Wrong-way driving determination device and wrong-way driving determination method

Abstract

To provide a wrong-way driving determination device that is capable of accurately determining whether or not a vehicle is driving in the wrong direction.SOLUTION: An image analysis unit 2 acquires a captured image of a road surface of a road being traveled by a vehicle captured by a camera 1 that images a front side of the vehicle, and analyzes at least one of a color and a luminance of the captured image. When the vehicle is traveling on a road with a wrong-way driving warning structure provided on the road surface, a wrong-way driving determination unit 4 determines that the vehicle is traveling on the road in the wrong direction based on a result of analysis by the image analysis unit 2 when the captured image satisfies at least a condition of including a color or a luminance specific to a surface that can be only captured when the vehicle is running on the road in the wrong direction in at least one step of a plurality of steps included in the wrong-way driving warning structure and formed at predetermined intervals in the direction of wrong-way driving of a vehicle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a reverse running determination device and a reverse running determination method.

Background Art

[0002] Traffic accidents may occur due to so-called reverse running, in which a vehicle erroneously enters the oncoming lane and travels in the oncoming lane. Patent Documents 1 and 2 describe structures on the road that enable a driver to recognize reverse running of the vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] With only the structures on the road as described in Patent Documents 1 and 2, a driver may not recognize that the vehicle is running in reverse. In order to stop reverse running, it is required to accurately determine whether the vehicle is running in reverse.

[0005] An object of the present invention is to provide a reverse running determination device and a reverse running determination method that can accurately determine whether a vehicle is running in reverse.

Means for Solving the Problems

[0006] The present invention provides a reverse running determination device including an image analysis unit that acquires a captured image of a road surface on which a vehicle travels, which is captured by a camera that captures the front of the vehicle, and analyzes at least one of the color and brightness of the captured image, and a reverse running determination unit that, when the vehicle is traveling on a road provided with a reverse running warning structure on the road surface, determines that the vehicle is running in reverse on the road based on the analysis result by the image analysis unit when the captured image satisfies at least a first condition that the captured image includes a color or brightness specific to a surface that is captured only when the vehicle is running in reverse on the road and that is formed at a predetermined interval in the direction in which the vehicle travels on at least one of a plurality of steps of the reverse running warning structure.

[0007] The present invention provides a reverse running determination method in which a camera that captures the front of a vehicle captures the road surface on which the vehicle travels, an image analysis unit analyzes at least one of the color and brightness of the captured image by the camera, and when the vehicle is traveling on a road provided with a reverse running warning structure on the road surface, a reverse running determination unit determines whether or not the captured image satisfies a condition that the captured image includes a color or brightness specific to a surface that is captured only when the vehicle is running in reverse on the road and that is formed at a predetermined interval in the direction in which the vehicle travels on at least one of a plurality of steps of the reverse running warning structure, and if the condition is satisfied, determines that the vehicle is running in reverse on the road.

Advantages of the Invention

[0008] According to the reverse running determination device and the reverse running determination method of the present invention, it is possible to accurately determine whether a vehicle is running in reverse.

Brief Description of the Drawings

[0009]

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DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a reverse running determination device and a reverse running determination method according to an embodiment will be described with reference to the accompanying drawings. FIG. 1 shows a reverse running determination device 100 according to an embodiment. The reverse running determination device 100 includes a camera 1, an image analysis unit 2, an acceleration sensor 3, a reverse running determination unit 4, a warning unit 5, and an instruction unit 6.

[0011] The driving control unit 11, the drive source 12, and the brake 13 surrounded by the dashed line are components provided in the vehicle on which the reverse running determination device 100 is mounted. The drive source 12 is an engine, a motor, or a combination of an engine and a motor. The driving control unit 11 controls the drive source 12 when accelerating the vehicle or running at a predetermined speed, and controls the brake 13 when decelerating or stopping the vehicle.

[0012] The reverse running determination device 100 may be configured not to include the warning unit 5 and the instruction unit 6. By including at least one of the warning unit 5 and the instruction unit 6, the reverse running determination device 100 also functions as a reverse running prevention device.

[0013] The reverse running determination device 100 may be built into a drive recorder. When the reverse running determination device 100 is built into the drive recorder, the camera provided in the drive recorder for photographing the front of the vehicle can be used as the camera 1. A collision prevention camera provided in the vehicle may be used as the camera 1. That is, the camera 1 may be configured outside the reverse running determination device 100. The components other than the camera 1 in the reverse running determination device 100 may be built into a car navigation device. In this case, the camera 1 is connected to the car navigation device.

[0014] When the reverse travel determination device 100 is built in the drive recorder, the acceleration sensor included in the drive recorder may be used as the acceleration sensor 3. When the reverse travel determination device 100 is built in the car navigation device, the acceleration sensor included in the car navigation device may be used as the acceleration sensor 3. Therefore, the acceleration sensor 3 may be configured as an external component of the reverse travel determination device 100.

