Driving assistance device and driving assistance method

Abstract

A driving assistance device (10) comprises: a road shape information acquisition unit (11) that acquires information about the shape of a road on which a host vehicle (100) is traveling; a side wall information acquisition unit (12) that acquires information about whether a side wall is present on the road; a brightness determination unit (13) that determines whether the brightness of the surroundings is brightness for which assistance irradiation is required, the assistance irradiation being irradiation with light which prompts the driver to recognize the shape of the road; an assistance irradiation determination unit (14) that determines whether to perform the assistance irradiation on the basis of the presence or absence of the side wall of the road, the shape of the road, and the determination result of the brightness of the surroundings; and an assistance irradiation control unit (15) that controls a lighting device (20) to perform assistance irradiation. The assistance irradiation determination unit (14) determines that the assistance irradiation is to be performed when the side wall is present on the road, the road is curved in the lateral direction or the vertical direction, and the brightness of the surroundings is determined to be the brightness for which the assistance irradiation is required. The assistance irradiation control unit (15) performs assistance irradiation by irradiating the side wall of the road with at least portion of the light.

Description

[Technical Field]

[0001] The present disclosure relates to a driving assistance device that assists in driving a vehicle. [Background technology]

[0002] Patent Document 1 listed below discloses a driving assistance device that improves the visibility of the road surface on a curved road by adjusting the optical axis direction of the vehicle's headlights to match the shape of the road. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-59839 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when the color tones (hue, saturation, brightness, etc.) of the road sidewalls and the road surface are similar, or when the color tones of the road markings and the road surface are similar, it may be difficult for the driver to recognize the shape of the road even when the road surface is illuminated with headlights. Therefore, a technology that improves the driver's recognition of the road shape is desired.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a driving assistance device that can improve the driver's awareness of the shape of the road. [Means for solving the problem]

[0006] a brightness determination unit that determines whether the brightness around the host vehicle is bright enough to require the implementation of support illumination, which is illumination of light that encourages the driver of the host vehicle to recognize the shape of the road; a support illumination determination unit that determines whether support illumination is to be implemented based on the determination results of the presence or absence of side walls on the road, the shape of the road, and the brightness around the host vehicle; and a support illumination control unit that controls the lighting devices of the host vehicle to implement support illumination when it is determined that support illumination is to be implemented. When it is determined that a side wall is present on the road, the road is curved laterally or vertically, and the brightness around the host vehicle is bright enough to require the implementation of support illumination, the support illumination determination unit determines that support illumination should be implemented, and the support illumination control unit implements support illumination by irradiating at least a portion of light onto the side walls of the road. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to improve a driver's awareness of the shape of the road.

[0008] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing a configuration of a driving assistance device according to a first embodiment. [Figure 2] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 3] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 4] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 5] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 6] 4 is a flowchart showing the operation of the driving assistance device according to the first embodiment. [Figure 7] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 8]FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 9] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 10] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 11] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 12] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 13] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 14] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 15] FIG. 10 is a diagram showing an example of assisted irradiation. [Figure 16] FIG. 10 is a diagram showing a configuration of a vehicle system according to a second embodiment. [Figure 17] 6 is a flowchart showing the operation of the driving assistance device according to the second embodiment. [Figure 18] 10 is a flowchart showing the operation of the driving assistance device according to the third embodiment. [Figure 19] FIG. 2 is a diagram illustrating an example of a hardware configuration of a driving assistance device. [Figure 20] FIG. 2 is a diagram illustrating an example of a hardware configuration of a driving assistance device. DETAILED DESCRIPTION OF THE INVENTION

[0010] <First Embodiment> 1 is a diagram showing the configuration of a driving assistance device 10 according to the first embodiment. In this embodiment, it is assumed that the driving assistance device 10 is incorporated into a vehicle system 1. Hereinafter, a vehicle 100 equipped with the vehicle system 1 incorporating the driving assistance device 10 will be referred to as a "host vehicle."

[0011] The driving assistance device 10 is connected to the lighting device 20, the map database 31, the positioning device 32, and the surroundings detection device 33 of the vehicle system 1.

[0012] The lighting device 20 includes a headlight 21 and a sublight 22. The headlight 21 is a general lamp that emits light to ensure visibility ahead of the vehicle 100 at night or when driving in a tunnel. The sublight 22 is a lamp that performs support illumination, which is illumination of light to assist the driver of the vehicle 100 in driving, and is capable of controlling the direction and manner of illumination of the light. Note that the headlight 21 may be used for support illumination as long as the direction and manner of illumination of the light are controllable.

[0013] The map database 31 is a database that stores map data. The map data stored in the map database 31 need only include information on the location and shape of roads, but may also include information on the presence or absence of road sidewalls.

[0014] The positioning device 32 is a device that measures the position of the vehicle 100 based on positioning signals received from GNSS (Global Navigation Satellite System) satellites.

[0015] The surroundings detection device 33 is a device that detects information about the surrounding environment of the vehicle 100, and is configured by, for example, a LiDAR (Light Detection and Ranging), a millimeter wave radar, an in-vehicle camera, or the like.

