JP2011227551A - Meander driving detection device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a meander driving detection device for a vehicle, which prevents erroneous detection and also detects even comparatively small meander when a situation is the abnormal one concerning meander driving detection.SOLUTION: The meander driving detection device for a vehicle includes lateral position detection means for detecting lateral position relation between a lane and the vehicle on the vehicle; and abnormality detection means for identifying presence/absence of an abnormality in meander driving, based on a change in the position relation. The device also includes statistic value output means 3a-11 for obtaining and outputting a statistic value corresponding to a time sequential change concerning the detected lateral position; lane change detection means 3a-13 for detecting presence/absence of a lane change expressing a movement by crossing between a plurality of lanes; and statistic value initialization means 3a-12 for initializing the statistic value of the statistic value output means when the lane change detection means detects existence of the lane change. Abnormality detection means 3a-7 identifies presence/absence of the abnormality in the meander driving, based on the latest statistic value to be outputted by the statistic value output means.

Description

  The present invention recognizes a lane (runnable lane) of a road on which the vehicle travels on a vehicle and detects a lateral positional relationship between the lane and the vehicle, The present invention relates to a meandering operation detecting device for a vehicle including abnormality detecting means for identifying presence / absence of abnormality such as meandering operation based on a change.

  As a prior art related to the vehicle meandering operation detecting apparatus of the present invention, a technique disclosed in Patent Document 1 is known. In Patent Document 1, a subject such as a road surface behind a running vehicle is continuously photographed by a vehicle-mounted camera, and the obtained image is processed to display a white line or FOE (Focus of Expansion) displayed on the road surface. Recognize points, further determine the optical flow, grasp the positional relationship between the lane and the vehicle (position relative to the lane relative to the lane), determine whether there is lane departure or meandering, and issue an alarm .

  Here, the FOE point is also referred to as an infinite point, for example, specified as the same position as the point where an extension line extending from a pair of white lines located on both sides of the own lane on the road surface on which the own vehicle should travel intersect. can do. Although the forward image of the camera mounted on the traveling vehicle changes from moment to moment, a velocity vector (optical flow) can be obtained by connecting the same corresponding points with straight lines in the images at time t and time t + Δt. All optical flows appear radially from one point in the image. This one point is the FOE point.

  The positional relationship (lateral position) between the lane and the vehicle can be obtained as follows as an example. A perpendicular line extending from the FOE point is defined as a reference line, and angles formed by the reference line and a pair of white lines at both ends of the lane in which the vehicle is traveling are defined as θ1 and θ2, and the difference between these angles (θ1−θ2) The lateral position can be determined. For example, if the angle difference (θ1−θ2) is 0, the position of the vehicle is approximately in the center of the lane, and if the vehicle is traveling to the left as viewed from the camera to be photographed, ((θ1 −θ2) <0), and ((θ1−θ2)> 0) if the vehicle is traveling rightward as viewed from the camera.

  Further, as disclosed in Patent Document 1, if the time-series change of the detected lateral position of the vehicle is analyzed, an abnormal state such as wobbling of the vehicle position in the lane, that is, meandering operation is detected. An alarm can be automatically issued.

Conventional techniques related to the present invention are also disclosed in Patent Documents 2 to 4.
Patent Document 2 is a technique related to a road monitoring device, which processes an image obtained by a camera that captures a road, detects a travel locus of a vehicle, and may detect an obstacle from a change such as a lane change of the vehicle. Suggests to identify.

  In the technique of Patent Literature 3, a subject such as a road surface on the front side of a running vehicle is continuously photographed by an in-vehicle camera, the obtained image is processed to recognize a white line on the road surface, and the lateral position of the vehicle. The driver's situation (awakening level) is estimated based on the degree of wobbling. Also, a technique for correctly recognizing a lane when a plurality of types of lines such as white lines displayed on the road surface are mixed is proposed.

  In the technique of Patent Document 4, a subject such as a road surface on the rear side of a running vehicle is continuously photographed by an in-vehicle camera, and the obtained image is processed to recognize a white line on the road surface. A lane departure tendency is detected from the positional relationship in the lateral direction. In addition, a technique for correctly grasping the positional relationship even when the road is curved or the vehicle is tilted toward one of the white lines is proposed.

JP 2000-276697 A Japanese Patent Laid-Open No. 10-91893 JP 2002-163642 A JP 2007-200191 A

  As disclosed in Patent Document 1, if the time-series change of the detected lateral position of the vehicle is analyzed, it is possible to detect an abnormal state such as a wobbling of the vehicle position in the lane, that is, a meandering operation. Is possible. However, the environment in which the vehicular meandering detection device is used varies, and the conventional technology cannot be said to have sufficiently high accuracy in detecting wobbling of the vehicle position or meandering.

