Headlight control device, headlight control method, and headlight control system

Abstract

This headlight control device (4) is configured so as to comprise a direction detection unit (14) that acquires, from an in-vehicle photographing device (1), a driver image showing the driver of a vehicle and detects the direction in which the driver is facing on the basis of the driver image, and a road type identification unit (15) that acquires, from a sensor (2), host vehicle position information indicating the position of the vehicle and identifies the type of road on which the vehicle is located on the basis of the host vehicle position information. The headlight control device (4) also comprises: an angular range determination unit (16) that, on the basis of the type of road identified by the road type identification unit (15), determines an angular range in which an optical axis angle, which is the angle of the optical axis of a headlight (5) of the vehicle, is allowed to be changed with respect to the traveling direction of the vehicle; and an optical axis angle control unit (17) that controls the angle of the optical axis of the headlight (5) in accordance with the direction detected by the direction detection unit (14) within the angular range determined by the angular range determination unit (16).

Description

[Technical field]

[0001] The present disclosure relates to a headlight control device, a headlight control method, and a headlight control system. [Background technology]

[0002] 2. Description of the Related Art There is a headlight control device that controls the angle of the optical axis of a headlight as the illumination direction of the headlight mounted on a vehicle. As such a headlight control device, Patent Document 1 discloses a control system that includes a lamp control means that detects the direction in which the driver of the vehicle is facing as the direction in which the driver's face is facing, and controls the direction in which the headlights are irradiated in accordance with the direction of the driver's face. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-120148 A Summary of the Invention [Problem to be solved by the invention]

[0004] The control system disclosed in Patent Document 1 had a problem in that even if the direction of the driver's face deviates from the range that needs to be seen in order to drive appropriately according to the surrounding conditions, the lamp control means would control the headlight illumination direction according to the direction of the driver's face.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to obtain a headlight control device that can control the angle of the headlight optical axis according to the direction the driver is facing, while maintaining illumination of the range that needs to be visible in order to drive appropriately according to the surrounding conditions. [Means for solving the problem]

[0006] The headlight control device according to the present disclosure includes a direction detection unit that acquires a driver image, which is an image showing the driver of the vehicle, from an in-vehicle image capture device, and detects the direction in which the driver is facing based on the driver image, and a road type identification unit that acquires vehicle position information indicating the position of the vehicle from a sensor and identifies the type of road on which the vehicle is located based on the vehicle position information. The headlight control device also includes an angle range determination unit that determines an angle range in which a light axis angle, which is the angle of the light axis of the headlight of the vehicle relative to the traveling direction of the vehicle, is allowed to be changed based on the type of road identified by the road type identification unit, and a light axis angle control unit that controls the angle of the light axis of the headlight according to the direction detected by the direction detection unit within the angle range determined by the angle range determination unit. Effect of the Invention

[0007] According to the present disclosure, it is possible to control the angle of the headlight optical axis according to the direction the driver is facing, while maintaining illumination of the range that needs to be seen in order to drive appropriately according to the surrounding conditions. [Brief description of the drawings]

[0008] [Figure 1] 1 is a configuration diagram showing a headlight control system including a headlight control device 4 according to a first embodiment. [Diagram 2] 1 is a hardware configuration diagram showing hardware of a headlight control device 4 according to the first embodiment. [Diagram 3] 1 is a hardware configuration diagram of a computer in the case where the headlight control device 4 is realized by software, firmware, or the like. [Figure 4] FIG. 11 is an explanatory diagram showing the relationship between the type of road and the allowable change angle range. [Diagram 5] 4 is a flowchart showing a headlight control method which is a processing procedure of the headlight control device 4. [Figure 6] FIG. 2 is an explanatory diagram showing an example of a direction in which a driver is facing. [Figure 7]4 is an explanatory diagram showing an example of an allowable change angle range φ of a headlight 5. FIG. [Figure 8] FIG. 8A is an explanatory diagram showing an example in which the direction of the optical axis is controlled to be on the left side of the traveling direction within the allowable angle change range of φ2, and FIG. 8B is an explanatory diagram showing an example in which the direction of the optical axis is controlled to be on the right side of the traveling direction within the allowable angle change range of φ3. [Figure 9] FIG. 11 is a configuration diagram showing a headlight control system including a headlight control device 4 according to a second embodiment. [Figure 10] FIG. 11 is a hardware configuration diagram showing hardware of a headlight control device 4 according to a second embodiment. [Figure 11] FIG. 11 is a configuration diagram showing another headlight control system according to the second embodiment. [Figure 12] FIG. 11 is a configuration diagram showing a headlight control system including a headlight control device 4 according to a third embodiment. [Figure 13] FIG. 11 is a hardware configuration diagram showing hardware of a headlight control device 4 according to a third embodiment. [Figure 14] 1 is an explanatory diagram showing an example of a switching speed V of the optical axis angle α. FIG. [Figure 15] FIG. 15A is an explanatory diagram showing an example in which the switching speed V of the optical axis angle α is changed when the road type is road type (1) or road type (2) and the optical axis angle α of the headlight 5 is an angle close to the boundary of the allowable change angle range φ, and FIG. 15B is an explanatory diagram showing an example in which the road type is road type (3) or road type (4) and the switching speed V of the optical axis angle α is not changed. [Figure 16] FIG. 11 is a configuration diagram showing a headlight control system including a headlight control device 4 according to a fourth embodiment. [Figure 17] FIG. 11 is a hardware configuration diagram showing hardware of a headlight control device 4 according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In order to describe the present disclosure in more detail, embodiments of the present disclosure will be described below with reference to the accompanying drawings.

[0010] Embodiment 1 FIG. 1 is a configuration diagram showing a headlight control system including a headlight control device 4 according to the first embodiment. The headlight control system shown in FIG. 1 includes an in-vehicle photographing device 1, a sensor 2, a map data storage unit 3, a headlight control device 4, and a headlight 5. 1, the in-vehicle photographing device 1, the sensor 2, and the map data storage unit 3 are each provided outside the headlight control device 4. However, this is merely an example, and the in-vehicle photographing device 1, the sensor 2, and the map data storage unit 3 may each be built into the headlight control device 4.

[0011] The interior image capturing device 1 includes a camera for capturing an image of the interior of a vehicle. The camera for capturing an image of the interior of the vehicle may be, for example, an infrared camera, a visible light camera, or an ultraviolet camera. The in-vehicle photographing device 1 photographs the driver of the vehicle and outputs to the headlight control device 4 driver image data indicating a driver image in which the driver is captured. The vehicle is not limited to a four-wheeled automobile, but may be, for example, a motorcycle, a bicycle, a go-kart, an electric wheelchair, an amphibious vehicle, a flying car, or a drone. In the headlight control system shown in FIG. 1, the vehicle is, for example, a flying car, and if the flying car is flying above a certain road, it is considered to be traveling on the certain road.

[0012] The sensor 2 is realized by, for example, a vehicle position acquisition sensor using a Global Navigation Satellite System (GNSS) or a gyro sensor. The sensor 2 detects the position of the vehicle, and outputs to the headlight control device 4 vehicle position information indicating the position of the vehicle.

[0013] The map data storage unit 3 is realized, for example, by a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, an HDD (Hard Disk Drive), an SSD (Solid State Drive), a CD (Compact Disk), a DVD (Digital Versatile Disc), or a Blu-ray Disc (registered trademark). The map data storage unit 3 stores map data including a road map and information indicating the type of road. The types of roads used here are, for example, the types of roads defined by the Road Act. Specific road types include, for example, expressways, general national roads, prefectural roads, and municipal roads. In addition, each of the general national roads and prefectural roads may include, for example, exclusive expressways and general expressways as road types. For example, although farm roads, forest roads, park roads, nature study paths, garden paths, village roads, and private roads are all roads to which the Road Act does not apply, the map data stored in the map data storage unit 3 also includes information indicating the type of farm road, etc. In the headlight control system shown in Fig. 1, the map data storage unit 3 is realized by a RAM or the like. However, this is merely an example, and the map data storage unit 3 may be realized by, for example, a server on a network.

[0014] The headlight control device 4 includes a driver image data acquisition unit 11, a vehicle position information acquisition unit 12, a map data acquisition unit 13, a direction detection unit 14, a road type identification unit 15, an angle range determination unit 16, and a light axis angle control unit 17. The headlight control device 4 is a device that controls the angle of the optical axis of the headlight 5. The angle of the optical axis of the headlight 5 is an angle with respect to the traveling direction of the vehicle. FIG. 2 is a hardware configuration diagram showing the hardware of the headlight control device 4 according to the first embodiment.

