KR100266404B1 - Apparatus and method for detecting car - Google Patents

Abstract

PURPOSE: An apparatus and a method for detecting a car are provided to be capable of accurately capturing the image for recognizing a number plate by using a laser slit scanning. CONSTITUTION: A laser emission part(22) scans laser with a slit shape to a road under the control of a host computer(21). An image input(24) receives the laser of slit shape as an image through a camera(23). A laser detector(25) detects the laser slits from the image of the image input(24). A distance measuring part(26) measures the distances of respective points of the detected laser slits. A car/traffic information extractor(27) extracts car detection information and traffic information from the measured road information. A number plate recognizer(30) receives the extracted car detection information and traffic information to control a camera(28) for recognizing a number plate and pickup the image of the number plate, thereby recognizing the number plate image.

Description

Vehicle detection device and method

The present invention relates to a vehicle detection apparatus and method, and more particularly, to a vehicle detection apparatus and method that is effectively applied to the detection of the vehicle on the road and the vehicle type recognition device suitable for use in the road traffic control field.

As the modern industrial society develops, the congestion of road traffic due to the increase of vehicles is increasing. Therefore, the acquisition and control of traffic information for road traffic control has emerged as an important issue. The general traffic control information includes vehicle average speed, flow rate, traffic density, air volume, license plate recognition, etc. In order to do this, the detection of the vehicle is absolutely necessary.

The most basic and traditional vehicle detection device used to date is a loop detector that installs a detection sensor on a road. However, the loop detector has a disadvantage that the damage of the loop to the passage of the vehicle for a long time is serious, affected by climatic conditions, and difficult to install and maintain.

Therefore, recently, detectors of an image processing method using a video signal have been used to compensate for these shortcomings. A two-dimensional image processing method that processes only brightness values of a video signal has a problem that is sensitive to natural lighting.

In order to reduce the influence of natural lighting, a technology for detecting a vehicle through three-dimensional image information using distance information has been developed. The distance information is obtained by measuring and calculating the time until the radio wave is received by the radio wave after being reflected by the vehicle or the road. When described in detail with reference to the accompanying drawings, such a conventional vehicle detection apparatus as follows.

Figure 1 is an exemplary view showing the installation of a conventional vehicle detection device, Figure 2 is an internal configuration of the sensor in Figure 1, after emitting the radio wave as shown therein, after the radio wave reflected through the vehicle on the road It consists of a sensor 10 for receiving and detecting the vehicle, the sensor 10 includes a radio wave driving unit 11 for generating radio waves; A reflector 13 for reflecting the radio wave and outputting the radio wave to a vehicle on the road, and reflecting the radio wave reflected through the vehicle to the radio wave receiver 12; An arithmetic unit 14 for converting a time difference between light emission and light reception into a distance through radio waves inputted to the radio wave reception unit 12; Comprising a host computer 15 for the overall control of the sensor 10, the reflector 13 is composed of a mirror (M1) and polygon mirror (PM1). Hereinafter, the operation of the conventional vehicle detecting apparatus configured as described above will be described.

First, when the firing signal START is input from the calculating section 14 under the control of the host computer 15, the laser driver 11 launches radio waves. The emitted radio wave is reflected through the reflector 13 whose angle is controlled by the host computer 15 and scanned in a linear direction toward the vehicle traveling on the road.

The emitted radio wave is reflected by the road or the vehicle, reflected back through the reflector 13, and input to the radio wave receiver 12. The radio wave receiver 12 outputs a reception signal STOP to the calculator 14 when a radio wave is received. Therefore, the calculator 14 outputs a start point of the firing signal START and an input point of the reception signal STOP. Calculate and convert to distance.

The calculated distance information is synthesized into a distance image by the host computer 15 and used as information for identifying a detection position, extracting traffic volume information, and recognizing a vehicle type.

However, the conventional vehicle detection apparatus as described above uses a method of receiving a radio wave reflected from a road or a vehicle by firing an electric wave, so when the radio wave is emitted at an angle of about 45 ° or more, the reception is difficult, and thus it is impossible to use. In addition to the problem, since the position of the vehicle is severe at a distance of 45 degrees or less, there is a problem that it is difficult to acquire an image for license plate recognition.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus and method for detecting a vehicle by laser slit scanning which can accurately acquire an image for license plate recognition.

1 is an exemplary view showing the installation of a conventional vehicle detection device.

2 is an internal configuration diagram of a sensor in FIG. 1;

Figure 3 is a block diagram showing an embodiment of a vehicle detection apparatus according to the present invention.

FIG. 4 is a block diagram showing an embodiment of the laser light emitting unit in FIG. 3; FIG.

FIG. 5 is a block diagram showing another embodiment of the laser light emitting unit in FIG. 3; FIG.

Figure 6 is a flow chart showing a vehicle detection method according to the present invention.

