JP2015215746A - Approaching vehicle detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect other vehicle in an adjacent traffic lane without being affected by other vehicle in a traffic lane at two adjacent traffic lanes from a current traffic lane.SOLUTION: A lane marker detection unit 80 is configured to detect at least lane markers L2 and L3 indicative of a boundary of an adjacent traffic lane 22 from an image I photographed by a rear camera 50 (imaging unit), and a window setting unit 84 is configured to set windows Ai and Bi(i=1, 2, ...) different in a distance from a vehicle 10 at a location crossing the lane markers L2 and L3, respectively. When an area determination unit 88 determines that a head light of other vehicle 14 travelling in a second traffic lane 24 adjacent to a distant side of the adjacent traffic lanes 22 when viewing from a vehicle 10 are reflected at a location crossing the lane L3 on a distant side from the vehicle 10 on the basis of luminance evaluation values EV(Ai) and EV(Bi) of the image I corresponding to each of windows Ai and Bi calculated by a luminance distribution calculation unit 85, an approaching vehicle detection unit 92 is configured to not detect other vehicle 12 travelling in the adjacent traffic lane 22 over a nullification time Tn (prescribed time).

Description

  The present invention is installed in a vehicle and detects the presence of an approaching vehicle traveling in an adjacent lane on the deviating side when there is a possibility of deviating from the lane when changing lanes, etc. The present invention relates to a vehicle detection device.

  In recent years, a rear side monitoring device (BSW (Blind Spot) that installs a camera on a vehicle and detects an approaching vehicle from an image obtained by imaging the rear side of the vehicle that becomes a blind spot with respect to the driver and alerts the vehicle. Warning)) technology has been proposed.

  For example, in the rear side vehicle alarm device described in Patent Document 1, a moving object present in an adjacent lane adjacent to a traveling lane in which the vehicle is traveling, and a lane marker far from the vehicle in the adjacent lane , And the other vehicle traveling in the adjacent lane is detected based on these detection results.

Japanese Patent Laid-Open No. 9-240397

  In such a conventional rear side vehicle alarm device, for example, at night, if the light of the headlamps of other vehicles traveling in two adjacent lanes is reflected on the road surface, it is as if the adjacent lanes An image is captured as if another vehicle is present. For this reason, there is a risk of erroneous detection that there is another vehicle traveling in the adjacent lane.

  The present invention has been made in view of the above-described problem, and erroneously travels in an adjacent lane adjacent to a travel lane in another vehicle traveling in a lane next to the travel lane in which the vehicle is traveling. It is an object of the present invention to provide an approaching vehicle detection device that is not detected as another vehicle.

  In the approaching vehicle detection device according to the present invention, at night, an approaching vehicle (another vehicle) traveling in an adjacent lane with the headlights lit, two adjacent vehicles with the headlights lit. It is reliably detected without making a mistake with other vehicles traveling in the lane.

  That is, the approaching vehicle detection device according to the present invention applies a headlamp on an adjacent lane of the traveling lane, which is applied to a vehicle traveling on a road lane having three or more lanes on one side. An approaching vehicle detection device that detects another vehicle approaching from behind the vehicle in a state, an imaging unit that captures an image including a road behind the vehicle, and at least left and right of the adjacent lane from the image A lane marker detection unit for detecting each lane marker indicating the boundary of the vehicle, and a window for setting a window crossing each lane marker detected by the lane marker detection unit at a plurality of positions having different distances from the vehicle in the image. A luminance distribution calculation unit for calculating a luminance evaluation value based on a luminance distribution of a region corresponding to each window in the image; Based on the degree evaluation value, among the lane markers indicating the left and right boundaries of the adjacent lane, the headlights of other vehicles traveling in the adjacent lane are reflected at a position crossing the far lane marker as viewed from the vehicle. An area determination unit that determines whether or not the headlights of other vehicles traveling in two adjacent lanes adjacent to the far side of the adjacent lane as viewed from the vehicle are reflected, and the rear of the vehicle An approaching vehicle detection unit that detects another vehicle on the adjacent lane approaching from the vehicle, and the area determination unit is far from the vehicle among lane markers that indicate left and right boundaries of the adjacent lane. When it is determined that a headlight of another vehicle traveling in the two adjacent lanes is reflected at a position crossing the lane marker on the side, the approaching vehicle detection unit Detect other vehicles And characterized by the absence.

  According to the approaching vehicle detection device according to the present invention configured as described above, the lane marker is selected from the images behind the vehicle captured by the imaging unit while traveling on a road lane having three or more lanes on one side. A window that crosses each lane marker detected by the lane marker detection unit at a plurality of positions at different distances from the vehicle at a position of a lane marker that indicates at least the left and right boundaries of the adjacent lane of the vehicle detected by the detection unit And the luminance distribution calculation unit calculates a luminance evaluation value based on the luminance distribution of the region corresponding to each window in the image, and the region determination unit calculates the adjacent lane based on the luminance evaluation value. Is the headlamp of another vehicle traveling in the adjacent lane reflected at a position that crosses the lane marker on the far side as seen from the vehicle among the lane markers that indicate the left and right boundaries Or, it is determined whether the headlights of other vehicles traveling in the two adjacent lanes adjacent to the far side of the adjacent lane as viewed from the vehicle are reflected, and other vehicles traveling in the two adjacent lanes When it is determined that the headlamps are reflected, the approaching vehicle detection unit does not detect other vehicles traveling in the adjacent lane for a predetermined time. The other vehicle traveling in the lane is not erroneously determined as the other vehicle traveling in the adjacent lane with the headlamp turned on. This makes it possible to reliably detect an approaching vehicle (another vehicle) traveling in the adjacent lane.

It is a 1st figure explaining the road environment to which the approaching vehicle detection apparatus which concerns on this invention is applied. It is a 2nd figure explaining the road environment to which the approaching vehicle detection apparatus which concerns on this invention is applied. 1 is a system configuration diagram showing a hardware configuration of a lane departure and rear side monitoring apparatus according to Example 1 which is an embodiment of the present invention. It is a functional block diagram which shows the function structure of the lane departure and rear side monitoring apparatus which concerns on Example 1 which is 1 embodiment of this invention. It is a figure explaining the outline | summary of the lane marker detection process in Example 1, (a) is the example which set the brightness | luminance evaluation area | region for detecting a lane marker on the imaged image. (B) is a figure explaining a mode that the brightness distribution inside the set brightness | luminance evaluation area | region is calculated in order to pinpoint the position of a lane marker. (C) is a figure which shows the state which pinpointed the position of the lane marker. It is a figure explaining the outline | summary of an area | region determination process (the presence / absence determination process of the vehicle of two adjacent lanes), (a) is the time of the brightness | luminance evaluation value when the vehicle which turned on the headlamp exists in the adjacent lane It is a figure which shows an example of transition. (B) is a figure which shows an example of the time transition of a brightness | luminance evaluation value when the vehicle which turned on the headlamp exists in two adjacent lanes. (C) is a figure which shows an example of the time transition of a brightness | luminance difference when FIG. 5 (a), (b) is obtained. It is a figure explaining the function of the approaching vehicle detection part in Example 1. FIG. 3 is a flowchart illustrating an overall flow of processing executed in the first embodiment. It is a flowchart which shows the flow of the process which judges the presence or absence of the vehicle of two adjacent lanes performed in the flowchart of FIG. It is a flowchart which shows the flow of the vehicle detection invalidation process of an adjacent lane performed in the flowchart of FIG. It is a functional block diagram which shows schematic structure of the lane departure and rear side monitoring apparatus which concerns on Example 2 which is 1 embodiment of this invention. It is a figure explaining the outline | summary of the area | region determination process (the presence / absence determination process of the vehicle of two adjacent lanes) performed in Example 2. FIG. 10 is a flowchart illustrating a flow of processing for determining whether there is a vehicle in two adjacent lanes, which is executed in the second embodiment.

  Hereinafter, specific embodiments of the approaching vehicle detection device according to the present invention will be described with reference to the drawings.

