JP4872897B2 - Lane maintenance support device - Google Patents

Description

  The present invention relates to a lane keeping support device that detects a tendency of a lane marking to deviate and warns a driver, and in particular, if a lane marking on either the left or right side of the host vehicle is not detected, lane keeping that suppresses unnecessary warnings is provided. The present invention relates to a support device.

There is known a lane keeping assist device that assists a driver to steer a vehicle so that the vehicle travels in the vehicle lane based on the image of the vehicle. However, there are cases where lane markings (hereinafter referred to as white lines) are displayed on only one of the left and right sides of a road, such as a branch point or a junction, and lane maintenance control may be difficult. For example, if the lane keeping support device becomes more likely to deviate from the white line, it sounds an alarm sound to alert the driver, but if one of the white lines cannot be recognized, the error in the estimated position of the white line increases and an unnecessary warning is generated. It becomes easy to let you. Therefore, a lane keeping support device has been proposed that relaxes the criterion for deviation prediction when only one of the left and right white lines can be recognized (see, for example, Patent Document 1). In Patent Document 1, in a lane keeping assist device that determines a lane departure tendency based on a displacement amount of a forward gazing point calculated based on a yaw angle of a vehicle, when only one of the left and right white lines can be recognized, the displacement amount includes a yaw angle. Describes a lane keeping assist device that reduces the effect of.
Japanese Patent No. 3922194

  However, as in the lane keeping assist device described in Patent Document 1, when the judgment criterion for departure prediction is relaxed, there is no white line on either the left or right side, but a white line is erroneously recognized outside the road that should maintain a straight line or on the outside. In such a case, the alarm sound may not be sounded (no alarm) even if the sound of the alarm sound is delayed or deviated.

  When only one of the left and right white lines can be recognized, the lane keeping assist device may generate a virtual line on the unrecognized white line and determine the departure tendency based on the virtual line. However, if a virtual line is generated, on a road with an increasing number of lanes, if the lane is changed from the original travel lane to the increased travel lane, the virtual line will be deviated. Sound is blown (unnecessary alarm).

  In view of the above problems, the present invention provides a lane keeping support device that appropriately determines a deviation on the unrecognizable side and prevents unnecessary warning output or non-alarming when only one of the left and right lane markings can be recognized. Objective.

In view of the above problems, the present invention provides a lane line recognition means for recognizing a lane line and a vehicle in a lane keeping assist device that detects a tendency to deviate from at least one of the left and right lane line of the host vehicle and warns an occupant. Vehicle operation detection means for detecting the steering of the vehicle, virtual line setting means for setting a virtual line of the lane marking line on the undetectable side of the left and right lane marking lines , and left and right by the vehicle operation detection means A virtual line correcting means for moving the virtual line in the steering direction when steering of the vehicle is detected to the undetectable side of the lane line, and to the undetectable side of the left and right lane line, When the vehicle steering is detected by the vehicle operation detection means, the detection of the deviation tendency is eased only on the side of the left and right lane markings that cannot be detected.

According to the present invention, even if one of the white lines cannot be recognized and an error in the estimated position of the white line increases, the determination of the deviation tendency on the unrecognizable side is eased, so that an unnecessary alarm can be suppressed.
According to the present invention, since a virtual line is set on the unrecognizable side and moved according to the steering, it is difficult to deviate from the virtual line even if the lane is changed by merging, etc. Unnecessary alarms can be suppressed.

  In one embodiment of the present invention, the virtual line correcting means moves the virtual line in the steering direction in accordance with the amount of movement in the vehicle width direction.

  According to the present invention, since the virtual line is gradually moved according to the amount of movement of the vehicle, the distance between the vehicle and the virtual line can be appropriately maintained.

  In one embodiment of the present invention, the virtual line correcting means provides an upper limit for the moving speed of the virtual line.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that a virtual line moves with a vehicle and the deviation tendency of a virtual line becomes difficult to detect, and can output a warning with respect to a sudden lane change.

  When only one of the left and right lane division lines can be recognized, it is possible to provide a lane keeping support device that appropriately determines the deviation on the unrecognizable side and prevents the output of unnecessary warnings and non-alarms.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  The lane keeping assist device 100 according to the present embodiment generates a virtual line on the unrecognizable side and corrects the virtual line based on the driver's vehicle operation when either the left or right lane line is not recognized. For example, it is possible to detect the vehicle operation of the lane change by the driver and gradually correct the imaginary line in the lane change direction, so that it is possible to prevent departure from the imaginary line and suppress unnecessary warnings. When the driver does not change the lane, the virtual line is not corrected. Therefore, when the driver deviates from the virtual line, an alarm sound can be sounded, and there is no possibility of no alarm.

  FIG. 1 shows a block diagram of a lane keeping assist device 100 of the present embodiment. The lane keeping assist device 100 is controlled by the control unit 14. The control unit 14 is connected to the camera 11, the white line recognition unit 12, the torque sensor 13, and the alarm device 15 through a CAN (Controller Area Network) or a dedicated line.

  The camera 11 is mounted on, for example, an indoor room mirror with the optical axis directed slightly downward toward the front of the vehicle, and captures an area extending in a predetermined angular range in front of the vehicle. The camera 11 uses a photoelectric conversion element such as a CMOS (Complementary Metal Oxide Semiconductor) or a CCD (Charge Coupled Device) to generate image data (digital data) of a predetermined luminance gradation (for example, 256 gradations), for example, about 30 times per second, Output to the white line recognition unit 12.

  The white line recognition unit 12 detects left and right lane markings that divide the travel lane from image data captured by the camera 11. The lane markings are indicated by road markings in various colors, such as white lines and yellow lines, with solid lines or broken lines. In addition, the so-called BotsDots may be a lane marking, but the lane marking of the present embodiment is not limited to a road marking but may be a reflective member having a function of segmenting a lane (hereinafter, a lane marking is simply a white line). Called).

  For example, the white line recognition unit 12 searches for an area having a luminance equal to or higher than a predetermined threshold value from the bottom of the frame upward based on the luminance of the image data, and detects an edge. Since the white line has edges that are high-frequency components at both ends, when the luminance value of the image data is differentiated in the horizontal direction (for example, the Sobel operator is applied to the luminance value), peaks are obtained at both ends of the white line. A pixel having a horizontal luminance gradient or difference of a predetermined value or more is an edge. By extracting multiple edges detected in the vertical direction and performing Hough transform, a straight line expression of the left and right white lines is obtained, and by expressing each straight line as a model expression, the vanishing point (intersection) of the two white lines on the left and right Can be calculated. The model formula includes information such as road curvature, yaw angle, width, offset amount (hereinafter referred to as white line information), and the height of the camera 11 from the road surface and the angle formed by the optical axis with respect to the road surface are known. By converting the model formula into the coordinate system of the camera 11, white line information can be obtained.

  The white line recognition unit 12 cannot accurately determine the white line information unless one of the left and right white lines is recognized. Therefore, as will be described later, when one of the left and right white lines is not recognized, a virtual line is set using a relatively stable width (with little change). That is, a virtual line is generated on the unrecognized side using the past width in which the left and right white lines are recognized together. If any of the left and right white lines is recognized after the virtual line is set, the virtual lines are set on the side that is not recognized based on the recognized white line. In the present embodiment, even when one of the left and right white lines is not recognized, the width detected in an acquirable range is referred to as white line information.

  The torque sensor 13 has a structure in which, for example, a multipolar magnet and a yoke are connected via a torsion bar along the rotation axis of the steering shaft, and the torsion bar is twisted due to the steering torque generated in the steering wheel. Detection is based on a relative change between the magnet and the yoke, and the relative change is converted into an electrical signal by the Hall IC to detect the steering torque. Since the torque sensor 13 detects the driver's steering intention, a steering angle sensor or a yaw rate sensor may be used.

  The alarm device 15 is a buzzer generator or an amplifier or speaker that outputs a voice message. For example, a device having an alarm sound or voice output function, such as a meter computer or a navigation system, can be requested to sound an alarm sound or output a voice message. To sound an alarm sound or the like is hereinafter simply referred to as an alarm output.

  A power steering computer capable of controlling a power steering actuator that rotationally drives the steering shaft may be connected to the control unit 14. In this case, the control unit 14 sets the target steering force according to the offset amount in the opposite direction to the offset (for example, right is positive, left) Is negative) and sent to the power steering computer. Since the power steering computer steers the steering shaft according to the target steering force, the lane keeping assist control is realized so that the host vehicle travels in the travel lane.

  FIG. 2 is an example of a functional block diagram of the lane keeping assist device 100, and FIG. 3A is a diagram illustrating virtual lines 23 to 26 set by the lane keeping assist device 100. The control unit 14 is a computer in which a CPU, a RAM, a ROM, an input / output interface and the like are connected by a bus, and the virtual line setting unit 44, the CPU executes a program, or by hardware such as an arithmetic circuit or an IC. A vehicle operation detection unit 42, a virtual line correction unit 41, a lane departure determination unit 43, and an alarm request unit 45 are realized.