[0015] The reverse travel determination device 100 only needs to be configured as an in-vehicle device, and may be provided as a dedicated in-vehicle device in the vehicle, or may be built in any in-vehicle device such as a drive recorder or a car navigation device.

[0016] In FIG. 1, at least a part of the image analysis unit 2, the reverse travel determination unit 4, the warning unit 5 (excluding the speaker 54 and the display unit 58 described later), and the instruction unit 6 may be configured by a central processing unit (microprocessor) of a microcomputer.

[0017] As shown in FIG. 2, a reverse travel warning structure 30 is provided on the road surface near the exit of the deceleration lane 23 for leaving the travel lane 21 of the highway 20 and heading for an interchange, a service area, or a parking area. The highway may be either a national expressway or an expressway for automobiles. FIG. 2 is an example of providing the reverse travel warning structure 30 on the road surface of a one-way road. The reverse travel warning structure 30 may be provided on the road surface near the exit of a one-way road on a general road, and the road on which the reverse travel warning structure 30 is provided is not limited.

[0018] In FIG. 2, vehicles 61 and 62 are traveling on the travel lane 21 and the overtaking lane 22 respectively, and vehicle 63 is about to enter the deceleration lane 23 from the travel lane 21. Vehicle 63 is a vehicle traveling forward in the correct direction in the deceleration lane 23. Vehicle 40 is about to enter the deceleration lane 23 from the exit of the deceleration lane 23 by mistake, and is about to become a reverse travel vehicle traveling in the oncoming lane. Hereinafter, vehicle 40 will be referred to as reverse travel vehicle 40.

[0019] Using FIGS. 3 to 9, a preferred configuration example of the reverse travel warning structure 30 will be described in detail. In the reverse travel warning structure 30 shown in FIGS. 3 and 4, a plurality of steps are provided by forming recesses in the road surface. As shown in FIG. 4, the reverse travel warning structure 30 has a plurality of sets each including a flat surface 31 at the same height as the road surface, an inclined surface 32 that slopes downward from the end of the flat surface 31, and a rising surface 33 that rises from the end of the inclined surface 32 to the same height as the road surface. These plurality of sets are provided in the direction in which a normal vehicle such as the reverse traveling vehicle 40 or the vehicle 63 that is not reverse traveling travels on the road. The height from the lower end to the upper end of the rising surface 33 forms a step. The rising surface 33 is formed, for example, every 500 mm.

[0020] As shown in FIG. 5, although the diameters of the tires vary depending on the vehicle, assuming that the diameter of the tire 40T of the reverse traveling vehicle 40 is 620 mm by averaging the diameters of various vehicles. In order for the driver of the reverse traveling vehicle 40 to feel the impact caused by the reverse traveling vehicle 40 traveling on the reverse travel warning structure 30, the tire 40T needs to overcome a step of about 20 mm. The step between the roadway and the sidewalk is generally about 20 mm. As shown in FIG. 5, since the tire 40T sinks into the inclined surface 32, in order for the tire 40T to overcome a step of about 20 mm, the lowest position of the inclined surface 32 needs to be about 50 mm from the road surface. That is, the depth of the recess needs to be about 50 mm.

[0021] In FIG. 3, it is assumed that the camera 1 is attached inside the reverse traveling vehicle 40 at a height of 1400 mm from the road surface. As shown in FIG. 4, the height from the lower end to the upper end of the rising surface 33, which is the depth of the recess, is 50 mm for the reasons described above. A position 25 mm below the vertical direction from the road surface at the center of the rising surface 33 located 10000 mm ahead in the horizontal direction from the camera 1 is defined as a reference position P0. A straight line connecting the camera 1 and the reference position P0 is defined as a straight line L0.

[0022] The straight line perpendicular to the straight line L0 at the reference position P0 has an angle of 8 degrees with respect to the vertical straight line. The rising surface 33 located 10,000 mm ahead from the camera 1 is inclined at 8 degrees in the traveling direction of the reverse traveling vehicle 40 with respect to the surface perpendicular to the traveling direction of the reverse traveling vehicle 40.

[0023] The reverse traveling warning structure 30 has five rising surfaces 33 at intervals of 500 mm on the front side of the rising surface 33 at the reference position P0 and five rising surfaces 33 at intervals of 500 mm on the rear side. Thus, the reverse traveling warning structure 30 has eleven rising surfaces 33. The initial position P1 is set at a position 25 mm below the vertical direction from the road surface at the center of the height of 50 mm of the first rising surface 33. The straight line connecting the camera 1 and the initial position P1 is defined as the straight line L1. The final position P2 is set at a position 25 mm below the vertical direction from the road surface at the center of the height of 50 mm of the last rising surface 33. The straight line connecting the camera 1 and the final position P2 is defined as the straight line L2.

