KR100991106B1 - System and method for recognizing license plate using camera module photographing front and back face of vehicle - Google Patents

Abstract

PURPOSE: A system and method for recognizing license plate using a camera module photographing front and back face of a vehicle are provided to increase the accuracy of recognizing a plate number by taking a picture of the front and back plate number of a vehicle. CONSTITUTION: A front camera module(100) takes a picture of the front plate number of vehicles. A back camera module(200) takes a picture of the back plate number of the vehicles. A controller(300) receives first and second signals and control front and back camera module. The controller recognizes first text and second texts and forms the plate number of the vehicles.

Description

Vehicle number recognition system and recognition method using front and back camera module {SYSTEM AND METHOD FOR RECOGNIZING LICENSE PLATE USING CAMERA MODULE PHOTOGRAPHING FRONT AND BACK FACE OF VEHICLE}

The present invention relates to a system and method for recognizing a vehicle number based on an image photographed using a camera module. More specifically, the vehicle number recognition system using the front and rear camera module that can complete the correct vehicle number by photographing the front and rear license plate of the vehicle by integrating the front and rear camera module and combining the recognized text with the photographed image; It is about a recognition method.

License Plate Recognition Device (LPR Device) is a device that recognizes a vehicle number as text by processing and analyzing an image taken by photographing a license plate of a vehicle with a camera.

However, the conventional license plate recognition device (LPR Device) is a method of photographing the front of the vehicle, and thus, when the front license plate is defaced, there is a problem in that the accuracy of recognition is reduced due to unrecognition or partial recognition of the license plate number.

In addition, when the vehicle enters and enters the roof line detector, the vehicle number recognizer operates to recognize the vehicle number. When the vehicle in front of the vehicle does not leave the vehicle, the license plate of the vehicle following it is covered and the vehicle number cannot be recognized. do.

Accordingly, there is a need for a recognition method capable of more accurately recognizing a vehicle number based on a photographed image along with the necessity of a vehicle number detector photographing both front and rear license plates as a vehicle number recognition object.

The present invention has been made by the necessity as described above, the first object of the present invention is a front and rear camera module that can increase the accuracy of vehicle number recognition by photographing and numbering both front and rear license plates of the vehicle with the front and rear camera module. To provide a vehicle number recognition system and a recognition method using.

A second object of the present invention is to provide an algorithm for vehicle number recognition in using respective texts recognized from front and rear license plates, and to provide a vehicle number recognition system using a front and rear camera module that can increase the accuracy of vehicle number recognition. And a recognition method.

In addition, an object of the present invention is to provide a configuration that can easily install the rear camera module to the front camera module installed in the existing site to use the existing front camera module as it is to reduce the cost of the system construction To provide a vehicle number recognition system and a recognition method using the front and rear camera module.

An object of the present invention as described above is to photograph the front license plate of the vehicle 10 based on the first entrance signal output from the first loop line detector 110 in response to the entry and exit of the vehicle 10. Front camera module 100; A rear camera module 200 photographing a rear license plate of the vehicle 10 based on a second entry signal output from the second loop line detector 210 after passing through the first loop line detector 110 of the vehicle 10; And controlling the front camera module 100 and the rear camera module 200 by receiving the first and second entrance signals, recognizing the first text based on the photographed front license plate, and the second text based on the photographed rear license plate. And a controller 300 for completing the vehicle number by combining the recognized first text and the recognized second text, wherein the controller 300 includes characters corresponding to each other between the first text and the second text. If the corresponding numbers are the same, select the same letter or the same number to complete the vehicle number, and if the letters or numbers are different, compare the letter-to-letter matching rate or the number-to-number matching rate, It can be achieved by providing a vehicle number recognition system using the front and rear camera module characterized in that the vehicle number is completed by selecting a number having a high matching rate.

The rear camera module 200 may be provided on one side of the support 130 supporting the front camera module 100, and photograph the opposite direction to the front camera module 100.

The front camera module 100 and the rear camera module 200 preferably include an infrared light emitting diode lamp 120.

Preferably, the second entrance signal is a trigger off signal of the second loop line detector 210.

