessity determining unit 13 detects a target imaging area based on the illumination target information, the vehicle forward image, and brightness information, determines the brightness of the target area, and determines whether or not it is necessary to irradiate the target area with light from the headlights 4.

In this case, the brightness detection unit 12 may detect the brightness ahead of the vehicle 100 without narrowing down the target region in step ST2 in the operation of the light distribution control device 1 described using the flowchart of Fig. 5. The brightness detection unit 12 may omit the processing of step ST21 in the operation of the light distribution control device 1 described using the flowchart of Fig. 6, and detects the grayscale values corresponding to each pixel in all regions of the image ahead of the vehicle as the brightness ahead of the vehicle 100 in step ST22.
In the operation of the light distribution control device 1 described using the flowchart of Figure 7, before processing step ST31, the illumination necessity determination unit 13 detects a target imaging area based on the illumination target information and the image in front of the vehicle, and identifies a grayscale value corresponding to each pixel of the detected target imaging area based on the brightness information.

However, if the brightness detection unit 12 detects the brightness of a target area based on the illumination target information and the image ahead of the vehicle, the range in which the brightness is detected (i.e., the grayscale value is detected) can be narrowed, thereby reducing the processing load on the light distribution control device 1.

In the above first embodiment, the brightness determination threshold value is fixedly determined, but this is merely an example.
The illumination necessity determination unit 13 can also adjust the brightness determination threshold based on, for example, the position of the vehicle 100 or the illumination target and map information. The illumination necessity determination unit 13 may obtain information on the position of the vehicle 100 from a vehicle position acquisition device mounted on the vehicle 100. The illumination necessity determination unit 13 may obtain map information from a map database connected to the light distribution control device 1 via a network. The map information includes information on road types.

For example, the illumination necessity determination unit 13 can change the brightness determination threshold value depending on the position of the vehicle 100 and the road type. For example, if an intersection in the traveling direction of the vehicle 100 is located near the vehicle 100, there is a high possibility that the illumination target will cross the intersection. Therefore, when an intersection is located near the vehicle 100 in the traveling direction of the vehicle 100, the illumination necessity determination unit 13 increases the brightness determination threshold value compared to when the intersection is located far from the vehicle 100. This makes it easier for the illumination necessity determination unit 13 to determine that the target area is not bright. As a result, when it is assumed that the occupants of the vehicle 100 need to pay more attention to the target area, the light distribution control device 1 can make the target area brighter, making it easier for the occupants of the vehicle 100 to find the illumination target.

Also, for example, the illumination necessity determination unit 13 acquires a traffic accident occurrence map as map information, and based on the position of the vehicle 100 and the map information, if the vehicle 100 is in a place where nighttime accidents are likely to occur, the brightness determination threshold is increased. As a result, the light distribution control device 1 makes it easier for the headlights 4 to illuminate the target area even if it is relatively bright in a place where nighttime accidents are likely to occur, thereby reducing the possibility of the vehicle 100 getting into an unexpected situation.

Also, for example, when the vehicle 100 is traveling in a relatively bright place such as an urban area, the illumination necessity determination unit 13 lowers the brightness determination threshold so that the target area is more likely to be determined to be bright.Also, for example, when the vehicle 100 is traveling in a place with poor visibility, the illumination necessity determination unit 13 raises the brightness determination threshold so that the target area is less likely to be determined to be bright.In addition, information about places such as urban areas and information about places with poor visibility is included in the map information.

Furthermore, for example, the irradiation necessity determining unit 13 may obtain a setting value of the visible light camera from the visible light camera, and change the brightness determination threshold value based on the setting value of the visible light camera.
For example, the illumination necessity determination unit 13 sets the brightness determination threshold to be larger when the exposure of the visible light camera is high than when the exposure is low. This allows the light distribution control device 1 to determine the brightness of the target area using an appropriate brightness determination threshold even if the setting value of the visible light camera changes depending on the surrounding brightness. This allows the light distribution control device 1 to determine the brightness of the target area according to the environment of the target area, thereby improving the accuracy of the determination of the brightness of the target area.

In the above-described first embodiment, the light distribution control of the headlight 4 performed by the light distribution control device 1 is specifically assumed to be control of the irradiation range of the light emitted by the headlight 4, and the irradiation condition determination unit 14 determines the irradiation range of the light of the headlight 4 as the irradiation condition. However, this is merely one example.
For example, the illumination condition determination unit 14 may determine, as the illumination conditions, the illumination range and the illumination amount of the light of the headlight 4. Even in this manner, the light distribution control device 1 can perform light distribution control taking into account the brightness around the illumination target.

