DRIVING ASSISTANCE DEVICE

Abstract

A driver assistance device (1) for assistance in driving a vehicle (65), comprising: an object recognition unit (31) designed to detect objects in front of the vehicle (65), a vehicle speed detection unit (32) designed to detect the speed of the vehicle (65), and a driver assistance unit (34) designed to issue a warning to a driver of the vehicle (65) when the object detection unit (31) detects that there are two or more traffic light signs (61, 62) in front of the vehicle (65), characterized by the fact that the driver assistance unit (34) is designed to issue a warning to the driver of the vehicle (65) when the object detection unit (31) detects that a sign indicating a prohibition on proceeding straight ahead is detected by one of the two or more traffic light signs (61, 62) closest to the vehicle (65), and a sign indicating permission to proceed or permission to proceed in a limited direction is detected by at least one more distant traffic light sign (62) that is farther away from the vehicle (65) than the nearest traffic light sign (61), and the speed of the vehicle (65) detected by the vehicle speed detection unit (32) exceeds an upper limit for such a speed at which the vehicle (65) can be stopped at a position where the vehicle (65) can be stopped in accordance with the sign indicated by the nearest traffic light sign (61). wherein the upper limit for the speed is calculated by adding an increase in a vehicle movement distance attributable to a false character recognition to a distance between the vehicle (65) and a position at which the vehicle is to stop.

Description

[0001] The present invention relates to a driver assistance device for providing support when driving a vehicle.

[0002] JP 2016-045 681 A discloses a safety driving assistance system for alerting a driver who is driving a vehicle carelessly, thereby preventing the vehicle from entering an intersection contrary to a sign or signal. More precisely, in a case where the vehicle must stop at a red light before an intersection, the safety driving assistance system adds a free-driving distance from the point when the driver recognizes this situation to the point when the driver begins to decelerate the vehicle, and a braking distance required to stop the vehicle's deceleration, and specifies a position within the total distance of the free-driving distance and the braking distance before the intersection position as a detection limit position.In a case where the driver is driving the vehicle carelessly at the moment the vehicle reaches the detection limit position, the safety driving assistance system alerts the driver by a sound or a light.

[0003] However, every country has roads or carriageways that run straight and where there are two or more intersections, pedestrian crossings, or similar features in the direction of travel, and where traffic lights are installed at each intersection, pedestrian crossing, or similar location. When a vehicle is traveling on such a road, the signals or signs displayed by two or more traffic lights installed in a line in the direction of travel will simultaneously enter the driver's field of vision.

[0004] In this case, the driver may fail to distinguish between the signal displayed by the nearest traffic light and the signal displayed by the traffic light farther away from the vehicle. For example, if the signal displayed by the nearest traffic light is red and the signal displayed by the farther away traffic light is blue, the driver may confuse the signal displayed by the farther away traffic light with the signal displayed by the nearest traffic light and drive the vehicle against or in contradiction to the signal displayed by the nearest traffic light into an intersection, pedestrian crossing, or similar location where the nearest traffic light is located.

[0005] In the event that two or more traffic signals as described above simultaneously enter the driver's front field of vision and the driver therefore misinterprets the signals, even when using the safety driver assistance system disclosed in JP 2016-045 681 A, it is difficult to prevent the driver from driving the vehicle into the intersection, pedestrian crossing, or the like where the next traffic signal is located, contrary to the signal indicated by the next traffic signal.

[0006] In other words, the safety driving assistance system disclosed in JP 2016-045 681 A alerts a driver who is driving carelessly the moment the vehicle reaches a limit detection position. The limit detection position is the position of the combined distance of a free-driving distance and a braking distance before an intersection where the vehicle is supposed to stop. Here, the combined distance of a free-driving distance and a braking distance is generally referred to as a stopping distance. Therefore, the combined distance of a free-driving distance and a braking distance will subsequently be referred to as a stopping distance. It is assumed that when a driver is currently driving a vehicle carelessly, the vehicle is essentially maintaining a constant speed.If a stopping distance is calculated based on the vehicle's speed at that time, and a stopping distance position is specified before an intersection where the vehicle is to stop, and the driver is alerted at the specified position, it may therefore be possible to prevent the vehicle from entering the intersection.

[0007] However, in the case where, as described above, two or more traffic signals simultaneously enter the driver's field of vision and the driver therefore misinterprets the signals, there is a risk that the driver will accelerate the vehicle at a position near the intersection, pedestrian crossing, or similar location where the next traffic signal is located, as described below. Even if the signal displayed by the nearest traffic signal is red because the signal displayed by the more distant traffic signal is blue, if the driver misinterprets the signal displayed by the nearest traffic signal as blue, the driver might, for example, consider crossing the intersection, pedestrian crossing, or similar location where the next traffic signal is located before the signal changes to yellow and the vehicle accelerates.Accelerating towards the intersection, pedestrian crossing, or similar location. Even if a stopping distance is calculated based on the vehicle's speed after acceleration, and a stopping distance position before the intersection where the vehicle is supposed to stop is specified as an alert position, the vehicle may have already passed this position. In this case, it is difficult to prevent the vehicle from entering the intersection.

[0008] From JP 2007 - 26 299 A a driver assistance device is known on which the preamble of claim 1 is based.

[0009] From JP 2009 - 143 308 A, an electric vehicle braking device is known which is able to increase the safety of a vehicle by appropriately generating braking force in an electric brake actuated by a motor, depending on a stopping position and a speed of the vehicle.

[0010] It is therefore an object of at least one aspect of the present invention to provide a driver assistance device that can prevent a driver from driving a vehicle into an intersection, pedestrian crossing or the like, where a traffic light signal closest to the vehicle is located, against or in contradiction to a signal indicated by the nearest traffic light signal, since the driver of the vehicle confuses a signal indicated by a more distant traffic light signal with the signal indicated by the nearest traffic light signal.