  For example, on a road with a plurality of lanes where the vehicle can travel, such as an expressway, the driver moves from the currently driving lane to another lane adjacent to it (hereinafter referred to as “lane”). Change ”). On the other hand, when the driver's attention is reduced or when an abnormal situation such as snoozing occurs, the vehicle moves unconsciously to a position that crosses multiple lanes or performs meandering Such a situation can occur. It is very difficult to automatically distinguish such an intentional “lane change” of a driver from an anomaly such as unconscious meandering.

  In addition, when the driver intentionally performs “lane change”, the record remains as a time-series change of the past lateral position of the vehicle, which becomes an obstacle when determining whether the driving is meandering. As a result, the vehicle meandering operation detection device may generate a warning of meandering operation even though the meandering operation is not actually performed. On the other hand, in order to prevent such a malfunction, if the threshold value for determining the meandering operation is set to be large, even if the meandering operation is actually performed, the meandering operation can be detected when the degree of staggering is small. Or there will be a large time delay in detection. Therefore, there is a high possibility that an alarm for avoiding the occurrence of an accident will not be in time.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention relates to detection of an abnormal state such as a meandering operation, and prevents occurrence of erroneous detection. Even so, an object of the present invention is to provide a vehicular meandering detection device that can be detected as meandering.

In order to achieve the above-described object, the vehicle meandering operation detecting device according to the present invention is characterized by the following (1) to (5).
(1) On the vehicle, a lateral position detecting means for recognizing a lane of a road on which the vehicle travels and detecting a lateral positional relationship between the lane and the vehicle; meandering based on the change in the positional relationship A meandering driving detection device for a vehicle provided with an abnormality detection means for identifying the presence or absence of an abnormality in driving,
Statistical value output means for obtaining and outputting a statistical value according to a time-series change related to the horizontal position detected by the horizontal position detection means;
Lane change detection means for detecting the presence or absence of a lane change indicating that the vehicle has moved across a plurality of adjacent lanes;
A statistical value initializing unit that initializes a statistical value of the statistical value output unit when the lane change detecting unit detects that there is a lane change, and the abnormality detection unit outputs the statistical value output unit Identify the presence of abnormal meandering based on the latest statistics.
(2) The vehicle meandering operation detecting device according to (1),
A blinker signal monitoring means for monitoring a state of a blinker signal representing a signal of a lane change by a driver's operation,
The statistical value initialization means, when the blinker signal appears, when the lane change detection means detects that there is a lane change, the statistical value output means Initialize statistics.
(3) The vehicle meandering operation detecting device according to (1),
The lane change detection means distinguishes between a first white line displayed at a boundary position of a plurality of lanes on a road and a second white line displayed at a limit position near the road side end. Detecting lane change only when the vehicle moves across the first line.
(4) The vehicle meandering operation detecting device according to (3),
A blinker signal monitoring means for monitoring a state of a blinker signal representing a signal of a lane change by a driver's operation,
The statistical value initialization means is a case where the blinker signal does not appear, and when the lane change detection means detects a state in which the vehicle moves across the first line, the statistical value output means Initialize statistics,
The abnormality detection means detects an abnormality related to lane departure when the lane change detection means detects a state in which the vehicle moves across the second line when the blinker signal does not appear.
(5) The vehicle meandering operation detecting device according to (1),
The lateral position detecting means is
At least one imaging means that is mounted on the vehicle and outputs an image obtained by periodically photographing a subject in front of or behind the moving direction of the vehicle;
White line recognition means for recognizing display of white lines displayed on a road in the image based on a plurality of time-series images output from the imaging means;
FOE point determination means for determining an FOE point corresponding to an infinite point in the image based on the white line recognized by the white line recognition means;
An optical flow detecting means for detecting an optical flow representing a movement state of the same point in the image based on the FOE point;
Be provided.

According to the vehicle meandering operation detection device having the configuration (1), it is possible to prevent the occurrence of erroneous detection, and even if the meandering is abnormal, even a relatively small meander can be detected. That is, when the driver intentionally changes the lane, the statistical value initialization means initializes the statistical value, so that the change in the vehicle position accompanying the lane change is excluded from the statistical value. Therefore, intentional lane change and abnormal driving can be clearly distinguished, and even a small meander can be quickly detected as abnormal.
According to the vehicle meandering driving detection apparatus having the configuration (2), the intentional lane change is distinguished from the abnormal driving based on the presence / absence of the turn signal, and in the case of the intentional lane change, the statistical value is used. It can be initialized.
According to the vehicle meandering operation detection device having the configuration (3), the type of the detected white line or the like is distinguished, so that the situation where the vehicle straddles a plurality of lanes and the abnormal situation are simply identified. Can do. For example, if the line type is a dotted line or a broken line, it is assumed that the line is regarded as the first line displayed at the boundary of a plurality of lanes, and if the line type is a solid line, it is assumed that the line is regarded as the second line.
According to the vehicle meandering detection device having the configuration (4), the statistical value can be initialized even when the driver intentionally changes the lane without giving a signal of the winker, so that the meander detection is performed. Can prevent false detection. Further, in a situation where the vehicle deviates from the lane, the statistical value is not initialized, and an abnormality relating to lane departure is detected.
According to the meandering operation detecting device for a vehicle having the configuration of (5) above, since necessary information is collected based on a change in an image obtained by photographing on the vehicle, it is necessary to install special equipment on the road side. Absent.