Furthermore, the illumination condition determination unit 14 may change the amount of light that the headlight 4 emits, more specifically, the high beam, depending on the brightness of the target area. For example, the illumination condition determination unit 14 determines the illumination conditions so that the amount of light emitted in the high beam illumination range increases the smaller the brightness of the target area, in other words, the smaller the average value of the grayscale values corresponding to each pixel in the target imaging area is below the brightness determination threshold.

As a result, when the light distribution control device 1 irradiates a target area with light from the headlights 4, it is possible to irradiate the target area with a sufficient amount of light for the occupants of the vehicle 100 to see the illuminated target, according to the brightness of the target area, and to prevent unnecessary glare from being caused to traffic participants around the illuminated target.

In addition, in the above-described first embodiment, if the irradiation necessity determination unit 13 determines that it is not necessary to irradiate the target area with light, the light distribution control unit 15 may cause the headlight 4 to reset the state of irradiating the target area with light to the initial state after a preset time has elapsed. In detail, for example, after controlling the headlight 4 according to the irradiation conditions determined by the irradiation condition determination unit 14 based on the irradiation necessity determination result in which the irradiation necessity determination unit 13 determines that it is necessary to irradiate the target area with light, if the irradiation necessity determination unit 13 determines that it is not necessary to irradiate the target area with light, the light distribution control unit 15 may cause the headlight 4 to reset the state of irradiating the target area with light to the initial state after a preset time (hereinafter referred to as the "first determination time") has elapsed.

In this case, for example, when the irradiation necessity determination unit 13 sets the irradiation necessity flag to "0" because it has determined that it is not necessary to irradiate the target area with light (see step ST3 in FIG. 5), if the irradiation necessity flag before setting it to "0" was "1" (in other words, if the value of the irradiation necessity flag has been rewritten from "1" to "0"), the irradiation necessity determination unit 13 outputs information indicating that the rewriting has been performed (hereinafter referred to as "flag rewrite information") to the light distribution control unit 15 via the irradiation condition determination unit 14.

When the flag rewrite information is output, the light distribution control unit 15 controls the headlights 4 according to the illumination conditions determined by the illumination condition determination unit 14 based on the illumination necessity determination result in which the illumination necessity determination unit 13 has determined that illumination of the target area with light is necessary, and then determines that the illumination necessity determination unit 13 has determined that illumination of the target area with light is unnecessary. Then, the light distribution control unit 15 starts counting the elapsed time. After the first determination time has elapsed, the light distribution control unit 15 resets the state of illumination of the target area to the initial state. Note that, if the illumination necessity determination unit 13 has determined that illumination of the target area with light is unnecessary, the illumination condition determination unit 14 determines the illumination conditions so that the illumination state of the headlights 4 is reset to the initial state. After the first determination time has elapsed, the light distribution control unit 15 controls the headlights 4 according to the illumination conditions determined by the illumination condition determination unit 14. The light distribution control unit 15 controls the light distribution of the headlight 4 so that light is irradiated to the target area regardless of the irradiation conditions from the irradiation condition determination unit 14, in other words, regardless of the result of the irradiation necessity determination, until the first determination time has elapsed.

As a result, the light distribution control device 1 can reduce the possibility of causing annoyance to the occupants of the vehicle 100 due to sudden or frequent changes in whether or not the headlights 4 are irradiating the target area.

In addition, in the above-described first embodiment, when the irradiation necessity determination unit 13 determines that irradiation of the target area with light is not necessary, the light distribution control unit 15 may cause the headlight 4 to reset the state of irradiation of the target area with light to the initial state after a preset time has elapsed by another method. In detail, for example, the light distribution control unit 15 may cause the headlight 4 to reset the state of irradiation of the target area with light to the initial state after the irradiation necessity determination unit 13 determines that irradiation of the target area with light is not necessary by controlling the headlight 4 according to the irradiation conditions determined by the irradiation condition determination unit 14 based on the irradiation necessity determination result in which the irradiation necessity determination unit 13 determines that irradiation of the target area with light is necessary, and then cause the headlight 4 to reset the state of irradiation of the target area with light to the initial state after the state in which the irradiation necessity determination unit 13 determines that irradiation of the target area with light is not necessary continues for a preset time (hereinafter referred to as the "second determination time").

