JPH0447490A - Parking zone management system - Google Patents

Abstract

PURPOSE:To allow vehicles to quickly enter to and go out from a parking zone by recognizing contents of the number plate of a vehicle to record the entrance time and recognizing the number plate to calculate the parking time at the time of exit. CONSTITUTION:When a vehicle enters into the parking zone, pictures of front and rear number plates of the vehicle are taken n by picture input means 1a and 1b, and a picture processing means 4 extracts character information. A control means 5 successively compares extracted character information of number plates with character information of number plates already stored in storage means 3a and 3b; and when the same character information is not found, extracted character information of number plates is paired with the present time and is stored in storage means 3a and 3b. When the same character information is found, the difference between the present time and the time stored in storage means 3a and 3b together with this character information is calculated, and the calculation result is displayed on a display means 8.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a parking lot management system used for managing entry and exit of a parking lot.

<Prior Art> Conventionally, when entering the building, a person receives a ticket with the time displayed on it, but when entering the building, there is often no one present, and only a ticket issuing machine is installed.

<Problems to be Solved by the Invention> However, in the case of tickets, there is a risk of losing them, and it is necessary to open the window on rainy days to get the tickets while getting wet. Additionally, most ticket machines are located on the right side when facing the direction of travel, making it difficult to obtain tickets when there are no passengers in left-hand drive cars, which have become more common in recent years.

Therefore, the present invention recognizes the content of the license plates attached to the front and rear of the car, records the time when the car entered the parking lot, and then recognizes the license plate again when leaving the parking lot to determine how long the same car has been parked in the parking lot. The purpose of this invention is to solve the above-mentioned drawbacks by calculating the time required.

Means for Solving the Problems> In order to achieve the above object, the present invention provides an image input means for capturing an image of a license plate of a vehicle, and an image input method for capturing an image of a license plate captured by the image input means. an image processing means for extracting character information; a storage means for storing the character information extracted by the image processing means and the date and time of extraction of the character information as a pair; and image processing after input by the image input means. The character information of the vehicle license plate extracted by the means is successively compared with the character information of the vehicle license plate already stored in the storage means, and if there is no identical character information as a result of the comparison, the character information is extracted this time. The character information of the license plate of the vehicle that has been inspected and the current date and time are stored in the storage means, and if the same character information is found as a result of the comparison, the current date and time and the same character information are stored in the storage means. This parking lot management system is characterized by comprising a control means for calculating and displaying the difference between the date and time when the parking lot management system was used.

Function: When entering the parking lot, an image of the vehicle's license plate is captured by the image input means. The image processing means extracts character information from the captured image. The control means successively compares the character information of the extracted license plate of the vehicle with the character information of the license plate of the vehicle already stored in the storage means, and if the same character information is not found, the number of the vehicle extracted this time is used. The character information on the plate and the current date and time are paired and stored in a storage means. On the other hand, if there is identical character information, the difference between the current date and time and the matching date and time stored in the storage means together with the next character information is calculated, and the calculation result is displayed on the display means.

<Example> Hereinafter, a detailed explanation will be given using the drawings. In Figure 1,
1atlb is a camera, 2a and 2b are A/D converters, 3a
+3b is a memory for recording images input from the camera lawlb. Reference numeral 4 denotes an image recognition section, which will be explained in detail with reference to FIG.

5 is a control unit, which includes a CPU 51. ROM52. RAM53
It consists of 6 is an external recording device, 7 is an operation unit,
8 is a display section. From camera 1 to memory 3 at
The reason why there are two b is because there is a risk of false detection due to dirt on the plate if the judgment is made based on only one of the front and rear. Cameras 1a+lb are installed facing each other so that they can take pictures of the front and rear plates when the car is stopped at the entrance of the parking lot. In addition, since the mounting position of the plate number differs depending on the vehicle model, etc., it is attached to the pan heads 9a and 9b, which are equipped with a tilt mechanism for vertical alignment and a burn mechanism for horizontal alignment. The reception of the signal is controlled. In addition, since the length of the vehicle differs depending on the type of vehicle, the camera has a zoom mechanism, and in order to make the size of the plate taken from the camera uniform, the zoom magnification is can be controlled. Other systems will be installed at toll booths at the exit of parking lots or at control rooms. camera la,
The video signals taken in from 1b (assuming 1a shows the front plate and lb shows the back plate) are respectively A/
Digitally converted by D converters 2a, 2b, memories 3a, 3
The image is recorded at 9 and output to the image recognition section 4 at b.

The image processing section 4 will be explained using FIG. 2.

