JP5609293B2 - Lane departure warning device and warning method - Google Patents

Description

  The present invention relates to a lane departure warning device and a warning method capable of suppressing an unnecessary lane departure warning when warning a departure from a travel lane of a vehicle.

Conventionally, various technologies have been developed to warn the driver of a departure when the vehicle deviates from the lane in which the vehicle is traveling. Further, in such a lane departure warning technology, a warning that is considered unnecessary for the driver is suppressed. Technology has been developed.
For example, in Patent Document 1, when a lane departure alarm is frequently generated in a specific road section, it is determined as a false alarm, the road section where the false alarm is generated is stored and stored, and an alarm is issued while traveling on the road section. A technique for changing to a condition that does not easily occur (specifically, no alarm is performed) is described.

JP 2002-92794 A

However, according to the technique described in Patent Document 1, there is a problem that there is a lack of immediacy because the road section is stored and the condition is changed, and there is a problem that real-time correspondence is difficult.
The present invention has been devised in view of such a problem, and an object thereof is to provide a lane departure warning device and a warning method capable of suppressing an unnecessary lane departure warning with good immediacy. And

  In order to achieve the above object, a lane departure warning device according to the present invention is a lane departure warning device that warns of a departure from the traveling lane of the host vehicle, wherein the position of the white line that defines the traveling lane is set to the position of the host vehicle. A white line recognizing means for recognizing the above, a deviation determining threshold setting means for setting a deviation determining threshold for the position of the white line, and the deviation determining threshold set by the deviation determining threshold setting means and the white line recognizing means Deviation determination means for comparing the position of the own vehicle to determine deviation of the own vehicle, and alarm means for warning the deviation when the deviation determination means determines that there is a deviation of the own vehicle, The departure determination threshold value setting means changes the current departure determination threshold value to the outside of the lane by a predetermined value from the previous departure determination threshold value when a predetermined number of warnings occur within a predetermined time. It is characterized in Rukoto.

The departure determination threshold setting means changes the current departure determination threshold to the inside of the lane by a predetermined value from the previous departure determination threshold if no alarm occurs even after the predetermined time has elapsed. It is preferable to do.
Further, it is preferable that a change permission range in which the deviation determination threshold setting unit permits the change of the departure determination threshold is set in advance. Further, it is preferable that the departure determination threshold setting means changes the departure determination threshold independently on the left and right sides of the host vehicle independently.

Further, the lane departure warning method of the present invention is a lane departure warning method for warning a departure from the traveling lane of the host vehicle in a lane departure warning device comprising an imaging means, a warning means and a control means , wherein the control means Is a white line recognition process for recognizing the position of a white line defining the travel lane with respect to the position of the host vehicle by performing image processing on the image acquired by the imaging means, and a deviation for setting a deviation determination threshold for the position of the white line A determination threshold value setting step, a deviation determination step for determining a deviation of the own vehicle by comparing the deviation determination threshold value set in the deviation determination threshold value setting step and the position of the own vehicle recognized in the white line recognition step; It performs an alarm process that deviations the alarm means to alert when it is determined the Yes departure of the vehicle and in the deviation determining step, in the deviation determination threshold setting step, previously set at a predetermined time When a predetermined number of times or more alarm that occurs, is characterized by changing the current of the departure determination threshold from a previous said deviation determination threshold lane outward by a predetermined value.

In the departure determination threshold setting step, when the warning by the warning means does not occur even once after the predetermined time has passed, the current departure determination threshold is set to a predetermined lane from the previous departure determination threshold. It is preferable to change inward.

  According to the lane departure warning device and the warning method of the present invention, the departure determination threshold is set according to the state of occurrence of the warning, so that unnecessary lane departure warning can be suppressed with good immediacy.

1 is a block diagram showing an overall configuration of a lane departure warning device according to an embodiment of the present invention. It is a flowchart which shows the warning method by the lane departure warning apparatus which concerns on one Embodiment of this invention. It is a table | surface which shows the fuzzy rule which the attention determination means of the lane departure warning apparatus which concerns on one Embodiment of this invention uses. It is a typical top view of the road which shows the departure determination threshold value which the departure determination threshold value setting means of the lane departure warning apparatus concerning one Embodiment of this invention sets. (A), (b) is the typical top view of the road which shows the modification of the judgment reference value of the departure judgment threshold value which the departure judgment threshold value setting means of the lane departure warning device which concerns on one Embodiment of this invention sets. is there.

