Driving assistance devices

Abstract

To provide a driving support device that can detect highly accurately (more accurately than conventional devices) whether or not a three-dimensional object located to a side of an own vehicle is another vehicle that has excessively approached the own vehicle.SOLUTION: Based on information obtained from an on-vehicle sensor 20, a driving support device 1 detects that there is a driving lane L1 adjacent to a driving lane L0 in which an own vehicle is traveling, and that there are no stationary objects in an area R[n+10] located ahead of the own vehicle in the driving lane L1, and then, in a situation in which the own vehicle is located in a side of the area R[n+10], a three-dimensional object OB is present in the area R[n+10], and a distance Δd between the three-dimensional object OB and the own vehicle is less than a threshold value, controls an alarm device 30 so that a predetermined alarm is issued to occupants of the own vehicle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device that issues a predetermined warning to an occupant of a vehicle when it detects that another vehicle is approaching the vehicle excessively. [Background technology]

[0002] A device has been proposed that has the function of detecting whether or not a three-dimensional object is present to the side of a vehicle (see, for example, Patent Document 1 below). The device in Patent Document 1 (hereinafter referred to as the "conventional device") includes a camera and a processor. The camera photographs an area to the side of the vehicle to obtain an image, and based on the image, detects the distance between the vehicle and the three-dimensional object located to the side of the vehicle. If the distance is less than a threshold, the processor determines that the three-dimensional object is a dangerous vehicle and stores an image of the three-dimensional object in a storage device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-49189 Summary of the Invention

[0004] Conventional devices may judge a three-dimensional object located to the side of the vehicle to be a dangerous vehicle that is approaching the vehicle excessively, even if the three-dimensional object (stationary object) is a stationary object.

[0005] One of the objects of the present invention is to provide a driving assistance device that can detect with high accuracy (more accurately than conventional devices) whether a three-dimensional object located to the side of the vehicle is another vehicle that is approaching excessively close to the vehicle.

[0006] In order to solve the above problems, the driving assistance device (1) of the present invention comprises: an on-board sensor (20) for acquiring information about targets present around the host vehicle (V); a processor (10) for controlling a notification device (30) of the vehicle so as to issue a predetermined warning to an occupant of the vehicle when predetermined conditions (X, Y) for determining that a three-dimensional object located to the side of the vehicle is a vehicle that has come excessively close to the vehicle are met; Equipped with. When the processor detects, based on information acquired from the on-board sensor, that a first driving lane (L1) exists adjacent to the driving lane (L0) in which the host vehicle is traveling, and that there is no stationary object in a predetermined area (R) located ahead of the host vehicle in the first driving lane, and then detects that a three-dimensional object (OB) exists in the predetermined area while the host vehicle is located to the side of the predetermined area, And, The processor determines whether the width (W[n]) of the first driving lane is equal to or greater than a predetermined value (Wth) and the host vehicle is located to the side of the predetermined area, and if the distance (Δd) between the host vehicle and a three-dimensional object present in the predetermined area is less than a first threshold (Δdth1), and When the width of the first driving lane is less than the predetermined value and the host vehicle is located to the side of the predetermined area, and the distance between the host vehicle and a three-dimensional object present in the predetermined area is less than a second threshold value (Δdth2) which is smaller than the first threshold value, It is determined that the predetermined condition is met.

[0007] When a first driving lane exists, a situation is assumed in which there are no stationary objects within a predetermined area diagonally ahead of the host vehicle, and then, when the host vehicle reaches the side of that area, a three-dimensional object is present within that area. In this situation, the three-dimensional object is likely to be another vehicle approaching the host vehicle. The driving assistance device according to the present invention issues an alarm when the distance between the three-dimensional object and the host vehicle is less than a threshold value under this situation. This prevents an alarm from being issued when the host vehicle passes the side of a stationary object. In this way, the driving assistance device can detect with high accuracy (more accurately than conventional devices) whether a three-dimensional object located to the side of the host vehicle is another vehicle approaching excessively close to the host vehicle.