[0015] The headlight 5 is a headlamp mounted on a vehicle to illuminate the road ahead of the vehicle. Examples of headlights include halogen lamps, HID (High Intensity Discharged) lamps, LEDs (Light Emitting Diodes), OLEDs (Organic Light Emitting Diodes), LCDs (Liquid Crystal Displays), lasers, blade scans, and DLPs (Digital Light Processing). The headlight 5 may be a headlight for low beam or a headlight for high beam. The headlight 5 may also be a headlight mounted separately for each of the low beam headlight and the high beam headlight. The optical axis of the headlight 5 refers to a virtual light ray that is representative of the luminous flux, which is a bundle of light emitted from the headlight 5. When the headlight 5 is composed of multiple lights, the luminous flux is the sum of the light emitted from each of the multiple lights. Therefore, when the headlight 5 is composed of multiple lights, the optical axis of the headlight 5 refers to a virtual light ray that is representative of the luminous flux. The headlight 5 is mounted on, for example, a beam axis adjuster (not shown). The beam axis adjuster is controlled by the beam axis angle control unit 17 of the headlight control device 4, whereby the angle of the beam axis of the headlight 5 with respect to the traveling direction of the vehicle is controlled. Controlling the angle of the optical axis of the headlight 5 by controlling the optical axis adjuster with the optical axis angle control unit 17 is merely one example. For example, if the headlight 5 is realized by a plurality of LEDs, the optical axis angle control unit 17 may control the angle of the optical axis by switching which of the plurality of LEDs is to be illuminated. For example, in the case where a mirror that switches the direction of light emitted from the headlight 5 is provided, the optical axis angle control unit 17 may control the angle of the optical axis by switching the angle of the mirror.

[0016] The driver image data acquiring unit 11 is realized by, for example, a driver image data acquiring circuit 21 shown in FIG. The driver image data acquisition unit 11 acquires driver image data from the in-vehicle photographing device 1, and outputs the driver image data to the direction detection unit .

[0017] The vehicle position information acquisition unit 12 is realized by, for example, a vehicle position information acquisition circuit 22 shown in FIG. The vehicle position information acquisition unit 12 acquires the vehicle position information from the sensor 2 , and outputs the vehicle position information to the road type identification unit 15 .

[0018] The map data acquisition unit 13 is realized by, for example, a map data acquisition circuit 23 shown in FIG. The map data acquisition unit 13 acquires map data from the map data storage unit 3 , and outputs the map data to the road type identification unit 15 .

[0019] The direction detection unit 14 is realized by, for example, a direction detection circuit 24 shown in FIG. The direction detection unit 14 acquires the driver image data from the driver image data acquisition unit 11 . The direction detection unit 14 detects the direction in which the driver is facing based on the driver image represented by the driver image data. The direction in which the driver is facing may be, for example, the direction of the driver's face or the direction of the driver's line of sight. The face direction of the driver is the direction in which the driver's head is facing. For example, when the driver's torso faces the traveling direction of the vehicle, if the driver's head is tilted by an angle of θ with respect to the traveling direction of the vehicle, the face direction, which is the direction in which the driver is facing, is a direction shifted by the angle θ from the traveling direction of the vehicle. The line of sight of the driver is the direction in which the driver is looking. For example, when the driver's torso faces the traveling direction of the vehicle, if the driver's line of sight is inclined by an angle of θ with respect to the traveling direction of the vehicle, the line of sight direction in which the driver is facing is a direction shifted by the angle θ from the traveling direction of the vehicle. The direction detection unit 14 outputs to the optical axis angle control unit 17 direction data indicating the direction in which the driver is facing.

[0020] The road type identification unit 15 is realized by, for example, a road type identification circuit 25 shown in FIG. The road type identification unit 15 acquires the vehicle position information from the vehicle position information acquisition unit 12 and acquires map data from the map data acquisition unit 13 . The road type identification unit 15 identifies the type of the road on which the vehicle is located based on the vehicle position information and map data. The road type identification unit 15 outputs road type data indicating the type of the road to the angle range determination unit 16.

[0021] The angle range determination unit 16 is realized by, for example, the angle range determination circuit 26 shown in FIG. The angle range determination unit 16 acquires the road type data from the road type identification unit 15 . The angle range determination unit 16 determines an angle range within which the optical axis angle, which is the angle of the optical axis of the headlights 5 of the vehicle relative to the traveling direction of the vehicle, is permitted to be changed, based on the type of road indicated by the road type data. The angle range determination unit 16 outputs angle range data indicating the angle range within which the optical axis angle is permitted to be changed to the optical axis angle control unit 17 .

[0022] The optical axis angle control section 17 is realized by, for example, an optical axis angle control circuit 27 shown in FIG. The optical axis angle control unit 17 obtains the direction data from the direction detection unit 14 and the angle range data from the angle range determination unit 16 . The optical axis angle control unit 17 controls the angle of the optical axis of the headlight 5 in accordance with the direction indicated by the direction data, within the angle range indicated by the angle range data.

[0023] In Fig. 1, it is assumed that each of the components of the headlight control device 4, that is, the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the angle range determination unit 16, and the light axis angle control unit 17, is realized by dedicated hardware as shown in Fig. 2. That is, it is assumed that the headlight control device 4 is realized by the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the angle range determination circuit 26, and the light axis angle control circuit 27. Each of the driver image data acquisition circuit 21, vehicle position information acquisition circuit 22, map data acquisition circuit 23, direction detection circuit 24, road type identification circuit 25, angle range determination circuit 26 and light axis angle control circuit 27 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these.

[0024] The components of the headlight control device 4 are not limited to those realized by dedicated hardware, and the headlight control device 4 may be realized by software, firmware, or a combination of software and firmware. The software or firmware is stored as a program in the memory of a computer. The computer means hardware that executes the program, and includes, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor).

[0025] FIG. 3 is a hardware configuration diagram of a computer in the case where the headlight control device 4 is realized by software, firmware, or the like. When the headlight control device 4 is realized by software, firmware, or the like, a program for causing a computer to execute the respective processing procedures in the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the angle range determination unit 16, and the optical axis angle control unit 17 is stored in the memory 31. Then, the processor 32 of the computer executes the program stored in the memory 31.

[0026] 2 shows an example in which each of the components of the headlight control device 4 is realized by dedicated hardware, and Fig. 3 shows an example in which the headlight control device 4 is realized by software, firmware, etc. However, this is merely one example, and some of the components in the headlight control device 4 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, etc.

[0027] 1 includes a driver image data acquisition unit 11, a vehicle position information acquisition unit 12, and a map data acquisition unit 13 in addition to a direction detection unit 14, a road type identification unit 15, an angle range determination unit 16, and a light axis angle control unit 17. However, this is merely an example, and the direction detection unit 14 may include the driver image data acquisition unit 11, and the road type identification unit 15 may include the vehicle position information acquisition unit 12 and the map data acquisition unit 13.

[0028] For example, the range that needs to be visually recognized in order to drive appropriately according to the surrounding conditions differs between a motor vehicle-only road on which only motor vehicles travel and a road in an urban area on which not only motor vehicles but also pedestrians, motorcycles, etc. travel (hereinafter referred to as a "general road") In particular, on a general road, the driver of a vehicle needs to visually recognize a wide range in order to detect, for example, a pedestrian running out into the road or the presence of an obstacle. An obstacle is an object that exists on the road and may impede the driving of the vehicle. On expressways, there is less need to detect pedestrians jumping out into the road than when driving on general roads, but since there is a higher chance of driving at high speeds, drivers need to avoid distracted driving as much as possible. Therefore, in general, the range in which visibility is required on a motorway is narrower than the range in which visibility is required on an ordinary road.

[0029] 4 is an explanatory diagram showing the relationship between the type of road and the permissible angle change range. The permissible angle change range means the angle range within which the change in the optical axis angle of the headlight 5 is permitted with respect to the traveling direction of the vehicle. FIG. 4 shows an example in which roads are classified into four types. The types of roads belonging to the road type (1) include, for example, expressways in flat areas, and general motorways in flat areas. The types of roads belonging to the road type (2) include, for example, expressways in mountainous areas, and general motorways in mountainous areas. Road types belonging to road type (3) are road types to which the Road Act applies that do not belong to either road type (1) or (2). Specifically, road types belonging to road type (3) include, for example, general national roads, prefectural roads, and municipal roads. General national roads and prefectural roads may each include general motorways as a road type. In the example of FIG. 4, general motorways included in general national roads, etc. are not included in the types of roads belonging to road type (3), but are included in both road type (1) and road type (2). In addition, the types of roads belonging to road type (3) include road types to which the Road Act does not apply. Specifically, the types of roads belonging to road type (3) include, for example, farm roads, forest roads, park roads, nature trails, garden paths, village roads, and private roads. Road types belonging to road type (4) are types that do not belong to any of road types (1), (2), or (3). Specifically, examples of road types belonging to road type (4) include parking lot passages and roads within commercial facilities.

[0030] Roads belonging to road type (3) or road type (4) are passable not only by automobiles but also by people, animals, bicycles, and motorbikes, for example. Roads belonging to road type (3) or road type (4) may have sharp curves as well as intersections, and may be dark with few street lights. When the vehicle is traveling on a road belonging to road type (3) or road type (4), the driver of the vehicle equipped with the headlight control device 4 must thoroughly check for humans, animals, bicycles, or motorcycles jumping out onto the road. In addition, the driver of the vehicle must thoroughly check for the presence of other vehicles, etc. at intersections or sharp curves. Therefore, the driver of a vehicle equipped with the headlight control device 4 needs to check a wide range when the vehicle is traveling on a road belonging to the road type (3) or the road type (4).

[0031] Roads belonging to road type (2) are roads located in mountainous areas, so there is a possibility that animals may run out onto these roads. However, the probability of animals running out onto these roads is smaller than the probability of people or other entities running out onto roads belonging to road type (3). Furthermore, although roads belonging to road type (2) have curves, the radius of curvature of the curves is generally larger than the radius of curvature of curves on roads belonging to road type (3). Furthermore, only automobiles can travel on roads belonging to road type (2). Therefore, a driver of a vehicle equipped with a headlight control device 4 may have a narrower range of confirmation when the vehicle is traveling on a road belonging to road type (2) than when the vehicle is traveling on a road belonging to road type (3). On the other hand, the traveling speed of a vehicle traveling on a road belonging to road type (2) is generally faster than the traveling speed of a vehicle traveling on a road belonging to road type (3). In order to avoid contact with other vehicles, etc., it is more important to avoid distracted driving by the driver when traveling at high speed than distracted driving by the driver when traveling at low speed. Inattentive driving refers to driving with the driver's line of sight significantly deviated from the forward direction of the vehicle. Therefore, when the driver of a vehicle equipped with headlight control device 4 is traveling on a road belonging to road type (2), the driver must drive more carefully and with a smaller awareness of the area than when the driver is traveling on a road belonging to road type (3).

[0032] Roads belonging to road type (1) are roads that are built on flat land, so there is a lower probability of animals jumping out than roads belonging to road type (2). Also, roads belonging to road type (1) are roads that are built on flat land, so there are fewer curves than roads belonging to road type (2). Therefore, a driver of a vehicle equipped with a headlight control device 4 may have a narrower range of confirmation when the vehicle is traveling on a road belonging to road type (1) than when the vehicle is traveling on a road belonging to road type (2).

[0033] For example, if road types are classified into four types as shown in Fig. 4, the permissible change angle ranges when traveling on roads belonging to road types (3) and (4) are the largest among road types (1) to (4). In Fig. 4, the permissible change angle ranges corresponding to roads belonging to road types (3) and (4) are indicated as "large." Next to road type (3), the allowable change angle range is large when traveling on roads belonging to road type (2). In Fig. 4, the allowable change angle range corresponding to roads belonging to road type (2) is indicated as "medium." Among the road types (1) to (4), the permissible change angle range when traveling on a road belonging to road type (1) is the smallest. In Fig. 4, the permissible change angle range corresponding to the road belonging to road type (1) is indicated as "small."

[0034] Next, the operation of the headlight control system shown in FIG. 1 will be described. FIG. 5 is a flowchart showing a headlight control method which is a processing procedure of the headlight control device 4.

[0035] The in-vehicle photographing device 1 photographs the driver of the vehicle and outputs to the headlight control device 4 driver image data indicating a driver image in which the driver is captured. The driver image data acquisition unit 11 of the headlight control device 4 acquires the driver image data from the in-vehicle photographing device 1 (step ST1 in FIG. 5). The driver image data acquisition unit 11 outputs the driver image data to the direction detection unit 14.

[0036] The sensor 2 detects the position of the vehicle, and outputs to the headlight control device 4 vehicle position information indicating the position of the vehicle. The vehicle position information acquisition unit 12 of the headlight control device 4 acquires the vehicle position information from the sensor 2 (step ST2 in FIG. 5). The vehicle position information acquisition unit 12 outputs the vehicle position information to the road type identification unit 15 .

[0037] The map data acquisition unit 13 acquires map data from the map data storage unit 3 (step ST3 in FIG. 5). The map data acquisition unit 13 outputs the map data to the road type identification unit 15. The map data includes information indicating the type of road in addition to the road map.

[0038] The direction detection unit 14 acquires the driver image data from the driver image data acquisition unit 11 . The direction detection unit 14 detects the direction in which the driver is facing, based on the driver image represented by the driver image data (step ST4 in FIG. 5). The direction in which the driver is facing may be, for example, the direction of the driver's face or the direction of the driver's line of sight. The direction of the driver's face is the direction that the driver's head faces. For example, if the driver's torso faces the traveling direction of the vehicle and the driver's head is tilted by an angle of θ with respect to the traveling direction of the vehicle, the direction of the driver's face, which is the direction that the driver faces, is shifted by an angle of θ from the traveling direction of the vehicle, as shown in FIG. 6. The line of sight of the driver is the direction in which the driver is looking. For example, when the driver's torso faces the traveling direction of the vehicle, if the driver's line of sight is inclined by an angle of θ with respect to the traveling direction of the vehicle, the line of sight direction in which the driver is facing is shifted by an angle of θ from the traveling direction of the vehicle, as shown in Fig. 6. FIG. 6 is an explanatory diagram showing an example of the direction in which the driver is facing. The process of detecting the driver's face direction from the driver image is a known technique, and therefore a detailed description thereof will be omitted. Also, the process of detecting the driver's line of sight from the driver image is a known technique, and therefore a detailed description thereof will be omitted. The direction detection unit 14 outputs to the optical axis angle control unit 17 direction data indicating the direction in which the driver is facing.

[0039] The road type identification unit 15 acquires the vehicle position information from the vehicle position information acquisition unit 12 and acquires map data from the map data acquisition unit 13 . The road type identification unit 15 identifies the type RT (Road Type) of the road on which the vehicle is present, based on the vehicle position information and the map data (step ST5 in FIG. 5). Specifically, the road type identification unit 15 checks the road map indicated by the map data against the vehicle position indicated by the vehicle position information to identify the road on which the vehicle is located. Then, the road type identification unit 15 refers to information indicating the type of road contained in the map data, and confirms the type RT of the road on which the vehicle is present. The road type identification unit 15 outputs road type data indicating the road type RT to the angle range determination unit 16.

[0040] In the headlight control device 4 shown in Fig. 1, the road type RT identified by the road type identification unit 15 is any one of road types (1) to (4). However, this is merely an example, and the road type RT identified by the road type identification unit 15 may be a type RT related to a range that needs to be visually recognized in order to drive appropriately. Therefore, the road type RT identified by the road type identification unit 15 may be, for example, a type classified by the speed limit of the road, a type classified by the width of the road, a type classified by the number of lanes of the road, or a type classified by the wetness of the road surface.

[0041] For example, if the road type RT identified by the road type identification unit 15 is a type classified by the speed limit of the road, the road type identification unit 15 may confirm the type RT of the road on which the vehicle is present by referring to information indicating the speed limit of the road contained in the map data. Also, the road type identification unit 15 may acquire an image captured by an on-board camera (not shown) that captures an image of the road ahead of the vehicle, and confirm the type RT of the road on which the vehicle is present by referring to the speed limit of the road indicated by a road sign shown in the captured image. If the road type RT identified by the road type identification unit 15 is, for example, a type classified by the road width, the road type identification unit 15 may, for example, refer to information indicating the road width included in the map data to confirm the road type RT on which the vehicle is present. If the road type RT identified by the road type identification unit 15 is, for example, a type classified by the number of lanes of the road, the road type identification unit 15 may, for example, refer to information indicating the number of lanes of the road contained in the map data to confirm the type RT of the road on which the vehicle is present. If the road type RT identified by the road type identification unit 15 is, for example, a type classified according to the wetness of the road surface, the road type identification unit 15 may, for example, acquire weather information of an area including the road on which the vehicle is present, and confirm whether the road surface of the road is a wet road surface or a dry road surface, thereby confirming the type RT of the road on which the vehicle is present. Also, the road type identification unit 15 may acquire an image captured by an in-vehicle camera (not shown) that captures the front of the vehicle, and confirm whether the road surface shown in the captured image is a wet road surface or a dry road surface, thereby confirming the type RT of the road on which the vehicle is present. Also, the road type identification unit 15 may, based on the sensing result of a rain sensor (not shown), confirm whether the road surface of the road is a wet road surface or a dry road surface, thereby confirming the type RT of the road on which the vehicle is present.

