JP2015087969A - Column traveling device and traffic accident prevention device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which a device configuration becomes complicated and expensive since dedicated communication system, laser and ultrasonic wave are used for measuring distance and azimuth with respect to a vehicle traveling ahead when performing column traveling.SOLUTION: A column traveling device loaded in a rear vehicle performing column traveling by following a preceding vehicle traveling ahead, includes: an imaging part which images a rear number plate of the preceding vehicle; a number recognition part which recognizes the rear number plate from an image imaged by the imaging part to acquire characters or the like of the number plate; an azimuth and distance operation part which calculates the azimuth and distance with respect to the preceding vehicle on the basis of the position of the rear number plate in the image and the size of the characters or the like; and a control part which controls the traveling operation of the rear vehicle so as to follow the preceding vehicle on the basis of the azimuth and the distance.

Description

  The present invention relates to a row running apparatus that is mounted on a vehicle and performs row running for a vehicle ahead.

Convoy travel is being studied as a technology for automatic vehicle travel. In the platooning, when the traveling control of the second and subsequent vehicles is performed, information on the distance from the vehicle traveling immediately before and information on the direction of the vehicle is necessary.
Conventionally, in order to acquire distance and azimuth information, a dedicated communication system, a laser, and an ultrasonic wave are mounted on the vehicle, and the distance and azimuth are measured using these devices. In some cases, a central device was needed to control the entire device.
In recent years, devices for preventing rear-end collisions, driving assistance, and warnings have been adopted for general vehicles. In these general vehicles, prevention of a rear-end collision is performed by using a white line recognition or a method of detecting an object by emitting a laser or an ultrasonic wave in front (see, for example, Patent Documents 1 to 4).

Japanese Patent No. 3059627 JP-A-11-321380 JP 2000-68923 A Japanese Patent No. 3622706 JP 2007-172227 A

When performing platooning, a dedicated communication system, laser, and a dedicated device for measuring the distance and direction of the vehicle traveling in front using ultrasonic waves are required, and the configuration of the device is complicated or expensive. was there.
In addition, when using white line recognition with devices that prevent rear-end collisions, assist driving, and warn that are used in general vehicles, the method of detecting an object by emitting laser or ultrasonic waves from the front position of the vehicle will misrecognize the object. There was a problem that it was easy to do and the reliability was low.

  The present invention has been made in order to solve the above-mentioned problems, and with a simple configuration, by knowing the position and direction of a vehicle existing in front of or behind the vehicle, the speed and direction of the vehicle are corrected. It is an object of the present invention to provide a convoy travel apparatus capable of performing convoy travel.

The convoy travel device according to the present invention is a convoy travel device mounted on a rear vehicle that follows a forward vehicle traveling forward and performs a convoy travel, and an imaging unit that images a rear license plate of the front vehicle; A number recognizing unit that recognizes the rear license plate from the image captured by the imaging unit and obtains characters or numbers described in the rear license plate; and the image of the rear license plate recognized by the number recognizing unit. Based on the middle position and the letters or numbers acquired by the number recognition unit, the azimuth in which the front vehicle is located relative to the rear vehicle, and the azimuth for calculating the distance between the rear vehicle and the front vehicle, A distance calculation unit;
Based on the azimuth and the distance, the control unit is configured to control a traveling operation of the rear vehicle so that the rear vehicle follows the front vehicle.

According to this invention, it is possible to know the position and direction of a vehicle existing in front of or behind the target vehicle with a simple device configuration, and the target vehicle corrects its speed and direction and performs platooning. be able to.
In general vehicles, it is possible to prevent rear-end collisions, assist driving, and issue warnings with a simple device configuration.
Further, by analyzing the distance and direction in time series, it is possible to determine whether the vehicle traveling around is approaching or moving away from the host vehicle, and the possibility of collision can be determined.

