Vehicle driving assistance control device

Abstract

Vehicle driving assistance control device (2), comprising: a first environment detection device (3) for detecting lane line information relating to a preceding lane, based on image information, a second environment sensing device (4) for detecting ahead three-dimensional object information, based on transmitted and received radio wave information, a vision range estimation device (51) for estimating the vision range (Lv) of a driver based on lane line information, wherein a vision range estimation unit (51) previously sets a human average visual contrast value for detecting a lane line as a limit value and, as the driver's vision range (Lv), estimates a distance to a detected lane line with a contrast value higher than the limit value, a determining device (52) for determining whether the detected three-dimensional object is outside the driver's field of vision (Lv), a collision possibility determination device (54; 55) for determining the possibility of a collision between the detected three-dimensional object and the vehicle (1), and a collision prevention control device (54; 55) for performing at least one action based on a notification to the driver and an application of automatic braking according to the possibility of a collision of the detected three-dimensional object with the vehicle (1) when the detected three-dimensional object is outside the driver's field of vision (Lv).

Description

[0001] The present invention relates to a vehicle driving assistance control device for performing a warning and automatic braking in order to prevent a collision with a three-dimensional object located in front of a vehicle.

[0002] In recent years, numerous types of vehicle assistance control devices have been developed and implemented to detect three-dimensional objects, such as vehicles and obstacles in front of them, using cameras, radar, or similar technologies, and to prevent collisions with these objects. In such a vehicle assistance control device, highly accurate detection of a three-dimensional object directly leads to precise execution of the vehicle assistance control. For example, a vehicle environment monitoring device disclosed in the Japanese unexamined patent application publication JP 2003-217099A calculates the position of an object based on information in a captured image and also calculates the object's position based on a reflected wave of an emitted radio wave.The device then calculates an observation position, obtained as a result of observation based on both calculated positions, and determines the probability that the object in front of the vehicle will approach the vehicle at a predetermined distance or less. If the probability is determined to be high, this is communicated to the driver.

[0003] However, such a vehicle assistance control device for preventing a collision has a major problem with regard to the assistance technology, namely the difficulty of determining with regard to an implementation, that is, how the necessary information is extracted, presented and controlled when required by the driver.More precisely, even if a three-dimensional object, such as an obstacle in front of the vehicle, is detected with a high degree of accuracy, as in the vehicle environment monitoring device described above and disclosed in JP 2003-217 099 A, there is a disadvantage, which is as follows: if a hazard of which the driver is already aware is communicated as a warning or subjected to a control signal to a greater extent than necessary, the driver becomes accustomed to such a warning or control signal, and this can lead to a delayed reaction when a hazard is actually imminent. Alternatively, the driver may be disturbed or annoyed by the warning or control signal and may deactivate the driving assistance function. This results in the driving assistance control device being unable to perform its function.

[0004] Another vehicle assistance control device is known from DE 10 2009 034 386 A1.

[0005] The present invention was made in view of the circumstances described above and is based on the technical problem or objective of providing a vehicle driving assistance control device that is suitable for carrying out collision prevention control in a suitable manner, such as a notification to a driver and braking with respect to a three-dimensional object such as an obstacle and / or an oncoming vehicle, which can be assumed to have not been detected by the driver.

[0006] A vehicle driving assistance control device according to one aspect of the present invention comprises: a first environment detection device for detecting lane line information relating to an upcoming lane based on image information; a second environment detection device for detecting information relating to an upcoming three-dimensional object based on transmitted and received radio wave information; a field of view estimation device for estimating the field of view of a driver based on the lane line information, wherein a field of view estimation unit first sets a human average visual contrast value for detecting a lane line as a limit value and, as the field of view of the driver, estimates a distance to a detected lane line with a contrast value higher than the limit value; a determination device for determining,whether the detected three-dimensional object is outside the driver's field of vision, a collision possibility determination device for determining the possibility of a collision between the detected three-dimensional object and the vehicle, and a collision prevention control device for executing at least one notification to the driver and applying automatic braking according to the possibility of a collision between the detected three-dimensional object and the vehicle when the detected three-dimensional object is outside the driver's field of vision.