  According to the present invention, occurrence of erroneous detection can be prevented, and even if the meandering is abnormal, even a relatively small meander can be detected as meandering. That is, when the driver intentionally changes the lane, the statistical value initialization means initializes the statistical value, so that the change in the vehicle position accompanying the lane change is excluded from the statistical value. Therefore, intentional lane change and abnormal driving can be clearly distinguished, and even a small meander can be quickly detected as abnormal.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a block diagram showing the main functional components regarding the meandering operation detection apparatus for vehicles of an embodiment. It is a block diagram showing the structure of the hardware of the meandering operation detection apparatus for vehicles shown in FIG. It is a flowchart which shows a part of operation | movement of the meandering operation detection apparatus for vehicles shown in FIG. It is a flowchart which shows a part of operation | movement of the meandering operation detection apparatus for vehicles shown in FIG. It is a front view which shows the example of the image obtained by imaging | photography with a vehicle-mounted camera. It is a front view which shows the example of the partial image obtained by differentiating the image | photographed image. It is a schematic diagram showing the relationship between an image and the operation | movement for detecting a white line. It is a schematic diagram showing the operation | movement for detecting an optical flow from an image. It is a schematic diagram showing the operation | movement for detecting the horizontal direction travel position of the own vehicle in the own lane. It is a top view showing the movement locus of the vehicle position on the road in the case of meandering driving.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An example of the hardware configuration relating to the vehicle meandering operation detection apparatus of the embodiment is shown in FIG. As shown in FIG. 2, the vehicular meandering detection device includes a camera 1 that is an imaging unit. The camera 1 is fixed in a predetermined posture at a position where a rear side subject (road surface or the like) can be imaged on the vehicle. Further, the camera 1 forms a two-dimensional image in the range of angle of view defined by the lens 1a on the image plane 1b. This image is converted into an electrical signal for each frame of the image taken by a conversion unit such as a two-dimensional CCD image sensor provided at the location of the image plane 1b, and further converted into image data that is a set of data for each pixel. .

  The storage unit 2 includes first and second frame memories 2a and 2b, a differential image memory 2c, and a divergent optical flow memory 2d. The first frame memory 2a and the second frame memory 2b convert the captured image data D1 imaged on the image plane 1b of the camera 1 into pixels of m rows and n columns such as 512 × 512 pixels and luminance 0 to 255 gradations. The converted data is temporarily stored as pixel data D2 and D3 and output to the microcomputer 3 (hereinafter referred to as the microcomputer 3). These first or second frame memories 2a and 2b, for example, capture images taken at a predetermined time Δt, such as time t for the first frame memory 2a, time t + Δt for the second frame memory 2b, and so on. Pixel data D2 and D3 converted into pixels of m rows and n columns are sequentially stored.

  The differential image memory 2c stores differential image data D4 generated by differentiating the captured image data D1 formed on the image plane 1b of the camera 1. The divergent optical flow memory 2d stores the optical flow data D5 in the diverging direction and outputs it to the microcomputer 3.

The microcomputer 3 includes a CPU (microprocessor) 3a that operates according to the control program, a ROM 3b that stores the control program of the CPU 3a and preset values, and a RAM 3c that temporarily stores data required when the CPU 3a performs operations. And have.
A blinker detection unit (blinker signal monitoring means) 4 is attached to the blinker mechanism of the vehicle, and when the blinker switch operated when the driver turns the vehicle to the left or right side is turned on, the blinker signal S1 of H level is output to the microcomputer 3 Output for.

  The alarm generation unit 5 serving as a lane departure warning unit and a meandering driving warning unit includes a speaker 5a and a display unit 5b. The alarm generation unit 5 displays an image captured by the camera 1, or detects a meandering operation and a lane departure, or determines that there is a risk of contact when another vehicle suddenly approaches the host vehicle. In addition, each message is displayed to inform the driver of the danger by video.

  The speaker 5a is a voice guidance or alarm sound based on the audio signal S2 emitted from the microcomputer 3 when a meandering operation and lane departure are detected, or when it is determined that there is a risk of contact with another vehicle. Is generated. The speaker 5a informs the driver of the danger by using this voice.

