CTPN system-based text line construction optimization calculation method and application thereof

Abstract

The invention discloses a CTPN system-based text line construction optimization calculation method and application thereof, and aims to solve the problems that the light of an underground parking lot is often insufficient, so that license plate images shot by most underground parking lots are poor in effect, and recognition errors are caused by poor image contrast due to the influence of other factors such as dim light and the like. Therefore, research on license plate recognition based on the non-high-definition image becomes very necessary. Part of license plate characters have double rows, and the license plate character area often has no ground color which can be distinguished from the color of the vehicle body, so that the difficulty of automatic license plate recognition is further increased. The invention aims to provide a solution for automatically recognizing the non-high-definition double-row license plate, and ensures that the recognition accuracy of the non-high-definition license plate meets the actual application requirement.

Description

technical field [0001] The invention relates to a license plate detection and recognition system and its application field. Background technique [0002] The license plate specifications currently used in Macau are based on the license plate specifications used in Portugal from 1937 to 1992. The base color of the license plate is black and the characters of the license plate are white. At the beginning, the license plates used by ordinary cars in Macau started with the letter "M", followed by "MA", "MB", and so on, followed by four digits, and one digit was added between each two digits "- " delimiter, the total number of license plate is 5 to 6 digits. In addition, there are two types of license plates in Macau. The first type of license plate puts all letters and numbers in one line, while the second type of license plate puts letters on the first line and numbers on the second line, and omits the space between letters and numbers. connector. [0003] In addition, the T...

AI Technical Summary

Problems solved by technology

However, the vast majority of Macau license plates use black as the background color of the license plate. At the same time, the body color of many vehicles is also black. When the color of the license plate is the same as the body color, the color positioning is useless.

In addition, license plate location will also be affected by light, weather and other factors, as well as factors such as the bending of the license plate itself, blurred writing, etc., which makes it more difficult to locate the Macau license plate

[0006] (2) Difficulties in character segmentation

Moreover, the various license plate specifications of Macao vehicles make it impossible to use a given standard width to perform character segmentation on the corrected license plate

[0008] (3) Difficulties in character recognition

For example, the font of the number "4" is quite different, which makes it difficult to recognize the Macau license plate

In addition, the shapes of a series of letters and Chinese characters such as "B" and "8", "O" and "0", "I" and "1", "S" and "5" are very similar, and the characteristics are not obvious. Recognition brings challenges. The "S" in the picture is recognized as "5"

[0010] To sum up, the variety of license plate types, a country’s license plate has a variety of different types of license plates, license plate background colors are various, and there are many combinations with character colors, and when there is no rivet frame and other references that can be used for positioning, the license plate It is difficult to locate, which has a great impact on the recognition rate of the license plate

In addition, the image quality of the license plate is not high, and a complete character library including the Macau license plate has not yet been built, which leads to the shortcomings of low accuracy of the current mature technical solutions for non-high-definition Macau license plate recognition

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