[0042] 1, the road type identification unit 15 checks the type RT of the road on which the vehicle is present by referring to information indicating the type of road contained in the map data. However, this is merely an example, and the road type identification unit 15 may obtain road type data indicating the type RT of the road on which the vehicle is present, for example, by FM (Frequency Modulation) broadcast or a radio beacon, and output the road type data to the angle range determination unit 16.

[0043] The angle range determination unit 16 acquires the road type data from the road type identification unit 15 . The angle range determination unit 16 determines the permissible change angle range φ of the optical axis of the headlights 5 based on the road type RT indicated by the road type data (step ST6 in FIG. 5). The angle range determination unit 16 outputs angle range data indicating the change allowable angle range φ to the optical axis angle control unit 17 .

[0044] Hereinafter, the process of determining the permissible change angle range φ by the angle range determination unit 16 will be specifically described. The angle range determination unit 16 stores, for example, a table as shown in FIG. 4 as a table indicating the relationship between the road type RT and the change allowable angle range φ. The angle range determination unit 16 refers to the table to identify the change allowable angle range φ corresponding to the road type RT. If the road type RT is, for example, road type (1), the angle range determination unit 16 determines the change allowable angle range φ to be "small." If the road type RT is, for example, road type (2), the angle range determination unit 16 determines the change allowable angle range φ to be "medium." If the road type RT is, for example, road type (3) or (4), the angle range determination unit 16 determines the change allowable angle range φ to be "large." The allowable change angle range φ of "small", "medium", and "large" may be default values, or may be changeable by external setting information. Here, three allowable change angle ranges, "small," "medium," and "large," are set as the allowable change angle range φ. However, this is merely an example, and for example, four or more allowable change angle ranges may be set as the allowable change angle range φ.

[0045] FIG. 7 is an explanatory diagram showing an example of the permissible change angle range φ of the headlight 5. As shown in FIG. In FIG. 7, φ1 is the allowable change angle range when the road type RT is road type (1), and φ2 is the allowable change angle range when the road type RT is road type (2). Furthermore, φ3 is the permissible change angle range when the road type RT is the road type (3), and φ4 is the permissible change angle range when the road type RT is the road type (4).

[0046] 1, the angle range determination unit 16 refers to a table to determine the change allowable angle range φ corresponding to the road type RT. However, this is merely an example, and the angle range determination unit 16 may transmit, for example, road type data or vehicle position information to an external server or the like and obtain data indicating the change allowable angle range φ corresponding to the road type RT from the external server or the like.

[0047] 1, the angle range determination unit 16 determines the permissible change angle range φ of the optical axis of the headlight 5 based on the road type RT indicated by the road type data. However, this is merely one example, and when the road type identification unit 15 confirms the type RT of the road on which the vehicle is present by referring to information indicating the speed limit of the road included in the map data, for example, the angle range determination unit 16 may narrow the permissible change angle range φ, for example, as the speed limit of the road becomes faster. When the road type identification unit 15 confirms the type RT of the road on which the vehicle is located, for example, by referring to the number of lanes of the road included in the map data, the angle range determination unit 16 may, for example, widen the change allowable angle range φ as the number of lanes of the road increases.

[0048] The optical axis angle control unit 17 obtains the direction data from the direction detection unit 14 and the angle range data from the angle range determination unit 16 . The optical axis angle control unit 17 controls the angle α of the optical axis of the headlight 5 in accordance with the direction indicated by the direction data, within the change allowable angle range φ indicated by the angle range data (step ST7 in FIG. 5). Specifically, the optical axis angle control unit 17 controls the angle α of the optical axis of the headlight 5 by controlling an optical axis adjuster mounted in the headlight 5, for example.

[0049] The angle α of the optical axis controlled by the optical axis angle control unit 17 will now be described in detail. When the direction in which the driver is facing is shifted by an angle of θ from the vehicle's traveling direction, the optical axis angle control unit 17 compares the absolute value |θ| of the angle θ with φ / 2, which is half the allowable change angle range φ. If the absolute value |θ| of the angle θ is less than or equal to φ / 2 (|θ|≦φ / 2), the direction in which the driver is facing is within the permissible change angle range φ, so the optical axis angle control unit 17 determines the angle θ to be the angle α of the optical axis of the headlight 5, as shown in the following equation (1). α=θ (1) When the absolute value |θ| of the angle θ is greater than φ / 2 (|θ|>φ / 2), the direction in which the driver faces is outside the change allowable angle range φ, so if the angle θ is a positive value, the optical axis angle control unit 17 determines the optical axis angle α to be φ / 2, as shown in the following formula (2). Here, for convenience of explanation, it is assumed that if the driver faces the right side of the vehicle's traveling direction, the angle θ is a positive value. α=φ / 2 (2) When the absolute value |θ| of the angle θ is greater than φ / 2 (|θ|>φ / 2), the direction in which the driver faces is outside the change allowable angle range φ, so if the angle θ is a negative value, the optical axis angle control unit 17 determines the optical axis angle α to be -φ / 2, as shown in the following formula (3). For convenience of explanation, it is assumed here that if the driver faces to the left of the vehicle's traveling direction, the angle θ is a negative value. α=-φ / 2 (3)

[0050] Therefore, if the driver is facing to the left of the vehicle's traveling direction, the direction of the optical axis will be to the left of the vehicle's traveling direction as shown in Fig. 8A. In this case, the direction of the optical axis will be within the change allowable angle range φ regardless of the direction the driver is facing. On the other hand, if the driver is facing to the right of the vehicle, the direction of the optical axis will be to the right of the vehicle as shown in Fig. 8B. In this case, the direction of the optical axis will be within the allowable change angle range φ regardless of the direction the driver is facing. FIG. 8A is an explanatory diagram showing an example in which the direction of the optical axis is controlled to be on the left side of the traveling direction within the allowable change angle range of φ2. FIG. 8B is an explanatory diagram showing an example in which the direction of the optical axis is controlled to the right of the traveling direction within the allowable change angle range of φ3.

[0051] In the headlight control device 4 shown in Fig. 1, when the absolute value |θ| of the angle θ is greater than φ / 2 (|θ|>φ / 2), the optical axis angle control unit 17 determines the angle to be φ / 2 or -φ / 2. However, this is merely an example, and the optical axis angle control unit 17 determines the angle to be, for example, the coefficient k m The angle α of the optical axis of the headlight 5 may be determined using m=1, 2, 3, 4. k m is a coefficient greater than 0 and smaller than 1, and is a coefficient that causes the optical axis angle α to be within the allowable change angle range φ. α = θ × k m (4) 0 <k1<k2<k3<k4<1 (5)

[0052] In the above-described first embodiment, the headlight control device 4 is configured to include a direction detection unit 14 that acquires a driver image, which is an image showing the driver of the vehicle, from the in-vehicle photographing device 1, and detects the direction in which the driver is facing based on the driver image, and a road type identification unit 15 that acquires vehicle position information indicating the position of the vehicle from the sensor 2 and identifies the type of road on which the vehicle is present based on the vehicle position information. The headlight control device 4 also includes an angle range determination unit 16 that determines an angle range in which a change in the optical axis angle, which is the angle of the optical axis of the headlight 5 of the vehicle relative to the traveling direction of the vehicle, is permitted based on the type of road identified by the road type identification unit 15, and an optical axis angle control unit 17 that controls the angle of the optical axis of the headlight 5 according to the direction detected by the direction detection unit 14 within the angle range determined by the angle range determination unit 16. Thus, the headlight control device 4 can maintain illumination of a range that needs to be viewed in order to drive appropriately according to the surrounding situation while controlling the angle of the optical axis of the headlight 5 according to the direction in which the driver is facing.

