VEHICLE LICENSE PLATE RECOGNITION METHOD AND SYSTEM THEREOF
First Claim
1. A vehicle license plate recognition method comprising:
- Step (a);
converting an image of a vehicle into a gray-level image, calculating edge densities of said gray-level image, and defining a region where a vehicle license plate image exists according to said edge densities and a vehicle license plate specification;
Step (b);
detecting a text area of said vehicle license plate image, partitioning said text area into a plurality of character images, and binarizing said character images to obtain a plurality of binarized character images;
Step (c);
recognizing a plurality of characters from said binarized character images;
Step (d);
recombining said characters into a character string of a vehicle license plate and outputting said character string; and
Step (e);
receiving a next image of said vehicle, which is captured at a different time point, and repeating steps of from said Step (a) to said Step (d) to obtain a new character string from said next image;
comparing said character string with said new character string character by character to obtain a comparison result for verifying reliability of recognition.
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Abstract
A vehicle license plate recognition method and a system thereof are disclosed. A region where a vehicle license plate image exists is detected according to the edge densities of an input image and a vehicle license plate specification. A text area of the vehicle license plate image is divided into a plurality of character images. The character images are binarized to obtain a plurality of binarized character images. A plurality of characters is recognized from the binarized character images. The characters are recombined to form a character string. The abovementioned steps are repeated to obtain a new character string from another image of the same vehicle, which is captured at a next time point. The character string is compared with the new character string character by character to obtain a comparison result for verifying reliability of recognition through a voting technique.
65 Citations
18 Claims
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1. A vehicle license plate recognition method comprising:
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Step (a);
converting an image of a vehicle into a gray-level image, calculating edge densities of said gray-level image, and defining a region where a vehicle license plate image exists according to said edge densities and a vehicle license plate specification;Step (b);
detecting a text area of said vehicle license plate image, partitioning said text area into a plurality of character images, and binarizing said character images to obtain a plurality of binarized character images;Step (c);
recognizing a plurality of characters from said binarized character images;Step (d);
recombining said characters into a character string of a vehicle license plate and outputting said character string; andStep (e);
receiving a next image of said vehicle, which is captured at a different time point, and repeating steps of from said Step (a) to said Step (d) to obtain a new character string from said next image;
comparing said character string with said new character string character by character to obtain a comparison result for verifying reliability of recognition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A vehicle license plate recognition system comprising
a license plate detection module detecting an image, converting said image into a gray-level image, calculating edge densities of said gray-level image, and defining a region where a vehicle license plate image exists according to said edge densities and a vehicle license plate specification; -
a character partition module connected with said license plate detection module, partitioning said vehicle license plate image into a plurality of character images, and binarizing said character images to obtain a plurality of binarized character images; a character recognition module connected with said character partition module, recognizing characters from said binarized character images; a character recombination module connected with said character recognition module, recombining said characters into a character string of a vehicle license plate, and outputting said character string; and a voting module connected with said character recognition module, obtaining a new character string generated in a next time point, comparing said character string with said new character string character by character to generate a comparison result for verifying reliability of recognition. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification