JP2012227639A - Traveling support device and traveling support method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a traveling support device that detects a motorcycle traveling just behind a moving body without increasing number of imaging means, and to provide a traveling support method.SOLUTION: A visual line changing part 31 changes a line of sight so as to obtain a bird's eye view image of an image captured by a camera 10. An alignment part 32a aligns an image in a first predetermined area A1 provided from one adjacent lane to the side just behind a vehicle V across a lane marking DL and an image in a second predetermined area A2 provided from the other lane to the side just behind the vehicle V across a lane marking DL, captured at different times where the line of sight is changed, individually. A differential value detection part 32b detects a differential value for each of the aligned image data in the first and second predetermined areas A1 and A2 captured at different times. A following vehicle detection part 33a detects a following motorcycle on the basis of deviation between the detected differential value in the first predetermined area A1 and that in the second predetermined area A2.

Description

  The present invention relates to a driving support device and a driving support method.

  Conventionally, by capturing the rear side of the host vehicle with two cameras, setting a plurality of detection areas in the image, and calculating the shift amount of the images captured by the two cameras for each detection area, A vehicle obstacle detection device that calculates the distance to the vehicle has been proposed. In this apparatus, since a plurality of detection areas are set in the image, it is possible to detect the following two-wheeled vehicle (see Patent Document 1).

Japanese Patent No. 3077529

  However, in the conventional apparatus, since the detection area is provided on the side rear side of the own vehicle, it is not possible to detect a two-wheeled vehicle that exists immediately behind the own vehicle. In addition, when detecting a two-wheeled vehicle, images picked up by two cameras must be processed, and the number of image pickup means such as cameras increases.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to detect a two-wheeled vehicle directly behind a moving body without increasing the number of imaging means. It is an object to provide a driving support device and a driving support method capable of performing the above.

  In the driving support device of the present invention, a first predetermined area and a second predetermined area are set. The first predetermined area is provided from the adjacent lane on the rear side of one side of the moving body to the side just behind the moving body across the dividing line. The second predetermined area is provided from the adjacent lane at the rear of the other side of the moving body to the right side of the moving body across the dividing line. Then, the viewpoint conversion means converts the image obtained by the imaging into a bird's-eye view state, and the alignment means converts the viewpoint-converted first predetermined region image and the second predetermined image at different times. The image of the area is individually aligned. The difference value detection means detects the difference value from the images at different times that have been aligned. The following vehicle detection means detects the following two-wheeled vehicle from the distance between the detected difference value of the first predetermined region and the difference value of the second predetermined region.

  According to the present invention, the first predetermined region provided from the adjacent lane on the rear side of one side of the moving body to the immediate rear side of the moving body, and the adjacent lane on the other side of the moving body. The difference value is detected by aligning the positions of both images with the second predetermined area provided up to the right side of the moving body across the lane marking from the distance, and the two-wheeled vehicle is detected from the difference between the difference values. . Here, the two-wheeled vehicle directly behind is often running near one side of the lane, and the difference value between the first predetermined region and the second predetermined region is large only when one motorcycle is present immediately behind. It tends to show a value. For this reason, it is possible to detect the motorcycle immediately behind the difference between the two difference values. Further, since the two-wheeled vehicle is detected from the difference value between the first predetermined area and the second predetermined area of the image obtained by the imaging means, it is not necessary to provide a plurality of imaging means. Therefore, it is not necessary to increase the number of imaging means, and it is possible to detect the two-wheeled vehicle immediately behind the moving body.

It is a schematic block diagram of the driving assistance device concerning this embodiment, and shows the example in case the driving assistance device is carried in vehicles. It is a top view which shows the driving state of the vehicle shown in FIG. It is a block diagram which shows the detail of the computer shown in FIG. FIG. 4 is a top view showing an outline of processing of the alignment unit shown in FIG. 3, (a) showing a moving state of the vehicle, and (b) showing an outline of alignment. It is the schematic which shows the mode of the production | generation of the difference waveform by the adjacent vehicle detection part shown in FIG. It is a flowchart which shows an example of the driving assistance method which concerns on this embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a driving support device 1 according to the present embodiment, and shows an example in which the driving support device 1 is mounted on a vehicle V. As shown in FIG. 1, the driving support apparatus 1 includes a camera (imaging means) 10, a vehicle speed sensor 20, a calculator 30, and an alarm device 40.