Hereinafter, embodiments of a lane departure warning device and a warning method thereof according to the present invention will be described with reference to the drawings.
[One Embodiment]
<Configuration>
As shown in FIG. 1, a lane departure warning device 1 according to an embodiment of the present invention includes a camera (imaging means) 2, a steering angle sensor 3, a winker sensor 4, an auxiliary brake sensor 5, a clutch sensor (shift). An operation sensor) 6, a vehicle speed sensor 7, an alarm unit 8, and an ECU (control unit) 10 are provided.

The camera 2 is an imaging unit that acquires an image of the road surface ahead of the traveling direction of the host vehicle, and the road image acquired by the camera 2 is input to the ECU 10.
The steering angle sensor 3 is a detecting means for detecting the steering angle of the steering wheel, the winker sensor 4 is a detecting means for detecting the operating state of the winker lever, and the auxiliary brake sensor 5 is an auxiliary brake such as an exhaust brake or a retarder. The clutch sensor 6 is a detection means for detecting the stepping operation state of the clutch as a shift operation, and the vehicle speed sensor 7 is a detection means for detecting the traveling speed of the host vehicle. .

Information acquired by the various sensors 3 to 7 is input to the ECU 10. A shift lever sensor may be provided instead of the clutch sensor 6 to detect the operation state of the transmission shift lever.
The warning means 8 issues a warning when the deviation determination means 15 described later determines that there is a vehicle departure, and operates based on a control signal from the ECU 10. Specifically, the alarm means 8 includes, for example, an alarm (vibration means), an alarm lamp (blink means), a display (display means), an actuator (vibration means) that vibrates a portion that contacts a driver such as a steering wheel or a seat. ) And the like.

  The ECU 10 is an electronic control unit including a memory, a CPU, and the like. The white line recognition unit 11, the attention determination unit 12, the lane change determination unit 13, the departure determination threshold setting unit 14, and the departure determination unit 15 are software. (Left departure warning timer 16L, right departure warning timer 16R, left departure warning counter 17L, and right departure warning counter 17R).

The ECU 10 has a camera 2 and various sensors 3 to 7 connected to its input side, and an alarm means 8 connected to its output side, and is based on information input from the camera 2 and various sensors 3 to 7. The alarm means 8 is controlled by performing various processes such as recognition, determination, and setting.
The white line recognition means 11 performs image processing on the road surface image input from the camera 2 and individually recognizes the white line defining the travel lane (travel lane) in which the host vehicle is traveling on the left and right sides of the host vehicle. The positions of the white lines on the left and right sides with respect to the position of the host vehicle (in other words, the position of the host vehicle with respect to the traveling lane defined by the white line) are recognized. As a method for recognizing a white line, for example, a known method such as binarizing and scanning an image and viewing a luminance distribution can be used.

The attention determining means 12 is a means for determining the attention level of the driver who is driving. In addition, about attention determination, since the well-known thing explained in full detail in the patent 3039327 can be utilized, detailed description is abbreviate | omitted.
Briefly, the attention determining means 12 is based on “monotonicity” reflecting the frequency of turn signals, auxiliary brakes, and shift operations, “steering amount” that is an integrated value of corrected steering per unit time, and white line recognition. Attentiveness is determined by fuzzy inference using three items of “meander rate” to calculate and calculate the vehicle wobble. The turn signal operation information is obtained from the turn signal sensor 4, the auxiliary brake operation information is obtained from the auxiliary brake sensor 5, and the shift operation information is obtained from the clutch sensor 6.

  The monotonicity is an item set to quantify including both the passage of time and the monotonous feeling. In order to reflect the passage of time, the monotonicity is calculated in such a manner that the monotonicity gradually increases if no operation is performed. Moreover, in order to quantify the monotonous feeling, the frequency of turn signals, auxiliary brakes and shift operations is reflected. This is based on the knowledge of the present inventor that the frequency of the operation system corresponds to a monotonous road environment and traffic situation.