  Vehicles 21 </ b> A to 21 </ b> E indicate time-series positions of the same vehicle (the vehicle 21 is referred to when the vehicles are not distinguished). While the vehicle 21 </ b> A is traveling on a one-lane road, the white line recognition unit 12 recognizes the left white line 27 and the right white line 22 and sends the white line information to the lane departure determination unit 43. The lane departure determination unit 43 may deviate from the left white line 27 or the right white line 22 within a predetermined time based on the yaw angle, vehicle speed, and offset amount of the vehicle 21A (hereinafter referred to as “departure tendency”). An alarm is requested to the alarm request unit 45. The alarm device 15 outputs an alarm in response to a request from the alarm request unit 45.

  The road in FIG. 3A has a section without a white line on the right side because the number of lanes increases ahead. When the vehicle 21B comes to the front of the section where the right white line 22 is not displayed on the road surface, the white line recognition unit 12 lost the white line on the right side, and the one-side white line lost information indicating that the white line on the right side has been lost is the virtual line setting unit 44. To send. Thereby, the lane departure determination part 43 transfers to the one-side recognition mode. The loss of the white line on one side is determined from the fact that the edge of one white line is not detected from the image data and the edge of the other white line is detected. The virtual line setting unit 44 sets the virtual line 23 on the side where the white line is not recognized based on the white line information obtained so far. The virtual line 23 is set with respect to the left white line 27 so that the width of the left white line 27 and the right white line 22 is obtained for the vehicle 21B. Therefore, the virtual line 23 is set at a position where the right white line 22 is extended as shown in the figure. When the virtual line 23 is set, the lane departure determination unit 43 determines the steering departure of the vehicle 21B with respect to the virtual line 23 and the left white line 27.

  The vehicle operation detection unit 42 monitors the output of the torque sensor 13 and detects that the steering torque by the driver exceeds a predetermined value. This predetermined value is a steering torque that can be determined that the driver is willing to change lanes. When the lane operation detection unit detects a steering torque of a predetermined value or more, the lane operation detection unit sends steering torque information including the magnitude of the steering torque, the detection time, and the like to the virtual line correction unit 41.

  Then, the virtual line correction unit 41 determines the correction amount of the virtual line 23 based on the steering torque information with reference to the recognized position of the left white line 27 and sends it to the virtual line setting unit 44. For example, when the virtual line correction unit 41 acquires the steering torque information in the vehicle 21C, the virtual line correction unit 41 detects the movement amount in the vehicle width direction of the vehicle 21C based on the steering torque information, and calculates the virtual calculated according to the movement amount. The correction amount of the line 23 is sent to the virtual line setting unit 44. The virtual line setting unit 44 updates the virtual line 23 according to the correction amount and sets the virtual line 24.

  Therefore, the white line on the right side as viewed from the vehicle 21C becomes the virtual line 24. After that, when the vehicle 21D continues to steer, the virtual line 25 is generated with respect to the vehicle 21D according to the correction amount corrected by the virtual line correction unit 41. The virtual line 26 is set for the vehicle 21E. That is, the virtual lines 23 to 26 are set so as to keep the distance in the vehicle width direction between the vehicle 21 </ b> A and the right white line 22. Thus, even when the virtual line 23 is set when only one of the left and right white lines is not detected by the white line recognizing unit 12, if the driver changes the lane, the virtual lines 23 to 26 are also detected in the vehicle. Since it moves according to the movement amount in the width direction, an unnecessary alarm can be suppressed.

  As described above, the lane keeping assist device 100 according to the present embodiment, when the steering of the vehicle is detected to the undetectable side of the left and right lane markings, the deviation detection determination only on the undetectable side of the left and right lane markings. To ease.

  In addition, it is preferable that the virtual line correction unit 41 sets an upper limit on the moving speed of the virtual line 23. For example, if the driver steers the steering wheel unconsciously (disease, drowsiness, looking aside, etc.) and the amount of movement in the vehicle width direction becomes abrupt, the vehicle 21 will deviate from the virtual line 23 etc. An alarm can be output to alert the driver.