In the first embodiment, the present invention monitors the road on the rear side of the traveling vehicle, and the driver changes the lane when there is an approaching vehicle in a predetermined distance range on the rear side of the adjacent lane. When an intention is indicated, or when the driver does not intend to change lanes, there is a possibility that the vehicle may deviate from the lane, a warning is issued and a warning is issued. This is applied to a lane departure and rear side monitoring device that displays an image of the rear of the vehicle and assists the driver in reverse operation. The warning function for approaching vehicles is hereinafter referred to as a BSW function. The warning function for lane departure is called an LDW (Lane Departure Warning) function.
(Explanation of system configuration of lane departure and rear side monitoring device)

  First, an outline of the lane departure and rear side monitoring device 100a and a road environment to which the lane departure and rear side monitoring device 100a is applied will be described with reference to FIGS. 1A and 1B. This lane departure and rear side monitoring device 100a operates while traveling on a road having the number of lanes of three or more lanes on one side. Although the lane departure and rear side monitoring device 100a operates regardless of day or night, in particular, by applying the present invention, it operates more effectively at night.

  FIG. 1A is a diagram illustrating an example of a road 30 to which the lane departure and rear side monitoring device 100a is applied. The road 30 includes a traveling lane 20 on which the vehicle 10 on which the lane departure and rear side monitoring device 100a is mounted is traveling, an adjacent lane 22 adjacent to the right of the traveling lane 20, and a further right of the adjacent lane 22. It consists of three lanes, two adjacent lanes 24 adjacent to each other. The left and right ends of the traveling lane 20 are divided by lane markers L1 and L2, respectively, the left and right ends of the adjacent lane 22 are respectively divided by lane markers L2 and L3, and the left and right ends of the two adjacent lanes 24 are respectively lane markers L3 and L3. It is partitioned by L4.

  Now, the vehicle 10 is traveling on the road lane 20 of the road 30 in the left direction of the drawing (in the direction of the arrow 10d). The rear camera 50 installed rearward at the rear end of the vehicle 10 captures an imaging range ω including at least the traveling lane 20 and the adjacent lane 22. And the other vehicle 12 (progress in the direction of arrow 12d) which is in the predetermined distance range from the vehicle 10 on the adjacent lane 22 and is approaching the vehicle 10 is detected from the captured image. And when the other vehicle 12 approaching the vehicle 10 is detected, if the driver of the vehicle 10 tries to change the lane of the vehicle 10 to the adjacent lane 22 side, an alarm is issued and alerted as will be described later. Do.

  Further, the lane departure and rear side monitoring apparatus 100a detects the positions of the lane markers L1 and L2 at the left and right ends of the traveling lane 20 from the image captured by the rear camera 50, and the vehicle 10 detects the traveling lane 20 as a result. Determine whether there is a risk of departure. When it is determined that the vehicle 10 is likely to deviate from the traveling lane 20, a warning is output and alerted as will be described later.

  At this time, it is assumed that the other vehicle 12 lights up the irradiation range 12r by turning on the headlamps 12h and 12h. Further, it is assumed that the other vehicle 14 traveling in the direction of the arrow 14d in the two adjacent lanes 24 lights the headlamps 14h and 14h to illuminate the irradiation range 14r.

  FIG. 1A illustrates only the right rear side region of the vehicle 10, but the lane departure and rear side monitoring device 100 a similarly acts on the left rear side region of the vehicle 10. . That is, as shown in FIG. 1B, when the vehicle 10 is traveling in the traveling lane 20, the rear camera 50 has the traveling lane 20 with the lane markers L 1 and L 2 at the left and right ends, and the lane markers L 5 and L 1 respectively in the left and right directions. The imaging range ω including the adjacent lane 26 as an end is imaged. Then, the other vehicle 16 (progressing in the direction of the arrow 16d) approaching the vehicle 10 in the predetermined distance range on the rear lane 26 on the adjacent lane 26 from the captured image is approached. To detect. And when the other vehicle 16 approaching the vehicle 10 is detected, if the driver of the vehicle 10 tries to change the lane of the vehicle 10 to the adjacent lane 26 side, an alarm is issued and alerted as will be described later. Do.

  Further, the lane departure and rear side monitoring apparatus 100a detects the position of the lane markers L1 and L2 from the image captured by the rear camera 50, and whether or not the vehicle 10 may deviate from the traveling lane 20 is determined. Determine whether. When it is determined that the vehicle 10 is likely to deviate from the traveling lane 20, a warning is issued and alerted as will be described later.

  At this time, it is assumed that the other vehicle 16 lights the headlamps 16h and 16h to illuminate the irradiation range 16r. Further, the other vehicle 18 traveling in the direction of the arrow 18d along the two adjacent lanes 28 with the lane markers L6 and L5 at the left and right ends respectively illuminates the irradiation range 18r by turning on the headlamps 18h and 18h. It shall be.

  Next, the system configuration of the lane departure and rear side monitoring apparatus 100a will be described with reference to FIG. FIG. 2 is a system configuration diagram showing a hardware configuration of the lane departure and rear side monitoring apparatus 100a.

  The lane departure and rear side monitoring apparatus 100a is installed in the vehicle 10 and is installed rearward in the vicinity of the rear license plate of the vehicle 10 to monitor the rear side of the vehicle 10, and a rear camera. 50, a camera ECU (Electronic Control Unit) 52a that controls the imaging operation and processes the captured image, a vehicle speed sensor 54 that detects the vehicle speed of the vehicle 10 installed in the camera ECU 52a and the vehicle 10, and The camera ECU 52a is connected to a turn signal switch 56 that outputs the direction of the indicated turn signal in conjunction with a turn signal operation (turn signal lever) (not shown) operated by the driver. , A CAN (Controller Area Network) communication line 58 for monitoring the vehicle speed v of the vehicle 10 and the operating state of the winker, and lane departure monitoring Lane departure / rear side monitoring switch 60 for operating the function and the rear side monitoring function, a monitoring state indicator 62 for displaying the operating state of the lane departure monitoring function and the rear side monitoring function, a lane departure warning, and A buzzer 64 that outputs an approaching vehicle alarm and a left rear side approaching vehicle that is installed in the vicinity of the left door mirror in the passenger compartment of the vehicle 10 and that informs that there is an approaching vehicle on the left rear side of the vehicle 10. An indicator 66a, a right rear side approaching vehicle indicator 66b made of an LED or the like, which is installed near the right door mirror in the passenger compartment of the vehicle 10 and informs that there is an approaching vehicle on the right rear side of the vehicle 10, and a rear camera 50, a monitor 70 that displays the image captured at 50, a reverse switch 72 that detects that the shift position of the vehicle 10 has been set to the reverse position, and reverse Lights when the switch 72 is turned on, provided with a reverse lamp 74 provided at the rear end of the vehicle 10.

The rear camera 50 has an automatic gain control function that automatically adjusts the gain of the video signal according to the ambient brightness. The brightness gain value adjusted by the automatic gain control function is output together with the video signal.
(Explanation of functional configuration of lane departure and rear side monitoring device)

  Next, the functional configuration of the lane departure and rear side monitoring apparatus 100a will be described with reference to FIG. FIG. 3 is a functional block diagram showing a functional configuration of the lane departure and rear side monitoring apparatus 100a.

  As shown in FIG. 3, the lane departure and rear side monitoring device 100a includes the above-described rear camera 50, the above-described camera ECU 52a, and the above-described lane departure / rear side monitoring switch 60 mounted on the vehicle 10. The vehicle speed sensor 54 described above, the reverse switch 72 described above, the monitor 70 described above, the buzzer 64 described above, and an approaching vehicle indicator 66 indicating that another vehicle approaching the vehicle 10 is present in the adjacent lane. And consist of The approaching vehicle indicator 66 includes the left rear side approaching vehicle indicator 66a and the right rear side approaching vehicle indicator 66b described above.

  Here, the camera ECU 52a detects a lane marker (L1, L2, L3 in FIG. 1A or L1, L2, L5 in FIG. 1B) from the image I captured by the rear camera 50; Based on the brightness of the surrounding environment, the night determination unit 82 that determines whether it is night or not, and the lane markers detected by the lane marker detection unit 80 (L1, L2, L3 in FIG. 1A or L1, L in FIG. 1B) A window setting unit 84 for setting a plurality of windows with different distances from the vehicle 10 at positions crossing L2, L5), and a luminance distribution of an area of the image I corresponding to each window set by the window setting unit 84. Based on the luminance distribution calculation unit 85 that calculates the average luminance value as the luminance evaluation value EV, and the luminance inside each window calculated by the luminance distribution calculation unit 85 Based on the value EV, in the image I, two windows set at positions equidistant from the vehicle 10 at positions crossing the left and right lane markers L3, L2 (L5, L1) of the adjacent lane 22 (26). Based on the calculation result of the luminance difference calculation unit 86 and the luminance difference calculation unit 86 that calculates the difference value of the luminance evaluation value EV of each corresponding region, the adjacent lane 22 adjacent to the travel lane 20 in which the vehicle 10 is traveling. (26) The high brightness area is the front of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) adjacent to the far side of the adjacent lane 22 (26) when viewed from the vehicle 10. An area determination unit 88 that determines which of the area in which the light is reflected, or the area in which the headlamp of the other vehicle 12 (16) traveling in the adjacent lane 22 (26) is reflected; And drive in two adjacent lanes 24 (28) A moving speed difference calculating unit 90 for calculating the relative speed of the vehicle 14 (18), an approaching vehicle detecting unit 92 for detecting the other vehicle 12 (16) approaching the vehicle 10 on the adjacent lane 22 (26), and A lane departure determination unit 94 that determines whether or not the vehicle 10 may deviate from the travel lane 20. The detailed operation of each part will be described later.

