License plate location method based on gray level jump and character projection interval mode

A technology of gray-scale jumping and license plate positioning, which is applied in character and pattern recognition, instruments, computer components, etc., and can solve problems such as being easily affected by light and projection being easily affected by special characters

Active Publication Date: 2014-01-01
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the defects and deficiencies mentioned above, and provide a license plate location method based on grayscale jump and character projection interval mode, so as to solve the problem that the existing license plate location method is easily affected by light, projection is easily affected by special characters, etc. technical problem

Method used

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  • License plate location method based on gray level jump and character projection interval mode
  • License plate location method based on gray level jump and character projection interval mode
  • License plate location method based on gray level jump and character projection interval mode

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Experimental program
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Embodiment Construction

[0042] With reference to accompanying drawing, specific implementation steps are as follows:

[0043] (1), grayscale processing

[0044] The weighted average method is used to grayscale the license plate image, and the calculation formula is as follows:

[0045]

[0046] in R ( x , y ), G ( x , y ) and B(x, y) represent ( x ,y ), the red, green and blue components of the pixel at ), f ( x , y ) means a pixel ( x , y ) gray value.

[0047] (2) Judging whether the image illumination is abnormal

[0048] Analyze the distribution characteristics of the brightness in the license plate grayscale image, and judge whether the image is normally illuminated or abnormally illuminated. The calculation formula is as follows:

[0049]

[0050] in, f ( x,y ) is the pixel point in the grayscale image ( x , y ) gray value, h and w Indicates the height and width of the image, M is the average gray value of the gray image, D Defined as an indicator describing the bri...

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Abstract

The invention discloses a license plate location method based on a gray level jump and a character projection interval mode, and relates to the license plate location method. The license plate location method comprises the following steps: (1) conducting gray level processing, (2) judging whether image illumination is normal or not, (3) processing binarization, (4) determining a license plate characteristic line by conducting line scanning on gray level jump characteristics, therefore conducting location on the upper border and the lower border of a license plate, (5) adjusting the character projection interval mode by conducting column scanning, and conducting location on the left border and the right border of the license plate. According to the method, the phenomenon that no matter whether the light condition for capturing a license plate image is good or bad, the information of the license plate can not be lost after the binarization, the success rate of the license plate binarization is greatly improved, after vertical projection is carried out on the license plate, and the character width consistency of the license plate is achieved by means of changing the projection of the character '1' and the projection of the character ' '. Therefore, the fixed and uniform license plate character projection interval mode is utilized for conducting location on the left border and the right border of the license plate, interference on the non-license-plate area can be effectively removed, and the accuracy rate of license plate location is improved.

Description

technical field [0001] The invention relates to a license plate positioning method, in particular to a license plate positioning method based on gray scale jump and character projection interval mode. Background technique [0002] Since the reform and opening up, with the rapid development of the economy, the number of motor vehicles has continued to increase, and the requirements for road traffic information and public security management have become more and more stringent. Intelligent transportation technology has emerged as the times require and has penetrated into our lives. The systems we are familiar with such as crossing red light violation monitoring, expressway speeding violation detection, ETC electronic non-stop charging, parking lot intelligent management, community vehicle management and checkpoint systems are all successful applications of intelligent transportation technology. These systems all include license plate recognition modules, and license plate posi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/00G06K9/54
Inventor 高飞邢涛张元鸣陆佳炜毛家发梅凯城韩政高肖刚
Owner ZHEJIANG UNIV OF TECH
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