  FIG. 3B is a diagram illustrating an example of vehicle control in the case where steering torque greater than a predetermined value by the driver is not detected. When the right white line 22 is no longer recognized, the virtual line setting unit 44 of the vehicle 21B sets the virtual line 23 in the same manner. In this case, even if the driver does not operate the vehicle and the vehicle 21F tends to deviate from the virtual line 23, the virtual line 23 is not updated because the steering torque of a predetermined value or more is not detected. Therefore, the lane departure determination unit 43 can determine that there is a departure tendency before reaching the vehicle 21 </ b> F, and can output an alarm from the alarm device 15.

  FIG. 4 is a flowchart illustrating a procedure in which the lane keeping assist device 100 sets the virtual lines 23 to 26 according to the movement amount of the vehicle 21 in the vehicle width direction. The flowchart of FIG. 4 is repeatedly executed at predetermined cycle times while the lane keeping assist device 100 recognizes a white line.

  The white line recognizing unit 12 recognizes the left and right white lines. If the left and right white lines can be recognized, the white line information is displayed in the lane departure determination unit 43. If only one white line is detected, the one side white line lost information is displayed as the virtual line setting unit. 44 (S10). If neither the left or right white line can be recognized, the procedure of FIG. 4 is not executed.

  The lane departure determining unit 43 determines whether both the left and right white lines have been recognized (S20). When both the left and right white lines can be recognized (Yes in S20), the lane departure determination unit 43 determines a departure tendency based on the white line information (S60). When one of the left and right white lines cannot be recognized (No in S20), the lane departure determination unit 43 shifts to the one-side recognition mode, and the virtual line setting unit 44 sets the virtual line 23 (S30).

  Next, the vehicle operation detection unit 42 determines whether or not a steering torque greater than the degree of changing the lane is detected on the virtual line 23 side (S40). When the steering torque of a predetermined value or more is not detected (No in S40), the virtual line 23 is maintained as it is and is set to a position where the right white line 22 is extended.

  When a steering torque equal to or greater than a predetermined value is detected (Yes in S40), the virtual line correction unit 41 calculates the correction amount of the virtual line 23 according to the movement amount in the vehicle width direction and sends it to the virtual line setting unit 44. . The virtual line setting unit 44 updates the virtual line 23 to the virtual line 24 according to the correction amount (S50). Accordingly, the distance in the vehicle width direction between the vehicle 21B and the virtual line 23 and the distance in the vehicle width direction between the vehicle 21C and the virtual line 24 are kept substantially constant.

  Even if the steering torque once exceeds the predetermined value, the steering torque may be lower than the predetermined value during the lane change. However, when the steering torque is lower than the predetermined value, the virtual line 24 is maintained for a certain time. Thereby, even if the steering torque temporarily decreases during the lane change, it is possible to prevent an alarm from being erroneously output.

  In FIG. 3 (a), the number of lanes is increased to two. However, there are cases where the number of lanes increases to three or more lanes. Therefore, when a steering torque of a predetermined value or more is detected, control by increasing the lane width is temporarily performed. Interrupt.

  Next, the lane departure determination unit 43 determines whether or not the vehicle 21C has a tendency to depart (S60). That is, the vehicle 21C with respect to the virtual lines 24 to 26 and the left white line 27 when a steering torque greater than a predetermined value is detected, and the virtual line 23 and the left white line 27 when no steering torque greater than a predetermined value is detected. It is determined whether or not there is a tendency to deviate.

  As a result of the determination, when there is a tendency to deviate (Yes in S60), the alarm request unit 45 requests the alarm device 15 to output an alarm (S70).

  The white line recognizing unit 12 has reached a level where the movement amount of the vehicle 21C in the vehicle width direction can be regarded as a lane change, or when the steering torque is stabilized at zero (a level that is determined to be directed straight). , Restart the recognition of the left and right white lines. Thereby, after the number of lanes increases and the lane change is completed, it is possible to make a departure determination based on the white line information in which the left and right white lines are recognized. The lane keeping assist device 100 repeats the above processing.

  In this embodiment, the lane change is detected based on the steering torque. However, based on the steering angle sensor or the yaw rate sensor (gyro sensor), the lane change of the vehicle 21 and the movement amount in the vehicle width direction are detected, and the virtual line 23 is displayed. It may be updated.

  Also, the fact that no white line is displayed on one side and the increase in the number of lanes are acquired by road map information, blinker switch, vehicle-to-vehicle communication or road-to-vehicle communication of the navigation system, and setting and updating of the virtual line 23 is started. May be. In this case, the moving speed of the virtual line 23 may be set according to the vehicle speed, for example, or may be set to a typical moving speed when the lane is changed.