  The steering amount is a value obtained by integrating the absolute value of the amount of steering operation per unit time without distinguishing the left and right directions. According to the knowledge of the present inventor, the amount of steering is increased because the driver frequently performs fine correction steering normally, but when the attention is reduced, one correction steering is increased and the frequency is decreased, and the steering amount is decreased. As the attentiveness decreases further, the time when the correction steering is not performed at all appears, and the steering amount is further reduced. The steering amount is a measure that comprehensively shows such characteristics, and is calculated as an integrated value of corrected steering per unit time based on information on the steering angle acquired from the steering angle sensor 3.

  The meandering rate is a value for evaluating the traceability with respect to the white line, and is represented by the standard deviation per unit time of meandering data obtained by measuring the movement of the center point of the white line on both sides. When attention is maintained, the driver unconsciously tries to keep his vehicle in the driving lane, and judges the attention based on the inventor's knowledge that he rarely steps over the white line. It is adopted as one of the items to be performed.

The attention determining unit 12 defines a fuzzy rule as shown in FIG. 3 and determines the attention using membership functions corresponding to the calculated monotonicity, steering amount, and meandering rate. Here, the attention is obtained at levels from 1 to 5 in increments of 0.5. Level 1 is set to have the lowest attention and level 5 has the highest attention.
The lane change determination means 13 changes the lane based on the steering angle acquired from the steering angle sensor 3, the turn signal information acquired from the turn signal sensor 4, and the relative positional relationship between the white line recognized by the white line recognition means 11 and the host vehicle. It is determined whether or not it is in the middle. Specifically, any one of (1) the steering angle is equal to or greater than a predetermined angle set in advance, (2) the winker lever is operated, and (3) the white line and the host vehicle is established. When the relative positional relationship is closer than a predetermined value set in advance, it is determined that the lane change has been made in response to the driver's request.

As shown in FIG. 4, the departure determination threshold setting means 14 sets the departure determination thresholds Th _L and Th _R used for the lane departure determination by the departure determination means 15 independently on the left and right sides of the own vehicle. It is. FIG. 4 is a plan view schematically showing the white line on the road and the vehicle traveling in the traveling lane so that the deviation determination thresholds Th _L and Th _R can be easily grasped. It is not an exact representation.

That is, the departure determination threshold setting means 14 sets the left departure determination threshold Th _L for the white line on the left side of the vehicle, and sets the right departure determination threshold Th _R for the white line on the right side of the vehicle. Here, in the following description, the deviation determination threshold values Th _L and Th _R are also simply referred to as “deviation determination threshold value Th” when they are not distinguished from each other.
The deviation determination threshold setting means 14 sets the position of the center in the width direction of the white line recognized by the white line recognition means 11 as the reference value (determination reference value) Th ₀ of the deviation determination threshold Th. This determination reference value Th ₀ is used for the first departure determination. That is, the determination reference value Th ₀ is an initial value of the departure determination threshold value Th. Then, the departure determination threshold value setting unit 14 changes the current departure determination threshold value Th (n) from the previous departure determination threshold value Th (n−1) by performing the first condition change and the second condition change described below. It is supposed to change.

In the first condition change, the current departure determination threshold Th (n) is set at a position where the previous departure determination threshold Th (n-1) is shifted inward by a preset change value d (for example, 10 cm). The timing at which the departure determination threshold setting unit 14 performs the first condition change is when the departure determination unit 15 determines that a first condition described later is satisfied.
In the second condition change, the current departure determination threshold Th (n) is set at a position where the previous departure determination threshold Th (n-1) is shifted to the outside of the lane by a predetermined value d (for example, 10 cm). The timing at which the departure determination threshold setting unit 14 performs the second condition change is when the departure determination unit 15 determines that a second condition described later is satisfied.

The first condition change and the second condition change are performed independently for each of the left and right departure determination threshold values Th. That is, not only when the deviation determination threshold Th is changed at the same time on both the left and right sides, there are cases where only the left deviation determination threshold Th _{L is} changed, and there is a case where only the right deviation determination threshold Th _{R is} changed.
Further, a change permission range is set in advance for the deviation determination threshold Th. Here, the change permission range is a range in which the determination reference value Th ₀ is used as a boundary value on the lane inner side, and a value obtained by changing the determination reference value Th ₀ by a predetermined value D (for example, 30 cm) outside the lane is used as a boundary value on the lane outer side. And

Allowable change range: judgment reference value Th ₀ to judgment reference value Th ₀ + predetermined value D
That is, in the first condition change, the change of the deviation determination threshold Th to the inside of the lane from the determination reference value Th ₀ is prohibited, and in the second condition change, the position shifted by the predetermined value D from the determination reference value Th _0. Further, the change of the deviation determination threshold Th to the outside of the lane is prohibited.
Note that, as described above with parentheses, the change value d is 10 cm and the predetermined value D is 30 cm, for example, but the size of each value is not limited to this. However, the predetermined value D is preferably an integral multiple of the change value d (D = nd).