Then, the lane marker detection unit 80, the night determination unit 82, the window setting unit 84, the luminance distribution calculation unit 85, the luminance difference calculation unit 86, the region determination unit 88, and the moving speed difference calculation unit 90 described above. The approaching vehicle detection unit 92 constitutes an approaching vehicle detection device 95a.
(Description of rear side monitoring function (BSW function) during forward travel)

  The rear side monitoring function when the vehicle 10 is traveling forward in the lane departure and rear side monitoring device 100a is activated when the vehicle 10 is traveling at a vehicle speed v (for example, 30 km / h or more) within a predetermined range. . It may be activated when the lane departure / rear side monitoring switch 60 described above is operated. When the rear side monitoring function is operating, the fact is displayed on the monitoring status indicator 62.

  When the other vehicle 12 approaching the vehicle 10 is detected within a predetermined distance range on the rear side of the vehicle 10 after the rear side monitoring function is activated, it is installed in the vicinity of the left and right door mirrors. By illuminating the side approaching vehicle indicator 66a or the right rear side approaching vehicle indicator 66b, the presence of the other vehicle 12 is transmitted to the driver by visual information, and a warning is given when changing lanes (1). Next alarm).

  Furthermore, if the driver is not aware of the primary warning and tries to change the lane by taking the turn signal to the adjacent lane side where the other vehicle 12 exists, the state of the turn signal switch 56 is detected, and the left rear side approach is detected. The vehicle indicator 66a or the right rear side approaching vehicle indicator 66b is blinked to output emphasized visual information, and further, the buzzer 64 is blown to make the presence of the other vehicle 12 clearer to the driver. Communicate and urge the lane change operation to be interrupted (secondary alarm).

The rear side monitoring function is canceled when the vehicle speed of the vehicle 10 falls below a predetermined value (for example, 20 km / h) or when the lane departure / rear side monitoring switch 60 described above is operated. .
(Explanation of rear side monitoring function (back monitor function) during reverse running)

In the lane departure and rear side monitoring device 100a, the rear side monitoring function when the vehicle 10 is traveling backward is the shift position when the shift position of the vehicle 10 is set to the reverse position and the reverse lamp 74 is lit. Is detected by the reverse switch 72, and the rear side image of the vehicle 10 imaged by the rear camera 50 is displayed on the monitor 70 to assist the vehicle 10 in the backward operation. Then, when the shift position of the vehicle 10 leaves the reverse position, this function stops operating. In addition, since this function is implemented in many vehicles as a rear view monitor system these days, detailed description is abbreviate | omitted.
(Explanation of lane departure monitoring function (LDW function))

  The lane departure and rear side monitoring function of the lane departure and rear side monitoring device 100a is activated when the lane departure / rear side monitoring switch 60 is operated, and the winker operation is not performed while the vehicle 10 is traveling forward. When there is a possibility of deviating from the left and right lane markers L1 and L2 (see FIGS. 1A and 1B) of the traveling lane 20, this is detected and a warning is given. The lane departure monitoring function may be automatically activated when the vehicle 10 is traveling at a vehicle speed v within a predetermined range (for example, 30 km / h or more). The lane departure monitoring function is canceled when the vehicle speed of the vehicle 10 falls below a predetermined value (for example, 20 km / h). When the lane departure monitoring function is operating, the monitoring status indicator 62 displays that effect.

Hereinafter, the contents of main processing performed in the lane departure and rear side monitoring apparatus 100a will be described in order.
(Description of lane marker detection processing)

  The lane marker detection unit 80 (FIG. 3), from the image I captured by the rear camera 50, the left and right lane markers L1, L2 of the traveling lane 20 and the left and right lane markers (L2, L3) of the adjacent lane (22 or 26). Or L1, L5). In FIG. 1A and FIG. 1B, each lane marker (L1, L2, L3, L5) is indicated by a solid line, but this can be detected by the same process even if it is drawn by a broken line. is there.

  An outline of the lane marker detection process will be described with reference to FIG. FIG. 4A shows an example of an image I behind the vehicle 10 captured by the rear camera 50 when the vehicle 10 is traveling on the traveling lane 20 of the road 30 shown in FIG. 1A. In the image I, luminance evaluation areas (windows) A1, A2,..., A5 for detecting a lane marker L2 indicating one end of the traveling lane 20 and a lane marker L1 indicating the other end of the traveling lane 20 are shown. ... C5 and a luminance evaluation area (window) for detecting a lane marker L3 indicating the far end of the adjacent lane 22 when viewed from the vehicle 10. B1, B2,..., B5, and luminance evaluation areas (windows) D1, D2,..., D5 for detecting the lane marker L5 (FIG. 1B) indicating the far end as viewed from the vehicle 10 in the adjacent lane 26. Are set respectively. Here, since it is generally not possible to determine whether the traveling lane 20 in which the vehicle 10 is traveling is in the state of FIG. 1A or in the state of FIG. 1B, as shown in FIG. The use area (window) is set on both sides of the travel lane 20.

  The rear camera 50 is mounted with a wide-angle lens and installed at the rear end of the vehicle 10 (for example, near the lower end of the trunk lid). In the example shown in FIG. A part is reflected.

  Here, the luminance evaluation areas (windows) A1, A2,... Are installed at preset initial positions where the lane marker L2 is assumed to be observed by the action of the window setting unit 84 (FIG. 3). . Each of the luminance evaluation areas A1, A2,... Has the same size, for example, about 1 meter in width and 80 cm in length, and about 5 are installed at an equal interval of about 5 m. . Therefore, as shown in FIG. 4A, each of the luminance evaluation areas A1, A2,... The number of installed luminance evaluation areas A1, A2,..., A5 is not limited to five, and a suitably determined number of luminance evaluation areas are set.

  The same applies to the other luminance evaluation regions (windows) B1, B2,..., C1, C2,.

  Next, a method for detecting the position of the lane marker L2 will be described with reference to FIG. 4B, taking the luminance evaluation region (window) A3 as an example. Note that the window A3 has a size of p3 pixels in the horizontal direction and q3 pixels in the vertical direction.

  By the operation of the lane marker detection unit 80 (FIG. 3), the brightness (luminance value) at the position where the luminance evaluation area (window) A3 is set in the image I is accumulated in the vertical direction of the luminance evaluation area A3. Process. That is, the luminance values for q3 pixels in the vertical direction of the luminance evaluation area A3 are accumulated, and a total sum Q of luminance values is obtained. When the same accumulation process is repeatedly performed for the p3 pixels in the horizontal direction of the luminance evaluation area A3, a luminance value accumulation curve shown in FIG. 4B is obtained. When the lane marker L2 is present at the position of the luminance evaluation area A3, the lane marker L2 is observed brightly with respect to the road surface, so that a cumulative value protruding at a position corresponding to the lane marker L2 is obtained.

  The cumulative curve of luminance values thus obtained is compared with the cumulative luminance threshold value Qth, and it is determined that the lane marker L2 is present in the region exceeding the cumulative luminance threshold value Qth. The midpoint of the exceeding range is set as the lane marker position x3. Then, by the action of the window setting unit 84 (FIG. 3), the position of the luminance evaluation area (window) A3 is changed so that the center in the left-right direction matches the lane marker position x3.

  Depending on the travel position of the vehicle 10, there is a possibility that the luminance evaluation area (window) A3 is set at a position outside the lane marker L2. Therefore, when the lane marker L2 is not found by performing the above-described processing, the search for the lane marker L2 is repeatedly performed while shifting the position of the luminance evaluation area A3 by several pixels left and right.