  Also, in this embodiment, the increase in the number of lanes has been described as an example, but it can be suitably applied to road sections where one of the white lines is not displayed and the number of lanes changes, such as a decrease in the number of lanes, merge, branching, etc. .

  As described above, according to the present embodiment, since the position of the virtual line 23 is corrected in the one-side recognition mode, it is possible to suppress an unnecessary alarm due to deviation detection on the side where the white line is not recognized.

  In the one-side recognition mode, only the white line on one side is recognized, so the error in the position of the recognized left white line 27 may be large. FIG. 5 is a diagram illustrating an example of an unnecessary alarm that can occur in the one-side recognition mode. When the vehicle 21 shifts to the one-side recognition mode, the vehicle 21 sets the virtual line 23 by applying the white line information (for example, the width) so far to the recognizable left white line 27, but the error included in the position of the recognized white line 28 gradually increases. Become. Therefore, if the virtual line 23 is set apart from the recognized white line 28 by the width detected when both the left and right white lines are recognized, the error of the position of the virtual line 23 also increases with respect to the right white line 22. For this reason, even if the vehicle 21 is traveling substantially in the center of the travel lane, the vehicle 21 will eventually deviate from the virtual line 23 and an unnecessary warning will be output.

  Therefore, the lane keeping assist device 100 according to the present embodiment detects the driver's arousal level, and outputs a warning when the driver's arousal level is high and the vehicle 21 is traveling straight ahead. Is prohibited. Therefore, when the driver's arousal level is high even in the one-side recognition mode, the output of an unnecessary alarm can be suppressed.

  Fig.6 (a) shows an example of the block diagram of the lane maintenance assistance apparatus 100 of a present Example. In FIG. 6A, the same components as those in FIG. In FIG. 6A, a face camera 16 that captures the driver's face and a wakefulness detection unit 17 that detects the eye opening from the driver's face image are connected to the control unit 14.

  The face camera 16 has an optical axis in the direction in which the driver's face exists (backward and obliquely upward) through the fan-shaped opening surrounded by the periphery of the steering wheel and the spokes, for example, in the upper column of the steering column. Placed. It may be arranged on the meter panel. The face camera 16 is arranged on a vertical axis passing through the center of the steering wheel so as to photograph the driver's face image from the front.

  The face camera 16 has the same number of infrared projectors on the left and right sides. The infrared projector is an LED lamp that projects near-infrared light toward the driver's face, and enables photographing of the driver's face at night. The face camera 16 is composed of a CCD, a CMOS, or the like, and is sensitive to infrared light (a peak wavelength of about 870 nm) irradiated by an infrared projector. After converting incident light into electricity, digital data of a predetermined gradation is obtained. (Face image) is generated.

  The face camera 16 and the infrared projector are controlled by the arousal level detection unit 17. For example, the infrared projector emits light 60 times per second and irradiates near infrared light toward the driver's face. The driver's face image irradiated with light is acquired at 30 frames per second and sent to the arousal level detection unit 17.

  The arousal level detection unit 17 performs known eye open / close detection. Eye opening / closing detection will be briefly described. The arousal level detection unit 17 extracts edge information from the face image supplied from the face camera 16, and generates an edge image obtained by binarizing the face image by comparing the edge strength with a threshold value. Then, a histogram is created by projecting the edge points of the edge image vertically downward, and both ends of the face where the histogram shows a peak are detected.

  The arousal level detection unit 17 detects the center line of the face so that the number of edge points is equal to the left and right, and calculates the face orientation angle from the ratio of the left and right faces from the center line to both ends. The face-facing angle is 0 ° when the driver looks straight ahead in the vehicle traveling direction along the traveling lane during straight traveling, and the right direction is positive, for example.

  The arousal level detection unit 17 detects a nostril position that is relatively easy to detect from the face image, sets an eyeball tracking area from the nostril position using statistical information on the relative relationship between the nostril position and the eye position, and sets the eyeball tracking area. Are scanned from top to bottom and from bottom to top to detect the edges of the eyelids. The edge positions of the upper and lower eyelids indicate the size of the eye opening.

  The arousal level detection unit 17 determines the opening / closing of the eye by comparing the eye opening of the driver in the awake state acquired in advance with the detected eye opening. Then, the closed eye measurement time is counted each time the closed eye is detected, and the closed eye measurement time is reduced every time the opened eye is detected. Therefore, when the closed eye is continuously detected, the closed eye measurement time increases. The arousal level detection unit 17 requests the alarm device 15 to output an alarm, for example, assuming that the driver feels strong sleepiness when the closed eye measurement time exceeds a predetermined threshold.