  The camera 10 shown in FIG. 1 is mounted so that the optical axis is at an angle θ from the horizontal to the bottom at a height h in the rear part of the vehicle V. The camera 10 images the rear and side rear of the host vehicle V from this position. The vehicle speed sensor 20 detects the traveling speed of the vehicle V, and calculates the speed from the wheel speed detected by, for example, a wheel speed sensor that detects the rotational speed of the wheel. The computer 30 detects an adjacent vehicle on the vehicle rear side. The warning device 40 warns the driver of the host vehicle V when the adjacent vehicle detected by the computer 30 may come into contact with the host vehicle V.

  FIG. 2 is a top view showing a traveling state of the vehicle V shown in FIG. As shown in FIG. 2, the camera 10 images the vehicle rear side at a predetermined angle of view. At this time, in addition to the lane in which the host vehicle V travels, the right and left lanes can be imaged within the angle of view of the camera 10.

  In particular, the computer 30 of the driving support device 1 according to the present embodiment is configured so that the following vehicle such as an automobile or a motorcycle running directly behind the host vehicle V based on the images of the first predetermined area A1 and the second predetermined area A2. And an adjacent vehicle traveling in the adjacent lane is detected based on the images of the third predetermined area A3 and the fourth predetermined area A4.

  Here, the first predetermined area A1 is provided from the adjacent lane on the rear side of one side of the host vehicle V to the side immediately behind the host vehicle V across the dividing line DL. Further, the second predetermined area A2 is provided from the adjacent lane on the other side rear side of the host vehicle V to the side immediately behind the host vehicle V across the dividing line DL. That is, the first predetermined area A1 and the second predetermined area A2 are respectively set on the left and right sides of the travel lane so as to bisect the approximate center of the lane in which the host vehicle V travels (hereinafter referred to as the own lane). . Further, the third predetermined area A3 is provided at a position corresponding to an adjacent lane on one side rear of the host vehicle V, and the fourth predetermined area A4 corresponds to an adjacent lane on the other side rear of the host vehicle V. It is provided in the position to do.

  FIG. 3 is a block diagram showing details of the computer 30 shown in FIG. In FIG. 3, the camera 10, the vehicle speed sensor 20, and the alarm device 40 are also illustrated in order to clarify the connection relationship.

  As illustrated in FIG. 3, the computer 30 includes a viewpoint conversion unit (conversion unit) 31, a difference detection unit 32, and a moving body detection unit 33.

  First, the viewpoint conversion unit 31 inputs captured image data obtained by imaging with the camera 10, and converts the input captured image data into a bird's-eye image data in a bird's-eye view state. The state viewed from a bird's-eye view is a state viewed from the viewpoint of a virtual camera looking down from above, for example, vertically downward. This viewpoint conversion is executed as described in, for example, Japanese Patent Application Laid-Open No. 2008-219063.

  The difference detection unit 32 receives the bird's-eye image data converted by the viewpoint conversion unit 31, detects the difference between the bird's-eye image data at different times, and generates difference image data. The difference detection unit 32 includes an alignment unit (alignment unit) 32a and a difference value detection unit (difference value detection unit) 32b.

  The alignment unit 32a sequentially inputs the bird's-eye image data obtained by the viewpoint conversion of the viewpoint conversion unit 31, and aligns the positions of the inputted bird's-eye image data at different times. 4A and 4B are top views showing an outline of the processing of the alignment unit 32a shown in FIG. 3, where FIG. 4A shows the moving state of the vehicle V, and FIG. 4B shows the outline of alignment.