[0024] The straight line perpendicular to the straight line L1 at the initial position P1 has an angle of 11 degrees with respect to the vertical straight line, and the first rising surface 33 is inclined at 11 degrees in the traveling direction of the reverse traveling vehicle 40 with respect to the surface perpendicular to the traveling direction of the reverse traveling vehicle 40. The straight line perpendicular to the straight line L2 at the final position P2 has an angle of 6 degrees with respect to the vertical straight line, and the last rising surface 33 is inclined at 6 degrees in the traveling direction of the reverse traveling vehicle 40 with respect to the surface perpendicular to the traveling direction of the reverse traveling vehicle 40.

[0025] As the distance in the direction along the road surface, the first inclined surface 32 is 268 mm, the inclined surface 32 connecting to the rising surface 33 located 10,000 mm ahead from the camera 1 is 354 mm, and the last inclined surface 32 is 441 mm. The eleven inclined surfaces 32 gradually become gentler in angle from the first inclined surface 32 to the last inclined surface 32, and the distance of the inclined surfaces 32 gradually becomes longer from the first inclined surface 32 to the last inclined surface 32. Along with this, the distance of the flat surfaces 31 gradually becomes shorter from the flat surface 31 between the first rising surface 33 and the second inclined surface 32 to the flat surface 31 immediately before the last inclined surface 32.

[0026] When the camera 1 photographs the entire reverse running warning structure 30, the angles of the lines of sight to each rising surface 33 from the first rising surface 33 closest to the reverse running vehicle 40 to the last rising surface 33 are different. When the camera 1 photographs the reverse running warning structure 30 from a certain viewpoint, the angles of the respective inclined surfaces 32 are individually set so that the flat surface 31 connected to the inclined surface 32 immediately before each rising surface 33 does not become a blind spot for each rising surface 33. Preferably, when the camera 1 photographs the reverse running warning structure 30 from a certain viewpoint, the angles of the respective inclined surfaces 32 are set so as to be orthogonal to the line of sight. When the reverse running warning structure 30 is configured as described above, it is possible to facilitate the camera 1 in photographing all the rising surfaces 33. When the camera 1 photographs the reverse running warning structure 30 from a certain viewpoint, all the rising surfaces 33 will be photographed and recognized almost evenly.

[0027] Also, from the first rising surface 33 to the last rising surface 33, it is possible to reduce the difference in the area of the rising surface 33 on the photographed image due to the difference in the distance between the camera 1 and the rising surface 33. Therefore, when the image analysis unit 2 analyzes the photographed image as described later, the photographed image can be analyzed without considering the difference in the distance between the camera 1 and each rising surface 33.

[0028] The reverse running warning structure 30 shown in FIGS. 3 and 4 is a preferred configuration example of the reverse running warning structure 30, and the reverse running warning structure 30 is not limited to the configuration shown in FIGS. 3 and 4. As shown in FIG. 6, a plurality of steps may be provided by forming convex portions instead of concave portions on the road surface. The convex portion has a rising surface 34 that rises from the road surface at an angle of, for example, 8 degrees, and an inclined surface 35 that inclines from the top of the rising surface 34 to the road surface. The convex portion has a height of 20 mm.

[0029] When the reverse running warning structure 30 is formed by a plurality of convex portions arranged at a predetermined interval in the traveling direction of the reverse running vehicle 40 or a normal vehicle that is not running in reverse, the angles of the rising surfaces 34 may all be a common, for example, 8 degrees.

[0030] As shown in FIGS. 3 to 5, when a step is formed by a recess, during reverse travel, the tire collides with the step formed by the rising surface 33 and then climbs over the step, resulting in a large impact. In contrast, during forward travel, the tire moves from the flat surface 31 to the inclined surface 32, so the impact is significantly smaller compared to reverse travel. Similarly, even when a step is formed by a protrusion as shown in FIG. 6, during reverse travel, the tire collides with the step formed by the rising surface 34 and then climbs over the step, resulting in a large impact. In contrast, during forward travel, although the tire climbs over the inclined surface 35, it does not collide with the step, so the impact is significantly smaller compared to when running.

[0031] The reverse travel warning structure 30 preferably has a step formed by a recess rather than a step formed by a protrusion. This is because a vehicle traveling forward experiences less impact when traveling on the reverse travel warning structure 30 having a step formed by a recess than when traveling on the reverse travel warning structure 30 having a step formed by a protrusion.

[0032] The rising surfaces 33 and 34 are the surfaces that are photographed only when the reverse traveling vehicle 40 is traveling in reverse on the deceleration lane 23. Even if a vehicle 63 traveling forward on the deceleration lane 23 is equipped with the reverse travel determination device 100 and the camera 1 photographs the road surface including the reverse travel warning structure 30, the rising surface 33 or 34 cannot be photographed.

[0033] When it is difficult to form the reverse travel warning structure 30 having the recess shown in FIGS. 3 and 4 or the protrusion shown in FIG. 6 with asphalt, the reverse travel warning structure 30 may be formed of hard rubber or the like and embedded in the road surface. When the reverse travel warning structure 30 is formed of hard rubber or the like, it can be mass-produced by molding.