[0007] The invention will be further explained below with reference to an exemplary embodiment in relation to the drawings in which Fig. 1 is a schematic configuration representation showing a vehicle driving assistance control device according to an embodiment of the present invention, which is attached to a vehicle, Fig. 2 is a functional block diagram showing a control unit according to the embodiment of the present invention, Fig. 3 is a flowchart showing a vehicle driving assistance control program according to the embodiment of the present invention, Fig. 4 is a flowchart showing a first collision prevention control subroutine according to the embodiment of the present invention, Fig. 5 is a flowchart showing a second collision prevention control subroutine according to the embodiment of the present invention, Fig. 6 is a representation that describes a first collision prevention control system according to the embodiment of the present invention and Fig. Figure 7 is a representation that describes a second collision prevention control system according to the embodiment of the present invention.

[0008] An embodiment of the present invention is described below with reference to the drawings.

[0009] In Fig. In this invention, a vehicle 1, such as an automobile, has a driving assistance control device 2. The driving assistance control device 2 mainly comprises a stereo camera unit 3, which serves as the first environment detection device according to the present invention, and a millimeter-wave radar unit 4, which serves as the second environment detection device, as well as a control unit 5. The driving assistance control device 2 is connected to various types of sensors, such as a vehicle speed sensor 6 for detecting the vehicle speed V0 of the vehicle 1, a steering angle sensor 7 for detecting a steering angle θH, and a road surface µ estimator 8 for estimating a coefficient of friction (road surface µ) of the road surface. The control unit 5 outputs a control signal to a warning lamp 9 and to a brake drive unit 10, if required.

[0010] The stereo camera unit 3 includes a stereo camera 31 and a first environment detection unit 32 for processing signals from the stereo camera 31.

[0011] The stereo camera 31, as a stereo-optical system, includes, for example, a pair (left and right) CCD cameras with semiconductor image sensors such as charge-coupled devices (CCDs). The CCD cameras forming the stereo camera 31 are mounted at a predetermined distance from each other in the front sections of the roof of a passenger compartment of the vehicle 1. They capture stereo images of external objects from different viewing angles and output the captured image information to the first environment detection unit 32. The first environment detection unit 32 receives the image information from the stereo camera 31 and determines the vehicle's lane by recognizing lane markings in front of the vehicle and the like.The first environment detection unit 32 processes the image information from the stereo camera 31, for example, as follows: the first environment detection unit 32 generates distance information for a pair (right and left) images (stereo images) obtained by recording the environment in front of the subject vehicle 1 in the direction of travel with the stereo camera 31, using a difference between corresponding positions in the images according to a principle of triangulation. The first environment detection unit 32 first divides the reference image (for example, the right image) into small regions, compares the luminance or color pattern of each small region with that of the comparison image in order to find a corresponding region in the comparison image, and obtains a distance distribution over the entire reference image.The first environmental detection unit 32 also checks the luminance difference between adjacent pixels for each pixel on the reference image, extracts pixels with luminance differences greater than a threshold (contrast threshold) as edges, and adds distance information to the extracted pixels (edges) to generate a distribution image (distance image) of the edges. Subsequently, the first environmental detection unit 32 performs, for example, a well-known grouping process with respect to the distance image and carries out a pattern matching with various types of predefined templates to detect the lane markings in front of the vehicle. This lane marking detection is continuously monitored via corresponding individual images.When the lane line is detected, the first environment detection unit 32 also stores the lane width W from the position coordinates of the right and left lane lines and the lateral position of vehicle 1 within the lane (the distance of vehicle 1 to the left lane line and the distance of vehicle 1 to the right lane line) as lane line data. For a lane line, based on luminance and contrast in the image information provided by the stereo camera 31, other than the lane line described above—for example, a lane line segment that is interrupted for some reason and a lane line of vehicle 1's lane that is assumed to still exist—the first environment detection unit 32 estimates the lane line obtained from the image information of the stereo camera 31 by further extending it to estimate the coordinate data.The estimated coordinate data of the lane line can be obtained using map data or characteristic curve data and the like from a navigation system, which is not shown. The lane line information obtained by the stereo camera unit 3 is then output to the control unit 5.