It is a figure which shows the structure of the convoy travel apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the positional relationship of the vehicle which performs platooning which concerns on Embodiment 1 of this invention. It is an example of the image 100 imaged with the camera mounted in the back vehicle which concerns on Embodiment 1 of this invention. It is a flowchart which shows operation | movement of the row running apparatus which concerns on Embodiment 1 of this invention. It is a figure explaining the positional relationship of the vehicle which performs platooning which concerns on Embodiment 2 of this invention. It is an example of the image 101 imaged with the camera mounted in the back vehicle which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
Hereinafter, a row traveling device according to Embodiment 1 of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing the configuration of the row running apparatus 10. The convoy travel device is a device that is mounted on a rear vehicle (also referred to as a host vehicle or a succeeding vehicle) that follows a forward vehicle traveling in front and travels in a convoy, and the camera 11 that captures the front of the vehicle and the camera 11 captures the image. The number recognition unit 12 that recognizes the license plate of the forward vehicle 50 traveling ahead from the captured image and reads the number information described on the license plate, and the position and number information of the license plate in the captured image Based on the azimuth where the vehicle ahead is located, the azimuth to calculate the distance between the vehicle ahead and the vehicle behind, the distance calculator 13 and the travel of the vehicle behind based on the calculated azimuth and distance information, It is comprised from the control part 14 which maintains platooning with a front vehicle.

FIG. 2 is a diagram for explaining the positional relationship of vehicles that perform platooning, and shows a state in which the rear vehicle 1 and the front vehicle 50 form a platoon and perform platooning. As will be described later, a camera 11, a number recognition unit 12, an azimuth / distance calculation unit 13, and a control unit 14 are mounted on the rear vehicle 1. The camera 11 is installed at the front position of the rear vehicle 1 (for example, inside the front bumper), and images the front of the vehicle in the range of the field of view 20 of the camera 11.
The number plate 51 is a rear number plate attached to the front vehicle 50 and is attached to a predetermined position at the rear of the vehicle.
The number of the license plate 51 is a known number, and the mounting position of the license plate 51 at the rear of the vehicle 50 is also known.
Both the plate number of the number plate 3 and its mounting position are stored in a storage unit (not shown) of the number recognition unit 12 of the rear vehicle 1.
In the following description, it is assumed that the number plate 51 of the front vehicle is attached to the center position of the rear end surface of the vehicle. Further, it is assumed that the camera 11 of the rear vehicle 1 is installed at the center position of the vehicle front end surface.

FIG. 3 is an example of an image 100 captured by the camera 2 mounted on the rear vehicle 1. In the lower right of the image 100, an image 4 of the license plate 3 of the forward vehicle 10 traveling ahead is displayed.
Reference numeral 5 denotes the center position of the image 100, and reference numeral 7 denotes the center position of the number portion ("46-49" in the example of FIG. 3) of the displayed license plate.
6 is a vector indicating the positional relationship between the center position 5 of the image and the center position 7 of the number portion of the license plate. 8 is the width of the character (number), and 9 is the height of the character (number).
The license recognition unit 12 recognizes the license plate by performing image processing on the image 100 captured by the camera 2, and acquires the plate number of the license plate.
The number recognition unit 12 collates the acquired plate number with the plate number of the preceding vehicle 50 stored in the storage unit in advance, and confirms that the plate numbers match. If they do not match by collation, it is determined that the preceding vehicle is not a vehicle traveling in a platoon, and an abnormality report such as an alarm is issued.

  Note that a conventional number reading technique can be used as means for recognizing a license plate from an image acquired by a camera and acquiring a plate number. For example, a character reading device described in Patent Document 5 can read characters in an image captured from a close range, and details thereof are omitted here.

Next, the operation of the azimuth / distance calculator 13 will be described.
The azimuth / distance calculator 13 checks the vector 6 to determine whether the rear vehicle 1, which is the host vehicle on which the convoy travel device 10 is mounted, is on the left side or the right side of the front vehicle 50. That is, when the direction of the vector 6 is the right direction, the rear vehicle 1 that is the host vehicle travels on the right side with respect to the vehicle central axis of the front vehicle 50, and the direction of the vector 6 is the left direction. It can be seen that the rear vehicle 1 is traveling on the right side with respect to the vehicle central axis of the front vehicle 50. Further, the amount of deviation of the forward vehicle 50 from the vehicle center axis can be acquired from the length of the vector 6.
In this way, the azimuth and distance calculation unit 13 can recognize the directional relationship with the forward vehicle 50.
Note that the recognition of this directional relationship is based on the premise that the license plate 51 is provided at the center position of the front vehicle 50 and the camera 11 is installed at the center of the rear vehicle 1 as described above. By storing the position 51 and the position of the camera 11 in advance, the azimuth / distance calculation unit 13 can recognize the directional relationship with the forward vehicle 50 even when the camera 51 is installed at another position. it can.

