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Laser-based license plate location method, device and system

A technology of license plate positioning and laser, which is applied in the direction of instruments, calculations, character and pattern recognition, etc., can solve the problems of toll system, monitoring system influence, license plate recognition failure, camera inability to locate, etc., and achieve the effect of improving the license plate positioning ability

Active Publication Date: 2019-08-20
BEIJING WANJI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When binarizing the entire car, because the binarized data of the license plate and the shadow of the vehicle on the ground are very close, the contrast of the license plate is very inconspicuous, resulting in the disappearance of the texture of the license plate, making it impossible for the camera to locate the license plate, resulting in license plate recognition fail
On the main roads of urban roads, the traffic volume of vehicles per day is generally tens of thousands of times. When the success rate of camera recognition rate license plate is greatly reduced, it will affect the all-weather working ability of the multi-lane free flow system, and it will also cause damage to the toll system and monitoring system. certain influence

Method used

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  • Laser-based license plate location method, device and system
  • Laser-based license plate location method, device and system
  • Laser-based license plate location method, device and system

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Experimental program
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Embodiment 1

[0041] The embodiment of the present invention provides a laser-based license plate location method, such as figure 2 shown, including:

[0042] S1. When it is detected that a vehicle triggers the laser scanning line, obtain the head position of the vehicle from the updated historical frame data of the vehicle;

[0043] S2. According to the position of the front of the car, calculate the left and right position and the up and down position of the front of the car in the snapped photo so as to obtain the position area of ​​the front of the car in the snapped photo;

[0044] S3. Calculate the comprehensive confidence weight and the comprehensive left and right boundaries according to all historical frame data of the vehicle; and shrink the comprehensive left and right boundaries inwardly according to the comprehensive confidence weight to obtain the left and right positions of the license plate, and according to the first preset pixel expansion amount Extending up and down the...

Embodiment 2

[0099] In order to reflect the superiority of the license plate location method provided by the first embodiment of the present invention, the embodiment of the present invention also provides a laser-based license plate location device, such as Figure 8 shown, including:

[0100] The head position acquisition unit is used to obtain the head position of the vehicle from the updated historical frame data of the vehicle when a vehicle is detected to trigger the laser scanning line;

[0101] The head position area acquisition unit is used to calculate the left and right position and the up and down position of the head in the snapped photo according to the head position so as to obtain the head position area in the snapped photo;

[0102] The license plate position area acquisition unit is used to calculate the comprehensive confidence weight and the comprehensive left and right boundaries according to all historical frame data of the vehicle; and shrink the comprehensive left a...

Embodiment 3

[0123] The embodiment of the present invention provides a laser-based license plate positioning system, such as Figure 5 As shown, including the license plate positioning device described in Embodiment 2 and at least one laser;

[0124] At least one laser is used to send laser scanning lines to the detection area, and receive the returned laser scanning lines to provide to the license plate positioning device;

[0125] The license plate positioning device is used to detect the head position of the triggered vehicle according to the laser scanning line and determine the head position area and the license plate position area in the snapshot.

[0126] As can be seen from the above, the license plate positioning device provided in the second embodiment of the present invention and the license plate positioning system provided in the third embodiment are both realized based on the license plate positioning method described in the first embodiment, so the same technical problems ca...

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Abstract

The invention relates to a laser-based license plate positioning method, device and system. The method includes: when a vehicle is detected to trigger the laser scanning line, obtaining the head position of the vehicle from the updated historical frame data of the vehicle; calculating the left and right positions and up and down positions in the snapshot according to the head position to obtain In the area of ​​the front of the vehicle in the snapshot; calculate the comprehensive confidence weight and the comprehensive left and right boundaries according to all historical frame data of the vehicle; and shrink the comprehensive left and right boundaries inwards according to the comprehensive confidence weight to obtain the left and right positions of the license plate The preset pixel expansion amount expands up and down the y-axis pixel value of the triggered laser scanning line on the snapped photo to obtain the upper and lower positions of the license plate in the snapped photo, thereby obtaining the license plate position area. The device is realized based on the above method. The invention can accurately locate the position of the license plate; and the positioning of the license plate is not affected by light conditions such as the license plate facing light and backlight.

Description

technical field [0001] The invention relates to the technical field of multi-lane free flow, in particular to a laser-based license plate positioning method, device and system. Background technique [0002] Multi-Lane Free Flow (MLFF) technology is widely used in urban congestion charging, urban road and bridge charging and other fields. In today's increasingly congested urban traffic and increasingly serious air pollution, the importance of MLFF technology has become increasingly prominent. [0003] MLFF usually requires an information interaction system based on vehicle-road communication. When a vehicle equipped with an Onboard Unit (OBU) passes through the control area, the MLFF roadside equipment and the OBU will exchange information after safety certification, and complete the transaction to form a transaction record. At the same time, the vehicle positioning device completes the vehicle positioning, triggers the vehicle image capture device to capture and identify t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06K9/32G06K9/62
CPCG06V10/25G06V20/625G06F18/253
Inventor 陈偲房颜明胡攀攀李娟娟
Owner BEIJING WANJI TECH