[0016] The driving assistance device 10 performs assistance illumination by controlling the lighting devices 20 based on information acquired from the lighting devices 20, the map database 31, the positioning device 32, and the periphery detection device 33. The assistance illumination in this embodiment is illumination of light to encourage the driver of the vehicle 100 to recognize the shape of the road, and is performed by irradiating at least a part of the light onto the side walls of the road.

[0017] As shown in FIG. 1, the driving assistance device 10 includes a road shape information acquisition unit 11, a sidewall information acquisition unit 12, a brightness determination unit 13, an assistance illumination determination unit 14, and an assistance illumination control unit 15.

[0018] The road shape information acquisition unit 11 compares the position of the host vehicle 100 measured by the positioning device 32 with map data in the map database 31 to identify the road on which the host vehicle 100 is traveling, and acquires information on the shape of the road on which the host vehicle 100 is traveling by reading information on the shape of the road (e.g., radius of curvature, gradient, etc.) from the map database 31. The road shape information acquisition unit 11 acquires at least information on the shape of the road ahead of the host vehicle 100. The means by which the road shape information acquisition unit 11 acquires the information on the road shape is not limited to the map database 31. For example, the road shape information acquisition unit 11 may acquire information on the shape of the road ahead of the host vehicle 100 detected by the periphery detection device 33.

[0019] The sidewall information acquisition unit 12 acquires information on the surrounding environment of the vehicle 100 (hereinafter referred to as "surrounding information") from the surroundings detection device 33, and acquires information on whether or not a sidewall exists on the road on which the vehicle 100 is traveling from the surroundings information. The sidewall information acquisition unit 12 acquires at least information on the presence or absence of a sidewall on the road ahead of the vehicle 100. The means by which the sidewall information acquisition unit 12 acquires the information on the presence or absence of a sidewall is not limited to the surroundings detection device 33. For example, if the map data in the map database 31 includes information on the sidewalls of the road, the sidewall information acquisition unit 12 may acquire, from the map database 31, information on the presence or absence of a sidewall on the road on which the vehicle 100 is traveling.

[0020] The brightness determination unit 13 determines whether the brightness around the host vehicle 100 is bright enough to require the implementation of support illumination (i.e., illumination of light that helps the driver of the host vehicle 100 recognize the shape of the road). In this embodiment, the brightness determination unit 13 performs this brightness determination based on the usage status of the headlights 21. Specifically, if the headlights 21 are on, the brightness determination unit 13 determines that the area around the host vehicle 100 is dark and the brightness is such that the implementation of support illumination is necessary, and if the headlights 21 are off, the brightness determination unit 13 determines that the area around the host vehicle 100 is bright and the brightness is such that the implementation of support illumination is unnecessary. The brightness determination method is not limited to this method. For example, the brightness determination unit 13 may determine whether the brightness around the host vehicle 100 is bright enough to require the implementation of support illumination based on the usage status of the parking lamps and fog lamps, the brightness around the host vehicle 100 measured with an illuminance meter, the brightness of an image of the area around the host vehicle 100 captured with an in-vehicle camera, etc.

[0021] The support illumination determination unit 14 determines whether to perform support illumination based on the determination results of the presence or absence of sidewalls on the road on which the host vehicle 100 is traveling, the shape of the road, and the brightness around the host vehicle 100. Specifically, the support illumination determination unit 14 determines to perform support illumination when it is determined that a sidewall exists on the road on which the host vehicle 100 is traveling, the road is curved in the horizontal or vertical direction, and the brightness around the host vehicle 100 is sufficient to require the implementation of support illumination. Any method may be used to determine whether the road is curved. For example, one method for determining whether the road is curved in the horizontal direction is to determine whether the radius of curvature of the road is less than 100 m. For example, one method for determining whether the road is curved in the vertical direction is to determine whether the change in gradient of the road is 1% or more.

[0022] Both horizontal and vertical curvatures may be taken into account when determining whether a road is curved. Roads with a curvature radius of 100 m or more and roads with a gradient change of 0.5% to less than 1% are determined not to be curved using the above determination method. However, by taking both horizontal and vertical curvatures into account, for example, if the curvature radius of a road is 100 m to 150 m and the gradient change of the road is 0.5% to less than 1%, the road may be determined to be curved. In other words, whether a road is curved may be determined using an evaluation function in which the curvature radius and gradient change of the road are each weighted.

[0023] Furthermore, the traveling speed of the vehicle 100 may be taken into consideration when determining whether the road is curved. As the traveling speed of the vehicle 100 increases, the influence of the curvature of the road becomes greater. Therefore, the faster the traveling speed of the vehicle 100, the more likely it is to determine that the road is curved by increasing the threshold value of the curvature radius for determining the lateral curvature of the road or decreasing the threshold value of the gradient change for determining the longitudinal curvature of the road.