[0009] The driving assistance device according to this aspect estimates that a three-dimensional object in a predetermined area is a four-wheeled vehicle if the width of the first travel lane is equal to or greater than a threshold, and estimates that the three-dimensional object is a two-wheeled vehicle if the width is less than the threshold. If the driving assistance device estimates that the three-dimensional object is a four-wheeled vehicle, it issues an alarm if the distance between the three-dimensional object and the host vehicle (lateral inter-vehicle distance) is less than a first threshold. If the driving assistance device estimates that the other vehicle is a two-wheeled vehicle, it issues an alarm if the lateral inter-vehicle distance is less than a second threshold that is smaller than the first threshold. In this manner, the driving assistance device sets a threshold value (first threshold or second threshold) for the lateral inter-vehicle distance depending on the type of the other vehicle. Here, it is assumed that the driving assistance device is configured to issue an alarm if the lateral inter-vehicle distance is less than the first threshold, regardless of the type of the other vehicle. Under this assumption, if the three-dimensional object were a two-wheeled vehicle, an alarm may be issued even if the lateral inter-vehicle distance is maintained sufficiently large to allow the host vehicle and the two-wheeled vehicle to travel safely (lateral inter-vehicle distance > second threshold). According to the driving assistance device of this aspect, unnecessary warnings such as those described above are suppressed.

[0010] In a driving assistance device according to another aspect of the present invention, The on-board sensor includes a forward camera (22) that can photograph the view in front of the vehicle, including the specified area, to acquire image data, and can obtain the presence or absence of the first driving lane and the width of the first driving lane based on the image data.

[0011] This makes it possible to acquire with relatively high accuracy whether the first driving lane exists and the width of the first driving lane.

[0012] In a driving assistance device according to another aspect of the present invention, The on-board sensor includes a millimeter wave radar (21) that acquires information about a three-dimensional object within the predetermined area, The processor determines whether or not there is a stationary object within the specified area based on information obtained by the forward camera and the millimeter-wave radar.

[0013] This allows the presence or absence of a stationary object to be determined with higher accuracy than when the presence or absence of a stationary object is determined based only on the detection result of a single sensor. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a block diagram of a driving assistance device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing the target area for preliminary judgment and final judgment. [Figure 3] FIG. 3 is a flowchart of a first program for realizing the other vehicle approach warning function. [Figure 4] FIG. 4 is a flowchart of a second program for realizing the other vehicle approach warning function. DETAILED DESCRIPTION OF THE INVENTION

[0015] (Summary) A driving assistance device 1 according to one embodiment of the present invention is mounted on a vehicle V (hereinafter referred to as "host vehicle") equipped with an automatic driving function. The driving assistance device 1 has a function (other vehicle approach warning function) of issuing a predetermined warning to the occupants of the host vehicle when it is determined that a three-dimensional object located to the side of the host vehicle is another vehicle that has come excessively close to the host vehicle in a situation where the automatic driving function is disabled (a situation where the driver is actively performing driving operations).

[0016] (Specific configuration) As shown in FIG. 1, the driving assistance device 1 includes a driving assistance ECU 10, an in-vehicle sensor 20, and a notification device 30.

[0017] The driving assistance ECU 10 includes a microcomputer equipped with a CPU 10a, a ROM 10b (flash ROM), a RAM 10c, etc. The driving assistance ECU 10 is connected to other ECUs provided in the vehicle via a CAN (Controller Area Network).

[0018] The on-board sensor 20 includes a front sensor and a side sensor that acquire information about targets located in front of and to the sides of the vehicle, respectively. Specifically, the on-board sensor 20 includes a millimeter-wave radar 21 and a front camera 22 as front sensors. The on-board sensor 20 also includes a sonar 23 as a side sensor.

[0019] The millimeter-wave radar 21 includes a transmitter / receiver and a signal processor. The transmitter / receiver emits millimeter-wave band radio waves (hereinafter referred to as "millimeter waves") ahead of the vehicle and receives millimeter waves (reflected waves) reflected by a three-dimensional object OB located within the emission range. The signal processor detects the distance between the vehicle and the three-dimensional object OB, the position (direction) of the three-dimensional object OB relative to the vehicle, the speed of the three-dimensional object OB, etc., based on the time from when the transmitter / receiver emits the millimeter waves to when the reflected waves are received, the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation of the reflected waves, etc., and transmits the detection results to the driving assistance ECU 10.