[0012] The millimeter wave radar unit 4 includes a millimeter wave transmission and reception unit 41 and a second environment detection unit 42 for processing a signal output by the millimeter wave transmission and reception unit 41.

[0013] The millimeter wave transmission and reception unit 41 is provided at the front end of the vehicle 1 and is configured to transmit a predetermined millimeter wave (for example, a radio wave from 30 GHz to 100 GHz) forward in front of the vehicle and to receive the reflected millimeter wave in order to pass the transmitted and received data to the second environment detection unit 42.

[0014] The second environmental sensing unit 42 detects a three-dimensional object by processing the transmitted and received data output by the millimeter-wave transmission-receiving unit 41, as follows: the second environmental sensing unit 42 measures a relative distance from the vehicle 1 to a target based on a time interval between the time the transmission wave was reflected by the target and the time the transmission wave returned. Subsequently, an area in which the same distance value continuously appears, as well as the size (width) and coordinate data of a three-dimensional object, are extracted from the distribution state of the distance value.For each extracted three-dimensional object, the distance from vehicle 1 is derived, and the three-dimensional object closest to vehicle 1 is selected as the target three-dimensional object for control. The following values ​​are then calculated for this target three-dimensional object: a distance Lf from vehicle 1 to the target three-dimensional object, a relative velocity VOF between vehicle 1 and the target three-dimensional object (change in distance Lf over time), a velocity Vf of the target three-dimensional object (vehicle velocity V0 + VOF), and a deceleration velocity af. These three-dimensional object information elements are then output to control unit 5 with respect to the target three-dimensional object.

[0015] The control unit 5 receives the lane line information regarding the lane from the first environment detection unit 32 of the stereo camera unit 3, receives the three-dimensional object information regarding the target three-dimensional object from the second environment detection unit 42 of the millimeter wave radar unit 4, receives the vehicle speed V0 from the vehicle speed sensor 6, receives the steering angle θH from the steering angle sensor 7 and receives the road surface µ (coefficient of friction of the road surface) from the road surface µ estimating device 8.

[0016] The control unit 5 then estimates the driver's field of vision based on the lane line information derived from the input information above, determines whether the target three-dimensional object is outside the driver's field of vision, and determines the possibility of a collision between the target three-dimensional object and the vehicle 1. If the target three-dimensional object is outside the driver's field of vision, the control unit 5 performs at least one of the following actions: either notifying the driver or applying automatic braking, depending on the possibility of a collision with the vehicle 1.

[0017] As in Fig. As shown in Figure 2, the control unit 5 mainly comprises a visibility range estimation unit 51, a control determination unit 52, an oncoming vehicle determination unit 53, a first collision prevention control unit 54, a second collision prevention control unit 55, a warning control unit 56 and a brake control unit 57.

[0018] The vision range estimation unit 51 receives lane line information from the first environment detection unit 32, estimates the driver's vision range Lv, and then transmits this value to the control determination unit 52. The driver's vision range Lv is estimated, for example, as follows: a human average contrast value for recognizing the lane on the road surface is predefined as a limit value through testing. The vision range estimation unit 51 compares this limit value with the lane line information received from the first environment detection unit 32 (distance information in front of the lane line). The furthest distance of the lane line detected with a contrast value higher than the limit value is then estimated as the driver's vision range Lv.The field of view estimation unit 51 thus serves as the field of view estimation device according to the present invention.