The control unit 300 includes: detection signal processing means 330 for receiving first and second entrance signals and outputting control signals for controlling photographing of the front camera module 100 and the rear camera module 200; A still image recognition module 310 that recognizes the first and second texts as a still image of the photographed front license plate and the photographed rear license plate once; And a video recognition module 320 for recognizing first and second texts based on a plurality of frame images of the photographed front license plate and the photographed rear license plate.

The plurality of frame images may be 20 frames or more per second.

When only one text of the first text and the second text is recognized, the controller 300 may complete the vehicle number by selecting one recognized text.

The matching rate for each letter or the matching rate for each number may be percentage information represented by 0 to 100% in response to the degree of recognition of the letter or number by the controller.

The display unit 400 further includes a display unit 400 displaying the completed vehicle number, and the display unit 400 preferably displays a matching rate for each letter or a matching rate for each number in correspondence with letters or numbers.

On the other hand, an object of the present invention is another vehicle based on the first entry signal output from the first loop line detector 110 in response to the entry and exit lane 20 of the vehicle 10 in the front camera module 100 Photographing the front license plate (10) (S100); A first recognition step S200 of recognizing the first text based on the photographed front license plate; The rear camera module 200 photographs the rear license plate of the vehicle 10 based on the second entry signal output from the second loop line detector 210 after passing through the first loop line detector 110 of the vehicle 10. Step S300; A second recognition step S400 of recognizing the second text based on the photographed rear license plate; Comparing, by the controller 300, whether the recognized first text is identical to the recognized second text (S500); And a step (S600) of combining the recognized first text and the recognized second text by the control unit 300 to complete the vehicle number, by providing a vehicle number recognition method using a front and rear camera module. Can be achieved.

The first recognition step S200 and the second recognition step S400 of the control unit 300 may be a step in which the control unit 300 recognizes each text as a matching rate for each character or a matching rate for each number.

The first recognition step (S200) and the second recognition step (S400) of the control unit 300, when the control unit 300 does not recognize individual letters or individual numbers of each text, sets the matching rate for each character or the matching rate for each number. It is preferable to recognize it as 0%.

In the rear license plate photographing step (S300) of the rear camera module 200, the second entrance signal is preferably a trigger off signal of the second loop line detector 210.

Completing the vehicle number completion step (S600) of the control unit 300, the control unit 300 selects the same letter or the same number when the corresponding character or the corresponding number between the first text and the second text is the same (S610) ; And the control unit 300 completing the vehicle number as the selected letter or the selected number (S620).

Vehicle number completion step (S600) of the control unit 300, the control unit 300 compares the character-to-character matching rate or the number-specific matching rate when the letters corresponding to each other or the corresponding number between the first text and the second text is different; Step S630; Selecting, by the controller 300, a letter having a high matching rate for each letter or a number having a high matching rate for each number (S640); And the control unit 300 completing the vehicle number as the selected letter or the selected number (S650).

After the vehicle number completion step (S600) of the control unit 300, the display means 400 preferably further includes the step of displaying the completed vehicle number (S700).

According to one embodiment of the present invention as described above, the present invention can increase the accuracy of the vehicle number recognition by photographing both the front and rear license plate of the vehicle with the front and rear camera module and at the same time can operate any one camera module. Even if it is not present, the other camera module can be operated to provide flexibility of vehicle number recognition.

In addition, in using the respective texts recognized from the front and rear license plates, the accuracy of vehicle number recognition can be further improved by comparing matching rates between individual letters and individual numbers constituting the text.

In addition, the present invention provides a configuration that can easily install the rear camera module to the front camera module installed in the existing site to use the existing front camera module as it is to reduce the cost of system construction There is.

1 is a configuration diagram briefly showing the configuration of an embodiment of the present invention vehicle number recognition system,
2 is a perspective view and a partially enlarged view showing an embodiment of the present invention vehicle number recognition system,
3 to 6 are views showing the operating state of the camera module according to the entry and exit of the vehicle in order to explain the vehicle number recognition system of the present invention in order;
7 is a view sequentially showing an embodiment of the present invention vehicle number recognition method.