[0024] When the support illumination determination unit 14 determines that support illumination should be performed, the support illumination control unit 15 controls the lighting device 20 to perform support illumination. In this embodiment, the support illumination control unit 15 controls the sublight 22 to perform support illumination, but as described above, the headlight 21 may also be used for support illumination.

[0025] Several specific examples of assistance illumination will be described. Here, as shown in FIG. 2, a situation is assumed in which the road on which the host vehicle 100 is traveling changes from a straight road to a curved road (a road that curves laterally), i.e., the host vehicle 100 enters the curved road from the straight road. The straight road has a straight sidewall 201, which is a straight sidewall, and the curved road has a curved sidewall 202, which is a curved sidewall that follows the curved road. Furthermore, the headlights 21 are turned on (FIG. 2 shows headlight light 101 emitted from the headlights 21), and the brightness determination unit 13 determines that the brightness around the host vehicle 100 is bright enough to require the implementation of assistance illumination. Thus, the situation in FIG. 2 is a situation in which the road on which the host vehicle 100 is traveling has sidewalls (the straight sidewall 201 and the curved sidewall 202), the road is curved, and the brightness around the host vehicle 100 is determined to be bright enough to require the implementation of assistance illumination. Therefore, the support irradiation determination unit 14 determines that support irradiation should be performed, and the support irradiation control unit 15 performs support irradiation.

[0026] FIG. 2 shows an example of assistance illumination in which a single bar-shaped (horizontal bar-shaped) illumination pattern 102 extending perpendicular to the traveling direction of the host vehicle 100 is illuminated onto the road surface ahead of the host vehicle 100. A portion of the illumination pattern 102 is illuminated onto a curved sidewall 202. When viewed from the host vehicle 100, the direction in which the illumination pattern 102 extends on the road surface is horizontal to the road surface, but the direction in which the illumination pattern 102 extends on the curved sidewall 202 appears to be tilted with respect to the road surface. Therefore, the driver of the host vehicle 100 can recognize the presence of the curved sidewall 202 from the position of the illumination pattern 102 that appears tilted. The illumination position of the illumination pattern 102 may be a fixed distance (e.g., 30 m) ahead of the host vehicle 100. If the illumination position of the illumination pattern 102 is set to a position at a fixed distance from the host vehicle 100, control of the illumination position by the driving assistance device 105 can be simplified.

[0027] There may be a plurality of bar-shaped irradiation patterns 102. In this case, as shown in FIG. 3 , the irradiation mode may be different between the irradiation pattern 102 irradiated onto the straight sidewall 201 and the irradiation pattern 102 irradiated onto the curved sidewall 202. In this case, it is preferable that the irradiation pattern 102 irradiated onto the curved sidewall 202 be more noticeable (higher visibility) than the irradiation pattern 102 irradiated onto the straight sidewall 201. Specifically, it is possible to make the width of the irradiation pattern 102 irradiated onto the curved sidewall 202 wider than the width of the irradiation pattern 102 irradiated onto the straight sidewall 201, make the interval between the irradiation patterns 102 irradiated onto the curved sidewall 202 narrower than the interval between the irradiation patterns 102 irradiated onto the straight sidewall 201, make the color tone of the irradiation pattern 102 irradiated onto the curved sidewall 202 brighter than the color tone of the irradiation pattern 102 irradiated onto the straight sidewall 201, etc.

[0028] The illumination mode of the bar-shaped illumination pattern 102 may be different between the portion illuminated on the road surface and the portion illuminated on the sidewall. For example, the color tone or thickness may be different between the portion illuminated on the road surface and the portion illuminated on the sidewall of the illumination pattern 102. This makes it easier to distinguish between the portion illuminated on the road surface and the portion illuminated on the sidewall of the illumination pattern 102, making it easier for the driver of the vehicle 100 to recognize the presence of the curved sidewall 202.

[0029] The width of the bar-shaped irradiation pattern 102 may be set to a width that reaches the very edge of the side wall when the road is straight. In this case, the irradiation pattern 102 reaches the curved side wall 202 but does not reach the straight side wall 201. Therefore, the driver can distinguish between the straight side wall 201 and the curved side wall 202 based on the presence or absence of the irradiation pattern 102, which appears to be tilted. However, since the irradiation pattern 102 that does not reach the straight side wall 201 has difficulty indicating a situation in which a straight road is curved in the vertical direction, it can be said that the irradiation pattern 102 is specialized for indicating the lateral curvature of the road.

[0030] The irradiation pattern 102 may be a broken or dotted line pattern instead of a solid line pattern (continuous line pattern). For example, the bar-shaped irradiation pattern 102 may be a pattern that is irradiated onto the sidewalls and their vicinity, but not onto the center of the road.

[0031] The irradiation pattern 102 may be a line (vertical bar) extending along the traveling direction of the host vehicle 100. Fig. 4 shows an example of assistance illumination in which a single line-shaped irradiation pattern 102 extending along the traveling direction of the host vehicle 100 is irradiated onto the road surface ahead of the host vehicle 100.