[0011] According to the present invention, a driver assistance device with the features of claim 1 is provided for assisting the driver of a vehicle, comprising: an object detection unit configured to detect objects in front of the vehicle, a vehicle speed detection unit configured to detect the speed of the vehicle, a driver assistance unit configured to issue a warning to the driver of the vehicle when the object detection unit detects that there are two or more traffic lights in front of the vehicle, and a sign indicating a prohibition on driving straight ahead from one of the two or more traffic lights closest to the vehicle, and a sign indicating a prohibition on driving straight ahead from at least one more distant traffic light that is farther away from the vehicle than the nearest traffic light.indicates permission to proceed or permission to proceed in a limited direction, and the speed of the vehicle, as detected by the vehicle speed detection unit, exceeds an upper limit for such speed at which the vehicle can be safely stopped at a position where the vehicle can be stopped in accordance with the signal indicated by the next traffic light signal.

[0012] According to the above aspect, it can be prevented that a driver enters an intersection, pedestrian crossing, or the like where there is a traffic light sign closest to the vehicle, against or in contradiction to a sign indicated by the nearest traffic light sign, since the driver of the vehicle confuses a sign indicated by a more distant traffic light sign with the sign indicated by the nearest traffic light sign.

[0013] The enclosed drawings show: Fig. 1. An explanatory or illustrative view showing a road where there are two traffic lights and vehicles driving on the road. Fig. 2 An explanatory view illustrating two traffic light signals that are in the front field of vision of a driver of a vehicle of Fig. 1 come, Fig. 3 a block diagram illustrating the configuration of a driver assistance device according to an embodiment of the present invention, Fig. 4 an explanatory view illustrating images acquired by depicting two or more traffic light signals located in front of the vehicle, Fig. 5 a flowchart illustrating a method which the driver assistance device according to the embodiment of the present invention performs when the vehicle is in motion, and Fig. 6 a flowchart illustrating a method which the driver assistance device according to the embodiment of the present invention performs when the vehicle is stationary at a position where the vehicle is to stop.

[0014] A driver assistance device of an embodiment according to the present invention is a driver assistance device for supporting the driving of a vehicle and comprises an object recognition unit, a vehicle speed detection unit and a driver assistance unit.

[0015] The object detection unit recognizes objects located in front of the vehicle. It can detect that there are two or more traffic lights in front of the vehicle. Furthermore, the object detection unit can identify the closest traffic light to the vehicle and the traffic light that is farther away from the vehicle than the nearest traffic light, among any two or more traffic lights in front of the vehicle. Additionally, the object detection unit can identify signals displayed by individual traffic lights.

[0016] Traffic signals come in two types: standard traffic signals and arrow-type traffic signals. Standard traffic signals indicate permission to proceed, stop, prohibition, and so on. For example, in Japan, permission to proceed is indicated by a blue (or green) light, stopping is indicated by a yellow light, and prohibition is indicated by a red light. Arrow-type traffic signals indicate permission to proceed straight ahead, permission to turn left, permission to turn right, stop, prohibition, and so forth.For example, in Japan, permission to go straight, permission to turn left, and permission to turn right are signaled by combining the activation of a red light with the activation of blue (green) arrow lights indicating the permitted directions of travel. The object recognition unit can recognize the colors, shapes, etc., of individual traffic light signals, thereby identifying the signals displayed by those signals.

[0017] The vehicle speed detection unit detects the speed of the vehicle.

[0018] In a case where there are two or more traffic light signals ahead of the vehicle, and a signal indicated by the nearest of the two or more traffic light signals prohibits driving straight ahead, and a signal indicated by at least one of the more distant traffic light signals indicates permission to proceed or permission to proceed in a limited direction, and the vehicle's speed, as detected by the speed detection unit, exceeds an upper limit for such speed as is possible to bring the vehicle to a safe stop at a position where the vehicle is intended to stop, the driver assistance device issues a warning to the vehicle's driver.

[0019] A prohibition on driving straight ahead is a prohibition on continuing, a permission to turn left, or a permission to turn right. Furthermore, a permission to continue in a restricted direction is a permission to drive straight ahead, a permission to turn left, or a permission to turn right.

[0020] Furthermore, the position where the vehicle is to stop is a position where the vehicle is to stop according to the signal indicated by the nearest traffic signal. For example, in a case where there is no other vehicle between the vehicle and the intersection, pedestrian crossing, or the like where the nearest traffic signal is located, the position where the vehicle is to stop is exactly before a stop line of the intersection, pedestrian crossing, or the like where the nearest traffic signal is located (in a case where there is no stop line, exactly before the intersection, pedestrian crossing, or the like). Furthermore, in a case where there is a stationary oranother vehicle stopped in front of the stop line of the intersection, pedestrian crossing or the like, where the next traffic light is located, the position where the vehicle should stop, a position which is behind the other vehicle and at a suitable distance from the other vehicle.

[0021] If such a speed at which it is possible to safely stop the vehicle at a position where the vehicle is to stop is referred to as the speed at which safe stopping is possible, then an upper limit for such a speed at which safe stopping is possible is determined on the basis of the distance between the vehicle and the position where the vehicle is to stop, and the like.

[0022] In a situation where two or more traffic signals appear simultaneously in the driver's forward field of vision, and one signal from the nearest signal indicates a prohibition against proceeding straight ahead, while the signal from the more distant signal permits proceeding or proceeding in a restricted direction, there is a possibility that, if the vehicle's speed exceeds the upper limit for safe stopping, the driver may confuse the signal from the more distant signal with the signal from the nearest one. If the driver is left misinterpreting the signals, there is a risk that the vehicle will collide with or be struck by the traffic signal.The vehicle enters the intersection, pedestrian crossing, or similar area where the next traffic light is located, contrary to the signal indicated by the next traffic light. According to the driver assistance device of the embodiment, a warning can be issued to the driver in this case. This can prompt the driver to realize the misinterpretation and brake the vehicle. Therefore, it can prevent the vehicle from entering the intersection, pedestrian crossing, or similar area where the next traffic light is located, contrary to the signal indicated by the next traffic light, and the vehicle's preventive safety capability is improved.