In this case, for example, when the irradiation necessity determination unit 13 determines that the irradiation of the target area is unnecessary (see step ST3 in FIG. 5), it determines whether the irradiation necessity flag is currently "1" or "0". When the irradiation necessity flag is "1", the irradiation necessity determination unit 13 starts counting the time. After starting the counting of the time, the irradiation necessity determination unit 13 continues counting the time while it determines that the irradiation of the target area is unnecessary, and clears the time count when it determines that the irradiation of the target area is necessary. Then, when the counting time reaches the second determination time, the irradiation necessity determination unit 13 sets the irradiation necessity flag to "0" and outputs the irradiation necessity determination result indicating that the irradiation of the target area is unnecessary to the irradiation condition determination unit 14.
In addition, when it is determined that it is not necessary to irradiate the target area with light and the current irradiation necessity flag is "1", the irradiation necessity determination unit 13 outputs the irradiation necessity determination result indicating that it is necessary to irradiate the target area with light to the irradiation condition determination unit 14 until the counting time reaches the second determination time, and does not rewrite the irradiation necessity flag to "0".

As a result, after the light distribution control unit 15 controls the headlights 4 in accordance with the illumination conditions determined by the illumination condition determination unit 14 based on the illumination necessity determination result in which the illumination necessity determination unit 13 has determined that illumination of the target area with light is necessary, illumination conditions that reset the state of illumination of the target area to the initial state are output from the illumination condition determination unit 14 to the light distribution control unit 15 after the state in which the illumination necessity determination unit 13 has determined that illumination of the target area with light is unnecessary continues for the second determination time. As a result, the light distribution control unit 15 resets the state of illumination of the target area with light to the initial state for the headlights 4 after the state in which the illumination necessity determination unit 13 has determined that illumination of the target area with light is unnecessary continues for the second determination time.

As a result, the light distribution control device 1 can reduce the possibility of causing annoyance to the occupants of the vehicle 100 due to sudden or frequent changes in whether or not the headlights 4 are irradiating the target area.

In addition, the first determination time and the second determination time may be the same length.

In addition, in the above embodiment 1, the irradiation target presence/absence determination unit 11 acquires the coordinates of the left end point Pl of the irradiation target and the coordinates of the right end point Pr of the irradiation target based on the width of the irradiation target, which is a predetermined distance, but this is merely one example.
For example, the radio wave sensor may be able to detect the end points of an object. In this case, the object information includes information on the left and right end points of the object. The irradiation object presence/absence determination unit 11 may obtain the coordinates of the left end point Pl and the right end point Pr of the irradiation object from the object information.
The object information may include information on the bottom and top ends of the object. In this case, the brightness detection unit 12 can obtain the height of the irradiation target based on the object information without using the height of the irradiation target, which is a predetermined distance. The brightness detection unit 12 may obtain the object information via the irradiation target presence/absence determination unit 11, for example.

In the above embodiment 1, the headlight 4 is assumed to be a variable light distribution type headlight, but this is merely an example. In the above embodiment 1, the headlight 4 may be, for example, a spotlight type headlight that has a spotlight in addition to a high beam and a low beam.
In this case, the light distribution control device 1 performs control to emit spotlights.

In the above-described first embodiment, the illumination range is expressed by an angle in the horizontal direction as viewed from the vehicle 100, but this is merely an example.
The illumination range may be expressed in terms of horizontal and vertical angles as viewed from the vehicle 100 .

In addition, in the above-described first embodiment, the outside object detection device 2 is a radio wave sensor including a millimeter wave radar or an optical sensor including a LiDAR, but this is merely one example.
The external object detection device 2 may be, for example, a far-infrared camera, and may be any device capable of detecting objects present around the vehicle 100 even in a dark place.

In the above embodiment 1, the vehicle exterior brightness detection device 3 is a visible light camera, but this is merely one example.
The outside brightness detection device 3 may be, for example, a light meter, and may be any device capable of detecting at least the brightness ahead of the vehicle 100 .

