License plate image processing method and device

Abstract

The invention provides a license plate image processing method and device. The method comprises the steps of obtaining a license plate image and a boundary formed due to brightness difference on the license plate image, wherein the license plate image is divided into upper and lower parts through the boundary; binarizing the upper and lower part license plate images; discretizing the boundary, thereby obtaining discrete points on the boundary; and binarizing pixels according to pixel values of the pixels in a preset neighbourhood range of a column in which the discrete points are located. According to the method, the parts in the license plate image with different brightness are binarized through adoption of different thresholds; compared a the mode of carrying out general binarization through adoption of a uniform threshold, the mode has the advantages that the obtained binarized image is beneficial for follow-up character extraction and identification, the binarization effect of vehicle light and shade plates is improved, and the identification accuracy of a vehicle tail plate is improved.

Description

technical field

[0001] The invention relates to the technical field of image processing, in particular to a license plate image processing method and device. Background technique

[0002] License plate recognition technology generally includes license plate positioning, license plate image binarization, license plate character cutting, and character recognition. Among them, the license plate image binarization effect directly affects the accuracy of license plate recognition, which is the key to the entire license plate recognition technology. License plate recognition usually needs to binarize the license plate image, and extract a single character from the binary image for character recognition, so as to realize the recognition of the entire license plate.

[0003] The existing license plate image binarization processing generally adopts the adaptive global threshold method or the local adaptive threshold method. However, when performing vehicle tail plate recognition, th...

Examples

Embodiment 1

[0058] This embodiment provides a license plate image processing method, the flow chart of the method is as follows figure 1 shown. Including the following steps:

[0059] S1: Acquire a license plate image, the license plate image includes a boundary line formed by the license plate due to brightness differences, and the boundary line divides the license plate image into upper and lower parts. Specifically, the boundary line can be obtained by determining the boundary point according to the pixel value of each pixel point in the license plate image, and then performing curve fitting on the boundary point.

[0060] S2: Perform binarization processing on the upper and lower parts of the license plate image respectively. Specifically, the upper and lower parts correspond to the shaded area and the sunny area respectively, and the respective thresholds of the upper and lower parts of the license plate image can be determined by a conventional adaptive threshold method, denoted ...

Embodiment 2

[0102] This embodiment provides a license plate image processing device, the schematic diagram of which is as follows figure 2 shown. include:

[0103] The acquiring unit 10 is configured to acquire a license plate image, the license plate image includes a boundary line formed by the license plate due to brightness differences, and the boundary line divides the license plate image into upper and lower parts. Specifically, the boundary line can be obtained by determining the boundary point according to the pixel value of each pixel point in the license plate image, and then performing curve fitting on the boundary point.

[0104] The binarization processing unit 20 is configured to perform binarization processing on the upper and lower parts of the license plate image respectively. The binarization processing unit 20 includes a threshold value determination subunit, which is used to determine the respective thresholds of the upper and lower parts of the license plate image; ...

technical field

[0001] The invention relates to the technical field of image processing, in particular to a license plate image processing method and device. Background technique

[0002] License plate recognition technology generally includes license plate positioning, license plate image binarization, license plate character cutting, and character recognition. Among them, the license plate image binarization effect directly affects the accuracy of license plate recognition, which is the key to the entire license plate recognition technology. License plate recognition usually needs to binarize the license plate image, and extract a single character from the binary image for character recognition, so as to realize the recognition of the entire license plate.

[0003] The existing license plate image binarization processing generally adopts the adaptive global threshold method or the local adaptive threshold method. However, when performing vehicle tail plate recognition, th...

Examples

Embodiment 1

[0058] This embodiment provides a license plate image processing method, the flow chart of the method is as follows figure 1 shown. Including the following steps:

[0059] S1: Acquire a license plate image, the license plate image includes a boundary line formed by the license plate due to brightness differences, and the boundary line divides the license plate image into upper and lower parts. Specifically, the boundary line can be obtained by determining the boundary point according to the pixel value of each pixel point in the license plate image, and then performing curve fitting on the boundary point.

[0060] S2: Perform binarization processing on the upper and lower parts of the license plate image respectively. Specifically, the upper and lower parts correspond to the shaded area and the sunny area respectively, and the respective thresholds of the upper and lower parts of the license plate image can be determined by a conventional adaptive threshold method, denoted ...

Embodiment 2

[0102] This embodiment provides a license plate image processing device, the schematic diagram of which is as follows figure 2 shown. include:

[0103] The acquiring unit 10 is configured to acquire a license plate image, the license plate image includes a boundary line formed by the license plate due to brightness differences, and the boundary line divides the license plate image into upper and lower parts. Specifically, the boundary line can be obtained by determining the boundary point according to the pixel value of each pixel point in the license plate image, and then performing curve fitting on the boundary point.

[0104] The binarization processing unit 20 is configured to perform binarization processing on the upper and lower parts of the license plate image respectively. The binarization processing unit 20 includes a threshold value determination subunit, which is used to determine the respective thresholds of the upper and lower parts of the license plate image; ...

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