  The lane keeping assist device 100 according to the present embodiment detects the driver's arousal level based on the closed eye measurement time, and the closed eye measurement time is based on the above threshold (or a suitable threshold for the lane keeping assist device 100). Determine whether the value is high or low.

  Note that the driver's arousal level may be determined based on biological information such as body temperature, pulse rate, respiratory rate, and skin potential, or may be detected because the movement of the face and wrinkles is small. .

  FIG. 6B is a diagram illustrating an example of a functional block diagram of the present embodiment. In FIG. 6B, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. The alarm prohibition unit 46 acquires the closed eye measurement time measured by the arousal level detection unit 17 and determines whether the driver's arousal level is low or high. Further, the steering prohibition information is sent from the vehicle operation detection unit 42 to the alarm prohibition unit 46. Since the steering direction of the vehicle 21 is detected based on the steering torque information, the alarm prohibiting unit 46 is when the recognized white line 28 or the virtual line 23 changes in a direction different from the steering direction and the arousal level is high. The alarm request unit 45 is prohibited from outputting an alarm.

The case where the recognized white line 28 or the virtual line 23 changes in a direction different from the steering direction is, for example, the following situation.
-When the recognized white line 28 or the imaginary line 23 changes to the right or left in a state where the steering torque is not detected (travels straight ahead).
When the recognized white line 28 or the virtual line 23 changes to the left while the steering torque is detected to the right. When the steering torque is detected in the right direction, the virtual line correcting unit 41 corrects the virtual line 23 in the right direction. However, when the error of the recognized white line 28 increases and changes to the left direction, the virtual line is separated into the recognized white line 28 with a width separated. Since the position of the line 23 also changes, it may be determined that there is a departure tendency of the virtual line 23 even if the virtual line correcting unit 41 corrects the virtual line 23 in the right direction. The left white line 27 may be straight or curved left and right.
When the recognized white line 28 or the virtual line 23 changes to the right while the steering torque is detected to the left. In this case, since the recognized white line 28 is the side on which the white line is marked, the virtual line correcting unit 41 does not correct the recognized white line 28 in the left direction. Therefore, when the error of the recognized white line 28 increases and changes to the right, a tendency to deviate from the recognized white line 28 may be detected. The left white line 27 may be straight or curved left and right.

  Even if the recognized white line 28 or the virtual line 23 changes in a direction different from the direction steered by the driver, if the driver's arousal level is high, the driver's steering can be trusted to suppress unnecessary warnings. it can.

  In addition, not only the arousal level but also a side-by-side detection may be detected, and control may be performed so as not to prohibit the output of the alarm when the side is looking aside even if the arousal level is high.

  FIG. 7 shows a case where the driver's arousal level is high, and the lane keeping assist device 100 prohibits the warning output when the recognized white line 28 or the virtual line 23 changes in a direction different from the direction in which the driver steers. It is a flowchart figure which shows a procedure. In FIG. 7, the same steps as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  The white line recognizing unit 12 recognizes the left and right white lines (S10). When both the left and right white lines can be recognized, the white line information is given to the lane departure judging unit 43, and when only one white line is recognized, the one side white line is lost. The information is output to the virtual line setting unit 44 (S20). When the white line information cannot be acquired, the lane departure determination unit 43 shifts to the one-side recognition mode, and the virtual line setting unit 44 sets the virtual line 23 (S30).

  Next, the warning prohibition unit 46 detects the arousal level based on, for example, the driver's closed eye measurement time (S110), and determines whether the arousal level is high (S120). When the arousal level is not high (Yes in S120), the alarm prohibition unit 46 does not prohibit the alarm by the alarm request unit 45 (S160).

  When the arousal level is high (Yes in S120), the vehicle operation detection unit 42 detects the steering torque (S130). The warning prohibition unit 46 determines whether or not the steering torque is greater than or equal to a predetermined value (S140), and if the steering torque greater than or equal to the predetermined value is not detected (Yes in S140), it is estimated that the driver is going straight in the awake state. Therefore, the alarm prohibition unit 46 prohibits the alarm by the alarm request unit 45 (S150). Therefore, even if the recognized white line 28 changes in a direction other than straight traveling, and the lane departure determination unit 43 determines that there is a tendency to deviate from the recognized white line 28 or the virtual line 23, the unnecessary alarm can be suppressed. Note that it is not determined whether a steering torque greater than a predetermined value is detected, but whether a steering angle greater than a predetermined value is detected, and whether a yaw rate greater than a predetermined value is detected. Good.