The departure determination unit 15 compares the position of the host vehicle recognized by the white line recognition unit 11 with the departure determination threshold Th set by the departure determination threshold setting unit 14, and the position of the host vehicle exceeds the departure determination threshold Th. It is determined that the vehicle has deviated from the lane.
The departure determination means 15 also increments the left elapsed time T _L of the left departure warning timer 16L at a predetermined timing of the calculation cycle as shown in step S20 of FIG. 2, and the right elapsed time T _R of the right departure warning timer 16R. Is incremented. Note that the left elapsed time T _L is the elapsed time since the last change of the left departure determination threshold Th _L , and the right elapsed time T _R is the elapsed time from the last change of the right departure determination threshold Th _R. is there.

Further, when the first condition is satisfied with respect to any one of the left and right departure determination threshold Th, the departure determination means 15 passes the elapsed time of the departure warning timers 16L and 16R on the side where the first condition is satisfied (one side or both sides). T _L, as well as zero-cleared by resetting the T _R, deviation warning counter 17L on the side where the first condition is satisfied (one or both sides), the alarm number N _L of 17R, and to reset the N _R so as to zero clear Yes. The left departure alarm counter 17L counts the left alarm count N _L , and the right departure alarm counter 17R counts the right alarm count N _R.

The first condition is that the elapsed times T _L and T _R are predetermined times for the left elapsed time T _L accumulated by the left departure alarm timer 16L and the right elapsed time T _R accumulated by the right departure alarm timer 16R, respectively. T ₀ (for example, 10 minutes) or more. Then, when the departure determination unit 15 determines that the first condition is satisfied in at least one of the left and right, the departure determination threshold setting unit 14 changes the first condition as described above on the side where the first condition is satisfied. To implement.

Further, when the second condition is satisfied with respect to any one of the left and right departure determination threshold Th, the departure determining means 15 is an elapsed time of the departure warning timers 16L and 16R on the side (one side or both sides) where the second condition is satisfied. T _L, T _R to reset with reset to zero, deviation warning counter 17L on the side where the second condition is satisfied (one or both sides), the alarm count 17R N _L, N _R the predetermined number N ₁ (e.g., once) Is set to.

The second condition is that the alarm counts N _L and N _R are predetermined times for the left alarm count N _L accumulated by the left departure alarm counter 17L and the right alarm count N _R accumulated by the right departure alarm counter 17R, respectively. N ₀ (for example, twice, or even once) or more. Then, when the departure determination means 15 determines that the second condition is satisfied in at least one of the left and right, the departure determination threshold setting means 14 changes the second condition as described above on the side where the second condition is satisfied. To implement.

Note that a switch for turning on and off the departure warning function by the lane departure warning device 1 may be provided at a position near the driver, such as an instrument panel, and may be operated by the driver.
The ECU 10 configured as described above performs control according to the flowchart shown in FIG. Initially, the determination reference value Th ₀ is set as the departure warning threshold value Th on each of the left and right sides.

First, in step S10 (position recognition step and attention determination step), the white line recognition unit 11 recognizes the position of the white line and the position of the host vehicle, and the attention determination unit 12 determines the attention. Thereafter, the process proceeds to step S20.
In step S20 (timer increment step), the deviation determination unit 15. increments the left elapsed time T _L of the left departure warning timer 16L, increments the right elapsed time T _R of the right departure warning timer 16R. Thereafter, the process proceeds to step S30.

Step S30 In (first condition establishment determining step), whether the first condition is satisfied by deviation determining means 15, i.e., the predetermined time for the left elapsed time T _L and the right elapsed time T _R, respectively T ₀ (for example, 10 minutes ) Is reached. If either one in the first condition of right and left long satisfied, that is, at least one of the left elapsed time T _L and right elapsed time T _R proceeds to step S40 if it has reached the predetermined time T _0. If both have the first condition is satisfied, that is, the process proceeds to step S60 if neither the left elapsed time T _L and the right elapsed time T _R has not reached the predetermined time T _0.

