License plate positioning method in complex lighting environment based on wavelet transform

Abstract

The invention provides a license plate positioning method in a complex lighting environment based on wavelet transform. The method comprises the following steps: (1) acquiring an image including a license plate, and graying the image to obtain a gray scale image; (2) de-noising the gray scale image by using wavelet transform to obtain a de-noised image; (3) searching a license plate area, where the license plate is located, in the de-noised image; and (4) cutting the license plate area and keeping the license number information of the license plate. The license plate positioning method in a complex lighting environment based on wavelet transform can remove the influence of complex illumination on the license plate image and improve the system positioning accuracy.

Description

technical field [0001] The invention relates to a method for locating license plates in complex illumination environments based on wavelet transform. Background technique [0002] With the development of the economy, the increasing popularity of motor vehicles and the rapid development of highway transportation, the traditional manual management methods can no longer meet the needs of actual work. As an important direction of intelligent transportation systems, license plate recognition technology has gradually attracted people's attention. License plate recognition mainly includes three parts: license plate positioning, license plate character segmentation, and license plate character recognition. License plate positioning is the most important part of the three parts. The quality of license plate positioning determines whether the follow-up work can be carried out normally. [0003] The existing license plate location methods are: (1) license plate location method based on...

AI Technical Summary

Problems solved by technology

Method 3 proposes a license plate location method based on mathematical morphology. Using the mathematical morphology method to perform top-hat operation on the image, the highlight part of the license plate can be removed, but at the same time, the texture of the license plate is often severely damaged, which is not conducive to downward positioning. Work

[0004] In summary, the methods mentioned above do not fully consider the license plate positioning of the image under complex lighting

In a real-time intelligent transportation system, illumination is an important factor affecting the accuracy of license plate recognition, especially for license plate positioning under high light, and the above-mentioned algorithms cannot solve the problem well.

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