Irradiation control device and irradiation control method

Abstract

Provided is an irradiation control device comprising: a light distribution determination unit (11) that determines whether to distribute light to a road division line of a travel lane of a vehicle in the case of rain or fog; an irradiation range calculation unit (12) that, when it is determined that light is to be distributed to the road division line, acquires road division line information indicating the position of the road division line, and calculates, as an irradiation range, a road surface including the road division line and a region that does not include the position of the center of the travel lane; and an irradiation control unit (13) that instructs vehicle headlights of the vehicle so as to irradiate the calculated irradiation range.

Description

[Technical Field]

[0001] The present disclosure relates to illumination control techniques. [Background technology]

[0002] Patent Document 1 discloses a technology relating to a vehicle headlamp device that includes a laser light source, a reflecting means that reflects the laser light emitted from the laser light source, a detecting means that detects the conditions around the vehicle, and a control means that controls the laser light source and the reflecting means so that, when the detecting means determines that visibility is poor, lanes are drawn at lane positions on the road based on lane position information on the road that has been obtained in advance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-111284 Summary of the Invention [Problem to be solved by the invention]

[0004] When illuminating lane marks on a road, i.e., road dividing lines, during poor visibility according to the teachings of Patent Document 1, road dividing lines that are far away from the vehicle equipped with the device are illuminated with a wide range of light, which causes the problem that the illuminated light is diffused by fog or raindrops, creating a curtain of light in the air (hereinafter referred to as a light curtain).

[0005] The present disclosure has been made to solve such problems, and aims to provide an illumination control technology that can improve the visibility of road markings and driving lanes on the road surface when visibility is poor. [Means for solving the problem]

[0006] One aspect of an illumination control device according to an embodiment of the present disclosure includes a light distribution determination unit that determines whether to distribute light to a road dividing line of a vehicle's driving lane in the event of rain or fog; an illumination range calculation unit that, when it is determined that light should be distributed to the road dividing line, acquires road dividing line information that indicates the position of the road dividing line and calculates an illumination range that includes the road dividing line and an area that does not include the center of the driving lane; and an illumination control unit that instructs vehicle headlights of the vehicle to illuminate the calculated illumination range. [Effects of the Invention]

[0007] According to the illumination control device according to the embodiment of the present disclosure, it is possible to improve the visibility of road markings and the road surface of the driving lane when visibility is poor. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the configuration of an irradiation control device according to a first embodiment. [Figure 2] FIG. 1 is a schematic diagram showing irradiation with beams of the same angular width. [Figure 3] FIG. 10 is a schematic diagram showing the range of the beam irradiated on a curved road. [Figure 4] FIG. 1 is a schematic diagram showing the phenomenon of beam spreading on a straight road. [Figure 5A] FIG. 2 is a diagram illustrating an example of the hardware configuration of an irradiation control device. [Figure 5B] FIG. 2 is a diagram illustrating an example of the hardware configuration of an irradiation control device. [Figure 6] 4 is a flowchart showing the operation of the irradiation control device. [Figure 7] 10 is a diagram for explaining the operation of the irradiation control device according to the first modified example. FIG. [Figure 8] 10 is a diagram for explaining the operation of the irradiation control device according to the second modification. FIG. [Figure 9] 10 is an example of a table used by an irradiation control device according to Modification 3. [Figure 10]FIG. 10 is a diagram showing an example of an illumination range determined by the table of FIG. [Figure 11] FIG. 10 is a diagram showing an example of an illumination range determined by the table of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Various embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that components with the same or similar reference numerals in the drawings have the same or similar configurations or functions, and redundant descriptions of such components will be omitted.

[0010] In addition, in this disclosure, the term "or" is used to mean an inclusive logical OR unless otherwise specified. When the term "or" is used to mean an exclusive logical OR, this will be clearly stated.

[0011] Embodiment 1 <Configuration> An illumination control device 1 according to a first embodiment of the present disclosure will be described with reference to Fig. 1. The illumination control device 1 is a device mounted on a vehicle V and controls the light distribution of the headlights of the vehicle V. As shown in Fig. 1, the illumination control device 1 is connected to a road dividing line extraction device 2, a camera 3, a weather detection device 4, and vehicle headlights 5. The illumination control device 1 is also connected to a vehicle state acquisition device (not shown) of the vehicle V, and acquires a signal indicating whether the ignition of the vehicle V is on or off from the vehicle state acquisition device.