[0053] In the headlight control device 4 shown in FIG. 1, the angle range determination unit 16 specifies the change allowable angle range φ corresponding to the road type RT every time it acquires road type data from the road type identification unit 15, and outputs the change allowable angle range φ to the light axis angle control unit 17. However, this is merely an example, and the angle range determination unit 16 overwrites and saves the road type RT indicated by the road type data every time it acquires road type data from the road type identification unit 15. Then, the angle range determination unit 16 may specify the change allowable angle range φ corresponding to the road type RT indicated by the latest road type data only when the road type RT indicated by the latest road type data acquired from the road type identification unit 15 is different from the road type RT saved before the overwriting. At this time, the angle range determination unit 16 outputs angle range data indicating the change allowable angle range φ to the light axis angle control unit 17. If the road type RT indicated by the latest road type data acquired from the road type identification unit 15 is the same as the road type RT stored before overwriting, the angle range determination unit 16 does not specify the change allowable angle range φ corresponding to the road type RT indicated by the latest road type data. Therefore, the angle range determination unit 16 does not output the angle range data indicating the change allowable angle range φ to the optical axis angle control unit 17. When the optical axis angle control unit 17 receives the angle range data from the angle range determination unit 16, it controls the angle α of the optical axis of the headlight 5 according to the direction indicated by the direction data, within the allowable change angle range φ indicated by the angle range data.

[0054] Embodiment 2 In the second embodiment, a headlight control device 4 including a road condition determining unit 42 that determines the road conditions ahead of the vehicle based on a forward image that is an image showing the area ahead of the vehicle will be described.

[0055] Fig. 9 is a configuration diagram showing a headlight control system including a headlight control device 4 according to embodiment 2. In Fig. 9, the same reference numerals as in Fig. 1 denote the same or corresponding parts, and therefore description thereof will be omitted. The headlight control system shown in FIG. 9 includes an in-vehicle photographing device 1, a sensor 2, a map data storage unit 3, a headlight control device 4, a headlight 5, and a front camera 6. The front camera 6 is a camera for capturing an image of the area in front of the vehicle. The front camera 6 is, for example, an infrared camera, a visible light camera, or an ultraviolet camera. The front camera 6 captures an image of the area in front of the vehicle, and outputs to the headlight control device 4 front image data indicating a front image that is an image showing the area in front of the vehicle.

[0056] The headlight control device 4 shown in FIG. 9 includes a driver image data acquisition unit 11, a vehicle position information acquisition unit 12, a map data acquisition unit 13, a direction detection unit 14, a road type identification unit 15, a forward image data acquisition unit 41, a road condition determination unit 42, an angle range determination unit 43, and a light axis angle control unit 17. Fig. 10 is a hardware configuration diagram showing the hardware of the headlight control device 4 according to embodiment 2. In Fig. 10, the same reference numerals as in Fig. 2 denote the same or corresponding parts, and therefore description thereof will be omitted.

[0057] The front image data acquisition unit 41 is realized by, for example, a front image data acquisition circuit 51 shown in FIG. The front image data acquisition unit 41 acquires front image data from the front camera 6, and outputs the front image data to the road condition determination unit .

[0058] The road condition determining unit 42 is realized by, for example, a road condition determining circuit 52 shown in FIG. The road condition determination unit 42 acquires the forward image data from the forward image data acquisition unit 41 . The road condition determining unit 42 determines the road conditions ahead of the vehicle based on the forward image represented by the forward image data. Further, the road condition determination unit 42 acquires the vehicle position information from the vehicle position information acquisition unit 12 and acquires map data from the map data acquisition unit 13 . The road condition determining unit 42 determines the road conditions ahead of the vehicle based on the vehicle position information and map data. The road condition determination unit 42 outputs the result of the road condition determination to the angle range determination unit 43 .

[0059] The angle range determination unit 43 is realized by, for example, an angle range determination circuit 53 shown in FIG. The angle range determination unit 43 acquires road type data from the road type identification unit 15, and acquires the judgment result of the road conditions from the road condition judgment unit . The angle range determination unit 43 determines the allowable change angle range φ of the headlights 5 based on the type of road indicated by the road type data and the determined road conditions. The angle range determination unit 43 outputs angle range data indicating the change allowable angle range φ to the optical axis angle control unit 17 .

[0060] In Fig. 9, it is assumed that the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the forward image data acquisition unit 41, the road condition determination unit 42, the angle range determination unit 43, and the light axis angle control unit 17, which are components of the headlight control device 4, are realized by dedicated hardware as shown in Fig. 10. That is, it is assumed that the headlight control device 4 is realized by the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the forward image data acquisition circuit 51, the road condition determination circuit 52, the angle range determination circuit 53, and the light axis angle control circuit 27. Each of the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the forward image data acquisition circuit 51, the road condition judgment circuit 52, the angle range determination circuit 53 and the optical axis angle control circuit 27 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination of these.

[0061] The components of the headlight control device 4 shown in FIG. 9 are not limited to those realized by dedicated hardware, and the headlight control device 4 may be realized by software, firmware, or a combination of software and firmware. When the headlight control device 4 is realized by software, firmware, or the like, a program for causing a computer to execute the respective processing procedures in the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the forward image data acquisition unit 41, the road condition determination unit 42, the angle range determination unit 43, and the optical axis angle control unit 17 is stored in the memory 31 shown in Fig. 3. Then, the processor 32 shown in Fig. 3 executes the program stored in the memory 31.

[0062] 10 shows an example in which each of the components of the headlight control device 4 is realized by dedicated hardware, and Fig. 3 shows an example in which the headlight control device 4 is realized by software, firmware, etc. However, this is merely one example, and some of the components in the headlight control device 4 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, etc.

[0063] 9 includes a driver image data acquisition unit 11, a vehicle position information acquisition unit 12, a map data acquisition unit 13, and a forward image data acquisition unit 41, in addition to a direction detection unit 14, a road type identification unit 15, a road condition determination unit 42, an angle range determination unit 43, and a light axis angle control unit 17. However, this is merely an example, and the direction detection unit 14 may include the driver image data acquisition unit 11, the road type identification unit 15 may include the vehicle position information acquisition unit 12 and the map data acquisition unit 13, and the road condition determination unit 42 may include the forward image data acquisition unit 41.

[0064] Next, the operation of the headlight control device 4 shown in Fig. 9 will be described. Other than the forward image data acquisition unit 41, the road condition determination unit 42, and the angle range determination unit 43, the headlight control device 4 is the same as that shown in Fig. 1. Therefore, here, the operation of the forward image data acquisition unit 41, the road condition determination unit 42, and the angle range determination unit 43 will mainly be described.

[0065] The front camera 6 captures an image in front of the vehicle. The front camera 6 outputs to the front image data acquisition unit 41 front image data indicating a front image which is an image showing the area in front of the vehicle. The front image data acquisition unit 41 acquires front image data from the front camera 6 . The forward image data acquisition unit 41 outputs the forward image data to the road condition determination unit 42.

[0066] The road condition determination unit 42 acquires the forward image data from the forward image data acquisition unit 41 . The road condition determining unit 42 determines the road conditions ahead of the vehicle based on the forward image represented by the forward image data. Further, the road condition determination unit 42 acquires the vehicle position information from the vehicle position information acquisition unit 12 and acquires map data from the map data acquisition unit 13 . The road condition determining unit 42 determines the road conditions ahead of the vehicle based on the vehicle position information and map data. The road condition determination unit 42 outputs the result of the road condition determination to the angle range determination unit 43 .

[0067] The road conditions ahead based on the forward image include, for example, whether the side of the road ahead is covered with an exterior wall, whether an obstacle is present on the road ahead, whether a pedestrian is present on the road ahead, or whether a sidewalk is present on the road ahead. The road conditions ahead based on the forward image are determined, for example, by performing a known image recognition process. Therefore, details of the process of determining the road conditions ahead based on the forward image are omitted. In the headlight control device 4 shown in Fig. 9, the road condition determination unit 42 determines the road conditions ahead of the vehicle based on a forward image. However, this is merely an example, and the road condition determination unit 42 may determine the road conditions ahead of the vehicle using reflected waves received by a radar 7 instead of a forward image captured by the front camera 6, as shown in Fig. 11. Fig. 11 is a configuration diagram showing another headlight control system according to embodiment 2. In Fig. 11, the same reference numerals as in Fig. 9 denote the same or corresponding parts, and therefore description thereof will be omitted. The radar 7, for example, emits radio waves ahead of the vehicle, receives waves of the radio waves reflected by obstacles or the like on the road ahead, and outputs a reception signal of the reflected waves to the headlight control device 4. At this time, the front image data acquisition unit 41 acquires a reception signal of a reflected wave from the radar 7 instead of the front image data, and outputs the reception signal of the reflected wave to the road condition determination unit . The road condition determination unit 42 determines the road conditions ahead of the vehicle using the reflected waves received by the radar 7. The process of determining the road conditions ahead of the vehicle using the reflected waves is a known technique, and therefore a detailed description thereof will be omitted.

[0068] Examples of road conditions ahead based on the vehicle position information and map data include the radius of curvature of the road ahead, and whether or not there is a junction, a branch point, or an intersection on the road ahead. The road condition determination unit 42 can check whether a junction, branch point, or intersection exists at a distance indicated by the set distance data from the vehicle position by comparing the road map indicated by the map data with the vehicle position indicated by the vehicle position information. The set distance data may be stored in an internal memory of the road condition determination unit 42, for example, or may be provided from outside the road condition determination unit 42.

[0069] The angle range determination unit 43 acquires road type data from the road type identification unit 15, and acquires the judgment result of the road conditions from the road condition judgment unit . The angle range determination unit 43 determines the allowable change angle range φ of the headlights 5 based on the road type RT indicated by the road type data and the determined road conditions. The angle range determination unit 43 outputs angle range data indicating the change allowable angle range φ to the optical axis angle control unit 17 .

[0070] Hereinafter, the process of determining the permissible change angle range φ by the angle range determination unit 43 will be specifically described. First, like the angle range determination unit 16 shown in FIG. 1, the angle range determination unit 43 determines the allowable change angle range φ of the headlights 5 based on the road type RT indicated by the road type data. Next, the angle range determination unit 43 corrects the determined change allowable angle range φ based on the result of the determination of the road conditions.

[0071] Specifically, in a situation where the side of the road ahead is covered by an exterior wall, the light emitted from the headlights 5 is blocked by the exterior wall. Even if the headlights 5 emit light to a position blocked by the exterior wall, the range that the driver of the vehicle can see remains almost unchanged. For this reason, the angle range determination unit 43 performs correction to narrow the determined change allowable angle range φ so that the range of light irradiation on the side covered by the exterior wall is reduced. If the side of the road ahead is not covered by an exterior wall, the angle range determination unit 43 does not correct the determined change allowable angle range φ.

[0072] In a situation where there is an obstacle on the road ahead, a pedestrian on the road ahead, or a sidewalk on the road ahead, the driver of the vehicle needs to pay attention to the presence of the obstacle or the pedestrian. Therefore, the angle range determination unit 43 corrects the determined change allowable angle range φ so as to widen it. In addition, if the location of an obstacle, a pedestrian, or a sidewalk is, for example, on the front left side of the vehicle, the angle range determination unit 43 may make a correction so as to widen only the allowable change angle range on the front left side, without widening the allowable change angle range on the front right side. In addition, if the location of an obstacle, a pedestrian, or a sidewalk is, for example, on the front right side of the vehicle, the angle range determination unit 43 may make a correction so as to widen only the allowable change angle range on the front right side, without widening the allowable change angle range on the front left side.

[0073] When the road ahead is curved, the driver of the vehicle needs to check the direction in which the road is curved. The smaller the radius of curvature of the road ahead, the greater the need to check the direction in which the road is curved. For this reason, if the radius of curvature of the road ahead is smaller than a threshold value, the angle range determination unit 43 corrects the determined change allowable angle range φ so as to widen the change allowable angle range on the side where the road is curved. At this time, the angle range determination unit 43 may correct the determined change allowable angle range φ so as to narrow the change allowable angle range on the side where the road is not curved.

[0074] In a situation where a junction, a branch point, or an intersection exists on the road ahead, the driver of the vehicle needs to pay close attention to the presence of other vehicles, etc. at the junction, etc. For this reason, the angle range determination unit 43 corrects the determined change allowable angle range φ so as to widen it. In a situation where there is no junction, branch point, or intersection on the road ahead, the angle range determination unit 43 does not correct the determined change allowable angle range φ.

[0075] In the above-described second embodiment, the headlight control device 4 shown in FIG. 9 is configured to include a road condition determination unit 42 that acquires a forward image, which is an image showing the front of the vehicle, from the front camera 6 and determines the road conditions ahead of the vehicle based on the forward image. In addition, the angle range determination unit 43 of the headlight control device 4 determines the angle range based on the type of road identified by the road type identification unit 15 and the road conditions determined by the road condition determination unit 42. Therefore, like the headlight control device 4 shown in FIG. 1, the headlight control device 4 shown in FIG. 9 can maintain the illumination of the range that needs to be visually recognized to drive appropriately according to the surrounding conditions while controlling the angle of the optical axis of the headlight 5 according to the direction in which the driver is facing, and can control the angle of the optical axis of the headlight according to the road conditions ahead.

[0076] Embodiment 3 In the third embodiment, a headlight control device 4 that changes the switching speed V of the angle α when the optical axis angle control section 44 controls the angle α of the optical axis of the headlight 5 will be described.

[0077] Fig. 12 is a configuration diagram showing a headlight control system including a headlight control device 4 according to embodiment 3. In Fig. 12, the same reference numerals as in Figs. 1, 9 and 11 indicate the same or corresponding parts, and therefore description thereof will be omitted. The headlight control system shown in FIG. 12 includes an in-vehicle photographing device 1, a sensor 2, a map data storage unit 3, a headlight control device 4, and a headlight 5. The headlight control device 4 shown in FIG. 12 includes a driver image data acquisition unit 11, a vehicle position information acquisition unit 12, a map data acquisition unit 13, a direction detection unit 14, a road type identification unit 15, an angle range determination unit 16, and a light axis angle control unit 44. Fig. 13 is a hardware configuration diagram showing the hardware of a headlight control device 4 according to embodiment 3. In Fig. 13, the same reference numerals as in Fig. 2 and Fig. 10 denote the same or corresponding parts, and therefore description thereof will be omitted.

[0078] The optical axis angle control section 44 is realized by, for example, an optical axis angle control circuit 54 shown in FIG. The optical axis angle control unit 44 obtains the direction data from the direction detection unit 14 and the angle range data from the angle range determination unit 16 . The optical axis angle control unit 44 controls the angle α of the optical axis of the headlight 5 in accordance with the direction indicated by the direction data, within the change allowable angle range φ indicated by the angle range data. When controlling the angle α of the optical axis of the headlight 5, the optical axis angle control section 44 changes the switching speed V of the angle α. Specifically, the closer the angle α of the optical axis of the headlight 5 is to the boundary of the permissible change angle range φ, the slower the switching speed V of the angle α of the optical axis is.

[0079] In the headlight control device 4 shown in Fig. 12, the optical axis angle control unit 44 is applied to the headlight control device 4 shown in Fig. 1. However, this is merely an example, and the optical axis angle control unit 44 may be applied to the headlight control device 4 shown in Fig. 9 or the headlight control device 4 shown in Fig. 11.

[0080] In Fig. 12, it is assumed that each of the components of the headlight control device 4, that is, the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the angle range determination unit 16, and the light axis angle control unit 44, is realized by dedicated hardware as shown in Fig. 13. That is, it is assumed that the headlight control device 4 is realized by the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the angle range determination circuit 26, and the light axis angle control circuit 54. Each of the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the angle range determination circuit 26 and the optical axis angle control circuit 54 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination of these.

[0081] The components of the headlight control device 4 are not limited to those realized by dedicated hardware, and the headlight control device 4 may be realized by software, firmware, or a combination of software and firmware. When the headlight control device 4 is realized by software, firmware, or the like, a program for causing a computer to execute the respective processing procedures in the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the angle range determination unit 16, and the optical axis angle control unit 44 is stored in the memory 31 shown in Fig. 3. Then, the processor 32 shown in Fig. 3 executes the program stored in the memory 31.

[0082] 13 shows an example in which each of the components of the headlight control device 4 is realized by dedicated hardware, while Fig. 3 shows an example in which the headlight control device 4 is realized by software, firmware, etc. However, this is merely one example, and some of the components in the headlight control device 4 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, etc.

[0083] Next, the operation of the headlight control device 4 shown in Fig. 12 will be described. Other than the light axis angle control unit 44, the headlight control device 4 is the same as that shown in Fig. 1. Therefore, only the operation of the light axis angle control unit 44 will be described here.

[0084] The optical axis angle control unit 44 obtains the direction data from the direction detection unit 14 and the angle range data from the angle range determination unit 16 . Similar to the optical axis angle control unit 17 shown in FIG. 1, the optical axis angle control unit 44 controls the angle α of the optical axis of the headlight 5 according to the direction indicated by the direction data within the allowable change angle range φ indicated by the angle range data. When controlling the angle α of the optical axis of the headlight 5, the optical axis angle control section 44 changes the switching speed V of the angle α. Specifically, as shown in FIG. 14, the closer the angle α of the optical axis of the headlight 5 is to the boundary of the permissible change angle range φ, the slower the switching speed V of the angle α of the optical axis.

[0085] FIG. 14 is an explanatory diagram showing an example of the switching speed V of the optical axis angle α. In FIG. 14, the horizontal axis represents the angle α of the optical axis of the headlight 5, and the vertical axis represents the switching speed V of the optical axis angle α. 14 shows an example in which the width of the permissible change angle range on the front left side is the same as the width of the permissible change angle range on the front right side. Therefore, the permissible change angle range on the front left side is a range in which the optical axis angle α is from -φ / 2 to 0, and the permissible change angle range on the front right side is a range in which the optical axis angle α is from 0 to φ / 2. When the optical axis angle α is 0, the vehicle belongs to either the permissible change angle range on the front left side or the permissible change angle range on the front right side. In the example of FIG. 14, when the angle α of the optical axis of the headlight 5 is near the center of the allowable change angle range φ, the switching speed V of the headlight 5 is the maximum speed V max When the angle α of the optical axis of the headlight 5 is near the center of the allowable change angle range φ, this means that the angle α of the optical axis currently controlled by the optical axis angle control unit 44 is an angle with a small deviation from the traveling direction of the vehicle. In other words, this means that the angle α of the optical axis currently controlled by the optical axis angle control unit 44 is near 0. In the example of FIG. 14, the closer the optical axis angle α of the headlight 5 is to the boundary of the permissible change angle range φ, the slower the switching speed V of the optical axis angle α becomes. Specifically, the closer the absolute value of the optical axis angle α currently being controlled by the optical axis angle control unit 44 is to φ / 2, the slower the switching speed V of the optical axis angle α becomes.

[0086] In the example of FIG. 14, when the angle α of the optical axis of the headlight 5 is near the center of the allowable change angle range φ, the switching speed V of the headlight 5 is the maximum speed V maxHowever, this is merely one example, and even when the optical axis angle α of the headlight 5 is near the center of the permissible change angle range φ, the switching speed V of the optical axis angle α may be slower as the optical axis angle α is closer to the boundary of the permissible change angle range φ.

[0087] The optical axis angle control unit 44 controls the angle α of the optical axis of the headlight 5 at a switching speed V. If the switching speed V is fast, the tempo at which the angle α of the optical axis of the headlight 5 is switched will be fast. On the other hand, if the switching speed V is slow, the switching tempo of the optical axis angle α of the headlight 5 will be slow. In the example of FIG. 14, when the angle α of the optical axis of the headlight 5 is near the center of the allowable change angle range φ, the switching speed V of the headlight 5 is the maximum speed V max For this reason, when the direction in which the driver is facing is, for example, near the boundary of the permissible change angle range φ, the angle α of the optical axis of the headlight 5 is quickly switched until it approaches the direction in which the driver is facing. On the other hand, the closer the angle α of the optical axis of the headlight 5 is to the boundary of the change allowable angle range φ, the slower the switching speed V of the optical axis angle α. Therefore, the angle α of the optical axis of the headlight 5 switches slowly near the direction in which the driver is facing. As a result, flickering of the headlight 5 caused by the angle α of the optical axis of the headlight 5 switching quickly near the direction in which the driver is facing is prevented. In addition, the switching speed V of the optical axis angle α of the headlight 5 slows near the direction in which the driver is facing, which has the effect of making the driver aware that he is looking in a direction that is largely deviated from the traveling direction of the vehicle, that is, that he is distracted while driving.

[0088] In the above-described third embodiment, the headlight control device 4 shown in Fig. 12 is configured so that the angle switching speed is changed when the optical axis angle control unit 44 controls the angle of the optical axis of the headlight 5. Therefore, like the headlight control device 4 shown in Fig. 1, the headlight control device 4 shown in Fig. 12 can maintain illumination of the range that needs to be viewed in order to drive appropriately according to the surrounding conditions while controlling the angle of the optical axis of the headlight 5 according to the direction in which the driver is facing, and can also enhance the effect of preventing inattentive driving.

[0089] In the headlight control device 4 shown in Fig. 12, the light axis angle control unit 44 changes the switching speed V of the light axis angle α regardless of the road type RT identified by the road type identification unit 15. However, this is merely one example, and if the road type RT identified by the road type identification unit 15 is, for example, road type (1) (2), as shown in Fig. 15A, the light axis angle control unit 44 changes the switching speed V of the angle α when controlling the light axis angle α of the headlight 5. On the other hand, if the type RT is, for example, road type (3) (4), as shown in Fig. 15B, the light axis angle control unit 44 may not change the switching speed V of the angle α when controlling the light axis angle α of the headlight 5. The type RT of the road for which the optical axis angle control unit 44 changes the switching speed V of the optical axis angle α can be changed, for example, by external setting data. Fig. 15A is an explanatory diagram showing an example in which the switching speed V of the optical axis angle α is changed when the road type is road type (1) or road type (2) and the optical axis angle α of the headlight 5 is an angle close to the boundary of the allowable change angle range φ. Fig. 15B is an explanatory diagram showing an example in which the road type is road type (3) or road type (4) and the switching speed V of the optical axis angle α is not changed.

[0090] Embodiment 4 In the fourth embodiment, a headlight control device 4 in which a light axis angle control section 45 changes the switching speed V of the light axis angle α in accordance with the width of the permissible change angle range φ determined by the angle range determination section 16 will be described.

[0091] Fig. 16 is a configuration diagram showing a headlight control system including a headlight control device 4 according to embodiment 4. In Fig. 16, the same reference numerals as in Fig. 1, Fig. 9 and Fig. 11 indicate the same or corresponding parts, and therefore description thereof will be omitted. The headlight control system shown in FIG. 16 includes an in-vehicle photographing device 1, a sensor 2, a map data storage unit 3, a headlight control device 4, and a headlight 5. The headlight control device 4 shown in FIG. 16 includes a driver image data acquisition unit 11, a vehicle position information acquisition unit 12, a map data acquisition unit 13, a direction detection unit 14, a road type identification unit 15, an angle range determination unit 16, and a light axis angle control unit 45. Fig. 17 is a hardware configuration diagram showing the hardware of a headlight control device 4 according to embodiment 4. In Fig. 17, the same reference numerals as in Fig. 2 and Fig. 10 denote the same or corresponding parts, and therefore description thereof will be omitted.

[0092] The optical axis angle control section 45 is realized by, for example, an optical axis angle control circuit 55 shown in FIG. The optical axis angle control unit 45 obtains the direction data from the direction detection unit 14 and the angle range data from the angle range determination unit 16 . The optical axis angle control unit 45 controls the angle α of the optical axis of the headlight 5 according to the direction indicated by the direction data, within the allowable change angle range φ indicated by the angle range data. The optical axis angle control unit 45 changes the switching speed V of the optical axis angle α in accordance with the width of the allowable change angle range φ. Specifically, the optical axis angle control unit 45 reduces the switching speed V of the optical axis angle α as the change allowable angle range φ becomes narrower.

[0093] In the headlight control device 4 shown in Fig. 16, the optical axis angle control unit 45 is applied to the headlight control device 4 shown in Fig. 1. However, this is merely an example, and the optical axis angle control unit 45 may be applied to the headlight control device 4 shown in Fig. 9 or the headlight control device 4 shown in Fig. 11.

[0094] In Fig. 16, it is assumed that each of the components of the headlight control device 4, that is, the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the angle range determination unit 16, and the light axis angle control unit 45, is realized by dedicated hardware as shown in Fig. 17. That is, it is assumed that the headlight control device 4 is realized by the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the angle range determination circuit 26, and the light axis angle control circuit 55. Each of the driver image data acquisition circuit 21, the vehicle position information acquisition circuit 22, the map data acquisition circuit 23, the direction detection circuit 24, the road type identification circuit 25, the angle range determination circuit 26 and the optical axis angle control circuit 55 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination of these.

[0095] The components of the headlight control device 4 are not limited to those realized by dedicated hardware, and the headlight control device 4 may be realized by software, firmware, or a combination of software and firmware. When the headlight control device 4 is realized by software, firmware, or the like, a program for causing a computer to execute the respective processing procedures in the driver image data acquisition unit 11, the vehicle position information acquisition unit 12, the map data acquisition unit 13, the direction detection unit 14, the road type identification unit 15, the angle range determination unit 16, and the optical axis angle control unit 45 is stored in the memory 31 shown in Fig. 3. Then, the processor 32 shown in Fig. 3 executes the program stored in the memory 31.

[0096] 17 shows an example in which each of the components of the headlight control device 4 is realized by dedicated hardware, while Fig. 3 shows an example in which the headlight control device 4 is realized by software, firmware, etc. However, this is merely one example, and some of the components in the headlight control device 4 may be realized by dedicated hardware, and the remaining components may be realized by software, firmware, etc.

[0097] Next, the operation of the headlight control device 4 shown in Fig. 16 will be described. Other than the light axis angle control unit 45, it is the same as the headlight control device 4 shown in Fig. 1. Therefore, only the operation of the light axis angle control unit 45 will be described here.

[0098] The optical axis angle control unit 45 obtains the direction data from the direction detection unit 14 and the angle range data from the angle range determination unit 16 . Similar to the optical axis angle control unit 17 shown in FIG. 1, the optical axis angle control unit 45 controls the angle α of the optical axis of the headlight 5 according to the direction indicated by the direction data within the allowable change angle range φ indicated by the angle range data. When controlling the angle α of the optical axis of the headlight 5, the optical axis angle control section 45 changes the switching speed V of the optical axis angle α in accordance with the width of the allowable change angle range φ. Specifically, the optical axis angle control unit 45 reduces the switching speed V of the optical axis angle α as the change allowable angle range φ becomes narrower.

[0099] For example, if the road type RT is road type (1) and the change allowable angle range φ determined by the angle range determination unit 16 is “small”, the optical axis angle control unit 45 determines the switching speed V of the optical axis angle α to be V1. If the road type RT is, for example, road type (2) and the change allowable angle range φ determined by the angle range determination unit 16 is "medium", the optical axis angle control unit 45 determines the switching speed V of the optical axis angle α to be V2, which is faster than V1. <V2である。 If the road type RT is, for example, road type (3) or (4) and the change allowable angle range φ determined by the angle range determination unit 16 is "large", the optical axis angle control unit 45 determines the switching speed V of the optical axis angle α to be V3, which is faster than V2. <V3である。

[0100] The optical axis angle control unit 45 controls the angle α of the optical axis of the headlight 5 at the determined switching speed V. If the determined switching speed V is fast, the switching tempo of the optical axis angle α will be fast. On the other hand, if the determined switching speed V is slow, the switching tempo of the optical axis angle α will be slow. If the switching tempo of the optical axis angle α is fast, the optical axis angle α of the headlight 5 will be switched quickly. On the other hand, if the switching tempo of the optical axis angle α is slow, flickering of the headlights 5 is prevented.

[0101] In the above-described fourth embodiment, the headlight control device 4 shown in Fig. 16 is configured so that the optical axis angle control unit 45 changes the switching speed of the angle of the optical axis of the headlight 5 according to the width of the angle range determined by the angle range determination unit 16. Therefore, like the headlight control device 4 shown in Fig. 1, the headlight control device 4 shown in Fig. 16 can maintain illumination of the range that needs to be visible for appropriate driving according to the surrounding conditions while controlling the angle of the optical axis of the headlight 5 according to the direction in which the driver is facing, and can quickly switch the optical axis angle according to the change allowable angle range φ or prevent flickering of the headlight 5.

[0102] In addition, the present disclosure allows free combination of the respective embodiments, modification of any of the components of each embodiment, or omission of any of the components of each embodiment. [Industrial Applicability]

[0103] The present disclosure is suitable for a headlight control device, a headlight control method, and a headlight control system. [Explanation of symbols]

[0104] 1 in-vehicle photographing device, 2 sensor, 3 map data storage unit, 4 headlight control device, 5 headlight, 6 front camera, 7 radar, 11 driver image data acquisition unit, 12 vehicle position information acquisition unit, 13 map data acquisition unit, 14 direction detection unit, 15 road type identification unit, 16 angle range determination unit, 17 light axis angle control unit, 21 driver image data acquisition circuit, 22 vehicle position information acquisition circuit, 23 map data acquisition circuit, 24 direction detection circuit, 25 road type identification circuit, 26 angle range determination circuit, 27 light axis angle control circuit, 31 memory, 32 processor, 41 forward image data acquisition unit, 42 road condition determination unit, 43 angle range determination unit, 44 light axis angle control unit, 45 light axis angle control unit, 51 forward image data acquisition circuit, 52 road condition determination circuit, 53 angle range determination circuit, 54 light axis angle control circuit, 55 light axis angle control circuit.

Claims

1. a direction detection unit that acquires a driver image, which is an image showing a driver of the vehicle, from an in-vehicle photographing device, and detects a direction in which the driver is facing based on the driver image; a road type identification unit that acquires vehicle position information indicating a position of the vehicle from a sensor, and identifies a type of a road on which the vehicle is present based on the vehicle position information; an angle range determination unit that determines an angle range in which a light axis angle, which is an angle of a light axis of a headlight of the vehicle with respect to a traveling direction of the vehicle, is allowed to be changed based on the type of road identified by the road type identification unit; a light axis angle control unit that controls an angle of the light axis of the headlight in accordance with the direction detected by the direction detection unit within the angle range determined by the angle range determination unit; A headlight control device comprising:

2. The road type identification unit 2. The headlight control device according to claim 1, wherein the type of the road on which the vehicle is located is identified by collating the vehicle position indicated by the vehicle position information with map data.

3. The direction detection unit is 2. The headlight control device according to claim 1, wherein the direction in which the driver is facing is detected as a direction of a face of the driver.

4. The direction detection unit is 2. The headlight control device according to claim 1, wherein the direction in which the driver is facing is detected as the line of sight of the driver.

5. a road condition determination unit that obtains a front image, which is an image showing the front of the vehicle, from a front camera, and determines a road condition ahead of the vehicle based on the front image; The angle range determination unit 2. The headlight control device according to claim 1, wherein the angle range is determined based on the type of road identified by the road type identification unit and the road conditions determined by the road conditions determination unit.

6. The road condition determination unit 6. The headlight control device according to claim 5, wherein the road conditions ahead of the vehicle are determined based on the vehicle position information and map data in addition to the forward image.

7. The optical axis angle control unit is 2. The headlight control device according to claim 1, wherein a speed at which the angle of the optical axis of the headlight is changed is changed while the angle of the optical axis of the headlight is being controlled.

8. The optical axis angle control unit is 8. The headlight control device according to claim 7, wherein the speed of switching the angle of the optical axis of the headlight is slowed down as the angle of the optical axis of the headlight is closer to the boundary of the angle range determined by the angle range determination unit.

9. The optical axis angle control unit is 2. The headlight control device according to claim 1, wherein a speed at which the angle of the optical axis of the headlight is changed is changed in accordance with the width of the angle range determined by the angle range determination unit.

10. The optical axis angle control unit is 10. The headlight control device according to claim 9, wherein the speed of switching the angle of the optical axis is made slower as the angle range determined by the angle range determination unit becomes narrower.

11. A direction detection unit acquires a driver image, which is an image showing a driver of the vehicle, from an in-vehicle photographing device, and detects a direction in which the driver is facing based on the driver image; a road type identification unit that acquires vehicle position information indicating a position of the vehicle from a sensor, and identifies a type of a road on which the vehicle is present based on the vehicle position information; an angle range determination unit determines an angle range in which a change in an optical axis angle, which is an angle of an optical axis of a headlight of the vehicle with respect to a traveling direction of the vehicle, is permitted based on the type of road identified by the road type identification unit; A light axis angle control unit controls the angle of the light axis of the headlight within the angle range determined by the angle range determination unit in accordance with the direction detected by the direction detection unit. Headlight control method.

12. an in-vehicle photographing device for photographing a driver of the vehicle; a direction detection unit that acquires a driver image, which is an image showing the driver, from the in-vehicle photographing device, and detects a direction in which the driver is facing based on the driver image; a road type identification unit that acquires vehicle position information indicating a position of the vehicle from a sensor, and identifies a type of a road on which the vehicle is present based on the vehicle position information; an angle range determination unit that determines an angle range in which a light axis angle, which is an angle of a light axis of a headlight of the vehicle with respect to a traveling direction of the vehicle, is allowed to be changed based on the type of road identified by the road type identification unit; a light axis angle control unit that controls an angle of the light axis of the headlight in accordance with the direction detected by the direction detection unit within the angle range determined by the angle range determination unit; Headlight control system with

Images