  The main functional configuration of the vehicle meandering operation detection apparatus shown in FIG. 2 is shown in FIG. The white line detection means 3a-1, FOE setting means 3a-2, optical flow detection means 3a-3, danger judgment means 3a-4, position detection means 3a-5, lane departure detection means 3a-6 shown in FIG. The meandering operation detection means 3a-7, the statistical value output means 3a-11, the statistical value initialization means 3a-12, and the lane change detection means 3a-13 are realized by the processing of the CPU 3a described above.

  The white line detection means 3a-1 detects a pair of white lines (road surface display) located on both sides of the own lane on which the host vehicle should travel. The FOE setting means 3a-2 identifies the aforementioned FOE point. The optical flow detection means 3a-3 detects the movement amount of the same point in two images obtained before and after a predetermined time from the camera using FOE as an optical flow. The danger determination means 3a-4 determines the danger by detecting the other vehicle approaching the host vehicle based on the magnitude of the optical flow of the other vehicle.

  Further, the position detection means 3a-5 detects the lateral position of the host vehicle in the host lane. The lane departure detection means 3a-6 detects lane departure traveling based on the lateral position of the host vehicle in the own lane. The meandering operation detection means 3a-7 detects the meandering operation based on a change in the lateral position of the host vehicle in the own lane with time (statistical value output by the statistical value output means 3a-11). The lane departure detection unit 3a-6 and the meandering operation detection unit 3a-7 may be collectively referred to as an abnormality detection unit 3a-10.

  The statistical value output means 3a-11 holds and outputs statistical value information relating to the lateral position necessary for detecting the meandering operation. As specific examples of the statistical values, for example, the position detection means 3a-5 sequentially calculates and outputs the lateral position information output within a predetermined time in the past as it is arranged in time-series order, or averaged every predetermined time. It is assumed that a predetermined number of information on the positions is arranged in chronological order.

  The statistical value initialization unit 3a-12 initializes the statistical value of the statistical value output unit 3a-11 when a predetermined condition is satisfied, and invalidates the statistical value held so far. In order to identify whether or not the condition for initializing the statistical value is satisfied, the statistical value initializing means 3a-12 refers to the detection state of the lane change detecting means 3a-13.

  The lane change detection means 3a-13 performs detection related to lane change and the like. Specifically, it is detected whether or not the host vehicle has moved to a position across the white line at both ends of the own lane on the road surface, and the type of the white line (solid line / dotted line) is identified. In other words, when the driver moves from one of the two adjacent lanes to the other (lane change), or when the host vehicle moves to a position that deviates from the lane regardless of the driver's intention. The lane change detection means 3a-13 detects an abnormal situation.

  A more detailed operation of the above-described vehicle meandering operation detection apparatus will be described below. First, the camera 1 outputs, for example, a captured image as illustrated in FIG. 5 to the microcomputer 3 as captured image data D1. This captured image is an image in which the road 10, the white lines 11 to 15 drawn on the road 10, and the wall 16 standing on both sides of the road 10 disappear at the horizontal center position on the screen. .

  As described above, the captured image shown in FIG. 5 corresponds to the left side of the captured image based on the traveling direction, since the camera 1 is attached to the rear of the vehicle toward the rear. The left side of corresponds to the right side when the traveling direction is used as a reference.

  The CPU 3a converts the captured image data D1 output from the camera 1 into the pixel data D2 having the above-mentioned 512 × 512 pixels and the luminance of 0 to 255 gradations, and outputs it to the first frame memory 2a. The first frame memory 2a temporarily stores the pixel data D2 so that the microcomputer 3 can always read it. Further, after time Δt, the microcomputer 3 outputs pixel data D3 of a captured image captured at time t + Δt to the second frame memory 2b. That is, the first and second frame memories 2a and 2b sequentially store pixel data D2 and D3 of images taken every predetermined time Δt.

Further, the CPU 3a scans the luminance values I _m and _n of the pixels in m rows and n columns in the horizontal direction in FIG. 5 with respect to the pixel data D2 of the captured image shown in FIG. 5 in order to detect lane departure or meandering operation. When the difference I _m , _{n + 1} −I _m , _n is equal to or greater than a predetermined luminance value when the difference between the luminance values I _m , _{n + 1} of the adjacent pixels is set, the luminance value I _m , _n = 1 is set, , Luminance value I _m , _n = 0, a differential image (edge image) that is an image of only the edge portion on the captured image as shown in FIG. 6 is generated, and the generated differential image is used as differential image data D4 to generate a differential image Output to the memory 2c.