[0034] In FIGS. 3 and 4, taking 20 mm as the step for the driver of the reverse vehicle 40 to feel an impact, and setting the depth of the concave portion to 50 mm for the tire 40T to cross the 20 mm step is just an example. In FIG. 6, setting the height of the convex portion to 20 mm is just an example. The depth of the concave portion is not limited to 50 mm, and the height of the convex portion is not limited to 20 mm.

[0035] The configuration of the reverse warning structure 30 will be further described in detail with reference to FIGS. 7 to 9. Here, the reverse warning structure 30 shown in FIGS. 3 and 4 having the rising surface 33 is taken as an example. The detailed configuration of the reverse warning structure 30 shown in FIGS. 7 to 9 is the same as that of the reverse warning structure 30 having the rising surface 34 shown in FIG. 6.

[0036] The plurality of rising surfaces 33 in the reverse warning structure 30 shall be referred to as rising surfaces 33a to 33k in the order from the closest to the reverse vehicle 40. FIG. 7 shows a first example of the color scheme applied to the rising surface 33 in the reverse warning structure 30. In the first example, on the rising surface 33a, for example, a yellow color portion 33Y and a black color portion 33B are provided in this order from the left side to the right side in the width direction of the deceleration lane 23. On the rising surface 33b, contrary to the rising surface 33a, a black color portion 33B and a yellow color portion 33Y are provided in this order from the left side to the right side in the width direction of the deceleration lane 23. After the rising surface 33c, the same color scheme as that of the rising surfaces 33a and 33b is repeated.

[0037] FIG. 8 shows a second example of the color scheme applied to the rising surface 33 in the reverse warning structure 30. In the second example, the rising surface 33a is a black color portion 33B, the rising surface 33b is a yellow color portion 33Y, and after the rising surface 33c, the black color portion 33B and the yellow color portion 33Y are alternately repeated in the same manner as the rising surfaces 33a and 33b. It is also possible that the rising surface 33a is a yellow color portion 33Y, the rising surface 33b is a black color portion 33B, and after the rising surface 33c, the yellow color portion 33Y and the black color portion 33B are alternately repeated.

[0038] FIG. 9 shows a third example of the color scheme applied to the rising surface 33 in the reverse running warning structure 30. In the third example, the rising surface 33a is a black color portion 33B. In the rising surface 33b, a yellow color portion 33Y is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. In the rising surface 33c, a yellow color portion 33Y wider than the yellow color portion 33Y of the rising surface 33b is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. In the rising surface 33d, a yellow color portion 33Y wider than the yellow color portion 33Y of the rising surface 33c is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof.

[0039] In the rising surface 33e, a yellow color portion 33Y wider than the yellow color portion 33Y of the rising surface 33d is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. In the rising surface 33f, a yellow color portion 33Y wider than the yellow color portion 33Y of the rising surface 33e is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. In the rising surface 33g, a yellow color portion 33Y narrower than the yellow color portion 33Y of the rising surface 33f is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. The width of the yellow color portion 33Y in the rising surface 33g is the same as the width of the yellow color portion 33Y in the rising surface 33e.

[0040] In the rising surface 33h, a yellow color portion 33Y narrower than the yellow color portion 33Y of the rising surface 33g is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. The width of the yellow color portion 33Y in the rising surface 33h is the same as the width of the yellow color portion 33Y in the rising surface 33d. In the rising surface 33i, a yellow color portion 33Y narrower than the yellow color portion 33Y of the rising surface 33h is provided at the center in the width direction, and black color portions 33B are provided on both sides thereof. The width of the yellow color portion 33Y in the rising surface 33i is the same as the width of the yellow color portion 33Y in the rising surface 33c.

[0041] On the rising surface 33j, a yellow color-matched portion 33Y that is narrower in width than the yellow color-matched portion 33Y of the rising surface 33i is provided at the center in the width direction, and black color-matched portions 33B are provided on both its left and right sides. The width of the yellow color-matched portion 33Y on the rising surface 33j is the same as the width of the yellow color-matched portion 33Y on the rising surface 33b. The rising surface 33k is a black color-matched portion 33B. In the third example, the entire yellow color-matched portion 33Y from the rising surface 33b to the rising surface 33j forms a hexagonal shape (pattern).

[0042] In FIGS. 7 to 9, the black color-matched portion 33B may be the color of asphalt (or hard rubber) itself, or may be colored black using paint or the like. The yellow color-matched portion 33Y is colored yellow using paint or the like. Since the combination of the yellow color-matched portion 33Y and the black color-matched portion 33B is a typical warning color, it is preferable to use the combination of the yellow color-matched portion 33Y and the black color-matched portion 33B. However, the reverse-travel warning structure 30 is not limited to including the yellow color-matched portion 33Y on the rising surface 33.

[0043] In JIS safety colors, which are the standards defined by the Japanese Industrial Standards (JIS), red represents fire prevention, prohibition, stop, high danger, orange-red represents danger, navigation and aviation security facilities, and yellow represents caution and warning. Therefore, instead of the yellow color-matched portion 33Y, a red or orange color-matched portion may be used. The rising surface 33 needs to be conspicuous to the driver of the reverse-travel vehicle 40, and a yellow-green color-matched portion may also be used as another color.

[0044] Instead of using the yellow color-matched portion 33Y colored yellow on the rising surface 33 using paint or the like, light-emitting diodes (LEDs) may be embedded in the rising surface 33 to emit yellow light. The same applies to color-matched portions of other colors, and they may be made to emit light in a predetermined color by LEDs. Considering the cost of the reverse-travel warning structure 30, it is better to color it in a predetermined color using paint or the like, or to make the color of the material itself the predetermined color.

[0045] The reverse driving warning structure 30 may have at least the following configuration. The reverse driving warning structure 30 includes a plurality of steps formed at a predetermined interval in the direction in which the vehicle travels on the road. Each rising surface among the plurality of steps includes a rising surface that cannot be photographed by a camera mounted on a vehicle driving forward in the correct direction on the road and can be photographed by a camera mounted on a vehicle driving in reverse on the road. A specific color is applied to the rising surface of at least one of the plurality of steps.

[0046] It is preferable that a pattern formed by a specific color is applied to the rising surface of at least one step. It is more preferable that patterns formed by specific colors are applied to the rising surfaces of two or more steps.

[0047] Each rising surface 33 among the plurality of steps is slightly inclined in the direction in which the reverse vehicle 40 travels with respect to the surface orthogonal to the direction in which the reverse vehicle 40 travels. It is preferable that the degree of inclination of the rising surface 33 gradually becomes gentler from the rising surface 33a closest to the reverse vehicle 40 to the rising surface 33k farthest from the reverse vehicle 40. That is, it is preferable that the plurality of rising surfaces 33 form angles such that they approach the surface orthogonal to the direction in which the reverse vehicle 40 travels in order from the rising surface 33a closest to the reverse vehicle 40 to the rising surface 33k farthest from the reverse vehicle 40.

[0048] In FIG. 2, when the reverse vehicle 40 approaches the reverse driving warning structure 30, the camera 1 photographs the plurality of rising surfaces 33. The camera 1 preferably photographs all the rising surfaces 33 at once, but may photograph only some of the rising surfaces 33 among the plurality of rising surfaces 33. That is, it is preferable that one frame of the photographed image includes all the rising surfaces 33, but depending on the length of the reverse driving warning structure 30, one frame of the photographed image may include only some of the rising surfaces 33. When one frame of the photographed image includes only some of the rising surfaces 33, the rising surfaces 33 included in the frame move in order as the frame progresses.

[0049] Since the deceleration lane 23 is often on a downhill slope, when viewed from the oncoming vehicle 40, the area near the exit of the deceleration lane 23 may be an uphill slope. In such a case, the camera 1 can easily capture all the rising surfaces 33 at once.

[0050] The driver of the oncoming vehicle 40 may notice that they are driving in reverse by recognizing the color scheme of the rising surface 33 of the reverse driving warning structure 30. Even if the driver does not notice their own reverse driving, the reverse driving determination device 100 determines that the oncoming vehicle 40 is in a reverse driving state as described later and warns the driver.

[0051] In FIG. 1, the image analysis unit 2 acquires and analyzes the captured image supplied from the camera 1. The image analysis unit 2 analyzes the color of each pixel in each frame. Assuming that the first example of the color scheme shown in FIG. 7 is used, a certain frame of the captured image supplied from the camera 1 to the image analysis unit 2 becomes a frame 1F as shown in FIG. 10. The image analysis unit 2 supplies the reverse driving determination unit 4 with analysis data in which the position information of the pixels and the color identification value indicating the color analyzed for each pixel are associated with each other in the frame 1F and other each frame. The analysis data may have the color identification values associated for each block composed of a plurality of pixels.

[0052] The color identification value may be a value for specifying a color based on the ratio of the R signal, G signal, and B signal of the RGB signals constituting the captured image, or may be a value obtained by converting each value of the R signal, G signal, and B signal into the L * a * b * value of the color space of L * a * b * value. The format of the color identification value is arbitrary.

[0053] FIG. 11 shows a first configuration example of the reverse running determination unit 4. The reverse running determination unit 4 includes a specific color presence / absence determination unit 41, a specific color setting unit 42, and a specific vibration presence / absence determination unit 43. In the specific color setting unit 42, a color identification value indicating the color of the yellow color portion 33Y is set as the specific color. If the analysis data of each frame includes a color identification value within a predetermined range of color identification values centered on the color identification value set in the specific color setting unit 42, the specific color presence / absence determination unit 41 determines that the camera 1 is photographing the rising surface 33 of the reverse running warning structure 30, that is, the vehicle is in a reverse running state.