  As shown in FIG. 4A, it is assumed that the host vehicle V at the current time is located at V1, and the host vehicle V one hour before is located at V2. In addition, the other vehicle V is located in the rear direction of the own vehicle V and is in parallel with the own vehicle V, the other vehicle V at the current time is located at V3, and the other vehicle V one hour before is located at V4. Suppose you are. Furthermore, it is assumed that the host vehicle V has moved a distance d at one time. Note that “one hour before” may be a past time by a predetermined time (for example, one control cycle) from the current time, or may be a past time by an arbitrary time.

In this state, the bird's-eye image PB _t at the current time is as shown in Figure 4 (b). In the bird's-eye image PB _t, for the white line drawn on the road surface becomes a rectangular shape, but in a state of being relatively accurately viewed, and tilting for the other vehicle V3 is generated. Similarly, for the bird's-eye view image PB _{t-1 one} hour before, the section line drawn on the road surface is rectangular and is viewed from the top relatively accurately. A fall has occurred.

The alignment unit 32a performs alignment of the bird's-eye images PB _t and PB _t−1 as described above on the data. At this time, the alignment unit 32a is offset the bird's-eye view image PB _t-1 before one unit time, to match the position and bird's-eye view image PB _t at the current time. The offset amount d ′ is an amount corresponding to the moving distance d shown in FIG. 4A, and is determined based on the signal from the vehicle speed sensor 20 and the time from one time before to the current time.

The difference value detector 32b detects the difference values of the first to fourth predetermined areas A1 to A4. In detecting the difference value, first, the difference value detection unit 32b takes the difference between the bird's-eye images PB _t and PB _t−1 and generates data of the difference image PD _t . Here, the pixel value of the difference image PD _t may be an absolute value of the difference between the pixel values of the bird's-eye images PB _t and PB _t−1 , and the absolute value is specified in order to cope with a change in the illuminance environment. “1” may be set when the value is exceeded, and “0” may be set when the value is not exceeded.

And after the above processes, the difference detection part 32b detects a difference value. At this time, if the pixel value of the difference image PD _t is an absolute value of the difference between the pixel values of the bird's-eye images PB _t and PB _t−1 , the difference detection unit 32b may, for example, include first to fourth predetermined regions. The difference value is detected by adding the pixel values for all the pixels in the areas A1 to A4. The pixel value of the difference image PD _t is set to “1” when the absolute value obtained by converting the difference between the pixel values of the bird's-eye images PB _t and PB _t−1 to an absolute value exceeds a specified value. In this case, the difference value detection unit 32b detects the difference value by adding the number of pixels set to “1” in each of the first to fourth predetermined areas A1 to A4, for example.

  The moving body detection unit 33 detects a subsequent vehicle or an adjacent vehicle in the first to fourth predetermined areas A1 to A4, and includes a subsequent vehicle detection unit (subsequent vehicle detection means) 33a and an adjacent vehicle detection unit ( Adjacent vehicle detection means) 33b.

  The following vehicle detection unit 33a detects the following vehicle based on a difference value between the first predetermined area A1 and the second predetermined area A2. At this time, the subsequent vehicle detection unit 33a determines whether the subsequent vehicle is an automobile or a two-wheeled vehicle. The adjacent vehicle detection unit 33b detects an adjacent vehicle traveling in the adjacent lane based on a difference value between the third predetermined area A3 and the fourth predetermined area A4. In addition to the method of detecting the adjacent vehicle from the difference value, there is a method of obtaining from the difference waveform.

  Next, details of detection of the following vehicle by the following vehicle detection unit 33a will be described. As described above, the subsequent vehicle detection unit 33a inputs the difference value of the first predetermined area A1 and the difference value of the second predetermined area A2 detected by the difference value detection unit 32b. Then, the subsequent vehicle detection unit 33a determines whether the difference value of the first predetermined area A1 is equal to or greater than a predetermined value, and determines whether the difference value of the second predetermined area A2 is equal to or greater than the predetermined value.

