Vehicle headlight control device and vehicle headlight control method

Abstract

A vehicle headlight control device (20, 30) is provided with: a division line information acquisition unit (21) that acquires information pertaining to the position of a division line (L1, L3) on a road surface with which a vehicle (S1) is in contact; a moving body detection unit (23) that detects a moving body (S1) present ahead of the vehicle; and an irradiation control unit (24) that, when the moving body is not detected by the moving body detection unit, controls a headlight (14) of the vehicle so that the irradiation mode of light with respect to the division line on the road surface is a first mode, and when the moving body detection unit has detected the moving body, controls the headlight so that the irradiation mode for the light with respect to the division line on the road surface is a second mode different from the first mode.

Description

Vehicle headlight control device and vehicle headlight control method

[0001] The present disclosure relates to a vehicle headlight control device and a vehicle headlight control method.

[0002] A conventional vehicle lighting system has been disclosed that forms a light distribution pattern using vehicle lamps that does not illuminate lane marks on the opposite lane side when driving in the rain (see Patent Document 1). This vehicle lighting system improves the visibility of lane marks on the vehicle's own lane by illuminating lane marks on the vehicle's own lane side with light, while preventing glare that is caused by light directed toward lane marks on the opposite lane side being reflected by the road surface by not illuminating lane marks on the opposite lane side.

[0003] Japanese Patent Application Laid-Open No. 2015-003628

[0004] Generally, when light is irradiated onto lane markings, the visibility of the lane markings can be improved compared to when no light is irradiated. Furthermore, even when driving in the rain, depending on the surrounding conditions, irradiating the lane markings with light may not cause glare to drivers of other vehicles. However, the vehicle lighting system described in Patent Document 1 has a problem in that it cannot irradiate the lane markings with light according to the surrounding conditions.

[0005] The present disclosure aims to solve the above-mentioned problem and to provide a vehicle headlight control device and a vehicle headlight control method that can irradiate light onto marking lines in a manner that corresponds to the situation around the vehicle.

[0006] The vehicle headlight control device of the present disclosure is characterized by comprising: a marking line information acquisition unit that acquires information regarding the position of marking lines on the road surface on which the vehicle is in contact; a moving object detection unit that detects a moving object present ahead of the vehicle; and an illumination control unit that, when no moving object is detected by the moving object detection unit, controls the vehicle's headlights so that the illumination pattern of light onto the marking lines on the road surface is a first pattern, and, when a moving object is detected by the moving object detection unit, controls the headlights so that the illumination pattern of light onto the marking lines on the road surface is a second pattern different from the first pattern.

[0007] According to the present disclosure, it is possible to irradiate the lane markings with light in a manner that depends on whether or not a moving object present in front of the vehicle has been detected.

[0008] 1 is a block diagram showing the configuration of a vehicle according to a first embodiment. 2 is a block diagram showing an example of the hardware configuration of a headlight control device according to the first embodiment. 3 is a flowchart showing processing performed by the headlight control device according to the first embodiment. 4 is a schematic plan view showing a state in which a headlight is irradiating light onto a lane marking in a first manner by the headlight control device according to the first embodiment. 5 is a schematic plan view showing a state in which a headlight is irradiating light onto a lane marking in a second manner when an oncoming vehicle is detected by the headlight control device according to the first embodiment. 6 is a schematic plan view showing a state in which a headlight is irradiating light onto a lane marking in a second manner when a leading vehicle is detected by the headlight control device according to the first embodiment. 7 is a schematic plan view showing a state in which a headlight is irradiating light onto a lane marking in a second manner when an oncoming vehicle is detected by the headlight control device according to the second embodiment. 8 is a schematic plan view showing a state in which a headlight is irradiating light onto a lane marking in a second manner when an oncoming vehicle is detected by the headlight control device according to the third embodiment. 1 is a schematic diagram in a plan view showing a state in which a headlight is irradiating light onto a lane marking in a second manner when an oncoming vehicle is detected by a headlight control device according to embodiment 4. FIG. 2 is a block diagram showing the configuration of a vehicle according to embodiment 5. FIG. 3 is a flowchart showing processing performed by a headlight control device according to embodiment 5. FIG. 4 is a schematic diagram in a side view showing a state in which a headlight is irradiating light onto a lane marking in a first manner when an oncoming vehicle is detected by a headlight control device according to embodiment 5. FIG. 5 is a schematic diagram in a side view showing a state in which a headlight is irradiating light onto a lane marking in a second manner when an oncoming vehicle is detected by a headlight control device according to a modification of embodiment 5.

[0009] Embodiments of the present disclosure will be described in detail below with reference to the drawings. Embodiment 1. First, a schematic configuration of a vehicle according to embodiment 1 will be described with reference to FIG. 1. FIG. 1 is a block diagram illustrating the configuration of the vehicle according to embodiment 1. As shown in FIG. 1, for example, the vehicle according to embodiment 1 includes an exterior information acquisition unit 11, a vehicle information acquisition unit 12, a map information acquisition unit 13, headlights 14, and a headlight control device 20. The headlight control device 20 is electrically connected to the exterior information acquisition unit 11, the vehicle information acquisition unit 12, the map information acquisition unit 13, and the headlights 14 so as to enable transmission and reception of information, and controls the illumination of light by the headlights 14 based on information from the exterior information acquisition unit 11, the vehicle information acquisition unit 12, and the map information acquisition unit 13. Note that, in the vehicle according to embodiment 1, some of these functions may be provided in a device outside the vehicle via a network. Furthermore, in embodiment 1, the forward direction is defined as the direction directly in front of a driver seated in a driving position in the driver's seat of the vehicle as the host vehicle, and the front-rear, up-down, left-right, and right directions are defined based on this.

[0010] The outside-vehicle information acquisition unit 11 acquires information about objects present outside the vehicle. For example, the outside-vehicle information acquisition unit 11 is configured with any one of an infrared camera, a visible light camera, a millimeter-wave radar, a LiDAR (Light Detection and Ranging), and an ultrasonic sensor, or a combination of a plurality of these. For example, the outside-vehicle information acquisition unit 11 acquires information about the position of another vehicle as a moving object present outside the vehicle. Furthermore, for example, the outside-vehicle information acquisition unit 11 acquires information about the road surface on which the vehicle is running. Specifically, the outside-vehicle information acquisition unit 11 acquires information about the road surface as image information by capturing an image of the road surface using an infrared camera, a visible light camera, or the like.

[0011] Furthermore, for example, the vehicle exterior information acquisition unit 11 acquires information about the road surface condition by detecting water droplets splashed up by the vehicle using an ultrasonic sensor when the vehicle travels on a wet road surface. Furthermore, for example, the vehicle exterior information acquisition unit 11 acquires information about the road surface condition by detecting water droplets and water films adhering to the surface of the vehicle and water droplets and water films on the road surface using an ultrasonic sensor based on the vibration intensity of ultrasonic waves. Furthermore, for example, the vehicle exterior information acquisition unit 11 acquires information about water droplets adhering to the outer surface of the vehicle's windshield by capturing an image of the vehicle's windshield using an infrared camera, a visible light camera, or the like. In the first embodiment, the ultrasonic sensor that detects water droplets splashed up by the vehicle when the vehicle travels on a wet road surface and the camera that captures an image of the vehicle's windshield with water droplets adhering thereto constitute a water detection unit that detects water caused by rainfall.