[0020] As shown in Figure 2, area A, in which the millimeter-wave radar 21 can detect a three-dimensional object OB with high accuracy, has an apex at the position of the millimeter-wave radar 21 and is fan-shaped in a plan view, spreading out from the apex to the front of the vehicle. A line segment connecting the apex of the fan (the position of the front sensor) that defines area A to the midpoint of the arc substantially coincides with the longitudinal axis of the vehicle. Area A includes area A0 on the driving lane L0 in which the vehicle is traveling, and area A1 on the driving lane L1 adjacent to driving lane L0. Therefore, the millimeter-wave radar 21 can acquire information (such as relative position and speed) about a three-dimensional object OB located diagonally ahead of the vehicle.

[0021] The front camera 22 includes an imaging device and an image analysis device. The imaging device is, for example, a digital camera with a built-in imaging element such as a CCD (charge coupled device). The imaging device is located at the front of the vehicle and faces forward. The imaging device captures images of the front view of the vehicle at a predetermined frame rate to acquire image data. The angle of view of the front camera 22 includes an area A1. The imaging device provides the image data to the image analysis device. The image analysis device analyzes the acquired image data and recognizes the type of three-dimensional object OB (such as another vehicle or a sign indicating a construction zone) located in front of the vehicle from the image. The image analysis device also analyzes the image data to recognize the presence or absence of a travel lane L1 (a travel lane adjacent to the travel lane L0 in which the vehicle is traveling), the width W (transverse length) of the travel lane L1, etc. The image analysis device transmits the above recognition results to the driving assistance ECU 10.

[0022] Here, when the image analysis device recognizes the existence of a driving lane L1, it sets multiple rectangular regions R[0], R[1], R[2], etc. that are offset in the longitudinal direction of the driving lane L1 in a planar view. The width W[n] of each region R[n] is the same as the width of the driving lane L1. The longitudinal length L of the region R[n] is equal to the overall length of the vehicle. Regions R[0], R[1], R[2], etc., R[max] are arranged in this order from the start of the driving lane L1 (the region closest to the vehicle at the time the image analysis device recognizes the existence of the driving lane L1) to the end (the end in the direction moving away from the vehicle). The longitudinal offset between two adjacent regions R[n] and R[n+1] is, for example, 1 meter, and these two regions partially overlap. Note that Figure 2 shows an example in which a driving lane L1 is located to the right of the driving lane L0 in which the vehicle is traveling, but even if the driving lane L1 is located to the left of the driving lane L0, multiple regions R[0], R[1], ... are set on the driving lane L1.

[0023] The image analysis device analyzes the image data to determine whether the host vehicle is located to the side of the region R[n] (whether the center of gravity of the host vehicle is located to the side of the center C of the region R[n]), and transmits the determination result to the driving assistance ECU 10. Note that when the host vehicle is located to the side of the region R[n], the region R[n] and its neighboring regions (several regions in front of the region R[n]) are located outside the angle of view of the imaging device. At this point, the image analysis device can recognize, for example, the regions R[n+5] to R[n+20] with high accuracy. When the region R[n+5] is located at a predetermined position in the captured image, the image analysis device recognizes that the host vehicle is located to the side of the region R[n].

[0024] Furthermore, the image analysis device calculates the direction and distance relative to the host vehicle of the region R[n+10] that can be recognized with high accuracy when the host vehicle is located to the side of the region R[n], and transmits the calculation result to the driving assistance ECU 10. Furthermore, when the image analysis device detects the end of the driving lane L1, it transmits the recognition result of the region R[max] that is closest to the end ("max", which is the index of the end region) to the driving assistance ECU 10. Note that the range of the region that the image analysis device can recognize with high accuracy is an example, and the range may expand or contract depending on the performance of the imaging device.

[0025] Incidentally, when the host vehicle is located to the side of the area R[n], the area R[n+10] is included in the area A1 of the detectable area A of the millimeter-wave radar 21. Therefore, in a situation where the host vehicle is located to the side of the area R[n], the millimeter-wave radar 21 can acquire information about the three-dimensional object OB located within the area R[n+10] (for example, the shape, type, speed v0, etc. of the three-dimensional object OB).

