A license plate correction method and device and a video acquisition device

Abstract

The invention discloses a license plate correction method, device and a video acquisition device, wherein the license plate correction method includes: acquiring an image to be detected and a target detection and recognition model based on a convolutional neural network; The target detection and recognition model of the network detects four corner point information of the target license plate in the image to be detected; the corner point information includes: square area, corner point category and confidence of the corner point; according to the four corner point information of the target license plate corner point information, and perform license plate correction on the target license plate in the image to be detected. The technical scheme of the invention can accurately describe the various deformations on the plane graph caused by the rotation of the license plate in the three-dimensional space, and the deformed license plate in the three-dimensional space can be corrected by locating the information of the four corner points, and it is affected by the change of the license plate number The impact of the method is small, the detection rate is high, the mispicking rate is low, the recognition rate of the corner point category is high, and the positioning is accurate.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to a license plate correction method and device and a video acquisition device. Background technique [0002] With the continuous improvement of economic level and people's living standards, vehicles in large, medium and small cities are constantly increasing. At the same time, the ensuing traffic problems have attracted more and more attention. In the process of identifying traffic violations, the automatic and accurate identification of illegal vehicle license plates is particularly important. However, in the license plate recognition process of illegal vehicles, it is first necessary to correct the tilt direction of the license plate in the image to be detected. At present, the more commonly used method for analyzing the tilt direction is to analyze the tilt direction of the characters through principal component analysis (PCA) and other methods, and determine the tilt...

AI Technical Summary

Problems solved by technology

[0003] However, in the actual process of determining the inclination direction of the license plate, it will be interfered by some inclined characters in the license plate, thereby affecting the judgment of the inclination direction of the license plate. For example, if there are multiple "7"s in the license plate, it is easy to cause misjudgment of the inclination direction of the license plate; Moreover, determining the tilt direction of the license plate in the prior art is usually limited to dealing with the rotation of the license plate in the camera image plane, and is invalid for any rotation of the license plate in three-dimensional space.

For example, the perspective deformation of the license plate in the three-dimensional space will cause the characters to produce a visual effect of large and small characters. The method of determining the tilt direction of the license plate in the prior art cannot realize the correction of this type of license plate.

In addition, the recognition algorithm of license plate tilt angle in the prior art does not have scale invariance. For example, there are requirements on the size of characters. If the size of characters changes greatly, the accuracy of the algorithm will be greatly affected.

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