License plate location method

A license plate positioning and license plate technology, which is applied in instruments, computing, character and pattern recognition, etc., can solve the problems of difficult to accurately measure and predict the image quality, difficult to accurately locate the license plate, and the image contrast is not strong, so as to improve the global contrast and The effect of local contrast, enhanced detail, improved accuracy

Active Publication Date: 2012-06-27
HUAZHONG UNIV OF SCI & TECH
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Problems solved by technology

This method directly uses the color images collected by the equipment to realize the license plate location. It makes full use of the collected image information and improves the accuracy of the license plate location. However, due to the difference in image acquisition equipment and the influence of external factors, the The quality of the collected images is difficult to accurately measure and predict, and the license plate location method based on color images is greatly affected by the image quality, especially for the situation where the image contrast is not strong and dark, it is difficult to accurately locate the license plate

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Embodiment Construction

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] Step 1, image preprocessing, the process is as follows figure 2 As shown, the processing results are as follows Figure 4 shown.

[0021] (1) The vehicle image (such as image 3 Shown) the function is expressed in the following form:

[0022] I(x,y)=R(x,y)L(x,y)

[0023] Where (x, y) is the position of the midpoint of the image, I represents the original vehicle image, R represents the reflected light component, which represents the illuminated light component, and the illuminated light component L describes the brightness of the surrounding environment, which has nothing to do with the scene; and the reflected light component is R Refers to the reflective ability of the scene, which has nothing to do with lighting, and it contains the detailed information of the scene.

[0024] (2) Take the logarithm on both sides of the...

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Abstract

The invention discloses a license plate location method, which comprises the following steps of: (1) preprocessing an original vehicle image I (x,y) to obtain an enhanced vehicle image I1 (x,y); (2) correcting the color values of points in the vehicle image I1 (x,y) to obtain a corrected vehicle image I2 (x,y); (3) scanning the corrected vehicle image I2 (x,y), and extracting a blue-and-yellow-concentrated region as a license plate candidate region; and (4) checking a license plate region, i.e. judging the size of the current region, accounting the current region as the license plate region if the region is in a set range, and finishing license plate location. With the adoption of the license plate location method disclosed by the invention, the license plates in vehicle images acquired under general conditions can be located, and the license plates in vehicle images photographed under complicated conditions, such as dim light, rain, snow, smoke and the like, can also be located, so that the license plate location method has important practical value in license plate recognition.

Description

technical field [0001] The invention belongs to the field of computer image recognition, and in particular relates to a license plate positioning method. Background technique [0002] License plate recognition (LPR) technology is an important means of intelligent transport system (ITS) management, and its task is to automatically locate and recognize vehicle license plates by collecting, analyzing, and processing images. The LPR system can be widely used in important occasions such as security checkpoints, parking lot management, road violation management, highway inspection, and monitoring of black-brand vehicles. The license plate location in the license plate recognition system is the basis of license plate segmentation and character recognition, and it is also a key step to improve the license plate recognition rate. Many scholars are doing exploration and research on license plate location. At present, the methods of license plate location are mainly divided into two ...

Claims

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Application Information

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IPC IPC(8): G06K9/32G06K9/54
Inventor 喻莉张彦钟刚周鹏
Owner HUAZHONG UNIV OF SCI & TECH
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