Driver assistance system and driver assistance procedures

Abstract

The purpose of the present invention is to provide a technology capable of appropriately controlling a light device that irradiates a road from a vehicle. An acquisition unit acquires location information for the vehicle, travel lane information indicating the travel lane in which the vehicle is traveling, and road information. When the control unit has determined, on the basis of the location information, the travel lane information, and the road information, that there is a branch road directly connected to the travel lane and the vehicle is traveling in a first irradiation section satisfying a predetermined locational relationship with regard to the branching point of the travel lane and the branch road, the control unit controls the light device to cause the same to irradiate the branch road according to a first irradiation mode.

Description

Driving assistance device and driving assistance method

[0001] The present disclosure relates to a driving assistance device and a driving assistance method.

[0002] A technology has been proposed that swivels the headlights to direct the headlights toward the branch road when the lane in which the vehicle is traveling is connected to the branch road, but does not perform this control when the lane in which the vehicle is traveling is not connected to the branch road (see, for example, Patent Document 1). This technology allows the driver to easily recognize the existence of a branch road.

[0003] JP 2010-105580 A

[0004] In the above technology, in order for the vehicle to swivel so as to illuminate the branching road at a point far from the branching point, the swivel angle must be small. However, if the swivel angle is small, the driver may not notice the swivel of the headlights and may not be able to recognize the existence of the branching road. In addition, if the swivel angle is small, the driver may not be able to understand the shape of the branching road because the part of the branching road further back from the branching point cannot be illuminated.

[0005] On the other hand, in order to swivel the vehicle so that a wide area of ​​the branching road is illuminated when the vehicle is close to the branching point, it is necessary to increase the swivel angle. However, if the swivel angle is increased, the headlights may be able to illuminate the branching road but may not be able to illuminate the road ahead of the vehicle.

[0006] Therefore, the present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that can appropriately control lighting devices that illuminate a road from a vehicle.

[0007] The driving assistance device according to the present disclosure is a driving assistance device that controls lighting devices that illuminate a road from a vehicle, and includes an acquisition unit that acquires vehicle position information, driving lane information indicating the driving lane in which the vehicle is traveling, and road information, and a control unit that controls the lighting devices to illuminate the branch road in a first illumination mode when it is determined, based on the position information, driving lane information, and road information, that there is a branch road that is directly connected to the driving lane and that the vehicle is traveling in a first illumination section that satisfies a predetermined positional relationship with respect to the branch point between the driving lane and the branch road.

[0008] According to the present disclosure, when it is determined that there is a branch road directly connected to the driving lane and that the vehicle is traveling in the first illumination section, the lighting device is controlled to illuminate the branch road in the first illumination mode. With this configuration, it is possible to appropriately control the lighting device that illuminates the road from the vehicle.

[0009] The objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0010] 1 is a block diagram showing a configuration of a driving assistance device according to Embodiment 1. FIG. 2 is a block diagram showing a configuration of a driving assistance device according to Embodiment 2. FIG. 3 is a flowchart showing the operation of the driving assistance device according to Embodiment 2. FIG. 4 is a diagram for explaining the operation of the driving assistance device according to Embodiment 2. FIG. 5 is a diagram for explaining the operation of the driving assistance device according to Embodiment 2. FIG. 6 is a diagram for explaining the operation of the driving assistance device according to Modification 3 of Embodiment 2. FIG. 7 is a diagram for explaining the operation of the driving assistance device according to Modification 3 of Embodiment 2. FIG. 8 is a diagram for explaining the operation of the driving assistance device according to Modification 3 of Embodiment 2. FIG. 9 is a diagram for explaining the operation of the driving assistance device according to Modification 3 of Embodiment 2. FIG. 10 is a diagram for explaining the operation of the driving assistance device according to Modification 6 of Embodiment 2. FIG. 11 is a diagram for explaining the operation of the driving assistance device according to Modification 6 of Embodiment 2. FIG. 12 is a block diagram showing a configuration of a driving assistance device according to Modification 2 of Embodiment 3. FIG. 13 is a flowchart showing the operation of the driving assistance device according to Embodiment 4. FIG. 14 is a diagram for explaining the operation of the driving assistance device according to Modification 1 of Embodiment 4. FIG. 1 is a diagram for explaining the operation of a driving assistance device according to a first modification of embodiment 4. FIG. 2 is a diagram for explaining the operation of a driving assistance device according to a fifth embodiment. FIG. 3 is a flowchart showing the operation of a driving assistance device according to the fifth embodiment. FIG. 4 is a diagram for explaining the operation of a driving assistance device according to a fourth modification of embodiment 5. FIG. 5 is a diagram for explaining the operation of a driving assistance device according to a seventh modification of embodiment 5. FIG. 6 is a diagram for explaining the operation of a driving assistance device according to a seventh modification of embodiment 5. FIG. 7 is a diagram for explaining the operation of a driving assistance device according to an eighth modification of embodiment 5. FIG. 8 is a diagram for explaining the operation of a driving assistance device according to an eighth modification of embodiment 5. FIG. 9 is a block diagram showing the hardware configuration of a driving assistance device according to another modification. FIG. 10 is a block diagram showing the hardware configuration of a driving assistance device according to another modification. FIG. 11 is a block diagram showing the configuration of a server according to another modification.FIG. 10 is a block diagram showing the configuration of a communication terminal according to another modified example.

[0011] <First Embodiment> Fig. 1 is a block diagram showing the configuration of a driving assistance device 1 according to the first embodiment. The driving assistance device 1 of Fig. 1 includes an acquisition unit 11 and a control unit 12, and controls lighting devices 3 that illuminate a road from a vehicle. The lighting devices 3 may include headlights of the vehicle, sublights of the vehicle, or both. Note that the sublights are secondary lighting devices that provide auxiliary illumination, such as parking lamps and fog lamps. The road may include only one lane, or multiple lanes.

[0012] The acquisition unit 11 acquires vehicle position information. For this function of the acquisition unit 11, a device that detects vehicle position information based on signals from satellites such as a GPS (Global Positioning System) may be used, or an image processing device that recognizes vehicle position information based on images of the vehicle's surroundings may be used, or an interface with these devices may be used.

[0013] The acquisition unit 11 acquires driving lane information indicating the driving lane that the vehicle is traveling in. For this function of the acquisition unit 11, for example, a high-precision locator device using a high-precision map may be used, or an image processing device that recognizes vehicle position information based on an image of the vehicle's surroundings may be used, or an interface with these devices may be used.

[0014] The acquisition unit 11 acquires road information. The road information includes information indicating the connection relationships between roads. The function of the acquisition unit 11 to acquire road information may use an interface that acquires road information from a storage device of the vehicle, or may use a communication device that receives road information from a server external to the vehicle, or may use an interface of the communication device. Based on the position information, driving lane information, and road information acquired by the acquisition unit 11, the control unit 12 determines whether there is a branch road directly connected to the driving lane and whether the vehicle is traveling in the first illumination section. An example of this determination will be described below.

[0015] First, the control unit 12 determines, based on the driving lane information and road information, whether there is a branch road directly connected to the driving lane the vehicle is traveling in. A branch road directly connected to the driving lane is a branch road that does not have any other lanes between it and the driving lane.

[0016] If it is determined that a branch road directly connected to the traveling lane exists, the control unit 12 determines whether the vehicle is traveling in a first illumination section based on the branch road and the position information. The first illumination section is a section that satisfies a predetermined positional relationship with respect to the branch point between the traveling lane and the branch road. The predetermined positional relationship may be, for example, a road between the branch point and a point that is a predetermined distance away from the branch point toward the vehicle, or may be any other positional relationship.

