JPH02194498A - Car number plate detector - Google Patents

Abstract

PURPOSE:To surely extract a frame independently of the contrast between a number plate and its surrounding area by extracting the frame based on each digit position of numeral information of the number plate. CONSTITUTION:A numeral information processing means 14 fetches vehicle information from an image pickup means, segments the numeral information in the number plate information and specifies the digit position, and an identification mark processing means 15 specifies the digit information of the number plate information. A digit specifying means 16 specifies the digit of the numeral information in the number plate information based on the result of processing of the numeral information processing means 14 and the processing result of the identification mark processing means 15 and a plate frame extraction means 17 executes the extraction of the frame of the number plate based on the result of specification of the digit specifying means. Thus, the number plate area is surely segmented and the detector contributes to the practical execution of the vehicle management.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a vehicle license plate detection device.

(Prior art) In recent years, TV cameras,
Width axis management systems using computers and the like are being put into practical use.

A vehicle license plate detection device is known as one of the devices used in such a vehicle management system.

This vehicle license plate detection device uses a TV camera to image an area including the license plate NP of, for example, a small passenger car as shown in FIG. - Image processing was used to extract the frame information of the license plate NI'' and its position was specified.

However, in the case of the conventional device mentioned above, when cutting out the frame of the rectangular license plate NP, the full line I-1 of the frame is cut out in one cut. Since the position of the vertical line L2 is determined by image processing, for example, if the two contrasts of the license plate NP and the back part of - are less than or equal to 1,
Groove line 11. There was a problem in that the vertical line 12 was not detected well (incorrectly), and as a result, the frame information of the license plate N1 could not be cut out C'.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and it is possible to reliably extract the number play 1 to area, contributing to the feasibility of vehicle management. One of our objectives is to provide an automatic license plate detection device.

[Structure of the Invention] (Means for Solving the Problems) Vehicle number play of the present invention 1. Detection fee is a numerical report that fTf the number of digits of at least one finger, and the most accurate information of this numerical information. digit identification information for identifying numbers other than the largest digit is arranged in pre-standardized positions. A numerical information processing means that captures vehicle information including image and 7j number plate information, extracts numerical information from the license plate information () and (line position identification), and extracts the numerical information from the license plate information. Identification of digit identification information 4''<-r The identification mark processing means 4''<-r specifies the digits of the numerical information by 43 in the license plate information based on the processing results of the numerical information processing means r9 and the processing results of the identification mark processing means. The characteristic identification means extracts digits to number play 1 based on the identification result of this digit identification means (-1
It has a digit extraction means.

(for production) The operation of the apparatus having the above configuration will be explained below.

The imaging means of this device is one of the poonpa plates of the vehicle.
The n area is imaged as an Iki image, and at least one line of (numeric information having a line number and (line identification information for identifying the maximum digit or the number of digits other than the maximum digit) of this numerical information is placed in a pre-standardized position. Request vehicle information including license plate information.

The numerical information processing unit 1'2 takes in the vehicle information from the decoy image hand fQ, extracts the numerical information from the dog par plate information, and specifies the (t+ position).

The identification mark processing means specifies the (line identification information) of the license plate information.

Further, the identification mark processing means specifies the remaining digit identification information of the license plate information. The digit specifying means specifies the digit of the numerical information in the license plate information based on the processing result of the numerical information processing means and the processing result of the identification mark processing means.

The plate frame extraction means executes frame extraction of the uncovered number route based on the identification result of the village i identification means.

(Example) Examples of the present invention will be described in detail below.

The vehicle license plate detection device 1 shown in FIG. D conversion, memory, D/A
An information processing means 3 that performs each process of conversion, an image monitor 4 that displays the processing of this information processing means 3, a terminal, and an image monitor 4 that takes in image information from the information processing means 3 and processes a license plate N.
It has a vehicle information processing means 5 which performs frame output processing of P and processing of timing signals to the flash 6.

The information processing means 3 includes an A/D converter 7 which A/D converts the image information from the TV camera 2 and outputs it as digitalized vehicle information; The image memory 8 to be stored and the output of this image memory 8 are D/'A converted and li1! i-image～Send to 24 D/
A converter 9 is provided.