[0019] The control determination unit 52 receives the three-dimensional object information regarding the target three-dimensional object from the second environment detection unit 42 and receives the driver's field of vision Lv from the field of vision estimation unit 51. If the control determination unit 52 then receives a signal from the second environment detection unit 42 indicating that no three-dimensional object information regarding the target three-dimensional object is available, or if the control determination unit 52 determines that the distance Lf from the vehicle 1 to the target three-dimensional object is equal to or less than the field of vision Lv, the collision prevention control is not executed and the determination result is output to the first collision prevention control unit 54 and the second collision prevention control unit 55.In other words, if no target three-dimensional object is located in front of the vehicle 1, it is not necessary to execute the collision avoidance control. If the distance Lf from the vehicle 1 to the target three-dimensional object is determined to be equal to or less than the field of view Lv, it is highly likely that the driver has already detected the target obstacle, and the collision avoidance control according to the present embodiment is not executed. The control determination unit 52 thus has the function of the determination device according to the present invention.

[0020] The oncoming vehicle detection unit 53 receives the vehicle speed V0 from the vehicle speed sensor 6 and receives the three-dimensional object information regarding the target three-dimensional object from the second environment detection unit 42. The vehicle speed V0 and the speed Vf of the target three-dimensional object are then compared to determine whether the target three-dimensional object is an oncoming vehicle or not, and the determination result is output to the first collision prevention control unit 54 and the second collision prevention control unit 55.In this embodiment, a determination is made as to whether the target three-dimensional object is an oncoming vehicle based on the vehicle speed V0, received by the vehicle speed sensor 6, and the speed Vf of the target three-dimensional object, received by the second environment detection unit 42. Alternatively, a determination as to whether the target three-dimensional object is an oncoming vehicle or not can be made based on, for example, vehicle-to-vehicle communication, if the vehicles have a vehicle-to-vehicle communication system.

[0021] The first collision prevention control unit 54 receives lane line information regarding the lane being traveled from the first environment detection unit 32, receives three-dimensional object information regarding the target three-dimensional object from the second environment detection unit 42, receives the vehicle speed V0 from the vehicle speed sensor 6, receives the steering angle θH from the steering angle sensor 7, and receives the road surface µ from the road surface µ estimator 8. Additionally, the first collision prevention control unit 54 receives a determination result indicating whether or not collision prevention control should be executed from the control determination unit 52 and receives a determination result indicating whether or not the target three-dimensional object is an oncoming vehicle from the oncoming vehicle determination unit 53.The first collision prevention control described later is then executed according to the flowchart as shown in . Fig. Figure 4 shows that if the target three-dimensional object is located in the lane of vehicle 1, a notification is given when the target three-dimensional object approaches a distance smaller than a predetermined limit Lal1. More precisely, a signal is sent to the warning control unit 56, for example, to activate a warning lamp 9, thus informing the driver of the possibility of a collision. If it is determined that braking cannot be performed within a timeframe after the target three-dimensional object enters the driver's field of vision, a signal is sent to the brake control unit 57 to activate the brake drive unit 10, thus initiating automatic braking.

[0022] The second collision prevention control unit 55 receives lane line information from the lane from the first environment detection unit 32, receives three-dimensional object information regarding the target three-dimensional object from the second environment detection unit 42, receives the vehicle speed V0 from the vehicle speed sensor 6, receives the steering angle θH from the steering angle sensor 7, and receives the road surface µ from the road surface µ estimator 8. Additionally, the second collision prevention control unit 55 receives a determination result indicating whether or not collision prevention control should be executed from the control determination unit 52 and receives a determination result indicating whether or not the target three-dimensional object is an oncoming vehicle from the oncoming vehicle determination unit 53.Subsequently, the second collision prevention control described later is executed according to the flowchart as shown in . Fig. Figure 5 illustrates this. In the case that the target three-dimensional object is an oncoming vehicle, a notification is issued when the target three-dimensional object (oncoming vehicle) approaches a distance smaller than the predetermined limit Lal2. More precisely, a signal is sent to the warning control unit 56, for example, to activate a warning lamp 9, thus informing the driver of the possibility of a collision. If vehicle 1 enters the lane of the oncoming vehicle and it is determined that braking cannot be performed within a time corresponding to the distance between vehicle 1 and the oncoming vehicle, a signal is sent to the brake control unit 57 to activate the brake drive unit 10, thus initiating automatic braking.As previously described, the first collision prevention control unit 54 and the second collision prevention control unit 55 are provided to have the functions of a collision possibility determination device and a collision prevention control device according to the present invention.

