CN1413861A - Automatic method for indentification of number plate of vehicle - Google Patents

Abstract

A method for automatically recognizing the license plate of vehicle features that the number recognition technique based on OCR technique and the image matching technique based on pattern recognition technique are combined to automatically register, authenticate and monitor the license plate, and alarm.

Description

Automatic license plate recognition method

Technical field

The present invention relates to a kind of automatic license plate recognition method, can register automatically, verify, monitor, report to the police, belong to the traffic engineering field the car plate of vehicle.

Background technology

Along with the high speed development of Chinese national economy, intelligent transportation has become the main direction of current transport administration development, and license plate recognition technology plays a part very important as the core of intelligent transportation.

Now, based on the number-plate number recognition technology of OCR technology comparative maturity, for example existing number-plate number recognition technology surpasses 95% to a discrimination of cleaning surfaces, complete car plate.But all there is a defective in existing number-plate number recognition technology, be exactly the quality that the accuracy of number-plate number identification depends critically upon car plate itself, only rely on and identify the number-plate number and discern car plate and understand and its use face is very limited because of being subjected to having a strong impact on of car plate quality.

On the other hand, for many practical application, only need whether the checking entrance and exit is that same car gets final product.For example in highroad toll collection system, only need to confirm whether the inlet and the vehicle that holds of visa card representative are that same vehicle can find whether the behavior of changing the card fee evasion is arranged, and do not need to know the real number-plate number.Therefore, under the correct prerequisite in car plate location, also can verify vehicle by the method for license plate image coupling.

Now, based on the growing maturation of the image matching technology of mode identification technology, and be applied in extensive fields.For example existing license plate image matching technique has comformability to difference such as the car plate size of taking, position, inclination, brightness, contrast ratios, and whether can pick out two license plate images quickly and efficiently is same image, and the coupling accuracy reaches more than 98%.For the relatively poor car plate of sole mass, the effect that adopts the license plate image matching technique to discern is fine.

Obviously, will combine based on the number-plate number recognition technology of OCR technology with based on the license plate image matching technique of mode identification technology and be used for car plate identification jointly and have better effect.But up to the present, also do not see document record and actual use that both are combined.

Summary of the invention

The object of the present invention is to provide a kind of car plate method of identification automatically, with existing based on the OCR technology number-plate number recognition technology and combine based on the license plate image matching technique of mode identification technology vehicle license plate registered automatically, verify, monitor, reported to the police, make serious dependence to the car plate sole mass broken away from the identification of vehicle license plate.

For realizing above-mentioned goal of the invention, the present invention adopts following technical scheme:

A kind of automatic license plate recognition method, the car plate means of identification that comprises controllable lighting lamp, camera lens, image capture module, memory device, communication module, computing module is installed at A place on the vehicle direct of travel and B place respectively, and on the road of the other direction opposite of car plate means of identification with the vehicle direct of travel mounting vehicle magnetic test coil, the detecting test of vehicle coil is connected with the car plate means of identification, and described method comprises the steps:

(1) the detecting test of vehicle coil at the A place detects signals of vehicles, triggers the A place car plate means of identification that is attached thereto;

(2) A place car plate means of identification is adjusted electronic shutter and exposure intensity according to ambient lighting, self-opening controllable lighting lamp light filling illumination at night;

(3) A place car plate means of identification is taken vehicle image;

(4) A place car plate means of identification positioning car memorial tablet is put;

(5) A place car plate means of identification utilizes the number-plate number recognition technology identification number-plate number;

(6) identify the number-plate number?

(7) if the number-plate number that preservation identifies is sent to its data in the car plate means of identification at B place; If for not, preserve the license plate image that step 4 obtains, corresponding data be sent in the car plate means of identification at B place;

(8) the detecting test of vehicle coil at B place detects signals of vehicles, triggers the B place car plate means of identification that is attached thereto;

(9) B place car plate means of identification is adjusted electronic shutter and exposure intensity according to ambient lighting, self-opening controllable lighting lamp light filling illumination at night;

(10) B place car plate means of identification is taken vehicle image;

(11) B place car plate means of identification positioning car memorial tablet is put;

(12) B place car plate means of identification utilizes the number-plate number recognition technology identification number-plate number;

(13) identify the number-plate number?