Next, a reference line V _SL as shown in FIG. 7 is set for this differential image. The reference line V _SL is set so as to cut the differential image vertically in the vertical direction, which is the center position in the horizontal direction on the differential image. That is, the reference line V _SL is set at the center in the horizontal direction of the lane divided by the white lines 12 and 13 on which the host vehicle is traveling.

When the reference line V _SL is set, the search for edge points constituting the pair of white lines 12 and 13 located on both sides of the own lane on the road surface on which the own vehicle should travel is performed. The search for edge points constituting the white lines 12 and 13 is performed upward from the horizontal line H _(LO) located at the lower end of the screen shown in FIG. That is, the reference line V _SL on the A and the lowermost point P _(SO), to search for a edge point toward the horizontal direction at both ends. By this search, point constituting the edge of the white line 13 that is present on the right side of the reference line V _SL left P _(LO) and the reference line V _SL points constituting the edge of the white line 12 in the presence of P _(RO) is To be acquired.

Subsequently, the P _(S1) point located second from the lowermost end, the search for an edge point is performed toward the horizontal direction both end portions, thereby the edge of the white line 12 present on the left side of the reference line V _SL configuration It points P _(L1) and the reference line V _SL P points constituting the edge of the white line 13 that is present on the right side of _(R1) is obtained.

Edge points are sequentially extracted by performing such processing upward in the differential image. At this time, the edge points P _{(L (m + 2))} , P _{(R (m + 2))} , P _{(L (m + 4)),} and P _{(R (m + 4))} constituting the other vehicles traveling on the following side. _{Since 4)) is} also extracted, only those on the same straight line are extracted from the extracted edge points. As a result, it is possible to extract only the edge points constituting the pair of white lines 12 and 13 located on both sides of the own lane on the road surface on which the own vehicle is to travel. Then, an approximate line by the least square method is generated from the extracted edge points, and the approximate lines are detected as white lines 12 and 13. Then, the approximate lines detected as the white lines 12 and 13 are extended, and the intersection is set as the FOE. Further, with respect to the pixel data D3 of the captured image after time Δt, a pair of white lines 12 and 13 located on both sides of the own lane on the road surface on which the own vehicle should travel are detected, and the detected white lines 12 and 13 are extended. Set FOE at the point where the lines meet.

  Further, the CPU 3a obtains an optical flow for detecting the degree of danger with respect to another vehicle traveling in the adjacent lane or the following other vehicle. Hereinafter, the procedure for obtaining the optical flow will be described with reference to FIG. First, the pixel data D2 is fetched from the first frame memory 2a, and in the captured image at time t, with respect to one point of interest, the direction of radiation from the FOE set as described above with the one point of interest as the center ( That is, an elongated window is set in the direction connecting the FOE and one point of interest (FIG. 8A). Next, the pixel data D3 is fetched from the second frame memory 2b, and in the captured image at time t + Δt, the window is moved point by point in a radial direction from the FOE, and each pixel constituting the window at time t The absolute value of the luminance difference with each pixel constituting the window at time t + Δt corresponding to the pixel is obtained. That is, the absolute value of the luminance difference from the pixel Q (FIG. 8B) at the time t + Δt corresponding to the pixel P at the time t (FIG. 8A) is obtained. The amount of movement of the window when the sum of the obtained luminance differences is minimized is obtained as an optical flow of one point of interest.

  The optical flow of the entire captured image can be obtained by repeating the above processing at all points of the captured image. Alternatively, the pixels in the window may be scanned to extract points of interest, and the optical flow may be obtained by connecting the extracted points.

  If the direction of the obtained optical flow is the direction toward FOE, it indicates that the other vehicle traveling in the neighboring lane or the other vehicle traveling in the succeeding lane is slower than the speed of the own vehicle and away from the own vehicle. When the direction of the flow is a direction that diverges with respect to the FOE, it indicates that the vehicle is approaching.

  In addition, the direction of the optical flow generated by the scenery in the captured image, the mark on the road surface, and the like is all directed toward the FOE, and can be easily distinguished from the neighboring nearby or subsequent vehicles. The length of the optical flow emitted from the neighboring or succeeding other vehicle is proportional to the relative speed between the own vehicle and the neighboring or succeeding other vehicle. Accordingly, when the length of the optical flow in the direction of divergence from the FOE exceeds a predetermined length, it is assumed that the other vehicle is approaching the host vehicle. “There is a car to come”, and the display unit 5b displays “approach to another vehicle”.

  Further, the CPU 3a sets a vertical line L from the FOE as a reference line as shown in FIG. 9 in order to detect the lateral position of the own vehicle in the own lane, and the vertical line L and the white lines 12 and 13 are formed. The angles θ1 and θ2 are detected, and the angle difference θ1-θ2 between the angles θ1 and θ2 is obtained. Next, similarly for the pixel data D3 of the captured image after Δt, the angle difference θ1-θ2 is obtained. That is, the angle difference θ1-θ2 is obtained for each Δt.