[0023] The following describes the vehicle driving assistance control, which is executed by control unit 5, configured as described above, with reference to the flowcharts according to the Fig. 3, Fig. 4 to Fig. 5.

[0024] Fig. Figure 3 shows the complete program of the vehicle assistance control system. In step 101 (hereinafter abbreviated as "S"), necessary information is read. This necessary information includes the lane line information for the lane being traveled, the three-dimensional object information for the target three-dimensional object, the vehicle speed V0, the steering angle θH, and the road surface µ.

[0025] The program then proceeds to S102, where the control determination unit 52 determines whether three-dimensional object information is available in front of the vehicle. If no target three-dimensional object information is available in front of the vehicle, it is not necessary to perform the collision prevention control, and the program therefore terminates without further process steps. If three-dimensional object information is available in front of the vehicle, the program proceeds to S103.

[0026] As previously described, in S103 the driver's field of view Lv is determined as follows: for example, a human average visual contrast value for detecting the lane markings on the road surface is pre-set as a limit value through testing. The field of view estimation unit 51 compares the lane marking information regarding the lane being driven on, received from the first environment detection unit 32 (distance information of the lane markings ahead), and the limit value and the furthest distance of the lane markings detected with a contrast value higher than this limit value are determined as the driver's field of view Lv.

[0027] In the following step S104, the control determination unit 52 compares the distance Lf to the target three-dimensional object and the field of view Lv. If the distance Lf to the target three-dimensional object is determined to be equal to or less than the field of view Lv, it is highly likely that the driver has already perceived the target object or obstacle. Accordingly, it is determined that the collision prevention control according to this embodiment does not need to be executed, and the program exits without further process steps. If the distance Lf to the target three-dimensional object is greater than the field of view Lv, the process is carried out as follows. If a target three-dimensional object is within the driver's field of view and it is highly likely that the driver has not perceived the target obstacle, the program proceeds to S105.More precisely, when collision avoidance control is activated for a target obstacle that the driver has already identified, warnings and controls are being implemented for a hazard that the driver is already well aware of and therefore unnecessary. This can lead to the driver becoming accustomed to such warnings and controls. As a result, a delay in the driver's reaction may occur when the hazard is actually imminent, or the driver may feel that the warning or control is intrusive and disable the driver assistance system altogether, thus preventing the original function of the driver assistance control device from being performed.The driving assistance control device 2 according to this embodiment is therefore configured to perform the collision prevention control for a target three-dimensional object which the driver is presumed not to have recognized yet, as it is located outside the driver's field of vision.

[0028] In step S105, the oncoming vehicle detection unit 53 determines, as previously described, whether an oncoming vehicle is present. If the target three-dimensional object is not an oncoming vehicle, the program proceeds to S106 to perform the first collision avoidance control, and then the program exits. If the target three-dimensional object is an oncoming vehicle, the program proceeds to S107 to perform the second collision avoidance control, and then the program exits.

[0029] Step S106, in which the first collision prevention control is performed by the first collision prevention control unit 54, is described with reference to the Fig. 4 and Fig. 6 described.

[0030] First, step S201 determines whether the target three-dimensional object, identified by the first environmental detection unit 32 as previously described, is located in the vehicle's lane. If the target three-dimensional object is not in the vehicle's lane, which is estimated as a result of the determination in step S201, it is not necessary to execute the collision prevention control, and the program therefore terminates without further processing. If the target three-dimensional object is in the vehicle's lane, which is estimated as a result of the determination in step S201, the program proceeds to step S202, where the distance Lf from the vehicle 1 to the target three-dimensional object and the predetermined limit value Lal1 are compared.The predetermined limit value Lal1, for example, is a distance value obtained by multiplying the vehicle speed V0 and a certain predetermined intermediate vehicle time THWc, which is set (Lal1 = VO · THWc).