[0023] In the event that two or more traffic signals simultaneously enter the driver's field of vision, and the driver consequently misinterprets the signals as described above, there is also a risk that the driver will accelerate the vehicle at a position near the intersection, pedestrian crossing, or similar location where the next traffic signal is located. Even in this case, if the vehicle accelerates beyond the upper limit for safe stopping, the driver assistance device of the embodiment according to the present invention issues a warning so that the driver can stop accelerating. Therefore, it can be prevented that the vehicle enters the intersection, pedestrian crossing, or similar location where the next traffic signal is located, contrary to the signal indicated by that next traffic signal.

[0024] Fig. Figure 1 shows a road or road 51 where there are two traffic light signs 61 and 62 and vehicles such as vehicle 65 are driving on the road. Fig. Figure 2 shows the two traffic light signs 61 and 62, etc., which are in the front field of vision of a driver of vehicle 65. Fig. 1 come. In Fig. 1. Road 51 extends straight along its length, and there are, for example, two intersections, 52 and 53, along its length. There is also a pedestrian crossing, 54, at intersection 52. Furthermore, traffic lights 61 and 62 are located at intersections 52 and 53, respectively. Vehicle 65 is traveling on Road 51 from a position away from intersections 52 and 53, heading towards them. At this time, the two traffic lights, 61 and 62, located at intersections 52 and 53, simultaneously enter the driver's field of vision, as shown in Figure 1. Fig. 2 shown. Fig. 2. Traffic sign 61 is the traffic sign closest to vehicle 65, and traffic sign 62 is the traffic sign farther away from vehicle 65 than the nearest traffic sign.

[0025] Fig. Figure 3 shows the configuration of a driver assistance device 1 of the embodiment according to the present invention. The driver assistance device 1 of the embodiment according to the present invention is a device for providing support when driving the vehicle 65 and is installed on the vehicle 65. As shown in Fig. Figure 3 shows that the driver assistance device 1 comprises an imaging device 11, an ultrasonic sensor 12, a laser radar 13, and a millimeter-wave radar 14 as devices for detecting objects located in front of the vehicle 65. The imaging device 11 is a device for imaging an area in front of the vehicle 65, thereby generating images, and is, for example, a digital camera. Based on the images generated by the imaging device 11, the positions, shapes, colors, etc., of objects located in front of the vehicle 65 can be detected. Meanwhile, the ultrasonic sensor 12, the laser radar 13, and the millimeter-wave radar 14 are devices for detecting objects located approximately at short distance, medium distance, and long distance, respectively.The ultrasonic sensor 12, the laser radar 13 and the millimeter wave radar 14 can be used to measure the distances between the vehicle and objects located in front of the vehicle 65.

[0026] Furthermore, the driving assistance device 1 includes a vehicle speed sensor 15, an acceleration sensor 16 and an angular velocity sensor 17 as devices for detecting the driving state of the vehicle 65. The vehicle speed sensor 15, the acceleration sensor 16 and the angular velocity sensor 17 each detect the speed, the acceleration and the angular velocity of the vehicle 65.

[0027] Furthermore, the driver assistance device 1 includes a GPS receiver (Global Positioning System) 18 as a device for determining the position of the vehicle 65. The vehicle speed sensor 15, the acceleration sensor 16, and the angular velocity sensor 17 can also be used to determine the position of the vehicle 65. In addition, the driver assistance device 1 has an external storage device 21, and the external storage device 21 contains map data. The map data can be used to determine the position of the vehicle 65, the positions of the road 51, the intersections 52 and 53, the pedestrian crossing 54, and the traffic lights 61 and 62, etc.

[0028] Furthermore, the driver assistance device 1 includes a weather detection unit 19 for detecting weather conditions. The weather detection unit 19 includes, for example, a device for detecting raindrops.

[0029] Furthermore, the driver assistance device 1 comprises a vibrator 22, a loudspeaker 23, and a display or indicator device 24 as a device for warning the driver. The vibrator 22 is a device for generating vibrations (a vibration generating device) and is installed, for example, on the handle or adjustment lever of the vehicle 65, the driver's seat, or the like. The vibrator 22 warns the driver by means of vibrations. Meanwhile, the loudspeaker 23 warns the driver by generating a warning sound. The display 24 warns the driver by displaying a warning message. The driver assistance device may also include a warning lamp to warn the driver by means of a warning light. The driver assistance device 1 also comprises a braking device 25 for braking the vehicle 65. The braking device 25 is a device for automatic or automated braking of the vehicle 65 in accordance with an instruction from a control unit 26.

[0030] Furthermore, the driver assistance device 1 includes the control unit 26. The control unit 26 comprises a CPU (a central processing unit) and an internal storage device. The control unit 26 can be implemented by adding a dedicated control unit for a driver assistance procedure to the vehicle 65 or by using an existing drive motor control unit to control the driving of the vehicle 65, etc. The control unit 26 functions as an object detection unit 31, a driving condition detection unit 32, a distance detection unit 33, a driver assistance unit 34, a road surface condition detection unit 35, and a weather detection unit 36, for example, by reading (or retrieving) programs stored in the internal storage device and executing the programs.

[0031] The object detection unit 31 detects objects located in front of the vehicle 65 based on images generated by the imaging device 11 and a detection signal output from the ultrasonic sensor 12, the laser radar 13, or the millimeter-wave radar 14. More precisely, the object detection unit 31 detects whether there are any traffic lights in front of the vehicle 65, or the number of traffic lights in front of the vehicle. In the case of two or more traffic lights in front of the vehicle 65, the object detection unit 31 also identifies the nearest traffic light and the more distant traffic light. Furthermore, the object detection unit 31 detects signs displayed by individual traffic lights located in front of the vehicle 65.