< Example >

<Vehicle Number Recognition System>

Figure 1 is a schematic diagram showing the configuration of an embodiment of the present invention vehicle number recognition system. As shown in FIG. 1, an embodiment of the present invention includes a front camera module 100 photographing a front license plate, a rear camera module 200 photographing a rear license plate, and a controller for recognizing text and completing a vehicle number ( 300).

In addition, the first loop line detector 110 and the second loop line outputting the entrance signal of the entry and exit lane 20 of the vehicle 10 to determine whether the front camera module 100 and the rear camera module 200 are photographed. The detector 210 is further provided.

In addition, the display means 400 for displaying the completed vehicle number may be further included. In particular, the controller 300 includes a detection signal processing means 330, a still image recognition module 310, and a video recognition module 320. Can be configured.

The vehicle number recognition system of the present invention will be described briefly, the first loop line detector 110 generates a first entry signal in response to the entry and exit of the vehicle 10 and receives the first entry signal. When the photographing control signal is output through the detection signal processing means 330, the front camera module 100 photographs the front license plate of the vehicle 10.

When the vehicle 10 enters the second loop line detector 210 after passing through the first loop line detector 110, the second loop line detector 210 generates a second entry signal, and the second loop signal is generated. The rear camera module 200 photographs the rear license plate through the detection signal processing means 330 receiving the entrance signal.

The first and second texts are recognized and recognized by image processing and analyzing the front license plate and the photographed rear license plate through the still image recognition module 310 and the video recognition module 320 of the controller 300. The vehicle number is completed by combining the two texts.

Looking at the configuration of the present embodiment in detail, the first loop line detector 110 and the second loop line detector 210 are buried in the entry and exit 20 to be spaced apart by a predetermined distance to allow the front and rear license plate photographing It serves to detect the vehicle 10.

The signal generated by the detection of the vehicle 10 may be divided into a trigger on signal generated when the upper part of the loop line enters and a trigger off signal generated when the upper part of the roof line leaves the loop line. In this embodiment, both the trigger on signal and the trigger off signal are used in some cases to secure the photographing viewing angle of the front and rear license plates.

The front camera module 100 is a configuration required for photographing the front license plate of the vehicle 10. The detection signal processing means 330 receiving the first entry signal from the first loop line detector 110 outputs a control signal to start capturing and transmits the captured image to the controller 300. The front camera module 100 is a digital CCD (Charge-Coupled Device) camera capable of shooting a still image or a video of a plurality of frames, a network camera capable of TCP / IP networking is preferable.

Shooting through the front camera module 100 is performed until the first text corresponding to the front license plate is recognized by the controller 300. However, even when the first text is not recognized, shooting ends when a predetermined time elapses.

The rear camera module 200 is a configuration required for photographing the rear license plate of the vehicle 10. The detection signal processing means 330, which receives the second entry signal from the second loop line detector 210, outputs a control signal to start capturing and transmits the captured image to the controller 300. The rear camera module 200 also uses a digital CCD (Charge-Coupled Device) camera capable of capturing still images or video of a plurality of frames, and the network camera capable of TCP / IP networking is the same as the front camera module 100. .

Shooting through the rear camera module 200 is performed until the second text corresponding to the rear license plate is recognized by the controller 300. However, even when the second text is not recognized, shooting is terminated after a predetermined time is the same as that of the front camera module 100.

The controller 300 receives the captured images of the front license plate and the rear license plate from the front camera module 100 and the rear camera module 200 to recognize the first and second texts, and based on the recognized first and second texts, the vehicle number. To complete.

In particular, when the first and second texts are the same, the number and the number of one text are selected to complete the vehicle number. The vehicle number is completed by selecting letters with high matching rate or numbers with high matching rate.

The control unit 300 recognizes the first and second texts with a still image photographed once for accurate vehicle number completion through text recognition and comparison and comparison of character matching rates or numerical matching rates. In addition, the video recognition module 320 may recognize the first and second texts based on a plurality of frame images of the photographed front license plate and the photographed rear license plate.

The still image recognition module 310 and the video recognition module 320 may be configured as a computer having a predetermined program embedded therein and capable of image processing and image analysis.