[0031] Then, if the distance Lf from vehicle 1 to the target three-dimensional object is equal to or greater than the predetermined limit Lal1 (Lf ≥ Lal1) as a result of the comparison in step S202, it is determined that a warning to the driver does not need to be issued, and the program exits without further processing steps. If the distance Lf from vehicle 1 to the target three-dimensional object is less than the predetermined limit Lal1 (Lf < Lal1), the program proceeds to step S203, where a signal is issued to the warning control unit 56, for example, to activate a warning light 9, thus informing the driver of the possibility of a collision.

[0032] Subsequently (after step S203), the program proceeds to step S204, where the field of view Lv and the predetermined brake activation distance Lc1 are compared in advance, i.e., forward. In this case, the brake activation distance Lc1 is, for example, a distance calculated by equation (1) as follows: Lc1=VOF2 / (2⋅Δa0) where Δa0 denotes a relative deceleration rate that can be controlled by vehicle 1, and is a difference between the deceleration rate of the target three-dimensional object and the maximum deceleration rate of vehicle 1, which is set by calculation (or by querying a map or the like) in accordance with the road surface µ. If the field of view Lv is equal to or greater than the predetermined brake activation distance Lc1 (Lv ≥ Lc1), the driver can handle the target three-dimensional object himself when the target three-dimensional object enters the field of view Lc1, and therefore the program is exited without further processing steps.If the field of view Lv is smaller than the predetermined brake activation distance Lc1 (Lv < Lc1), it is determined that the brake operation cannot be performed in a time after the target three-dimensional object enters the driver's field of view, and therefore the program proceeds to step S205.

[0033] In step S205, as in Fig. Figure 6 shows the lane of vehicle 1 estimated on the basis of the vehicle speed V0 and the steering angle θH, for example by approximation using the path of a curve radius ρa according to the following equation (2): ρa=(1+A⋅V02)⋅|⋅n / θHe where A denotes a steering characteristic, I denotes a wheelbase, n denotes a steering gear ratio, and θHe denotes a steering angle prediction value. In Fig. 6 is the target three-dimensional object labeled S1. The steering angle prediction value θHe is calculated by the following equation (3): θHe=θH+(dθH / dt)⋅Δt where (dθH / dt) denotes a steering angular velocity and Δt denotes a predetermined time.

[0034] The program then proceeds to step S206, where, based on the curve radius ρa of the lane of vehicle 1, determined in step S205, the position in the latitude direction Wa of vehicle 1 at the distance Lf from vehicle 1 to the target three-dimensional object is determined, for example by the following equation (4): Wa=ρa−ρa⋅sin(cos−1(Lf / ρa))

[0035] The program then proceeds to step S207, where the lateral direction position Wa of vehicle 1 at distance Lf from vehicle 1 to the target three-dimensional object is compared with the lateral direction position Wf at the end of the target three-dimensional object. If Wa is greater than Wf (Wa > Wf), it is determined that the driver is performing a collision avoidance action and the program exits without further processing.

[0036] If Wa is equal to or less than Wf (Wa ≤ Wf), it is determined that the driver is not performing a collision avoidance action, and the program proceeds to step S208, where a signal is sent to the brake control unit 57 to activate the brake drive unit 10, thus initiating automatic braking. The program then exits.

[0037] As previously described, according to the first collision prevention control system of the present embodiment, if the target three-dimensional object is a three-dimensional object in the lane of the vehicle 1, a notification is issued as follows: if the target three-dimensional object approaches a distance that is less than the predetermined limit Lal1, a signal is issued to the warning control unit 56 to, for example, switch on a warning lamp 9, thus informing the driver of the possibility of a collision. If it is determined that the braking operation cannot be performed in time after the target three-dimensional object enters the driver's field of vision, a signal is issued to the brake control unit 57 to activate the brake drive unit 10 so that automatic braking is performed.As a result, with regard to a target three-dimensional object, which the driver is assumed not to actually be able to recognize, collision prevention control such as notification (warning) and brake activation can be carried out appropriately for the driver.

[0038] Step S107 of the flowchart of the vehicle driving assistance control program according to Fig. 3, that is, the second collision prevention control performed by the second collision prevention control unit 55, is described below with reference to the Fig. 5 and Fig. 7 described.