  The same processing is performed on all luminance evaluation areas (windows) A1, A2,..., A5, thereby calculating lane marker positions x1, x2,. The positions of the luminance evaluation areas A1, A2,..., A5 are changed so that the lane marker positions x1, x2,. A line connecting x2,..., x5 with a straight line or a curve is the detection result of the lane marker L2.

  .., C1, C2,..., D1, D2,.

  At this time, in the example of FIG. 4A, since no lane marker exists in the area where the luminance evaluation areas D1, D2,... Are set, the cumulative curve of luminance values does not exceed the cumulative luminance threshold Qth. Therefore, it is determined that no lane marker exists. That is, in the example of FIG. 4A, three lane markers L1, L2, and L3 are detected from the image I, respectively.

  This lane marker detection process is repeatedly executed by the lane marker detection unit 80 (FIG. 3) and the window setting unit 84 (FIG. 3), and the lane marker position x1, as the shape of the road 30 changes and the course of the vehicle 10 changes. The positions of x2,..., x5 and the luminance evaluation areas (windows) A1, A2,.

The luminance evaluation areas (windows) A1, A2,..., A5 assigned to the lane marker positions x1, x2,..., X5 are utilized in the subsequent luminance evaluation value calculation processing.
(Explanation of window setting process)

  By the lane marker detection process described above, the left and right lane markers L1 and L2 of the traveling lane 20 shown in FIGS. 1A and 1B and the left and right lane markers L2 and L3 (L1 and L5) of the adjacent lane 22 (26) are detected. The center of the luminance evaluation area (window) in the left-right direction is aligned with the position of the lane marker detected at times. In this way, the window setting process is performed.

Thereafter, since the lane marker detection process and the window setting process described above are repeatedly executed, the positions of the luminance evaluation areas (windows) A1, A2,..., A5 according to the position of the lane marker observed in the image I. Are corrected sequentially. Similarly, the lane marker detection process and the window setting process are repeated for the other luminance evaluation regions (windows) B1, B2,..., C1, C2,.
(Explanation of lane departure judgment processing)

  The lane departure determination unit 94 determines whether or not the vehicle 10 may deviate from the lane based on the positions of the left and right lane markers L1 and L2 of the traveling lane 20 detected by the lane marker detection process. Specifically, for example, with respect to the luminance evaluation areas A5 and C5 shown in FIG. 4C, the distance d1 from the center position E of the vehicle 10 to the lane marker L1 and the center position E of the vehicle 10 to the lane marker L2 The distance d2 is calculated, and it is determined whether there is a possibility of lane departure based on the magnitude relationship between the distance d1 and the distance d2.

  For example, in FIG. 4C, when the vehicle 10 deviates toward the lane marker L1, the distance d1> distance d2, and conversely, when the vehicle 10 deviates toward the lane marker L2, the distance d1 <distance d2.

That is, when either the distance d1 or the distance d2 becomes smaller than a predetermined value, it can be determined that the possibility that the vehicle 10 departs from the traveling lane is high.
(Explanation of night judgment process)

  Next, the contents of the night determination process for determining whether or not the surroundings of the vehicle 10 are in a dark environment will be described. This night determination process is performed in the night determination unit 82. The term “nighttime” as used herein includes, for example, a scene where the brightness of the surrounding environment is low, such as inside a tunnel, and assumes the brightness at which many vehicles turn on the headlamps.

The night determination unit 82 monitors the luminance gain value output from the rear camera 50. When the luminance gain value is higher than the predetermined value, it is determined that the ambient brightness is low, that is, at night. Hereinafter, the processing content is changed depending on whether or not it is determined that it is nighttime, and details will be described in a flowchart described later.
(Description of luminance evaluation value calculation processing)

  When it is determined that it is nighttime in the night determination process, the luminance distribution calculation unit 85 (FIG. 3) uses a window setting process to determine the lane marker (FIG. 4 (FIG. 4 (B)) of the adjacent lane 22 when the vehicle 10 is in the state of FIG. .., B1, B2,... corresponding to the position of each window as the luminance evaluation value EV. The luminance average value is calculated by averaging the luminance values of all the pixels in the region of the image I.

  Since the vehicle 10 may be in the state shown in FIG. 1B, the position of the lane marker (L1 shown in FIG. 4A) in the adjacent lane 26 and the lane marker L5 shown in FIG. 1B are observed. Then, the luminance evaluation areas (windows), that is, C1, C2,..., D1, D2,. Then, as the luminance evaluation value EV, the luminance average value is calculated by averaging the luminance values of all the pixels in the region of the image I corresponding to the position of each window.

  Here, in order to simplify the description, the luminance evaluation value EV calculated for the window Ai (i = 1, 2,...) Is represented by EV (Ai), and the window Bi (i = 1, 2,. The brightness evaluation value EV calculated for) is expressed as EV (Bi). Moreover, the vehicle 10 shall be in the state of FIG. 1A.

The luminance evaluation values EV (Ai) and EV (Bi) are calculated by averaging the luminance values of all the pixels in the area corresponding to the windows Ai and Bi in the image I. Among them, the luminance value of the pixels in the area corresponding to a part of the windows Ai and Bi may be averaged. For example, the luminance values of only the regions overlapping the detected lane markers L2 and L3 (L1 and L5) in the region corresponding to the windows Ai and Bi of the image I may be averaged. In this way, by evaluating the luminance value of only a part of the area corresponding to the windows Ai and Bi, the luminance distribution of the road surface can be accurately determined only by the brightness of the lane marker part without being affected by the brightness of the road surface. Can be evaluated.
(Description of luminance difference calculation processing)

  Next, in the luminance difference calculation unit 86 (FIG. 3), the windows 10 are equidistant from the vehicle 10 in the windows set at positions crossing the lane markers L2 and L3 of the adjacent lane 22 (in the case of FIG. 4C). A difference value between a luminance evaluation value EV (A3) calculated for a window arranged side by side at the position, for example, window A3, and a luminance evaluation value EV (B3) calculated for window B3 is calculated.

  Specifically, the lane marker L2 on the side of the adjacent lane 22 closer to the vehicle 10 is determined from the luminance evaluation value EV (B3) at the position of the adjacent lane 22 across the lane marker L3 on the far side of the adjacent lane 22 when viewed from the vehicle 10. The luminance evaluation value EV (A3) at the crossing position is subtracted. That is, the difference value EV (Bi) −EV (Ai) is calculated.

This luminance difference calculation process may be performed not only on the windows A3 and B3 but also on the windows Ai and Bi (i = 1 to 5) located at any distance behind the vehicle 10.
(Description of area determination processing)

  Next, in the area determination unit 88 (FIG. 3), the position of the adjacent lane 22 (in the case of FIG. 4C) crossing the lane marker L3 on the far side as viewed from the vehicle 10 is determined using the result of the luminance difference calculation process. Then, it is determined whether or not it is brighter than a predetermined value with respect to the position crossing the lane marker L2 on the side closer to the vehicle 10.

  This process is a process that is performed to determine whether or not there is another vehicle that has the headlights on the two adjacent lanes (24 in FIG. 1A).

  Hereinafter, an outline of the area determination process will be described with reference to FIGS. FIG. 5A shows the adjacent lane when the other vehicle 12 (FIG. 1A) whose headlamp is lit is approaching the vehicle 10 on the adjacent lane 22 in the state of FIG. 4C. It is a figure which shows an example of the time transition of the luminance evaluation value EV (Ai) and the luminance evaluation value EV (Bi) in 22 right and left ends.

  In this case, as shown in FIG. 5A, the luminance evaluation value EV (Ai) and the luminance evaluation value EV (Bi) increase with time. Then, the luminance evaluation value EV (Ai) on the lane marker L2 side close to the adjacent lane 22 when viewed from the vehicle 10 is slightly larger.

  On the other hand, FIG. 5B shows a state in which the headlamp is lit on the two adjacent lanes (not shown in FIG. 4C, 24 in FIG. 1A) in the state of FIG. 4C. An example of temporal transition of the luminance evaluation value EV (Ai) and the luminance evaluation value EV (Bi) at a position crossing the left and right ends of the adjacent lane 22 when the vehicle 14 (FIG. 1A) approaches the vehicle 10. FIG.

  In this case, as shown in FIG. 5B, the luminance evaluation value EV (Ai) and the luminance evaluation value EV (Bi) increase with time. Then, the luminance evaluation value EV (Bi) at a position crossing the lane marker L3 close to the two adjacent lanes (24 in FIG. 1A) when viewed from the vehicle 10 increases more greatly.