In addition, in the above embodiment 1, the irradiation target presence/absence determination unit 11 determines that there is an irradiation target if an object that resembles an irradiation target is present in front of the vehicle 100, regardless of the position of the object detected in front of the vehicle 100, but this is merely one example.
For example, even if there is a person in front of the vehicle 100, if there is an oncoming lane between the person and the lane in which the vehicle 100 is traveling, and if the person is located at a certain distance or more away from the oncoming lane as viewed from the vehicle 100, it is expected that it will take some time for the person to become a visual target for the occupants of the vehicle 100. This is because, even if a person located at a certain distance or more away from the oncoming lane crosses the oncoming lane, it is estimated that the possibility of them crossing immediately is low.
For example, the same can be said when a person is present in front of the vehicle 100 but the person is present on the shoulder of the road on the left side of the lane in which the vehicle 100 is traveling (here, as an example, the vehicle 100 drives on the left side). In this case, too, if the person present on the shoulder is a certain distance away or further, it is expected that it will take some time for the person to become a visual target for the occupants of the vehicle 100.
Therefore, for example, the irradiation target presence/absence determining unit 11 may narrow down the range and determine the presence/absence of an irradiation target.
For example, the irradiation target presence/absence determination unit 11 may determine whether or not an irradiation target is present in front of the vehicle 100 within a predetermined distance range from the lane in which the vehicle 100 is traveling (including the oncoming lane).
The light distribution control device 1 narrows down the range and determines the presence or absence of an illumination target, so that it is possible to reduce the processing load related to controlling the illumination of light to a target area.

In addition, in the above embodiment 1, in the light distribution control device 1, for example, if the illumination necessity determination unit 13 determines that the target area is not bright, it determines that it is necessary to illuminate the target area with light, and if it determines that the target area is bright, it determines that it is not necessary to illuminate the target area with light.
However, this is merely one example, and for example, the irradiation necessity determining unit 13 may determine that it is necessary to irradiate the target area with light even when it determines that the target area is bright.
For example, when an illumination target is on the path of the vehicle 100 or is approaching the vehicle 100, the occupants of the vehicle 100 should be able to visually confirm the illumination target without fail so that the vehicle 100 or the occupants of the vehicle 100 do not fall into an unexpected situation. Therefore, when the illumination necessity determination unit 13 determines that the target area is bright, it may determine that it is necessary to illuminate the target area with light.
For example, the irradiation necessity determining unit 13 determines that it is necessary to irradiate the target area with light even if the average value of the grayscale values corresponding to each pixel in the target imaging area is equal to or greater than the brightness determination threshold value.
For example, the irradiation necessity determination unit 13 may determine that it is necessary to irradiate the target area with light even if the proportion of pixels whose grayscale values corresponding to each pixel in the target imaging area are less than the brightness determination threshold is less than the proportion determination threshold.

Furthermore, for example, even if it is determined that the target area is not bright, the irradiation necessity determining unit 13 may determine that it is not necessary to irradiate the target area with light.
For example, it can be said that there is a low possibility that the vehicle 100 or the occupants of the vehicle 100 will encounter an unexpected incident when the illumination target is located at a predetermined distance or more away from the path of the vehicle 100. Therefore, even when the illumination necessity determination unit 13 determines that the target area is not bright, it may determine that it is not necessary to illuminate the target area with light.
For example, even if the average value of the grayscale values corresponding to each pixel in the target imaging area is less than the brightness determination threshold, the irradiation necessity determining unit 13 determines that it is not necessary to irradiate the target area with light.
For example, the irradiation necessity determination unit 13 may determine that it is not necessary to irradiate the target area with light even if the proportion of pixels whose grayscale values corresponding to each pixel in the target imaging area are less than the brightness determination threshold is equal to or greater than the proportion determination threshold.

In the above embodiment 1, the light distribution control device 1 is an in-vehicle device mounted on the vehicle 100, and the irradiation target presence/absence determination unit 11, brightness detection unit 12, irradiation necessity determination unit 13, irradiation condition determination unit 14, and light distribution control unit 15 are provided in the in-vehicle device. However, some of the irradiation target presence/absence determination unit 11, brightness detection unit 12, irradiation necessity determination unit 13, irradiation condition determination unit 14, and light distribution control unit 15 may be provided in the in-vehicle device of the vehicle 100, and the rest may be provided in a server connected to the in-vehicle device via a network. Also, all of the irradiation target presence/absence determination unit 11, brightness detection unit 12, irradiation necessity determination unit 13, irradiation condition determination unit 14, and light distribution control unit 15 may be provided in the server.