[0039] First, in step S301, the distance Lf of vehicle 1 to the target three-dimensional object and the predetermined limit Lal2 are compared. In this case, the predetermined limit Lal2 is, for example, a distance value obtained by multiplying the vehicle speed V0 and a specific predetermined time Tc (Lal2 = V0 · Tc).

[0040] Then, if the distance Lf from vehicle 1 to the target three-dimensional object is equal to or greater than the predetermined limit Lal2 (Lf ≥ Lal2) as a result of the comparison in step S301, it is determined that no warning needs to be issued to the driver, and the program exits without further processing steps. If the distance Lf from vehicle 1 to the target three-dimensional object is less than the predetermined limit Lal2 (Lf < Lal2), the program proceeds to step S302, where a signal is issued to the warning control unit 56, for example, to activate the warning lamp 9, thus informing the driver of the possibility of a collision with the oncoming vehicle.

[0041] The program then proceeds to step S303, where, as in Fig. Figure 7 shows that the lane of vehicle 1 is estimated on the basis of the vehicle speed V0 and the steering angle θH, for example by approximation using the path taken with a curve radius ρa according to equation (2) above. Fig. Vehicle 7 is the oncoming vehicle, designated S2.

[0042] The program then proceeds to step S304, where, based on the curve radius ρa of the lane estimated in step S303 and the width-direction distance W1 of vehicle 1 to the lane of the oncoming vehicle, the distance Ld of vehicle 1 to a point where vehicle 1 enters the lane of the oncoming vehicle is calculated, for example by the following equation (5): Ld=ρa⋅cos(sin−1(ρa−WI) / ρa)

[0043] The program then proceeds to step S305, where the distance Lf from vehicle 1 to the target three-dimensional object and the distance Ld of vehicle 1 to a point where vehicle 1 enters the lane of the oncoming vehicle are compared, and a determination is made as to whether Ld < Lf, that is, whether vehicle 1 enters the lane of the oncoming vehicle at a point in front of the oncoming vehicle.

[0044] If the result of the determination in step S305 is Ld ≥ Lf, the oncoming vehicle has already passed the point where vehicle 1 enters the oncoming vehicle's lane, and it is assumed that a collision between vehicle 1 and the oncoming vehicle can be avoided. Accordingly, the program terminates without further processing steps.

[0045] If Ld < Lf, vehicle 1 enters the lane of the oncoming vehicle at a point in front of it, and vehicle 1 can collide with it. Therefore, the program continues to step S306.

[0046] In step S306, the distance Lf from vehicle 1 to the target three-dimensional object (= Ld + Lc, where Lc is the distance from the point where vehicle 1 enters the lane of the oncoming vehicle to the oncoming vehicle) and the predetermined brake activation distance Lc2 are compared. In this case, Lc2 is derived, for example, by the following equation (6): Lc2=Ld+V0F2 / (2⋅Δac) where Δac is the maximum deceleration speed of vehicle 1 and is set by calculation (or by calling up a map or the like) in accordance with the road surface µ.

[0047] If the distance Lf from vehicle 1 to the target three-dimensional object (= Ld + Lc) is equal to or greater than the predetermined brake activation distance Lc2 (Lf ≥ Lc2) as a result of the determination in step S306, it is determined that vehicle 1 and the oncoming vehicle will not collide and the program exits without further process steps. If the distance Lf from vehicle 1 to the target three-dimensional object (= Ld + Lc) is less than the predetermined brake activation distance Lc2 (Lf < Lc2), it is determined that vehicle 1 will most likely collide with the oncoming vehicle, which is traveling in the oncoming vehicle's lane and is outside the field of view, and the program proceeds to step S307, where a signal is output to the brake control unit 57 to activate the brake drive unit 10 so that automatic braking is performed.The program will then be exited.