  Therefore, the time transition of the difference value EV (Bi) −EV (Ai) calculated by the luminance difference calculation process described above is as shown in FIG. Here, it is detected that the difference value EV (Bi) −EV (Ai) exceeds a preset brightness difference threshold value ΔEVth, and at the position crossing the lane marker L3, two adjacent lanes (in FIG. 1A). 24) It is determined that the headlight of the other vehicle 14 (FIG. 1A) traveling on the vehicle 24 is reflected. Based on this determination, it is determined that there is another vehicle 14 with the headlamps on the two adjacent lanes (24 in FIG. 1A).

Note that the luminance difference threshold value ΔEVth may be set to a value obtained through experiments or the like. For example, when the image I has a luminance value quantized to 8 bits, that is, a luminance value of 0 to 255, the lane marker L3 illuminated by the headlight of the other vehicle 14 is observed at the luminance value 150 by experiment. If this is the case, the luminance difference threshold value ΔEVth may be set to ΔEVth = 120 in consideration of a margin of 20%.
(Explanation of approaching vehicle detection process)

  Next, approaching vehicle detection processing performed in the approaching vehicle detection unit 92 (FIG. 3) will be described with reference to FIG.

  In the approaching vehicle detection process, an approaching vehicle detection frame T as shown in FIG. 6 is set at the position of the adjacent lane (22 in FIG. 1A or 26 in FIG. 1B) in the image I. This is done by analyzing the luminance distribution inside the detection frame T. The approaching vehicle detection frame T is set as a rectangular area along the lane in the adjacent lane 22 (26). It is assumed that the size of the approaching vehicle detection frame T and the position where the approaching vehicle detection frame T is set are determined in advance by experiments or the like.

Specifically, the luminance value in the approaching vehicle detection frame T is accumulated in the vertical direction, and the calculated accumulated value is divided by the accumulated number of pixels. As a result, the distribution of average luminance values shown in FIG. 6 is generated. The reason for dividing by the accumulated number of pixels is to normalize the accumulated value of the luminance value because the set approaching vehicle detection frame T becomes smaller as going farther. Here, as shown in FIG. 6, when an approaching vehicle (other vehicle 12) exists in the approaching vehicle detection frame T set in the adjacent lane 22, the area of the approaching vehicle (other vehicle 12) is different from the road surface in luminance difference. Therefore, a position where the average luminance value greatly changes is generated in the distribution of the average luminance value. In particular, when the approaching vehicle (other vehicle 12) lights the headlamps 12h, 12h, the average luminance value changes significantly. The approaching vehicle detection unit 92 detects a position where the average luminance value changes greatly (average luminance value change position). In some cases, a plurality of average luminance value change positions are detected. At that time, the center-of-gravity positions of the plurality of detected average luminance value change positions are detected. In this way, it is possible to detect the presence of an approaching vehicle (another vehicle 12) in the adjacent lane 22 by detecting the average luminance value change position or the center of gravity position.
(Explanation of approach time setting process for approaching vehicle detection)

  When it is determined by the above-described area determination processing that another vehicle 14 with a headlamp lit exists in two adjacent lanes (24 in FIG. 1A), an approaching vehicle is detected in the adjacent lane (22 in FIG. 1A). Suspend processing temporarily.

  The interruption time of the approaching vehicle detection process is set based on the relative speed between the vehicle 10 and the other vehicle 14 in the moving speed difference calculation unit 90 (FIG. 3). That is, when the relative speed in the direction in which the other vehicle 14 approaches the vehicle 10 is large, the irradiation range 14r (FIG. 1A) of the headlamp of the other vehicle 14 stays in the window Bi only for a short time. Set a short interruption time. On the other hand, when the relative speed between the vehicle 10 and the other vehicle 14 is small in the direction in which the other vehicle 14 approaches the vehicle 10, the irradiation range 14r (FIG. 1A) of the headlamp of the other vehicle 14 is longer than the window Bi. Therefore, the interruption time of the approaching vehicle detection process is set to be long.

  Since the other vehicle 12 traveling in the adjacent lane 22 detected by the approaching vehicle detection process is invalidated during the interruption time described above, the interruption time is hereinafter referred to as invalidation time Tn. .

  Here, the relative speed between the vehicle 10 and the other vehicle 14 is calculated by the moving speed difference calculation unit 90 (FIG. 3). Specifically, since the slope of the difference value EV (Bi) −EV (Ai) shown in FIG. 5C with respect to the time transition represents the relative speed between the vehicle 10 and the other vehicle 14, the value of the slope. The invalidation time Tn may be set according to the above. That is, when the gradient with respect to the time transition of the difference value EV (Bi) −EV (Ai) is large, the relative speed between the vehicle 10 and the other vehicle 14 is large, and therefore the headlamp illumination range 14r of the other vehicle 14 is short. Pass the window Bi. Therefore, the invalidation time Tn is set short. Conversely, when the slope of the difference value EV (Bi) −EV (Ai) with respect to the time transition is small, the invalidation time Tn is set to be long because the relative speed between the vehicle 10 and the other vehicle 14 is small. Note that a specific value of the invalidation time Tn is set by an experiment or the like.

Further, the method of interrupting the approaching vehicle detection process may be realized by canceling the approaching vehicle detection process itself, or the approaching vehicle detection process continues, but by invalidating all the results calculated there. It may be realized.
(Description of the flow of processing in the first embodiment)

  Next, the overall flow of processing performed in the first embodiment will be described with reference to the flowchart of FIG.

  (Step S100) Start determination of LDW and BSW is performed. Specifically, when the vehicle speed of the vehicle 10 is detected and a predetermined vehicle speed (for example, 30 km / h) is exceeded, monitoring by the LDW and BSW is started.

  (Step S102) The rear camera 50 captures an image behind the vehicle 10.

  (Step S104) The lane marker detection unit 80 performs lane marker detection processing. Details of the processing are as described above.

  (Step S106) The window setting unit 84 sets a plurality of windows at positions that cross the detected lane marker. Details of the processing are as described above.

  (Step S108) It is determined whether or not a lane departure warning is necessary, that is, whether or not the vehicle 10 may deviate from the traveling lane 20. When there is a possibility of deviating from the traveling lane 20, the process proceeds to step S110, and otherwise, the process proceeds to step S116.

  (Step S110) The buzzer 64 is sounded and a lane departure warning is output.

  (Step S112) It is determined whether a lane departure warning cancellation condition is satisfied. When the lane departure warning cancellation condition is satisfied, the process proceeds to step S114, and otherwise, step S112 is repeated. The LDW function is canceled when, for example, the lane departure / rear side monitoring switch 60 is operated.

  (Step S114) The buzzer 64 is stopped and the lane departure warning is canceled.

  (Step S116) The night determination unit 82 determines whether or not the surroundings of the vehicle 10 are dark. Specifically, when the luminance gain value output from the rear camera 50 is greater than or equal to a predetermined value, it is determined that the environment is dark and the process proceeds to step S118. In other cases, for example, when driving on a bright road in the daytime, the process proceeds to step S126.

  (Step S118) The region determination unit 88 determines whether there is another vehicle in the two adjacent lanes 24 (28).

  (Step S120) When it is determined that another vehicle 14 (18) exists in the two adjacent lanes 24 (28), the process proceeds to step S122, and otherwise, the process proceeds to step S126.

  (Step S <b> 122) The moving speed difference calculation unit 90 calculates the relative speed of the other vehicle 14 (or 18) with respect to the vehicle 10. A specific calculation method is as described above.

  (Step S124) A vehicle detection invalidation process for invalidating the other vehicle 12 (16) detected in the adjacent lane 22 (26) is performed over the time corresponding to the relative speed calculated in Step S122. Specific processing contents will be described later.

  (Step S126) The approaching vehicle detection unit 92 detects the other vehicle 12 (16) in the adjacent lane 22 (26). The specific detection method is as described above.

  (Step S128) It is determined whether an approaching vehicle alarm is necessary. Specifically, it is determined whether another vehicle 12 (16) that is an approaching vehicle is detected within a predetermined distance range behind the vehicle 10 in the adjacent lane 22 (26). When an approaching vehicle is detected, the process proceeds to step S130, and otherwise, the process proceeds to step S136.

  (Step S130) The left rear side approaching vehicle indicator 66a or the right rear side approaching vehicle indicator 66b corresponding to the direction in which the approaching vehicle is detected is turned on to notify the presence of the approaching vehicle. Further, when the left rear side approaching vehicle indicator 66a or the right rear side approaching vehicle indicator 66b is lit, when the blinker operation is performed on the lit indicator side, the buzzer 64 is sounded. To output an approaching vehicle warning.