In step S40 (first deviation determination threshold changing step), the deviation determination threshold setting means 14 changes the first condition for the deviation determination threshold Th on the side where the first condition is established in step S30. That is, if the left elapsed time T _L has reached the predetermined time T ₀ , the left departure determination threshold Th _L is changed to the lane inner side by the change value d. If the right elapsed time T _R has reached the predetermined time T ₀ , the right departure determination threshold Th _R is changed to the lane inside by the change value d. However, at this time, the change is restricted by the setting of the change permission range. That is, if the previous deviation determination threshold Th (n−1) is already at the position of the determination reference value Th ₀ that is the boundary value inside the lane within the change permission range, the previous deviation determination threshold Th (n−1) is used as it is. This deviation determination threshold value Th (n) is used. Thereafter, the process proceeds to step S50.

In step S50 (timer counter reset step), the deviation alarm timer 16L and / or 16R of changing the deviation determination threshold Th side is reset the elapsed time T _L and / or T _R to zero at step S40, deviation The alarm counter 17L and / or 17R resets the alarm frequency N _L and / or N _R to zero. Thereafter, the process proceeds to step S60.
In step S60 (departure determination step), the departure determination means 15 determines the departure of the host vehicle from the traveling lane based on the departure determination thresholds Th _L and Th _R. If it is determined that there is a deviation, the process proceeds to step S70, and if not, the process returns to the beginning of the flow.

In step S70 (lane change determination step), the lane change determination means 13 determines whether the lane is being changed. If it is determined that the lane is being changed, the process returns to the beginning of the flow. If not, the process proceeds to step S80.
In step S80 (alarm prohibition step), the attention level determination means 12 determines whether or not the attention level is not less than a predetermined value (for example, level 4 or higher). If the attention is higher than the predetermined value, the process returns to the beginning of the flow, and if not, the process proceeds to step S90. That is, if the attention is higher than the predetermined value in step S80, the alarm is prohibited.

In step S90 (alarm process), the alarm means 8 issues an alarm. Thereafter, the process proceeds to step S100.
In step S100 (counter increment process), the number of alarms N _L and / or N _R of the departure alarm counter 17L and / or 17R that issued the alarm in step S90 is increased by one. Then, the process proceeds to step S110.

In step S110 (second condition satisfaction determination step), a predetermined number N ₀ (for example, 2) is determined for whether or not the second condition is satisfied by the departure determination means 15, that is, for each of the left alarm number N _L and the right alarm number N _R. It is determined whether or not the time has reached. If the second condition is established on either the left or right side, that is, if at least one of the left alarm number N _L and the right alarm number N _R has reached the predetermined number N ₀ , the process proceeds to step S120. In both cases, if the second condition is not satisfied, that is, if both the left alarm number N _L and the right alarm number N _R are less than the predetermined number N ₀ , the process returns to the beginning.

In step S120 (second deviation determination threshold changing step), the deviation determination threshold setting means 14 changes the second condition with respect to the deviation determination threshold Th on the side where the second condition is established in step S110 (the side that issued the alarm). To implement. That is, when the left alarm number N _L reaches the predetermined number N ₀ , the left departure determination threshold Th _L is changed to the outside of the lane by the change value d. When the right alarm number N _R reaches the predetermined number N ₀ , the right departure determination threshold Th _R is changed to the lane outside by the change value d. However, at this time, the change is restricted by the setting of the change permission range. That is, if the previous departure determination threshold Th (n−1) is already at the position of the determination reference value Th ₀ + predetermined value D that is the boundary value outside the lane of the change permission range, the previous departure determination threshold Th (n− 1) is used as the current deviation determination threshold Th (n). Thereafter, the process proceeds to step S130.

In step S130 (timer reset step and counter setting step), and is reset on the side to change the departure determination threshold Th in step S120, the deviation warning timer 16L and / or 16R elapsed time T _L and / or T _R to zero At the same time, the departure alarm counter 17L and / or 17R sets the alarm frequency N _L and / or N _R to a predetermined frequency N ₁ such as 1, for example.
The flow consisting of steps S10 to S130 is repeated at a predetermined cycle while the vehicle is traveling.