[0017] If the above judgment result determines that there is a branch road directly connected to the driving lane and that the vehicle is traveling in the first illumination section, the control unit 12 controls the lighting device 3 to illuminate the branch road in the first illumination mode.

[0018] Summary of First Embodiment According to the driving assistance device 1 of the first embodiment described above, when it is determined that there is a branch road directly connected to the traveling lane and that the vehicle is traveling in a first illumination section, control is performed to cause the lighting devices 3 to illuminate the branch road in the first illumination mode. This configuration makes it possible to control the lighting devices 3 to illuminate the branch road in a section where the vehicle is an appropriate distance away from the branch point, thereby allowing an appropriate swivel angle to be used for the lighting devices 3. As a result, it is possible to achieve an appropriate balance between illuminating the traveling lane ahead of the vehicle and illuminating a wide area of ​​the branch road, thereby enabling appropriate control of the lighting devices 3.

[0019] 2 is a block diagram showing the configuration of a driving assistance device 1 according to a second embodiment. In the following, among the components according to the second embodiment, components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components will be mainly described.

[0020] 2 is included in a vehicle system 4. The vehicle system 4 includes not only the driving assistance device 1, but also a high-accuracy locator device 2 and a lighting device 3.

[0021] The high-precision locator device 2 includes a high-precision map database (DB) 21 and a high-precision positioning unit 22. The high-precision map DB 21 stores road information on a lane-by-lane basis. The road information may include not only the connection relationships between roads and lanes, but also the planar shapes, gradients, and types of roads and lanes, and may also include angles formed between lanes and roads at their connection points. The high-precision positioning unit 22 detects vehicle position information on a lane-by-lane basis and vehicle driving lane information on a lane-by-lane basis based on the road information stored in the high-precision map DB 21 and signals from artificial satellites such as GPS.

[0022] The lighting device 3 is similar to the lighting device 3 described in the first embodiment, and includes a headlight 31 and a sublight 32. In the second embodiment, the sublight 32 is capable of freely changing the direction and width of its illumination range. The direction and width of the illumination range of the sublight 32 can be controlled, for example, by controlling the illumination direction of the light source of the sublight 32 relative to the reflector of the sublight 32. The sublight 32 may also be capable of illuminating the road with at least one of letters, figures, and symbols.

[0023] The driving assistance device 1 includes a road information acquisition unit 11 a, a vehicle position acquisition unit 11 b, and an illumination control unit 12 a. The road information acquisition unit 11 a and the vehicle position acquisition unit 11 b are included in the concept of the acquisition unit 11 in Fig. 1, and the illumination control unit 12 a is included in the concept of the control unit 12 in Fig. 1.

[0024] The road information acquisition unit 11a acquires road information from the high-precision map DB 21 of the high-precision locator device 2. The vehicle position acquisition unit 11b acquires position information and driving lane information from the high-precision positioning unit 22 of the high-precision locator device 2.

[0025] The illumination control unit 12a has the same functions as the control unit 12 in Embodiment 1. Based on the position information and driving lane information acquired by the vehicle position acquisition unit 11b and the road information acquired by the road information acquisition unit 11a, the illumination control unit 12a determines whether there is a branch road directly connected to the driving lane and whether the vehicle is traveling in the first illumination section.

[0026] The first illumination section is, for example, a driving lane between a junction point between the driving lane and a branch road and a point a predetermined distance (e.g., 100 m) away from the junction point toward the vehicle. The first illumination section may be changed depending on the shape of the driving lane, the shape of the branch road, the vehicle's traveling speed, and the like. For example, when the road curvature of the driving lane is large, it is difficult to see ahead of the vehicle, so the first illumination section may be changed so that the predetermined distance of the first illumination section is greater than 100 m. Furthermore, for example, the first illumination section may be changed so that the predetermined distance of the first illumination section increases as the vehicle's traveling speed increases, i.e., so that illumination in the first illumination mode is performed at an earlier stage.

[0027] If the above judgment result indicates that there is a branch road directly connected to the driving lane and that the vehicle is traveling in the first illumination section, the illumination control unit 12a controls the sub-light 32 to illuminate the branch road in the first illumination mode.

[0028] <Operation> Fig. 3 is a flowchart showing the operation of the driving assistance device 1 according to the embodiment 2. The operation in Fig. 3 is performed whenever the vehicle is traveling.

[0029] First, in step S1, the illumination control unit 12a determines whether the headlights 31 are turned on and illuminating. The illumination of the headlights 31 may be a high beam that illuminates a road, for example, 100 m ahead of the vehicle, or a low beam that illuminates a road, for example, 40 m ahead of the vehicle. In the following, the illumination of the headlights 31 will be described as a high beam. If it is determined that the headlights 31 are illuminating, the process proceeds to step S2. If it is not determined that the headlights 31 are illuminating, the process of step S1 is performed again.

[0030] In step S2, the vehicle position acquisition unit 11b acquires the position information and the driving lane information from the high-accuracy positioning unit 22 of the high-accuracy locator device 2.

[0031] In step S3, the road information acquisition unit 11a acquires road information from the high precision map DB 21 of the high precision locator device 2. Note that the road information acquisition unit 11a may acquire only road information around the vehicle from the high precision map DB 21.

[0032] In step S4, the illumination control unit 12a determines whether or not there is a branch road directly connected to the driving lane based on the driving lane information and road information. If it is determined that there is a branch road, the process proceeds to step S5, and if it is not determined that there is a branch road, the process proceeds to step S7.

[0033] In step S5, the illumination control unit 12a determines whether the vehicle is traveling in the first illumination section based on the branch road determined in step S4 and the position information. If it is determined that the vehicle is traveling in the first illumination section, the process proceeds to step S6. If it is not determined that the vehicle is traveling in the first illumination section, the process proceeds to step S7.

[0034] In step S6, the illumination control unit 12a turns on the sub-light 32 and controls the sub-light 32 to illuminate the branching road in the first illumination mode. The illumination of the headlight 31 is maintained unless the driver performs an operation to turn off the headlight 31. Then, the process proceeds to step S8.

[0035] In step S7, the illumination control unit 12a stops illumination by the sublight 32 in the first illumination mode. Illumination by the headlight 31 is maintained unless the driver performs an operation to turn off the headlight 31. Then, the process proceeds to step S8.

[0036] In step S8, the illumination control unit 12a determines whether or not the headlights 31 are turned off. If it is determined that the headlights 31 are turned off, the operation in Fig. 3 ends, and if it is not determined that the headlights 31 are turned off, the process returns to step S2.

[0037] 4 to 6 are diagrams illustrating the operation of the driving assistance device 1 according to the second embodiment. The road 52 includes a left lane 52a and a right lane 52b. The left lane 52a is directly connected to a branch road 53. On the other hand, the right lane 52b is not directly connected to the branch road 53, but is indirectly connected to the branch road 53.

[0038] 4 and 5 , the vehicle 51 is traveling in a left lane 52a directly connected to a branch road 53, and the vehicle 51 is traveling within 100 meters of a junction Q1 between the left lane 52a and the branch road 53, i.e., in the first illumination section. In this case, the processes of steps S4, S5, and S6 in FIG. 3 are performed, so that the headlights 31 illuminate an illumination range 31a including the traveling lane ahead of the vehicle 51, and the sub-lights 32 illuminate an illumination range 32a including a point Q2 on the branch road 53. The point Q2 is a point a predetermined distance (e.g., 10 meters) away from the junction Q1. The illumination control unit 12a according to the second embodiment controls the first illumination mode of the sub-lights 32 based on the planar shape of the branch road 53 included in the road information so that the point Q2 is included in the illumination range 32a.

