JP2010244254A - Lane recognition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lane recognition device for reducing the period of time during which recognition of the relative position between a lane mark and a vehicle is stopped while securing high reliability of lane mark detection. <P>SOLUTION: The lane mark recognition device is equipped with a lane mark detecting unit 11 which captures an image of a road ahead of the vehicle by a camera 2 at predetermined control intervals to detect a lane mark, and adds detection data showing whether the lane mark has been detected or not to a ring buffer 14. When a traveling state detection means 15 detects that the vehicle has passed through an intersection, a lane position recognition means 13 recognizes the relative position between the vehicle and the lane mark even when a lane mark detection rate to be calculated from the data of the ring buffer 14 is equal to or less than a threshold, until a predetermined time elapses since it is detected that the vehicle passes the intersection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lane recognition device that detects a lane mark that divides a lane on a road and recognizes a relative position between the vehicle and the lane mark.

  Conventionally, a road image is acquired at a predetermined control cycle by a camera mounted on a vehicle, and a portion of image portion candidates of lane marks detected from each road image are collected for a short time, and the camera coordinates of each image portion are collected. A technique for calculating the relative distance between the lane mark and the host vehicle by converting the coordinates into real space coordinates has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 3538476

  In the above-described conventional technology, lane mark candidates are collected for a short period of time by collecting candidate lane mark image portions detected from road images acquired at successive control cycles, and converting them into real space coordinates. Recognizes real space position. In this case, as shown in FIG. 8, an average lane mark detection rate in the immediately preceding predetermined period is generally employed as a measure of the reliability of recognition of the real space position of the lane mark. .

In Figure 8, the result of the lane mark detection processing executed in each control cycle T _10, when the lane mark is detected shown in ○, and indicates when the lane mark is not detected in ×. Also, when the reliability of the lane mark detection is judged to be high and the relative position between the lane mark and the vehicle is recognized, a circle is shown, and the lane mark detection reliability is judged to be low. The case where the recognition of the relative position to the vehicle is stopped is indicated by x.

Regarding the reliability of lane mark detection, when the number of periods in which lane marks are detected is equal to or more than m in the period period (t _{11 to} t _p1 ) for n periods immediately before the determination time point t _p1 , Judging that the reliability of lane mark detection is high, the relative position between the lane mark and the vehicle is recognized.

In this case, when switching from a state where no lane mark is detected (a state where x continues, to t ₁₄ ) to a state where a lane mark is detected (shift from x to ○, t ₁₅ to), at least m Until the time corresponding to × T ₁₀ has elapsed, it is not determined that the reliability of lane mark detection has increased, and therefore, recognition of the relative position between the lane mark and the vehicle cannot be started.

  Therefore, for example, when a vehicle passes through an intersection, or when traveling on a branch or junction of a road, the vehicle travels temporarily where a lane mark is not laid, resulting in a decrease in reliability of lane mark detection. When the recognition of the relative position between the lane mark and the vehicle is stopped by the above, even if the lane mark is restored to the laid state after that, until the lane mark detection is judged to be highly reliable , Takes some time.

  In this case, the relative position between the lane mark and the vehicle is recognized even though the vehicle passes through an intersection, a road branch or junction, and the lane mark returns to a stable detectable state. Will continue to stop. For this reason, there is a disadvantage that the lane keeping control for assisting the steering to maintain the lane, the departure warning control from the lane, etc. cannot be resumed promptly.

  The present invention has been made in view of the above background, and can shorten the period in which the recognition of the relative position between the lane mark and the vehicle is stopped while ensuring high reliability of lane mark detection. An object is to provide a recognition device.

  The present invention has been made to achieve the above object, and a process for detecting a lane mark that distinguishes a lane of a road from a road image around the vehicle captured by a camera mounted on the vehicle is performed in a predetermined manner. Lane mark detection means executed for each control cycle, data holding means for sequentially adding and holding detection presence / absence data indicating the presence / absence of detection of lane marks in each control cycle, and latest data held in the data holding means Lane mark detection rate calculating means for calculating a lane mark detection rate, which is an average detection rate of lane marks, from the detection presence / absence data up to a predetermined number of times before the lane mark, and the lane mark detection rate having a predetermined reliability When the value is higher than the threshold value, the relative position between the vehicle and the lane mark is recognized based on the detection result of the lane mark by the lane mark detection unit. Pertaining to a lane recognition apparatus and a lane mark position recognizer.

  The vehicle includes a traveling state detection unit that detects that the vehicle has passed an intersection or road branch or junction, and the lane mark position recognition unit is configured to detect whether the vehicle is at an intersection or road branch by the traveling state detection unit. Alternatively, when it is detected that the vehicle has passed through the junction, the vehicle may be in a range from the time when the passage is detected until the predetermined condition is satisfied, even if the lane mark detection rate is equal to or less than the reliability threshold. The vehicle is recognized when the lane mark detection rate is equal to or less than the reliability threshold value except when the relative position between the lane mark and the lane mark is recognized and the predetermined condition is satisfied after the passage is detected. The recognition of the relative position between the lane mark and the lane mark is stopped.

  According to the present invention, the lane mark position recognizing means basically includes the lane mark detected by the lane mark detecting means only when the lane mark detection rate is higher than the reliability threshold. Recognizing the relative position to the vehicle increases the reliability of lane mark detection.