  Next, when the difference value in only one of the first predetermined area A1 and the second predetermined area A2 is greater than or equal to the predetermined value, the subsequent vehicle detection unit 33a If it is determined that the vehicle is a two-wheeled vehicle and the difference value between the two predetermined areas A1 and A2 is equal to or greater than the predetermined value, it is determined that the following vehicle is an automobile. The subsequent vehicle detection unit 33a determines that there is no subsequent vehicle when the difference value is not greater than or equal to the predetermined value for any of the predetermined areas A1 and A2.

  Here, the reason for determining as described above is as follows. First, when there is a subsequent vehicle immediately behind the host vehicle V, the subsequent vehicle is detected as a difference, so the difference value tends to increase. Also, motorcycles often run closer to one side of the lane. For this reason, the difference value of only one of the first and second predetermined areas A1 and A2 tends to increase. On the other hand, when the following vehicle is an automobile, the difference between both the first and second predetermined areas A1 and A2 tends to increase because the automobile cannot travel to one side of the lane. It is in.

  Thus, the subsequent vehicle detection unit 33a according to the present embodiment is configured to be able to detect the subsequent two-wheeled vehicle from the difference between the difference values of the first and second predetermined areas A1 and A2.

  Details of detection of an adjacent vehicle by the adjacent vehicle detection unit 33b will be described. As described above, the adjacent vehicle detection unit 33b inputs the difference value of the third predetermined area A3 and the difference value of the fourth predetermined area A4 detected by the difference value detection unit 32b. Then, the adjacent vehicle detection unit 33b determines whether the difference value of the third predetermined area A3 is equal to or greater than a predetermined threshold value, and determines whether the difference value of the fourth predetermined area A4 is equal to or greater than the predetermined threshold value. To do.

  Next, when the adjacent vehicle detection unit 33b determines that the difference value of the third predetermined area A3 is equal to or greater than a predetermined threshold, the adjacent vehicle detection unit 33b determines that there is an adjacent vehicle of the third predetermined area A3. When it is determined that the difference value of the fourth predetermined area A4 is equal to or greater than a predetermined threshold, it is determined that there is an adjacent vehicle in the fourth predetermined area A4.

Again, the structure of the computer 30 is demonstrated based on FIG. The computer 30 includes a threshold changing unit (threshold changing means) 34. The threshold value changing unit 34 changes the threshold value of the threshold value processing that is performed when the adjacent vehicle detecting unit 33b detects the adjacent vehicle.

  More specifically, when the subsequent vehicle detection unit 33a determines that the succeeding vehicle is a two-wheeled vehicle, the threshold value changing unit 34 determines that the two-wheeled vehicle is present in the third predetermined region A3 and the fourth predetermined region A4. The predetermined threshold is lowered for the region on the other side. Here, in the predetermined area on the side where the two-wheeled vehicle is present among the third predetermined area A3 and the fourth predetermined area A4, it is difficult to detect the adjacent vehicle. For this reason, it is easy to detect the adjacent vehicle by lowering the threshold value, and the frequency of detection omission of the adjacent vehicle can be reduced.

  In addition, as described below, the adjacent vehicle detection unit 33b may detect the adjacent lane by converting the difference value into a waveform.

FIG. 5 is a schematic diagram illustrating how the differential waveform is generated by the adjacent vehicle detection unit 33b illustrated in FIG. In the example shown in FIG. 5, only the third predetermined area A3 is described for convenience, but the same applies to the fourth predetermined area A4. As shown in FIG. 5, the adjacent vehicle detection unit 33b generates a differential waveform DW _t from a portion corresponding to the third predetermined area A3 in the differential image PD _t . At this time, the adjacent vehicle detection unit 33b generates the differential waveform DW _t along the direction in which the three-dimensional object falls due to the viewpoint conversion.

Specifically, first, the adjacent vehicle detection unit 33b defines a line La in the direction in which the three-dimensional object falls on the data of the difference image DW _t . Then, the adjacent vehicle detection unit 33b counts the number of difference pixels DP indicating a predetermined difference on the line La. Here, the pixel value of the difference image DW _t is expressed by “0” and “1”, and the number of pixels indicating “1” is counted.