<Action and effect>
Since the lane departure warning device according to an embodiment of the present invention is configured as described above, the following operations and effects are achieved.
The departure determination threshold setting means 14 performs the first condition change on the side where the first condition is satisfied when the first condition is satisfied, and changes the previous departure determination threshold Th (n-1) by the change value d to the lane. Since the current deviation determination threshold Th (n) is set at a position shifted inward, the deviation determination condition can be made stricter and the alarm can be easily generated (the alarm timing is advanced) when the alarm is not output for a certain period of time. .

  Further, the departure determination threshold setting means 14 performs the second condition change on the side where the second condition is satisfied when the second condition is satisfied, and changes the previous departure determination threshold Th (n−1) to the change value d. Since the current departure determination threshold Th (n) is set at a position shifted to the outside of the lane only, the departure determination condition can be relaxed to make it difficult to generate an alarm (slower alarm timing) when the alarm occurs frequently. .

In addition, since the change permission range is set for the departure determination threshold Th, it is possible to prevent the departure determination threshold Th from being set outside the lane more than the actual white line, and an unnecessary alarm without impairing safety. Can be suppressed.
Further, the departure determination threshold value Th can be changed finely step by step, and the departure warning optimal for the driving characteristics of the driver can be implemented with good immediacy.

Since the departure determination threshold value Th is set in this way, the driver's acceptability of the main lane departure warning is improved, and the number of cases where the driver turns off the departure warning function with a switch is reduced. There is also an advantage that the degree of contribution is improved.
Further, since the left and right departure determination threshold values Th are independently set separately, for example, it is possible to cope with a case where the road shoulder on one side is wide and the driver deviates intentionally.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.

For example, in the above embodiment, the white line recognition unit 11 recognizes the white line by performing image processing on the image captured by the camera 2, but the method of recognizing the white line is not limited to this. For example, a lane marker laid on the road is used. It may be used to recognize the position of the white line or the own vehicle.
Even if the white line cannot be sufficiently extracted by image processing, the white line is estimated using a known method based on the position of the host vehicle and the surrounding road environment, and the estimated white line is recognized as an actual white line. Also good. At this time, it is preferable that the camera 2 captures images including other vehicles, sidewalks, guard rails, roadside trees, road shoulders, and the like in addition to the white lines so that the white line recognition means 11 recognizes them.

Further, the white line recognition unit 11 may not be configured as a component in the ECU 10. That is, the white line recognition means 11 may be provided as a camera 2 ECU separately from the ECU 10 and information recognized by the white line recognition means 11 may be input to the ECU 10.
In the above embodiment, the attention determining unit 12 determines the attention using fuzzy reasoning from the monotonicity, the steering amount, and the meandering rate. However, a specific method for determining the attention is limited to this. First, the attention may be determined by another known method. For example, the camera may further include a camera that captures the driver's face, and the number of blinks and the time (opening value of the eye) during a predetermined time may be used. Or may be determined using the line-of-sight direction. Further, instead of determining the attention level by the level, the attention level may be determined by another scale such as a percentage. Furthermore, the attention determination unit 12 itself may not be provided. That is, the step of determining the attention level from step S10 of the flowchart shown in FIG. 2 may be omitted, and the step S80 for determining whether the attention level is equal to or greater than a predetermined value may be omitted.

  In the above embodiment, the lane change determination means 13 determines whether or not the lane is being changed based on the steering angle, the blinker information, the white line, and the relative positional relationship between the host vehicle. The specific method is not limited to this, and the driver's intentional lane change may be determined by another known method. For example, it is simply detected by the winker sensor 4 that the winker lever is operated. For example, it may be determined that the lane change is valid.

In the above embodiment, the deviation determination threshold value setting unit 14 changes the deviation determination threshold value Th by the same change value d in both the first condition change and the second condition change. May be set to different values for the first condition change and the second condition change. That is, for example, the change value d ₁ of the first condition change is set to be larger than the change value d ₂ of the second condition change, and the deviation determination threshold Th is changed more greatly when going to the inside of the lane than when going to the outside of the lane. You may be made to do.