Further, the azimuth / distance calculation unit 13 can estimate the distance from the preceding vehicle 50 based on the character width 8 and the character height 9.
This is because the size of the plate number of the license plate 51 is known, so that the size of the plate number can be converted into a distance using the number of pixels of the CCD of the camera 11, the size, the focal length of the camera, and the like.
Even in the case of an arbitrary vehicle other than the plate number stored in advance, the size of the license plate and the plate number are stipulated in the standard in principle. The distance from the preceding vehicle 50 can be estimated based on the width 8 and the character height 9.
In this way, the azimuth / distance calculation unit 13 can acquire the distance and azimuth between the front vehicle 50 and the rear vehicle 1 of the host vehicle based on the image in which the license plate of the vehicle traveling ahead is recognized. In this way, the rear vehicle 1 can obtain control information necessary for platooning.

Next, the control unit 14 controls the vehicle based on the direction and distance information acquired by the direction and distance calculation unit 13.
For example, if the vehicle 1 is traveling on the right side beyond the allowable range with respect to the preceding vehicle 50, the rear vehicle 1 performs steering wheel control and vehicle speed control, and the leftward traveling direction is left according to the distance between the current traveling speed and the preceding vehicle 50. Control the vehicle, such as turning it in the direction, and maintain platooning. If the heading is within the allowable range, the direction control is not performed and the row running is maintained.
Further, when the distance from the preceding vehicle 50 is too far, the speed is increased so as to be within a predetermined distance range, and the row running is maintained. Further, if the distance is too close to the preceding vehicle 50, there is a danger of a collision, so the speed is reduced so that the vehicle falls within a predetermined distance range, and the platooning is maintained.

FIG. 4 is a flowchart showing an example of the operation of the row running apparatus 10 described above.
The convoy travel device 10 of the rear vehicle 1 that performs the convoy travel captures an image of the front with the mounted camera 11 (step S01). The number recognizing unit 12 acquires image data from the camera 11, recognizes the number plate by predetermined image processing based on the image data, and acquires a plate number (S02). The number recognizing unit 12 compares the plate number of the preceding vehicle 50 stored in advance (S03), determines whether or not the vehicle traveling in front is a vehicle prior to platooning (S04), and different. If it is a vehicle, an abnormality report such as an alarm is issued (S05). Next, the azimuth / distance calculation unit 13 estimates the azimuth of the front vehicle 50 with respect to the host vehicle (rear vehicle 1) based on the location of the center position of the plate number of the license plate in the entire image (S06). The azimuth and distance calculation unit 13 determines whether or not the estimated azimuth is within a predetermined allowable range (S07). If the vehicle is traveling on the right side or the left side beyond the allowable range, The direction of the host vehicle is controlled so that the vehicle travels behind the front vehicle 50, and a warning of danger is issued when the platooning cannot be maintained (S08). Further, the azimuth / distance calculation unit 13 estimates the distance from the preceding vehicle 50 from the size of the plate number (S09). The azimuth / distance calculation unit 13 determines whether or not the distance is within the allowable range (S10). If the distance is not within the allowable range, the control unit 14 is instructed to adjust the speed and is dangerous when there is a risk of collision. Is issued (S11).

  As described above, the convoy travel apparatus 10 according to the first embodiment includes the camera 11, the number recognition unit 12, the azimuth / distance calculation unit 13, and the control unit 14, and the front in the image captured by the camera 11. Based on the position of the license plate of the vehicle and the size of the plate number of the license plate, the azimuth and distance from the preceding vehicle are obtained. Then, by controlling the vehicle according to the acquired azimuth and distance, the platooning is maintained by traveling behind the front vehicle 50 by a predetermined distance.