  (Step S132) It is determined whether an approaching vehicle warning cancellation condition is satisfied. When the approaching vehicle warning cancellation condition is satisfied, the process proceeds to step S134, and otherwise, step S132 is repeated. The BSW function is canceled when, for example, the winker operation is canceled or when the vehicle speed of the vehicle 10 falls below a predetermined value (for example, 20 km / h).

  (Step S134) The left rear side approaching vehicle indicator 66a or the right rear side approaching vehicle indicator 66b that has been lit is extinguished, the buzzer 64 is stopped, and the approaching vehicle alarm is released.

  (Step S136) End determination of LDW and BSW is performed. Specifically, when the vehicle speed of the vehicle 10 is detected and falls below a predetermined value (for example, 20 km / h), the monitoring by the LDW and BSW is terminated.

  Although not described in the flowchart of FIG. 7, when the shift position of the vehicle 10 enters the reverse position, an image captured by the rear camera 50 is displayed on the monitor 70. Then, the driver of the vehicle 10 confirms the video behind the vehicle 10 displayed on the monitor 70 and performs the backward operation of the vehicle 10.

  Next, the flow of the vehicle presence / absence determination process for two adjacent lanes performed in step S118 of FIG. 7 will be described with reference to FIG.

  (Step S200) The vehicle presence / absence flag V2_f indicating the presence / absence of another vehicle in the two adjacent lanes 24 (28) is set to 0, and there is no other vehicle 14 (18) in the two adjacent lanes 24 (28). And

  (Step S202) It is determined whether or not the luminance evaluation value EV (Bi) of the window Bi (i = 1 to 5) exceeds the luminance threshold value EVth. When EV (Bi)> EVth, the process proceeds to step S204. Otherwise, the process returns to the main routine (FIG. 7).

  (Step S204) It is determined whether EV (Bi) −EV (Ai) exceeds the luminance difference threshold value ΔEVth and the vehicle presence / absence flag V2_f is zero. When the condition is satisfied, the process proceeds to step S206. Otherwise, the process returns to the main routine (FIG. 7).

  (Step S206) The vehicle presence / absence flag V2_f is set to 1, and it is determined that there is another vehicle 14 (18) in the two adjacent lanes 24 (28), and the time t0 at that time is stored. Thereafter, the process returns to the main routine (FIG. 7).

  Next, the flow of the vehicle detection invalidation process for adjacent lanes performed in step S124 in FIG. 7 will be described with reference to FIG.

  (Step S300) Based on the relative speed of the other vehicle 14 (18) with respect to the vehicle 10 calculated in Step S122 described above, vehicle detection that invalidates the other vehicle 12 (16) detected in the adjacent lane 22 (26). An invalidation time Tn that is a time interval for executing the invalidation processing is set.

  (Step S302) From the time t0 when the vehicle presence / absence flag V2_f becomes 1, it is determined whether or not the invalidation time Tn set in step S300 has elapsed. When the invalidation time Tn has elapsed, the process proceeds to step S304, and otherwise, the process proceeds to step S306.

  (Step S304) The vehicle presence / absence flag V2_f is set to 0, and it is determined that there is no other vehicle 14 (18) in the two adjacent lanes 24 (28). Thereafter, the process returns to the main routine (FIG. 7).

  (Step S306) The other vehicle 12 (16) is detected in the adjacent lane 22 (26), and the detection result of the other vehicle 12 (16) is invalidated. Thereafter, the process returns to step S302.

  Next, a specific second embodiment of the approaching vehicle detection device according to the present invention will be described with reference to the drawings.

  In the second embodiment, the present invention is applied to a lane departure and rear side monitoring apparatus 100b having the same function as that of the first embodiment. First, the functional configuration of the lane departure and rear side monitoring apparatus 100b will be described with reference to FIG.

  As shown in FIG. 10, the lane departure and rear side monitoring device 100b includes a lane marker L3 (on the far side when viewed from the vehicle 10 among the left and right lane markers L3, L2 (L1, L5) of the adjacent lane 22 (26). Changes in the luminance evaluation value EV (Bi) (EV (Di)) from the far rear side toward the nearest side of the vehicle 10 with respect to the window Bi (Di) set at a position crossing L5) This is different from the above-described lane departure and rear side monitoring apparatus 100a (FIG. 3) in that a luminance change calculation unit 87 is provided. The lane departure and rear side monitoring device 100b and the lane departure determination unit 94 constitute a camera ECU 52b.

  The function of the lane departure and rear side monitoring device 100b is that, in the region determination unit 88, an area where the luminance on the adjacent lane 22 (26) adjacent to the traveling lane 20 is high is the adjacent lane 22 (26 ) In the area where the headlight of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) adjacent to the far side of the vehicle is reflected, or traveling in the adjacent lane 22 (26) The determination method for determining whether or not the headlight of the vehicle 12 (16) is reflected is different from the lane departure and rear side monitoring device 100a.

  Hereinafter, the area determination method performed by the area determination unit 88 of the lane departure and rear side monitoring apparatus 100b will be described.

  In the area determination unit 88 of the lane departure and rear side monitoring apparatus 100b, the difference value of the luminance evaluation value EV calculated by the luminance difference calculation unit 86 is larger than the luminance difference threshold value ΔEVth as described above, and far away. For each window Bi (Di) set at a position that crosses the lane marker L3 (L5) on the side, a window (for example, B5 (B5 ( When the luminance evaluation value EV (Bi) (EV (Di)) changes in a direction exceeding the luminance threshold EVth with time, two lines are crossed across the lane marker L3 (L5). It is determined that the headlamp of the other vehicle 14 (18) traveling in the adjacent lane 24 (28) is reflected.

  11A and 11B, a window Bi (i = 1 to 5) is set at a position crossing the lane marker L3 as shown in FIG. 4C. As shown in FIG. FIG. 6 is a diagram in which the time transition of the luminance evaluation value EV (Bi) inside each window Bi is measured when the other vehicle 14 that lights up is approaching from the rear of the vehicle 10.

  As shown in FIG. 11, the luminance evaluation value EV (Bi) of each window Bi (i = 1 to 5) monotonously increases with time. As the other vehicle 14 approaches the vehicle 10, the irradiation range 14 r of the headlamps 14 h and 14 h of the other vehicle 14 shown in FIG. 1A gradually approaches the vehicle 10. The change in the luminance evaluation value EV (B1) observed in the window (for example, B1) is observed in order in the windows B2, B3, B4, and B5 that are closer to the vehicle 10 with time.

  Here, in FIG. 11, when the time when the luminance evaluation value EV (Bi) exceeds the luminance threshold value EVth is measured, the time t1, t2, t3 in order from the farthest window B1 to the most recent window B5 when viewed from the vehicle 10. , T4, t5 are measured.

  Then, for two windows adjacent to each other (for example, B1 and B2, B2 and B3,...), The time difference Δti (i = 1 to 4) at which the luminance evaluation value EV (Bi) exceeds the luminance threshold value EVth, respectively. When calculated, Δt1 = t2-t1, Δt2 = t3-t2, Δt3 = t4-t3, Δt4 = t5-t4 in order of approaching the vehicle 10.

  At this time, assuming that the other vehicle 14 traveling in the two adjacent lanes 24 is approaching the vehicle 10 at a constant relative speed, the headlights 14h and 14h of the other vehicle 14 shown in FIG. The irradiation range 14r approaches the vehicle 10 at a constant speed. That is, in FIG. 11, the gradients of the luminance evaluation values EV (Bi) are all equal. As described above, since the plurality of windows Bi are placed at equal intervals across the lane marker L3, the time differences Δti at which the luminance evaluation value EV (Bi) exceeds the luminance threshold EVth are all equal. .

  Therefore, the luminance change calculation unit 87 calculates the time difference Δti shown in FIG. 11 and compares these values. When it is determined that the time differences Δti (i = 1 to 4) are all within the predetermined time range, the luminance evaluation value EV (Bi) described in the first embodiment is larger than the luminance threshold value EVth. In addition, the difference value EV (Bi) −EV (Ai) is larger than the luminance difference threshold value ΔEVth, and the vehicle presence / absence flag V2_f is 0. It is determined that the headlight of the other vehicle 14 traveling in the lane 24 is reflected.