[0012] The road dividing line extraction device 2 is a device that extracts the positions of road dividing lines of a driving lane. As an example, the road dividing line extraction device 2 acquires map information of the road on which the vehicle V is currently traveling from a car navigation system (not shown). The road dividing line extraction device 2 extracts the positions of road dividing lines located on both sides of the driving lane of the vehicle V from the acquired map information. The road dividing line extraction device 2 may also acquire the width of the driving lane and the curve radius from the acquired map information.

[0013] Alternatively, the road-dividing line extraction device 2 may acquire a forward image captured by the camera 3 and perform image processing on the acquired forward image to extract the positions of the road-dividing lines of the vehicle V's driving lane. For example, an area corresponding to a predetermined road surface may be cut out from the forward image, and an area of ​​pixels in the cut-out area having a brightness value equal to or greater than a predetermined threshold may be extracted as the road-dividing line. Furthermore, the road-dividing line extraction device 2 uses information about the installation position of the camera 3 to calculate the relative position of each extracted road-dividing line with respect to the camera 3.

[0014] The road dividing line extraction device 2 may also calculate the distance between the extracted road dividing lines as the width of the driving lane.

[0015] The road-dividing line extraction device 2 may also calculate the curve radius of the driving lane from any one of the extracted road-dividing lines. Specifically, the road-dividing line extraction device 2 calculates the curve radius of the driving lane from three points Pi(x i ,y i ) (i=1, 2, 3) and calculate the curve radius from the extracted three points using, for example, the following formula (1): In formula (1), r is the curve radius, and point (a, b) is the coordinate of the center of the circle that contains the curve. r 2 =(x i -a) 2 +(y i -b) 2 (1)

[0016] Alternatively, the road dividing line extraction device 2 may calculate the curve radius r from the following equation (2). r=(1+K·v 2 )·(L / φ) (2) In equation (2), K is the stability factor [s 2 / m 2 ], v is the left wheel speed v L and right wheel speed v Ris the vehicle speed [m / s] based on the vehicle speed r, L is the wheelbase [m], and φ is the tire steering angle [rad]. The road lane marking extraction device 2 may obtain values ​​related to these parameters from a sensor (not shown) and calculate the curve radius r.

[0017] The road-dividing line extraction device 2 outputs information including the positions of the extracted road-dividing lines as road-dividing line information to the illumination control device 1. The road-dividing line information may include map information, lane widths, and curve radii.

[0018] The camera 3 is, for example, a stereo camera. The camera 3 is disposed at an appropriate position in front of the vehicle V, and captures a forward image, which is an image in the traveling direction of the vehicle V, at a frame rate of, for example, 30 fps. The camera 3 outputs the captured forward image to the illumination control device 1. The camera 3 may also output the captured forward image to the road dividing line extraction device 2.

[0019] The weather detection device 4 is a device that detects weather such as rainfall or fog. The weather detection device 4 is, for example, a raindrop sensor that directly detects rainfall, or a status acquisition device that acquires the operating status of wipers or fog lamps that operate in bad weather such as rainfall. The weather detection device 4 outputs a result indicating the detected weather condition such as rainfall or fog to the illumination control device 1 as a weather result.

[0020] The vehicle headlights 5 are, for example, illumination devices provided on both sides of the front portion of the vehicle V. Each illumination device includes a single or multiple light sources and a driver that drives each light source. The light sources are, for example, laser light sources or LEDs (Light Emitting Diodes). The driver controls the current to the light sources based on instructions output from the illumination control device 1. The driver may also control the mirror so that the light emitted from the light source is scanned by the mirror to illuminate the illumination range. The beam width of the irradiated beam varies depending on the vehicle headlight 5 implemented, and is, for example, 0.1 degrees. The beam width, which is the control unit, is the smallest controllable beam width and may vary depending on the angle, and is set in advance in the illumination control device 1 by, for example, a user input. In this disclosure, the term "beam" refers to a beam of light.

[0021] The illumination control device 1 is a device that calculates which range of the extracted road-dividing line should be illuminated based on the outside-of-vehicle image captured by the camera 3 and the weather results output from the weather detection device 4, and issues instructions to the vehicle headlights 5 to illuminate the calculated illumination range for the road-dividing line extracted by the road-dividing line extraction device 2. To achieve this function, the illumination control device 1 includes an illumination range calculation unit 12, a light distribution determination unit 11, and an illumination control unit 13, as shown in FIG.

[0022] Before describing the specific configuration of the irradiation control device 1, problems associated with the prior art will be described in detail with reference to Figures 2 to 4. Generally, the farther away a beam is projected, the wider the beam becomes. Therefore, even when a beam of the same angular width is projected, the range of irradiation differs between when a position close to the light source is projected and when a position far from the light source is projected, and when a position far from the light source is projected, a wider range is projected when a position far from the light source is projected.

[0023] Figure 2 is a schematic diagram illustrating this. In Figure 2, beams NB and FB have the same angular width (beam width). Beam NB irradiates a position close to vehicle V, and beam FB irradiates a position far from vehicle V. As shown in Figure 2, the area on the road surface irradiated by beam FB is wider than the area on the road surface irradiated by beam NB.

[0024] Therefore, even if you try to illuminate only distant road markings, the beam will spread to the periphery of the road markings, illuminating the center of the driving lane and other road markings in addition to the one you are trying to illuminate. This is particularly noticeable on curved roads.

[0025] FIG. 3 is a schematic diagram showing the range of illumination by a beam on a curved road. In FIG. 3, the headlight of vehicle V includes, for example, a plurality of LED light sources, numbered first through sixth, where the beam from the first light source illuminates illumination block B1, the beam from the second light source illuminates illumination block B2, the beam from the third light source illuminates illumination block B3, the beam from the fourth light source illuminates illumination block B4, the beam from the fifth light source illuminates illumination block B5, and the beam from the sixth light source illuminates illumination block B6. Each light source may be a matrix-shaped light source including a plurality of sub-light sources. Instead of multiple LED light sources, a single or multiple laser light sources may be used to illuminate multiple illumination blocks B1 through B6 by scanning. As the distance from vehicle V increases, the width of the beam widens, and the beams illuminating illumination blocks B4 through B6 are diffusely reflected by fog or raindrops, creating light curtains LV4 through LV6 in the air. For example, such light veils occur in dense fog with visibility of less than 200 meters, or in heavy rain with a rainfall of 30 mm / h or more. When headlights emit white light, light veils LV4 to LV6 become white light veils. These light veils LV4 to LV6 reduce the visibility of the road surface behind the curve from the driver of vehicle V's perspective.

[0026] This beam spreading phenomenon also occurs on straight roads, but as shown in Figure 4, even if a light curtain is generated when a beam is projected along a straight road dividing line, the driving lane is not covered by the light curtain because it is straight, so no problem occurs.

[0027] The irradiation control device 1 of the present disclosure suppresses the occurrence of such a light veil. Returning to Fig. 1, the irradiation control device 1 will be described in detail.

[0028] (Light distribution determination unit) The light distribution determination unit 11 determines whether to distribute light to the road dividing line of the vehicle V's driving lane based on the forward image output by the camera 3 and the weather results output by the weather detection device 4. Based on the forward image output by the camera 3, the light distribution determination unit 11 detects, for example, a decrease in the luminance of the road dividing line and a decrease in the luminance ratio between the road dividing line and an area other than the road dividing line. Furthermore, based on the weather results output by the weather detection device 4, the light distribution determination unit 11 detects rainfall, the occurrence of fog, wiper operation, and fog lamp illumination. The light distribution determination unit 11 determines to distribute light to the road dividing line based on all or part of these detection results. If the light distribution determination unit 11 determines to distribute light to the road dividing line, it outputs the determination result indicating that light should be distributed to the road dividing line to the illumination range calculation unit 12 as a light distribution determination.

[0029] (Irradiation range calculation section) When the illumination range calculation unit 12 determines that light should be distributed to the road dividing line, it acquires road dividing line information indicating the position of the road dividing line output from the road dividing line extraction device 2, and calculates the road surface including the road dividing line and an area that does not include the center position of the driving lane as the illumination range.

[0030] The illumination range can be calculated, for example, as follows. First, the illumination range calculation unit 12 divides the extracted road-dividing lines into multiple road-dividing line segments. For example, the illumination range calculation unit 12 divides the road-dividing lines using map information obtained from the road-dividing line extraction device 2. More specifically, the illumination range calculation unit 12 draws perpendicular lines perpendicular to a virtual line represented by the center point of the driving lane obtained as point cloud information from the map information, from each point on the virtual line to the road-dividing line, and defines a section including consecutive intersections of the road-dividing line and the perpendicular lines corresponding to multiple consecutive points on the virtual line, for example, two points, as one road-dividing line segment. Note that the virtual line may be calculated as a line connecting the centers of the road-dividing lines.

[0031] The illumination area calculation unit 12 generates a set of the divided road-dividing line segments as a candidate illumination area. For example, in the example of FIG. 3, the illumination area calculation unit 12 divides the extracted road-dividing line into road-dividing line segments S1 to S6. The set of road-dividing line segments S1 to S6 is the candidate illumination area. In this disclosure, the areas that include the road-dividing line segments S1 to S6 and are illuminated by the light source are referred to as illumination blocks B1 to B6, respectively. Therefore, the set of illumination blocks B1 to B6 may also be referred to as a candidate illumination area.

[0032] Furthermore, the illumination range calculation unit 12 determines whether the center position of the driving lane is included in each illumination block B (B1 to B6). The center position of the driving lane may be acquired from map information or may be calculated as the midpoint of the extracted road dividing lines. The illumination range calculation unit 12 determines to exclude the illumination block B (B1 to B6) that is determined to include the center position of the driving lane from the candidate illumination range.

[0033] The illumination range calculation unit 12 determines whether or not the center position of the driving lane is included for all illumination blocks, excludes the illumination blocks determined to be excluded from the candidate illumination range from the candidate illumination range, and calculates the area including the remaining illumination blocks as the final illumination range. The illumination range calculation unit 12 outputs the calculated illumination range to the illumination control unit 13.

[0034] Instead of such a method of determining whether the center position of the driving lane is included within each illumination block B, it may be determined whether the illumination block B includes a position that is at least a predetermined first length away from the corresponding road dividing line segment S (S1 to S6) toward the driving lane. As one example, the predetermined first length is half the width of the driving lane. As another example, the predetermined first length is one-third the width of the driving lane. The predetermined first length may be any other length as long as it is half the width of the driving lane or less.

[0035] (Irradiation control unit) When the illumination control unit 13 receives the illumination range output from the illumination range calculation unit 12, it instructs the vehicle headlight 5 to illuminate the illumination range calculated by the illumination range calculation unit 12. The vehicle headlight 5 illuminates the calculated illumination range in accordance with the instruction from the illumination control unit 13.

[0036] Next, an example of the hardware configuration of the irradiation control device 1 will be described with reference to Figures 5A and 5B. Each function of the irradiation control device 1 is realized by a processing circuitry. The processing circuitry may be a dedicated processing circuit 100a as shown in Figure 5A, or a processor 100b that executes a program stored in a memory 100c as shown in Figure 5B.

[0037] When the processing circuitry is a dedicated processing circuit 100a, the dedicated processing circuit 100a 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 thereof. The functions of the irradiation control device 1 may be realized by a plurality of separate processing circuits, or the functions of the irradiation control device 1 may be realized together by a single processing circuit.

[0038] When the processing circuitry is a processor 100b, the functions of the irradiation control device 1 are realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 100c. The processor 100b realizes the functions of the irradiation control device 1 by reading and executing the programs stored in the memory 100c. Examples of the memory 100c include non-volatile or volatile semiconductor memory such as RAM (random access memory), ROM (read-only memory), flash memory, EPROM (erasable programmable read-only memory), and EEPROM (electrically erasable programmable read-only memory), as well as magnetic disks, flexible disks, optical disks, compact disks, minidisks, and DVDs.

[0039] It is also possible to implement some of the functions of the irradiation control device 1 using dedicated hardware, and other functions using software or firmware. In this way, the processing circuit can implement the functions of the irradiation control device 1 using hardware, software, firmware, or a combination of these.