[0026] As shown in FIG. 1, the sonar 23 includes transceivers 23La, 23Ra and 23Lb, 23Rb. The sonar 23 further includes a signal analyzer. The transceiver 23La is located at the front of the left side of the vehicle and faces leftward. The transceiver 23Ra is located at the front of the right side of the vehicle and faces rightward. The transceiver 23Lb is located at the rear of the left side of the vehicle and faces leftward. The transceiver 23Rb is located at the rear of the right side of the vehicle and faces rightward. Each transceiver intermittently emits ultrasonic waves and receives ultrasonic waves (reflected waves) reflected by a three-dimensional object OB. Each transceiver then provides a signal (reflected wave signal) representing the received reflected waves to the signal analyzer.

[0027] The signal analysis unit analyzes the reflected wave signals received from the respective transmitters and receivers to calculate the position (distance and direction) of the three-dimensional object OB relative to the vehicle, and then transmits the calculation result to the driving assistance ECU 10.

[0028] The notification device 30 includes an image display device and an audio device. The notification device 30 is incorporated, for example, in the instrument panel of the vehicle. The image display device displays a predetermined image (for example, an image indicating the presence of an approaching vehicle) in accordance with an image display command received from the driving assistance ECU 10. The audio device reproduces a predetermined warning sound (beep sound) in accordance with an audio reproduction command received from the driving assistance ECU 10.

[0029] (Other vehicle approach warning function) As will be described in detail later, the driving assistance device 1 issues a predetermined warning to the occupants of the vehicle when predetermined conditions (hereinafter referred to as "approach warning initiation conditions") are met for determining that a three-dimensional object located to the side of the vehicle is another vehicle that has come excessively close to the vehicle.

[0030] A situation may be assumed in which there are no stationary objects in area R diagonally ahead of the host vehicle in travel lane L1 adjacent to travel lane L0 in which the host vehicle is traveling, and then, when the host vehicle reaches the side of area R, a three-dimensional object OB is present in area R. In this situation, the three-dimensional object OB is present in area R where there are no stationary objects, and it is highly likely that the three-dimensional object OB is another vehicle approaching the host vehicle. Therefore, the driving assistance device 1 issues an alarm to the occupants of the host vehicle when the distance Δd (lateral inter-vehicle distance) between the three-dimensional object OB (an object presumed to be another vehicle) and the host vehicle is relatively small. That is, the driving assistance device 1 issues an alarm when the distance Δd is less than a threshold Δdth (the minimum inter-vehicle distance required for the host vehicle and the other vehicle to travel safely). However, the minimum inter-vehicle distance between a two-wheeled vehicle and the host vehicle is smaller than the minimum inter-vehicle distance between a four-wheeled vehicle and the host vehicle. Therefore, the driving assistance device 1 determines whether to issue an alarm not only based on the distance Δd but also based on the type of other vehicle (two-wheeled vehicle or four-wheeled vehicle).

[0031] Specifically, as described below, when the host vehicle is located to the side of the region R[n], the driving assistance ECU 10 determines whether or not there is a stationary object in the region R[n+10] (performs a preliminary determination). Then, when the host vehicle travels and reaches the side of the region R[n+10], the driving assistance ECU 10 determines whether or not there is a three-dimensional object OB located in the region R[n+10] (performs a final determination). In the following description, the result of the preliminary determination is referred to as the "preliminary determination result," and the result of the final determination is referred to as the "final determination result." The driving assistance ECU 10 then determines that the approach warning start condition is met when the condition X related to the preliminary determination result and the final determination result is met, and the condition Y related to the width W of the traveling lane L1 and the distance Δd between the host vehicle and the three-dimensional object OB is met.

[0032] Specifically, when the driving assistance ECU 10 detects, based on information acquired from the forward sensor (forward camera 22), that the host vehicle is located to the side of any one of the regions R[n] among the regions R[0], R[1], ..., R[max-10], the driving assistance ECU 10 executes the following preliminary determination. That is, when the host vehicle is located to the side of the region R[n] (the center of gravity of the host vehicle is to the side of the center C of the region R[n]), the driving assistance ECU 10 acquires information from the forward sensor (millimeter-wave radar 21 and forward camera 22) and determines, based on the information, whether or not a stationary object (a three-dimensional object OB with a speed v0 of "0") is present in the region R[n+10] ("stationary object present" or "stationary object not present"). The driving assistance ECU 10 stores the determination result (preliminary determination result) in the RAM 10c (or ROM 10b) as the preliminary determination result PD[n+10] for the region R[n+10]. If the driving assistance ECU 10 determines that no stationary object exists in the region R[n+10], it acquires the width W[n+10] of the region R[n+10] (the width of the driving lane L1) based on the information acquired from the front camera 22. Then, the driving assistance ECU 10 stores the width W[n+10] in the RAM 10c (or ROM 10b) in addition to the preliminary determination result PD[n+10].

[0033] Furthermore, when the driving assistance ECU 10 detects, based on information acquired from the forward sensor (forward camera 22), that the host vehicle is located to the side of any one of the regions R[n] among the regions R

[10] , R

[11] , ..., R[max], the driving assistance ECU 10 reads out the preliminary determination result PD[n] for the region R[n] (i.e., the result of the preliminary determination performed at a point "10 meters" before the current position) from the RAM 10c (or ROM 10b). If the preliminary determination result PD[n] is "no stationary object," the driving assistance ECU 10 executes the following final determination. That is, based on information acquired from the sonar 23, the driving assistance ECU 10 determines whether or not a three-dimensional object OB exists in the region R[n] ("three-dimensional object present" or "three-dimensional object not present"). If the final determination result is "three-dimensional object present," the driving assistance ECU 10 determines that the condition X is satisfied. In this way, condition X is met when the preliminary determination result PD[n] for region R[n] is "no stationary object" and the final determination result FD[n] is "three-dimensional object present." On the other hand, condition X is not met when the preliminary determination result PD[n] is "stationary object present" or when the final determination result FD[n] is "no three-dimensional object."

[0034] When the driving assistance ECU 10 determines that the condition X is satisfied under a condition in which the host vehicle is located to the side of any one of the regions R[n] (i.e., a region for which preliminary determination has been performed) among the regions R

[10] , R

[11] , ..., R[max], the driving assistance ECU 10 acquires the distance Δd between the three-dimensional object OB and the side of the host vehicle based on information acquired from the sonar 23. Furthermore, the driving assistance ECU 10 reads the width W[n] (the width of the driving lane L1) from the RAM 10c (or ROM 10b). The driving assistance ECU 10 determines whether the width W[n] is equal to or greater than a threshold Wth (e.g., 3 meters). If the driving assistance ECU 10 determines that the width W[n] is equal to or greater than the threshold Wth, it estimates that the three-dimensional object OB is a four-wheeled vehicle. In this case, the driving assistance ECU 10 determines whether the distance Δd is less than a threshold Δdth1 (e.g., 1 meter). When the driving assist ECU 10 determines that the distance Δd is less than the threshold value Δdth1, it determines that the condition Y is met. On the other hand, when the driving assist ECU 10 determines that the width W[n] is less than the threshold value Wth, it estimates that the three-dimensional object OB is a two-wheeled vehicle. In this case, the driving assist ECU 10 determines whether the distance Δd is less than a threshold value Δdth2 (e.g., 50 centimeters) that is less than the threshold value Δdth1. When the driving assist ECU 10 determines that the distance Δd is less than the threshold value Δdth2, it determines that the condition Y is met. In this way, the condition Y is met when "the width W[n] is equal to or greater than the threshold value Wth and the distance Δd is less than the threshold value Δdth1" or "the width W[n] is less than the threshold value Wth and the distance Δd is less than the threshold value Δdth2."

[0035] The driving assistance ECU 10 determines that the proximity warning start condition is met when it determines that condition X is met and condition Y is met. When the driving assistance ECU 10 determines that the proximity warning start condition is met, it controls the notification device 30 so that a predetermined warning is issued to the occupants of the vehicle. Specifically, the driving assistance ECU 10 causes the image display device of the notification device 30 to display a predetermined image and causes the audio device of the notification device 30 to play a predetermined warning sound (beep sound). When a predetermined time has elapsed since the start of the warning, the driving assistance ECU 10 ends the warning.

[0036] Next, with reference to FIGS. 3 and 4, the program PR1 and the program PR2 executed by the CPU 10a (hereinafter simply referred to as "CPU") to realize the other vehicle approach warning function will be described.