[0039] The illumination control unit 12a may control the first illumination mode of the sublight 32 based on the distance between the position of the vehicle 51 and the junction Q1. For example, as shown in FIGS. 4 and 5 , the illumination control unit 12a may control the direction of the illumination range 32a of the sublight 32 so that the illumination range 32a of the sublight 32 approaches the left side of the vehicle 51 as the distance between the position of the vehicle 51 and the junction Q1 decreases. The illumination control unit 12a may also control the width of the illumination range 32a of the sublight 32 so that the width of the illumination range 32a of the sublight 32 increases as the distance between the position of the vehicle 51 and the junction Q1 decreases. The illumination control unit 12a may also control the illumination of the sublight 32 so that the time interval for controlling the illumination range 32a of the sublight 32 decreases as the distance between the position of the vehicle 51 and the junction Q1 decreases.

[0040] When the vehicle 51 passes the branch point Q1, the vehicle 51 stops traveling in the first illumination section, and the processing of steps S4, S5, and S7 in Figure 3 is performed, so that the headlight 31 illuminates the illumination range 31a but the sublight 32 does not illuminate.

[0041] In Fig. 6, the branch road 53 has a left lane 52a, which is not the driving lane, between it and the right lane 52b, which is the driving lane of the vehicle 51, and is indirectly connected to the driving lane. In this case, the processing of steps S4 and S7 in Fig. 3 is performed, so that the headlights 31 illuminate the illumination range 31a but the sub-lights 32 do not illuminate. Note that if the vehicle 51 changes lanes from the right lane 52b to the left lane 52a from the state in Fig. 6, the processing of steps S4, S5, and S6 in Fig. 3 is performed, so that the headlights 31 illuminate the illumination range 31a and the sub-lights 32 illuminate the illumination range 32a.

[0042] The above description has been given taking as an example a case where the road 52 includes two lanes (the left lane 52a and the right lane 52b) and the left lane 52a is directly connected to a branch road. Even if the road includes three or more lanes or the right lane is directly connected to a branch road, as in the above example, if the lane in which the vehicle 51 is traveling is directly connected to the branch road, the sub-light 32 will illuminate in the first illumination mode.

[0043] Summary of Second Embodiment According to the driving assistance device 1 of the second embodiment as described above, it is possible to appropriately control the lighting devices 3, as in the case of the first embodiment. Furthermore, in the second embodiment, the lighting devices 3 include the headlights 31 and the sub-lights 32, so that it is possible to illuminate the lane ahead of the vehicle with the headlights 31 while illuminating branching roads with the sub-lights 32.

[0044] In the second embodiment, if a branch road directly connected to the traveling lane exists and it is not determined that the vehicle is traveling in the first illumination section, illumination of the first illumination mode of the sub-light 32 is stopped. Because the visual difference for the driver between a state in which the sub-light 32 is illuminating and a state in which the sub-light 32 is not illuminating is relatively large, the above configuration allows the driver to easily recognize the existence of a branch road when the sub-light 32 is illuminating.

[0045] <First Modification of Second Embodiment> In the second embodiment, the lighting device 3 includes a headlight 31 that illuminates the area ahead of the vehicle and a sub-light 32 that provides auxiliary illumination for branching roads, but this is not limited to this. For example, the lighting device 3 may be a single light that has both the function of forward illumination and the function of auxiliary illumination. Furthermore, the sub-light 32 may include a left light that illuminates the area ahead of the vehicle on the left and a right light that illuminates the area ahead of the vehicle on the right.

[0046] <Second Modification of Second Embodiment> In the second embodiment, one branch road exists in the first illumination section. If multiple branch roads exist in the first illumination section, the illumination control unit 12a may cause the sub-light 32 to illuminate the multiple branch roads simultaneously. If the sub-light 32 does not have the function of illuminating multiple branch roads simultaneously, the illumination control unit 12a may cause the sub-light 32 to illuminate the branch roads in order, starting with the branch road closest to the vehicle.

[0047] <Third Modification of Second Embodiment> In the second embodiment, the illumination control unit 12a controls the first illumination mode of the sub-light 32 based on the planar shape of the branching road so that the sub-light 32 illuminates point Q2 on the branching road. However, the present invention is not limited to this. For example, the illumination control unit 12a may calculate the angle between the driving lane and the branching road at the branching point based on road information, and control the first illumination mode of the sub-light 32 based on this angle.

[0048] In the cases of FIGS. 7 to 10 , the illumination control unit 12a calculates the angle θ1 between the left lane 52a, which is the driving lane, and the branch road 53 at the branch point Q1, based on map information. The illumination control unit 12a then controls the major axis of the illumination range 32a of the sublight 32 to face in a direction rotated leftward by the angle θ1 from the front of the vehicle 51 at the branch point Q1. Note that, for example, by using the technology disclosed in Japanese Patent Application Laid-Open No. 2016-30515, the illumination control unit 12a controls the sublight 32 to spot-illuminate the illumination range 32 that matches the shape of the branch road 53, even if the vehicle 51 is not located near the branch point Q1. In FIGS. 7 to 9 , the branch road 53 has a generally linear shape, and therefore the illumination range 32 of the sublight 32 also has a generally linear shape. In FIG. 10 , the branch road 53 has a curved shape, and therefore the illumination range 32 of the sublight 32 also has a generally curved shape.

[0049] In the case of Figure 11, the illumination control unit 12a controls the long axis of the illumination range 32a of the sublight 32 to be oriented in a direction rotated left by the angle θ2 from the front of the vehicle 51 at the branch point Q1, based on the angle θ2 formed by the left lane 52a, which is the driving lane, and the branch road 53 at the branch point Q1.

[0050] In the second embodiment, the headlights 31 illuminate the area ahead of the vehicle in a straight line, but the present invention is not limited to this. For example, the illumination control unit 12a may control the illumination mode of the headlights 31 based on the planar shape of the driving lane, and may also control the first illumination mode of the sub-lights 32 based on the planar shape of the branching road.

[0051] As the illumination mode of the headlights 31, the illumination control unit 12a may control the direction and shape of the illumination range of the headlights 31 based on the planar shape of the driving lane. For example, if the driving lane is a lane that curves to the right (or left), the illumination control unit 12a may control the illumination range of the headlights 31 so that the shape of the illumination range of the headlights 31 corresponds to the shape of the curve of the driving lane. Furthermore, for example, if the road information indicates the gradient of the driving lane, that is, the inclination of the driving lane, the illumination control unit 12a may control the up / down direction of the illumination of the headlights 31. According to this fourth modification, the driving lane can be appropriately illuminated by the headlights 31.

[0052] <Fifth Modification of Second Embodiment> In the second embodiment, the gradient of the traveling lane and the gradient of the branching road are assumed to be the same. However, in reality, these gradients often differ. Therefore, the illumination control unit 12a may read the gradient of the traveling lane and the gradient of the branching road from the road information, and control the vertical direction of illumination of the sub-light 32 based on the difference between these gradients, thereby controlling the first illumination mode of the sub-light 32. According to this fifth modification, the sub-light 32 can illuminate the branching road up to an appropriate distance.

[0053] In addition, if the road information indicates that the difference between the gradient of the driving lane and the gradient of the branch road is greater than or equal to a threshold value, the first illumination mode of the sub-light 32 may include illuminating at least one of letters, figures, and symbols indicating the difference.