[0040] <Operation> Next, the operation of the irradiation control device 1 will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the operation of the irradiation control device 1. A series of processes shown in the flowchart of Fig. 6 is executed at predetermined timings during the period from when the ignition of the vehicle V is turned on to when it is turned off.

[0041] In step ST1, the light distribution determination unit 11 determines whether or not to distribute light to the road dividing lines at a predetermined timing. If it is determined that light distribution is not to be performed, the process returns to step ST1, and the light distribution determination unit 11 repeats the process of step ST1 at a predetermined timing. If it is determined that light distribution is not to be performed, the process proceeds to step ST2.

[0042] In step ST2, the illumination range calculation unit 12 acquires the positions of the road-dividing lines extracted by the road-dividing line extraction device 2.

[0043] In step ST3, the illumination area calculation unit 12 divides the extracted road-dividing line into a plurality of road-dividing line segments and calculates a candidate illumination area, which is a set of the divided road-dividing line segments. The set of road-dividing line segments is also a set of illumination blocks.

[0044] In step ST4, the irradiation range calculation unit 12 repeats the evaluation loop to evaluate whether or not each irradiation block is to be included in the final irradiation range for all irradiation blocks included in the candidate irradiation ranges.

[0045] In step ST5, the illumination range calculation unit 12 determines whether a predetermined position is illuminated. Specifically, this determination may be made by determining whether the center position of the driving lane is included in the illumination block to be evaluated. Alternatively, it may be made by determining whether a position that is at least a predetermined first length away from the road dividing line segment S (S1 to S6) toward the side where the driving lane is located is included. If it is determined that the predetermined position is illuminated, the process proceeds to step ST6, and the illumination range calculation unit 12 excludes the illumination block to be evaluated from the candidate illumination ranges. On the other hand, if it is not determined that the predetermined position is illuminated, the evaluation loop is repeated, and the illumination range calculation unit 12 evaluates other illumination blocks that have not yet been evaluated.

[0046] When the evaluation of all the irradiation blocks determined as the candidate irradiation areas is completed, the evaluation loop is completed and the process proceeds to step ST7. In step ST7, the irradiation area calculation unit 12 calculates the candidate irradiation area after the processing of the evaluation loop is completed as the final irradiation area and outputs the calculated irradiation area to the irradiation control unit 13.

[0047] In step ST8, the illumination control unit 13 instructs the vehicle headlight 5 to illuminate the illumination range calculated by the illumination range calculation unit 12.

[0048] In the example of FIG. 3, it is assumed that illumination blocks B1 to B6 are the provisional illumination range. The illumination range calculation unit 12 determines that, for example, B4 to B6 among the illumination blocks B1 to B6, a predetermined position (for example, the center position of the driving lane) is illuminated. When such a determination is made, the illumination range calculation unit 12 excludes the illumination blocks B4 to B6 from the illumination range. Upon completion of the evaluation loop, the illumination blocks B1 to B3 that were not excluded become the final illumination range, and the illumination control unit 13 instructs the vehicle headlight 5 to illuminate the illumination blocks B1 to B3. This suppresses the occurrence of light veils LV4 to LV6, thereby ensuring the visibility of the road dividing lines included in the illumination blocks B1 to B3 and improving the visibility of the road surface of the driving lane during poor visibility.

[0049] <Modification> In the first embodiment, instead of the method for calculating the irradiation range as described above, the irradiation range may be calculated by a method as described in the following modified examples. Three modified examples will be described below.

[0050] <Variation 1> Modification 1 will be described with reference to FIG. 7. In the first embodiment, an example was described in which it was determined whether a position that is at least a predetermined first length away from the road-dividing line segment S (S1 to S6) corresponding to each illumination block B toward the side where the driving lane is located is included. In Modification 1, the illumination range calculation unit 12 may determine whether there is a possibility that such a position is included. The presence or absence of such a possibility may be determined based on whether a road-dividing line segment that is at least a predetermined length L (a second length) or a predetermined angle A away from the forward direction F of the vehicle headlight 5 to either the left or right is illuminated. The example in FIG. 7 illustrates a case in which a road-dividing line segment that is at least a predetermined length L or a predetermined angle A away from the forward direction F of the vehicle headlight 5 to the left is illuminated. As the length L or angle A increases, the curvature of the driving lane becomes stronger, and therefore, there is a higher possibility that a position that is at least a predetermined first length away from the road-dividing line segment S (S1 to S6) toward the side where the driving lane is located is included. Therefore, when illuminating a road-dividing line segment that is at least the length L or angle A away, it may be determined that a position at least a predetermined first distance away from the road-dividing line segment S (S1 to S6) toward the driving lane may be included, and the corresponding illumination block B may be excluded from the candidate illumination range. The example in Fig. 7 illustrates a case in which illumination range block B7 including road-dividing line segment S7 and illumination range block B8 including road-dividing line segment S8, both of which are at least the predetermined length L or angle A away, are excluded from the candidate illumination range.