[0048] As previously described, according to the second collision prevention control of this embodiment, if the target three-dimensional object is an oncoming vehicle, a notification is issued as follows: If the distance between the target three-dimensional object (oncoming vehicle) and the vehicle 1 is less than the predetermined limit Lal2, a signal is issued to the warning control unit 56 to, for example, switch on the warning lamp 9, so that the driver is informed of the possibility of a collision.If it is determined that the braking operation cannot be executed in time due to the distance between vehicle 1 and the oncoming vehicle when vehicle 1 enters the lane of the oncoming vehicle, a signal is sent to the brake control unit 57 to activate the brake drive unit 10, thus initiating automatic braking. As a result, collision avoidance measures, such as a notification (warning) and brake activation, can be implemented appropriately for the driver with regard to the oncoming vehicle, which the driver is presumed to be unable to properly detect.

[0049] In the described embodiment of the present invention, lane line detection and field of view adjustment are performed based on image information provided by the stereo camera unit 3. Alternatively, lane line detection and field of view adjustment can be performed based on image information provided by a single-lens camera unit or a color camera unit. In the present embodiment, the second environmental sensing unit is configured to detect three-dimensional object information using radio wave information provided by a millimeter-wave radar. Alternatively, three-dimensional object information can be detected using optical wave information provided by a laser radar. SUMMARY OF THE REVELATION

[0050] A vehicle assistance control device is provided. A control unit 5, mounted on a vehicle 1, receives lane line information from a stereo camera unit 3 and three-dimensional object information about a target three-dimensional object from a millimeter-wave radar unit 4. Based on the lane line information, it estimates the driver's field of vision, determines whether the target three-dimensional object is outside the driver's field of vision, and determines the possibility of a collision between the target three-dimensional object and the vehicle 1. If the target three-dimensional object is outside the driver's field of vision, the control unit 5 performs at least one action, from notifying (warning) the driver to applying automatic braking, depending on the possibility of a collision with the vehicle 1.

Claims

[1] Vehicle driving assistance control device (2), comprising: a first environment detection device (3) for detecting lane line information relating to a preceding lane, based on image information, a second environment sensing device (4) for detecting ahead three-dimensional object information, based on transmitted and received radio wave information, a vision range estimation device (51) for estimating the vision range (Lv) of a driver based on lane line information, wherein a vision range estimation unit (51) previously sets a human average visual contrast value for detecting a lane line as a limit value and, as the driver's vision range (Lv), estimates a distance to a detected lane line with a contrast value higher than the limit value, a determining device (52) for determining whether the detected three-dimensional object is outside the driver's field of vision (Lv), a collision possibility determination device (54; 55) for determining the possibility of a collision between the detected three-dimensional object and the vehicle (1), and a collision prevention control device (54; 55) for performing at least one action based on a notification to the driver and an application of automatic braking according to the possibility of a collision of the detected three-dimensional object with the vehicle (1) when the detected three-dimensional object is outside the driver's field of vision (Lv). [2] Vehicle driving assistance control device (2) according to claim 1, wherein, when the distance between the three-dimensional object and the vehicle (1) becomes smaller than a predetermined limit value (Lal1; Lal2), a collision prevention control unit (54; 55) notifies the driver of the possibility of collision. [3] Vehicle driving assistance control device (2) according to claim 2, wherein in the case that the three-dimensional object is a three-dimensional object in a lane of the vehicle (1), the collision prevention control unit (54; 55) performs automatic braking when it is determined that the braking operation cannot be performed in time after the target three-dimensional object comes into the driver's field of vision (Lv). [4] Vehicle driving assistance control device (2) according to claim 3, wherein the collision prevention control device (54; 55) estimates the driving path of the vehicle (1) and the execution of automatic braking is prevented if the estimated driving path for avoiding the three-dimensional object lies on the driving path of the vehicle (1). [5] Vehicle driving assistance control device (2) according to one of claims 1 to 4, wherein, when the three-dimensional object is an oncoming vehicle and the vehicle (1) enters a lane of the oncoming vehicle in which the oncoming vehicle is driving, the collision prevention control unit (54; 55) performs automatic braking according to the distance from the vehicle (1) to the oncoming vehicle.

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