[0054] To prevent misjudgment, if the analysis data of each frame includes a color identification value within a predetermined range of color identification values centered on the color identification value set in the specific color setting unit 42 and includes a predetermined number of pixels or more of the color identification value, the specific color presence / absence determination unit 41 may determine that the vehicle is in a reverse running state.

[0055] In this way, based on the analysis result by the image analysis unit 2, if the captured image satisfies the first condition that it includes a color specific to at least the rising surface 33 at at least one of the plurality of steps of the reverse running warning structure 30, the reverse running determination unit 4 determines that the vehicle is running in reverse on the road. The first condition may be that the captured image includes a specific color of a predetermined number of pixels or more.

[0056] When the specific color presence / absence determination unit 41 determines that the vehicle is in a reverse running state, it notifies the warning unit 5 that the vehicle is in a reverse running state.

[0057] FIG. 12 shows a second configuration example of the reverse running determination unit 4. The reverse running determination unit 4 includes a specific vibration presence / absence determination unit 43, a specific color pattern presence / absence determination unit 44, and a specific color pattern setting unit 45. To prevent misjudgment, the reverse running determination unit 4 may determine that the vehicle is in a reverse running state based on the pattern of the yellow color portion 33Y applied to the rising surface 33. In the specific color pattern setting unit 45, a color identification value indicating the color of the yellow color portion 33Y and the pattern of the yellow color portion 33Y are set.

[0058] In the first example shown in FIG. 7, the pattern of the yellow color - matching portion 33Y is such that a specific color exists at a predetermined interval in the horizontal direction of the frame, and the specific colors existing at the predetermined intervals are arranged vertically in the frame with different positions in the horizontal direction. In the second example shown in FIG. 8, the pattern is such that specific colors extending a predetermined length in the horizontal direction of the frame are arranged at a predetermined interval in the vertical direction of the frame. In the third example shown in FIG. 9, the pattern is such that specific colors extending in the horizontal direction of the frame exist in groups within a predetermined range in the vertical direction of the frame, and the specific colors extending in the horizontal direction become longer in order as they approach the central part from the upper and lower ends of the group.

[0059] The unique - color pattern presence / absence determination unit 44 determines that it is in a reverse - driving state if the analysis data of the frame includes color - identification values within a predetermined range of color - identification values centered on the color - identification value set in the unique - color pattern setting unit 45 and includes a pattern similar to the pattern set in the unique - color pattern setting unit 45 within a range of a predetermined error. When the unique - color pattern presence / absence determination unit 44 determines that it is in a reverse - driving state, it notifies the warning unit 5 that it is in a reverse - driving state.

[0060] In this way, based on the analysis result by the image analysis unit 2, if the reverse - driving determination unit 4 satisfies the second condition that the rising surface 33 at two or more steps includes a predetermined pattern formed by a unique color, the reverse - driving determination unit 4 may determine that the vehicle is driving in reverse on the road.

[0061] When the camera 1 photographs the reverse - driving warning structure 30, the luminance of the portion of the yellow color - matching portion 33Y in the photographed image is different from the luminance of the portion of the black color - matching portion 33B. The reverse - driving determination unit 4 may also determine whether it is in a reverse - driving state based on whether the rising surface 33 includes a unique luminance instead of a unique color. In this case, a white color - matching portion or a gray color - matching portion may be used instead of the yellow color - matching portion 33Y.

[0062] Also, in this case, the image analysis unit 2 may analyze the luminance of the captured image. The reverse running determination unit 4 may have a specific luminance presence / absence determination unit instead of the specific color presence / absence determination unit 41, and a specific luminance setting unit instead of the specific color setting unit 42. Further, it may have a specific luminance pattern presence / absence determination unit instead of the specific color pattern presence / absence determination unit 44, and a specific luminance pattern setting unit instead of the specific color pattern setting unit 45.

[0063] Furthermore, the reverse running determination unit 4 may determine whether it is in a reverse running state based on whether the rising surface 33 includes a specific color and a specific luminance. In this case, the image analysis unit 2 may analyze both the color and the luminance of the captured image.

[0064] Thus, the image analysis unit 2 may analyze at least one of the color and the luminance of the captured image. The reverse running determination unit 4 may determine whether it is in a reverse running state based on whether the captured image includes a specific color or luminance of the rising surface 33. However, it is possible to reduce misjudgments more by the reverse running determination unit 4 determining whether it is in a reverse running state based on whether the captured image includes a specific color of the rising surface 33 rather than based on whether the captured image includes a specific luminance of the rising surface 33.

[0065] FIG. 13 shows a specific configuration example of the warning unit 5. The warning unit 5 includes a warning voice selection unit 51, a warning voice storage unit 52, a D / A converter 53, a speaker 54, a warning image selection unit 55, a warning image storage unit 56, a driving unit 57, and a display unit 58. The display unit 58 is a display panel such as a liquid crystal panel.