(14) if, it is compared with the number-plate number that the A place obtains, judge whether A, B place are same vehicle; If for not, preserve the license plate image that step 11 obtains, change next step over to;

(15) the car plate means of identification license plate image that utilizes license plate image that the license plate image matching technique sends step 7 and step 11 to obtain in B place mates, and judges whether A, B place are same vehicle.

In the step in the above-mentioned automatic license plate recognition method (7), number-plate number data and license plate image data are sent in the car plate means of identification at B place by computer network.

In the step in the above-mentioned automatic license plate recognition method (7), number-plate number data and license plate image data deposit in the visa card of vehicle, take the car plate means of identification use of B place for the B place voluntarily to by vehicle.

In the step in the above-mentioned automatic license plate recognition method (7), number-plate number data deposit the visa card towel of vehicle in, take the car plate means of identification use of B place for the B place voluntarily to by vehicle; The license plate image data are sent in the car plate means of identification at B place by computer network.

In the step in the above-mentioned automatic license plate recognition method (7), the license plate image data are converted to the license plate image characteristic data, and deposit in together in the visa card of vehicle with number-plate number data, take the car plate means of identification use of B place for the B place voluntarily to by vehicle.

Automatic license plate recognition method provided by the present invention will combine based on the number-plate number recognition technology of OCR technology with based on the license plate image matching technique of mode identification technology, not only can mate according to number-plate number recognition result, also can carry out the license plate image coupling according to license plate image, make serious dependence to the car plate sole mass is broken away from the identification of vehicle license plate, adapt to various environment, the recognition accuracy height, can be used on highroad toll collection system, city bayonet socket monitored control system, the overspeed of vehicle occasions such as system of deploying to ensure effective monitoring and control of illegal activities.

Description of drawings

Fig. 1 is the scheme drawing that utilizes the Vehicle License Plate Recognition System of this automatic license plate recognition method.

Fig. 2 is the diagram of circuit of automatic license plate recognition method of the present invention.

The specific embodiment

Below in conjunction with the drawings and specific embodiments automatic license plate recognition method of the present invention is further described.

Fig. 1 is the scheme drawing that utilizes the Vehicle License Plate Recognition System of this automatic license plate recognition method.Wherein A ' is the detecting test of vehicle coil at A place, and B ' is the detecting test of vehicle coil at B place.At A, B place the car plate means of identification is installed respectively.

Fig. 2 is the diagram of circuit of automatic license plate recognition method of the present invention.The particular content of this diagram of circuit has been described in detail in technical scheme.Just no longer repeated herein.

At first be that example describes automatic license plate recognition method of the present invention with the highroad toll collection system.In highroad toll collection system, the A place is inlet, the B place is outlet, going into, exporting the suitable distance mounting vehicle magnetic test coil in the place ahead, in entrance and exit the car plate means of identification that comprises controllable lighting lamp, camera lens, image capture module, memory device, communication module, computing module is installed, is gone into, the detecting test of vehicle coil in exit is connected with car plate means of identification accordingly.

When vehicle during near the entrance, the detecting test of vehicle coil of entrance detects signals of vehicles, triggers the entrance car plate means of identification that is attached thereto.Entrance car plate means of identification is at first adjusted electronic shutter and exposure intensity according to ambient lighting, and self-opening controllable lighting lamp light filling illumination at night is clear to guarantee the vehicle image of taking, and is convenient to identification.Entrance car plate means of identification is taken vehicle image, is put by its built-in algorithm of locating license plate of vehicle positioning car memorial tablet, utilizes the number-plate number recognition technology identification number-plate number based on the OCR technology again.If identify the number-plate number, just the number-plate number that identifies is write in the visa card (ticket) of vehicle, if do not identify the number-plate number, just preserve the license plate image that obtains, and it is sent in the car plate means of identification in exit.