  Next, the flow of processing performed in the lane departure and rear side monitoring apparatus 100b will be described. Since the flow of processing performed in the lane departure and rear side monitoring apparatus 100b is substantially the same as the processing flow performed in the lane departure and rear side monitoring apparatus 100a shown in FIG. 7, only the differences will be described. To do.

  The difference between the two is the content of the process of determining the presence or absence of a vehicle in two adjacent lanes shown in step S118 of FIG. That is, the lane departure and rear side monitoring apparatus 100a performs the process shown in FIG. 8, while the lane departure and rear side monitoring apparatus 100b performs the process shown in FIG. Hereinafter, the process flow of FIG. 12 will be described.

  (Step S400) The vehicle presence / absence flag V2_f indicating the presence / absence of another vehicle in the two adjacent lanes 24 (28) is set to 0, and there is no other vehicle 14 (18) in the two adjacent lanes 24 (28). And

  (Step S402) It is determined whether or not the luminance evaluation value EV (Bi) of the window Bi (i = 1 to 5) is larger than the luminance threshold value EVth. When EV (Bi)> EVth, the process proceeds to step S404. Otherwise, the process returns to the main routine (FIG. 7).

  (Step S404) It is determined whether or not the difference value EV (Bi) −EV (Ai) is larger than the luminance difference threshold value ΔEVth and the vehicle presence / absence flag V2_f is zero. When the condition is satisfied, the process proceeds to step S406. Otherwise, the process returns to the main routine (FIG. 7).

  (Step S406) It is determined whether or not all the time differences Δti (i = 1 to 4) at which the difference value EV (Bi) −EV (Ai) exceeds the luminance difference threshold value ΔEVth are within a predetermined time range. If the condition is satisfied, the process proceeds to step S408; otherwise, the process returns to the main routine (FIG. 7).

  (Step S408) The vehicle presence / absence flag V2_f is set to 1, and it is assumed that there is another vehicle on the two adjacent lanes 24 (28), and the time t0 at that time is stored. Thereafter, the process returns to the main routine (FIG. 7).

  As described above, according to the lane departure and rear side monitoring apparatus 100a using the approaching vehicle detection device 95a according to the present invention configured as described above, the traveling lane of the road 30 having three or more lanes on one side. Lane marker L2, L3 which shows the boundary of at least the adjacent lane 22 (26) which the lane marker detection part 80 detected from the image I behind the vehicle 10 imaged with the rear camera 50 (imaging part) during driving | running | working 20 A window Ai and a lane marker L3 (L5) crossing the lane marker L2 (L1) detected by the lane marker detection unit 80 at a plurality of positions at different distances from the vehicle 10 at a position (L1, L5). Each of the windows Bi crossing each other, and the luminance distribution calculation unit 85 determines the luminance of the area corresponding to each window Ai, Bi in the image I. Luminance evaluation values EV (Ai) and EV (Bi) based on the cloth are respectively calculated, and the area determination unit 88 determines the left and right sides of the adjacent lane 22 (26) based on the luminance evaluation values EV (Ai) and EV (Bi). Among the lane markers L2 and L3 (L1, L5) indicating the boundary of the other vehicle 12 (16) traveling in the adjacent lane 22 (26) at a position crossing the lane marker L3 (L5) on the far side as viewed from the vehicle 10. The headlamp of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) adjacent to the far side of the adjacent lane 22 (26) as viewed from the vehicle 10 is reflected. And the approaching vehicle detection unit 92 determines that the headlight of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) is reflected. , Other vehicles traveling in the adjacent lane 22 (26) 12 (16) is not detected over the invalidation time Tn (predetermined time), so the headlamp is turned on and another vehicle 14 (18) traveling in the two adjacent lanes 24 (28) It is not erroneously determined that the vehicle is the other vehicle 12 (16) traveling on the adjacent lane 22 (26) by turning on. This makes it possible to reliably detect the approaching vehicle (other vehicle 12 (16)) traveling in the adjacent lane 22 (26).

  Further, according to the lane departure and rear side monitoring device 100a using the approaching vehicle detection device 95a according to the present invention configured as described above, the luminance evaluation values EV (Ai) and EV (Bi) are obtained from the image I. Among the areas corresponding to the windows Ai and Bi set in the middle, at least the lane markers L2 and L3 (L1 and L5) indicating the left and right boundaries of the adjacent lane 22 (26) are distant from the vehicle 10. Since the average luminance value of the region overlapping with the lane marker L3 (L5) is used, the brightness distribution on the road surface can be easily quantified, whereby the luminance value at the position crossing the lane marker L3 (L5) It is possible to efficiently determine whether the vehicle is the other vehicle 12 (16) in the lane 22 (26) or the other vehicle 14 (18) in the two adjacent lanes 24 (28).

  Furthermore, according to the lane departure and rear side monitoring device 100a using the approaching vehicle detection device 95a according to the present invention configured as described above, the area determination unit 88 determines the left and right boundaries of the adjacent lane 22 (26). Among the lane markers L2 and L3 (L1, L5) shown, the luminance evaluation value EV (Bi) of the region corresponding to the window Bi (Di) set at a position crossing the far side lane marker L3 (L5) when viewed from the vehicle 10 An area corresponding to the window Ai (Ci) set at a position crossing the lane marker L2 (L1) on the side close to the vehicle 10 in the adjacent lane, which is equidistant from the window Bi (Di) from (EV (Di)) When the value obtained by subtracting the luminance evaluation value EV (Ai) (EV (Ci)) of the image is larger than the positive luminance difference threshold value ΔEVth, the far side lane marker L3 (L5) is Because it is determined that the headlamps of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) are reflected in the position, the brightness distribution on the road surface can be easily determined. Can do.

  Then, according to the lane departure and rear side monitoring device 100b using the approaching vehicle detection device 95b according to the present invention configured as described above, the region determination unit 88 determines the left and right boundaries of the adjacent lane 22 (26). Among the lane markers L2 and L3 (L1, L5) shown, the luminance evaluation value EV (Bi) of the region corresponding to the window Bi (Di) set at a position crossing the far side lane marker L3 (L5) when viewed from the vehicle 10 An area corresponding to the window Ai (Ci) set at a position crossing the lane marker L2 (L1) on the side close to the vehicle 10 in the adjacent lane, which is equidistant from the window Bi (Di) from (EV (Di)) The value obtained by subtracting the luminance evaluation value EV (Ai) (EV (Ci)) is larger than the positive luminance difference threshold value ΔEVth, and the far side lane marker L3 (L5) is For each window Bi (Di) set at the cutting position, the luminance evaluation value EV (Bi) (EV (Di)) is timed from the far rear window as viewed from the vehicle 10 toward the window closest to the vehicle 10. When the vehicle changes in a direction exceeding the luminance threshold EVth, the vehicle crosses the far side lane marker L3 (L5) and is in front of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28). Since it is determined that the lighting is reflected, it is possible to more reliably determine the brightness distribution on the road surface.

  Further, according to the lane departure and rear side monitoring device 100b using the approaching vehicle detection device 95b according to the present invention configured as described above, the lane marker L3 on the far side of the adjacent lane 22 (26) when viewed from the vehicle 10 is used. The luminance evaluation value EV (Bi) (EV (Di)) of the area corresponding to each window Bi (Di) set at a position crossing (L5) exceeds the luminance threshold value EVth in each adjacent window. When each time difference Δti exceeding the luminance threshold EVth in each adjacent window Bi (Di) is within a predetermined time range, the vehicle 10 The luminance evaluation value EV (Bi) (EV (Di)) changes in the direction exceeding the luminance threshold EVth over time toward the latest window. To cross the luminance change of the position across the lane marker L3 (L5) of the distal, it can be easily and reliably detected. As a result, the movement of the irradiation range of the headlamp of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) that irradiate the far-side lane marker L3 (L5) can be easily and reliably performed. Judgment can be made.

  Furthermore, according to the lane departure and rear side monitoring apparatus 100a using the approaching vehicle detection device 95a according to the present invention configured as described above, the area determination unit 88 is configured to detect the adjacent lane 22 (26) when viewed from the vehicle 10. When it is determined that the headlight of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) is reflected at a position crossing the far side lane marker L3 (L5), the invalidation time Tn In order to invalidate the detection result of the other vehicle 12 (16) traveling in the adjacent lane 22 (26) in the approaching vehicle detection unit 92 over (predetermined time), the headlamp is turned on and the two adjacent The other vehicle 14 (18) traveling in the lane 24 (28) is not erroneously determined to be the other vehicle 12 (16) traveling in the adjacent lane 22 (26) by turning on the headlamp.