[0066] When the reverse driving determination device 100 is built into the drive recorder, the speaker included in the drive recorder may be used as the speaker 54, and the display panel and its driving unit included in the drive recorder may be used as the display unit 58 and the driving unit 57. When the reverse driving determination device 100 is built into the car navigation device, the speaker provided in the vehicle for outputting the voice generated by the car navigation device may be used as the speaker 54, and the display panel and its driving unit included in the car navigation device may be used as the display unit 58 and the driving unit 57. That is, the speaker 54, the driving unit 57, and the display unit 58 may be configured as components external to the reverse driving determination device 100.

[0067] When the warning voice selection unit 51 is notified by the specific color presence / absence determination unit 41 or the specific color pattern presence / absence determination unit 44 that the vehicle is in a reverse driving state, the warning voice selection unit 51 reads out, for example, warning voice data such as "You are driving in reverse. Please stop." from the warning voice storage unit 52 and supplies it to the D / A converter 53. The D / A converter 53 converts the input warning voice data into an analog signal and supplies it to the speaker 54. Thereby, a warning voice such as "You are driving in reverse. Please stop." is output from the speaker 54.

[0068] When the warning image selection unit 55 is notified by the specific color presence / absence determination unit 41 or the specific color pattern presence / absence determination unit 44 that the vehicle is in a reverse driving state, the warning image selection unit 55 reads out warning image data including, for example, a sentence "You are driving in reverse. Please stop." from the warning image storage unit 56 and supplies it to the driving unit 57. The driving unit 57 drives the display unit 58 to display a warning image based on the input warning image data on the display unit 58. Thereby, as shown in FIG. 14, a warning image including a sentence "You are driving in reverse. Please stop." is displayed on the display unit 58.

[0069] The warning unit 5 may warn the driver of the reverse vehicle 40 by voice or image. However, the warning unit 5 is preferably configured to warn the driver of the reverse vehicle 40 by at least voice rather than by image only.

[0070] If the driver of the reverse-running vehicle 40 does not notice the warning voice emitted from the speaker 54 and the warning image displayed on the display unit 58, or even if the driver notices but continues to reverse in the deceleration lane 23, the reverse-running vehicle 40 reaches the reverse-warning structure 30 and travels on the reverse-warning structure 30. The presence / absence determination unit 43 for specific vibration shown in FIG. 11 or FIG. 12 determines the presence or absence of specific vibration applied to the reverse-running vehicle 40 when the reverse-running vehicle 40 travels on the reverse-warning structure 30 based on the vibration applied to the reverse-running vehicle 40 detected by the acceleration sensor 3.

[0071] Since the reverse-warning structure 30 is formed with rising surfaces 33 every 500 mm, vibration is applied to the reverse-running vehicle 40 at substantially regular intervals. The range from the minimum speed to the maximum speed can be assumed to a certain extent when the reverse-running vehicle 40 reverses in the deceleration lane 23. The presence / absence determination unit 43 for specific vibration determines that the reverse-running vehicle 40 is traveling on the reverse-warning structure 30 if the vibration applied to the reverse-running vehicle 40 is at substantially regular intervals and the vibration is within a predetermined frequency range.

[0072] When the presence / absence determination unit 43 for specific vibration determines that the reverse-running vehicle 40 is traveling on the reverse-warning structure 30, it notifies the warning unit 5 and the instruction unit 6 that the reverse state continues.

[0073] When the warning voice selection unit 51 is notified by the presence / absence determination unit 43 for specific vibration that the reverse state continues, it reads out warning voice data such as "Forced stop" from the warning voice storage unit 52 and supplies it to the D / A converter 53. The D / A converter 53 converts the input warning voice data into an analog signal and supplies it to the speaker 54. Thereby, a warning voice of "Forced stop" is output from the speaker 54.

[0074] When the warning image selection unit 55 is notified by the forward and reverse running state determination unit 43 that the reverse running state continues, the warning image selection unit 55 reads warning image data including a sentence such as "Forced stop will be performed" from the warning image storage unit 56 and supplies the data to the drive unit 57. The drive unit 57 drives the display unit 58 to display a warning image based on the input warning image data on the display unit 58. As a result, as shown in FIG. 15, a warning image including a sentence "Forced stop will be performed" is displayed on the display unit 58.

[0075] In FIG. 1, when the instruction unit 6 is notified by the forward and reverse running state determination unit 43 that the reverse running state continues, the instruction unit 6 instructs the running control unit 11 to stop the vehicle. When the running control unit 11 is instructed by the instruction unit 6 to stop the vehicle, the running control unit 11 controls the brake 13 to gradually decelerate the reverse vehicle 40 and forcibly stop it.