[0051] The predetermined length L (second length) or the predetermined angle A may be fixed or variable. For example, the length L or angle A may be variable depending on the value of the curve radius or the width of the driving lane. When the length L or angle A is variable, the illumination range can be more appropriately determined depending on the degree of the curve or the width of the driving lane.

[0052] <Variation 2> Variation 2 will be described with reference to FIG. 8. The illumination range calculation unit 12 may determine whether or not the above-described possibility exists based on whether or not to illuminate a road-dividing line segment corresponding to a beam width equal to or greater than a predetermined threshold. The threshold is, for example, 2°. Since the width of the illumination range block increases as the curve becomes sharper, if the width of the illumination range block is equal to or greater than a predetermined width—in other words, if a road-dividing line segment corresponding to a beam width equal to or greater than a predetermined threshold—is to be illuminated, the illumination range block or the road-dividing line segment may not be illuminated. FIG. 8 illustrates an example in which an illumination range block B9 including a road-dividing line segment S9 corresponding to a beam width BW equal to or greater than a predetermined threshold is excluded from the candidate illumination ranges.

[0053] <Variation 3> The third modification will be described with reference to FIGS. 9 to 11. The illumination range calculation unit 12 may calculate the illumination range by referring to a table. When calculating the illumination range by referring to a table, the illumination range calculation unit 12 of the illumination control device 1 refers to a table in which illumination ranges are predetermined according to combinations of lane widths and curve radii, and acquires the illumination range corresponding to the combination of lane width and curve radii included in the road dividing line information. Such a table may be stored in, for example, the memory 100c, and the illumination range calculation unit 12 accesses the memory 100c to refer to the table. FIG. 9 shows an example of a table in which illumination ranges are predetermined according to combinations of lane widths and curve radii. In the table of FIG. 9, the lane width column indicates cases of 3.1 to 3.2 [m] and cases of 3.2 to 3.4 [m]. Furthermore, the curve radius column indicates cases of 100 to 110 [m] and cases of 200 to 210 [m].

[0054] Row r1 indicates that when the lane width is 3.2 to 3.4 m and the curve radius is 200 to 210 m, the first illumination range is a 0.70° range centered at -7.25° on the left and right, the second illumination range is a 0.50° range centered at -7.85° on the left and right, the third illumination range is a 0.90° range centered at -8.55° on the left and right, and the fourth illumination range is a 0.90° range centered at -9.45° on the left and right. Note that the negative signs attached to the numerical values ​​of the left and right positions [°] indicate the left and right directions when viewed forward from vehicle V, respectively.

[0055] Row r2 indicates that when the lane width is 3.2 to 3.4 m and the curve radius is 100 to 110 m, the first illumination range is a 1.50° range centered at -12.95° on the left and right, the second illumination range is a 1.70° range centered at -14.55° on the left and right, and the third illumination range is a 1.70° range centered at -16.25° on the left and right. In row r2, the value corresponding to the fourth illumination range is blank, indicating that no illumination is to be performed. Because illuminating the fourth illumination range could potentially irradiate the center of the driving lane, creating a potential veil of light, the fourth illumination range is not illuminated.

[0056] In this way, the table defines the illumination range according to the combination of lane width and curve radius, and as is clear from comparing rows r1 and r2, even if the lane width is the same, if the curve radius is shorter, the illumination range is defined to illuminate a narrower area.

[0057] The illumination range calculation unit 12 refers to a table in which such illumination ranges are predetermined, and acquires the illumination range corresponding to the calculated combination of the width of the driving lane and the curve radius.