  The adjacent vehicle detection unit 33b counts the number of difference pixels DP, and then obtains an intersection CP between the line La and the ground line L1. Then, the adjacent vehicle detection unit 33b associates the intersection point CP with the count number, determines a horizontal axis position (a position on the vertical axis in FIG. 5) based on the position of the intersection point CP, and determines the vertical axis position from the count number. (Position on the horizontal axis in FIG. 5) is determined.

Similarly, the adjacent vehicle detection unit 33b defines a line in the direction in which the three-dimensional object falls, counts the number of difference pixels DP, determines the horizontal axis position based on the position of the intersection CP, and counts ( The vertical axis position is determined from the number of difference pixels DP). The adjacent vehicle detection unit 33b generates the differential waveform DW _t by sequentially repeating the above and making a frequency distribution.

As shown in FIG. 5, the line La and the line Lb in the direction in which the three-dimensional object collapses have different distances overlapping the fourth predetermined area A4. For this reason, if the fourth predetermined region A4 is filled with the difference pixels DP, the number of difference pixels DP is greater on the line La than on the line Lb. For this reason, when determining the vertical axis position from the count number of the difference pixel DP, the adjacent vehicle detection unit 33b normalizes based on the distance at which the lines La and Lb in the direction in which the three-dimensional object falls and the detection area A1 overlap. To do. As a specific example, in FIG. 5, there are six difference pixels DP on the line La, and there are five difference pixels DP on the line Lb. Therefore, in determining the vertical axis position from the count number in FIG. 5, the adjacent vehicle detection unit 33b normalizes the count number by dividing it by the overlap distance. Thus, as shown in the difference waveform DW _t, the line La on the direction the three-dimensional object collapses, the value of the differential waveform DW _t corresponding to Lb is substantially the same.

After the generation of the differential waveform DW _t , the adjacent vehicle detection unit 33b determines whether or not the peak of the differential waveform DW _t is _equal to or greater than a predetermined threshold value. Here, when the peak of the difference waveform DW _t is not equal to or greater than the predetermined threshold, that is, there is almost no difference, and it is considered that there is no three-dimensional object in the captured image P. For this reason, the adjacent vehicle detection unit 33b determines that there is no adjacent vehicle. On the other hand, when it is determined that the peak of the difference waveform DW _t is equal to or greater than the predetermined value, the three-dimensional object detection unit 33 determines that the adjacent vehicle is traveling in the adjacent lane.

  Next, the driving support method according to the present embodiment will be described with reference to a flowchart. FIG. 6 is a flowchart showing an example of the driving support method according to the present embodiment.

  First, as shown in FIG. 6, the computer 30 determines whether or not the host vehicle V is equal to or lower than a predetermined speed based on a signal from the vehicle speed sensor 20 (S1). When it is determined that the host vehicle V is equal to or lower than the predetermined speed (S1: YES), the alignment unit 32a performs alignment. And the difference value detection part 32b detects the difference of 3rd and 4th predetermined area | region A3, A4 (S2).

  Next, the adjacent vehicle detection unit 33b determines whether one or both of the third and fourth predetermined areas A3 and A4 is equal to or greater than a predetermined threshold (S3). When it is determined that one or both of the third and fourth predetermined areas A3 and A4 are equal to or greater than the predetermined threshold (S3: YES), the adjacent vehicle detection unit 33b determines that there is an adjacent vehicle, and accordingly. Is transmitted to the alarm device 40. Thereby, the alarm device 40 issues an alarm (S4), and the process shown in FIG. 6 ends.

  On the other hand, when it is determined that one or both of the third and fourth predetermined areas A3 and A4 are not equal to or greater than the predetermined threshold (S3: NO), the subsequent vehicle detection unit 33a determines that there is no adjacent vehicle. And the difference value detection part 32b detects the difference of 1st and 2nd predetermined area | region A1, A2 (S5).