[0076] Using the flowchart shown in FIG. 16, the reverse running determination method (or reverse running prevention method) executed by the reverse running determination device 100 will be further described. When the operation of the reverse running determination device 100 is started, the camera 1 captures an image of the road surface in front of the vehicle in step S1. The image analysis unit 2 analyzes the color of the captured image in step S2. The image analysis unit 2 may analyze the luminance instead of the color. The reverse running determination unit 4 determines in step S3 whether the captured image includes a color specific to the rising surface 33 of the reverse running warning structure 30.

[0077] If the captured image does not include a color specific to the rising surface 33 in step S3 (NO), the processes in steps S1 to S3 are repeated. When the vehicle is traveling on a road where the reverse running warning structure 30 is not provided or when the vehicle is traveling forward without running in reverse on a road where the reverse running warning structure 30 is provided, the reverse running determination device 100 repeats the processes in steps S1 to S3.

[0078] If the captured image includes a color specific to the rising surface 33 in step S3 (YES), the warning unit 5 warns the driver in step S4 that the vehicle is running in reverse by voice or image. Subsequently, the reverse running determination unit 4 determines in step S5 whether a vibration specific to when the vehicle runs on the reverse running warning structure 30 is applied. If no vibration specific to when the vehicle runs on the reverse running warning structure 30 is applied (NO), since it means that the driver has stopped the vehicle, the process is terminated.

[0079] If a vibration specific to when the vehicle runs on the reverse running warning structure 30 is applied in step S5 (YES), the warning unit 5 warns the driver in step S6 to forcibly stop the vehicle by voice or image. Subsequently, the instruction unit 6 instructs the running control unit 11 to forcibly stop the vehicle in step S7 and terminates the process.

[0080] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0081] 1 Camera 2 Image Analysis Unit 3 Acceleration Sensor 4 Reverse Running Determination Unit 5 Warning Unit 6 Instruction Unit 11 Running Control Unit 12 Drive Source 13 Brake 30 Reverse Running Warning Structure 31 Flat Surface 32, 35 Inclined Surfaces 33, 33a to 33k, 34 Rising Surfaces 33B Black Color-Matching Part 33Y Yellow Color-Matching Part 41 Specific Color Presence / Absence Determination Unit 42 Specific Color Setting Unit 43 Specific Vibration Presence / Absence Determination Unit 44 Specific Color Pattern Presence / Absence Determination Unit 45 Specific Color Pattern Setting Unit 51 Warning Sound Selection Unit 52 Warning Sound Memory Unit 53 D / A Converter 54 Speaker 55 Warning Image Selection Unit 56 Warning Image Memory Unit 57 Driving Unit 58 Display Unit 100 Reverse Running Judgment Device

Claims

1. An image analysis unit that acquires a captured image of the road surface of the road on which the vehicle travels, captured by a camera that captures the front of the vehicle, and analyzes at least one of the color and brightness of the captured image; When the vehicle is traveling on a road provided with a reverse travel warning structure on the road surface, based on the analysis result by the image analysis unit, the captured image is at least the reverse travel warning structure has a plurality of steps formed at a predetermined interval in the direction in which the vehicle travels on the road. When the first condition that it includes a color or brightness peculiar to the surface that is captured only when the vehicle is traveling in reverse on the road is satisfied, a reverse travel determination unit that determines that the vehicle is traveling in reverse on the road; A reverse travel determination device comprising:

2. The reverse travel determination unit, based on the analysis result by the image analysis unit, when the captured image satisfies a second condition that it includes a predetermined pattern formed by a color or brightness peculiar to the surface that is captured only when the vehicle is traveling in reverse on two or more of the plurality of steps, The reverse travel determination device according to claim 1, wherein it is determined that the vehicle is traveling in reverse on the road.

3. The reverse travel determination device according to claim 1 or 2, further comprising a warning unit that warns the driver of the vehicle by voice or image when the reverse travel determination unit determines that the vehicle is traveling in reverse on the road.

4. The reverse travel determination unit determines, based on the vibration applied to the vehicle detected by an acceleration sensor, whether a vibration peculiar to when the vehicle travels on the reverse travel warning structure is applied to the vehicle. When the reverse travel determination unit determines that a vibration peculiar to when the vehicle travels on the reverse travel warning structure is applied to the vehicle, an instruction unit that instructs the running control unit that controls the running of the vehicle to forcibly stop the vehicle is further provided. The reverse travel determination device according to claim 1 or 2.

5. A camera that captures the front of the vehicle captures the road surface on which the vehicle travels, An image analysis unit analyzes at least one of the color and brightness of the captured image by the camera. When the vehicle is traveling on a road provided with a reverse running warning structure on the road surface, based on the analysis result by the image analysis unit, the reverse running determination unit determines whether the captured image includes at least a color or luminance specific to a surface that is captured only when the vehicle is running in reverse on the road, at least at one of a plurality of steps formed at a predetermined interval in the direction in which the vehicle travels on the road, which the reverse running warning structure has. If the condition is satisfied, it is determined that the vehicle is running in reverse on the road. Reverse running determination method.

Images