  When the traveling state detection means detects that the vehicle has passed an intersection, a road branch or a junction (hereinafter referred to as a lane mark non-installation location), the left and right lane marks of the road are stabilized thereafter. It is assumed that the state will be recovered. Therefore, when the lane mark position recognition means detects that the vehicle has passed through a lane mark non-installation location by the traveling state detection means, the lane mark position recognition means starts when the passage is detected until a predetermined condition is satisfied. In the meantime, the relative position between the vehicle and the lane mark is recognized even if the lane mark detection rate is not more than the reliability threshold value.

  Thereby, while maintaining the high reliability of lane mark detection, when the vehicle passes a lane mark non-installation location, the lane mark position recognition means recognizes the relative position between the vehicle and the lane mark. Can be resumed promptly.

  Further, the running condition detecting means may be configured such that the running condition detecting means detects a right or left lane mark by the lane mark detecting means from a lane mark detected state in which left and right lane marks of the road are detected by the lane mark detecting means. When switching to a lane mark non-detection state where at least one of the lane marks is not detected, the lane mark detection state is restored to the next lane mark detection state from the first time point when the lane mark detection state is switched to the lane mark non-detection state. The trajectory of the vehicle is calculated up to a second time point, and when the amount of change in the road width direction of the trajectory is equal to or less than a predetermined width direction change amount threshold, the vehicle is at an intersection or a road branch or merge It is characterized by detecting that the passage has passed.

  According to the present invention, the running condition detection means is from the first time point when the lane mark detection state is switched to the lane mark non-detection state until the second time point when the lane mark detection state is restored. The trajectory of the vehicle is calculated. When the amount of change in the trajectory of the vehicle in the road width direction is equal to or less than the width direction change amount threshold, the amount of movement of the vehicle in the road width direction is small, and the second time from the first time point It can be determined that the vehicle travels straight until the time. Therefore, in this case, the traveling state detection means can detect that the vehicle has passed a lane mark non-installation location.

  In addition, the travel condition detection unit is configured such that the amount of change in the road width direction of the trajectory is equal to or less than the width direction change amount threshold value, and the road detected by the lane mark detection unit immediately before the first time point. When the difference between the width between the left and right lane marks and the width between the left and right lane marks of the road detected by the lane mark detection means at the second time point is equal to or less than a predetermined road width change threshold value, It is detected that the vehicle has passed an intersection, a road branch or a junction.

  In this invention, the width between the left and right lane marks of the road detected by the lane mark detection unit immediately before the first time point, and the left and right sides of the road detected by the lane mark detection unit at the second time point. When the difference between the widths of the lane marks is equal to or smaller than the road width change threshold, it can be determined that the continuity of the lane marks before and after the lane mark non-detection state is high. Therefore, it is possible to improve the reliability of detection that the vehicle has passed a lane mark non-installation place by the traveling state detection means.

  A vehicle speed sensor for detecting a travel speed of the vehicle, wherein the travel condition detection means has a change amount in the road width direction of the trajectory equal to or less than the width direction change amount threshold value, and an intersection or road branch or From the first time point, more than the estimated transit time of an intersection or road branch or junction calculated using the estimated value of the passing distance of the junction and the traveling speed of the vehicle detected by the vehicle speed sensor When the elapsed time up to the second time point is short, it is detected that the vehicle has passed an intersection, a road branch or a junction.

  According to the present invention, for example, when a situation where a road lane mark is not provided due to road repair work or the like continues for more than the expected transit time, the lane mark position recognition means makes a relative relationship between the vehicle and the lane mark. Position recognition is not performed. Therefore, it is possible to improve the reliability of detection that the vehicle has passed a lane mark non-installation place by the traveling state detection means.

  Further, the travel condition detection means detects at least one of the left and right lane marks from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection means. From the first time point when the lane mark detection state is switched to the lane mark non-detection state to the second time point when the lane mark detection state is restored next When the vehicle trajectory of the vehicle is calculated and the amount of change in the direction of the trajectory between the first time point and the second time point is less than or equal to a predetermined traveling direction threshold, the vehicle is an intersection or road It is detected that it has passed through a branching or joining point.

  According to the present invention, the running state detection means is from the first time point when the lane mark detection state is switched to the lane mark non-detection state until the second time point when the lane mark detection state is subsequently restored. The trajectory of the vehicle is calculated. When the amount of change in the direction of the locus from the traveling direction of the vehicle at the first time point is equal to or less than the traveling direction threshold value, the change in the traveling direction of the vehicle is small, and the first time point To the second time point, it can be determined that the straight traveling performance of the vehicle is high. Therefore, in this case, the traveling state detection means can detect that the vehicle has passed through a branch / joining path not provided with at least one of an intersection or a right and left lane mark on the road.

  In addition, the travel condition detection unit may be configured such that the amount of change in the direction of the trajectory between the first time point and the second time point is equal to or less than the traveling direction threshold value and immediately before the first time point. The difference between the width between the left and right lane marks of the road detected by the lane mark detection means and the width between the left and right lane marks of the road detected by the lane mark detection means at the second time point is a predetermined value. When the vehicle width is less than or equal to the road width change threshold, it is detected that the vehicle has passed an intersection, a road branch or a junction.