  As a result of obtaining the angle difference θ1-θ2, if the vehicle is traveling in the center of the lane as shown in FIG. 9, the angle difference θ1-θ2 = 0 (FIG. 9A). Also, if the host vehicle is traveling to the left as viewed from the camera 1 in the host vehicle, the angle difference θ1−θ2 <0 (FIG. 9B), and the angle difference θ1 as the host vehicle is closer to the left side of the host vehicle lane. The value of -θ2 becomes small. Further, if the host vehicle is traveling to the right when viewing the lane from the camera 1, the angle difference θ1−θ2> 0 (FIG. 9C), and the angle difference θ1−θ2 increases as the right side of the lane. The value gets bigger. As described above, by obtaining the angle difference θ1-θ2, the lateral position of the host vehicle can be detected in the host lane every time Δt. Such operation is performed by the position detection means 3a-5.

  In addition to the above-described method, various modifications can be considered for the method of detecting the lateral position. These modified examples are also disclosed in Patent Document 1, for example.

  The lane departure detection means 3a-6 automatically detects the lane departure traveling of the host vehicle based on the lateral position detected by the position detection means 3a-5. Specifically, the angle difference θ1-θ2 obtained from the image captured when the host vehicle deviates to the left side when viewed from the camera 1 in the own lane is a first predetermined value, and the image is imaged when the vehicle deviates to the right side. The lane departure traveling is detected when the angle difference θ1-θ2 obtained from the above is the second predetermined value and the angle difference θ1-θ2 is not less than the first predetermined value or not more than the second predetermined value. However, if the driver deliberately changes lanes or is not dangerous, it is not regarded as lane departure. Details will be described later.

  When the lane departure detecting means 3a-6 detects lane departure traveling, for example, the speaker 5a is audibly alerted "lane departure driving" from the speaker 5a, and "lane departure" is displayed on the display unit 5b. Is used to warn of lane departure due to falling asleep. For this reason, it is possible to prevent an accident due to falling asleep.

  The meandering operation detection means 3a-7 detects the meandering operation based on the statistical value of the lateral position output from the statistical value output means 3a-11. In the meandering operation, for example, the vehicle moves while wobbling in the lateral direction along a movement locus like a curve shown in FIG.

  For example, the lateral positions detected from the images taken at every Δt are representative points of the past movement trajectory of the vehicle such as the points P1, P2, P3, P4, P5, P6, P7, and P8 shown in FIG. It becomes position information showing. The position information regarding such a plurality (predetermined number) of points is output as a statistical value from the statistical value output means 3a-11.

  In the example shown in FIG. 10, points N1 (P3), N2 (P6)... That are locus peaks are extracted from the statistical values, and the displacement amount ΔM of the lateral position between adjacent extracted points is calculated. When the threshold value (th1) is exceeded for a predetermined number of times (th3) within a predetermined time (th2), the meandering operation detecting means 3a-7 detects the meandering operation. Then, in order to notify that effect, the speaker 5a gives an alarm that “meandering is in operation” and causes the display unit 5b to display “meandering operation”. . For this reason, it is possible to prevent an accident due to falling asleep. Furthermore, the meandering operation due to falling asleep can be detected at low cost by using it for detecting the lane departure due to falling asleep from the lateral position of the vehicle detected as described above.

  However, depending on the situation, the meandering operation detecting means 3a-7 may not be able to detect the meandering operation correctly. For example, the driver may intentionally change the lane when one of a plurality of lanes can be selectively driven as when driving on an expressway. In that case, since the change in the lateral position detected by the position detection means 3a-5 becomes large, if this position information is included in the statistical value of the statistical value output means 3a-11, the meandering operation detection means 3a-7 will not fluctuate. There is a possibility that a meandering operation is erroneously detected as a large state.

  In order to prevent such erroneous detection of the meandering operation detecting means 3a-7, when the lane change detecting means 3a-13 detects a lane change, the statistical value initializing means 3a-12 is output by the statistical value output means 3a. Initialize -11 statistics. By this initialization, large fluctuations in the lateral position caused by the lane change are excluded from the statistical values. Therefore, even if the thresholds th1, th2, and th3 do not have a large margin, erroneous detection of the meandering operation detection means 3a-7 is less likely to occur, detection sensitivity is increased, and detection delay is less likely to occur.

  Most of the operations described above are realized by the processing of the CPU 3a of the microcomputer 3. The procedure of this process is shown in FIGS. The processes shown in FIGS. 3 and 4 will be described below.

