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Tilt vehicle license plate recognition method and device

A technology of inclined license plate and recognition method, which is applied in the field of data recognition, can solve problems such as inability to locate and missed detection of license plate, and achieve the effect of improving recognition rate and reducing missed detection

Active Publication Date: 2016-01-27
NETPOSA TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Due to the limitations of the Hough transform algorithm, the existing license plate recognition process can only locate and recognize the license plate with a small inclination angle (the inclination angle of the license plate is less than 40 degrees), and the license plate with an excessive inclination angle (the inclination angle of the license plate is less than 40 degrees). 60 degrees or more), the license plate cannot be positioned, which will easily lead to the occurrence of missed detection of the license plate

Method used

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  • Tilt vehicle license plate recognition method and device
  • Tilt vehicle license plate recognition method and device
  • Tilt vehicle license plate recognition method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0078] see figure 2 , the present embodiment provides a tilted license plate recognition method, the method includes the following steps:

[0079] Step 200, the tilted license plate recognition device determines the character area of ​​the license plate from the captured license plate image.

[0080] The characters recorded in the license plate are formed by a combination of Chinese, English and numeric characters, and are used to represent the unique vehicle number of the vehicle.

[0081] The license plate image is obtained when a vehicle passes through a high-speed toll station or an intersection in a city, and the cameras installed at the high-speed toll station or intersection will take pictures of the license plate of the passing vehicle. After the camera takes pictures of the vehicle to obtain the license plate image, it will send the license plate image to the tilted license plate recognition device, so that the tilted license plate recognition device can recognize t...

Embodiment 2

[0146] see image 3 , the present embodiment provides another inclined license plate recognition method, the method includes the following steps:

[0147] Step 300, locating the center point of the license plate;

[0148] This embodiment proposes a brand-new license plate detection and positioning technology based on the center point of the license plate. Through the unique edge response characteristics in the license plate area, the edge response value in the longitudinal direction is selected, and the positioning is performed by interpolation and non-maximum value suppression algorithm. The local maximum point of the edge response in the image is selected as the center point C1 of the candidate license plate area.

[0149] The sobel operator is used to extract the edge response, the original image is A, and the vertical edge detected image is Gx, the calculation formula is as follows:

[0150] G x = ...

Embodiment 3

[0181] see Figure 4 , the present embodiment provides a tilted license plate recognition device, the tilted license plate recognition device is used to implement the above tilted license plate recognition method, the device includes: a license plate character area determination module 400, a license plate character area correction module 402, a character tilt angle calculation module 404, character correction module 406 and recognition module 408;

[0182] License plate character area determining module 400, for determining the license plate character area from the license plate image taken;

[0183] The license plate character area correcting module 402 is connected with the license plate character area determination module 400, and the license plate character area is corrected according to the overall inclination angle of the license plate in the license plate image to obtain a corrected image of the license plate character area;

[0184] The character inclination angle ca...

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Abstract

The invention provides a tilt vehicle license plate recognition method and device. The method comprises the following steps: determining a vehicle license plate character area from a shot vehicle license plate image; correcting the vehicle license plate character area according to the overall tilt angle of the vehicle license plate in the vehicle license plate image so as to obtain a corrected image of the vehicle license plate character area; calculating the character tilt angle of the vehicle license plate according to the gray value of pixel points in the corrected image; correcting the characters in the corrected image according to the character tilt angle so as to obtain an optimized image of the vehicle license plate character area; and recognizing the characters in the optimized image so as to obtain the vehicle license plate in the vehicle license plate image. Through the method and device provided by the invention, the vehicle license plates with large tilt angles can be recognized.

Description

technical field [0001] The present invention relates to the field of data identification, in particular to a method and device for identifying inclined license plates. Background technique [0002] License plate recognition is based on digital image processing and computer vision and recognition technology, which analyzes the captured vehicle images to obtain the license plate number of each car. With the development of urban traffic, the technology of license plate recognition has been in the It has been widely used in the investigation and punishment of vehicle violations and highway tolls. [0003] The existing license plate recognition process includes: locating the license plate position in the image through an image recognition algorithm such as the Hough transform algorithm and performing association matching with the existing license plate template to determine the character area of ​​the license plate; and then segmenting the characters in the license plate; Finall...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/32
CPCG06V10/243G06V20/625
Inventor 许健万定锐
Owner NETPOSA TECH