In addition, the control unit 300 receives the first and second entry signals from each of the camera modules 100 and 200 and detects signal processing means 330 to output a control signal for controlling the shooting of each camera module 100 and 200. For this purpose, a separate computer in which the vehicle detection program is built may be further provided.

Figure 2 is a perspective view and partially enlarged view showing an embodiment of the present invention vehicle number recognition system. As shown in FIG. 2, the first loop line detector 110 and the second loop line detector 210 are fixed on the entry / exit lane 20 to detect the vehicle 10 entering the entry / exit lane 20. Buried a distance away. In addition, the support 130 is positioned at the left side of the entry / exit lane 20 in the traveling direction to support the first camera module 100, and the second camera module 200 is provided at one side of the support 130.

In addition, the front camera module 100 includes a plurality of infrared light emitting diode (LED) lamps 120 under the camera lens for night photographing, and the first loop line detector 110 to photograph the front license plate. The surroundings are set within the photographing viewing angle. In addition, the infrared light emitting diode lamp 120 may be provided with a momentary lighting device (strobe, not shown) for irradiating infrared light at the moment of photographing the vehicle 10.

Like the front camera module 100, the rear camera module 200 is provided with a plurality of light emitting diode lamps 220 for lighting under the camera lens, and is opposite to the front camera module 100 to photograph the rear license plate. Heading in the direction. The plurality of light emitting diode lamps 220 are infrared light emitting diode lamps 220, and a momentary lighting device (strobe, not shown) may be provided as the front camera module 100 is the same.

3 to 6 are views illustrating the operating states of the camera modules 100 and 200 according to the entry and exit lane 20 of the vehicle 10 in order to explain the vehicle number recognition system of the present invention. 3 to 6, the operating states of the camera modules 100 and 200 according to the entry and exit lane 20 of the vehicle 10 will be described.

First, as shown in FIG. 3, when the vehicle 10 is positioned above the first loop line detector 110, the front camera module 100 photographs the front license plate of the vehicle 10. Of course, although not shown in Figure 3, through the detection signal processing means 330 of the control unit 300 receives the detection signal of the vehicle 10 of the first loop line detector 110 and receives the trigger on signal that is the first entry signal It outputs and photographs the front license plate in the photographing viewing angle A.

Afterwards, as shown in FIG. 4, when the vehicle 10 leaves the first loop line detector 110, photographing is terminated. In addition, the end of the recording of the front camera module 100 may be a time limit to end the shooting by the appropriate time limit, but the control unit 300 processes the front license plate image received from the front camera module 100, It is common to end by analyzing and acquiring a high recognition rate license number text.

As shown in FIG. 5, when the vehicle 10 is positioned above the second loop line detector 210, the rear camera module 200 is ready to be photographed. In the photographing standby state, for example, if an illumination for photographing is required, the infrared light emitting diode lamp 220 may be turned on.

Finally, as shown in FIG. 6, when the vehicle 10 leaves the second loop line detector 210, the rear camera module 200 photographs the rear license plate. Although not shown in FIG. 6, the detection signal processing means 330 of the controller 300 receives the detection signal of the vehicle 10 of the second loop line detector 210 and outputs a trigger off signal that is the second entry signal. To photograph the rear license plate in the photographing viewing angle (A).

<Vehicle Number Recognition Method>

7 is a view sequentially showing an embodiment of the present invention vehicle number recognition method. Referring to FIG. 7, first of all, the front camera module 100 is based on the first entrance signal output from the first loop line detector 110 in response to the entry and exit of the vehicle 10. Take a picture of the front license plate (S100).

Next, the control unit 300 recognizes the first text based on the photographed front license plate (S200).

Next, after the rear camera module 200 passes the first loop line detector 110 of the vehicle 10, the rear camera module 200 displays the rear license plate of the vehicle 10 based on the second entry signal output from the second loop line detector 210. Shoot (S300).

Next, the controller 300 recognizes the second text based on the photographed rear license plate (S400).

Next, the controller 300 compares whether the recognized first text is the same as the recognized second text (S500).

Finally, the control unit 300 completes the vehicle number by combining the recognized first text and the recognized second text (S600), and the vehicle number recognition method using the front and rear camera module is performed.

Here, in the first recognition step (S200) and the second recognition step (S400) of the control unit 300, the control unit 300 recognizes each text as a character matching rate or a number matching rate, and the control unit 300 each When the individual letters or numbers of the text are not recognized, it is preferable to recognize the matching rate for each character or the matching rate for each number as 0% and still use the matching rate comparison target.

In addition, in the rear license plate photographing step (S300) of the rear camera module 200, the second entrance signal is detected by the detection signal processing means of the control unit 300 as the vehicle 10 leaves the second loop line detector 210 ( 330 is a trigger off signal to be output.

In particular, the vehicle number completion step S600 of the control unit 300 selects the same character or the same number when the control unit 300 corresponds to the same text or the corresponding number between the first text and the second text (S610). The vehicle number recognition method using the front and rear camera modules may be performed by the controller 300 completing the vehicle number with the selected letter or the selected number (S620).

On the other hand, the vehicle number completion step (S600) of the control unit 300 compares the matching rate for each letter or the matching rate for each number if the control unit 300 has different characters or corresponding numbers between the first text and the second text. (S630), a letter having a high matching rate for each letter or a number having a high matching rate for each number is selected (S640). In addition, the vehicle number recognition method using the front and rear camera modules may be performed by the controller 300 completing the vehicle number with the selected letter or the selected number (S650).

An example of completing a vehicle number by applying a vehicle number recognition method using a front and rear camera module is shown in Table 1 below. Marked with x in Table 1 is an unrecognized letter or number with a matching rate of 0%.

Front camera recognition value

Rear camera recognition value
Completed vehicle number
Remarks
Seoulxx

Seoul 21xx2752
Seoul 21M2727
Complete by combining
Unrecognized

Seoul21ner2752
Seoul21ner2752
Rear camera recognition value
Seoul21ner2752

Seoul21ner2752
Seoul21ner2752
Complete with match
Seoul 21M2727
(Mer Matching Rate: 70%)

Seoul21ner2752
(Your matching rate: 85%)
Seoul21ner2752
Completed with rear camera recognition value with high matching rate for each character

On the other hand, after the vehicle number completion step (S600) of the control unit 300 by the display means 400 displays the completed vehicle number (S700) to inform the user of the recognized vehicle number to the system. Of course, the display means 400 may display the first and second texts recognized by each of the front and rear camera modules 100 and 200 in addition to the completed vehicle number, and in this case, display the character matching ratio and the numerical matching ratio together. can do.

A: shooting viewing angle
10: vehicle
20: by train
100: front camera module
110: first loop line detector
120: infrared light emitting diode lamp
130: support
200: rear camera module
210: second loop wire detector
220: infrared light emitting diode lamp
300: control unit
310: still image recognition module
320: video recognition module
400: display means

Claims (16)