  Further, when a steering torque of a predetermined value or more is detected (No in S140), it may be estimated that the driver is steering the steering wheel in an awake state. Is not prohibited (S160). Therefore, for example, an alarm can be output when it is likely to deviate from the recognized white line 28 or to deviate from the virtual line 23 by steering.

  According to the present embodiment, only one of the left and right white lines is recognized, and the error of the recognized white line 28 becomes large. Even if there is a tendency to deviate in a direction different from the steering of the driver, an alarm is output when the arousal level is high. Is prohibited, so unnecessary alarms can be suppressed.

  As described in the second embodiment, since the white line is recognized from information that is not sufficient in the one-side recognition mode, the reliability of the white line information tends to decrease with time. When the reliability of the white line information is lower than a predetermined level, the alarm output based on the white line information is likely to become an unnecessary alarm.

  Therefore, in this embodiment, the white line information reliability A corresponding to the elapsed time of the one-side recognition mode is determined in advance, and compared with the white line information reliability B. The white line information reliability A is lower than the white line information reliability B. The lane keeping assist device 100 that prohibits the warning output will be described.

  FIG. 8A is a diagram illustrating an example of a relationship between the white line information reliability A and the white line information reliability B with respect to the elapsed time in the one-side recognition mode. The white line information reliability A is, for example, an average value of the deviation “length” of the deviation amount (length) between the actual position of the left white line 27 and the position of the recognized white line 28, and the passage of time. It is shown with.

The white line information reliability B is, for example, the reliability of white line information calculated based on the driver's arousal level and steering torque. While the driver's arousal level is high and the driver is steering to such an extent that steering torque is detected, it is considered that the vehicle 21 is traveling in the center of the traveling lane, and the traveling direction of the vehicle 21 is You can trust that it is along the lane. On the other hand, when the arousal level is low or the steering torque is not detected for a long time, the reliability of the correlation between the traveling direction of the vehicle 21 and the travel lane is lowered. Therefore, the white line information reliability B can be calculated as follows, for example.
White line information reliability B = α × wakefulness + β × time elapsed after detection of steering torque + γ
White line information reliability B = θ × wakefulness × steering torque detection elapsed time + ε
α to ε are coefficients for weighting the awakening level and the elapsed time after detection of the steering torque, and are determined so as to correlate with the absolute value of the white line information reliability A.

  FIG. 8B is a diagram illustrating an example of a functional block diagram of the lane keeping assist device 100. In FIG. 8B, the same components as those in FIG. 6B are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, the reliability calculation unit 47 includes a white line information reliability storage unit 48 that stores the white line information reliability A as shown in FIG. Then, the reliability calculation unit 47 calculates the white line information reliability from the closed eye measurement time detected by the arousal level detection unit 17 and the elapsed time after detection of the steering torque after the vehicle operation detection unit 42 detects the steering torque. B is calculated, and the white line information reliability A and the white line information reliability B are compared. Then, as shown in FIG. 8A, if the white line information reliability A is lower than the white line information reliability B, the alarm prohibition unit 46 determines that the white line information obtained by recognizing the white line on one side is not reliable enough. Prohibits alarm output.

  FIG. 9 is a flowchart showing a procedure in which the lane keeping assist device 100 prohibits the alarm output according to the relationship between the white line information reliability A and B. In FIG. 9, the same steps as those in FIG.

  The white line recognizing unit 12 recognizes the left and right white lines (S10). When both the left and right white lines can be recognized, the white line information is sent to the lane departure determining unit 43, and when only one white line is detected, the one side white line lost information is detected. Are output to the virtual line setting unit 44 (S20). When one of the left and right white lines cannot be recognized (No in S20), the lane departure determination unit 43 shifts to the one-side recognition mode, and the virtual line setting unit 44 sets the virtual line 23 (S30).

  Next, the reliability calculation unit 47 calculates the white line information reliability B (S210). That is, the white line information reliability B is calculated from the closed eye measurement time detected by the arousal level detection unit 17 and the elapsed time after detection of the steering torque. Then, the reliability calculation unit 47 compares the white line information reliability A and the white line information reliability B, and determines whether the white line information reliability A is equal to or higher than the white line information reliability B (S220).