[0058] According to the acquired illumination range, the illumination control unit 13 instructs the vehicle headlight 5 to illuminate the illumination range. Examples of the illumination range are shown in Fig. 10 and Fig. 11. Fig. 10 and Fig. 11 show light distribution patterns formed on a virtual vertical screen (a plane parallel to the forehead) placed at a predetermined position in front of the vehicle headlight 5. Fig. 10 shows a case where the illumination range defined in row r1 is illuminated, and Fig. 11 shows a case where the illumination range defined in row r2 is illuminated.

[0059] When calculating the illumination range using the methods of these variants 1 to 3, the occurrence of light curtains LV4 to LV6 is suppressed, as in embodiment 1, so that when visibility is poor, the visibility of the road dividing lines included in illumination blocks B1 to B3 is ensured and the visibility of the road surface of the driving lane is improved.

[0060] It is possible to combine the embodiments, and to modify or omit each embodiment as appropriate. [Industrial Applicability]

[0061] The illumination control device of the present disclosure can be used as a control device for controlling the area illuminated by the headlights of a vehicle. [Explanation of symbols]

[0062] 1 illumination control device, 2 road dividing line extraction device, 3 camera, 4 weather detection device, 5 vehicle headlight, 11 light distribution determination unit, 12 illumination range calculation unit, 13 illumination control unit, 100a processing circuit, 100b processor, 100c memory.

Claims

1. a light distribution determining unit that determines whether to distribute light to a road dividing line of a vehicle's travel lane in the case of rain or fog; an illumination range calculation unit that, when it is determined that light should be distributed to the road dividing line, acquires road dividing line information indicating the position of the road dividing line, and calculates an illumination range that includes the road dividing line and an area that does not include the center of the driving lane; an illumination control unit that instructs a vehicle headlight of the vehicle to illuminate the calculated illumination range; An irradiation control device comprising:

2. the illumination range calculation unit divides each of the acquired road-dividing lines into a plurality of road-dividing line segments, and calculates candidate illumination ranges including the divided road-dividing line segments; determining whether, when a road-dividing line segment included in the calculated candidate illumination range is illuminated, a position that is at least a predetermined first distance away from the road-dividing line segment toward the driving lane is illuminated or is likely to be illuminated; when it is determined that a position that is at least the first distance is illuminated or has the possibility of being illuminated, the illumination range is calculated by excluding the road-dividing line segment to be determined from the calculated candidate illumination range. The irradiation control device according to claim 1 .

3. the illumination range calculation unit, when the candidate illumination range includes a road-dividing line segment that is located to the left or right of the front of the vehicle headlight by a predetermined second length or a predetermined angle or more, determines that there is the possibility and excludes the included road-dividing line segment from the candidate illumination range. The irradiation control device according to claim 2 .

4. The value of the predetermined second length or the predetermined angle is variable depending on the width or the curve radius of the driving lane. The irradiation control device according to claim 3.

5. the illumination range calculation unit, when the candidate illumination range includes a road-dividing line segment corresponding to a beam width equal to or greater than a predetermined threshold, determines that there is the possibility and excludes the included road-dividing line segment from the candidate illumination range. The irradiation control device according to claim 2 .

6. The road division line information includes a width of a lane in which the vehicle is traveling and a curve radius. the illumination range calculation unit acquires a range corresponding to a combination of the width of the driving lane and the curve radius by referring to a table in which ranges corresponding to combinations of width and radius are predetermined, and calculates the acquired range as the illumination range; The irradiation control device according to claim 1 .

7. The first length is half the width of the travel lane. The irradiation control device according to any one of claims 2 to 5.

8. An illumination control method performed by an illumination control device including a light distribution determination unit, an illumination range calculation unit, and an illumination control unit, a step of determining whether the light distribution determination unit should distribute light to a road dividing line of a vehicle's travel lane in the case of rain or fog; when it is determined that light should be distributed to the road dividing line, the illumination range calculation unit acquires road dividing line information indicating the position of the road dividing line, and calculates, as an illumination range, the road surface including the road dividing line and an area excluding the center position of the driving lane; the illumination control unit instructing a vehicle headlight of the vehicle to illuminate the calculated illumination range; An irradiation control method comprising:

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