7 is an exemplary view showing a laser slit scanned on a road.

8A to 8C are exemplary views of an image signal detected by the laser detector of FIG.

*** Description of the symbols for the main parts of the drawings ***

21: host computer 22: laser light emitting unit

23: vehicle detection camera 24: video input unit

25: laser detection unit 26: distance measuring unit

27: vehicle / traffic information extraction unit 28: license plate recognition camera

29: Central Traffic Information Department 30: License Plate Recognition Department

31: image acquisition unit 32: image processing unit

33: recognition result communication unit

First, the vehicle detecting apparatus for achieving the object of the present invention as described above comprises a laser light emitting unit for scanning the laser on the road in the form of a slit under the control of the host computer; An image input unit which receives the slit-shaped laser as an image through a vehicle detecting camera; A laser detector detecting a laser slit from an image of the image input unit; A distance measuring unit measuring a distance to each point of the detected laser slit; A vehicle / traffic information extraction unit for extracting vehicle detection information and traffic information from the measured distance information; After receiving vehicle detection information and traffic information extracted from the vehicle / traffic information extracting unit, the license plate recognition camera is controlled to acquire an image of the license plate, and the license plate is recognized by the image processing and output to the central traffic information unit. It is composed.

In addition, the vehicle detection method for achieving the object of the present invention as described above comprises a first step of filtering and receiving the initial image signal; A second step of removing noise of the video signal input in the first step and reinforcing an image of the slit region; Extracting a center point of the slit from the enhanced image of the second step through a weighted center of gravity method; A fourth step of determining whether a vehicle exists by checking a position of the slit center point; A fifth step of extracting the height and location information of the vehicle and driving the license plate recognition camera if the vehicle exists in the fourth step, and storing the slit information and returning to the first step if the vehicle does not exist; A sixth step of repeating the first to fifth steps until the vehicle passes completely; A seventh step of synthesizing the height information from the image obtained through the sixth step; The eighth step of calculating traffic volume information of the road using the data obtained in the seventh step and recognizing the vehicle type.

The vehicle detection apparatus and method according to the present invention as described above will be described in detail with reference to the accompanying drawings.

Figure 3 is a block diagram showing an embodiment of a vehicle detection apparatus according to the present invention, a laser light emitting unit for scanning the laser on the road in the form of a slit under the control of the host computer 21 as shown 22); An image input unit 24 which receives the slit-shaped laser as an image through the vehicle detecting camera 23; A laser detector 25 for detecting a laser slit from an image of the image input unit 24; A distance measuring unit 26 for measuring a distance to each point of the detected laser slit; A vehicle / traffic information extraction unit 27 for extracting vehicle detection information and traffic information from the measured distance information; After receiving the vehicle detection information and traffic information extracted from the vehicle / traffic information extraction unit 27, the license plate recognition camera 28 is controlled to acquire an image of the license plate, and the license plate is recognized through image processing to recognize the license plate. It consists of a license plate recognition unit 30 to output to 29, the license plate recognition unit 30 receives the vehicle detection signal from the vehicle / traffic information extraction unit 27 through the license plate recognition camera 28 An image acquisition unit 31 for acquiring license plate images; An image processor 32 which processes an image of the image acquisition unit 31 to recognize a license plate; And a recognition result communication unit 33 for outputting the traffic information, which is the output of the vehicle / traffic information extracting unit 27, and the output of the image processing unit 32, to the central traffic information unit 29.

FIG. 4 is a block diagram showing an embodiment of the laser light emitting unit 22. As shown in FIG. 4, a laser control unit for generating a laser from the laser driver 41 under the control of the host computer 21 is shown in FIG. 42); It consists of a cylindrical lens 43 which diffuses the laser in the form of a slit and scans it on the road. The cylindrical lens 43 of the host computer 21 as shown in FIG. It is also possible to diffuse the laser reflected through the mirror 52 in the form of a slit using the controlled rotating polygon mirror 51.

FIG. 6 is a flowchart illustrating a vehicle detecting method according to the present invention, and as shown therein, a first step S1 of receiving an initial image signal in a state in which there is no vehicle; A second step S2 of filtering the image input in the first step S1 through a camera filter; A third step S3 of removing noise of the filtered image and reinforcing an image corresponding to the slit region; A fourth step S4 of extracting a center point of the slit from the enhanced image through a weighted center of gravity method; A fifth step (S5) of checking the position of the slit center point; A sixth step S6 of determining whether a vehicle exists at the identified position; A seventh step (S7) of extracting the height and position information of the vehicle and driving the license plate recognition camera if the vehicle exists in the sixth step (S6); An eighth step S8 of storing slit information and returning to the first step S1 if the vehicle does not exist in the sixth step S6; A ninth step S9 of repeatedly performing the first to seventh steps S7 until the vehicle passes completely; A tenth step (S10) of synthesizing the height information from the image obtained through the ninth step (S9); The traffic volume information of the road is calculated using the data obtained in the tenth step S10, and the eleventh step S11 of recognizing the vehicle type is performed. Hereinafter, the operation process of the present invention as described above.