[0012] The vehicle information acquisition unit 12 acquires information about the vehicle. For example, the vehicle information acquisition unit is configured with one or a combination of a sensor that detects the operation of the wipers of the vehicle, a sensor that detects the adhesion of raindrops to the windshield of the vehicle, a sensor that detects the opening and closing of the windows of the vehicle, a sensor that detects the on / off of the fog lamps of the vehicle when the headlights 14 are provided independently of the fog lamps, and a sensor that detects the traveling speed of the vehicle. Note that these various sensors may be attached to the vehicle body during the vehicle production stage, or may be attached to the vehicle body by the vehicle user.

[0013] In the first embodiment, the sensor that detects raindrops on the windshield of the host vehicle constitutes a water detection unit that detects water due to rainfall. For example, the sensor that detects raindrops on the windshield of the host vehicle is configured to irradiate the outer surface of the windshield of the host vehicle with LED light and detect the presence of raindrops based on whether the intensity of the light reflected from the windshield is greater than a preset threshold. The reflected light is weaker when raindrops are present on the windshield than when there are no raindrops present. The sensor that detects raindrops on the windshield of the host vehicle may also be configured to detect the presence of raindrops based on the vibration of the windshield when raindrops collide with the outer surface of the windshield of the host vehicle. Furthermore, the operation of the windshield wipers, the opening and closing of the windows of the host vehicle, and the turning on and off of the fog lights of the host vehicle are all operations that are affected by the weather and can be considered to be weather-related operations of the host vehicle. In addition, the vehicle information acquisition unit 12 may be configured to acquire information indicating the operation of the vehicle by directly detecting the operation of the vehicle, or may be configured to acquire information indicating the operation of the vehicle by detecting the operation of the vehicle by an occupant of the vehicle.

[0014] The map information acquisition unit 13 acquires map information about the surrounding area of ​​the vehicle. For example, the map information acquisition unit 13 may be configured with a car navigation system that uses a positioning system such as a GPS or a locator, and acquires information indicating the position of the vehicle and references information stored in a storage device of the vehicle to acquire map information about the surrounding area of ​​the vehicle. Alternatively, for example, the map information acquisition unit 13 may be configured with a wireless communication device that acquires information from an external server via a communication network, and acquires map information about the surrounding area of ​​the vehicle from the external server. For example, the map information acquisition unit 13 acquires surrounding map information including information such as the shape of roads around the vehicle, the positions of lane markings on the roads, the types of lane markings on the roads, and the position of the vehicle.

[0015] The headlights 14 emit light ahead of the vehicle. Specifically, the headlights 14 are headlights for illuminating road markings on the road surface on which the vehicle is driving. For example, the headlights 14 include multiple light sources, such as LEDs or incandescent bulbs, a lens for focusing or diffusing the light from the light sources, and a reflector for reflecting the light from the lens. The headlights 14 emit the light reflected by the reflector in a predetermined range and direction. Note that the headlights 14 may be configured as independent headlights for driving that emit light onto the driving route ahead, passing headlights that emit light onto a range of the driving route closer to the vehicle than the driving headlights, and sidelights that notify surrounding vehicles of the vehicle's width, or may be configured to have some or all of the functions of the headlights for driving, passing, and sidelights.

[0016] The headlight 14 is configured to be able to change the light irradiation range, light irradiation direction, and brightness of the irradiated light. The headlight 14 is configured to be able to change one or more of the light irradiation range, light irradiation direction, and light brightness by changing which of a plurality of light sources is turned on. Furthermore, for example, the headlight 14 is configured to be able to change one or more of the light irradiation range, light irradiation direction, and light brightness by changing the position or orientation of at least one of the lens and the reflector. For example, the reflector is supported rotatably and is configured to be able to change its position and orientation by power from a drive source. Furthermore, for example, the headlight 14 is configured to be able to change the brightness of the irradiated light by at least one of selecting a light source to be emitted from a plurality of light sources and changing the power supplied to the light source. Note that in the first embodiment, the irradiation direction means the direction from the portion of the headlight 14 from which light is emitted toward the center of the light irradiation range.

[0017] As shown in FIG. 1 , the headlight control device 20 includes a lane marking information acquisition unit 21, a road surface condition estimation unit 22, a vehicle detection unit 23, and an illumination control unit 24. The lane marking information acquisition unit 21 acquires information regarding the positions of lane markings on the road surface on which the host vehicle is adjacent. For example, the lane marking information acquisition unit 21 acquires information regarding the positions of lane markings on the road surface on which the host vehicle is adjacent based on information from the outside-vehicle information acquisition unit 11. Specifically, the lane marking information acquisition unit 21 acquires information regarding the positions of lane markings on the road surface on which the host vehicle is adjacent relative to the host vehicle based on image information acquired when the outside-vehicle information acquisition unit 11 captures an image of the outside of the host vehicle. Furthermore, for example, the lane marking information acquisition unit 21 acquires information regarding the positions of lane markings on the road surface on which the host vehicle is adjacent based on map information of the area around the host vehicle from the map information acquisition unit 13. Note that the lane marking information acquisition unit 21 may be configured to acquire information regarding the type of lane marking in addition to information regarding the positions of the lane markings. Furthermore,

[0018] The road surface condition estimation unit 22 estimates whether the road surface on which the host vehicle is in contact is wet. For example, the road surface condition estimation unit 22 estimates whether the road surface on which the host vehicle is in contact is wet based on information from the outside-vehicle information acquisition unit 11. Specifically, the road surface condition estimation unit 22 irradiates the road surface with headlight light and estimates whether the road surface is wet based on whether the intensity of the light reflected from the road surface is greater than a preset threshold. When the road surface is wet, the reflected light is weaker than when the road surface is not wet because diffuse reflection from the road surface and lane markings is suppressed. Furthermore, for example, the road surface condition estimation unit 22 estimates whether the road surface on which the host vehicle is in contact is wet based on image information acquired when the outside-vehicle information acquisition unit 11 captures an image of the outside of the host vehicle. Furthermore, for example, the road surface condition estimation unit 22 estimates whether the road surface on which the host vehicle is in contact is wet based on the detection result of water droplets splashed up when the host vehicle travels on a wet road surface by the vehicle exterior information acquisition unit 11. Specifically, the road surface condition estimation unit 22 estimates that the road surface on which the host vehicle is in contact is wet if the detection result of water droplets splashed up by the vehicle exterior information acquisition unit 11 when the host vehicle travels on a wet road surface indicates that the detection frequency of water droplets exceeds a preset frequency.

[0019] Furthermore, for example, the road surface condition estimation unit 22 estimates whether the road surface on which the vehicle is in contact is wet based on the detection result of water droplets adhering to the outside of the windshield of the vehicle by the vehicle exterior information acquisition unit 11. Specifically, the road surface condition estimation unit 22 estimates that the road surface on which the vehicle is in contact is wet when the detection result of water droplets adhering to the outside of the windshield of the vehicle by the vehicle exterior information acquisition unit 11 indicates that the amount of water droplets exceeds a predetermined amount.

[0020] Furthermore, for example, the road surface condition estimation unit 22 estimates whether or not the road surface on which the host vehicle is in contact is wet, based on information from the vehicle information acquisition unit 12. Specifically, the road surface condition estimation unit 22 estimates whether or not the road surface on which the host vehicle is in contact is wet, based on the detection result of the operation of the wipers of the host vehicle from the vehicle information acquisition unit 12. More specifically, the road surface condition estimation unit 22 estimates that the road surface on which the host vehicle is in contact is wet, when the detection result of the operation of the wipers of the host vehicle from the vehicle information acquisition unit 12 indicates that the frequency of wiper use has exceeded a preset frequency.