[0037] When the CPU detects the driving lane L1 based on information acquired from the forward sensor while the host vehicle is traveling forward, the CPU starts executing the programs PR1 and PR2 shown in Figures 3 and 4. Note that while the CPU is executing the programs PR1 and PR2, if the image analysis device of the forward camera 22 detects the area R[max] (i.e., the end of the driving lane L1), it sends "max", which is the identification information (index) of the area R[max], to the CPU.

[0038] (Program PR1) The CPU starts execution of the program PR1 from step 100 and proceeds to step 101.

[0039] The CPU executes initialization processing in step 101. Specifically, the CPU sets "n", which is an index for selecting (specifying) one region R[n] from among regions R[0], R[1], . . . , R[max], to "0". Next, the CPU proceeds to step 102.

[0040] In step 102, the CPU determines whether or not the host vehicle has reached the side of area R[n] based on information acquired from the forward sensor. If the CPU determines that the host vehicle has reached the side of area R[n] (102: Yes), the CPU proceeds to step 103. On the other hand, if the CPU does not determine that the host vehicle has reached the side of area R[n] (101: No), the CPU returns to step 102. That is, the CPU repeats step 102 until the host vehicle reaches the side of area R[n].

[0041] In step 103, the CPU executes a preliminary determination for the region R[n+10]. That is, the CPU acquires a preliminary determination result PD[n+10] (presence or absence of a stationary object (and width W[n])) for the region R[n+10] based on information acquired from the millimeter-wave radar 21 and the forward camera 22. Next, the CPU proceeds to step 104.

[0042] The CPU stores the preliminary determination result PD[n+10] (and the width W[n]) in the RAM 10c (or ROM 10b) in step 104. Next, the CPU proceeds to step 105.

[0043] In step 105, the CPU adds "1" to "n". That is, the CPU updates the target of preliminary determination to the next region R[n+11]. Next, the CPU proceeds to step .

[0044] In step 106, the CPU determines whether the end of the driving lane L1 has been detected. That is, the CPU determines whether the index "max" of the area R[max] has been acquired from the front camera 22. If the CPU determines that the end of the driving lane L1 has been detected (106: Yes), the CPU proceeds to step 107. On the other hand, if the CPU does not determine that the end of the driving lane L1 has been detected (106: No), the CPU returns to step 102.

[0045] In step 107, the CPU determines whether "n," which is the index of the region R[n] to be subjected to preliminary detection, is greater than "max," which is the index of the region R[max] at the end of the driving lane L1. If "n" is greater than "max" (107: Yes), the CPU determines that there is no region R[n] to be subjected to preliminary detection, and proceeds to step 108, where it terminates execution of program PR1. On the other hand, if [n] is equal to or less than [max] (107: No), the CPU determines that there is a region R[n] to be subjected to preliminary detection, and returns to step 102.

[0046] (Program PR2) The CPU starts execution of the program PR2 from step 200 and proceeds to step 201.

[0047] The CPU executes initialization processing in step 201. Specifically, the CPU sets "n", which is an index for selecting (specifying) one region R[n] from among regions R[0], R[1], ..., R[max], to "0". Next, the CPU proceeds to step 202.

[0048] In step 202, the CPU determines whether or not the host vehicle has reached the side of region R[n] based on information acquired from the forward sensor. If the CPU determines that the host vehicle has reached the side of region R[n] (202: Yes), the CPU proceeds to step 203. On the other hand, if the CPU does not determine that the host vehicle has reached the side of region R[n] (201: No), the CPU returns to step 202. That is, the CPU repeats step 202 until the host vehicle reaches the side of region R[n].

[0049] As described above, the CPU executes the program PR1 to sequentially perform preliminary determinations for the region R

[10] and each region ahead of it (R

[11] , R

[12] , ...), but does not perform preliminary determinations for the regions R[0] to R[9]. Therefore, in step 203, the CPU determines whether or not a preliminary determination has been performed for the region R[n] on the side of the host vehicle (whether "n" is 10 or greater). If the CPU determines that a preliminary determination has been performed for the region R[n] (n≧10) (203: Yes), the CPU proceeds to step 204. On the other hand, if the CPU does not determine that a preliminary determination has been performed for the region R[n] (203: No), the CPU proceeds to step 213, which will be described later.