[0032] Fig. Figure 4 shows images acquired by imaging areas in front of the vehicle 65 using the imaging device 11 while the vehicle 65 was driving on roads that exist at various locations. In each of the images (1), (2) and (3) of Fig. In image 4, there are two traffic light signs, 61 and 62. In image (1), the nearest traffic light sign 61 is larger than a more distant traffic light sign 62, and the nearest traffic light sign 61 is higher than the more distant traffic light sign 62. In image (2), the nearest traffic light sign 61 and the more distant traffic light sign 62 partially overlap, but, similar to image (1), the nearest traffic light sign 61 is larger than the more distant traffic light sign 62, and the nearest traffic light sign 61 is higher than the more distant traffic light sign 62. Thus, the images differ in the sizes and positions of the nearest traffic light sign 61 and the more distant traffic light sign 62 that they encompass.The object recognition unit 31 can detect the nearest traffic light 61 and the more distant traffic light 62 based on the size relationship between the individual traffic light signs 61 and 62 depicted in the images and their positional relationship. However, in a case where the road is on a slope and the nearer side is lower and the farther side is higher, as in image (3), the nearest traffic light 61 may be lower than the more distant traffic light 62. Even in this case, the object recognition unit 31 can detect the nearest traffic light 61 and the more distant traffic light 62 not only because the road is on a slope, but also because of the size relationship between the individual traffic light signs and their positional relationship.Furthermore, an image (4) includes three traffic light signs, and even in this case, the object recognition unit 31 can recognize the individual traffic light signs by recognizing the size relationship of the individual traffic light signs and the positional relationship between them. To recognize the positional relationship of individual traffic light signs, information that is recoded or contained in the map data can also be used.

[0033] In addition, one image (5) includes Fig. 4. A traffic light sign 61, which is closest to the vehicle and is a standard traffic light sign, and a more distant traffic light sign 62, which is an arrow-type traffic light sign. Generally, the signals of a standard traffic light sign are indicated by lights that have different on / off states (a steady state, a steady state, or a flashing state) and different colors (red, yellow, or blue (green)). Furthermore, the signals of an arrow-type traffic light sign are indicated by lights that have different on / off states and different shapes (arrow directions indicated by the lights). Based on the on / off states, colors, and shapes of the individual traffic light signs 61 and 62 included in each image, the object recognition unit 31 can identify the signals indicated by the individual traffic light signs 61 and 62.

[0034] Meanwhile, the driving condition detection unit 32 detects the driving condition of the vehicle 65. More precisely, the driving condition detection unit 32 detects the speed of the vehicle 65, whether the vehicle is stationary or not, and the like, based on a detection signal output from the vehicle speed sensor 15.

[0035] The distance detection unit 33 detects the distance between vehicle 65 and a position where the vehicle is to stop. The position where the vehicle is to stop is a position where the vehicle is to stop according to a signal displayed by the next traffic light signal. For example, in a case where vehicle 65 is on road 51, which is in Fig. As shown in Figure 1, if vehicle 65 is moving and there is no other vehicle 66 between vehicle 65 and intersection 52, where the next traffic light 61 is located, the position where vehicle 65 should stop is exactly before a stop line 55 of intersection 52, where the next traffic light 61 is located. Furthermore, if another vehicle 66 is in front of the stop line 55, the position where vehicle 65 should stop is a position that is behind the other vehicle 66 and at a suitable distance from it.Because the distance between the vehicle 65 and the position where the vehicle is to stop is detected, the position of the vehicle 65 can be determined, for example, by using information about the position of the vehicle 65 received by the GPS receiver 18, information about the position of the vehicle 65 calculated based on a detection signal from the vehicle speed sensor 18, the accelerometer 16 and the angular velocity sensor 17, and the map data stored in the external storage device 21. Furthermore, the position of the stop line 55 can be determined by using the position of the vehicle 65, which was determined in the manner described above, whereby the direction of travel of the vehicle 65 is determined based on a detection signal from the accelerometer 16 or the angular velocity sensor 17 and the map data.Furthermore, the position of the other vehicle 66, which is in front of the stop line 55, can be detected by using the imaging device 11, the laser radar 13 and the like.

[0036] The road surface condition detection unit 35 detects the condition of the road surface where the vehicle is driving. More precisely, based on images generated by the imaging device 11, etc., the road surface condition detection unit 35 detects whether the road surface is wet from rain, whether the road surface is frozen, and so on.

[0037] The weather detection unit 36 ​​detects the weather at the location of the vehicle 65 based on a detection signal output by the weather detection unit 19 and the images generated by the imaging device 11. More precisely, the weather detection unit 36 ​​detects whether it is raining, snowing, and the like at the location of the vehicle 65.

[0038] The driver assistance unit 34 performs a driver assistance procedure of issuing a warning to the driver of vehicle 65 at the appropriate time to assist the driver in driving vehicle 65.In the driver assistance procedure, the driver assistance unit 34 determines whether a warning is issued based on whether there is a traffic light sign in front of the vehicle 65 and the positions of traffic light signs in front of the vehicle, which are detected by the object recognition unit 31; signs displayed by the individual traffic light signs, which are detected by the object recognition unit 31; the speed of the vehicle 65, which is detected by the vehicle condition detection unit 32 (including detection of whether the vehicle is stationary); the distance between the vehicle 65 and the position where the vehicle is to stop, which is detected by the distance detection unit 33; the road surface condition, which is detected by the road surface condition detection unit 35; and the weather, which is detected by the weather detection unit 36.In a case where a warning needs to be issued, the driver assistance unit 34 also generates a warning sound from the speaker 23 or displays a warning message on the display 24. Furthermore, according to the driver assistance device 1 of the present embodiment, the driver can be warned by a number of methods, such as emitting a warning sound and displaying an alarm message. The driver can, for example, select which of these methods is used to issue a warning.

[0039] Fig. 5 and Fig. Figure 6 shows two driver assistance procedures that are carried out by the driver assistance unit 34. Based on a detection signal output by the vehicle speed sensor 15, the driver assistance unit 34 determines whether the vehicle is traveling at 65 km / h or not. If the vehicle is traveling at 65 km / h, the driver assistance unit 34 then executes the driver assistance procedure described in Fig. 5 is shown, while the driver assistance unit, in a case where the vehicle is stationary at 65, uses the driver assistance procedure that is in Fig. 6 is shown, executes.

[0040] First, the driver assistance system is activated by Fig. 5, which is executed when the vehicle is traveling at 65, will be described. Fig. 5 first determines whether the object recognition unit 31 has detected that there are two or more traffic light signs in front of the vehicle 65 (step S1).