In the above embodiment, the change permission range of the deviation determination threshold Th is set to a position shifted from the determination reference value Th ₀ by a predetermined value D (for example, 30 cm) from the determination reference value Th ₀ with the determination reference value Th ₀ as a base point. The size of the change permission range is not limited to this. For example, a limit value inside the deviation determination threshold Th is set according to the vehicle type of the host vehicle, and the change to the inside of the lane by a predetermined value from the determination reference value Th ₀ is performed. May also be allowed. Further, it is not always necessary to provide a change permission range.

In the above embodiment, the determination reference value Th ₀ of the deviation determination threshold Th is the center position of the white line, but may be an arbitrary position with respect to another white line, for example, as shown in FIG. it the inner position of the white line may be used as the determination reference value Th _0, a position outside of the white line may be used as the determination reference value Th _0, as shown in Figure 5 (b).
Further, in the above-described embodiment, the departure determination unit 15 actually steps the virtual white line defined by the departure determination threshold Th when the position of the host vehicle actually exceeds the departure determination threshold Th. However, when a deviation is predicted, it may be determined that there is a deviation. That is, for example, when the vehicle speed V acquired from the vehicle speed sensor 7 or the steering angle acquired from the steering angle sensor 3 is used and the departure from the lane is predicted to exceed the departure determination threshold Th after a predetermined time, It may be determined that there is a vehicle departure.

1 Lane departure warning device 2 Camera (imaging means)
3 Steering angle sensor 4 Blinker sensor 5 Auxiliary brake sensor 6 Clutch sensor (shift operation sensor)
7 Vehicle speed sensor 8 Alarm means 10 ECU
11 White line recognition unit 12 Attention determination unit 13 Lane change determination unit 14 Deviation determination threshold setting unit 15 Deviation determination unit 16L Left departure alarm timer 16R Right departure alarm timer 17L Left departure alarm counter 17R Right departure alarm counter d Change value Th, Th _L , Th _R deviation judgment threshold Th ₀ judgment reference value

Claims (6)

A lane departure warning device that warns of a departure from the traveling lane of the own vehicle,
White line recognition means for recognizing the position of the white line defining the travel lane with respect to the position of the host vehicle;
Deviation determination threshold setting means for setting a deviation determination threshold for the position of the white line;
Deviation determination means for comparing the departure determination threshold set by the departure determination threshold setting means with the position of the own vehicle recognized by the white line recognition means, and for determining the departure of the own vehicle;
Alarm means for warning the departure when the departure determining means determines that there is a departure from the own vehicle;
The departure determination threshold value setting means changes the current departure determination threshold value to the outside of the lane by a predetermined value from the previous departure determination threshold value when a predetermined number of warnings occur within a predetermined time. A lane departure warning device. The departure determination threshold setting means changes the current departure determination threshold to the inside of the lane by a predetermined value from the previous departure determination threshold if no alarm occurs even after the predetermined time has elapsed. The lane departure warning device according to claim 1. The lane departure warning device according to claim 1 or 2, wherein the departure determination threshold setting means is preset with a change permission range for permitting the change of the departure determination threshold. The lane departure according to any one of claims 1 to 3, wherein the departure determination threshold setting means changes the departure determination threshold independently on the left and right sides of the host vehicle independently. Alarm device. In a lane departure warning device comprising an imaging means, a warning means, and a control means, a lane departure warning method for warning a departure from the traveling lane of the host vehicle,
The control means includes
A white line recognition step of recognizing the position of a white line defining the travel lane with respect to the position of the host vehicle by performing image processing on the image acquired by the imaging unit ;
A deviation determination threshold setting step for setting a deviation determination threshold for the position of the white line;
A departure determination step for comparing the departure determination threshold set in the departure determination threshold setting step with the position of the own vehicle recognized in the white line recognition step to determine a departure from the own vehicle;
The deviation when said determining that there is deviation of the vehicle in the deviation determining step performs a warning process said alarm means to alert,
In the departure determination threshold setting step, when a predetermined number of warnings are generated within a predetermined time, the current departure determination threshold is changed from the previous departure determination threshold to the outside of the lane by a predetermined value. A lane departure warning method. In the departure determination threshold value setting step, when the warning by the warning means does not occur even once after the predetermined time has elapsed, the current departure determination threshold value is set to the inside of the lane by a predetermined value from the previous departure determination threshold value. The lane departure warning method according to claim 5, wherein the lane departure warning method is changed.

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