  In this invention, the width between the left and right lane marks of the road detected by the lane mark detection unit immediately before the first time point, and the left and right sides of the road detected by the lane mark detection unit at the second time point. When the difference between the widths of the lane marks is equal to or smaller than the road width change threshold, it can be determined that the continuity of the lane marks before and after the lane mark non-detection state is high. Therefore, it is possible to improve the reliability of detection that the vehicle has passed a lane mark non-installation place by the traveling state detection means.

  Further, the vehicle is provided with a vehicle speed sensor that detects a traveling speed of the vehicle, and the traveling state detection unit has a change amount of the direction of the trajectory between the first time point and the second time point equal to or less than the traveling direction threshold value. And prediction of the intersection or road branch or junction calculated using the estimated value of the passage distance of the intersection or road branch or junction and the traveling speed of the vehicle detected by the vehicle speed sensor. When the elapsed time from the first time point to the second time point is shorter than the passing time, it is detected that the vehicle has passed an intersection, a road branch or a junction.

  According to the present invention, for example, when a situation where a road lane mark is not provided due to road repair work or the like continues for more than the expected transit time, the lane mark position recognition means makes a relative relationship between the vehicle and the lane mark. Position recognition is not performed. Therefore, it is possible to improve the reliability of detection that the vehicle has passed a lane mark non-installation place by the traveling state detection means.

  A vehicle speed sensor for detecting a traveling speed of the vehicle; and a yaw rate sensor for detecting a yaw rate of the vehicle, wherein the traveling state detecting means includes the traveling speed of the vehicle detected by the vehicle speed sensor, and the yaw rate. A trajectory of the vehicle from the first time point to the second time point is calculated using a yaw rate of the vehicle detected by a sensor.

  According to the present invention, the traveling direction of the vehicle is recognized from the yaw rate of the vehicle (angular acceleration around the vertical axis of the vehicle), the traveling distance of the vehicle is recognized from the traveling speed of the vehicle, and the vehicle A trajectory can be calculated.

  A torque sensor for detecting a torque applied to the steering of the vehicle, wherein the running condition detection unit is configured to detect the lane mark from a lane mark detection state in which left and right lane marks are detected by the lane mark detection unit; When the detection unit switches to a lane mark non-detection state in which at least one of the left and right lane marks is not detected, from the first time point when the lane mark detection state is switched to the lane mark non-detection state, Next, when the maximum value of the torque detected by the torque sensor is equal to or lower than a predetermined torque threshold until the second time point when the lane mark detection state is restored, or from the first time point to the second time point. The amount of change in torque detected by the torque sensor up to the point in time is a predetermined torque change amount threshold value or less. In the vehicle and detecting the passing through the branch or merge point of intersection or road.

  According to the present invention, when the torque detected by the torque sensor between the first time point and the second time point is equal to or less than the torque threshold value, the steering operation by the driver is gentle. Yes, it can be determined that the linearity of the vehicle between the first time point and the second time point is high. Therefore, in this case, the traveling state detection means can detect that the vehicle has passed a lane mark non-installation location.

  And a steering angle sensor for detecting a steering angle of the vehicle, wherein the traveling condition detection means detects the lane mark from a lane mark detection state in which left and right lane marks are detected by the lane mark detection means. When switching to a lane mark non-detection state in which at least one of the left and right lane marks is not detected by the means, from the first time point when the lane mark detection state is switched to the lane mark non-detection state, When the maximum steering angle detected by the steering angle sensor is less than or equal to a predetermined steering angle threshold until the second time point when the lane mark detection state is restored to the second time point, or the first The amount of change in the steering angle of the vehicle detected by the steering angle sensor from the time point to the second time point is a predetermined amount of steering angle change. When it is a value or less, the vehicle and detecting the passing through the branch or merge point of intersection or road.

  According to the present invention, when the steering angle detected by the rudder angle sensor between the first time point and the second time point is equal to or less than the rudder angle threshold value, the steering of the driver is performed. It can be determined that the amount of operation is small and that the vehicle is traveling straight from the first time point to the second time point. Therefore, in this case, the traveling state detection means can detect that the vehicle has passed a lane mark non-installation location.

  The vehicle includes at least a pair of left and right wheels, and includes a rotational speed difference detecting unit that detects a rotational speed difference between the left and right wheels, and the traveling state detecting unit is configured to detect the right and left of the road by the lane mark detecting unit. When the lane mark detection state is detected, the lane mark detection state is switched to a lane mark non-detection state in which at least one of the left and right lane marks is not detected by the lane mark detection unit. The rotation of the left and right wheels detected by the rotational speed difference detecting means from the first time point when the lane mark detection state is switched to the second time point when the lane mark detection state is restored next. Detecting the rotational speed difference when the maximum value of the speed difference is less than or equal to a predetermined rotational speed difference threshold or between the first time point and the second time point Detecting that the vehicle has passed an intersection, road branch or junction when the amount of change in the rotational speed difference between the left and right wheels detected by the step is less than or equal to a predetermined wheel speed difference change amount threshold. It is characterized by.

  According to the present invention, the speed difference between the left and right wheels of the vehicle detected by the rotational speed difference detecting means changes in accordance with a change in the traveling direction of the vehicle (degree of bending). Therefore, the difference between the rotation speeds of the left and right wheels detected by the rotation speed difference detection means between the first time point and the second time point, or the change amount thereof is not more than the wheel speed difference change amount threshold value. In some cases, it can be determined that the straight traveling performance of the vehicle from the first time point to the second time point is high. Therefore, in this case, the traveling state detection means can detect that the vehicle has passed a lane mark non-installation location.

  Further, the travel condition detection means detects at least one of the left and right lane marks from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection means. Based on the detection result of the lane mark by the lane mark detection means immediately before the first time point when the lane mark detection state is switched to the lane mark non-detection state Based on the relative position between the vehicle and the lane mark detected by the lane mark position recognizing means, and the detection result of the lane mark by the lane mark detecting means at the second time point when the lane mark detecting state is switched to the next lane mark detecting state. The vehicle and the lane mark detected by the lane mark position recognition means The difference between the relative position of, when it is less than the predetermined relative position difference threshold, the vehicle and detecting the passing through the branch or merge point of intersection or road.

  According to the present invention, the difference between the relative position between the vehicle and the lane mark immediately before the first time point and the relative position between the vehicle and the lane mark at the second time point is the relative position difference. When the value is equal to or less than the threshold value, there is little change in the width between the lane marks at the first time point and the second time point, and the vehicle travels straight from the first time point to the second time point. Can be determined to be high. Therefore, in this case, the traveling state detection means can detect that the vehicle has passed a lane mark non-installation location.

Explanatory drawing which showed the mounting aspect to the vehicle of the lane recognition apparatus of this invention. The block diagram of the lane recognition apparatus shown in FIG. Explanatory drawing of a ring buffer. The flowchart of the judgment of the reliability of intersection passing and lane mark detection, and the relative position recognition of a vehicle and a lane mark. Explanatory drawing of the locus | trajectory of a vehicle when passing an intersection. The timing chart of the lane mark detection corresponding to the locus | trajectory of the vehicle shown in FIG. 6, and the relative position recognition of a vehicle and a lane mark. Explanatory drawing of the condition where a vehicle passes the branch location and junction location of a road. Explanatory drawing of the reliability judgment of a lane mark detection.

  An example of an embodiment of the present invention will be described with reference to FIGS. Referring to FIG. 1, a lane recognition device 10 is used by being mounted on a vehicle 1 (vehicle of the present invention), and classifies a traveling lane from a road image captured by a camera 2 that images the front of the vehicle 1. For this purpose, the lane mark laid on the road is detected and the relative position between the lane mark and the vehicle 1 is recognized.

  Data on the relative position between the lane mark recognized by the lane recognition device 10 and the vehicle 1 is output to an ECU (Electronic Control Unit) 30 of the vehicle 1. Based on the relative position between the lane mark and the vehicle 1, the ECU 30 performs lane maintenance control for assisting the steering 5 so that the vehicle 1 is maintained in the traveling lane, and a situation where the vehicle 1 is likely to deviate from the traveling lane. When this happens, lane departure warning control is performed to issue a warning (by voice output from a speaker (not shown), etc.).

  Further, the vehicle 1 includes a vehicle speed sensor 20 that detects the traveling speed of the vehicle 1, a yaw rate sensor 21 that detects angular acceleration around the vertical axis of the vehicle 1, a steering angle sensor 22 that detects the steering angle of the steering 5, and steering A torque sensor 23 for detecting the torque applied to 23 is provided.

  Next, referring to FIG. 2, the lane recognition device 10 recognizes lane marks (white line, yellow line, cat's eye, Bots Dots, etc.) from the road image in front of the vehicle captured by the camera 2 at each control period. Lane mark detection means 11 to detect, ring buffer 14 (corresponding to the data holding means of the present invention) in which detection presence / absence data indicating the presence / absence of lane mark detection by the lane mark detection means 11 is sequentially written and held, and a ring Lane mark detection rate calculation means 12 for calculating a lane mark detection rate, which is an average detection rate of lane marks, from detection presence / absence data held in the buffer 14, and a lane mark for recognizing the relative position between the vehicle and the lane mark Position recognition means 13 and traveling condition detection means 15 for detecting that the vehicle 1 has passed the intersection are provided.

  The lane recognition device 10 is an electronic unit composed of a microcomputer or the like, and by causing the microcomputer to execute a lane recognition program, the microcomputer recognizes the lane mark detection means 11 and the lane mark detection rate calculation means 12. , Function as lane mark position recognition means 13 and running condition detection means 15. In addition, detection signals from the vehicle speed sensor 20, the yaw rate sensor 21, the steering angle sensor 22, and the torque sensor 23 are input to the lane recognition device 10.

  As shown in FIG. 3, the ring buffer 14 has a capacity to hold 30 detection presence / absence data (array elements a [1], a [2],..., A [30]). The newly added detection presence / absence data is held in a [1], and the data previously held in a [1] is shifted to a [2]. Similarly, data held in a [2], a [3],..., A [29] until then are shifted to a [3], a [4],. The data held in a [30] until then is discarded.

  Next, the operation of the lane recognition device 10 will be described according to the flowchart shown in FIG. The lane recognition device 10 repeatedly executes the processing of STEP 1 to STEP 7 in FIG. 4 at every predetermined control cycle.

  First, the lane recognition device 10 captures an image of a road ahead of the vehicle by the camera 2 in STEP1. The subsequent STEP 2 is processing by the lane mark detection means 11. The lane mark detection unit 11 detects a lane mark by performing straight line extraction processing such as Hough transform on the edge point extracted from the road image. The lane mark detection unit 11 adds detection presence / absence data indicating whether or not a lane mark is detected to the ring buffer 14.

  In the next STEP 3, the lane recognition device 10 determines whether or not the image portion of the lane mark has been detected. When the lane mark image portion is detected, the process proceeds to STEP 3, and when the lane mark image portion is not detected, the process proceeds to STEP 8, and the process is terminated.

  In subsequent STEP 4, it is determined whether or not the vehicle 1 is within a predetermined time from the time when the vehicle 1 passes the intersection. Here, detection that the vehicle 1 has passed the intersection is executed by the traveling state detection means 15, and whether or not the vehicle 1 is within a predetermined time from when the vehicle 1 passed the intersection is determined by the lane mark position recognition means 13. It is executed by. Note that the passage of the predetermined time in STEP 4 corresponds to the predetermined condition of the present invention.

  In addition, the detection process that the vehicle 1 passed the intersection by the driving | running | working condition detection means 15 is mentioned later. The predetermined time in STEP 4 is set assuming that the lane mark detection rate Rt calculated by the lane mark detection rate calculation means 12 is higher than the reliability threshold value Rth.

  If a predetermined time has elapsed since the vehicle 1 passed the intersection in STEP4, the process proceeds to STEP5. STEP 5 is a process performed by the lane mark detection rate calculation unit 12. The lane mark detection rate calculation unit 12 calculates the lane mark detection rate Rt according to the following equation (1).

  Where Rt: average lane mark detection rate for n array elements from the latest addition, n: total number of array elements in the ring buffer (30 in this embodiment), m: lane mark detection The number of array elements in the ring buffer that holds detection presence / absence data indicating existence.

  The following STEP 6 to STEP 7 are processes by the lane mark position recognition means. In STEP 6, the lane mark position recognition unit 13 determines whether or not the lane mark detection rate Rt is higher than the reliability determination value Rth.

  When the lane mark detection rate Rt is higher than the reliability determination value Rth, the process proceeds to STEP 7, where the lane mark position recognition unit 16 determines the vehicle 1 in the real space based on the detection result of the lane mark by the lane mark detection unit 11. Recognizes the relative position to the lane mark. The lane mark position recognizing means 16 transmits the data of the relative position to the ECU 30 and proceeds to STEP8, where the lane recognition device 10 ends the process of one control cycle.

  On the other hand, if the lane mark detection rate Rt is less than or equal to the reliability judgment value Rth in STEP6, the process branches to STEP8. In this case, the recognition of the relative position between the vehicle 1 and the lane mark by the lane mark position recognition unit 13 is not executed, and the lane recognition device 10 ends the process of one control cycle.

  If it is within a predetermined time from the time when the vehicle 1 passes through the intersection in STEP4, the process proceeds to STEP7. In this case, it is not determined whether or not the lane mark detection rate Rt in STEP 5 to STEP 6 is higher than the reliability threshold value Rth. In STEP 7, the lane mark position recognition unit 13 determines whether the vehicle 1 and the lane mark are The relative position is calculated.

  Here, FIG. 5 shows the trajectory of the vehicle 1 when passing the intersection, and t1 is a state where the left and right lane marks 50L, 50R of the vehicle 1 are detected (lane mark detection state). A time point when the lane marks 50R and 50L are switched to a state where the lane marks 50R and 50L are not detected (lane mark non-detected state) is shown.

  Further, t3 indicates a time point when the lane mark non-detection state is switched to the lane mark detection state. T5 is limited to when the lane mark detection rate Rt is higher than the reliability threshold Rth, as in the conventional lane recognition device, and when the relative position between the vehicle 1 and the lane mark is recognized. From the state where the recognition process of the relative position between the vehicle 1 and the lane mark is not executed by the lane mark position recognition unit 13 (the lane mark position is not recognized), the recognition process of the relative position between the vehicle 1 and the lane mark is executed. The time point when the state is switched to the lane mark recognition state (lane mark position recognition state) is shown.

  Here, FIG. 6 is a timing chart of the situation shown in FIG. 5, in which the lane mark detection state and the lane mark non-detection state are switched in order from the top, and the lane mark position recognition state and lane mark in the conventional lane recognition device. This shows switching of the position unrecognized state and switching of the lane mark position recognized state and the lane mark position unrecognized state in the lane recognition device of the present embodiment.

  In FIG. 6, t2 is the time when the lane mark position recognition state is switched to the lane mark position non-recognition state, and t4 is the time point when the lane mark position non-recognition state is switched to the lane mark position recognition state.

  In the conventional lane recognition device, it is necessary to wait for the lane mark detection rate Rt to be higher than the reliability threshold value Rth when the vehicle 1 passes through the intersection and switches from the lane mark non-detection state to the lane mark detection state. There is. Therefore, the time from t3 when the vehicle 1 passes the intersection and switches from the lane mark non-detection state to the lane mark detection state to t5 when the lane mark non-recognition state switches to the lane mark recognition state becomes long. Until t5, the above-described lane keeping control and lane departure warning control by the ECU 30 are not executed.