  First, captured image data D1 of a captured image at time t as shown in FIG. 5 is captured from the camera 1 and stored in the first frame memory 2a as pixel data D2 corresponding to the captured image data D1 at time t (step SP1). ). Next, each captured image data D1 at time t + Δt is captured and stored in the second frame memory 2b as pixel data D3 (step SP2). Differentiated images are generated by differentiating the pixel data D2 and D3 (step SP3), and white lines forming both sides of the own lane on which the vehicle travels are detected (step SP4). Next, the detected white lines on both sides are extended, and the intersection is set as FOE (step SP5).

  Next, an optical flow is detected in order to detect the danger to another vehicle traveling in the adjacent lane or the following vehicle (step SP6), and the calculated optical flow diverges from the FOE and has a predetermined length. When the vehicle exceeds the length, the other vehicle is approaching the host vehicle (Y in step SP7). In order to notify that, for example, the speaker 5a gives an alarm “There is a car approaching” and the display unit The other vehicle sudden approach is displayed on 5b (step SP8), and the process returns to step SP2. If there is no other vehicle approaching when the length of the optical flow converges on the FOE or the length of the optical flow does not exceed the predetermined length (N in step SP7), the process proceeds to the next step.

  Next, as shown in FIG. 9, the angles θ1 and θ2 formed by the perpendicular line L drawn from the FOE set on the pixel data D2 of the captured image at time t and the white lines 12 and 13 are detected, and the angles θ1 and θ2 are detected. To obtain an angle difference θ1-θ2. Next, similarly for the pixel data D3 of the captured image at time t + Δt, an angle difference θ1-θ2 is obtained (step SP9).

Steps SP20 to SP28 shown in FIG. 4 are processes relating to meandering operation, lane departure detection and warning.
In step SP20, it is identified whether or not the winker signal S1 is output from the winker detector 4. This is a process for grasping the possibility of the driver's intentional lane change. That is, if the turn signal S1 is output, there is a high possibility that the lane change is intentionally performed. However, since the driver may change the lane without giving a turn signal, there is a possibility of intentional lane change even if the turn signal S1 is not output.

  When the turn signal S1 is not output, the process proceeds from step SP20 to SP21, and detection relating to lane change or lane departure is performed. In step SP21, the latest lateral position output from the position detection means 3a-5 is monitored, and it is identified whether or not the vehicle has moved to a position straddling the lane side end. That is, it is identified whether or not the host vehicle has moved to a position that crosses one of the white lines at the left and right ends of the currently traveling lane. If it is within the own lane, the process proceeds to step SP25, and if it has moved to a position crossing the white line, the process proceeds to step S22.

  In step SP22, in order to distinguish lane departure from lane change, the type of white line that the host vehicle straddles is identified. For example, when there are two lanes as the lane in which the vehicle can travel as in the example shown in FIG. 5, the white line 12 at the boundary of the plurality of lanes is displayed on the road surface as a dotted line, and is near the limit position at the left end of the road. The white line 11 and the white line 13 representing the center line are displayed on the road surface as solid lines.

  That is, in the state shown in FIG. 5, if the vehicle moves within the range of the adjacent lane across the dotted white line 12, it can be regarded as a lane change, but the solid white line 11 or the white line 13 is crossed. If this happens, it must be considered a dangerous situation, that is, a lane departure. Therefore, if the type of white line straddled in step SP22 is a dotted line, it is regarded as “lane change” and the process proceeds to step SP23, and if the type of white line is a solid line, it is regarded as “lane departure”. Proceed to SP24.

  In step S23, after confirming that the host vehicle completes the lane change, the statistical value of the horizontal position held by the statistical value output means 3a-11 is initialized (the past value held is stored). clear). To confirm the completion of the lane change, identify whether the vehicle has moved into the new lane and then moved near the center of the lane, or whether the change in position has become smaller. Is assumed.

  In step SP24, since the vehicle is in the “lane departure” state, in order to notify the driver of this, for example, the speaker 5a gives a warning “Vehicle has deviated” from the speaker 5a, and displays the lane departure on the display unit 5b.

  On the other hand, when the winker signal S1 is output, since it is highly likely that the lane change is made by the driver's will, it is identified whether or not the lane change is detected in step SP27. Specifically, the lateral position output by the position detection means 3a-5 is monitored, and “lane change” is detected when moving to a position straddling any one of the white lines. If "lane change" is detected, the process proceeds to step SP28, and if no lane change is detected even after a predetermined time has elapsed, the process proceeds from step SP27 to SP25. In step SP27, it is not necessary to identify the type of white line.

  In step SP28, after confirming that the host vehicle completes the lane change, the statistical value of the horizontal position held by the statistical value output means 3a-11 is initialized (the past value held is stored). clear).