After the detecting test of vehicle coil in exit detects signals of vehicles, trigger the exit car plate means of identification that is attached thereto.Exit car plate means of identification is adjusted electronic shutter and exposure intensity according to ambient lighting, and self-opening controllable lighting lamp light filling illumination at night is clear to guarantee the vehicle image of taking, and is convenient to identification.Exit car plate means of identification is taken vehicle image, is put by its built-in algorithm of locating license plate of vehicle positioning car memorial tablet, utilizes the number-plate number recognition technology identification number-plate number based on the OCR technology again.If identify the number-plate number, it is compared with the number-plate number in the visa card (ticket), judgement is gone into, whether the exit is same vehicle, if do not identify the number-plate number, just preserve the license plate image that exit car plate means of identification obtains, utilization is mated it license plate image with the acquisition of entrance car plate means of identification based on the license plate image matching technique of mode identification technology, and judgement is gone into, whether the exit is same vehicle.

Above-mentioned car plate means of identification comprises hardware devices such as controllable lighting lamp, camera lens, image capture module, memory device, communication module, computing module.These hardware devices all are existing ripe equipment, are easy to obtain on market, and for example the controllable lighting lamp can be the LED that emits white light, and image capture module can use the relevant devices in the existing digital camera, and memory device can use E²PROM, computing module can use digital signal processor, also can use micro controller system.The visa card of vehicle can be an IC-card, also can be magnetic card.Employed car plate location, characters on license plate cutting, Recognition of License Plate Characters, license plate image coupling scheduling algorithm can use existing ripe algorithm in the car plate identifying, have just repeated no more herein.

This automatic license plate recognition method also can be used in the bayonet socket monitored control system of city, deploys to ensure effective monitoring and control of illegal activities with realization, finds also to tackle the vehicle of escaping after violating the regulations or the accident.In the bayonet socket monitored control system of city, each main bayonet socket in the city is installed the car plate means of identification, in case finding to have vehicle peccancy or accident back escapes, be installed on the car plate means of identification that (is equivalent to the A place) herein and can identify the number-plate number or record license plate image, be sent to the system computer place, be sent on the car plate means of identification of each main bayonet socket by system computer again, when violating the regulations or vehicle when bayonet socket occurs, the car plate means of identification of this bayonet socket (being equivalent to the B place) is by the identification number-plate number or coupling license plate image, can find whether be violating the regulations or vehicle, by the reporting system computing machine, carry out uniform dispatching by system computer, can tackle vehicle violating the regulations or that escape in the accident back.

This automatic license plate recognition method can also be used in the system that deploys to ensure effective monitoring and control of illegal activities that exceeds the speed limit.The hypervelocity system of deploying to ensure effective monitoring and control of illegal activities is divided into overspeed detection system and two parts of vehicle intercepting system, and wherein the overspeed detection system finishes work such as speed of a motor vehicle detection, number-plate number identification, overspeed of vehicle judgement, over-speed vehicles record; The vehicle intercepting system carries out car plate identification to traffick, judges whether to be over-speed vehicles, so that over-speed vehicles is tackled.

The overspeed detection system comprises vehicle speed detector device and car plate means of identification (the car plate means of identification that is equivalent to the A place).After detecting overspeed of vehicle by vehicle speed detector device, the car plate means of identification identification number-plate number or record license plate image, be sent to the system computer place, be sent in the car plate means of identification (the car plate means of identification that is equivalent to the B place) in the vehicle intercepting system by system computer again, by the identification number-plate number or coupling license plate image, can find whether be over-speed vehicles, carry out uniform dispatching by system computer again, tackle.

When adopting above-mentioned automatic license plate recognition method, the data of A place car plate means of identification output comprise:

(1) number-plate number data: comprise the number-plate number and be used for the data that the number-plate number is mated, totally 64 bytes.

(2) license plate image data: be the license plate image of jpeg format, average 2K byte is less than the 3K byte.

(3) license plate image characteristic data: be 512 byte datas that comprise car plate picture principal character.

License plate image characteristic data is wherein formed by the license plate image data transfer.

For city bayonet socket monitored control system or the hypervelocity system that deploys to ensure effective monitoring and control of illegal activities, can utilize computer network directly to carry out data transmission.