  On the other hand, in the present embodiment, the lane mark position recognizing means 13 is within a predetermined time from when it is detected that the vehicle 1 has passed the intersection even if the lane mark detection rate Rt is less than or equal to the reliability threshold value Rth. Thus, the relative position between the vehicle 1 and the lane mark is recognized. Therefore, the calculation of the relative position between the vehicle 1 and the lane mark can be quickly restarted at t4 when a delay time by calculation is added to t3 when the vehicle 1 passes the intersection.

  Next, a description will be given of a first embodiment of a detection process performed by the traveling state detection unit 15 to detect that the vehicle 1 has passed an intersection. Referring to FIG. 5, the traveling state detection means 15 next switches to the lane mark detection state from t1 (corresponding to the first time point of the present invention) after switching from the lane mark detection state to the lane mark non-detection state. The trajectory 60 of the vehicle 1 is calculated until t3 (corresponding to the second time point of the present invention) after switching.

  Specifically, the traveling state detection unit 15 calculates the locus 60 of the vehicle 1 from the traveling speed of the vehicle 1 detected by the vehicle speed sensor 20 and the yaw rate of the vehicle 1 detected by the yaw rate sensor 21. When the following conditions (1) and (2) are satisfied, it is detected that the vehicle 1 has passed the intersection.

  (1) The change amount of the trajectory 60 in the road width direction at t1 is a predetermined width direction change amount threshold value (for example, about 17% of the width between the lane marks 50R and 50L (0.6m if the width is 3.6m) ) Set below.

  (2) The difference between the width between the lane marks 50R and 50L at t1 and the width between the lane marks 51R and 51L at t3 is a predetermined road width change threshold (for example, 10% of the width between the lane marks 51R and 51L). (Set to about ± 0.36 m if the width is 3.6 m)) or less.

  Note that it may be detected that the vehicle 1 has passed the intersection using only the condition (1). Further, by adding the following condition (3) as a condition for detecting that the vehicle 1 has passed the intersection, the detection accuracy of the intersection passing can be improved.

  (3) The elapsed time from t1 to t3 is calculated by dividing the estimated passing distance of the intersection by the traveling speed of the vehicle 1, and is less than the expected passing time.

  Moreover, you may employ | adopt the following 2nd form-a 9th form as a detection process by the driving condition detection means 15 that the vehicle 1 passed the intersection.

  [Second Embodiment] The traveling state detection means 15 detects that the vehicle 1 has passed an intersection when the following conditions (4) and (2) are satisfied.

  (4) The amount of change in the direction of the trajectory 60 of the vehicle 1 from t1 to t3 is a predetermined traveling direction threshold (for example, 1.2 degrees (if the width of the intersection is 25 m, the vehicle 1 travels through the intersection) The amount of movement in the horizontal direction is 0.5 m) or less.

  Note that it may be detected that the vehicle 1 has passed the intersection using only the condition (4). Further, by adding the condition (3) as a condition for detecting that the vehicle 1 has passed the intersection, the detection accuracy of the intersection passing can be increased.

  [Third Embodiment] The traveling state detection means 15 detects that the vehicle 1 has passed an intersection when the following condition (5) or (6) is satisfied.

  (5) Between t1 and t3, the maximum value of the torque (absolute value) applied to the steering wheel 5 detected by the torque sensor 23 is not more than a predetermined torque threshold.

  (6) Between t1 and t3, the amount of change in torque applied to the steering wheel 5 detected by the torque sensor 23 is equal to or less than a predetermined torque change amount threshold. Note that an integral value of the square value of the torque detected by the torque sensor 23 may be used as the torque change amount.

  [Fourth Embodiment] The traveling state detection means 15 detects that the vehicle 1 has passed an intersection when the following condition (7) or (8) is satisfied.

  (7) Between t1 and t3, the maximum value of the steering angle (absolute value) of the steering wheel 5 detected by the steering angle sensor 22 is equal to or less than a predetermined steering angle threshold value.

  (8) Between t1 and t3, the change amount of the steering angle of the steering wheel 5 detected by the steering angle sensor 22 is equal to or less than a predetermined steering angle change amount threshold value.

  [Fifth Embodiment] The traveling state detection means 15 detects that the vehicle 1 has passed an intersection when the following condition (9) or (10) is satisfied.

  (9) Between t1 and t3, the rotational speed difference between the left and right front wheels of the vehicle 1 is less than a predetermined rotational speed difference threshold. Here, the difference between the rotational speeds of the left and right front wheels is obtained by arithmetic processing in the lane recognition device 10 or the ECU 30 based on the detection signal of the rotational speed of the right front wheel and the detection signal of the rotational speed of the left front wheel by the vehicle speed sensor 20. It is done. In addition, the structure which calculates | requires the rotational speed difference of a front wheel on either side corresponds in this way to the rotational speed difference detection means of this invention.

  (10) Between t1 and t3, the amount of change in the rotational speed difference between the left and right front wheels of the vehicle 1 is less than or equal to a predetermined rotational speed difference threshold.

  [Sixth Embodiment] The traveling state detection means 15 detects that the vehicle 1 has passed an intersection when the following condition (11) is satisfied.

  (11) Based on the detection result of the lane mark immediately before t1, the lane mark position recognition means 13 recognizes the relative position between the vehicle 1 and the lane mark, and the lane mark detection result at t3. The difference between the relative position of the vehicle 1 recognized by the mark position recognition means 13 and the lane mark is equal to or less than a predetermined relative position difference threshold.

  In the first to sixth embodiments described above, the vehicle 1 is limited to an intersection when the traveling speed of the vehicle 1 is equal to or less than a traveling speed threshold assuming a traveling speed on a general road with an intersection. You may make it detect having passed.

  Moreover, in the said 1st Embodiment-6th Embodiment, only when the driving speed of the vehicle 1 is more than the minimum speed which performs the said lane maintenance control and the said lane departure warning control, the vehicle 1 makes an intersection. You may make it detect that it passed.

  Further, in the present embodiment, it is detected that the vehicle 1 has passed the intersection. However, as shown in FIG. 7A, the left and right lane marks are also detected when the vehicle 1 passes through a branch point of the road. There is a section A1 in which one of 70R and 70L is not detected.

  Similarly, as shown in FIG. 7B, there is a section A2 in which one of the left and right lane marks 71R and 71L is not detected even when the vehicle 1 passes through the junction of the road. Therefore, the lane keeping control and the lane departure warning control cannot be executed even when passing through a road branch or junction.

  Therefore, it may be detected that the vehicle 1 has passed a branch or junction of the road in the same manner as the detection that the vehicle 1 has passed the intersection. When it is detected that the vehicle 1 has passed through a road branch or junction, even if the lane mark detection rate is equal to or less than the reliability threshold within a predetermined time from the time when the vehicle 1 passes through the road branch or junction. By recognizing the relative position between the vehicle 1 and the lane mark, the time during which the lane position control and the lane departure warning control are stopped can be shortened.

  In the present embodiment, even if the lane mark detection rate Rt is equal to or less than the reliability threshold value Rth, as a condition for recognizing the relative position between the vehicle 1 and the lane mark (corresponding to the predetermined condition of the present invention), The predetermined time was set from the time when the vehicle 1 passed the intersection. However, as the predetermined condition of the present invention, for example, until the vehicle 1 travels a predetermined distance (set assuming a distance at which the lane mark detection rate Rr is higher than the reliability threshold Rth) from the time when the vehicle 1 passes the intersection. Alternatively, the time from when the vehicle 1 passes through the intersection until the lane mark detection rate Rt becomes higher than the reliability threshold value Rth may be set.

  In the present embodiment, the fact that the vehicle 1 has passed the intersection is detected based on whether or not the lane mark is detected and the detection values obtained by various sensors such as the vehicle speed sensor 20. When a Positioning System) is provided, it may be detected that the vehicle 1 has passed the intersection using GPS and map data.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Camera, 10 ... Lane recognition apparatus, 11 ... Lane mark detection means, 12 ... Lane mark detection rate calculation means, 13 ... Lane mark position recognition means, 14 ... Ring buffer, 15 ... Travel condition detection means, 30 ... ECU, 20 ... vehicle speed sensor, 21 ... yaw rate sensor, 22 ... rudder angle sensor, 23 ... torque sensor

Claims (12)

