License plate comparison method and device
A technology of license plate and license plate area, which is applied in the fields of image processing, video surveillance and security. It can solve the problems of blurred imaging, comparison errors, and low comparison accuracy, and achieve the effect of improving accuracy.
Active Publication Date: 2018-03-30
BEIJING ICETECH SCI & TECH CO LTD +1
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Problems solved by technology
[0003] The current license plate comparison system needs to achieve a high recognition rate under the condition of proper lighting and clear license plate writing. In actual scenarios, license plate character recognition errors are often caused by license plate defacement, blurred imaging, and license plate occlusion. or misalignment
In order to solve the above problems, the method of fuzzy license plate comparison is usually used to solve the problem. However, the comparison accuracy of the existing license plate fuzzy comparison method is low, especially when there are similar license plates, it is easy to cause comparison error results.
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no. 1 example
[0101] Further, the first embodiment of the block entrance license plate gradient map acquisition module 5 includes:
[0102] The optimal perspective transformation parameter acquisition module 51 is used to randomly select 4 matching points as the i-th group of perspective transformation points P i , get the corresponding perspective transformation parameter A i , and then use all matching points to verify the perspective transformation parameters, and count the number SUM that conforms to the perspective transformation parameters i , select SUM i Perspective transformation parameter A with the largest value i as the optimal perspective transformation parameter;
[0103] Entrance license plate perspective transformation diagram acquisition module 52, used to perform perspective transformation processing on the entrance license plate area image according to the optimal perspective transformation parameters, and obtain the perspective transformation diagram of the entrance l...
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The invention provides a license plate comparison method. The license plate comparison method includes the steps of respectively acquiring the feature points of an entrance license plate area and an exit license plate area using a feature extraction method based on corner detection; acquiring a matching point using feature point matching algorithm; getting the location of each character in the exit license plate area, conducting character partition for the exit license plate area and calculating the gradient map of the partitioned exit license plate area; acquiring optimal perspective transformation parameters, the perspective transformation diagram of entrance license plates and the perspective transformation diagram of the partitioned entrance license plates, and calculating the gradientmap of the partitioned entrance license plates; calculating the correlation coefficient between the gradient map of the exit license plate area of each partition and the gradient map of the perspective transformation diagram of the partitioned entrance license plates, calculating the accumulated value of the correlation coefficients of all partitions as the score of the comparison to be output. Compared with the prior art, the license plate comparison method has the advantages of effectively achieving the comparison of fouling, blurring, blocked and the like license plates.
Description
technical field [0001] The invention relates to image processing, video monitoring and security protection, in particular to a license plate comparison method and device. Background technique [0002] With the increasing modernization of cities, the number of motor vehicles continues to increase, and intelligent transportation systems are playing an increasingly important role. License plate comparison technology is an important part of modern intelligent transportation systems and has a wide range of applications. [0003] The current license plate comparison system needs to achieve a high recognition rate under the condition of proper lighting and clear license plate writing. In actual scenarios, license plate character recognition errors are often caused by license plate defacement, blurred imaging, and license plate occlusion. or misalignment issues. In order to solve the above problems, the method of fuzzy license plate comparison is usually used to solve the problem....
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IPC IPC(8): G06K9/62G06K9/34G06K9/46
CPCG06V30/153G06V10/40G06V10/757G06V20/625
Inventor 班华忠杨振杰尹方始李党
Owner BEIJING ICETECH SCI & TECH CO LTD