  Thereafter, the succeeding vehicle detection unit 33a determines whether one or both of the first and second predetermined areas A1 and A2 are equal to or greater than a predetermined value (S6). When it is determined that one or both of the first and second predetermined areas A1 and A2 are not equal to or greater than the predetermined value (S6: NO), the threshold changing unit 34 sets the predetermined threshold used when determining the adjacent vehicle. “High” is set (S7). Thereafter, the process shown in FIG. 6 ends.

  When it is determined that one or both of the first and second predetermined areas A1 and A2 are equal to or greater than the predetermined value (S6: YES), the following vehicle detection unit 33a determines whether only one is equal to or greater than the predetermined value. Judgment is made (S8). When it is determined that only one of them is equal to or greater than the predetermined value (S8: YES), the subsequent vehicle detection unit 33a determines that a two-wheeled vehicle is present immediately behind the host vehicle V. Then, the threshold value changing unit 34 sets the predetermined threshold value used in determining the adjacent vehicle to “low” (S9). Thereafter, the process shown in FIG. 6 ends. Here, in the predetermined area on the side where the two-wheeled vehicle is present among the third predetermined area A3 and the fourth predetermined area A4, it is difficult to detect the adjacent vehicle. For this reason, it is easy to detect the adjacent vehicle by lowering the predetermined threshold value, and the frequency of detection omission of the adjacent vehicle can be reduced.

  On the other hand, when it is determined that only one of them is not equal to or greater than the predetermined value (S8: NO), that is, when both are equal to or greater than the predetermined value, the subsequent vehicle detection unit 33a determines that there is an automobile immediately behind the host vehicle V. Then, the threshold value changing unit 34 sets the predetermined threshold value used in the determination of the adjacent vehicle to “high” (S7). Thereafter, the process shown in FIG. 6 ends.

  By the way, when it is determined that the host vehicle V is not below the predetermined speed (S1: NO), the alignment unit 32a performs alignment. Then, the threshold value changing unit 34 sets the predetermined threshold value used in the determination of the adjacent vehicle to “high” (S10).

Next, the difference value detection unit 32b detects the difference between the third and fourth predetermined areas A3 and A4 (
S11). And the adjacent vehicle detection part 33b judges whether any one or both in 3rd and 4th predetermined area | region A3, A4 is more than a predetermined threshold value (S12). When it is determined that one or both of the third and fourth predetermined areas A3 and A4 are equal to or greater than the predetermined threshold (S12: YES), the adjacent vehicle detection unit 33b determines that there is an adjacent vehicle, and accordingly. Is transmitted to the alarm device 40. Thereby, the alarm device 40 issues an alarm (S4), and the process shown in FIG. 6 ends.

  On the other hand, when it is determined that one or both of the third and fourth predetermined areas A3 and A4 are not equal to or greater than the predetermined threshold (S12: NO), the process shown in FIG.

  Thus, according to the driving assistance device 1 and the driving assistance method according to the present embodiment, the vehicle is provided from the adjacent lane on the rear side of one side of the host vehicle V to the side immediately behind the host vehicle V across the dividing line DL. Both the first predetermined area A1 and the second predetermined area A2 provided from the adjacent lane on the other side rear side of the host vehicle V to the immediate rear side of the host vehicle V across the dividing line DL. The difference value is detected by matching the positions, and the two-wheeled vehicle is detected from the difference between the difference values. Here, the two-wheeled vehicle directly behind is often running near one side of the lane, and the difference value between the first predetermined region A1 and the second predetermined region A2 is only one when the two-wheeled vehicle is directly behind. Tend to show large values. For this reason, it is possible to detect the motorcycle immediately behind the difference between the two difference values. Further, since the two-wheeled vehicle is detected from the difference value between the first predetermined area A1 and the second predetermined area A2 of the image obtained by the camera 10, there is no need to provide a plurality of cameras 10. Therefore, it is not necessary to increase the number of cameras 10 and it is possible to detect a motorcycle just behind the host vehicle V.

  The first predetermined area A1 and the second predetermined area A2 are set on the left and right sides of the lane so as to bisect from the vicinity of the approximate center line of the lane in which the host vehicle V travels. When a two-wheeled vehicle is about to overtake its own vehicle, it can be predicted from which side the vehicle will pass.