  Then, according to the lane departure and rear side monitoring device 100a using the approaching vehicle detection device 95a according to the present invention configured as described above, the region determination unit 88 is adjacent to the lane 22 (26) as viewed from the vehicle 10. When it is determined that the headlight of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) is reflected at a position crossing the far side lane marker L3 (L5), the invalidation time Tn In order to interrupt the detection of the other vehicle 12 (16) traveling in the adjacent lane 22 (26) in the approaching vehicle detection unit 92 for a predetermined time, the headlamp is turned on and the two adjacent lanes 24 are turned on. The other vehicle 14 (18) traveling on (28) is not erroneously determined to be the other vehicle 12 (16) traveling on the adjacent lane 22 (26) with the headlamp turned on.

  Further, according to the lane departure and rear side monitoring device 100a using the approaching vehicle detection device 95a according to the present invention configured as described above, the invalidation time Tn (predetermined time) is the vehicle 10 and the headlamp. Is set on the basis of the moving speed difference between the area where the vehicle is reflected and the adjacent lane 22 (due to the reflection of the headlight of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28). 26) erroneous detection of the other vehicle 12 (16) traveling on the vehicle 26) can be reliably prevented.

  In the first embodiment, the luminance difference calculation process is performed on any one set of windows Ai and Bi (i = 1 to 5) on the rear side of the vehicle 10, but this is performed on a plurality of sets of windows. You can go. That is, the luminance difference calculation processing is performed for each of the plurality of sets of windows Ai, Bi and Aj, Bj that are different in distance from the vehicle 10, and the difference value EV (Bi) -EV (Ai) and the difference value EV (Bj)- When both EV (Aj) are larger than the luminance difference threshold value ΔEVth, it is determined that a luminance difference has occurred between the left and right lane markers L3 and L2, so that the luminance at the position crossing the lane marker is not affected by sudden noise or the like. Distribution can be evaluated stably.

  In the first embodiment, the approaching vehicle detection unit 92 detects the other vehicle 12 (approaching vehicle) based on the luminance distribution inside the approaching vehicle detection frame T. It is not limited to this method. That is, a difference calculation (frame difference) between images taken continuously in time is performed on the image I taken from the rear side of the vehicle 10 to detect a region that has moved between the images. Alternatively, template matching may be performed using a template imitating the shape of the vehicle.

  In the first embodiment, the rear image 50 of the vehicle 10 is captured using only one rear camera 50. This is because the cameras are respectively located near the right door mirror and the left door mirror of the vehicle 10. The rear side of the vehicle 10 may be widely monitored with three cameras installed together with the rear camera 50. Thereby, the rear side of the vehicle 10 can be monitored with a wider field of view.

  In the first embodiment, the BSW function is activated according to the vehicle speed of the vehicle 10, which stores the lane number information of the road 30 in the map information of the car navigation system mounted on the vehicle 10. The BSW function is activated only when the currently traveling road 30 is a road with two or more lanes on one side, particularly when the road 30 with three or more lanes on one side is recognized as traveling. When the surrounding environment is dark (nighttime, inside the tunnel, etc.), as described in the first and second embodiments, the false detection of the other vehicle 14 (18) traveling in the two adjacent lanes 24 (28) is detected. An approaching vehicle may be detected by taking a preventive measure.

  As mentioned above, although the Example of this invention was explained in full detail with drawing, since an Example is only an illustration of this invention, this invention is not limited only to the structure of an Example. Of course, changes in design and the like within a range not departing from the gist are included in the present invention.

10 Vehicle 50 Rear camera 52a Camera ECU
54 Vehicle speed sensor 56 Blinker switch 60 Lane departure / rear side monitoring switch 64 Buzzer 66 Approaching vehicle indicator 70 Monitor 72 Reverse switch 80 Lane marker detection unit 82 Night determination unit 84 Window setting unit 85 Luminance distribution calculation unit 86 Luminance difference calculation unit 88 Area Determination unit 90 Moving speed difference calculation unit 92 Approaching vehicle detection unit 94 Lane departure determination unit 95a Approaching vehicle detection device 100a Lane departure and rear side monitoring device

Claims (8)

Other vehicles approaching from the rear of the vehicle in a state where a headlamp is lit on an adjacent lane of the traveling lane, which is applied to a vehicle traveling on a road lane having three or more lanes on one side An approaching vehicle detection device for detecting,
An imaging unit that captures an image including a road behind the vehicle;
A lane marker detection unit that detects at least lane markers indicating the left and right boundaries of the adjacent lane from the image, and
In the image, a window setting unit for setting a window crossing each lane marker detected by the lane marker detection unit at a plurality of positions at different distances from the vehicle,
A luminance distribution calculating unit for calculating a luminance evaluation value based on a luminance distribution of an area corresponding to each window in the image;
Based on the brightness evaluation value, among the lane markers indicating the left and right boundaries of the adjacent lane, the headlights of other vehicles traveling in the adjacent lane are reflected at positions that cross the far side lane marker as viewed from the vehicle. An area determination unit that determines whether or not the headlamps of other vehicles traveling in two adjacent lanes adjacent to the far side of the adjacent lane as viewed from the vehicle are reflected;
An approaching vehicle detection unit that detects another vehicle on the adjacent lane that approaches from the rear of the vehicle, and the region determination unit includes, among the lane markers that indicate left and right boundaries of the adjacent lane, the vehicle When it is determined that the headlamps of other vehicles traveling in the two adjacent lanes are reflected at a position crossing the far side lane marker as viewed from, the approaching vehicle detection unit, for a predetermined time, An approaching vehicle detection device that does not detect other vehicles on the adjacent lane.   2. The approaching vehicle detection device according to claim 1, wherein the brightness evaluation value is an average brightness value of at least a part of a region corresponding to each window in the image.   The area determination unit, from the luminance evaluation value of an area corresponding to a window set at a position crossing a lane marker on the far side as viewed from the vehicle, out of lane markers indicating left and right boundaries of the adjacent lane, When the value obtained by subtracting the luminance evaluation value of the area corresponding to the window set at a position crossing the lane marker on the side adjacent to the vehicle in the adjacent lane at an equal distance is larger than a positive luminance difference threshold value The approach according to claim 1, wherein it is determined that a headlight of another vehicle traveling in two adjacent lanes is reflected at a position crossing the far lane marker. Vehicle detection device.   The area determination unit, from the luminance evaluation value of an area corresponding to a window set at a position crossing a lane marker on the far side as viewed from the vehicle, out of lane markers indicating left and right boundaries of the adjacent lane, The value obtained by subtracting the luminance evaluation value of the area corresponding to the window set at a position crossing the lane marker on the side adjacent to the vehicle in the adjacent lane at an equal distance is greater than a positive luminance difference threshold value, and For each window set at a position crossing the far-side lane marker, the brightness evaluation value is a brightness threshold over time from a rear-far window as viewed from the vehicle toward the nearest window. At a position crossing the far-side lane marker when changing in a direction exceeding the head of another vehicle traveling in two adjacent lanes Approaching vehicle detection device according to claim 1 or claim 2, wherein determining that is crowded reflected.   The area determination unit has a luminance evaluation value of an area corresponding to each window set at a position crossing a lane marker on the far side of the adjacent lane when viewed from the vehicle exceeds the luminance threshold value in windows adjacent to each other. When each time difference exceeding the luminance threshold value in each adjacent window is within a predetermined time range, the window far from the rear as viewed from the vehicle is directed toward the window closest to the vehicle. The approaching vehicle detection device according to claim 4, wherein the brightness evaluation value is determined to have changed in a direction exceeding the brightness threshold over time.   When the area determination unit determines that the headlights of other vehicles traveling in the two adjacent lanes are reflected at a position crossing the lane marker on the far side of the adjacent lane when viewed from the vehicle, at a predetermined time. The approaching vehicle detection device according to any one of claims 1 to 5, wherein the approaching vehicle detection unit invalidates a detection result of another vehicle traveling in an adjacent lane.   When the area determination unit determines that the headlights of other vehicles traveling in the two adjacent lanes are reflected at a position crossing the lane marker on the far side of the adjacent lane when viewed from the vehicle, at a predetermined time. 6. The approaching vehicle detection device according to claim 1, wherein the approaching vehicle detection unit interrupts detection of another vehicle traveling in an adjacent lane.   The approaching vehicle detection device according to claim 6 or 7, wherein the predetermined time is set based on a difference in moving speed between the vehicle and a region in which the headlight is reflected.