[0032] The irradiation pattern 102 may be a pattern formed by combining a bar-shaped pattern and a line-shaped pattern. Fig. 5 shows an example of assistance illumination in which a cross-shaped irradiation pattern 102 formed by combining one bar-shaped pattern and one line-shaped pattern is projected onto the road surface ahead of the vehicle 100. The irradiation pattern 102 may also be a pattern formed by combining one line-shaped pattern and multiple bar-shaped patterns intersecting the line-shaped pattern. The irradiation pattern 102 formed by combining a bar-shaped pattern and a line-shaped pattern is effective on spiral roads with long curves, such as highway interchanges.

[0033] As described above, the driving assistance device 10 according to the first embodiment can urge the driver to recognize the shape of the curved road by illuminating the sidewall of the road with the assistance illumination light. This can improve the driver's awareness of the road shape. As a result, the risk of the host vehicle 100 colliding with the sidewall can be reduced, contributing to safe driving.

[0034] 6 is a flowchart showing the operation of the driving assistance device 10 according to embodiment 1. The operation of the driving assistance device 10 will be described below with reference to the flowchart of FIG.

[0035] When the driving assistance device 10 is started and the vehicle 100 starts driving, the brightness determination unit 13 determines whether the brightness around the vehicle 100 is bright enough to require the implementation of assistance illumination based on the usage status of the headlights 21 (step S101).

[0036] The road shape information acquisition unit 11 compares the position of the vehicle 100 measured by the positioning device 32 with the map data in the map database 31 to identify the road on which the vehicle 100 is traveling, and acquires information on the shape of the road on which the vehicle 100 is traveling from the map database 31 (step S102).

[0037] The sidewall information acquisition unit 12 acquires information from the periphery detection device 33 as to whether or not a sidewall exists on the road on which the vehicle 100 is traveling (step S103).

[0038] The support illumination determination unit 14 determines whether or not the conditions for performing support illumination (support illumination performance conditions) are met based on the information acquired in steps S101 to S103 (step S104). Specifically, the support illumination determination unit 14 determines to perform support illumination when it is determined that a sidewall exists on the road on which the vehicle 100 is traveling, the road is curved in the horizontal or vertical direction, and the brightness around the vehicle 100 is sufficient to require the performance of support illumination.

[0039] If the support irradiation execution condition is satisfied (YES in step S104), the support irradiation control unit 15 controls the sublight 22 to execute support irradiation (step S105). If the support irradiation execution condition is not satisfied (NO in step S104), support irradiation is not executed.

[0040] Thereafter, the driving assistance device 10 checks whether the traveling of the host vehicle 100 has ended (step S106). If the traveling of the host vehicle 100 continues (NO in step S106), the process returns to step S101, and if the traveling of the host vehicle 100 has ended (YES in step S106), the operation of the driving assistance device 10 ends.

[0041] [Variations] The assistance illumination may be performed by illuminating a fan-shaped light that spreads in the horizontal direction (a certain height direction) but not in the vertical direction. In this case, as shown in Figs. 7 and 8, the illumination pattern 102 is not illuminated onto the road surface, and a linear illumination pattern 102 extending in the horizontal direction is illuminated onto the curved sidewall 202. Compared to when the illumination pattern 102 is illuminated onto the road surface as shown in Figs. 2 to 5, this can prevent the driver of the host vehicle 100 from feeling annoyed by the illumination pattern 102. However, it should be noted that when the illumination pattern 102 is not illuminated onto the road surface, the effect of making the driver recognize the boundary between the road surface and the sidewall is reduced.

[0042] Assist illumination may also be performed by illuminating the sidewall with a plurality of illumination patterns 102, as shown in Fig. 9 to Fig. 11. Fig. 9 shows an example in which the illumination pattern 102 is an arrow-shaped pattern, Fig. 10 shows an example in which the illumination pattern 102 is an L-shaped pattern, and Fig. 11 shows an example in which the illumination pattern 102 is a disk-shaped pattern. These illumination patterns 102 imitate road structures (for example, reflectors or LED lights installed on the sidewall) that facilitate recognition of the shape of the road, and are compatible with the sidewall, making it possible to prevent the illumination patterns 102 from causing discomfort to the driver of the vehicle 100.

[0043] The irradiation pattern 102 may be provided with an animation effect that changes over time, such as blinking, changing color, or changing position. The irradiation pattern 102 may also be a single dot-like pattern. The animation effect of the irradiation pattern 102 is preferably provided when the curvature of the road is small.

[0044] The mode of the irradiation pattern 102 may be changed depending on the shape of the road on which the vehicle 100 is traveling. For example, the higher the curvature of the road, the more noticeable the irradiation pattern 102 may be. Specifically, the higher the curvature of the road, the wider the width, the more bars, or the higher the density of the bar-shaped irradiation patterns 102 may be.

[0045] 12 to 15 show examples of assistance illumination suitable for indicating that a road is curved in the vertical direction. For example, when the vehicle 100 approaches a downhill slope, a plurality of arrow-shaped illumination patterns 102 arranged along an upwardly convex curve may be illuminated onto the sidewall, as shown in Figs. 12 and 13. Conversely, when the vehicle 100 approaches an uphill slope, a plurality of arrow-shaped illumination patterns 102 arranged along an upwardly convex curve may be illuminated onto the sidewall.