9A and 9B are diagrams illustrating an example of a hardware configuration of the light distribution control device 1 according to the first embodiment.
In the first embodiment, the functions of the illumination target presence/absence determining unit 11, the brightness detecting unit 12, the illumination necessity determining unit 13, the illumination condition determining unit 14, and the light distribution control unit 15 are realized by a processing circuit 1001. That is, the light distribution control device 1 includes the processing circuit 1001 for performing light distribution control of the headlights 4 in consideration of the brightness of a target area, based on the first outside-vehicle information and the second outside-vehicle information.
The processing circuitry 1001 may be dedicated hardware as shown in FIG. 9A, or may be a processor 1004 executing a program stored in a memory 1005 as shown in FIG. 9B.

If the processing circuit 1001 is dedicated hardware, the processing circuit 1001 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these.

When the processing circuit is the processor 1004, the functions of the irradiation target presence/absence determination unit 11, brightness detection unit 12, irradiation necessity determination unit 13, irradiation condition determination unit 14, and light distribution control unit 15 are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 1005. The processor 1004 executes the functions of the irradiation target presence/absence determination unit 11, brightness detection unit 12, irradiation necessity determination unit 13, irradiation condition determination unit 14, and light distribution control unit 15 by reading and executing the program stored in the memory 1005. In other words, the light distribution control device 1 includes a memory 1005 for storing a program that, when executed by the processor 1004, results in the execution of steps ST1 to ST5 of FIG. 5 described above. In addition, the program stored in the memory 1005 can also be said to cause the computer to execute the processing procedures or methods of the irradiation target presence/absence determination unit 11, the brightness detection unit 12, the irradiation necessity determination unit 13, the irradiation condition determination unit 14, and the light distribution control unit 15. Here, memory 1005 includes, for example, non-volatile or volatile semiconductor memory such as RAM, ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disc), etc.

The functions of the irradiation target presence/absence determination unit 11, the brightness detection unit 12, the irradiation necessity determination unit 13, the irradiation condition determination unit 14, and the light distribution control unit 15 may be partially realized by dedicated hardware and partially realized by software or firmware. For example, the functions of the irradiation target presence/absence determination unit 11 and the brightness detection unit 12 can be realized by a processing circuit 1001 as dedicated hardware, and the functions of the irradiation necessity determination unit 13, the irradiation condition determination unit 14, and the light distribution control unit 15 can be realized by the processor 1004 reading and executing a program stored in the memory 1005.
The light distribution control device 1 also includes an input interface device 1002 and an output interface device 1003 that perform wired or wireless communication with devices such as an outside object detection device 2, an outside brightness detection device 3, or a headlight 4.

As described above, the light distribution control device 1 according to the first embodiment is configured to include an irradiation target presence/absence determination unit 11 which determines the presence or absence of an irradiation target present ahead of the vehicle 100 based on the first external information related to an object present ahead of the vehicle 100, a brightness detection unit 12 which detects the brightness ahead of the vehicle 100 based on the second external information for determining the brightness ahead of the vehicle 100, an illumination necessity determination unit 13 which, when the illumination target presence/absence determination unit 11 determines that an illumination target exists ahead of the vehicle 100, determines whether or not it is necessary to irradiate a target area in which the illumination target exists, based on the brightness ahead of the vehicle 100 detected by the brightness detection unit 12, an illumination condition determination unit 14 which determines the illumination conditions for the headlights 4 based on the determination result by the illumination necessity determination unit 13 as to whether or not it is necessary to irradiate the target area with light, and a light distribution control unit 15 which controls the headlights 4 in accordance with the illumination conditions determined by the illumination condition determination unit 14.
Therefore, the light distribution control device 1 can perform light distribution control taking into account the brightness around the target to be illuminated.

Note that this disclosure allows for modification of any of the components of the embodiments, or omission of any of the components of the embodiments.

The light distribution control device according to the present disclosure can perform light distribution control of headlights in a vehicle, taking into account the brightness of the area around the target to be illuminated.

1 Light distribution control device, 11 Irradiation target presence/absence determination unit, 12 Brightness detection unit, 13 Irradiation necessity determination unit, 14 Irradiation condition determination unit, 15 Light distribution control unit, 2 Vehicle exterior object detection device, 3 Vehicle exterior brightness detection device, 4 Headlight, 100 Vehicle, 10 Light distribution control system, 1001 Processing circuit, 1002 Input interface device, 1003 Output interface device, 1004 Processor, 1005 Memory.