In FIG. 2, 41 is an input changeover switch, 42 is a bandpass filter, 43 is a binarization processing section, 44 is a thinning processing section, 45 is a memory, 46 is a filter level adjustment section, a threshold adjustment section, 47 gives a threshold value to the binarization processing section 43. First, the switch 41 is on the 4a side, and the data on the 4a side of the memory 3 is loaded. The data that has passed through the switch 41 passes through a bandpass filter 42 to remove noise in the high-frequency and low-frequency components of the data. The noise referred to here refers to information that is unnecessary for the information that is desired to be obtained, and is actually dirt on the plate. Next, the data enters a binarization processing section 43 and binarizes the data that has passed through the bandpass filter 42. Binarization is when input video from a camera is converted into a digital image by A/D conversion, and even if it is black and white data, gradation is added and the number of bits per pixel is increased (for example, 8 bits per pixel). By weighting, it is displayed as a grayscale image. This grayscale image is judged by a certain level lv (threshold value), and if the density value is higher than the threshold value, the value of that pixel is set as %1' (white), and conversely, if it is lower, the pixel This is the process of changing the value of 'O' (black) to create a completely black and white image. What is important here is how to decide the threshold value.If it is too low, most of the data will be '1'.There are various ways to decide the threshold value, but in this system, the target image is of a car. In the case of license plates, the contrast is relatively clear (green on a white background, black on a yellow background, or vice versa), so it is okay to use a certain value, but it can be changed. Binarization processing converts the image into a black and white image. The resulting image is transferred to the line thinning processing unit 44. In general, line thinning in image processing refers to thinning the line width from a certain figure to draw a center line with a width l. The binarized image is thinned by the thinning processing unit 44 to obtain an image of characters and numbers with a line width l, and is recorded in the memory 45.The recorded image is as shown in FIG. As an image, the location of text information can be roughly divided into four areas.

In FIG. 8, kanji or hiragana are mainly displayed at 81, numbers are displayed at 32, hiragana is at 88, and numbers are displayed at 34. The numbers at 82, 83, and 84 are in hiragana, and the size and pattern of letters or numbers are fixed.

Regarding 81, the jurisdiction in which the car is registered is displayed, and it is often written in kanji, etc. In this case,
Recognizing all characters requires a considerable amount of time, so the line recognition time is shortened by calculating the number of end points and branch points of the line as a result of thinning processing. Additionally, there may be additions or changes to the registration jurisdiction, but this can be handled by making additional corrections from the operation unit 7. Here, if the size of the characters is different, there is a risk that the characters will not be recognized, so after being binarized by the binarization processing unit 43, the position and size of the plate are calculated in the control unit 5, and if the position is shifted, This problem is solved by sending a control signal to the pan head 9a and, if the sizes are different, to the camera and adjusting so that the center and size of the screen are uniform.
The results obtained from the information in the RAM 53 and the information in the RAM 53 are -
It is temporarily recorded in RAM 5B. The location where the data is recorded at this time is a location different from that of the data read from the external recording device 6.

Next, the same process is performed on the rear license plate obtained from camera lb, and the character information of the plate is recorded in RAM5B, and the information obtained from the front plate (v-) is compared with the information obtained from the rear plate. However, if they do not match, the control unit 5 takes action by adjusting the level value of the filter 46 and the threshold value of the threshold adjustment unit 47, and if the preceding and succeeding information match, it is recorded in the external recording device 6. . However, if they do not match due to extreme dirt, peeling paint, or damaged plates, please write a note on display 8 located at the exit of the parking lot or in the control room! This is handled by displaying the contents of J3a*3b and inputting character information using the operation unit 7 (see FIG. 4 84 and S7).

The vehicle license plate information obtained as described above is sequentially compared with the vehicle license plate information already stored in the external recording device 6.

As a result, if there is no license plate information in the external recording device 6 that matches the vehicle license plate information obtained this time,
Since this is a newly entered vehicle, the current time and vehicle license plate information are newly recorded in the external recording device 6.

On the other hand, if there is a match as a result of the comparison, the vehicle is to be exited, so the date and time data recorded in the external recording device 6 is read out along with the license plate information of the matching vehicle, and the current date and time are read out. The control section 5 calculates the difference between the two and displays it on the display section 8. At this time, the total charge obtained by calculating the product of the obtained time and the charge per unit time previously limited by the operation unit 7 may be displayed. The above flow is shown in Figure 4.

<Effects of the Invention> As described above, by using image recognition for parking lot management, entry and exit can be performed more quickly than before. Fig. 1 is a basic configuration diagram of the present invention, and Fig. 2 is similar to Fig. 1. FIG. 8 is a block diagram of the image recognition unit in the image recognition section, and FIG. 8 shows the position of character information in the image captured from the camera. FIG. 4 is a flowchart showing the operation of the entire system.

l...Camera, 2...A/D converter, 3.
...Memory, 4...Image recognition unit, 5...Control unit, 51...CPU, 52...ROM
, 5B...RAM.

6...External recording device, 7...Operation unit, 8...
Display section.

41-W switching switch, 42...Band pass filter, 43...Binarization processing unit, 44...
・Thinning processing unit, 45...Memory, 46...
-Level adjustment section, 47...Threshold adjustment section.

Claims (1)

[Scope of Claims] 1. Image input means for capturing an image of a license plate of a vehicle; image processing means for extracting character information from the image of the license plate captured by the image input means; and the image processing means. storage means for storing a pair of character information extracted by the image processing means and the date and time when the character information was extracted; and character information of the license plate of the vehicle extracted by the image processing means and the vehicle already stored in the storage means. a comparison means for sequentially comparing the character information of the license plate of the vehicle, and a storage means for storing the character information of the license plate of the vehicle extracted this time and the current date and time if the same character information is not found as a result of the comparison by the comparison means; control means for calculating the difference between the current date and time and the date and time stored in the storage means together with the same character information and displaying the difference on the display means if the same character information is found as a result of the comparison; A parking lot management system comprising: