End-to-end license plate identification method

A license plate recognition and license plate technology, applied in the field of license plate recognition, can solve the problems affecting character recognition accuracy, difficulty, and decrease in license plate recognition rate, and achieve the effects of ensuring position regression accuracy, reducing interference, and overcoming gradient saturation.

Active Publication Date: 2017-06-13
PCI TECH GRP CO LTD
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AI Technical Summary

Problems solved by technology

[0003] Traditional license plate recognition methods usually include license plate detection, license plate correction, license plate segmentation, and character recognition. For license plate pixels greater than 120 pixels, and the license plate is not stained, the license plate deflection angle is less than 30 degrees, and the license plate has no backlight. , the license plate recognition rate is greater than 95%, but for small license plates (less than 100 pixels) and the licens

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  • End-to-end license plate identification method

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Embodiment 1

[0020] An end-to-end license plate recognition method, a 3-layer fully convolutional neural network is designed to quickly predict the heat map of the character, so as to obtain the candidate character area. The design and training method of the specific structure of the network are as follows:

[0021] 1) Network structure: first layer: 3x3 convolution, stride=1, pad=1, number of filters 128, activation function AFM, connected to 2x2 pooling, stride=2, pad=0; second layer: 3x3 Convolution, stride=1, pad=1, number of filters 256, activation function AFM; third layer: 3x3 convolution kernel, stride=1, pad=1, number of filters 512, activation function AFM; use the first The three-layer feature map encodes the heat map. This network structure has two advantages. One is that the heat map is mapped from the high-resolution feature map, and the candidate character area obtained is more accurate. The second is the activation function AFM, which calculates two groups The mean value of...

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Abstract

The invention discloses an end-to-end license plate identification method. The method comprises the steps of firstly segmenting a license plate region to serve as an input according to a license plate locating result; secondly predicting a license plate character thermodynamic diagram by adopting a designed three-layer full convolutional neural network, and obtaining candidate character regions according to the thermodynamic diagram; thirdly performing classification and position correction on the candidate character regions by adopting a designed seven-layer deep convolutional neural network model to obtain character sequences and position sequences; and finally selecting out the character sequences meeting Chinese mainland license plate standards by adopting a template-based optimal path algorithm, wherein the selected character sequences are identification results. The whole network adopts a multi-task combined training mode; the input is a license plate color image, and an output is a license plate number; and the method avoids the defect that a license plate needs to be accurately segmented in a conventional license plate identification method, and can effectively increase the license plate identification rate in a complex scene.

Description

technical field [0001] The invention relates to the technical field of license plate recognition, in particular to an end-to-end license plate recognition method. Background technique [0002] With the development of computer technology and information processing technology, the information processing ability of computer has been continuously improved, and computer vision technology has been widely used in intelligent transportation and electronic police systems based on multimedia, pattern recognition and artificial intelligence technology around the world. Among these applications, 96% of the automated systems use the automatic license plate recognition technology, and more than 75% of the systems use license plate recognition as the core application. [0003] Traditional license plate recognition methods usually include license plate detection, license plate correction, license plate segmentation, and character recognition. For license plate pixels greater than 120 pixels...

Claims

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Application Information

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IPC IPC(8): G06K9/34G06N3/04G06N3/08
CPCG06N3/04G06N3/08G06V30/153G06V20/625
Inventor 周涛冯琰一吴志伟
Owner PCI TECH GRP CO LTD
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