[0046] Furthermore, when the host vehicle 100 approaches a downhill slope, a plurality of downward arrow-shaped irradiation patterns 102 may be projected onto the sidewall, as shown in Figures 14 and 15. Conversely, when the host vehicle 100 approaches an uphill slope, a plurality of upward arrow-shaped irradiation patterns 102 may be projected onto the sidewall. The plurality of arrow-shaped irradiation patterns 102 may be projected at a position at a certain height from the road surface.

[0047] The irradiation position and manner of the irradiation pattern 102 may be changed according to the traveling speed of the host vehicle 100. For example, the irradiation position of the irradiation pattern 102 may be controlled so that the irradiation pattern 102 is irradiated at a position where the host vehicle 100 will arrive in three seconds. Furthermore, the manner of the irradiation pattern 102 may be controlled so that the irradiation pattern 102 becomes more noticeable as the traveling speed of the host vehicle 100 increases.

[0048] The irradiation position and manner of the irradiation pattern 102 may be changed taking into consideration both the shape of the road on which the vehicle 100 is traveling and the traveling speed of the vehicle 100.

[0049] <Embodiment 2> Fig. 16 is a diagram showing the configuration of a vehicle system 1 according to embodiment 2. The configuration of the vehicle system 1 in Fig. 16 is different from the configuration in Fig. 1 in that an image recognition device 34 is connected to the driving assistance device 10 and a recognition degree estimation unit 16 is added to the driving assistance device 10.

[0050] The image recognition device 34 analyzes images of the surroundings of the driving assistance device 10 captured by an onboard camera (not shown) of the vehicle 100, and recognizes the color tone (e.g., hue, saturation, brightness, etc.) of the road and sidewalls on which the vehicle 100 is traveling.

[0051] The recognition level estimation unit 16 acquires information on the color tone of the sidewalls and road surface of the road on which the vehicle 100 is traveling from the image recognition device 34, and estimates the driver's recognition of the road shape based on the difference in color tone between the sidewalls and the road surface. Normally, when the difference in color tone between the sidewalls and the road surface is small, it is difficult for the driver to recognize the road shape. Therefore, the recognition level estimation unit 16 estimates that the driver's recognition of the road shape is low when the difference in color tone between the sidewalls and the road surface is small, and estimates that the driver's recognition of the road shape is high when the difference in color tone between the sidewalls and the road surface is large.

[0052] In the second embodiment, the support illumination control unit 15 determines not to perform support illumination when the driver's recognition of the road shape estimated by the recognition estimation unit 16 is equal to or greater than a predetermined threshold.

[0053] The recognition level estimation unit 16 may calculate the average value of the color difference between the road surface and the sidewall in a predetermined range ahead of the host vehicle 100 as the color difference between the sidewall and the road surface. In this embodiment, the recognition level estimation unit 16 calculates the average value of the color difference between the road surface and the sidewall in a range that the host vehicle 100 will pass through between 2 and 3 seconds from now as the color difference between the sidewall and the road surface. In this case, if the distance that the host vehicle 100 will reach in 2 seconds is L2, the distance that the host vehicle 100 will reach in 3 seconds is L3, and L = L3 - L2, the color difference D between the road surface and the sidewall is calculated by the following formula. D=∫|Cdri(r)-Cdwi(r)| / L (r=L2~L3) In this formula, r is the distance from the vehicle 100, Cdri(r) is the color tone of the road surface at the distance r, and Cdwi(r) is the color tone of the sidewall at the distance r.

[0054] The range for calculating the average value of the color tone difference may be wider than the range from 2 seconds to 3 seconds later. Alternatively, the color tone difference may be calculated over a range wider than the range from 2 seconds to 3 seconds later, and a weighted average may be calculated by increasing the weight of the color tone difference in the range from 2 seconds to 3 seconds later as the color tone difference between the sidewall and the road surface.

[0055] The color parameter used to calculate the color difference may be one or more of the hue, saturation, and brightness parameters, or other parameters. For example, the color difference may be calculated from the contrast value between the road surface and the sidewall in an image of the surroundings of the vehicle 100.

[0056] Fig. 17 is a flowchart showing the operation of the driving assistance device 10 according to embodiment 2. The flowchart in Fig. 17 is obtained by adding steps S201 and S202 between steps S104 and S105 to the flowchart in Fig. 6.

[0057] Step S201 is performed when it is determined in step S104 that the conditions for performing assist irradiation (assist irradiation execution conditions) are met (YES in step S104). In step S201, the recognition estimation unit 16 calculates the difference in color tone between the sidewalls and the road surface from the information on the color tone of the sidewalls and the road surface of the road on which the host vehicle 100 is traveling, obtained from the image recognition device 34, and estimates the driver's recognition of the road shape.