  According to the row running apparatus according to the present embodiment, a dedicated communication system, a laser, or a dedicated apparatus for measuring the distance and azimuth with the vehicle traveling in front using ultrasonic waves is unnecessary, and the camera It is possible to carry out platooning with a simple configuration such as an arithmetic processing unit.

As another embodiment, the row running apparatus according to the present invention may be mounted on a general vehicle that is not a vehicle that runs in a row. Since the distance and azimuth to the vehicle traveling ahead are known, it is effective for preventing rear-end collision and driving assistance. In this case as well, as described above, the “number plate” of the vehicle ahead of the vehicle is imaged from the host vehicle, which is a general vehicle, the number plate is automatically identified, and the distance is determined from the size of the letters and numbers. It recognizes and estimates the direction from the own vehicle to the preceding vehicle from the position of the license plate in the captured image.
Regarding the distance, the size of the letters on the license plate is specified, so there is no change depending on the vehicle, and the size of the captured characters is basically reduced in proportion to the distance of the vehicle, It is possible to know the distance between the host vehicle and the imaged vehicle by measuring the distance between the size of the character or the like and the vehicle in advance or by calculating using the lens and the pixel of the image sensor. With regard to the direction, if the mounting direction of the imaging device with the host vehicle is measured in advance, the orientation relationship between the captured vehicle and the host vehicle is recognized by recognizing which position on the image sensor the license plate is imaged. Can know. For example, when the camera is in front of the vehicle, it can be recognized that the image is in front of the camera if it is captured in the center of the vehicle, and that it is in front of the right if it is captured by the right.
As a result of recognizing the preceding vehicle in this way, if a distance approaches and there is a danger of a collision, an alarm is sounded or a brake is applied, thereby preventing rear-end collision and driving assistance.

  In the present embodiment, the row running by two vehicles has been described, but the same can be applied to the row running by three or more vehicles. In addition, the distance information is acquired based on the plate number. However, the distance information may be acquired based on the size of the number plate in the image. . In addition, the camera in the embodiment is an example of an imaging device, and may be a video device that captures a moving image.

Furthermore, the relationship between the acquired azimuth and distance may be recorded in time series. By analyzing the azimuth and distance recorded in time series, it is possible to recognize how the azimuth relation and distance relation between the preceding vehicle and the host vehicle are changing.
Since the relationship between the azimuth and the distance can be recognized for each imaging interval of the camera, the information on the azimuth and the distance can be obtained earlier by shortening the imaging interval, and the platooning can be stably performed.

Embodiment 2. FIG.
In the first embodiment, the distance is estimated based on the character width 8 and the character height 9 after image processing of the plate number of the preceding vehicle traveling straight on the straight road. In the recognition of letters and numbers, the change in the size of letters and numbers on the license plate was recognized by measuring the size of individual letters and numbers.

  FIG. 5 is a diagram for explaining the positional relationship of vehicles that perform platooning, and illustrates a state in which the rear vehicle 1 and the front vehicle 50 form a platoon and perform platooning. In addition, the same number is attached | subjected to the same structure as Embodiment 1, and the description is abbreviate | omitted. In FIG. 5, the front vehicle 50 faces the vehicle traveling direction to the right front with respect to the vehicle traveling direction of the rear vehicle 1.

FIG. 6 is an example of an image 101 captured by the camera 11 mounted on the rear vehicle according to the second embodiment.
As a result of the steering operation of the front vehicle 50 in the right direction, in the state where the traveling direction of the rear vehicle 1 and the traveling direction of the front vehicle 50 do not coincide with each other, the size of each number of the plate number of the captured image varies. Arise.
In the figure, 9b is the height of the character at the right end of the plate number ("9"), and 9c is the height of the character at the left end of the plate number ("4"). 8b is the width of the character of the plate number (“4649”). Thus, the height of the rightmost number and the leftmost number are different, and in the example of FIG. 6, the rightmost number (“9”) is captured larger than the leftmost number (“4”).

