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A license plate location method and device

A license plate, license plate image technology, applied in character and pattern recognition, instruments, computer parts and other directions, can solve the problems of color interference, high false detection rate, edge contour interference and so on

Active Publication Date: 2018-02-16
INST OF SOFTWARE APPL TECH GUANGZHOU & CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since black and white are common colors in license plates, they will be subject to more color interference in many scenes, especially when the proportion of the license plate in the image is not very large or the scene is more complex When the edge information is rich, the above-mentioned The method will produce edge contour interference, resulting in a high false detection rate

Method used

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  • A license plate location method and device
  • A license plate location method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0084] Such as figure 1 As shown, it is a flowchart of a method for locating a license plate disclosed in Embodiment 1 of the present invention, which mainly includes the following steps:

[0085] Step S101, obtaining the original license plate image A, and using the original license plate image A to perform grayscale conversion to obtain the corresponding grayscale image B;

[0086] Step S102, performing edge extraction and binarization on the grayscale image B to obtain a binarized edge image C;

[0087] In step S102, the edge of the grayscale image B is extracted, and the extracted image is binarized to obtain a binarized edge image C, and the pixel value of the edge point in the edge image C is 1 , and other pixel values ​​are 0, in this way the edge points of the license plate area can be preserved.

[0088] Step S103, using the edge map C and the preset three sets of color threshold matching schemes to perform color matching constraint detection on the original license...

Embodiment 2

[0105] Based on a license plate location method disclosed in the first embodiment of the present invention, as figure 1 The three sets of preset color threshold collocation schemes shown in step S103, the generation process includes the following steps:

[0106] Step S201, counting the pixel values ​​of black and white colors on the license plate in different scenes, the different scenes at least include strong light environment, low light environment, and normal light environment;

[0107] Step S202, using the statistically obtained pixel values ​​of the black and white colors, a preset high threshold range, a preset middle threshold range, and a preset low threshold range, to obtain three preset color threshold matching schemes;

[0108] Wherein, the preset high threshold range is 230-200, the preset middle threshold range is 180-120, and the preset low threshold range is 100-60.

[0109] Based on a license plate location method disclosed in the first embodiment of the pres...

Embodiment 3

[0142] Such as figure 2 As shown, it is a license plate locating device disclosed in Embodiment 3 of the present invention, which mainly includes: a gray scale conversion unit 101, a binarization unit 102, a first color constraint detection unit 103, or an operation unit 104, and a first extracted connected domain unit 105 , calculation unit 106 , second color constraint detection unit 107 , second extracted connected domain unit 108 , preliminary screening unit 109 and positioning output unit 110 .

[0143] Wherein, the grayscale conversion unit 101 is used to obtain the original license plate image A, and use the original license plate image A to perform grayscale conversion to obtain a corresponding grayscale image B;

[0144] The binarization unit 102 is configured to perform edge extraction on the grayscale image B and perform binarization processing to obtain a binarized edge image C;

[0145] The first color constraint detection unit 103 is configured to perform color...

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Abstract

The invention discloses a license plate location method and device. The method performs the first color matching constraint detection on the original license plate image through multiple sets of preset color threshold matching schemes and edge maps, and extracts connected domains based on the obtained result atlas. Obtain the license plate candidate area set integrated by each connected domain, and then obtain the adaptive color matching schemes of the N candidate areas based on the license plate candidate area set, and then obtain the color matching scheme based on the N adaptive color matching schemes. The final license plate candidate area is obtained, and the final license plate candidate area is initially screened and finally positioned to output the final license plate area set to complete the license plate positioning. The present invention gradually narrows down the detection area by means of self-adaptive color constraint detection, and makes full use of the edge and color of the license plate to eliminate various environmental interferences, especially the interference of light, dirt, etc. Or to reduce the false positive rate.

Description

technical field [0001] The present invention relates to the technical field of digital image processing, and more specifically relates to a license plate location method and device. Background technique [0002] As cars are widely used in people's lives, based on the fact that a car corresponds to a license plate, whether it is in terms of traffic safety or daily road management, the cameras on the road can capture the license plates of vehicles passing through the camera area, and pass Recognize the license plate to obtain the information carried on the license plate, so as to realize the management of the vehicle. [0003] At present, the color of the license plate is usually used to complete the positioning of the license plate. However, the colors of the existing license plate include white characters on a blue background, black characters on a yellow background, white characters on a black background, and black characters on a white background. This positioning method i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06K9/32G06K9/54
CPCG06V20/584
Inventor 崔莹袁峰李引陈升东伍小鹏
Owner INST OF SOFTWARE APPL TECH GUANGZHOU & CHINESE ACAD OF SCI
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