[0058] Step S202 is performed after step S201. In step S202, the support irradiation determination unit 14 checks whether the degree of recognition estimated in step S201 is less than a predetermined threshold. If the degree of recognition is less than the threshold (YES in step S202), the support irradiation determination unit 14 determines that support irradiation should be performed, and support irradiation is performed in step S105. However, if the degree of recognition is equal to or greater than the threshold (NO in step S202), the support irradiation determination unit 14 determines that support irradiation is not necessary, and the process proceeds to step S106 without performing support irradiation.

[0059] According to the driving assistance device 10 of the second embodiment, unnecessary assistance illumination is not performed when the driver has a high degree of awareness of the road shape, which prevents the driver from feeling annoyed by the assistance illumination and contributes to reducing power consumption.

[0060] [Variations] In the second embodiment, an example is shown in which the recognition estimation unit 16 estimates the driver's recognition of the road shape based on the color difference between the side walls and the road surface of the road, but the method of estimating the recognition of the road shape is not limited to this.

[0061] The lane markings on the road are one of the means by which the driver recognizes the road shape. Therefore, the recognition level estimation unit 16 may estimate the driver's recognition level of the road shape based on the color difference between the road and the lane markings. The color difference between the road and the lane markings can be calculated, for example, by analyzing an image of the surroundings of the vehicle 100 captured by an on-board camera.

[0062] Furthermore, when the surroundings become dark, it becomes difficult for the driver to recognize the road shape. Therefore, the recognition degree estimation unit 16 may estimate the driver's recognition degree of the road shape based on the brightness around the vehicle 100. The brightness of the surroundings may be calculated by analyzing an image of the surroundings of the vehicle 100 captured by an on-board camera, or may be actually measured with an illuminance meter, for example.

[0063] Furthermore, if road structures (such as reflectors or LED lights installed on side walls) that help the driver recognize the road shape are installed, the driver can easily recognize the road shape. Therefore, the recognition degree estimation unit 16 may estimate the driver's recognition degree of the road shape based on the presence or absence of road structures. The presence or absence of road structures can be determined, for example, by analyzing images of the surroundings of the vehicle 100 captured by an on-board camera.

[0064] The awareness estimation unit 16 may estimate the driver's awareness of road shapes based on the driver's visual ability. The awareness estimation unit 16 may estimate the driver's visual ability using any method. For example, the awareness estimation unit 16 may use a driver monitoring system (DMS) to monitor the driver's operation of the vehicle 100, and may estimate that the driver's visual ability is low if the driver frequently makes erroneous operations or sudden driving operations (such as sudden steering or braking). The awareness estimation unit 16 may also use the DMS to detect the driver's psychological or physiological state, and may estimate that the driver's actual visual ability is reduced if the driver is highly fatigued, has a low level of alertness, or is looking around aimlessly. The driver may also be allowed to input information indicating his or her own visual ability (e.g., eyesight, presence or absence of cataracts, etc.) into the awareness estimation unit 16 in advance.

[0065] The recognition level estimation unit 16 may estimate the driver's recognition level of the road shape by combining two or more of the above methods.

[0066] <Third Embodiment> The configuration of the vehicle system 1 according to the third embodiment is the same as that of the second embodiment (FIG. 16). In the driving assistance device 10 according to the third embodiment, the assistance illumination control unit 15 changes the mode of assistance illumination according to the driver's awareness of the road shape estimated by the awareness estimation unit 16. Specifically, the assistance illumination control unit 15 performs assistance illumination in a more conspicuous mode (mode with high visibility) as the driver's awareness of the road shape decreases.

[0067] Fig. 18 is a flowchart showing the operation of the driving assistance device 10 according to embodiment 3. In the flowchart of Fig. 18, step S105 of Fig. 17 is replaced with steps S301 and S302.

[0068] Step S301 is performed when it is determined in step S202 that the driver's awareness of the road shape is equal to or greater than a threshold (NO in step S202). When the driver's awareness of the road shape is high, there is little need to provide support illumination in a conspicuous manner, so in step S301, the support illumination control unit 15 provides support illumination in a first manner that is a modest manner (a manner with low visibility). This prevents the driver from feeling annoyed by the support illumination.

[0069] Step S302 is performed when it is determined in step S202 that the driver's awareness of the road shape is less than the threshold (YES in step S202). When the driver's awareness of the road shape is low, there is a high need to provide support illumination in a conspicuous manner, so in step S302, the support illumination control unit 15 provides support illumination in the second manner, which is a conspicuous manner. This effectively improves the driver's awareness of the road shape.

[0070] For example, it is possible to make the size of the irradiation pattern in the second mode of assisted irradiation larger than the size of the irradiation pattern in the first mode of assisted irradiation, or to make the color tone of the irradiation pattern in the second mode of assisted irradiation brighter than the color tone of the irradiation pattern in the second mode of assisted irradiation, etc.

[0071] The driving assistance device 10 according to the third embodiment can provide appropriate assistance illumination according to the driver's awareness of the road shape.