Lane mark detection means for executing processing for detecting a lane mark for dividing a lane of a road from a road image around the vehicle imaged by a camera mounted on the vehicle for each predetermined control period;
Data holding means for sequentially adding and holding detection presence / absence data indicating the presence / absence of detection of lane marks in each control cycle;
Lane mark detection rate calculating means for calculating a lane mark detection rate, which is an average detection rate of lane marks, from the detection presence / absence data up to a predetermined number of minutes before the latest one held in the data holding unit;
Lane mark position recognition means for recognizing a relative position between the vehicle and the lane mark based on a detection result of the lane mark by the lane mark detection means when the lane mark detection rate is higher than a predetermined reliability threshold value. A lane recognition device comprising:
A traveling state detection means for detecting that the vehicle has passed through an intersection or a road branch or junction,
The lane mark position recognizing means satisfies a predetermined condition from the time when the passage is detected when the traveling state detecting means detects that the vehicle has passed an intersection, a road branch or a junction. Until the lane mark detection rate is less than or equal to the reliability threshold, the relative position between the vehicle and the lane mark is recognized, and from when the passage is detected until the predetermined condition is satisfied. Outside the interval, when the lane mark detection rate is equal to or less than the reliability threshold, the recognition of the relative position between the vehicle and the lane mark is stopped. The lane recognition device according to claim 1,
The lane mark detection unit detects a lane in which at least one of the left and right lane marks is not detected from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection unit. When switching to the mark non-detection state, the first time point when the lane mark detection state is switched to the lane mark non-detection state until the second time point when the lane mark detection state is restored next. Calculate the trajectory of the vehicle,
A lane recognition device, wherein when the amount of change in the road width direction of the trajectory is equal to or less than a predetermined width direction change amount threshold, the vehicle detects that the vehicle has passed an intersection, a road branch or a junction. The lane recognition device according to claim 2,
The travel condition detection means has a change amount in the road width direction of the trajectory that is equal to or less than the width direction change amount threshold value, and the right and left of the road detected by the lane mark detection means immediately before the first time point. When the difference between the width between lane marks and the width between the left and right lane marks detected by the lane mark detection means at the second time point is equal to or less than a predetermined road width change threshold, A lane recognition device that detects that the vehicle has passed through an intersection, a road branch or a junction. The lane recognition device according to claim 2,
A vehicle speed sensor for detecting the traveling speed of the vehicle;
The travel state detection means detects the amount of change in the road width direction of the trajectory below the width direction change amount threshold, and is detected by an estimated value of the passing distance of an intersection or a road branch or junction, and the vehicle speed sensor. When the elapsed time from the first time point to the second time point is shorter than the expected transit time of the intersection or road branch or merge point calculated using the travel speed of the vehicle, A lane recognition device for detecting that a vehicle has passed an intersection, a road branch or a junction. The lane recognition device according to claim 1,
The lane mark detection unit detects a lane in which at least one of the left and right lane marks is not detected from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection unit. When switching from the lane mark detection state to the lane mark non-detection state when switching to the mark non-detection state, the period from the first time point when the lane mark detection state is restored to the second lane mark detection state. Calculate the trajectory of the vehicle,
When the amount of change in the direction of the trajectory between the first time point and the second time point is equal to or less than a predetermined traveling direction threshold, the vehicle has passed an intersection, a road branch, or a junction. A lane recognition device characterized by detecting. The lane recognition device according to claim 5,
The travel condition detection means has a change amount of the direction of the trajectory between the first time point and the second time point that is not more than the traveling direction threshold value, and the lane immediately before the first time point. The difference between the width between the left and right lane marks of the road detected by the mark detection means and the width between the left and right lane marks of the road detected by the lane mark detection means at the second time point is a predetermined road. A lane recognition device that detects that the vehicle has passed an intersection, a road branch or a junction when the width change threshold value is not greater than the threshold. The lane recognition device according to claim 5,
A vehicle speed sensor for detecting the traveling speed of the vehicle;
The travel condition detection means has an amount of change in the direction of the trajectory between the first time point and the second time point that is equal to or less than the traveling direction threshold value, and passes through an intersection or a road branch or junction. From the first time point to the second time, the estimated passing time of an intersection or road branch or junction calculated using the estimated value of the distance and the traveling speed of the vehicle detected by the vehicle speed sensor. A lane recognition device that detects that the vehicle has passed through an intersection, a road branch or a junction when the elapsed time to the time is short. In the lane recognition device according to any one of claims 2 to 7,
A vehicle speed sensor for detecting a traveling speed of the vehicle;
A yaw rate sensor for detecting the yaw rate of the vehicle,
The traveling state detection means uses the traveling speed of the vehicle detected by the vehicle speed sensor and the yaw rate of the vehicle detected by the yaw rate sensor, from the first time point to the second time point. A lane recognition device that calculates a trajectory of the vehicle in between. The lane recognition device according to claim 1,
A torque sensor for detecting torque applied to the steering of the vehicle;
The lane mark detection unit detects a lane in which at least one of the left and right lane marks is not detected from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection unit. From the first time point when the lane mark detection state is switched to the lane mark non-detection state to the second time point when the lane mark detection state is restored to When the maximum value of the torque detected by the torque sensor is equal to or less than a predetermined torque threshold, or between the first time point and the second time point, the amount of change in the torque detected by the torque sensor is Detecting that the vehicle has passed an intersection, road branch or junction when the torque change amount threshold value is less than or equal to Lane recognition device according to claim. The lane recognition device according to claim 1,
A steering angle sensor for detecting a steering angle of the vehicle;
The lane mark detection unit detects a lane in which at least one of the left and right lane marks is not detected from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection unit. From the first time point when the lane mark detection state is switched to the lane mark non-detection state to the second time point when the lane mark detection state is restored to When the maximum value of the steering angle of the vehicle detected by the steering angle sensor is equal to or less than a predetermined steering angle threshold, or between the first time point and the second time point, the steering angle sensor When the detected change amount of the steering angle of the vehicle is equal to or less than a predetermined steering angle change amount threshold, the vehicle is an intersection or a road branch or Lane recognition apparatus characterized by sensing the passing flow portions. The lane recognition device according to claim 1,
The vehicle has at least a pair of left and right wheels,
A rotational speed difference detecting means for detecting a rotational speed difference between the left and right wheels;
The lane mark detection unit detects a lane in which at least one of the left and right lane marks is not detected from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection unit. From the first time point when the lane mark detection state is switched to the lane mark non-detection state to the second time point when the lane mark detection state is restored to When the maximum value of the rotational speed difference between the left and right wheels detected by the rotational speed difference detecting means is equal to or less than a predetermined rotational speed difference threshold value, or between the first time point and the second time point. When the amount of change in the rotational speed difference between the left and right wheels detected by the rotational speed difference detection means is equal to or less than a predetermined wheel speed difference change amount threshold, Lane recognition apparatus characterized by sensing the passing through the branch or merge point satin or road. The lane recognition device according to claim 1,
The lane mark detection unit detects a lane in which at least one of the left and right lane marks is not detected from the lane mark detection state in which the left and right lane marks of the road are detected by the lane mark detection unit. When switching to the mark non-detection state,
The vehicle detected by the lane mark position recognizing unit based on the lane mark detection result by the lane mark detecting unit immediately before the first time point when the lane mark detected state is switched to the lane mark non-detected state. The vehicle detected by the lane mark position recognizing means based on the relative position to the lane mark and the detection result of the lane mark by the lane mark detecting means at the second time point when the lane mark is next switched to the lane mark detecting state. A lane recognition device that detects that the vehicle has passed an intersection, a road branch or a junction when the difference between the relative position of the vehicle and the lane mark is equal to or less than a predetermined relative position difference threshold.

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