[0041] In a case where the object recognition unit 31 has detected that there are two or more traffic light signs in front of the vehicle 65 (“YES” in step S1), the driver assistance unit 34 subsequently determines whether the object recognition unit 31 has detected that a sign displayed by a nearest traffic light sign 61 indicates a prohibition against driving straight ahead, and a sign displayed by a more distant traffic light sign 62 indicates permission to proceed or permission to proceed in a limited direction (step S2).

[0042] Here is a sign indicating a prohibition against proceeding straight ahead, a sign of a normal traffic light or an arrow-type traffic light indicating a prohibition against proceeding (a state where a red light is illuminated), a sign of an arrow-type traffic light indicating permission to turn left (a state where a blue (green) light indicating left is illuminated), or a sign of an arrow-type traffic light indicating permission to turn right (a state where a blue (green) light indicating right is illuminated). Additionally, a sign indicating permission to proceed is a sign of a normal traffic light indicating permission to proceed (a state where a blue (green) light is illuminated).Furthermore, a sign indicating permission to proceed in a limited direction, an arrow-type traffic signal indicating permission to proceed straight ahead (a state in which a blue (green) light indicating the forward direction is illuminated), an arrow-type traffic signal indicating permission to turn left, or an arrow-type traffic signal indicating permission to turn right.

[0043] In a case where the object recognition unit 31 has recognized that the sign displayed by the nearest traffic light sign 61 indicates a prohibition against proceeding straight ahead, and the sign displayed by the more distant traffic light sign 62 indicates permission to proceed or permission to proceed in a restricted direction ("YES" in step S2), the driver assistance unit 34 subsequently determines whether the speed of the vehicle 65 exceeds the upper limit for the speed at which a safe stop is possible (step S3). The speed at which a safe stop is possible is such a speed at which it is possible to stop the vehicle safely at the position where the vehicle is intended to stop. In the present embodiment, an increase in a vehicle movement distance that is attributable to a false sign recognition isThe distance between the vehicle and the position where the vehicle is to stop is added to this distance. If the distance obtained by this addition is called the vehicle stopping distance, then the upper limit for the speed at which a safe stop is possible is the vehicle speed corresponding to the stopping distance. Furthermore, the speed at which a safe stop is possible will be described in detail below.

[0044] More precisely, in step S3, the driver assistance unit 34 detects the speed of vehicle 65 based on a detection signal output by the vehicle speed sensor 15. Additionally, the driver assistance unit 34 acquires the distance between vehicle 65 and the position where the vehicle is to stop from the distance detection unit 33 and adds an increment (or increase) of any vehicle movement distance attributable to a false signal recognition to the distance between vehicle 65 and the position where the vehicle is to stop. The distance obtained by this addition is referred to as the stopping distance of vehicle 65. The driver assistance unit 34 then calculates the speed of vehicle 65 that corresponds to the stopping distance, i.e., the speed at which a safe stop is possible.

[0045] Furthermore, the driver assistance unit 34 modifies the upper limit for the speed at which safe stopping is possible based on the road surface condition, detected by the road surface condition detection unit 35, and the weather, detected by the weather detection unit 36. More specifically, if the road surface is wet due to rain or snow, or if the road surface is frozen, the driver assistance unit reduces the upper limit for the speed at which safe stopping is possible.

[0046] The driver assistance unit 34 then compares the speed at which a safe stop is possible, calculated in the manner described above, with the current speed of the vehicle 65, which is detected on the basis of the detection signal output by the vehicle speed sensor 15, thereby determining whether the current speed of the vehicle 65 exceeds the upper limit of the speed at which a safe stop is possible.

[0047] In a case where the vehicle's speed 65 exceeds the upper limit for the speed at which a safe stop is possible ("YES" in step S3), the driver assistance unit 34 issues a warning (step S4). More precisely, as described above, the driver assistance unit 34 vibrates the vibrator 22, generates a warning sound from the speaker 23, or displays a warning message on the display 24. The driver assistance device 1 continues to issue the warning, for example, until the vehicle's speed becomes equal to or less than the speed at which a safe stop is possible, or until the signal displayed by the next traffic light 61 changes to permit either proceeding straight ahead or continuing on.The driver assistance procedure ends when the vehicle's speed becomes equal to or less than the speed at which a safe stop is possible, or when the signal displayed at the next traffic light sign 61 changes to a permission to proceed straight ahead or a permission to continue driving.

[0048] However, in a case where the object recognition unit 31 has not detected that there are two or more traffic lights ahead of the vehicle 65 (“NO” in step S1), or in a case where the object recognition unit 31 has not detected that the sign displayed at the nearest traffic light 61 indicates a prohibition against proceeding straight ahead and the sign displayed at the more distant traffic light 62 indicates permission to proceed or permission to proceed in a restricted direction (“NO” in step S2), or in a case where the speed of the vehicle 65 does not exceed the speed at which safe stopping is possible (“NO” in step S3), the driver assistance unit 34 terminates the driver assistance procedure without issuing a warning. The driver assistance procedure, which in Fig. The process shown in section 5 is executed repeatedly while the vehicle is driving.

[0049] According to the driver assistance procedure, which is in Fig. As shown in Figure 5, even in a case where two or more traffic light signs 61 and 62 simultaneously enter the driver's front field of vision of the vehicle 65 traveling on the roadway 51, as in Figure 5, the following applies: Fig. 2 is shown, where the driver misinterprets the signs, a warning is issued so that the driver can realize the misinterpretation and the vehicle 65 can stop safely at the position where it is supposed to stop. More precisely, in a case where the vehicle 65 is traveling on the straight road 51, where it is as in Fig. 1 shows two traffic light signs 61 and 62, as shown in Fig. Figure 2 shows that the nearest traffic light sign 61, displaying a sign prohibiting straight-ahead driving, and the more distant traffic light sign 62, displaying a sign prohibiting either continuing or proceeding in a restricted direction, simultaneously enter the driver's forward field of vision of the vehicle 65. In this situation, if the vehicle 65's speed exceeds the speed at which a safe stop is possible, the driver may confuse the sign displayed by the more distant traffic light sign 62 with the sign displayed by the closer traffic light sign 61 and mistakenly perceive the sign displayed by the nearest traffic light sign 61 as permitting either to proceed or to proceed in a restricted direction.As a result, the driver cannot recognize that it is necessary to stop vehicle 65 at the position where the vehicle is supposed to stop. If the driver is left in such a position that they misinterpret the signs, there is a risk that vehicle 65 will enter intersection 52 or pedestrian crossing 54 beyond the position where the vehicle is supposed to stop. According to the driver assistance procedure described in... Fig. As shown in Figure 5, if the driver is in such a situation, a warning is issued so that the driver can correct a false signal interpretation and take action to brake the vehicle. As a result, the vehicle 65 can be stopped safely at the position where it is supposed to stop, or at a position before the position where it is supposed to stop, and it can be prevented that the vehicle 65 enters the intersection 52 or the pedestrian crossing 54 against or in contradiction to the signal indicated by the next traffic light 61.