[0072] [Variations] In the third embodiment, the support illumination control unit 15 switches between two types of support illumination depending on the driver's awareness of the road shape, but the awareness may be subdivided by setting two or more thresholds for the awareness, and the support illumination control unit 15 may switch between three or more types of support illumination depending on the level of awareness. Alternatively, the support illumination control unit 15 may change the mode of support illumination continuously or in multiple stages depending on the level of awareness.

[0073] For example, when the driver has a low level of awareness of the road shape, support illumination with an animation effect may be performed. Also, the lower the driver's awareness, the greater the speed or amount of change in the animation may be.

[0074] When the mode of the assist irradiation is changed continuously, for example, the size of the irradiation pattern may be changed continuously, or the amount of change in the animation may be changed continuously.

[0075] <Hardware configuration example> 19 and 20 are diagrams illustrating examples of the hardware configuration of the driving assistance device 10. The functions of the components of the driving assistance device 10 illustrated in FIG. 1 are realized, for example, by a processing circuit 50 illustrated in FIG. 19. That is, the driving assistance device 10 acquires information about the shape of the road on which the host vehicle 100 is traveling, acquires information about whether a sidewall is present on the road, determines whether the brightness around the host vehicle 100 is bright enough to require the implementation of assistance illumination, which is illumination of light that helps the driver of the host vehicle 100 recognize the shape of the road, determines whether assistance illumination is to be implemented based on the determination results of the presence or absence of a sidewall on the road, the shape of the road, and the brightness around the host vehicle 100, and, when it is determined that assistance illumination is to be implemented, controls the lighting devices 20 of the host vehicle 100 to implement assistance illumination. When it is determined that a sidewall is present on the road, the road is curved in the horizontal or vertical direction, and the brightness around the host vehicle 100 is bright enough to require the implementation of assistance illumination, the processing circuit 50 determines to implement assistance illumination and implements assistance illumination by irradiating at least a portion of light onto the sidewall of the road.

[0076] The processing circuit 50 may be dedicated hardware, or may be configured using a processor (also called a central processing unit (CPU), processing device, arithmetic unit, microprocessor, microcomputer, or DSP (Digital Signal Processor)) that executes a program stored in memory.

[0077] When the processing circuit 50 is dedicated hardware, the processing circuit 50 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. Each function of the components of the driving assistance device 10 may be realized by a separate processing circuit, or these functions may be collectively realized by a single processing circuit.

[0078] FIG. 20 shows an example of a hardware configuration of the driving assistance device 10 in a case where the processing circuit 50 is configured using a processor 51 that executes a program. In this case, the functions of the components of the driving assistance device 10 are realized by software or the like (software, firmware, or a combination of software and firmware). The software or the like is written as a program and stored in the memory 52. The processor 51 realizes the functions of each part by reading and executing the program stored in the memory 52. That is, the driving assistance device 10 includes the memory 52 for storing a program that, when executed by the processor 51, results in the following execution: a process of acquiring information on the shape of the road on which the host vehicle 100 is traveling; a process of acquiring information on whether or not a sidewall is present on the road; a process of determining whether or not the brightness around the host vehicle 100 is bright enough to require the implementation of assistance illumination, which is illumination of light that helps the driver of the host vehicle 100 recognize the shape of the road; a process of determining whether or not to implement assistance illumination based on the determination results of the presence or absence of a sidewall on the road, the shape of the road, and the brightness around the host vehicle 100; and a process of controlling the lighting devices 20 of the host vehicle 100 to implement assistance illumination when it is determined that assistance illumination should be performed. The processor 51 that executes this program determines to perform support illumination when it is determined that there is a sidewall on the road, that the road is curved in the horizontal or vertical direction, and that the brightness around the vehicle 100 is bright enough to require the implementation of support illumination, and performs support illumination by illuminating at least a portion of the light onto the sidewall of the road. In other words, this program can be said to cause a computer to execute the procedures and methods of operation of the components of the driving assistance device 10.

[0079] Here, the memory 52 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), HDD (Hard Disk Drive), magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disc) and its drive device, or any other storage medium that will be used in the future.

[0080] The above describes a configuration in which the functions of the components of the driving assistance device 10 are realized either by hardware or software, etc. However, the present invention is not limited to this, and the configuration may be such that some of the components of the driving assistance device 10 are realized by dedicated hardware and other components are realized by software, etc. For example, it is possible to realize the functions of some of the components by the processing circuit 50 as dedicated hardware, and to realize the functions of other components by the processing circuit 50 as the processor 51 reading and executing a program stored in the memory 52.

[0081] As described above, the driving assistance device 10 can realize the above-described functions by hardware, software, or a combination of these.

[0082] It is possible to freely combine the embodiments, and to modify or omit the embodiments as appropriate.

[0083] The above description is illustrative in all respects, and it is understood that countless variations not illustrated can be envisioned. [Explanation of symbols]

[0084] 1 Vehicle system, 10 Driving assistance device, 11 Road shape information acquisition unit, 12 Side wall information acquisition unit, 13 Brightness determination unit, 14 Assist illumination judgment unit, 15 Assist illumination control unit, 16 Recognition estimation unit, 20 Lighting device, 21 Headlight, 22 Sublight, 31 Map database, 32 Positioning device, 33 Periphery detection device, 34 Image recognition device, 50 Processing circuit, 51 Processor, 52 Memory, 100 Vehicle, 101 Headlight light, 102 Irradiation pattern, 201 Straight side wall, 202 Curved side wall.

Claims

1. a road shape information acquisition unit that acquires information about the shape of a road on which the host vehicle is traveling; a sidewall information acquisition unit that acquires information on whether or not a sidewall exists on the road; a brightness determination unit that determines whether or not the brightness around the host vehicle is bright enough to require the implementation of assistive illumination, which is illumination of light that encourages the driver of the host vehicle to recognize the shape of the road; an assist illumination determination unit that determines whether or not to perform the assist illumination based on the determination results of the presence or absence of the sidewall of the road, the shape of the road, and the brightness around the vehicle; a support illumination control unit that controls the lighting devices of the host vehicle to perform the support illumination when it is determined that the support illumination is to be performed; Equipped with the support illumination determination unit determines to perform the support illumination when it is determined that the side wall exists on the road, the road is curved in a horizontal direction or a vertical direction, and the brightness around the vehicle is bright enough to require the performance of the support illumination; the support illumination control unit performs the support illumination by irradiating at least a portion of the light onto the side wall of the road. Driving assistance device.

2. a recognition level estimation unit that estimates the driver's recognition level of the road shape, The assist irradiation determination unit determines not to perform the assist irradiation when the degree of recognition is less than a predetermined threshold. The driving assistance device according to claim 1 .

3. the recognition degree estimation unit estimates the recognition degree based on a difference in color tone between the sidewall and the road surface of the road; The driving assistance device according to claim 2 .

4. the recognition degree estimation unit estimates the recognition degree based on the visual ability of the driver; The driving assistance device according to claim 2 .

5. the recognition degree estimation unit estimates the recognition degree based on a difference in color tone between the road marking and the road surface; The driving assistance device according to claim 2 .

6. the recognition degree estimation unit estimates the recognition degree based on whether or not a road structure that promotes recognition of the shape of the road exists on the road; The driving assistance device according to claim 2 .

7. a recognition level estimation unit that estimates the driver's recognition level of the road shape, the assist irradiation control unit performs the assist irradiation in a more noticeable manner as the recognition level is lower; The driving assistance device according to claim 1 .

8. the recognition degree estimation unit estimates the recognition degree based on a difference in color tone between the sidewall and the road surface of the road; The driving assistance device according to claim 7.

9. the recognition degree estimation unit estimates the recognition degree based on the visual ability of the driver; The driving assistance device according to claim 7.

10. the recognition degree estimation unit estimates the recognition degree based on a difference in color tone between the road marking and the road surface; The driving assistance device according to claim 7.

11. the recognition degree estimation unit estimates the recognition degree based on whether or not a road structure that promotes recognition of the shape of the road exists on the road; The driving assistance device according to claim 7.

12. The assisting illumination is performed by illuminating the sidewall or road surface of the road with a point or line illumination pattern; The driving assistance device according to claim 1 .

13. the point-shaped irradiation pattern is irradiated onto the side wall of the road, and the linear irradiation pattern is irradiated onto the side wall of the road or onto the side wall of the road and the road surface; The driving assistance device according to claim 12.

14. The illumination pattern is a pattern that simulates road structures to promote recognition of the shape of the road. The driving assistance device according to claim 12.

15. the support illumination control unit changes the manner of the point-like illumination pattern illuminated onto the side wall of the road over time. The driving assistance device according to claim 12.

16. the support illumination control unit changes the mode of the support illumination according to the shape of the road. The driving assistance device according to claim 1 .

17. the support illumination control unit changes the mode of the support illumination in accordance with a traveling speed of the host vehicle. The driving assistance device according to claim 1 .

18. a road shape information acquisition unit of the driving assistance device acquires information on the shape of the road on which the vehicle is traveling; a sidewall information acquisition unit of the driving assistance device acquires information on whether a sidewall exists on the road; a brightness determination unit of the driving assistance device determines whether or not the brightness around the vehicle is bright enough to require the implementation of assistance illumination, which is illumination of light that prompts the driver of the vehicle to recognize the shape of the road; an assist illumination determination unit of the driving assist device determines whether to perform the assist illumination based on a determination result of the presence or absence of the side wall of the road, the shape of the road, and the brightness around the vehicle; When it is determined that the support illumination is to be performed, an support illumination control unit of the driving support device controls a lighting device of the host vehicle to perform the support illumination, the support illumination determination unit determines to perform the support illumination when it is determined that the side wall exists on the road, the road is curved in a horizontal direction or a vertical direction, and the brightness around the vehicle is bright enough to require the performance of the support illumination; the support illumination control unit performs the support illumination by irradiating at least a portion of the light onto the side wall of the road. Driving assistance methods.

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