[0050] In step 204, the CPU reads out the preliminary detection result PD[n] for the region R[n] on the side of the vehicle from the RAM 10c (or ROM 10b).

[0051] In step 205, the CPU determines whether the preliminary detection result PD[n] indicates "no stationary object." If the CPU determines that the preliminary detection result PD[n] indicates "no stationary object" (205: Yes), the CPU proceeds to step 206. On the other hand, if the CPU does not determine that the preliminary detection result PD[n] indicates "no stationary object" (205: No), the CPU proceeds to step 213, which will be described later.

[0052] The CPU executes a final determination for the region R[n] in step 206. That is, the CPU determines whether or not a three-dimensional object OB exists in the region R[n] based on the information acquired from the sonar 23.

[0053] In step 207, the CPU determines whether the final determination result FD[n] for the region R[n] is "three-dimensional object present." If the CPU determines that the final determination result FD[n] is "three-dimensional object present" (207: Yes), the CPU proceeds to step 208. On the other hand, if the CPU does not determine that the final determination result FD[n] is "three-dimensional object present" (208: No), the CPU proceeds to step 213.

[0054] In step 208, the CPU acquires the distance Δd between the three-dimensional object OB and the side of the vehicle from the sonar 23, and reads out W[n] from the RAM 10c (or ROM 10b).

[0055] In step 209, the CPU determines whether the width W[n] is equal to or greater than the threshold value Wth. If the CPU determines that the width W[n] is equal to or greater than the threshold value Wth (209: Yes), the CPU proceeds to step 210. On the other hand, if the CPU does not determine that the width W[n] is equal to or greater than the threshold value Wth (209: No), the CPU proceeds to step 211.

[0056] In step 210, the CPU determines whether the distance Δd is less than the threshold value Δdth1. If the CPU determines that the distance Δd is less than the threshold value Δdth1 (210: Yes), the CPU proceeds to step 212. On the other hand, if the CPU does not determine that the distance Δd is less than the threshold value Δdth1 (210: No), the CPU proceeds to step 213.

[0057] The CPU determines whether the distance Δd is less than the threshold value Δdth2 (<Δdth1) in step 211. If the CPU determines that the distance Δd is less than the threshold value Δdth2 (211: Yes), the CPU proceeds to step 212. On the other hand, if the CPU does not determine that the distance Δd is less than the threshold value Δdth2 (210: No), the CPU proceeds to step 213.

[0058] In step 212, the CPU controls the alarm device 30 to issue a predetermined alarm to the occupants of the vehicle.

[0059] In step 213, the CPU adds "1" to "n". That is, the CPU updates the target of final determination to region R[n+1]. Next, the CPU proceeds to step 214.

[0060] In step 214, the CPU determines whether the end of the driving lane L1 has been detected. That is, the CPU determines whether the index "max" of the area R[max] has been acquired from the front camera 22. If the CPU determines that the end of the driving lane L1 has been detected (214: Yes), the CPU proceeds to step 215. On the other hand, if the CPU does not determine that the end of the driving lane L1 has been detected (214: No), the CPU returns to step 202.

[0061] In step 215, the CPU determines whether "n," which is the index of the region R[n] to be subjected to the final determination, is greater than "max," which is the index of the region R[max] at the end of the driving lane L1. If "n" is greater than "max" (215: Yes), the CPU determines that there is no region R[n] to be subjected to the final determination, and proceeds to step 216, where it terminates execution of program PR2. On the other hand, if [n] is equal to or less than [max] (215: No), the CPU determines that there is a region R[n] to be subjected to the final determination, and returns to step 202.

[0062] In step 216, the CPU ends the execution of the program PR2.

[0063] (effect) When a driving lane L1 exists, it is assumed that there is no stationary object in the area diagonally ahead of the host vehicle, and then, when the host vehicle reaches the side of that area, a three-dimensional object OB is present in that area. In this situation, the three-dimensional object OB is likely to be another vehicle approaching the host vehicle. In this situation, the driving assistance device 1 issues an alarm if the distance Δd is relatively small. This prevents an alarm from being issued when the host vehicle passes the side of a stationary object. In this way, the driving assistance device 1 can detect with high accuracy (more accurately than conventional devices) whether a three-dimensional object located to the side of the host vehicle is another vehicle that is approaching the host vehicle excessively.