Claims (14)

1. an illumination target presence/absence determination unit that determines the presence or absence of an illumination target present in front of the vehicle based on first outside information related to an object present around the vehicle;
   a brightness detection unit that detects brightness ahead of the vehicle based on second outside information for determining brightness ahead of the vehicle;
   an illumination necessity determination unit that, when the illumination target presence/absence determination unit determines that the illumination target exists ahead of the vehicle, determines whether or not it is necessary to illuminate a target area where the illumination target exists based on the brightness ahead of the vehicle detected by the brightness detection unit;
   an illumination condition determination unit that determines illumination conditions for the headlights based on a result of the determination by the illumination necessity determination unit as to whether or not it is necessary to irradiate the target area with the light;
   a light distribution control unit that controls the headlights in accordance with the illumination conditions determined by the illumination condition determination unit.
2. The light distribution control device according to claim 1 , wherein the second outside information is an image captured by a visible light camera of an area ahead of the vehicle.
3. The brightness detection unit is
   Detecting, based on the first outside-vehicle information and the captured image, gradation number data of a target imaging area in which the target area is imaged in the captured image as brightness of the target area in front of the vehicle;
   The irradiation necessity determination unit is
   The light distribution control device according to claim 2 , further comprising: a determining unit configured to determine whether or not it is necessary to irradiate the target area with the light based on the grayscale number data of the target imaging area detected by the brightness detection unit.
4. The irradiation necessity determination unit is
   The light distribution control device according to claim 3 , wherein when it is determined that the target area is not bright based on a set condition, it is determined that irradiation of the target area with the light is necessary.
5. the gradation number data is a grayscale value corresponding to each pixel of the target imaging area,
   The irradiation necessity determination unit is
   If the average value of the grayscale values is less than a brightness determination threshold based on the set condition, it is determined that the target area needs to be irradiated with the light;
   5. The light distribution control device according to claim 4, wherein the brightness determination threshold is adjusted based on a position of the vehicle or the illumination target and map information.
6. The irradiation condition determination unit is
   The light distribution control device according to claim 1 , further comprising: determining a range in which the light is to be irradiated with respect to the headlight as the irradiation condition of the light.
7. The irradiation condition determination unit is
   The light distribution control device according to claim 1 , further comprising: determining, as the irradiation condition of the light, a range of the headlight to be irradiated with the light and an amount of light.
8. The irradiation condition determination unit is
   The light distribution control device according to claim 7 , wherein the amount of light emitted from the headlight is changed according to the brightness of the target area.
9. The light distribution control unit is
   9. The light distribution control device according to claim 1, wherein, when the irradiation necessity determination unit determines that it is not necessary to irradiate the target area with the light, the headlight is caused to return the state of irradiating the target area with the light to an initial state after a set time has elapsed.
10. A light distribution control device according to any one of claims 1 to 9,
    A light distribution control system comprising the headlight.
11. The light distribution control system according to claim 10, wherein the headlight is a variable light distribution type headlight.
12. The light distribution control system according to claim 10, wherein the headlight is a spotlight type headlight.
13. The light distribution control unit is
    13. The light distribution control system according to claim 10, wherein, when the irradiation necessity determination unit determines that it is not necessary to irradiate the target area with the light, the headlight is caused to return the state of irradiating the target area with the light to an initial state after a set time has elapsed.
14. a step of determining whether or not an illumination target is present in front of the vehicle based on first outside information related to an object present around the vehicle,
    a brightness detection unit detecting brightness ahead of the vehicle based on second outside information for determining brightness ahead of the vehicle;
    a step of an illumination necessity determination unit determining, when the illumination target presence/absence determination unit determines that the illumination target exists ahead of the vehicle, whether or not it is necessary to irradiate a target area where the illumination target exists based on the brightness ahead of the vehicle detected by the brightness detection unit;
    an illumination condition determination unit determining an illumination condition of the headlight based on a determination result by the illumination necessity determination unit as to whether or not illumination of the light to the target area is necessary;
    and a step of a light distribution control unit controlling the headlight in accordance with the illumination condition determined by the illumination condition determination unit.

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