A front camera module (100) for photographing the front license plate of the vehicle (10) based on a first entrance signal output from the first loop line detector (110) in response to entry of the vehicle (10) into and out of the lane;
A rear camera module photographing a rear license plate of the vehicle 10 based on a second entry signal output from the second loop line detector 210 after passing through the first loop line detector 110 of the vehicle 10 ( 200); And
Receives the first and second entrance signals to control the front camera module 100 and the rear camera module 200, recognizes a first text based on the photographed front license plate and based on the photographed rear license plate. And a controller 300 that recognizes a second text and completes a vehicle number by combining the recognized first text and the recognized second text. The controller 300 includes:
Detection signal processing means (330) for receiving the first and second entrance signals and outputting control signals for controlling photographing of the front camera module (100) and the rear camera module (200);
A still image recognition module 310 for recognizing the first and second texts as a still image of the photographed front license plate and the photographed rear license plate once; And
And a video recognition module 320 that recognizes the first and second texts based on a plurality of frame images of the photographed front license plate and the photographed rear license plate.
The controller 300 completes the vehicle number by selecting the same letter or the same number when the letters or the corresponding numbers are the same between the first text and the second text, and
When the letters or the numbers are different from each other by comparing the letter-to-letter matching rate or the number-by-number matching rate by selecting the letter having a high letter-to-letter matching rate or the number of the number-matching rate is completed by completing the vehicle number Vehicle number recognition system using a front and rear camera module.
The method of claim 1,
The rear camera module 200 is provided on one side of the support 130 for supporting the front camera module 100, the front and rear camera module, characterized in that to shoot the opposite direction to the front camera module 100 Vehicle number recognition system used.
The method of claim 1,
The front camera module (100) and the rear camera module (200) is a vehicle number recognition system using a front and rear camera module, characterized in that it comprises an infrared light emitting diode lamp (120).
The method of claim 1,
The second entry signal is a vehicle number recognition system using a front and rear camera module, characterized in that the trigger off signal of the second loop line detector (210).
delete The method of claim 1,
And a plurality of frame images are 20 frames or more per second.
The method of claim 1,
When the controller 300 recognizes only one of the first text and the second text, the controller 300 selects the recognized text to complete the vehicle number. Number recognition system.
The method of claim 1,
The letter-to-letter matching rate or the number-to-number matching rate is the percentage information represented by the controller in the range of 0 to 100% corresponding to the degree of recognition of the letters or numbers.
The method of claim 1,
It further comprises a display means 400, the completed vehicle number is displayed,
The display means (400) is a vehicle number recognition system using a front and rear camera module, characterized in that the matching rate for each letter or the matching rate for each number is displayed corresponding to the letter or the number.
The front camera module 100 photographs the front license plate of the vehicle 10 based on the first entrance signal output from the first loop line detector 110 in response to the entry and exit of the vehicle 10. Step S100;
A first recognition step (S200) of the control unit 300 recognizing the first text based on a still image of the photographed front license plate once by the video recognition module 320 that recognizes the first text;
The rear license plate of the vehicle 10 based on the second entry signal output from the second loop line detector 210 after the rear camera module 200 passes the first loop line detector 110 of the vehicle 10. Photographing the step (S300);
A second recognition step (S400) of recognizing the second text based on a still image of the photographed rear license plate once by the video recognition module 320 by the controller 300 to recognize the second text;
Comparing, by the controller 300, whether the recognized first text is identical to the recognized second text in a video recognition module 320 recognizing first and second texts (S500); And
Comprising: in the video recognition module 320 for recognizing the first and second text, the control unit 300 completes the vehicle number by combining the recognized first text and the recognized second text (S600); Vehicle number recognition method using the front and rear camera module, characterized in that.
The method of claim 10,
The first recognition step (S200) and the second recognition step (S400) of the control unit 300,
And the control unit 300 recognizes each text as a matching rate for each character or a matching rate for each number.
12. The method of claim 11,
The first recognition step (S200) and the second recognition step (S400) of the control unit 300,
Recognizing the vehicle number using the front and rear camera module, the controller 300 recognizes the matching rate for each letter or the matching rate for each number as 0% when the individual letter or the individual number of each text is not recognized. Way.
The method of claim 10,
In the rear license plate photographing step (S300) of the rear camera module 200,
The second entry signal is a vehicle number recognition method using a front and rear camera module, characterized in that the trigger off signal of the second loop line detector (210).
The method of claim 10,
Vehicle number completion step (S600) of the control unit 300,
Selecting, by the controller 300, the same letter or the same number when the letters or the corresponding numbers are the same between the first text and the second text; And
And the control unit 300 completing the vehicle number as the selected letter or the selected number (S620).
The method of claim 10,
Vehicle number completion step (S600) of the control unit 300,
Comparing, by the controller 300, a matching rate for each character or a matching rate for each number when the corresponding characters or the corresponding numbers are different between the first text and the second text (S630);
Selecting, by the controller 300, a letter having a high matching rate for each letter or a number having a high matching rate for each number (S640); And
The control unit 300 completes the vehicle number as the selected character or the selected number (S650); Vehicle number recognition method using a front and rear camera module, characterized in that it comprises a.
The method of claim 10,
After the vehicle number completion step (S600) of the control unit 300,
Vehicle number recognition method using the front and rear camera module, characterized in that the display means further comprises the step (S700) of displaying the completed vehicle number.

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