The vehicle information processing means 5 has a configuration shown in FIG. 2.

That is, an interface 10 that sends and receives information to and from the image memory 8, a CPU 11 connected to this interface 10, a program memory 12 that sends programs for controlling the operations of various parts to this CPU 11, and a binarization processing unit 13 that takes in the width axis information from the image memory 8 sent via the interface '10 and CI"Ull and processes it to convert it into binarized information;
A numerical information processing means 14 that processes numerical information (details will be described later) in the license plate information included in the vehicle information, and an identification mark (details will be described later) information as digit identification information also included in the license plate information. 1VPS-Identification mark processing means 15, said numerical information processing means 14 and identification mark processing means] 5. In each of the tJ8 Risung Dynasty, 1 a plate frame extracting means 17 for extracting a frame of license plate information from the identification result of the i identifying means 16; and the CPU 11.
The timing signal generating section 18 generates a timing signal for driving the flash under the control of the timing signal generating section 18 .

The numeric information processing means 14 determines how many layers of numeric information there is in the J-umper plate information, that is, a digit extraction unit 19 that performs digit extraction, and a technique that performs a calculation Q on the digit position of the numeric information to specify the digit position. It is equipped with a position performer section 20.

Here, one of the processing measures in this embodiment)-temper plate NP will be explained with reference to FIG. 3 (a) and FIG. 4. FIG. FIG. 4 shows one with four-digit numerical information, and FIG. 4 shows one with two-digit numerical information.

In cutting fields, as stipulated in the Six Automobile Laws, information on the rectangular frame of the license plate NP, uppercase numeric information (1 to 4 digits), and the rectangular number 1 indicating the 4 digits are used.
identification mark A, a second dot-shaped identification mark B that indicates 1 to 3 digits, hiragana information that is one of the information for identifying 11 Senguruma and Yuzu, kanji information that indicates the responsible Land Transport Bureau (for example, product ), type numerical information indicating the type of Nakawaku (for example, 52
)'s information (, soil, each size and arrangement are shown in Figure 3
a) As shown in FIG. 4, the dimensions (+nm) are standardized in advance.

In addition, the identification mark A is placed between the 15th 12th digit of the 4-digit numerical information and the last two digits, and the identification mark B is placed between the remaining 3 to 1 digits when the numerical information is 1 to 3 digits. It is designed to be placed in the area of

Furthermore, the number of digits of the numerical information of the license plate NP is 1
44 lines, and the zero width position in the X direction is standardized as follows. In other words, the first finger "
Width in the X direction of 6 pieces x 1 = 40.2nd finger 14'' position
2=95.3rd finger position X3=180.4th finger position X4=235.

Next, the operation of the device 1 having the above configuration will be explained.

This one? The TV camera 2 of the station 1 images an area including the non-permanent plate NP of the vehicle, and sends this to the A/D converter 7 as image information (width axis information).

This image information is converted into digital information by the A/D converter 7, and then sent to the image memory 8 and stored therein.

The CPU 11 of the vehicle information processing stage 1 5 takes in the vehicle information stored in the image memory 8 and converts it into a binarization processing section 13.
send to The binarization processing unit 13 converts the vehicle information into rOJ, for example.
, rlJ into binary information and sends the processing result to the CPU 11.

Next, the digit extraction unit 19 of the numerical information processing means 14 performs cp
The binarized width axle information sent from the Uil is taken in, and the numerical information 6, 4, 0, 2 in d3 is added to the license plate information in this axle information as shown in Figure 3 (b). Cut out.

Further, the digit position calculation unit 20 first extracts the position of the first digit (“6” in this embodiment) that exists in any number play] to NP based on the processing result of the digit extraction unit 19. .

Historically, the digit position calculation section 20 calculates the numeric information for the second finger [/1''
Extract the position of. The position X2 where this second finger numerical information exists is the width in the X direction of the first finger numerical information "6" X1 = 4
It can be obtained by performing the calculation of 2nd=XIX95/40, assuming that the second value is 0.

Similarly, the position X3 of the numeric information of the third finger is 3-X I
X 180/40.The position of numerical information X4 of the 4th village is X
It can be obtained by calculating a = XIX235/40.

