In recent years, with the explosive development of the mobile Internet industry, the configuration of mobile phones has been continuously improved, and research on information collection, image processing, and data transmission based on mobile phone platforms has also become a hot spot, which makes it possible to recognize license plates based on mobile phone platforms. . The traditional license plate recognition system is generally based on a fixed desktop platform, and the image collection is inflexible. Especially for the traffic management department, it is very inconvenient to automatically register the license plate of the illegal vehicle. Therefore, the mobile phone license plate recognition technology based on Android and iOS platforms appears. .
So, how is the license plate recognition on the mobile phone implemented? This process is briefly described below.
Firstly, the existing license plate recognition algorithms are researched, and an algorithm suitable for running on Android and iOS platforms is found among many algorithms. First obtain the color image of the license plate through the camera of the smartphone, and then process the collected image, including grayscale by YUV model, grayscale upscaling by piecewise linear transformation, binarization, and Roberts operator for edge detection , mathematical morphology processing, etc., and then the license plate correction is performed by Hough transform, followed by the location and segmentation of the license plate by the method of double projection and grayscale jump, and finally the mobile phone license plate recognition is realized by template matching.
The process of realizing the license plate recognition on the mobile phone is as simple as the following parts:
Image Acquisition: Capture license plate images through smartphone cameras.
Preprocessing: grayscale, binarization, edge enhancement, noise filtering, automatic white balance, automatic exposure, gamma correction, contrast adjustment, etc.
License plate location: Perform row and column scanning on the grayscale image after image preprocessing, determine the license plate area, and correct the license plate inclination.
Character segmentation: After locating the license plate area in the image, through grayscale, binarization and other processing to accurately locate the character area, and then perform character segmentation according to the character size characteristics.
Character recognition: perform scaling and feature extraction on the segmented characters, and match and discriminate with the standard character expressions in the character database template.
Result output: output the result of license plate recognition in text format.
Mobile phone license plate recognition technology features
1. Just align the license plate with the camera of the smartphone or Pad, without taking pictures, to realize the function of automatically collecting the license plate information and easily scanning and identifying the license plate number.
2. The recognition rate of the whole license plate recognition on the mobile phone is as high as 99.7%, especially the recognition of Chinese characters is far ahead of similar products;
3. Fast recognition speed, extremely optimized license plate positioning and recognition algorithm;
4. Mobile phone license plate recognition supports all license plates, including blue license plate, yellow card, trailer license plate, new army license plate, police license plate, new armed police license plate, coach license plate, embassy license plate, agricultural license plate, personalized license plate, Hong Kong and Macao entry and exit license plates, Australian and Taiwan license plates, civil aviation license plates, consulate license plates, new energy license plates, etc.;
5. The license plate width requirements are low, and the license plate width is greater than or equal to 60 pixels, which does not affect the recognition;
6. The license plate recognition on the mobile phone perfectly supports the Android system, the ios system, the mobile phone ARM platform and the X86 architecture of the PDA;
7. The license plate recognition on the mobile phone supports two recognition modes: video recognition and photo recognition.
With the popularization of mobile internet and mobile terminals, OCR technology has been well applied on the mobile terminal. The mobile phone license plate recognition SDK developed based on OCR technology can directly identify and enter the license plate of the car, replacing the original manual record, and then The steps of manual entry into the computer make the identification and recording of license plates quick, convenient and accurate, which will bring great convenience to business personnel.
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