  In step SP25, a wobble evaluation value is calculated based on the statistical value of the lateral position output from the statistical value output means 3a-11, and the presence or absence of meandering operation is identified according to the result. That is, since the statistical value output from the statistical value output means 3a-11 is information such as the horizontal direction of each point P1 to P8 shown in FIG. 10, based on this, each point N1 that becomes a peak of the locus (P3), N2 (P6)... Are extracted, and the displacement amount ΔM of the lateral position between adjacent extracted points is calculated as a fluctuation evaluation value, and this displacement amount ΔM exceeds the threshold value (th1). Is detected during a predetermined number of times (th3) within a predetermined time (th2). When “meandering operation” is detected, the process proceeds to step SP26, and in order to notify that, for example, the speaker 5a is audibly alerted “meandering operation” and the display unit 5b is displayed.

  In any case, when the vehicle changes lanes according to the driver's will, this is automatically detected, and the statistical value of the statistical value output means 3a-11 is initialized at step SP23 or SP28. Therefore, when the meandering operation detection means 3a-7 evaluates the wobbling in step SP25, the evaluation is performed based only on the statistical value not including the influence of the lane change. Accordingly, it is possible to prevent the “meandering operation” alarm from being erroneously output due to the influence of the lane change even when the meandering operation is not performed. Further, since it is difficult for erroneous detection to occur, it is not necessary to provide a large margin for the threshold values (th1, th2, th3) used for evaluating the wobbling, the detection sensitivity of meandering operation is increased, and detection delay is less likely to occur.

  As described above, by mounting the vehicle meandering driving detection device of the present invention in an automobile, it is possible to automatically issue alarms regarding meandering driving and lane departure, and avoid dangerous situations such as driver's carelessness and dozing. To help. In particular, even in the case where one of a plurality of lanes can be selectively traveled like an expressway, meandering operation can be detected with high accuracy without erroneous detection.

1 Imaging means (camera)
2 Memory 3 Microcomputer 3a-1 White line detection means 3a-2 FOE setting means 3a-3 Optical flow detection means 3a-4 Risk judgment means 3a-5 Position detection means 3a-6 Lane departure detection means 3a-7 Meandering operation detection Means 3a-10 Abnormality detection means 3a-11 Statistical value output means 3a-12 Statistical value initialization means 3a-13 Lane change detection means 4 Winker detection section 5 Alarm generation section

Claims (5)

A lateral position detecting means for recognizing a lane of a road on which the vehicle travels and detecting a lateral positional relationship between the lane and the vehicle; an abnormality in meandering operation based on a change in the positional relationship; A vehicle meandering operation detection device comprising an abnormality detection means for identifying the presence or absence of
Statistical value output means for obtaining and outputting a statistical value according to a time-series change related to the horizontal position detected by the horizontal position detection means;
Lane change detection means for detecting the presence or absence of a lane change indicating that the vehicle has moved across a plurality of adjacent lanes;
A statistical value initializing means for initializing a statistical value of the statistical value output means when the lane change detecting means detects that there is a lane change;
The vehicle meandering operation detecting device, wherein the abnormality detecting means identifies presence / absence of an abnormality in meandering operation based on the latest statistical value output from the statistical value output means. A blinker signal monitoring means for monitoring a state of a blinker signal representing a signal of a lane change by a driver's operation,
The statistical value initialization means, when the blinker signal appears, when the lane change detection means detects that there is a lane change, the statistical value output means The meandering operation detection device for a vehicle according to claim 1, wherein the statistical value is initialized.   The lane change detection means distinguishes between a first white line displayed at a boundary position of a plurality of lanes on a road and a second white line displayed at a limit position near the road side end. The vehicle meandering operation detecting device according to claim 1, wherein the vehicle lane change is detected only when the vehicle moves across the first line. A blinker signal monitoring means for monitoring a state of a blinker signal representing a signal of a lane change by a driver's operation,
The statistical value initialization means is a case where the blinker signal does not appear, and when the lane change detection means detects a state in which the vehicle moves across the first line, the statistical value output means Initialize statistics,
The abnormality detection means detects an abnormality related to lane departure when the lane change detection means detects a state in which the vehicle moves across the second line when the blinker signal does not appear. The meandering operation detection device for a vehicle according to claim 3. The lateral position detecting means is
At least one imaging means that is mounted on the vehicle and outputs an image obtained by periodically photographing a subject in front of or behind the moving direction of the vehicle;
White line recognition means for recognizing display of white lines displayed on a road in the image based on a plurality of time-series images output from the imaging means;
FOE point determination means for determining an FOE point corresponding to an infinite point in the image based on the white line recognized by the white line recognition means;
An optical flow detecting means for detecting an optical flow representing a movement state of the same point in the image based on the FOE point;
The vehicle meandering operation detection device according to claim 1, comprising:

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