The dripping terminal of the line position calculation unit 20 is
'li((Sent to the line specifying means 16.

By the way, in the case of the number bu no 1" NP that believes in the numerical information of 4 streets as shown in Fig. 3 <a>, the first identification mark 8 exists between the 2nd gakume and the 3rd technique H, and In the case of the number root NP having two-digit numerical information shown in Fig. 4, the second identification mark B exists in the third technique H and the fourth technique H, so the identification mark processing 1,000t915 is a binarization process. Information is fetched from the vehicle information section 13 into the number play I, and each identification mark △, B is identified by density hisdog sim calculation within a predetermined area determined by Y, and this processing result is sent to the CPU 11.
is sent to the digit specifying means 16.

The number plate N is based on each block of the digit position part 0 part 20 and the identification mark processing stage 15.
Specify the numerical information of P. In other words, it's fixed. Step 1
6 is at least the width of the numeric information of 1 technique H × 1 and 2 digits 1] When the information at position X2 exists and the information for the first identification mark exists, at this time The license plate NP is identified as having 4-digit numerical information, and this identification result is sent to the plate frame extraction means 1 via CP [Jli].
Send to 7.

In addition, ((i specifying means 16 determines that when the information of X1 and X2 and the information of the two second identification marks B are present, the license plate NP at this time is 2 This identification result is sent to the plate frame extraction means 17 via the CPU 11.

Based on the identification result of the digit identification means 16, the plate frame extraction means 17 selects J? shown in FIG. 3(a) or FIG. Next to standardized license plate information! l L 1
Then, the vertical line L2 is extracted.

The processing results of the above-mentioned one finger extraction section, two digit position calculating section 20, identification mark processing means 151 digit specifying means 16, and plate frame extraction means 17 are processed by the CPU'11. It is stored in the image memory 8 via the interface 10, and is converted into analog information by the D/A converter 9 and displayed on the screen of the image monitor 4.

will be displayed.

Further, the timing signal generating section 18 sends a timing signal for dark image to the control base of the CPU 11 to turn on the flash 6 for a predetermined period of time.

The present invention can be modified in many ways other than the embodiments described above.

For example, in the above embodiment, a case was explained in which the frame of a license plate for a small passenger car was extracted, but the dimensions are similarly specified for a large plate for a large automobile Φ, and the corresponding and Just do the proper processing. Furthermore, when the human characters are arranged diagonally, similar processing is possible as long as the inclination is not large.

It goes without saying that the recognition of the numbers 0 to 9 is performed using a known technique.

Furthermore, in addition to locating the numerical information mentioned above, we also use hiragana "
The frame extraction process may be executed after specifying "A".

[Effects of the Invention] According to the present invention described in detail above, since frame extraction is performed based on the position of each digit of the numerical information of the license plate, it is possible to extract frames regardless of the contrast between the license plate and the surrounding area. , it is possible to provide a vehicle license plate detection device that can actually extract frames in 61f and improve the efficiency of vehicle management.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the device of the present invention, Fig. 2 is a 10-step diagram of the Φ machine information processing means of the same device,
) is a dimensional explanatory diagram of an example of a license plate, and Figure 3 (b
) is an explanatory view of the license plate without showing the frame cut out state in J3, FIG. 4 is an explanatory view of dimensions of another example of Humbbert, and FIG. 5 is a plan view of an example of the license plate. 1...Vehicle license plate detection device, 2...TV
Camera, 14... Numerical information processing means, 15... Identification mark processing means, 16... Frame specifying means.

Claims (1)

[Scope of Claims] A license plate in which numerical information having at least one digit and digit identification information for identifying the maximum digit of this numerical information or the number of digits other than the maximum digit are arranged at pre-standardized positions. an imaging means for taking an image of vehicle information including information; a numerical information processing means for taking in the vehicle information including the license plate information imaged by the imaging means, and extracting the numerical information from the license plate information and specifying the digit position; identification mark processing means for specifying digit identification information in the license plate information; and identification mark processing means for specifying the digit identification information in the license plate information based on the processing results of the numeric information processing means and the processing results of the identification mark processing means. 1. A vehicle license plate detection device comprising: digit specifying means for extracting digits from a license plate based on the identification result of the digit specifying means.