  Further, when the difference value of only one of the first predetermined area A1 and the second predetermined area A2 is equal to or greater than the predetermined value, the subsequent vehicle is determined to be a two-wheeled vehicle, and the first predetermined area A1 and the second predetermined area A2 When the difference value between the predetermined area A2 and the predetermined area A2 is equal to or greater than the predetermined value, the subsequent vehicle is determined to be an automobile. Here, only one of the difference values between the first predetermined area A1 and the second predetermined area A2 tends to show a large value for a motorcycle at the rear, but the car travels only on one side of the lane. The difference value between the two is not less than a predetermined value. Therefore, it can be determined whether the following vehicle is a two-wheeled vehicle or an automobile.

  Further, when the difference value is detected for the image of the third predetermined area A3 and the image of the fourth predetermined area A4 provided in the adjacent lane, and the difference value is equal to or greater than a predetermined threshold, there is an adjacent vehicle. Then detect. Further, when it is determined that the following vehicle is a two-wheeled vehicle, a predetermined threshold value is lowered for an area of the third predetermined area A3 and the fourth predetermined area A4 on which the subsequent vehicle is determined to exist. Here, in the predetermined area on the side where the two-wheeled vehicle is present among the third predetermined area A3 and the fourth predetermined area A4, it is difficult to detect the adjacent vehicle. For this reason, it is easy to detect the adjacent vehicle by lowering the threshold value, and the frequency of detection omission of the adjacent vehicle can be reduced.

In addition, when the speed of the host vehicle V is equal to or lower than the predetermined speed, a predetermined threshold value is lowered for an area of the third predetermined area A3 and the fourth predetermined area A4 on which the subsequent vehicle is determined to exist. To do. Here, when the speed is equal to or lower than the predetermined speed, the two-wheeled vehicle immediately behind the vehicle easily overtakes the own vehicle, and the two-wheeled vehicle tries to overtake the own vehicle V and the third predetermined area A3 or the fourth predetermined area A.
4 is often located between. For this reason, it is often difficult to detect adjacent vehicles. Therefore, the predetermined threshold can be appropriately changed by lowering the predetermined threshold only when the speed of the host vehicle V is equal to or lower than the predetermined speed.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and modifications may be made without departing from the spirit of the present invention.

  For example, in the above embodiment, the vehicle speed of the host vehicle V is determined based on a signal from the speed sensor 20, but the present invention is not limited to this, and the speed may be estimated from a plurality of images at different times. In this case, a vehicle speed sensor becomes unnecessary, and the configuration can be simplified.

In the above-described embodiment, the captured image at the current time and the image one hour before are converted into a bird's-eye view and the converted bird's-eye view is aligned. However, the present invention is not limited to this. That is, the current image and the previous image are aligned, a difference image PD _t is generated from the difference between the aligned images, and the difference image PD _t is converted into a bird's eye view. Good.

  Further, in the above embodiment, the adjacent vehicle and the following vehicle are detected from the difference value. However, if this difference value is only the difference value between the image obtained at the current time and the image obtained before one control cycle. Alternatively, it may be a difference value between an image obtained at the current time and an image obtained before several control cycles, or a total value or an average value obtained by accumulating the obtained difference values for a plurality of times. It may be.

DESCRIPTION OF SYMBOLS 1 ... Driving assistance apparatus 10 ... Camera (imaging means)
20 ... Vehicle speed sensor 30 ... Computer 31 ... Viewpoint conversion unit (viewpoint conversion means)
32 ... Difference detection unit 32a ... Positioning unit (positioning means)
32b ... Difference value detection unit (difference place detection means)
33 ... Moving body detection unit 33a ... Subsequent vehicle detection unit (subsequent vehicle detection means)
33b ... Adjacent vehicle detection unit (adjacent vehicle detection means)
34 ... Threshold change unit (threshold change means)
40 ... alarm devices A1 to A4 ... predetermined region CP ... intersection DL ... partition line DP ... difference pixel DW _t ... difference waveform L1 ... ground line La, Lb ... line PB _{t in the} direction in which the three-dimensional object collapses ... bird's-eye view image PD _t ... Difference image V ... Own vehicle