[0054] <Sixth Modification of Second Embodiment> The driving assistance device 1 may include a route information acquisition unit (not shown) that is included in the concept of the acquisition unit 11, similar to the road information acquisition unit 11a and the vehicle position acquisition unit 11b in Fig. 2. The route information acquisition unit acquires driving route information indicating a route along which the vehicle should travel. The route along which the vehicle should travel is, for example, a route searched for by a navigation system.

[0055] The illumination control unit 12a may control the first illumination mode of the sub-lights 32 based on whether the route in the driving route information acquired by the route information acquisition unit leads to a branch road. In other words, the illumination control unit 12a may control the first illumination mode of the sub-lights 32 based on whether the vehicle should proceed to a branch road.

[0056] 12 to 14 are diagrams for explaining the operation of the driving assistance device 1 according to the sixth modification.

[0057] 12 is a diagram showing a case where the route indicated by the driving route information proceeds onto a branch road, i.e., a case where the vehicle 51 should proceed onto a branch road 53. FIGS. 13 and 14 are diagrams showing a case where the route indicated by the driving route information does not proceed onto a branch road, i.e., a case where the vehicle 51 should not proceed onto the branch road 53.

[0058] The illumination range 32a of the sub-light 32 in Fig. 12 includes a portion slightly further back from the connection to the branch road 53, whereas the illumination range 32a of the sub-light 32 in Figs. 13 and 14 covers only the connection to the branch road 53. With this configuration, the illumination range 32a of the sub-light 32 in Fig. 12 is larger and more noticeable than the illumination range 32a of the sub-light 32 in Figs. 13 and 14, allowing the driver to easily know whether or not to proceed onto the branch road 53.

[0059] If the route indicated by the driving route information does not lead to a branch road, the sub-light 32 may provide spot illumination over an elliptical area as shown in Fig. 13, or may provide illumination over a normal-shaped area as shown in Fig. 14. The first illumination mode of the sub-light 32 may include illumination encouraging the driver to stay in the driving lane, or may include illumination of at least one of letters, figures, and symbols encouraging the driver to take a branch road.

[0060] In addition, when the lane in which the vehicle 51 is traveling is the right lane 52b, which is indirectly connected to the branch road 53 but not directly, the headlight 31 illuminates the illumination range 31a, but the sublight 32 does not illuminate, as in the second embodiment.

[0061] <Seventh Modification of Second Embodiment> The first illumination section may be changed depending on whether the headlights 31 are using high beams or low beams. For example, when the headlights 31 are using high beams, the first illumination section may be a section of the driving lane within 100 m of the branching point. When the headlights 31 are using low beams, the first illumination section may be a section of the driving lane within 40 m of the branching point.

[0062] 15 is a block diagram showing the configuration of a driving assistance device 1 according to a third embodiment. In the following, among the components according to the third embodiment, components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components will be mainly described.

[0063] The configuration of the driving assistance device 1 in FIG. 15 is the same as that of the driving assistance device 1 in FIG. 2, except that the high-accuracy locator device 2 is replaced with an in-vehicle information system 6 and an image processing device 7.

[0064] The in-vehicle information system 6 includes a normal-accuracy map database (DB) 61 and a locator 62. The normal-accuracy map DB 61 stores road information for each road. The locator 62 detects vehicle position information for each road based on signals from artificial satellites such as GPS. The locator 62 may perform map matching processing based on the detected position information and the road information in the normal-accuracy map DB 61. The normal-accuracy map DB 61 and the locator 62 may be a map DB and a locator dedicated to the driving assistance device 1, or may be a map DB and a locator shared with the navigation system.

[0065] The image processing device 7 recognizes driving lane information indicating the driving lane in which the vehicle is traveling, based on an image of the surroundings of the vehicle (for example, an image in front of the vehicle).

[0066] The road information acquisition unit 11a acquires road information from the normal-accuracy map DB 61. The vehicle position acquisition unit 11b acquires position information and driving lane information from the locator 62 and the image processing device 7, respectively. The illumination control unit 12a and the lighting device 3 are similar to the illumination control unit 12a and the lighting device 3 of the second embodiment.

[0067] Summary of Third Embodiment According to the driving assistance device 1 according to the third embodiment described above, the cost of the driving assistance device 1 can be reduced because the inexpensive normal-accuracy map DB 61 and normal locator 62 are used.

[0068] <First Modification of Third Embodiment> The road information in the normal-accuracy map DB 61 may include the number of lanes, and the image processing device 7 may recognize driving lane information based on an image of the area around the vehicle and the number of lanes. With this configuration, the accuracy of the driving lane information can be improved.

[0069] <Second Modification of Third Embodiment> In the third embodiment, the location information and road information can be acquired from the in-vehicle information system 6, but the present invention is not limited to this.

[0070] 16 , for example, an image processing device 7 may recognize not only driving lane information but also position information and road information based on an image of the surroundings of the vehicle (e.g., an image in front of the vehicle) without providing an in-vehicle information system 6. The road information acquisition unit 11a may acquire road information from the image processing device 7, and the vehicle position acquisition unit 11b may acquire position information and driving lane information from the image processing device 7.

[0071] The image processing device 7 may also include the functions of the road information acquisition unit 11a and the vehicle position acquisition unit 11b, as well as some of the functions of the illumination control unit 12a. For example, the image processing device 7 may determine whether or not a branch road directly connected to the driving lane exists based on the driving lane information and road information. If it is determined that a branch road directly connected to the driving lane exists, the image processing device 7 may calculate the distance between the vehicle position and the branch point based on the position information and the branch point of the branch road. The illumination control unit 12a may control the sub-light 32 to illuminate the branch road in the first illumination mode based on the distance calculated by the image processing device 7.

[0072] In the third embodiment, one of the normal-accuracy map DB 61 and the normal locator 62 included in the in-vehicle information system 6 may be provided, while the function of the other may be realized by the image processing device 7 .

[0073] <Fourth Embodiment> A block diagram of a driving assistance device 1 according to a fourth embodiment is similar to the block diagram (see FIG. 2) of the driving assistance device 1 according to the second embodiment. Hereinafter, among the components according to the fourth embodiment, components that are the same as or similar to the components described above will be assigned the same or similar reference numerals, and different components will be mainly described.

[0074] The illumination control unit 12a according to the fourth embodiment performs the same processing for a merging road as for a branching road. That is, the illumination control unit 12a determines whether a merging road directly connected to the traveling lane exists and whether the vehicle is traveling in the second illumination section, based on the position information, the traveling lane information, and the road information.

[0075] The second illumination section is a section that satisfies a predetermined positional relationship with respect to the junction point of the driving lane and the merging road. In the fourth embodiment, the second illumination section is the same as the first illumination section, and is, for example, a driving lane between the junction point of the driving lane and the merging road and a point that is a predetermined distance (for example, 100 m) away from the junction point toward the vehicle.

[0076] If it is determined as a result of the above determination that a merging road directly connected to the traveling lane exists and that the vehicle is traveling in the second illumination section, the illumination control unit 12a controls the sub-light 32 to illuminate the merging road in the second illumination mode. In the fourth embodiment, the second illumination mode is the same as the first illumination mode. For example, the illumination control unit 12a may control the second illumination mode of the sub-light 32 based on the distance between the position of the vehicle and the merging point.

[0077] <Operation> Fig. 17 is a flowchart showing the operation of the driving assistance device 1 according to the embodiment 4. The operation shown in Fig. 3 is performed whenever the vehicle is traveling.

[0078] First, in steps S1 to S7, the same operations as in steps S1 to S7 in Fig. 3 are performed. After step S6 or step S7, the process of step S11 is performed.