First, the laser light emitting unit 22 scans the laser on the road in the form of a slit under the control of the host computer 21. At this time, the laser of the slit type is a wavelength that is harmless to the driver of the vehicle, as shown in Fig. 7 is scanned on the vehicle on the road, when a large angle is scanned, the scattered laser light is more scattered laser light than reflection Reach the vehicle detection camera 23 through the filter. On the other hand, the vehicle detection camera 23 should use a camera having a structure sensitive to the infrared wavelength band of the non-visible region.

Since the image signal input through the vehicle detection camera 23 is weak, the image input unit 24 applies the image amplification algorithm to emphasize the noise removal and the infrared signal part, and then the laser detection unit 25 performs the weighted center of gravity method. Apply to detect the laser slit. In this case, the detected video signal is illustrated in the exemplary diagram of FIG. 8. 8A is an exemplary view showing a video signal detected when there is no vehicle, FIG. 8B is an exemplary view showing a video signal detected when a vehicle enters the road, and FIG. 8C is continuously detected after FIG. 8B. It is an exemplary view showing a video signal.

Meanwhile, the distance measuring unit 26 measures the distance of each laser slit detected as described above and outputs the distance to the vehicle / traffic information extraction unit 27. Accordingly, the vehicle / traffic information extractor 27 synthesizes the video signals detected differently according to whether the vehicle enters as described above, extracts the traffic volume information of the road, and extracts the height and location information of the vehicle. On the basis of this, the vehicle is recognized as a 3D image and the entry point can be recognized, so that the vehicle detection signal is output to the image acquisition unit 31 of the license plate recognition unit 30 to drive the license plate recognition camera 28. .

When the license plate recognition camera 28 is driven in this way, the license plate image is recognized by the image acquisition unit 31 and the image processing unit 32, the recognition result of the license plate and the vehicle / through the recognition result communication unit 33 Traffic information of the traffic information extraction unit 27 is output to the central traffic information unit 29.

As described above, the vehicle detecting apparatus and method according to the present invention have the effect of acquiring vehicle information and traffic information through a scattered laser beam by scanning a laser slit, thereby acquiring a license plate of a moving vehicle even at an angle greater than 45 °. In addition, since it can be applied to various angles, there is an effect that the convenience of application is increased without being restricted by the position selection of the license plate recognition camera.

Claims (5)

A laser light emitting unit which scans a laser on the road in the form of a slit under the control of a host computer; An image input unit which receives the slit-shaped laser as an image through a vehicle detecting camera; A laser detector detecting a laser slit from an image of the image input unit; A distance measuring unit measuring a distance to each point of the detected laser slit; A vehicle / traffic information extraction unit for extracting vehicle detection information and traffic information from the measured distance information; After receiving vehicle detection information and traffic information extracted from the vehicle / traffic information extracting unit, the license plate recognition camera is controlled to acquire an image of the license plate, and the license plate is recognized by the image processing and output to the central traffic information unit. Vehicle detecting device, characterized in that configured. The apparatus of claim 1, wherein the license plate recognition unit comprises: an image acquisition unit which receives a vehicle detection signal from the vehicle / traffic information extraction unit and acquires a license plate image through a license plate recognition camera; An image processor which processes an image of the image acquisition unit to recognize a license plate; And a recognition result communication unit configured to output the traffic information, which is the output of the vehicle / traffic information extraction unit, and the image processing unit, to the central traffic information unit. The laser light emitting device of claim 1, wherein the laser light emitter comprises: a laser controller configured to generate a laser from the laser driver under control of a host computer; And a cylindrical lens that diffuses the laser in the form of a slit and scans it on a road. The apparatus of claim 1 or 3, wherein the laser light emitting unit comprises: a laser controller for generating a laser from the laser driver under the control of a host computer; And a rotating polygon mirror configured to diffuse the laser reflected through the mirror in the form of a slit under the control of the host computer and scan it on a road. A first step of filtering and receiving an initial video signal; A second step of removing noise of the video signal input in the first step and reinforcing an image of the slit region; Extracting a center point of the slit from the enhanced image of the second step through a weighted center of gravity method; A fourth step of determining whether a vehicle exists by checking a position of the slit center point; A fifth step of extracting the height and location information of the vehicle and driving the license plate recognition camera if the vehicle exists in the fourth step, and storing the slit information and returning to the first step if the vehicle does not exist; A sixth step of repeating the first to fifth steps until the vehicle passes completely; A seventh step of synthesizing the height information from the image obtained through the sixth step; And an eighth step of calculating traffic volume information on the road using the data obtained in the seventh step and recognizing the vehicle type.