Claims (6)

An imaging means mounted on the rear of the mobile body and imaging the rear of the mobile body;
Viewpoint conversion means for converting the viewpoint of the image obtained by imaging by the imaging means to a bird's-eye view;
Images of a first predetermined area provided at a different time when the viewpoint is converted by the viewpoint conversion unit, from the adjacent lane on the rear side of the one side of the moving body to a side immediately after the moving body, across the dividing line; Positioning means for individually aligning the positions of the second predetermined area images provided from the adjacent lane on the other side rear side of the moving body to the immediate rear side of the moving body across a dividing line;
Difference value detecting means for detecting difference values of the image data of the first predetermined area and the second predetermined area at different times aligned by the alignment means;
Subsequent vehicle detection means for detecting the following two-wheeled vehicle from the difference between the difference value of the first predetermined area detected by the difference value detection means and the difference value of the second predetermined area;
A driving support apparatus comprising: The first predetermined area and the second predetermined area are respectively set on the left and right sides of the lane so as to be divided into two substantially from the vicinity of the center line of the lane in which the moving body travels. The travel support device according to 1. When the difference value of only one of the first predetermined area and the second predetermined area is greater than or equal to a predetermined value, the subsequent vehicle detecting means determines that the subsequent vehicle is a two-wheeled vehicle, and the first predetermined area is the first predetermined area. The driving support device according to claim 2, wherein if the difference value between the area and the second predetermined area is equal to or greater than a predetermined value, the subsequent vehicle is determined to be an automobile. An adjacent vehicle detecting means for detecting an adjacent vehicle traveling in an adjacent lane adjacent to a lane in which the moving body travels;
Threshold value changing means for changing a threshold value of threshold processing performed when the adjacent vehicle detection means detects an adjacent vehicle; and
The positioning means includes an image of a third predetermined area provided in an adjacent lane at the rear of one side of the moving body at a different time when the viewpoint is converted by the viewpoint converting means, and the other side of the moving body. For the image of the fourth predetermined area provided in the rear adjacent lane, individually align the position,
The difference value detection means detects a difference value of each of the image data of the third predetermined area and the fourth predetermined area at different times aligned by the alignment means,
When the difference value of either the third predetermined area or the fourth predetermined area detected by the difference value detecting means is greater than or equal to a predetermined threshold, the adjacent vehicle detection means Detects that it exists,
The threshold value changing means, when the succeeding vehicle detecting means judges that the succeeding vehicle is a two-wheeled vehicle, of the third predetermined area and the fourth predetermined area on the side where the succeeding vehicle is judged to exist. The driving support device according to any one of claims 1 to 3, wherein the predetermined threshold is lowered for a region. When the speed of the moving body is equal to or lower than a predetermined speed, the threshold value changing unit is configured to determine, on the side of the third predetermined area and the fourth predetermined area, on the side where it is determined that a subsequent vehicle exists. The driving support device according to claim 4, wherein the predetermined threshold value is lowered. An imaging step of imaging the rear of the moving body from the rear of the moving body;
A viewpoint conversion step of converting the viewpoint of the image obtained by the imaging in the imaging step to a bird's-eye view;
Images of a first predetermined area provided at different times when the viewpoint is converted in the viewpoint conversion step, from adjacent lanes on the rear side of the one side of the moving body to a position just behind the moving body across the dividing line; An alignment step for individually aligning the position of the second predetermined area provided on the other side of the moving body from the adjacent lane on the rear side of the moving body to the immediate rear side of the moving body,
A difference value detection step of detecting a difference value between the image data of the first predetermined region and the second predetermined region at different times aligned in the alignment step;
A succeeding vehicle detecting step of detecting a succeeding two-wheeled vehicle from a gap between the difference value of the first predetermined region and the difference value of the second predetermined region detected in the difference value detecting step;
A driving support method characterized by comprising:

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