  When the white line information reliability A is equal to or higher than the white line information reliability B (Yes in S220), the alarm prohibition unit 46 does not prohibit the alarm by the alarm request unit 45 (S160). On the other hand, if the white line information reliability A is not equal to or higher than the white line information reliability B (No in S220), the white line information obtained by recognizing the white line on one side is not sufficiently reliable, and the alarm prohibition unit 46 issues an alarm. The alarm by the request unit 45 is prohibited (S160).

  Therefore, when the one-side recognition mode continues for a long time and the white line information reliability A decreases, the warning is prohibited from being output, so that the lane departure determination unit 43 tends to deviate from the recognized white line 28 or the virtual line 23. Even if it determines, an unnecessary alarm can be suppressed.

  In this embodiment, the white line information reliability A and the white line information reliability B are compared. However, when the white line information reliability A is equal to or lower than a predetermined value, or the elapsed time from the one-side recognition mode is set as a threshold value. The alarm output may be prohibited when the degree of arousal is high and the arousal level is high.

  As described above, when only one of the left and right lane markings can be recognized, the lane keeping assist device 100 according to the present embodiment appropriately determines the deviation on the unrecognizable side to prevent unnecessary warning output and non-alarming. Can do.

It is an example of the block diagram of a lane maintenance assistance apparatus. It is an example of the functional block diagram of a lane keeping assistance apparatus. It is a figure explaining the virtual line which a lane maintenance assistance apparatus sets. It is a flowchart figure which shows the procedure in which a lane keeping assistance apparatus sets a virtual line according to the moving amount | distance of the vehicle width direction of a vehicle. It is a figure explaining the example of the unnecessary alarm which can arise in one side recognition mode. It is an example of the block diagram and functional block diagram of a lane keeping assistance apparatus. FIG. 4 is a flowchart showing a procedure for the lane keeping assist device to prohibit alarm output when the driver's arousal level is high and the recognized white line or virtual line changes in a direction different from the direction steered by the driver. is there. It is a figure which shows an example of the relationship between the white line information reliability A and the white line information reliability B with respect to the elapsed time of the one side recognition mode. It is a flowchart figure which shows the procedure in which a lane keeping assistance apparatus prohibits the output of a warning according to the relationship between white line information reliability A and B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Camera 12 White line recognition part 13 Torque sensor 14 Control part 15 Alarm device 16 Face camera 17 Arousal degree detection part 21 Vehicle 23-26 Virtual line 41 Virtual line correction part 42 Vehicle operation detection part 43 Lane departure determination part 44 Virtual line setting part 44 45 Alarm request section 46 Alarm prohibition section 47 Reliability calculation section

Claims (6)

In a lane keeping support device that detects a deviation tendency of at least one of the left and right lane markings of the host vehicle and warns an occupant,
A lane line recognition means for recognizing a lane line;
Vehicle operation detection means for detecting steering of the vehicle;
A virtual line setting means for setting a virtual line of the lane marking line on the undetectable side of the left and right lane marking lines;
A virtual line correcting means for moving the virtual line in the steering direction when the vehicle operation detecting means detects steering of the vehicle to a side that cannot be detected among the left and right lane division lines ;
When steering of the vehicle is detected by the vehicle operation detection means to the side that cannot be detected among the left and right lane markings, only the side that cannot be detected among the left and right lane markings is relaxed.
A lane keeping assist device characterized by that. The lane keeping assist device according to claim 1, wherein the virtual line correcting means moves the virtual line in a steering direction according to a movement amount in a vehicle width direction. The lane keeping assist device according to claim 2 , wherein the virtual line correcting means sets an upper limit on a moving speed of the virtual line. And alertness detection means for detecting the degree of awakening of luck rolling person,
When the lane marking or the imaginary line recognized in a direction different from the steering direction detected by the vehicle operation detection means is changed, and the arousal level detected by the awakening level detection unit is a predetermined value or more In the case of, warning prohibition means to prohibit the warning,
The lane keeping assist device according to claim 1, comprising: The warning prohibiting means prohibits a warning when the steering detected by the vehicle operation detecting means is in a straight traveling direction.
The lane keeping assist device according to claim 4, wherein A white line information reliability storage unit that stores reliability information A of the recognition result of the lane division line in association with the elapsed time after any of the left and right lane division lines is not detected,
The vehicle steering detected by the vehicle operation detecting means, and the reliability calculating means for calculating the reliability information B of the occupant steering based on the arousal level detected by the awakening level detecting means,
The warning prohibiting means prohibits a warning when the reliability information A is lower than the reliability information B.
The lane keeping assist device according to claim 4, wherein

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