For highroad toll collection system, above-mentioned number-plate number data can be stored in the visa card (ticket) of vehicle, take B place (exit) voluntarily to by vehicle, for the car plate means of identification use in B place (exit).

Above-mentioned license plate image data bulk is bigger, if the visa card internal memory of vehicle is bigger, can directly view data be deposited in the visa card, for the car plate means of identification use in B place (exit); If the visa card internal memory of vehicle is less, can adopt two schemes.A scheme is that the license plate image data are transmitted by computer network, but this needs A place (entrance) and B place (exit) can both obtain network support.Another scheme does not need network support, directly car plate picture feature data is deposited in the visa card.This scheme is little to the visa card request memory, but owing to utilize the picture feature data to carry out the license plate image coupling, effect slightly is worse than the license plate image matching effect that is directly undertaken by image.

Need to prove; particular case of the present invention is described in detail automatic license plate recognition method of the present invention; for a person skilled in the art, the various conspicuous change of under the situation of the spirit and scope that do not deviate from the method for the invention it being carried out is all within protection scope of the present invention.

Claims (5)

1. automatic license plate recognition method, the car plate means of identification that comprises controllable lighting lamp, camera lens, image capture module, memory device, communication module, computing module is installed at A place on the vehicle direct of travel and B place respectively, and on the road of the other direction opposite of car plate means of identification with the vehicle direct of travel mounting vehicle magnetic test coil, the detecting test of vehicle coil is connected with the car plate means of identification, and described method comprises the steps:

(1) the detecting test of vehicle coil at the A place detects signals of vehicles, triggers the A place car plate means of identification that is attached thereto;

(2) A place car plate means of identification is adjusted electronic shutter and exposure intensity according to ambient lighting, self-opening controllable lighting lamp light filling illumination at night;

(3) A place car plate means of identification is taken vehicle image;

(4) A place car plate means of identification positioning car memorial tablet is put;

(5) A place car plate means of identification utilizes the number-plate number recognition technology identification number-plate number;

(6) identify the number-plate number?

(7) if the number-plate number that preservation identifies is sent to its data in the car plate means of identification at B place; If for not, preserve the license plate image that step 4 obtains, corresponding data be sent in the car plate means of identification at B place;

(8) the detecting test of vehicle coil at B place detects signals of vehicles, triggers the B place car plate means of identification that is attached thereto;

(9) B place car plate means of identification is adjusted electronic shutter and exposure intensity according to ambient lighting, self-opening controllable lighting lamp light filling illumination at night;

(10) B place car plate means of identification is taken vehicle image;

(11) B place car plate means of identification positioning car memorial tablet is put;

(12) B place car plate means of identification utilizes the number-plate number recognition technology identification number-plate number;

(13) identify the number-plate number?

(14) if, it is compared with the number-plate number that the A place obtains, judge whether A, B place are same vehicle; If for not, preserve the license plate image that step 11 obtains, change next step over to;

(15) the car plate means of identification license plate image that utilizes license plate image that the license plate image matching technique sends step 7 and step 11 to obtain in B place mates, and judges whether A, B place are same vehicle.

2. number-plate number data and license plate image data are sent in the car plate means of identification at B place by computer network in the automatic license plate recognition method as claimed in claim 1, step wherein (7).

3. number-plate number data and license plate image data deposit in the visa card of vehicle in the automatic license plate recognition method as claimed in claim 1, step wherein (7), take the car plate means of identification use of B place for the B place voluntarily to by vehicle.

4. number-plate number data deposit in the visa card of vehicle in the automatic license plate recognition method as claimed in claim 1, step wherein (7), take the car plate means of identification use of B place for the B place voluntarily to by vehicle; The license plate image data are sent in the car plate means of identification at B place by computer network.

5. automatic license plate recognition method as claimed in claim 1, the license plate image data are converted to the license plate image characteristic data in the step wherein (7), and and number-plate number data deposit in together in the visa card of vehicle, take B place voluntarily to for the use of the car plate means of identification at B place by vehicle.

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