[0050] Now, the upper limit for the speed at which a safe stop is possible will be described. In a case where there is only one object in front of the vehicle, it is preferable to set the upper limit for the speed at which a safe stop is possible to a value lower than the upper limit for the speed at which it is possible to safely stop the vehicle directly in front of that object. More precisely, in a case where there is only one object in front of the vehicle, the upper limit for the speed at which it is possible to safely stop the vehicle directly in front of that object is a speed that corresponds to a stopping distance. This stopping distance describes the distance between the vehicle and the position directly in front of the object (the sum of a clearance distance and a braking distance).In contrast, in a case where an increase in a vehicle movement distance, which is attributable to a faulty character recognition, is added to the distance between the vehicle and the position where the vehicle is to stop, and where the distance obtained by the addition is designated as the stopping distance, it is preferable that the upper limit for the speed at which a safe stop is possible be set as a speed corresponding to the stopping distance.

[0051] Furthermore, it is preferable that the increase in a vehicle speed gap attributable to the incorrect character recognition is, for example, a vehicle movement gap set in consideration of a deceleration caused by braking when the driver accelerates the vehicle due to incorrect character recognition. It is preferable to store increases in a vehicle movement gap attributable to incorrect character recognition, for example, as a speed function determined in advance by experiments and the like, or in a data table representing the corresponding relationship between a plurality of speed ranges and increases in a vehicle movement gap attributable to incorrect character recognition, in the internal memory device of the control unit 26.

[0052] Increases in vehicle movement distance that are attributable to incorrect character recognition will be described in more detail.For example, in a case where the driver mistakenly believes that a signal displayed by the next traffic light indicates permission to proceed or permission to proceed in a restricted direction, because the signal displayed by the more distant traffic light indicates permission to proceed or permission to proceed in a restricted direction, even if the signal displayed by the next traffic light indicates a prohibition against proceeding, the driver may think to cross the intersection, pedestrian crossing, or the like where the next traffic light is located before the signal displayed by the next traffic light changes to stop (a state where the yellow light is illuminated) and accelerate the vehicle towards the intersection, pedestrian crossing, or the like.In the event that the vehicle accelerates, the stopping distance increases with the acceleration. However, the driver assistance system requires a short time to determine the vehicle's speed, the distance between the vehicle and the desired stopping position, and to calculate the speed at which a safe stop is possible before issuing a warning. Furthermore, it takes time for the driver to recognize the warning message and for the driver to correct the incorrect sign recognition. In particular, because the driver may misidentify the nearest and more distant traffic lights, but correctly recognizes the signs themselves (the colors and shapes), it can take time to correct the incorrect sign recognition.Therefore, at the point when the driver realizes that it is necessary to brake based on a warning, the actual distance between the vehicle and the stopping point is shorter than the distance used by the driver assistance system to calculate the speed required to stop safely. Consequently, in a case where the distance between the vehicle and the stopping point is simply referred to as the stopping distance, and the upper limit for the safe stopping speed is set to the speed corresponding to the stopping distance, the warning is issued too late.Therefore, there is a risk that even if the driver brakes the vehicle in response to the warning, the vehicle may enter the intersection, pedestrian crossing, or similar behind the position where the vehicle is supposed to stop.

[0053] In contrast, according to the driver assistance device 1 of the present embodiment, the speed function or the data table, which contains increases in a vehicle movement distance that is attributable to a false character recognition, is stored in advance in the internal memory of the control unit 26.The speed function or data table is a function or table generated by measuring the time required to detect the speed and the distance between the vehicle and the position where the vehicle is to stop, and calculates the speed at which a safe stop is possible, and issues the warning in the driver assistance procedure, whereby the time required for the driver to recognize the output warning, the time required for the time required to realize the false character recognition, and the like, are determined through experimentation and the like, and the distance of the vehicle's movement during the entire duration of the measured times, for example, with respect to each of a plurality of speed ranges determined during the start of an acceleration of the vehicle.The increase in vehicle movement distance attributable to the incorrect sign recognition is then added to the distance between the vehicle and the position where the vehicle is to stop. The resulting distance is called the stopping distance. When the driver assistance procedure is executed, a speed corresponding to the stopping distance is set as the upper limit for the speed at which a safe stop is possible.Since the upper limit for the speed at which a safe stop is possible is calculated using the procedure described above, the warning issue time can be brought forward, and if the driver brakes the vehicle in response to the warning, the vehicle 65 can be stopped at the position where the vehicle is supposed to stop, or before the position where the vehicle is supposed to stop, and it can be prevented that the vehicle 65 enters the intersection 52 or the pedestrian crossing 54.

[0054] The driver assistance system is now being developed by Fig. 6, which is carried out when the vehicle 65 is stationary or at rest, will be described. In Fig. 6 first determines whether the object recognition unit 31 has detected that there were two or more traffic light signs in front of the vehicle 65 (step S11).

[0055] In a case where the object recognition unit 31 has detected that there were two or more traffic light signs in front of the vehicle 65 (“YES” in step S11), the driver assistance unit 34 subsequently determines whether the object recognition unit 31 has detected a sign indicated by a traffic light sign 61 closest to the vehicle, which prohibits driving straight ahead, and a sign indicated by a more distant traffic light sign 62, which permits driving on or driving in a limited direction (step S12).

[0056] In a case where the object recognition unit 31 has detected that the sign displayed by the nearest traffic light sign 61 prohibits driving straight ahead, and the sign displayed by the more distant traffic light sign 62 permits driving forward or driving in a restricted direction (“YES” in step S12), the driving assistance unit 34 subsequently determines whether the vehicle 65 has started moving forward from the position where it is supposed to stop (step S13). More precisely, based on information about the position of the vehicle 65, acquired by the GPS receiver 18 and the like, the driving assistance unit 34 recognizes that the vehicle 65 is at a position where it is supposed to stop.In addition, the driver assistance unit 34 recognizes, on the basis of a detection signal issued by the vehicle speed sensor 15, that the vehicle 65 has started to move forward.

[0057] In a case where the vehicle 65 has begun to move forward from the position where it is supposed to stop (“YES” in step S13), the driver assistance unit 34 issues a warning (step S14). The driver assistance device 1 continues to issue the warning, for example, until the vehicle 65 has begun to stop moving forward or until the signal displayed by the next traffic light 61 changes to a permission to proceed straight ahead or a permission to continue. When the vehicle stops or the signal displayed by the next traffic light 61 changes to a permission to proceed straight ahead or a permission to continue, the driver assistance procedure ends.

[0058] However, in a case where the object recognition unit 31 has detected that there are two or more traffic light signs ahead of the vehicle 65 (“NO” in step S11), or in a case where the object recognition unit 31 has not detected that the sign displayed by the nearest traffic light sign 61 indicates a prohibition against proceeding straight ahead, and the sign displayed by the more distant traffic light sign 62 indicates permission to proceed or permission to proceed in a restricted direction (“NO” in step S12), or in a case where the vehicle 65 has not started to move forward from the position where the vehicle is supposed to stop (“NO” in step S13), the driver assistance unit 34 terminates the driver assistance procedure without issuing a warning. The driver assistance procedure that was initiated in Fig. As shown in Figure 6, this process is repeated while the vehicle is in a stationary state with the drive motor running.

[0059] According to the driver assistance procedure, which is in Fig. As shown in Figure 6, if vehicle 65 is stationary at the position where it is supposed to stop, and the nearest traffic light sign 61 and the more distant traffic light sign 62 simultaneously enter the driver's forward field of vision, and the driver misinterprets the signs, a warning is issued so that the driver can realize the misinterpretation. Therefore, it can be prevented that vehicle 65 moves forward from the position where it is supposed to stop and enters the intersection 52 or the pedestrian crossing 54.More precisely, when the vehicle is stationary at the position where it is to stop, the nearest traffic light sign 61, displaying the sign prohibiting straight-ahead travel, and the more distant traffic light sign 62, displaying the sign prohibiting either continuing or proceeding in a restricted direction, simultaneously enter the driver's forward field of vision. In this situation, if the vehicle begins to move forward, the driver may confuse the sign displayed by traffic light sign 62 with the sign displayed by the nearest traffic light sign 61 and mistakenly perceive the sign displayed by the nearest traffic light sign 61 as permitting either to proceed or to proceed in a restricted direction.As a result, the driver cannot recognize that vehicle 65 must stop at the position where it is supposed to stop. If the driver is left in such a position to misinterpret the signs, there is therefore a risk that vehicle 65 will enter intersection 52 or pedestrian crossing 54. According to the driver assistance procedure described in... Fig. As shown in Figure 6, if the driver is in such a situation, a warning is issued so that the driver can recognize the incorrect sign interpretation and stop the vehicle 65 immediately after it starts moving forward. Therefore, it can be prevented that the vehicle 65 enters the intersection 52 or the pedestrian crossing 54 contrary to the sign indicated by the next traffic light.

[0060] As described above, according to the driver assistance device 1 of the present embodiment, it can be prevented that the driver of the vehicle 65 drives the vehicle 65 into the intersection 52 or into the pedestrian crossing 54, where the next traffic light 61 is installed, contrary to the sign shown by the next traffic light 61, since the driver considers the sign shown by the more distant traffic light 62 to be the sign shown by the next traffic light 61.

[0061] Furthermore, the driver assistance device 1 of the present embodiment modifies the upper limit for the speed at which safe stopping is possible based on the road surface condition detected by the road surface condition detection unit 35. In this way, in a case where the braking distance of the vehicle 65 is expected to be longer, for example, in a case where the road surface is wet from rain or frozen, the upper limit for the speed at which safe stopping is possible can be reduced. Therefore, if the driver continues driving the vehicle 65 due to the false sign recognition described above, a warning can be issued to the driver at an earlier time than would be the case in dry or cloudy weather.Even in a case where the road surface is wet from rain or frozen, it can therefore be prevented that the vehicle enters the intersection, pedestrian crossing or the like in contradiction to the signal indicated by the nearest traffic light.

[0062] Furthermore, according to the driver assistance device 1 of the present embodiment, the upper limit for the speed at which safe stopping is possible is changed based on the weather detected by the weather detection unit 36. In this way, if the vehicle's braking distance is expected to be longer due to rain or snow, the upper limit for the speed at which safe stopping is possible can be reduced. Therefore, if the driver continues driving the vehicle 65 due to the false sign recognition described above, a warning can be issued to the driver at an earlier time than if it were not raining or snowing.Therefore, even in a case where it is raining or snowing, it can be prevented that the vehicle enters the intersection, pedestrian crossing or the like in contradiction to a signal indicated by the nearest traffic light signal.

[0063] Furthermore, the driver assistance device 1 of the present embodiment has a configuration in which the vibrator 22 vibrates to warn the driver. Therefore, even in cases where it is difficult for the driver to see the display 24 because the driver is driving the vehicle 65, or where it is difficult for the driver to hear a warning sound from the speaker 23 due to ambient noise, the driver can still be reliably warned. This configuration can be advantageous in cases where the vehicle to which the driver assistance device 1 is applied is a vehicle with a seat and no enclosed interior space, or a four-wheeled vehicle without a roof, such as an open roof or the like.