[0021] Furthermore, for example, the road surface condition estimation unit 22 estimates that the road surface on which the host vehicle is in contact is wet when the detection result of the wiper operation of the host vehicle from the vehicle information acquisition unit 12 indicates that the wipers have been operating continuously for a predetermined first time or more. Furthermore, for example, the road surface condition estimation unit 22 estimates that the road surface on which the host vehicle is in contact is wet when the detection result of the wiper operation of the host vehicle from the vehicle information acquisition unit 12 indicates that the wipers have stopped operating after continuing to operate for a predetermined first time or more and that the elapsed time since the wipers stopped operating is within a predetermined second time. For example, the first time is 10 minutes, and the second time is 1 hour. The road surface condition estimation unit 22 may be configured to set the length of the second time depending on the length of time the wipers have been operating continuously.

[0022] Furthermore, for example, the road surface condition estimation unit 22 estimates whether the road surface on which the vehicle is in contact is wet based on the detection result of the vibration of the windshield from the vehicle information acquisition unit 12. Specifically, the road surface condition estimation unit 22 estimates that the road surface on which the vehicle is in contact is wet when the detection result of the vibration of the windshield from the vehicle information acquisition unit 12 indicates that a preset number of raindrops or more are colliding with the windshield.

[0023] For example, the road surface condition estimation unit 22 estimates whether the road surface on which the host vehicle is on is wet based on the detection result of the window opening / closing operation from the vehicle information acquisition unit 12. Specifically, the road surface condition estimation unit 22 estimates that the road surface on which the host vehicle is on is not wet when the detection result of the window opening / closing operation from the vehicle information acquisition unit 12 indicates that the window of the host vehicle has been open for a predetermined period of time or more, for example, the past 30 minutes or more. For example, the road surface condition estimation unit 22 estimates whether the road surface on which the host vehicle is on is wet based on the detection result of the fog lamp operation from the vehicle information acquisition unit 12. Specifically, the road surface condition estimation unit 22 estimates that the road surface on which the host vehicle is on is wet when the detection result of the fog lamp operation from the vehicle information acquisition unit 12 indicates that the fog lamp is on.

[0024] The vehicle detection unit 23, which serves as a moving object detection unit, detects another vehicle present ahead of the host vehicle based on information from the outside-vehicle information acquisition unit 11. The vehicle detection unit 23 also estimates the traveling direction of the other vehicle relative to the traveling direction of the host vehicle based on a change over time in the position of the other vehicle acquired from one or more of the outside-vehicle information acquisition unit 11, the vehicle information acquisition unit 12, and the map information acquisition unit 13. For example, the vehicle detection unit 23 estimates the traveling direction of the other vehicle relative to the traveling direction of the host vehicle based on the detection result of the other vehicle acquired by the outside-vehicle information acquisition unit 11 and the traveling speed of the host vehicle acquired by the vehicle information acquisition unit 12 or the change over time in the position of the host vehicle acquired by the map information acquisition unit 13. Note that in the first embodiment, the phrase "detecting another vehicle" includes both "detecting whether or not another vehicle is present within a detectable range" and "detecting whether or not another vehicle is present within a preset range."

[0025] The illumination control unit 24 has an illumination direction control unit 241 and an illumination mode control unit 242, and controls the headlights 14 based on information acquired by the lane marking information acquisition unit 21, the road surface condition estimation unit 22, and the vehicle detection unit 23. The illumination direction control unit 241 sets the illumination direction of the headlights 14 based on information about the positions of lane markings around the vehicle acquired by the lane marking information acquisition unit 21, so that the direction of illumination of light from the headlights 14 is directed toward the lane markings on the road surface.

[0026] The illumination direction control unit may be configured to set the illumination direction of the headlights 14 so that the light illumination range changes based on at least one of the position of the other vehicle relative to the host vehicle and the speed of the other vehicle relative to the host vehicle. For example, the illumination direction control unit 241 may be configured to set the illumination direction of the headlights 14 so that, when the host vehicle is moving at a first speed, the tip of the light illumination range of the headlights 14 is positioned further forward than when the host vehicle is moving at a second speed that is lower than the first speed, based on information about the positions of the lane markings around the host vehicle acquired by the lane marking information acquisition unit 21 and information about the host vehicle's moving speed acquired by the vehicle information acquisition unit 12. The illumination mode control unit 242 controls the illumination mode of the headlights 14 based on the information acquired by the vehicle detection unit 23 and the illumination direction set by the illumination direction control unit 241.

[0027] Generally, when the road surface is wet due to rainfall or the like, the visibility of road markings on the road surface may be reduced compared to when the road surface is not wet. Therefore, when the road surface is wet, it is desirable to improve the visibility of the road markings by illuminating the road surface with light from headlights or the like. However, when light is irradiated onto the road surface by headlights, depending on the illumination mode of the light, the headlight light may be reflected off the road surface and directly or indirectly illuminate the occupants of other vehicles and optical sensors of other vehicles, causing glare for the drivers of other vehicles.

[0028] For example, if the road surface is wet and there is an oncoming vehicle ahead, and the headlights shine light onto a marking line on the oncoming vehicle's side relative to the vehicle's own vehicle, the light from the headlights reflected by the road surface may reach the eyes of the driver of the oncoming vehicle, causing glare to the driver.Furthermore, if the road surface is wet and there is an oncoming vehicle ahead, and the headlights shine light onto a marking line on the oncoming vehicle's side relative to the vehicle's own vehicle, the light from the headlights reflected by the road surface may reach an optical sensor, such as a camera, directly in the oncoming vehicle, preventing the optical sensor from fully functioning.

[0029] Furthermore, when the road surface is wet and there is a preceding vehicle ahead, if the headlights shine light onto the lane markings on the right and left sides of the vehicle, i.e., onto either of the lane markings on both sides of the vehicle, the light from the headlights reflected by the road surface may indirectly reach the eyes of the driver of the oncoming vehicle via the rearview mirror of the preceding vehicle, causing glare to the driver.Furthermore, for example, when the road surface is wet and there is a preceding vehicle ahead, if the headlights shine light onto either of the lane markings on both sides of the vehicle, the light from the headlights reflected by the road surface may directly reach an optical sensor, such as a camera, of the preceding vehicle, preventing the optical sensor from fully performing its detection function.

[0030] Therefore, the headlight control device 20 according to the first embodiment controls the light irradiation mode of the headlights 14 using the irradiation mode control unit 242, thereby suppressing the occurrence of glare to occupants of other vehicles and improving the detection function of the optical sensors of other vehicles. Details of the light irradiation mode of the headlights 14 will be described later.

[0031] Next, a hardware configuration of the headlight control device 20 according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the hardware configuration of the headlight control device 20 according to the first embodiment. For example, as shown in Fig. 2, the headlight control device 20 includes a central processing unit (CPU) 20c as a processor, a read-only memory (ROM) 20a, a random access memory (RAM) 20b, and a hard disk drive (HDD) 20d, which are connected to other devices D1 of the vehicle, including an outside vehicle information acquisition unit 11, a vehicle information acquisition unit 12, a map information acquisition unit 13, and headlights 14, via a bus such as a controller area network (CAN). The headlight control device 20 is configured in this manner so that the CPU 20c reads and executes programs stored in the ROM 20a or the HDD 20d, thereby cooperating with the various hardware components to realize various functions. For example, the CPU 20c is configured as a multi-core processor, which is capable of executing multiple processes in parallel. The RAM 20b is used when the CPU 20c executes the programs.

