Kernel density estimation-based license plate character segmentation method

A technology of kernel density estimation and character segmentation, which is applied in the field of intelligent transportation, can solve the problems of inability to work normally, cannot be binarized well, and has poor effect of license plate character binarization, so as to reduce license plate contamination, improve accuracy, The effect of eliminating sticking

Inactive Publication Date: 2013-07-17
ZHEJIANG ICARE VISION TECH
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Problems solved by technology

[0002] The current license plate character segmentation technology is mainly based on the character binarization of the license plate area, and is constrained by the prior rules of the license plate character arrangement to obtain an effective license plate character area. This method is disturbed by the environment or the license plate itself. It has a certain anti-interference ability, but it still cannot work normally when the character binarization effect is poor
[0003] In order to solve the problem of poor binarization of license plate characters, existing methods include clustering character foreground points, estimating the width and strokes of license plate characters, and detecting license plate borders.
These methods can improve the binarization effect, but in extreme cases, there are still many cases that cannot be binarized well.

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  • Kernel density estimation-based license plate character segmentation method
  • Kernel density estimation-based license plate character segmentation method
  • Kernel density estimation-based license plate character segmentation method

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Embodiment Construction

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] Such as figure 1 As shown, a license plate character segmentation method based on kernel density estimation, including:

[0021] 1) Using a known bilinear interpolation method, the size of the license plate image is normalized to 120×40, that is, 120 pixels in the horizontal direction and 40 pixels in the vertical direction;

[0022] 2) adopt known Gaussian high-pass filtering method, carry out sharpening edge processing to the license plate image after normalization;

[0023] 3) Using a known Gaussian low-pass filtering method to remove noise from the edge-sharpened license plate image.

[0024] (2) Using the gradient in the horizontal direction, project the preprocessed image in the horizontal direction to segment the upper and lower edges of the license plate, and calculate each horizontal block Gradient value on , the average gradient of all horizontal...

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Abstract

The invention relates to a kernel density estimation-based license plate character segmentation method. At present, the conventional methods have the defect that binaryzation cannot be performed well under the extreme condition. The method comprises the following steps of: performing preprocessing of normalization, edge sharpening and noise removal on a license plate image; determining a character area of a license plate; finding a pixel value of which the probability of occurrence is maximum in the current kernel probability density curve and the kernel density half width of the point, and performing image binaryzation by utilizing the two parameters; and extracting a segmentation result of which the score is maximum within the width range to be used as a final character segmentation result. By the method, the distribution of character pixels can be determined accurately; and compared with the common iteration binaryzation method, the method has the advantage that the ambient interference resistant capacity is enhanced greatly.

Description

technical field [0001] The invention belongs to the technical field of intelligent transportation, and relates to a character segmentation method based on kernel density estimation. Background technique [0002] The current license plate character segmentation technology is mainly based on the character binarization of the license plate area, and the effective license plate character area is obtained by constraining the prior rules of the license plate character arrangement. This method is disturbed by the environment or the license plate itself. It has a certain anti-interference ability, but it still cannot work normally when the character binarization effect is poor. [0003] In order to solve the problem of poor binarization of license plate characters, existing methods include clustering character foreground points, estimating the width and strokes of license plate characters, and detecting license plate borders. These methods can improve the binarization effect, but t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06K9/34
Inventor 尚凌辉蒋宗杰王弘玥高勇
Owner ZHEJIANG ICARE VISION TECH
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