[0064] Furthermore, in the embodiment described above, if the vehicle 65 is in motion and the driver mistakes the signal displayed by the more distant traffic light 62 for the signal displayed by the nearest traffic light 61, and therefore the vehicle 65 does not brake even when approaching the position where it should stop, a warning is issued to the driver. However, instead of issuing a warning, or in addition to issuing a warning, the control unit 26 can activate the braking device 25 (see Fig.3) Control the vehicle so that the braking device automatically brakes the vehicle 65. In this way, the vehicle 65 can be braked safely. Therefore, it can be prevented that the vehicle 65 enters the intersection, pedestrian crossing, or the like contrary to the signal indicated by the next traffic light. However, in the case where the vehicle 65 is a motorcycle, there is a risk that automatic braking of the vehicle 65, contrary to the driver's expectations, will cause unstable handling of the vehicle 65. Therefore, in the case where the vehicle 65 is a motorcycle, in order to use the configuration for performing automatic braking, it is necessary to consider the safety of the vehicle 65 during automatic braking.

[0065] In the embodiment described above, a further condition for issuing a warning is that the signal displayed by the nearest of the two or more traffic signals located in front of the vehicle 65 must indicate a prohibition against proceeding straight ahead. Under this condition, a prohibition against proceeding straight ahead may include a stop (a state in which the yellow light is illuminated). In the embodiment described above, a further condition for issuing a warning is that the signal displayed by the more distant of the two or more traffic signals located in front of the vehicle 65 must indicate a permission to proceed or a permission to proceed in a limited direction.Instead of this condition, a condition shall be given which indicates the sign shown by the more distant traffic light sign 62, which gives permission to proceed, permission to proceed in a limited direction, or to stop.

[0066] In the embodiment described above, where the increase in vehicle movement distance attributable to incorrect character recognition is added to the distance between the vehicle and the position where the vehicle is to stop, and relative to the distance obtained by adding the stopping distance, the upper limit for the speed at which a safe stop is possible is also set to a speed corresponding to the stopping distance. However, the present invention is not limited to this. For example, in a case where there is only one object in front of the vehicle, the upper limit for the speed at which a safe stop is possible can be set to a lower value corresponding to a predetermined percentage of the upper limit for the speed at which a safe stop of the vehicle is possible precisely in front of the object.

[0067] In the embodiment described above, if a sound or message is emitted as a warning, the driver can also be informed more precisely that there is a possibility that the driver might mistake the sign displayed by more distant traffic light sign 62 for the sign displayed by the nearest traffic light sign 61. For example, a sound or message ("Don't confuse the more distant sign with the nearest one?") can be emitted.

[0068] Furthermore, the present invention can be applied to various vehicles, such as vehicles with a riding seat, like motorcycles and motor tricycles, and four-wheeled automobiles.

Claims

[1] A driver assistance device (1) for assistance in driving a vehicle (65), comprising: an object recognition unit (31) designed to detect objects in front of the vehicle (65), a vehicle speed detection unit (32) designed to detect the speed of the vehicle (65), and a driver assistance unit (34) designed to issue a warning to a driver of the vehicle (65) when the object detection unit (31) detects that there are two or more traffic light signs (61, 62) in front of the vehicle (65), characterized by , that the driver assistance unit (34) is designed to issue a warning to the driver of the vehicle (65) when the object detection unit (31) detects that a sign indicating a prohibition on proceeding straight ahead is detected by one of the two or more traffic light signs (61, 62) closest to the vehicle (65), and a sign indicating permission to proceed or permission to proceed in a limited direction is detected by at least one more distant traffic light sign (62) that is farther away from the vehicle (65) than the nearest traffic light sign (61), and the speed of the vehicle (65) detected by the vehicle speed detection unit (32) exceeds an upper limit for such a speed at which the vehicle (65) can be stopped at a position where the vehicle (65) can be stopped in accordance with the sign indicated by the nearest traffic light sign (61). wherein the upper limit for the speed is calculated by adding an increase in a vehicle movement distance attributable to a false character recognition to a distance between the vehicle (65) and a position at which the vehicle is to stop. [2] The driver assistance device (1) according to claim 1, wherein, when the object recognition unit (31) detects that there are two or more traffic light signs (61, 62) in front of the vehicle (65), and the sign indicated by the nearest traffic light sign (61) of the two or more traffic light signs (61, 62) indicates a prohibition of driving straight ahead, and the sign indicated by the at least one more distant traffic light sign (62) of the two or more traffic light signs (61, 62) indicates permission to proceed or permission to proceed in a limited direction, and the vehicle speed detection unit (32) detects that the vehicle (65), which is stationary at the position where the vehicle (65) is supposed to stop, is moving forward, the driver assistance unit issues a warning to the driver. [3] The driver assistance device (1) according to claim 1 or 2, wherein the driver assistance unit (34) brakes the vehicle (65) instead of or in addition to issuing the alarm. [4] The driver assistance device (1) according to claim 1, further comprising a road surface condition detection unit (35) configured to detect a condition of a road surface on which the vehicle (65) is driving, wherein the driver assistance unit (34) modifies, on the basis of the condition of the road surface detected by the road surface condition detection unit (35), the upper limit for the speed at which the vehicle (65) can be stopped at the position where the vehicle (65) is to stop. [5] The driver assistance device (1) according to claim 1 or 4, further comprising a weather detection unit (36) configured to detect weather at a location where the vehicle (65) is driving, wherein the driver assistance unit (34) modifies, on the basis of the weather detected by the weather detection unit (36), the upper limit for the speed at which the vehicle (65) can be stopped at the position where the vehicle (65) is to stop. [6] The driver assistance device (1) according to one of claims 1, 2, 4 and 5, further comprising a vibration generation device (22) configured to apply a vibration to the driver, wherein the driver assistance unit (34) performs the application of the vibration to the driver by the vibration generation device (22) as an output of the alarm. [7] The driver assistance device (1) according to any one of claims 1 to 6, wherein a speed function or a data table which stores increases in the vehicle movement distance attributable to the incorrect character recognition in advance in an internal memory.

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