[0079] In step S11, the illumination control unit 12a determines whether or not there is a merging road directly connected to the driving lane based on the driving lane information and road information. If it is determined that there is a merging road, the process proceeds to step S12, and if it is not determined that there is a merging road, the process proceeds to step S14.

[0080] In step S12, the illumination control unit 12a determines whether the vehicle is traveling in the second illumination section based on the merging road determined in step S11 and the position information. If it is determined that the vehicle is traveling in the second illumination section, the process proceeds to step S13, and if it is not determined that the vehicle is traveling in the second illumination section, the process proceeds to step S14.

[0081] In step S13, the illumination control unit 12a turns on the sub-light 32 and controls the sub-light 32 to illuminate the merging road in the second illumination mode. The illumination of the headlight 31 is maintained unless the driver performs an operation to turn off the headlight 31. Then, the process proceeds to step S8.

[0082] In step S14, the illumination control unit 12a stops the illumination by the sublight 32 in the second illumination mode if the sublight 32 is illuminating in the second illumination mode. The illumination by the headlight 31 is maintained unless the driver performs an operation to turn off the headlight 31. Then, the process proceeds to step S8.

[0083] In step S8, the illumination control unit 12a determines whether or not the headlights 31 are turned off. If it is determined that the headlights 31 are turned off, the operation in Fig. 17 ends, and if it is not determined that the headlights 31 are turned off, the process returns to step S2.

[0084] As a result of the above operation, if the traveling lane is not directly connected to either a branching road or a merging road, the sublight 32 is not illuminated, and in principle, only the headlight 31 is illuminated. If there are both a branching road and a merging road directly connected to the traveling lane, the illumination control unit 12a may cause the sublight 32 to illuminate the branching road and the merging road simultaneously. If the sublight 32 does not have the function of illuminating the branching road and the merging road simultaneously, the sublight 32 may illuminate the branching road and the merging road in order of the road closest to the vehicle, or with priority given to the branching road.

[0085] Summary of Fourth Embodiment According to the driving assistance device 1 of the fourth embodiment as described above, when it is determined that there is a merging road directly connected to the traveling lane and that the vehicle is traveling in the second illumination section, control is performed to cause the sub-light 32 to illuminate the merging road in the second illumination mode. With this configuration, it is possible to control the sub-light 32 to illuminate the merging road in a section where the vehicle is an appropriate distance away from the merging point, and therefore it is possible to appropriately control the sub-light 32.

[0086] <First Modification of Fourth Embodiment> In the fourth embodiment, the second irradiation mode has been described as being the same as the first irradiation mode, but the first irradiation mode and the second irradiation mode may be different from each other.

[0087] As a first example, the color tone of the irradiation in the first irradiation mode may be different from the color tone of the irradiation in the second irradiation mode.

[0088] As a second example, the illumination range 32a in the first illumination mode for a branching road includes a portion slightly further from the connecting opening of the branching road as shown in Figures 4 and 5, while the illumination range 32b in the second illumination mode for a merging road may include only the connecting opening of the merging road 54 as shown in Figures 18 and 19. As the second illumination mode for a merging road, the sub-light 32 may provide spot illumination of an elliptical area as shown in Figure 18, or the sub-light 32 may illuminate a normal-shaped area as shown in Figure 19. Note that Figures 18 and 19 illustrate a merging point Q3 between the left lane 52a, which is the driving lane, and the merging road 54.

[0089] For example, the first illumination mode for a branching road may include illumination of at least one of letters, figures, and symbols indicating the branching road, and the second illumination mode for a merging road may include illumination of at least one of letters, figures, and symbols indicating the merging road.

[0090] <Variation 2 of Embodiment 4> In the fourth embodiment, the second illumination section has been described as being the same as the first illumination section, but the first illumination section and the second illumination section may be different from each other. For example, at a merging point, there is a possibility of a collision between a vehicle traveling in the driving lane and a vehicle traveling on the merging road, and there is also a tendency for vehicles to change lanes to avoid the merging road. In consideration of this, the second illumination section may be longer than the first illumination section.

[0091] <Third Modification of Fourth Embodiment> In the fourth embodiment, the illumination control unit 12a has been described assuming that the sub-light 32 continuously illuminates the merging road in the second illumination mode. However, the illumination control unit 12a may also cause the sub-light 32 to intermittently illuminate the merging road when the distance between the merging point and the vehicle is equal to or less than a threshold. Furthermore, the illumination control unit 12a may appropriately increase or decrease the size of the illumination range 32b of the sub-light 32 in the second illumination mode.

[0092] 2, the driving assistance device 1 may include a moving object detection unit (not shown) that is included in the concept of the acquisition unit 11. The moving object detection unit is, for example, any of various radars, and is configured to be able to detect moving objects such as vehicles heading from a merging road toward a merging point.

[0093] The illumination control unit 12a may control the second illumination mode based on whether a moving object is detected by the moving object detection unit. For example, the illumination control unit 12a may make the sub-light 32 more conspicuous by increasing the illumination range of the sub-light 32 when a moving object is detected compared to the illumination range of the sub-light 32 when a moving object is not detected. Furthermore, for example, the illumination control unit 12a may cause the sub-light 32 to illuminate the merging road in the second illumination mode when a moving object is detected, and stop the illumination of the sub-light 32 in the second illumination mode when a moving object is not detected. This configuration can alert the driver to be careful of moving objects and suppress unnecessary illumination of the sub-light 32.

[0094] <Fifth Modification of Fourth Embodiment> In a fourth modification of the fourth embodiment, the illumination control unit 12a may control the second illumination mode based on the type of moving object detected by the moving object detection unit. For example, if the moving object is a vehicle using headlights, the illumination control unit 12a may stop illumination of the sub-light 32 in the second illumination mode, and if the moving object is not a vehicle using headlights, the illumination control unit 12a may cause the sub-light 32 to illuminate the merging road in the second illumination mode. Furthermore, if the moving object is a pedestrian or a bicycle, the illumination control unit 12a may increase the illumination range of the sub-light 32 to make the moving object more noticeable. In this case, the merging road may be a sidewalk at an intersection or a bicycle-only lane.

[0095] <Sixth Modification of Fourth Embodiment> The illumination control unit 12a may read the type of the merging road from the road information and control the second illumination mode based on the type of the merging road. For example, if the width of the merging road is equal to or smaller than a threshold, there is a relatively high possibility that a pedestrian or a cyclist will suddenly appear from the merging road. Therefore, the illumination control unit 12a may increase the illumination range of the sub-light 32 as the width of the merging road becomes narrower, thereby making the merging road more conspicuous. Furthermore, for example, if the merging road is a motorway, there is a relatively high possibility that a pedestrian or a cyclist will suddenly appear from the merging road. Therefore, the illumination control unit 12a may reduce the illumination range of the sub-light 32 so that the merging road is not excessively conspicuous.

[0096] <Fifth Embodiment> A block diagram of a driving assistance device 1 according to a fifth embodiment is similar to the block diagram (see FIG. 2) of the driving assistance device 1 according to the second embodiment. Hereinafter, among the components according to the fifth embodiment, components that are the same as or similar to the components described above will be assigned the same or similar reference numerals, and different components will be mainly described.

[0097] The illumination control unit 12a according to the fifth embodiment performs the same processing for a branch road indirectly connected to a driving lane as for a branch road directly connected to the driving lane. Hereinafter, a branch road directly connected to a driving lane may be referred to as a "direct branch road," and a branch road indirectly connected to a driving lane may be referred to as an "indirect branch road."

[0098] The illumination control unit 12a determines whether an indirect branch road exists and whether the vehicle is traveling in the third illumination section based on the position information, the driving lane information, and the road information.

[0099] The third illumination section is a section that satisfies a predetermined positional relationship with respect to the indirect branch point between the driving lane and the indirect branch road. The indirect branch point Q4 is a point on the driving lane (the right lane 52b in FIG. 20) where the connection to the indirect branch road 55 is located in the width direction of the driving lane, as shown in FIG. 20. In the fifth embodiment, the third illumination section is similar to the first illumination section, and is, for example, a driving lane between the indirect branch point Q4 and a point that is a predetermined distance (e.g., 100 m) away from the indirect branch point toward the vehicle.

[0100] If it is determined as a result of the above determination that an indirect branch road exists and that the vehicle is traveling in the third illumination section, the illumination control unit 12a controls the sub-light 32 to illuminate the indirect branch road in a third illumination mode different from the first illumination mode. For example, the illumination range 32a of the first illumination mode for the branch road 53 includes a portion slightly further back from the connection port of the branch road 53 as shown in Fig. 4, while the illumination range 32c of the third illumination mode for the indirect branch road 55 includes only a portion near the connection port of the indirect branch road 55 as shown in Fig. 20. As the third illumination mode for the indirect branch road 55, the sub-light 32 may spot illuminate an elliptical area as shown in Fig. 20, or may perform other illumination.

[0101] The first illumination mode for the direct branch road and the third illumination mode for the indirect branch road may have different color tones or illuminances. The first illumination mode may include illumination of at least one of a character, a graphic, and a symbol indicating the direct branch road, and the third illumination mode may include illumination of at least one of a different character, a graphic, and a symbol indicating the indirect branch road.

[0102] <Operation> Fig. 21 is a flowchart showing the operation of the driving assistance device 1 according to the embodiment 5. The operation shown in Fig. 3 is performed whenever the vehicle is traveling.

[0103] First, in steps S1 to S7, the same operations as in steps S1 to S7 in Fig. 3 are performed. After step S6 or step S7, the process of step S21 is performed.

[0104] In step S21, the illumination control unit 12a determines whether or not an indirect branch road exists. If it is determined that an indirect branch road exists, the process proceeds to step S22. If it is determined that an indirect branch road does not exist, the process proceeds to step S24.

[0105] In step S22, the illumination control unit 12a determines whether the vehicle is traveling in the third illumination section based on the indirect branch road determined in step S21 and the position information. If it is determined that the vehicle is traveling in the third illumination section, the process proceeds to step S23. If it is not determined that the vehicle is traveling in the third illumination section, the process proceeds to step S24.

[0106] In step S23, the illumination control unit 12a turns on the sub-light 32 and controls the sub-light 32 to illuminate the indirect branch road in the third illumination mode. The illumination of the headlight 31 is maintained unless the driver performs an operation to turn off the headlight 31. Then, the process proceeds to step S8.

[0107] In step S24, the illumination control unit 12a stops the illumination by the sublight 32 in the third illumination mode if the sublight 32 is illuminating in the third illumination mode. The illumination by the headlight 31 is maintained unless the driver performs an operation to turn off the headlight 31. Then, the process proceeds to step S8.

[0108] In step S8, the illumination control unit 12a determines whether or not the headlights 31 are turned off. If it is determined that the headlights 31 are turned off, the operation in Fig. 21 ends, and if it is not determined that the headlights 31 are turned off, the process returns to step S2.

[0109] As a result of the above operations, if the driving lane is not directly connected to either a direct branch road or an indirect branch road, the sublight 32 is not illuminated, and in principle, only the headlight 31 is illuminated. If both a direct branch road and an indirect branch road exist, the illumination control unit 12a may cause the sublight 32 to illuminate the direct branch road and the indirect branch road simultaneously. If the sublight 32 does not have the function of illuminating the direct branch road and the indirect branch road simultaneously, the sublight 32 may illuminate the direct branch road and the indirect branch road in order of closest to the vehicle, or may prioritize the direct branch road.

[0110] Summary of Fifth Embodiment According to the driving assistance device 1 of the fifth embodiment described above, when it is determined that an indirect branch road exists and that the vehicle is traveling in the third illumination section, control is performed to cause the sub-light 32 to illuminate the indirect branch road in a third illumination mode different from the first illumination mode. With this configuration, it is possible to control the sub-light 32 to illuminate the indirect branch road in a section where the vehicle is an appropriate distance away from the indirect branch point, and therefore it is possible to appropriately control the sub-light 32.

[0111] <First Modification of Fifth Embodiment> In the fifth embodiment, the case where the road has two lanes has been described, but the road may have three or more lanes, and the illumination control unit 12a may control the third illumination mode for the indirect branch road based on which of the three or more lanes the traveling lane is. For example, the illumination range of the third illumination mode may be made less noticeable as the number of other lanes between the indirect branch road and the traveling lane increases, or illumination of the sub-light 32 in the third illumination mode may be stopped when the number of other lanes is equal to or greater than a threshold.

[0112] <Variation 2 of Embodiment 5> In the description of Embodiment 5, the illumination control unit 12a is assumed to cause the sub-light 32 to continuously illuminate the indirect branch road as the third illumination mode. However, this is not limited to this. For example, the illumination control unit 12a may cause the sub-light 32 to intermittently illuminate the indirect branch road when the distance between the indirect branch point and the vehicle becomes equal to or less than a threshold. Furthermore, the illumination control unit 12a may appropriately increase or decrease the size of the illumination range 32c of the sub-light 32 in the third illumination mode. Furthermore, the third illumination mode for the indirect branch road may include illumination of at least one of a character, a graphic, and a symbol indicating the indirect branch road.

[0113] <Variation 3 of Embodiment 5> In the fifth embodiment, the third illumination section has been described as being the same as the first illumination section, but the first illumination section and the third illumination section may be different from each other. For example, the third illumination section may be longer than the first illumination section, taking into consideration the time it takes for a vehicle to change lanes to head toward an indirect branch road.

[0114] <Fourth Modification of Fifth Embodiment> The illumination control unit 12a may determine whether the vehicle can proceed onto the indirect branch road based on road information and vehicle position information, and may control the third illumination mode based on the determination result. For example, when the vehicle is located at a point where it cannot proceed onto the indirect branch road even if it changes lanes, the illumination control unit 12a may stop illumination of the sub-light 32 in the third illumination mode. Specifically, since the vehicle is required to turn on its turn signal three seconds before changing lanes, when the vehicle 51 reaches a point where it will reach the indirect branch point Q4 in three seconds, as shown in Figure 22, the illumination control unit 12a may stop illumination of the sub-light 32 in the third illumination mode.

[0115] <Fifth Variation of the Fifth Embodiment> In the fifth embodiment, the illumination control unit 12a may determine, based on the road information and the vehicle position information, whether or not the vehicle is prohibited from proceeding onto the indirect branch road by law or the like, and control the third illumination mode based on the determination result.

[0116] For example, assume that the lane in which the vehicle is traveling is the right lane, and there is a branch road directly connected to the left lane. Since the branch road directly connected to the left lane is an indirect branch road for the right lane, the sub-light 32 is generally irradiated in the third illumination mode onto the indirect branch road. However, if changing lanes from the right lane to the left lane is prohibited by law, the illumination control unit 12a may stop irradiating the indirect branch road with the sub-light 32 in the third illumination mode.

[0117] <Sixth Modification of Fifth Embodiment> In the fifth embodiment, similar to the sixth modification of the second embodiment, the driving assistance device 1 may include a route information acquisition unit that acquires driving route information indicating a route along which the vehicle should travel. The illumination control unit 12a may then control the third illumination mode of the sub-light 32 based on whether the route according to the driving route information acquired by the route information acquisition unit leads to an indirect branch road. For example, the illumination range of the sub-light 32 when the vehicle should proceed onto the indirect branch road may be set larger and more conspicuous than the illumination range of the sub-light 32 when the vehicle should not proceed onto the indirect branch road.

[0118] <Variant 7 of Embodiment 5> The first illumination mode for the branch road in Embodiment 2, the second illumination mode for the merging road in Embodiment 4, and the third illumination mode for the indirect branch road in Embodiment 5 may be combined.

[0119] In the example of Fig. 23, there is a branch road 53 directly connected to the left lane 52a, which is the driving lane. In this case, illumination of the branch road 53 is performed in the first illumination mode. In the example of Fig. 24, there is a merging road 54 directly connected to the right lane 52b, which is the driving lane, and an indirect branch road 55 indirectly connected to the right lane 52b. In this case, illumination of the merging road 54 in the second illumination mode and illumination of the indirect branch road 55 in the third illumination mode may be performed in parallel.

[0120] <Eighth Modification of Fifth Embodiment> The illumination control unit 12a may perform the same processing as for an indirect branch road with respect to an intersecting flow road, which is a merging road indirectly connected to a traveling lane. That is, the illumination control unit 12a may determine, based on the position information, the traveling lane information, and the road information, whether an intersecting flow road exists and whether the vehicle is traveling in the fourth illumination section that satisfies a predetermined positional relationship with respect to the intersecting flow point between the traveling lane and the intersecting flow road.

[0121] 25, the inter-section junction flow point Q5 is a point on the travel lane (the left lane 52a in FIG. 25) where a connection opening of the inter-section junction flow road 56 exists in the width direction of the travel lane. The fourth illumination section may or may not be the same as any of the first illumination section, the second illumination section, and the third illumination section.

[0122] Then, when it is determined that an indirect branch road exists and the vehicle is traveling in the fourth illumination section, the illumination control unit 12a may control the sub-light 32 to illuminate the indirect branch road in a fourth illumination mode different from the first to third illumination modes.

[0123] The first irradiation mode for the branching road in embodiment 2, the second irradiation mode for the merging road in embodiment 4, the third irradiation mode for the indirect branching road in embodiment 5, and the fourth irradiation mode for the junction road in this variant example 8 may be combined.

[0124] In the example of Fig. 25, there is a branch road 53 directly connected to the left lane 52a, which is the driving lane, and an inter-junction flow road 56 indirectly connected to the left lane 52a. In such a case, illumination of the branch road 53 in the first illumination mode and illumination of the inter-junction flow road 56 in the fourth illumination mode may be performed in parallel. Also, as shown in Fig. 25, the illumination range 32d of the fourth illumination mode for the inter-junction flow road may be made less noticeable than the illumination range 32a of the first illumination mode for the direct branch road.

[0125] Also, modifications similar to those of direct merging roads or indirect diverging roads may be made to inter-junction flow roads.

[0126] For example, the same modification as in Modification 4 of Embodiment 4 (i.e., a modification of a direct merging road) may be applied to the inter-junction flow road. Specifically, the moving object detection unit may be capable of detecting a moving object heading from the inter-junction flow road toward the inter-junction flow point, and the illumination control unit 12a may control the fourth illumination mode based on whether the moving object detection unit detects a moving object heading from the inter-junction flow road toward the inter-junction flow point. More specifically, the illumination control unit 12a may cause the sub-light 32 to illuminate the inter-junction flow road in the fourth illumination mode when a moving object is detected, and may stop illumination of the sub-light 32 in the fourth illumination mode when a moving object is not detected.

[0127] For example, the same modification as in Modification 5 of Embodiment 5 (i.e., a modification of the indirect branch road) may be performed on the inter-junction flow road. Specifically, the illumination control unit 12a may determine whether or not the advance of the vehicle onto the inter-junction flow road is prohibited by law or regulation based on the road information and the vehicle position information, and control the fourth illumination mode based on the determination result.

[0128] For example, assume that the lane in which the vehicle 51 is traveling is the left lane 52a, and there is a merging road directly connected to the right lane 52b, as shown in Figure 26. The merging road directly connected to the right lane 52b is an inter-flow road 56 for the left lane 52a, and therefore, in principle, the sub-light 32 is irradiated in the fourth irradiation mode onto the inter-flow road 56. However, if there is a center line 58 between the left lane 52a and the right lane 52b, where lane changes are prohibited by law, as shown in Figure 26, the illumination control unit 12a may stop irradiating the inter-flow road 56 with the sub-light 32 in the fourth irradiation mode.

[0129] <Other Modifications> The acquisition unit 11 and control unit 12 in FIG. 1 described above will be referred to as the "acquisition unit 11, etc." The acquisition unit 11, etc., are implemented by a processing circuit 81 shown in FIG. 27 . That is, the processing circuit 81 includes the acquisition unit 11 that acquires vehicle position information, driving lane information indicating the driving lane in which the vehicle is traveling, and road information, and the control unit 12 that controls the lighting device to illuminate the branch road in a first illumination mode when it is determined, based on the position information, the driving lane information, and the road information, that there is a branch road directly connected to the driving lane and that the vehicle is traveling in a first illumination section that satisfies a predetermined positional relationship with respect to the branch point between the driving lane and the branch road. The processing circuit 81 may be implemented by dedicated hardware, or may be implemented by a processor that executes a program stored in a memory. Examples of the processor include a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, and a DSP (Digital Signal Processor).

[0130] When the processing circuitry 81 is dedicated hardware, the processing circuitry 81 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The functions of each unit, such as the acquisition unit 11, may be realized by a circuit in which processing circuits are distributed, or the functions of each unit may be realized together by a single processing circuit.

[0131] When the processing circuit 81 is a processor, the functions of the acquisition unit 11 and the like are realized in combination with software and the like. The software and the like may include, for example, software, firmware, or both software and firmware. The software and the like is written as a program and stored in a memory. As shown in FIG. 28 , the processor 82 applied to the processing circuit 81 realizes the functions of each unit by reading and executing a program stored in a memory 83. That is, the driving assistance device 1 includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the following steps: acquiring vehicle position information, driving lane information indicating the driving lane in which the vehicle is traveling, and road information; and, when it is determined, based on the position information, driving lane information, and road information, that there is a branch road directly connected to the driving lane and that the vehicle is traveling in a first illumination section that satisfies a predetermined positional relationship with respect to the branch point between the driving lane and the branch road, controlling the lighting devices to illuminate the branch road in a first illumination mode. In other words, this program can be said to cause a computer to execute the procedures and methods of the acquisition unit 11 and the like. Here, the memory 83 may be, for example, 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), or an EEPROM (Electrically Erasable Programmable Read Only Memory), a HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), a drive device for any of these, or any storage medium to be used in the future.

[0132] The above describes a configuration in which each function of the acquisition unit 11, etc. is realized either by hardware or software, etc. However, the present invention is not limited to this, and a configuration in which part of the acquisition unit 11, etc. is realized by dedicated hardware and another part is realized by software, etc. For example, the functions of the acquisition unit 11 can be realized by dedicated hardware such as a processing circuit 81, an interface, and a receiver, and the other functions can be realized by the processing circuit 81 as a processor 82 reading and executing a program stored in a memory 83.

[0133] As described above, the processing circuitry 81 can realize the above-described functions by hardware, software, or a combination of these.

[0134] The driving assistance device described above can also be applied to a driving assistance system constructed as a system by appropriately combining various vehicle devices, communication terminals including mobile devices such as mobile phones, smartphones, and tablets, functions of applications installed in at least one of the vehicle devices and the communication terminals, and a server. In this case, the functions or components of the driving assistance device described above may be distributed among the devices that construct the system, or may be concentrated in one of the devices.

[0135] Fig. 29 is a block diagram showing the configuration of a server 91 according to this modification. The server 91 in Fig. 29 includes a communication unit 91a and a control unit 91b, and is capable of wireless communication with a vehicle device 93 of a vehicle 92.

[0136] The communication unit 91 a, which is an acquisition unit, receives vehicle position information, driving lane information, and road information acquired by the vehicle device 93 by wirelessly communicating with the vehicle device 93 .

[0137] The control unit 91b has the same functions as the control unit 12 in FIG. 1 , by having a processor (not shown) of the server 91 execute a program stored in a memory (not shown) of the server 91. That is, when the control unit 91b determines, based on the position information, the driving lane information, and the road information, that there is a branch road directly connected to the driving lane and that the vehicle is traveling in the first illumination section, the control unit 91b generates a control signal for controlling the lighting devices 3 to illuminate the branch road in the first illumination mode. The communication unit 91a then transmits the control signal of the control unit 91b to the vehicle device 93. The server 91 configured in this manner can achieve the same effects as the driving assistance device 1 described in the first embodiment.

[0138] Fig. 30 is a block diagram showing the configuration of a communication terminal 96 according to this modification. The communication terminal 96 in Fig. 30 includes a communication unit 96a similar to the communication unit 91a and a control unit 96b similar to the control unit 91b, and is capable of wireless communication with a vehicle device 98 of a vehicle 97. Note that the communication terminal 96 may be, for example, a mobile terminal such as a mobile phone, smartphone, or tablet carried by the driver of the vehicle 97. The communication terminal 96 configured in this manner can achieve the same effects as the driving assistance device 1 described in the first embodiment.

[0139] It should be noted that the embodiments and modifications may be freely combined, and the embodiments and modifications may be modified or omitted as appropriate.

[0140] The above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0141] 1 Driving assistance device, 2 High-precision locator device, 3 Lighting device, 7 Image processing device, 11 Acquisition unit, 12 Control unit, 21 High-precision map database, 22 High-precision positioning unit, 31 Headlight, 32 Sublight, 51 Vehicle, 53 Branching road, 54 Merging road, 55 Indirect branching road, 61 Normal precision map database, Q1 Branching point, Q3 Merging point, Q4 Indirect branching point.

Claims

1. A driving assistance device that controls lighting devices that illuminate a road from a vehicle, comprising: an acquisition unit that acquires position information of the vehicle, driving lane information that indicates the driving lane in which the vehicle is traveling, and road information; and a control unit that, when it is determined based on the position information, the driving lane information, and the road information that there is a branch road that is directly connected to the driving lane and the vehicle is traveling in a first illumination section that satisfies a predetermined positional relationship with respect to a branch point between the driving lane and the branch road, controls the lighting device to illuminate the branch road in a first illumination mode.

2. A driving assistance device as described in claim 1, wherein the acquisition unit acquires the road information from a high-precision map database of a high-precision locator device that stores the road information on a lane-by-lane basis, and acquires the position information and the driving lane information from a high-precision positioning unit of the high-precision locator device that detects the position information and the driving lane information.

3. A driving assistance device as described in claim 1, wherein the acquisition unit acquires the road information from a normal precision map database that stores the road information on a road-by-road basis, and acquires the driving lane information from an image processing device that recognizes the driving lane information based on an image of the area around the vehicle.

4. A driving assistance device as described in claim 1, wherein the acquisition unit acquires the road information, the position information, and the driving lane information from an image processing device that recognizes the road information, the position information, and the driving lane information based on an image of the area around the vehicle.

5. A driving assistance device according to claim 1, wherein the control unit controls the first illumination mode based on an angle formed between the driving lane and the branch road at the branch point.

6. A driving assistance device as described in claim 1, wherein the lighting device includes a headlight and a sublight, and the control unit controls the illumination mode of the headlight based on the planar shape of the driving lane, and controls the first illumination mode of the sublight based on the planar shape of the branching road.

7. A driving assistance device according to claim 1, wherein the control unit controls the first illumination mode based on the difference between the gradient of the driving lane and the gradient of the branch road.

8. A driving assistance device as described in claim 1, wherein the acquisition unit further acquires driving route information indicating a route on which the vehicle should travel, and the control unit controls the first illumination mode based on whether the route in the driving route information proceeds to the branch road.

9. A driving assistance device as described in claim 1, wherein the control unit controls the lighting device to illuminate the merging road in a second illumination mode when it is determined, based on the position information, the driving lane information, and the road information, that there is a merging road directly connected to the driving lane and that the vehicle is traveling in a second illumination section that satisfies a predetermined positional relationship with respect to the merging point between the driving lane and the merging road.

10. A driving assistance device according to claim 9, wherein the first illumination section and the second illumination section are different from each other.

11. A driving assistance device as described in claim 9, wherein the acquisition unit is capable of detecting a moving object heading toward the merging point from the merging road, and the control unit controls the second illumination mode based on whether the moving object is detected by the acquisition unit.

12. A driving assistance device according to claim 9, wherein the control unit controls the second illumination mode based on the type of the merging road.

13. A driving assistance device as described in claim 1, wherein the control unit, when it is determined based on the position information, the driving lane information, and the road information that there is an indirect branch road that is a branch road indirectly connected to the driving lane, and that the vehicle is traveling in a third illumination section that satisfies a predetermined positional relationship with respect to the indirect branch point between the driving lane and the indirect branch road, controls the lighting device to illuminate the indirect branch road in a third illumination mode different from the first illumination mode.

14. A driving assistance device according to claim 13, wherein the third illumination mode includes illumination of at least one of a character, a figure, and a symbol.

15. A driving assistance device according to claim 13, wherein the first illumination section and the third illumination section are different from each other.

16. A driving assistance device according to claim 13, wherein the control unit controls the third illumination mode based on whether or not the vehicle can proceed onto the indirect branch road.

17. A driving assistance device according to claim 13, wherein the control unit controls the third illumination mode based on whether or not the vehicle is prohibited from proceeding onto the indirect branch road.

18. A driving assistance device as described in claim 13, wherein the acquisition unit further acquires driving route information indicating a route on which the vehicle should travel, and the control unit controls the third illumination mode based on whether the route in the driving route information proceeds to the indirect branch road.

19. A driving assistance device as described in claim 9, wherein the control unit, when it is determined based on the position information, the driving lane information, and the road information that an indirect branch road exists that is a branch road indirectly connected to the driving lane, and that the vehicle is traveling in a third illumination section that satisfies a predetermined positional relationship with respect to the indirect branch point between the driving lane and the indirect branch road, controls the lighting device to illuminate the indirect branch road in a third illumination mode different from the first illumination mode.

20. A driving assistance method for controlling lighting devices that illuminate a road from a vehicle, the method comprising: acquiring position information of the vehicle, driving lane information indicating the driving lane in which the vehicle is traveling, and road information; and, when it is determined based on the position information, the driving lane information, and the road information that there is a branch road directly connected to the driving lane and that the vehicle is traveling in a first illumination section that satisfies a predetermined positional relationship with respect to the branch point between the driving lane and the branch road, controlling the lighting device to illuminate the branch road in a first illumination mode.