Feature extraction and classification method of license plate characters based on projective symmetry

Abstract

The invention proposes a license plate character feature extraction and classification method which takes projection symmetry as a prerequisite judgment condition. In this method, the 26 letters and 10 numbers that may appear in the license plate characters are firstly extracted with projection symmetry as the judgment condition for character feature extraction, and they are divided into vertical projection symmetry, horizontal projection symmetry, central point symmetry, and no symmetry. Large categories, so as to realize the rough classification of license plate characters; after thinning and normalization transformation, the feature extraction of points and rings is carried out to complete the fine classification of license plate characters. The invention combines the projection symmetry with the point and ring feature extraction method to set the license plate character classifier, laying the foundation for the final realization of the license plate character recognition. This method has a good recognition effect on confusing characters, such as "0" and "D", "8" and "B", "7" and "T", which makes the recognition speed and accuracy of license plate characters get improved.

Description

technical field [0001] The invention relates to an automatic recognition method for a character image of a motor vehicle license plate, belonging to the technical fields of pattern recognition and computer image processing. Background technique [0002] With the development of traffic modernization, the automatic recognition technology of motor vehicle license plate has been paid more and more attention by people. The automatic license plate recognition technology is an important part of the intelligent transportation system, and the quality of the character feature extraction of the license plate will directly affect the setting of the classifier, which plays an extremely critical role in improving the speed and recognition rate of the license plate. License plate recognition technology mainly involves image processing, pattern recognition and other technologies. The feature extraction and classification of license plate characters will directly affect the performance of t...

AI Technical Summary

Problems solved by technology

[0004] In character recognition, a feature is an attribute or measure of a certain type of pattern. For different recognition objects, different feature extraction methods must be considered. It is difficult to have a unified method and theory.

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