[0032] The HDD 20d is an example of a storage device, and the headlight control device may have a CD (Compact Disc), a DVD (Digital Versatile Disc), a USB (Universal Serial Bus) memory, a flash memory such as an SD card, etc., as a storage device instead of or in addition to the HDD. The headlight control device 20 may also have a processing circuit, which is dedicated hardware, instead of the CPU 20c, the ROM 20a, and the RAM 20b. Such processing circuits may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a system LSI (Large-Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof.

[0033] Next, processing performed by the headlight control device 20 will be described with reference to FIGS. 3 to 6 . FIG. 3 is a flowchart showing processing performed by the headlight control device 20 according to the first embodiment. As shown in FIG. 3 , when processing starts, the headlight control device 20 first acquires information about the road surface condition used to estimate the condition of the road surface on which the host vehicle is in contact (step ST1). In this processing, the headlight control device 20 acquires information for estimating whether the road surface on which the host vehicle is in contact is wet from either or both of the vehicle exterior information acquisition unit 11 and the vehicle information acquisition unit 12 using the road surface condition estimation unit 22. Note that in this processing, the road surface condition estimation unit 22 may be configured to acquire multiple types of information from the vehicle exterior information acquisition unit 11 and the vehicle information acquisition unit 12.

[0034] After performing the process of step ST1, the headlight control device 20 estimates whether the road surface on which the vehicle is in contact is wet (step ST2). In this process, the road surface condition estimation unit 22 may be configured to estimate whether the road surface is wet based on multiple types of information acquired from either or both of the vehicle exterior information acquisition unit 11 and the vehicle information acquisition unit 12. For example, the road surface condition estimation unit 22 may be configured to estimate that the road surface is wet when it detects the operation of the windshield wipers of the vehicle and detects water droplets splashed up from the road surface. This configuration makes it possible for the road surface condition estimation unit 22 to prevent erroneous estimation that the road surface is wet when the object splashed up from the road surface is sand, dust, or other object other than water droplets.

[0035] If the headlight control device 20 estimates in step ST2 that the road surface is wet (YES in step ST2), the headlight control device 20 proceeds to the process for illuminating the lane markings, which will be described below. If the headlight control device 20 estimates in step ST2 that the road surface is not wet (NO in step ST2), the headlight control device 20 returns the process to step ST1 because there is little need to illuminate the lane markings.

[0036] If the processing of step ST2 estimates that the road surface is wet (YES in step ST2), the headlight control device 20 acquires information about the positions of the lane markings (step ST3). In this processing, the lane marking information acquisition unit 21 acquires information about the positions of the lane markings from either or both of the vehicle exterior information acquisition unit 11 and the map information acquisition unit 13. Note that in this processing, the lane marking information acquisition unit 21 may be configured to acquire multiple types of information from the vehicle exterior information acquisition unit 11 and the map information acquisition unit 13.

[0037] After performing the processing of step ST3, the headlight control device 20 sets the direction of light irradiation by the headlights 14 (step ST4). In this processing, the irradiation direction control unit 241 sets the direction of light irradiation by the headlights 14 so that the direction of light for irradiating the lane markings from the headlights 14 is directed toward the lane markings on the road surface near and ahead of the vehicle, based on information regarding the positions of the lane markings acquired by the lane marking information acquisition unit 21. Note that the irradiation direction control unit 241 may be configured to set the direction of light irradiation by the headlights 14 based on multiple types of information regarding the positions of the lane markings acquired by the lane marking information acquisition unit 21.

[0038] After the processing of step ST4, the headlight control device 20 determines whether or not another vehicle has been detected (step ST5). In this processing, the vehicle detection unit 23 determines whether or not another vehicle present ahead of the host vehicle has been detected based on information from the vehicle exterior information acquisition unit 11. In this processing, the vehicle detection unit 23 also estimates the traveling direction of the other vehicle relative to the traveling direction of the host vehicle based on the time change in the position of the other vehicle acquired from one or more of the vehicle exterior information acquisition unit 11, the vehicle information acquisition unit 12, and the map information acquisition unit 13.

[0039] If no other vehicle is detected in step ST5 (NO in step ST5), the headlight control device 20 controls the headlights 14 by the illumination mode control unit 242 to illuminate the road markings in the first mode (step ST6). In this process, the illumination mode control unit 242 controls the headlights 14 to illuminate the road markings with light at a preset brightness based on the illumination direction set by the illumination direction control unit 241.

[0040] 4 is a schematic diagram in a plan view illustrating a state in which the headlight control device 20 according to the first embodiment controls the headlights 14 to irradiate light onto a lane marking in a first manner. For example, as shown in FIG. 4 , when a host vehicle S1 is traveling in a direction A1 ahead on lane R1 of a road R1 with one lane in each direction, which road R1 has lanes R11 and R12, and when lane markings on the road surface of the road R1 include a lane marking L1 that is an outer lane marking for lane R11, a lane marking L2 that is an outer lane marking for lane R12, and a lane marking L3 that is a centerline of the lane between lanes R11 and R12, and when no other vehicle is detected in the processing of step ST5, the headlight control device 20 controls the headlights 14 to irradiate light onto the lane marking L1 in a range H11 and onto the lane marking L3 in a range H21. In addition, if the road on which the vehicle is located has multiple lanes on one side, one or more of the dividing lines L1, L2, and L3 may be lane boundary lines indicating the boundaries between the lanes.

[0041] If another vehicle is detected in the processing of step ST5 (YES in step ST5), the headlight control device 20 controls the headlights 14 via the illumination mode control unit 242 so that the illumination mode of the road markings is a second mode different from the first mode (step ST7). In other words, based on whether or not another vehicle is detected in the processing of step ST5, the headlight control device 20 controls the headlights 14 to switch the illumination mode of the road markings between the first mode and a second mode different from the first mode. In this processing, the illumination mode control unit 242 controls the headlights 14 so that the illumination mode of the road markings is a different mode depending on the movement direction of the detected other vehicle relative to the host vehicle. Note that in the present disclosure, illumination modes of the headlights 14 that are different from the first mode are collectively referred to as the second mode. Therefore, the second mode may include multiple illumination modes different from the first mode.

[0042] 5 is a schematic plan view illustrating a state in which the headlights 14 irradiate the lane marking L3 with light in a second manner when an oncoming vehicle is detected by the headlight control device 20 according to embodiment 1. For example, as shown in FIG. 5 , in the process of step ST5, if the vehicle detection unit 23 detects another vehicle S2 ahead of the host vehicle in lane R12 adjacent to lane R11 and estimates that the traveling direction of the other vehicle S2 with respect to the traveling direction of the host vehicle S1 is opposite direction A1, the illumination mode control unit 242 controls the headlights 14 to irradiate the lane marking L3, which is the lane marking on the side of the other vehicle S2, with light in a second manner different from the first manner.

[0043] Specifically, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2 ahead of the host vehicle S1 in lane R12 adjacent to lane R11 and estimates that the traveling direction of the other vehicle S2 with respect to the traveling direction of the host vehicle S1 is opposite to direction A1, the illumination mode control unit 242 controls the headlights 14 to be in a second mode in which the illumination range of light from the headlights 14 is in range H11 and the lane marking L1 is illuminated, but the lane marking L3 is not illuminated. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects an oncoming vehicle ahead of the host vehicle S1 in lane R12 adjacent to lane R11, the illumination mode control unit 242 controls the headlights 14 to be in a second mode in which the light source of the headlights 14, which is set to direct light toward the lane marking L3, is turned off. As a result, the headlight control device 20 suppresses the reflection of the light from the headlights 14 on the road surface toward oncoming vehicles, thereby reducing the glare caused to the driver of the oncoming vehicle and improving the detection function of the optical sensor of the oncoming vehicle.

[0044] 6 is a schematic plan view illustrating a state in which the headlights 14 irradiate the lane markings with light in the second manner when a preceding vehicle is detected by the headlight control device 20 according to embodiment 1. As shown in FIG. 6 , for example, in the process of step ST5, if the vehicle detection unit 23 detects another vehicle S3 ahead of the host vehicle and estimates that the traveling direction of the other vehicle S3 relative to the traveling direction of the host vehicle S1 is along the direction A1, the headlight control device 20 controls the headlights 14 to irradiate the lane markings L1 on the road surface with light in a range H12 different from the range H11 and to irradiate the lane markings L3 on the road surface with light in a range H22 different from the range H21. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S3 located ahead of the own vehicle and estimates that the direction of travel of the other vehicle S3 relative to the direction of travel of the own vehicle S1 is along direction A1, the headlight control device 20 controls the headlight 14 using the illumination pattern control unit 242 so that the illumination pattern of light on the marking lines L1 and L3, which are the marking lines on both sides of the own vehicle S1, becomes a second pattern different from the first pattern.

[0045] Specifically, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2 ahead of the host vehicle S1 and estimates that the traveling direction of the other vehicle S2 relative to the traveling direction of the host vehicle S1 is along direction A1, the illumination mode control unit 242 controls the headlights 14 so that the illumination range of light on the lane markings L1 and L3 is a second mode different from the first mode. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects a leading vehicle ahead of the host vehicle S1, the illumination mode control unit 242 controls the headlights 14 so that the illumination range of light on the lane markings L1 and L3 is a second mode different from the first mode.

[0046] More specifically, in the processing of step ST5, if the vehicle detection unit 23 detects a preceding vehicle that is ahead of the host vehicle S1, the illumination mode control unit 242 controls the headlights 14 so that the light illumination range for the lane markings L1 and L3 becomes a second mode that is closer to the host vehicle S1 than the first mode. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects a preceding vehicle that is ahead of the host vehicle S1, the illumination mode control unit 242 controls the headlights 14 so that the position of the tip of the light illumination range for the lane markings L1 and L3 becomes a second mode that is closer to the host vehicle S1 than the first mode.

[0047] The illumination mode control unit 242 may be configured to control the headlights 14 so that the distance between the end position of the light illumination range for the demarcation lines L1 and L3 in the first mode and the end position of the light illumination range for the demarcation lines L1 and L3 in the second mode is a predetermined distance. The illumination mode control unit 242 may also be configured to set the distance between the end position of the light illumination range for the demarcation lines L1 and L3 in the first mode and the end position of the light illumination range for the demarcation lines L1 and L3 in the second mode based on either the position of the other vehicle S2 relative to the host vehicle S1 or the speed of the other vehicle S2 relative to the host vehicle S1. For example, the illumination mode control unit 242 may be configured to set the distance between the end position of the light illumination range for the demarcation lines L1 and L3 in the first mode and the end position of the light illumination range for the demarcation lines L1 and L3 in the second mode to be greater the greater the approaching speed of the other vehicle S2 relative to the host vehicle S1.

[0048] Furthermore, the illumination mode control unit 242 may be configured to change the distance between the position of the tip of the light illumination range for the demarcation lines L1 and L3 in the first mode and the position of the tip of the light illumination range for the demarcation lines L1 and L3 in the second mode, based on a change in either the position of the other vehicle S2 relative to the host vehicle S1 or the speed of the other vehicle S2 relative to the host vehicle S1. For example, the illumination mode control unit 242 may be configured to increase the distance between the position of the tip of the light illumination range for the demarcation lines L1 and L3 in the first mode and the position of the tip of the light illumination range for the demarcation lines L1 and L3 in the second mode as the other vehicle S2 approaches the host vehicle S1.

[0049] As a result, the headlight control device 20 suppresses the reflection of light from the headlights 14 on the preceding vehicle by the road surface, thereby suppressing the occurrence of glare for the driver of the oncoming vehicle and improving the detection function of the optical sensor of the preceding vehicle. Note that the phrase "the illumination range is closer to the host vehicle S1 than in the first embodiment" includes all of the following: "the center of the illumination range is closer to the host vehicle S1 than in the first embodiment," "the front end of the illumination range is closer to the host vehicle S1 than in the first embodiment," and "the rear end of the illumination range is closer to the host vehicle S1 than in the first embodiment."

[0050] After performing either the process of step ST6 or the process of step ST7, the headlight control device 20 ends the process. Note that the headlight control device may be configured to return the process to the process of step ST1 after performing either the process of step ST6 or the process of step ST7.

[0051] As described above, the headlight control device 20 according to the first embodiment includes a marking line information acquisition unit 21 that acquires information regarding the position of marking lines on the road surface that the host vehicle is in contact with, a vehicle detection unit 23 that detects other vehicles that are ahead of the host vehicle, and an illumination control unit 24 that, when no other vehicle is detected by the vehicle detection unit 23, controls the headlights 14 of the host vehicle so that the illumination pattern of light onto the marking lines on the road surface is a first pattern, and, when another vehicle is detected by the vehicle detection unit, controls the headlights 14 so that the illumination pattern of light onto the marking lines on the road surface is a second pattern different from the first pattern.

[0052] With this configuration, the headlight control device 20 according to the first embodiment can irradiate the lane markings with light in a manner that corresponds to whether or not another vehicle ahead of the host vehicle has been detected. This makes it possible to irradiate the lane markings with light in a manner that can reduce glare for the occupants of the other vehicle, for example.

[0053] In addition, the headlight control device 20 according to embodiment 1 includes a road surface condition estimation unit that estimates whether the road surface is wet, and the illumination control unit controls the headlights so that the illumination pattern of light onto the road surface dividing lines is a first pattern when the road surface condition estimation unit estimates that the road surface is wet and no moving object is detected by the moving object detection unit, and controls the headlights so that the illumination pattern of light onto the road surface dividing lines is a second pattern different from the first pattern when the road surface condition estimation unit estimates that the road surface is wet and a moving object is detected by the moving object detection unit.

[0054]

[0033] In the first embodiment, the headlight control device 20 emits headlight light onto the lane markings on the road surface based on an estimation that the road surface is wet. This improves the visibility of the lane markings when the road surface is wet during or after rainfall. Furthermore, by suppressing the illumination of light onto the lane markings when the road surface is clean, it is possible to reduce glare on occupants of other vehicles and pedestrians, and to reduce power consumption by the headlights. In the first embodiment, the road surface condition estimation unit 22 estimates whether the road surface is wet based on the intensity of the headlight light reflected from the road surface, and maintains illumination of the headlight light onto the lane markings when the road surface is estimated to be wet. Therefore, when the reflected light is weaker than a threshold, such as when the white lines are deteriorated and faded or when the road surface is heavily soiled, illumination of the headlight light onto the lane markings can be maintained, thereby improving the visibility of the lane markings.

[0055] In the first embodiment, when an oncoming vehicle is detected, the headlight control device 20 controls the headlights 14 to a second mode in which light from the headlights 14 is irradiated onto the lane marking L1 within a range H11 and light is not irradiated onto the lane marking L3. However, the present invention is not limited to this. When an oncoming vehicle is detected, the headlight control device only needs to be able to suppress reflected light of light irradiated from the headlights 14 toward the lane marking, which is irradiated onto at least one of the occupants of the oncoming vehicle and the optical sensor of the oncoming vehicle. For example, when an oncoming vehicle is detected, the headlight control device may be configured to control the headlights 14 to a second mode in which the brightness of the light on the lane marking on the oncoming vehicle's side relative to the host vehicle is smaller than the first mode, or may be configured to control the headlights 14 to a second mode in which the illumination range of light on the lane marking on the oncoming vehicle's side relative to the host vehicle is smaller than the first mode.

[0056] Furthermore, for example, the headlight control device may be configured to control the headlights 14 when an oncoming vehicle is detected so that the brightness of the light on the marking lines on both sides of the vehicle is set to a second mode that is smaller than the first mode, or may be configured to control the headlights 14 so that the illumination range of the light on the marking lines on both sides of the vehicle is set to the second mode that is smaller than the first mode. Note that in the first embodiment, "low brightness" includes a state in which "brightness is zero," and "small range" includes a state in which "range is zero."

[0057] In addition, in the first embodiment, the vehicle detection unit 23 is configured to detect another vehicle ahead of the host vehicle based on information from the vehicle exterior information acquisition unit 11, but is not limited thereto. The vehicle detection unit is configured to detect a moving object ahead of the host vehicle based on information from the vehicle exterior information acquisition unit 11, and the illumination control unit is only required to be able to suppress reflected light of the headlights 14 irradiated onto the moving object when the vehicle detection unit detects the moving object. For example, the vehicle detection unit may be configured to detect a pedestrian as a moving object, or a bicycle and its occupant as a vehicle. The vehicle detection unit may also be configured to acquire information about a moving object ahead of the host vehicle based on information acquired from a server or the like outside the vehicle via a communication network. In the first embodiment, the term "moving object" refers to an animal or an object that can move by force from a driving source, and includes an object that is stationary at the time of detection.

[0058] 3 and 7, a headlight control device according to a second embodiment will be described. The headlight control device according to the second embodiment is different from the headlight control device 20 according to the first embodiment in that the second manner in which the headlights 14 irradiate light onto the road markings when the other vehicle detected by the vehicle detection unit is an oncoming vehicle is different. However, other features are the same, and the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0059] 7 is a schematic plan view illustrating a state in which the headlights 14 irradiate light onto the lane markings in the second manner when an oncoming vehicle is detected by the headlight control device according to embodiment 2. For example, as shown in FIG. 7, in the headlight control device according to embodiment 2, when the vehicle detection unit 23 detects an oncoming vehicle S2 that is ahead of the host vehicle in lane R12 adjacent to lane R11 during the processing of step ST5 shown in FIG. 3, the headlight control device 20 controls the headlights 14 so that light from the headlights 14 is irradiated onto the lane markings L1 on the road surface in a range H11 and onto the lane markings L3 on the road surface in a range H22 that is different from range H21. In other words, in the processing of step ST5, when the vehicle detection unit 23 detects another oncoming vehicle S2 ahead of the vehicle in lane R12 adjacent to lane R11, the headlight control device of embodiment 2 controls the headlight 14 so that the light illumination pattern on the dividing line L3 on the side of the other vehicle S2 becomes a second pattern different from the first pattern.

[0060] Specifically, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in lane R12 adjacent to lane R11, the headlight control device according to the second embodiment controls the headlights 14 so that the light irradiation range for the lane marking L3 is in a second state that is closer to the host vehicle S1 than the first state. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in lane R12 adjacent to lane R11, the headlight control device according to the second embodiment controls the headlights 14 so that the end position of the light irradiation range for the lane marking L3 is in the second state that is closer to the host vehicle S1 than the first state. In this way, the headlight control device according to the second embodiment suppresses reflection of light from the headlights 14 on the oncoming vehicle by the road surface, thereby suppressing glare for the driver of the oncoming vehicle and improving the detection function of the optical sensor of the oncoming vehicle. Generally, when the position of the tip of the light irradiation range for the demarcation line L3 is closer to the host vehicle S1 than in the first mode, the light irradiation range for the demarcation line L3 is smaller than in the first mode.

[0061] 3 and 8, a headlight control device according to a third embodiment will be described. The headlight control device according to the third embodiment is different from the headlight control device 20 according to the first embodiment in that the second manner in which the headlights 14 irradiate light onto the road markings when the other vehicle detected by the vehicle detection unit is an oncoming vehicle is different. However, other features are the same, and the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0062] 8 is a schematic plan view illustrating a state in which the headlights 14 irradiate light onto the lane markings in the second manner when an oncoming vehicle is detected by the headlight control device according to embodiment 3. For example, as shown in FIG. 8, in the headlight control device according to embodiment 3, when the vehicle detection unit 23 detects an oncoming vehicle S2 that is ahead of the host vehicle in lane R12 adjacent to lane R11 during the processing of step ST5 shown in FIG. 3, the headlight control device 20 controls the headlights 14 so that light from the headlights 14 is irradiated onto the lane markings L1 on the road surface in a range H11 and onto the lane markings L3 on the road surface in a range H23 different from the range H21 in the second manner. In other words, in the processing of step ST5, when the vehicle detection unit 23 detects another oncoming vehicle S2 ahead of the vehicle in lane R12 adjacent to lane R11, the headlight control device of embodiment 2 controls the headlight 14 so that the light illumination pattern on the dividing line L3 on the side of the other vehicle S2 becomes a second pattern different from the first pattern.

[0063] Specifically, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the third embodiment controls the headlights 14 so that the light irradiation range for the lane marking L3 is set to a second mode that is smaller than the first mode. For example, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the third embodiment controls the headlights 14 so that the width in the left-right direction of the light irradiation range for the lane marking L3 is set to a second mode that is smaller than the first mode. More specifically, in the processing of step ST5, if the vehicle detection unit 23 detects another oncoming vehicle S2 located ahead of the vehicle S1 in the lane R12 adjacent to the lane R11, the headlight control device of embodiment 3 controls the headlight 14 so that the light irradiation range on the dividing line L3 does not extend beyond the dividing line L3 to the side of the oncoming vehicle.

[0064] Furthermore, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the third embodiment controls the headlights 14 so that the direction of light irradiation to the lane marking L3 becomes a second mode different from the first mode. For example, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the third embodiment controls the headlights 14 so that the direction of light irradiation to the lane marking L3 becomes a second mode that is closer to the lane marking L1 than the first mode. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects an oncoming vehicle S2 that is present ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the third embodiment controls the headlights 14 so that the end of the light irradiation range for the lane marking L3 on the oncoming vehicle side is in a second state that is closer to the lane marking L1 than to the first state. In this way, the headlight control device according to the third embodiment suppresses the light of the headlights 14 that is reflected by the road surface toward the oncoming vehicle, thereby suppressing the occurrence of glare for the driver of the oncoming vehicle and improving the detection function of the optical sensor of the oncoming vehicle.

[0065] 3 and 9, a headlight control device according to a fourth embodiment will be described. The headlight control device according to the fourth embodiment is different from the headlight control device 20 according to the first embodiment in that the second manner in which the headlights 14 irradiate light onto the road markings when the other vehicle detected by the vehicle detection unit is an oncoming vehicle is different. However, other features are the same, and the same components as those in the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

[0066] 9 is a schematic plan view illustrating a state in which the headlights 14 irradiate light onto the lane markings in the second mode when an oncoming vehicle is detected by the headlight control device according to embodiment 4. For example, as shown in FIG. 9, in the headlight control device according to embodiment 4, when the vehicle detection unit 23 detects an oncoming vehicle S2 that is ahead of the host vehicle in lane R12 adjacent to lane R11 during the processing of step ST5 shown in FIG. 3, the headlight control device 20 controls the headlights 14 so that light from the headlights 14 is irradiated onto the lane markings L1 on the road surface in a range H11 and onto the lane markings L3 on the road surface in a range H24 in the second mode. In other words, in the processing of step ST5, when the vehicle detection unit 23 detects another oncoming vehicle S2 ahead of the vehicle in lane R12 adjacent to lane R11, the headlight control device of embodiment 2 controls the headlight 14 so that the light illumination pattern on the dividing line L3 on the side of the other vehicle S2 becomes a second pattern different from the first pattern.

[0067] Specifically, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the fourth embodiment controls the headlights 14 so that the brightness of the light irradiated onto the lane marking L3 becomes a second mode that is lower than the first mode. In other words, in the processing of step ST5, if the vehicle detection unit 23 detects another vehicle S2, an oncoming vehicle, located ahead of the host vehicle S1 in a lane R12 adjacent to the lane R11, the headlight control device according to the fourth embodiment controls the headlights 14 so that the amount of light irradiated onto the lane marking L3 becomes a second mode that is lower than the first mode.

[0068] As a result, the headlight control device according to the fourth embodiment suppresses the reflection of light from the headlights 14 on the road surface toward oncoming vehicles, thereby suppressing the occurrence of glare for the driver of the oncoming vehicle and improving the detection function of the optical sensor of the oncoming vehicle. Note that the range H24 over which the headlight control device according to the fourth embodiment irradiates the lane marking L3 on the road surface with light by the headlights 14 may be the same as the range H21 over which light is irradiated on the lane marking L3 in the first mode, or may be a range different from range H21, for example, a range smaller than range H21.

[0069] 10 to 14, a headlight control device 30 according to a fifth embodiment will be described. The headlight control device 30 according to the fifth embodiment differs from the headlight control device 20 according to the first embodiment in the configuration of the illumination control unit and in the second manner in which the headlights 14 illuminate the road markings with light when the other vehicle detected by the vehicle detection unit is an oncoming vehicle. However, other features are the same, and the same components as those in the first embodiment will be assigned the same reference numerals and will not be described again.

[0070] 10 is a block diagram showing the configuration of a vehicle according to embodiment 5. As shown in FIG. 10 , for example, the vehicle according to embodiment 1 includes an outside-vehicle information acquisition unit 11, a vehicle information acquisition unit 12, a map information acquisition unit 13, headlights 14, and a headlight control device 30. The headlight control device 30 includes a lane marking information acquisition unit 21, a road surface condition estimation unit 22, a vehicle detection unit 23, and an illumination control unit 34. The illumination control unit 34 has an illumination direction control unit 241, an illumination range calculation unit 343, and an illumination mode control unit 342, and controls the headlights 14 based on the information acquired by the lane marking information acquisition unit 21, the road surface condition estimation unit 22, and the vehicle detection unit 23.

[0071] The illumination range calculation unit 343 calculates, based on the position of the other vehicle relative to the host vehicle, the illumination direction and illumination range of the light from the headlights 14 such that the reflected light does not illuminate a specific part of the other vehicle when the light emitted from the headlights 14 is mirror-reflected on the road surface. In other words, based on the distance K1 (see FIG. 13 ) between the host vehicle and the other vehicle, the illumination range calculation unit 343 calculates, based on the distance K1 (see FIG. 13 ) between the host vehicle and the other vehicle, the illumination direction and illumination range of the light from the headlights 14 such that the reflected light does not illuminate a specific part of the other vehicle when the light emitted from the headlights 14 is mirror-reflected on the road surface.

[0072] For example, the specific part may be the position of the face of the driver of the other vehicle, the position of an optical sensor provided in the other vehicle, the position of a rearview mirror of the other vehicle, etc., and may be one of these, a plurality of these, or the entire other vehicle. For example, the illumination range calculation unit 343 estimates the position of the specific part of the other vehicle based on the position of the other vehicle relative to the host vehicle and information on the position of the specific part of the other vehicle corresponding to the position of the other vehicle that is pre-stored in a storage device, and calculates the illumination direction and illumination range of the light of the headlights 14 that does not irradiate the specific part of the other vehicle based on the estimation result. Note that the illumination range calculation unit 343 may be configured to calculate, for each of the multiple light sources of the headlights 14, the illumination direction of light that does not irradiate the specific part of the other vehicle.

[0073] The illumination range calculation unit may also be configured to calculate the position of a specific part of the other vehicle based on information from the vehicle exterior information acquisition unit 11. For example, the illumination range calculation unit may be configured to identify the vehicle model of the other vehicle based on image information from the vehicle exterior information acquisition unit 11, and to calculate the position of a specific part corresponding to the identified vehicle model based on information stored in the storage device. The illumination range calculation unit may also be configured to identify the position of a specific part of the other vehicle by analyzing the image information from the vehicle exterior information acquisition unit 11.

[0074] The illumination mode control unit 342 controls the illumination mode of the headlights 14 based on the information acquired by the vehicle detection unit 23, the illumination direction set by the illumination direction control unit 241, and the calculation results of the illumination range calculation unit 343. Specifically, the illumination mode control unit 342 controls the headlights 14 based on the information acquired by the vehicle detection unit 23, the illumination direction set by the illumination direction control unit 241, and the calculation results of the illumination range calculation unit 343 so that illumination of specific parts of other vehicles with light reflected by the road surface from the headlights 14 is suppressed compared to when light is illuminated in the illumination direction set by the illumination direction control unit 241.

[0075] Fig. 11 is a flowchart showing the processing performed by the headlight control device 30 according to embodiment 5. As shown in Fig. 11, the processing performed by the headlight control device 30 according to embodiment 5 differs from the processing performed by the headlight control device 20 according to embodiment 1 in that, in the processing of step ST5, the processing that follows when another vehicle is detected (YES in step ST5), but the other processing is the same, and steps that are the same as those in embodiment 1 are assigned the same reference numerals and descriptions thereof will be omitted.

[0076] If no other vehicle is detected in step ST5 (NO in step ST5), the headlight control device 30 controls the headlights 14 via the illumination mode control unit 342 to irradiate the road markings with light in a first mode (step ST6). FIG. 12 is a schematic side view illustrating a state in which the headlight control device 30 according to the fifth embodiment irradiates the road markings with light in the first mode. As described above, the processing of step ST6 is similar to the processing of step ST6 performed by the headlight control device 20 according to the first embodiment. In this processing, the headlight control device 30 controls the headlights 14 so that light from the headlights 14 is irradiated in the first mode onto the road markings L3 (see FIG. 4) in a range H21. The light from the headlights 14 irradiated in the range H21 is reflected by the road surface RM1, forming reflected light in a range H21'.

[0077] If another vehicle is detected in the processing of step ST5 (YES in step ST5), the headlight control device 30 calculates, based on the position of the detected other vehicle, the irradiation direction and irradiation range of the light from the headlights 14 so that reflected light is not irradiated onto specific parts of the other vehicle, using the irradiation range calculation unit 343 (step ST8). After processing step ST8, the headlight control device 30 controls the headlights 14 using the irradiation mode control unit 242 based on the calculation result of the irradiation range calculation unit 343 so that the light irradiation mode for the road markings is a second mode different from the first mode (step ST8).

[0078] 13 is a schematic side view illustrating a state in which the headlight 14 is irradiating the lane marking L1 with light in the second mode when an oncoming vehicle is detected by the headlight control device 30 according to the fifth embodiment. For example, after performing the processing of step ST8, the headlight control device 30 controls the headlight 14 by the illumination mode control unit 342 based on the calculation result of the illumination range calculation unit 343 so that the illumination range of the light from the headlight 14 is the second mode in which the lane marking L1 is irradiated in the ranges H25A and H25B. By controlling the headlight 14 in this manner, the headlight control device 30 according to the fifth embodiment irradiates the reflected light in the ranges H25A' and H25B', which is the light from the headlight 14 irradiated in the ranges H25A and H25B, in a manner that avoids the position of the driver D2, which is a specific part of the other vehicle S2, thereby preventing the reflected light from being irradiated on the specific part.

[0079] When the position of the specific part of the other vehicle S2 is the position estimated by the illumination range calculation unit 343, the illumination mode control unit 342 may be configured to control the headlights 14 so that the reflected light is spaced a predetermined distance from the position of the specific part calculated by the illumination range calculation unit 343. Furthermore, the headlight control device 30 may irradiate the light from the headlights 14 to one range or to multiple ranges.

[0080] 14 is a schematic side view illustrating a state in which the headlight 14 is irradiating light onto the lane markings in the second mode when an oncoming vehicle is detected by a headlight control device 30 according to a modification of the fifth embodiment. As shown in FIG. 14 , the headlight control device 30 according to the modification of the fifth embodiment irradiates the reflected light in the ranges H25A′ and H25C′, which is the light from the headlight 14 irradiated in the ranges H25A and H25C, in a manner that avoids the position of the driver D2 and the position of the optical sensor C2 of the other vehicle S2 as specific parts of the other vehicle S2, thereby suppressing the irradiation of the reflected light onto these specific parts. Note that the headlight control device may control the headlight 14 based on the calculation result of the irradiation range calculation unit 343 so that the reflected light is not irradiated onto the specific parts of the other vehicle by avoiding the reflected light in the horizontal direction, or may control the headlight 14 so that the reflected light is not irradiated onto the specific parts of the other vehicle by avoiding the reflected light in the vertical direction.

[0081] After performing either the process of step ST8 or the process of step ST9, the headlight control device 30 ends the process. Note that the headlight control device may be configured to return the process to the process of step ST1 after performing either the process of step ST8 or the process of step ST9.

[0082] In any of the above-described embodiments, the dividing lines on the road surface are not limited to being straight lines, but may be curved or bent.

[0083] In addition, the present disclosure allows for free combination of the respective embodiments, modification of any of the components of the respective embodiments, or omission of any of the components of the respective embodiments.

[0084] An imaging device according to the present disclosure can be used, for example, to control the headlights of a vehicle that irradiate light onto road markings.

[0085] 11 Vehicle exterior information acquisition unit, 12 Vehicle information acquisition unit, 13 Map information acquisition unit, 14 Headlight, 20 Headlight control device, 21 Marking line information acquisition unit, 22 Road surface condition estimation unit, 23 Vehicle detection unit (moving object detection unit), 24 Illumination control unit, 30 Headlight control device, 34 Illumination control unit, 241 Illumination direction control unit, 242 Illumination pattern control unit, 342 Illumination pattern control unit, 343 Illumination range calculation unit, A1 Direction, C2 Optical sensor, D1 Device, D2 Driver, L1 Marking line, L2 Marking line, L3 Marking line, R1 Road, R11 Lane, R12 Lane, RM1 Road surface, S1 Vehicle, S2 Other vehicle (moving object), S3 Other vehicle (moving object).

Claims

1. A headlight control device for a vehicle comprising: a lane marking information acquisition unit that acquires information regarding the position of lane markings on a road surface on which a vehicle is in contact; a moving object detection unit that detects a moving object present ahead of the vehicle; and an illumination control unit that controls the headlights of the vehicle so that the illumination pattern of light onto the lane markings on the road surface becomes a first pattern when the moving object is not detected by the moving object detection unit, and controls the headlights so that the illumination pattern of light onto the lane markings on the road surface becomes a second pattern different from the first pattern when the moving object is detected by the moving object detection unit.

2. A headlight control device for a vehicle as described in claim 1, further comprising a road surface condition estimation unit which estimates whether the road surface is wet or not, wherein the illumination control unit controls the headlights so that the illumination pattern of light onto the marking lines on the road surface becomes the first pattern when the road surface condition estimation unit estimates that the road surface is wet and the moving object detection unit does not detect the moving object, and controls the headlights so that the illumination pattern of light onto the marking lines on the road surface becomes the second pattern different from the first pattern when the road surface condition estimation unit estimates that the road surface is wet and the moving object detection unit detects the moving object.

3. The vehicle headlight control device according to claim 2, characterized in that the illumination control unit controls the headlight so that the direction of illumination of light from the headlight is directed toward a dividing line on the road surface.

4. A headlight control device for a vehicle as described in claim 2 or 3, characterized in that, when the moving object detected by the moving object detection unit is an oncoming vehicle, the illumination control unit controls the headlight so that the illumination pattern of light toward the marking line on the oncoming vehicle's side relative to the vehicle becomes the second pattern different from the first pattern.

5. A headlight control device for a vehicle as described in any one of claims 2 to 4, characterized in that, when the moving object detected by the moving object detection unit is a preceding vehicle, the illumination control unit controls the headlights so that the illumination pattern of light onto the lane markings on both sides of the vehicle becomes the second pattern different from the first pattern.

6. A vehicle headlight control device as described in any one of claims 2 to 5, characterized in that, when the moving object is detected by the moving object detection unit, the illumination control unit controls the headlight so that the light illumination range for the road marking becomes the second mode which is smaller than the first mode.

7. A headlight control device for a vehicle as described in any one of claims 2 to 5, characterized in that, when the moving object is detected by the moving object detection unit, the illumination control unit controls the headlight so that the light illumination range for the road marking becomes the second aspect, which is closer to the vehicle than the first aspect.

8. A vehicle headlight control device as described in any one of claims 2 to 5, characterized in that, when the moving object is detected by the moving object detection unit, the illumination control unit controls the headlight so that the brightness of the light illuminating the road marking becomes the second mode which is lower than the first mode.

9. A vehicle headlight control device as described in any one of claims 2 to 5, characterized in that, when the moving object is detected by the moving object detection unit, the illumination control unit controls the headlight so that illumination of the headlight light reflected by the road surface on a specific part of the moving object detected by the moving object detection unit becomes the second mode which is smaller than the first mode.

10. A vehicle headlight control device as described in any one of claims 2 to 5, characterized in that when the road surface condition estimation unit estimates that the road surface is wet and the moving object detection unit detects the moving object, the illumination control unit controls the headlight to set the illumination range in the second mode based on the distance between the vehicle and the moving object detected by the moving object detection unit.

11. A vehicle headlight control device as described in any one of claims 2 to 10, characterized in that the road surface condition estimation unit estimates whether or not the road surface is wet based on the detection results of a water detection unit that detects water due to rainfall.

12. A vehicle headlight control device as claimed in any one of claims 2 to 11, characterized in that the road surface condition estimation unit estimates whether or not the road surface is wet based on weather-related operations of the vehicle.

13. A vehicle headlight control method performed by an apparatus having a lane marking information acquisition unit, a moving object detection unit, and an illumination control unit, comprising the steps of: the lane marking information acquisition unit acquiring information regarding the position of a lane marking on a road surface on which the vehicle is contacting; the moving object detection unit detecting a moving object present ahead of the vehicle; and the illumination control unit controlling the headlights of the vehicle so that the illumination pattern of light onto the lane marking on the road surface becomes a first pattern when the moving object is not detected by the moving object detection unit, and controlling the headlights so that the illumination pattern of light onto the lane marking on the road surface becomes a second pattern different from the first pattern when the moving object is detected by the moving object detection unit.

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