This means that the traveling direction of the front vehicle 50 is not parallel to the host vehicle (rear vehicle 1).
Further, it means that the forward vehicle 50 is traveling in a direction rotated clockwise with respect to the host vehicle.
That is, the traveling direction of the front vehicle 50 can be recognized from the image 101 captured by the camera 11 with reference to the traveling direction of the rear vehicle.

As another method for recognizing the traveling direction of the preceding vehicle 50, it is possible to estimate based on the character width 8.
The license plate is originally known for the vertical and horizontal width of the characters, but the horizontal width is shorter than the vertical width of the captured characters, indicating that the vehicle is not parallel. Based on this, it is possible to predict the difference in the traveling direction of the forward vehicle 50.

  As described above, the difference between the numbers (heights) of the numbers at the left and right ends of the plate number of the number plate of the preceding vehicle imaged by the camera 11 and the known vertical and horizontal widths of the characters are used. The azimuth / distance calculator 13 can recognize the traveling direction of the forward vehicle 50.

  The azimuth and distance calculation unit 13 outputs the acquired traveling direction of the preceding vehicle 50 to the control unit 14, and the control unit 14 controls the steering wheel so as to follow the traveling direction of the preceding vehicle 50, so carry out.

  The difference between the traveling directions of the front vehicle 50 and the rear vehicle 1 described in the second embodiment can be determined by analyzing the distance and direction in time series even in the row running apparatus of the first embodiment. . However, in the case of the first embodiment, since a plurality of time-series recognition results are necessary, there is a problem that it takes time to make a determination. On the other hand, in the second embodiment, it is possible to discriminate the difference in the traveling direction by one-time identification of the license plate, and the effect that the following operation can be performed in a short time is generated.

As described above, in the row running apparatus according to the present embodiment, it becomes possible to recognize the traveling direction of the vehicle traveling ahead based on the size of the plate number, and a more appropriate direction with a simple configuration such as a camera or a processing unit. Control becomes possible.
This is because the direction of the forward vehicle can be easily predicted at the next time by recognizing the heading of the forward vehicle. Instead of applying vehicle control to the current platooning state, This is because the vehicle can be controlled with respect to the state of the row running that occurs at the next time.

  As camera performance, an image resolution that can compare the difference in the size (height) of the plate number is necessary.

  1 Rear vehicle (own vehicle) 4 Captured image of license plate 7 Center position of numeric part of license plate 8 Width of character (number) in license plate image 9 Character in license plate image (number) Height, 10 platooning device, 11 camera, 12 number recognition unit, 13 heading, distance calculation unit, 14 control unit, 20 camera view, 50 forward vehicle, 51 (rear) number plate, 100, 101 Captured image.

Claims (3)

A row running device mounted on a rear vehicle that follows a front vehicle running in front and performs a row running,
An imaging unit for imaging a rear license plate of the front vehicle;
From the image captured by the imaging unit, a number recognition unit that recognizes the rear license plate and obtains characters or numbers described in the rear license plate;
Based on the position in the image of the rear license plate recognized by the number recognition unit, and the letters or numbers acquired by the number recognition unit, the direction in which the front vehicle is located relative to the rear vehicle, A direction for calculating the distance between the rear vehicle and the front vehicle, a distance calculation unit,
A convoy travel device comprising: a control unit that controls a travel operation of the rear vehicle so that the rear vehicle follows the front vehicle based on the direction and the distance. 2. The platooning according to claim 1, wherein the azimuth / distance calculation unit estimates the traveling direction of the front vehicle by comparing the size of each character or number described in the rear license plate. apparatus. An imaging unit for imaging a rear license plate of a vehicle traveling in front;
From the image captured by the imaging unit, a number recognition unit that recognizes the rear license plate and obtains characters or numbers described in the rear license plate;
Based on the position in the image of the rear license plate recognized by the number recognition unit and the letters or numbers acquired by the number recognition unit, the direction in which the front vehicle is located with respect to the own vehicle, A direction for calculating the distance to the vehicle ahead, a distance calculation unit,
A traffic accident prevention apparatus comprising: a control unit that determines whether there is a danger based on the direction and the distance, and performs a danger prevention process when there is a danger.

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