[0064] Furthermore, the driving assistance device 1 estimates that the three-dimensional object OB is a four-wheeled vehicle if the width W[n] is equal to or greater than the threshold Wth, and estimates that the three-dimensional object OB is a two-wheeled vehicle if the width W[n] is less than the threshold Wth. If the driving assistance device 1 estimates that the three-dimensional object OB is a four-wheeled vehicle, it issues an alarm if the distance Δd is less than the threshold Δdth1. If the driving assistance device 1 estimates that the three-dimensional object OB is a two-wheeled vehicle, it issues an alarm if the distance Δd is less than the threshold Δdth2, which is smaller than the threshold Δdth1. In this manner, the driving assistance device 1 sets the threshold Δdth (Δdth1 or Δdth2) depending on the type of other vehicle. Here, it is assumed that the driving assistance device is configured to issue an alarm if the distance Δd is less than the threshold Δdth1, regardless of the type of other vehicle. Under this assumption, if the three-dimensional object OB is a two-wheeled vehicle, there is a risk that an alarm will be issued even if the distance Δd is maintained to a level that allows the host vehicle and the two-wheeled vehicle to travel safely (Δd > Δdth2). According to this embodiment, unnecessary alarms such as those described above are suppressed.

[0065] The present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

[0066] (Variation 1) The on-board sensor 20 may include a navigation system 24 (see FIG. 1). The navigation system 24 receives GPS signals from multiple satellites and detects the current location (latitude and longitude) of the vehicle based on the received GPS signals. The navigation system 24 also stores map data representing a map. The map data includes road information representing roads (e.g., the number of lanes constituting the road, the width of each lane, etc.). Based on the information obtained from the navigation system 24, the driving assistance ECU 10 may obtain information such as the presence or absence of a lane L1, the width W[n] of the region R[n], and the relative positions (direction and distance) of the vehicle with respect to the regions R[n] and R[n+10].

[0067] (Variation 2) The manner in which the warning is given to the occupants of the vehicle is not limited to the manner in the above embodiment, and for example, the warning may be given by vibrating the steering wheel. [Explanation of symbols]

[0068] 1... driving assistance device, 10... driving assistance ECU, 20... in-vehicle sensor, 30... alarm device

Claims

1. an on-board sensor that acquires information about targets present around the vehicle; a processor that controls a notification device of the host vehicle so as to issue a predetermined warning to an occupant of the host vehicle when a predetermined condition for determining that a three-dimensional object located to the side of the host vehicle is another vehicle that has come excessively close to the host vehicle is met; A driving assistance device comprising: The processor detects, based on information acquired from the on-board sensor, that there is a first driving lane adjacent to the driving lane in which the host vehicle is traveling, that there is no stationary object in a predetermined area located ahead of the host vehicle in the first driving lane, and then detects that there is a three-dimensional object in the predetermined area while the host vehicle is located to the side of the predetermined area, and that the distance between the three-dimensional object and the host vehicle is less than a threshold value, When the width of the first travel lane is equal to or greater than a predetermined value and the host vehicle is located to the side of the predetermined area, the distance between the host vehicle and a three-dimensional object present in the predetermined area is less than a first threshold value; and When the width of the first driving lane is less than the predetermined value and the host vehicle is located to the side of the predetermined area, the distance between the host vehicle and a three-dimensional object present in the predetermined area is less than a second threshold value that is smaller than the first threshold value, and determining that the predetermined condition is met.

2. The driving assistance device according to claim 1, The on-board sensor is a driving assistance device that includes a forward camera that photographs the view in front of the vehicle including the specified area to acquire image data, and is capable of acquiring the presence or absence of the first driving lane and the width of the first driving lane based on the image data.

3. The driving assistance device according to claim 2, the on-board sensor includes a millimeter wave radar that acquires information about a three-dimensional object within the predetermined area; The processor determines whether or not there is a stationary object within the specified area based on information acquired by the forward camera and the millimeter-wave radar.

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