Regarding LPR (Plate) software, it is the computer program that can automatically identify car license plate numbers. Now many parking lots, toll stations, and traffic surveillance cameras use this thing, which is really convenient – you don’t need to manually mark numbers one by one, the machine can read it out and save it for you, which is a waste of time! The basic working principle of this software is to use the camera vehicle image first, and then process the image in a series of ways, such as turning the direction, cutting out the license plate area from the entire image, and then separating the characters on the license plate one by one. Finally, using an algorithm to identify whether these characters are numbers or letters, and then combining them into a complete license plate number. If the whole process is fast, it will not be used for a second.
1. Image acquisition module : You must have a high-definition camera, whether it is fixed on the pole or installed on a mobile device, you must take it clearly – you must be clear when the light is good during the day, and you must be able to take it clearly when it is dark at night. It is best to prevent backlighting, rainy days, etc. Otherwise, the image will be blurred and it will be useless to identify it later!
2. Preprocessing link : This step is like laying the foundation before "putting makeup" the image, adjusting the crooked image, removing useless things in the image, and making the license plate area more prominent. Sometimes, you have to adjust the brightness, contrast, etc. of the image to make the number clearer. Anyway, it is to make the image more suitable for machine "reading".
3. License plate positioning and extraction : The software is so sharp that it can accurately find where the license plate is from a big .car picture, and then cut out the small piece of the license plate. This step has a great impact on the recognition behind it. If the license plate is not found correctly, the ones that are recognized later must be wrong!
4. Character segmentation and recognition : further disassemble the extracted license plate pictures, and then disassemble the license plates like "Lu" into characters one by one, "A", "1", "2", "3", "4", and "5". Then, use the trained recognition model to "guess" what each character is. Now many people use deep learning methods to do this recognition, and the accuracy rate is much higher than before.
5. Results output and query : The identified license plate number will be stored in the database or displayed directly on the control screen. The manager can check information such as when the car came in, when it went out, how much parking fee was paid based on this number, and can also easily search the records of a specific license plate.
Many people will be confused about the recognition rate when choosing LPR software – if the recognition is not clear and there are always mistakes, then this software will be too annoying! Generally speaking, better LPR software can reach 99% and get up even if the light is normal, the license plate is relatively clean, and there is no obstruction! And that recognition speed is also very good! Heavy! want! Especially for parking lots with many cars, license plates come one by one, and the software must respond quickly, otherwise it will be blocked. Generally, the processing speed of milliseconds is enough.
In addition, it is necessary to see whether this software supports multiple license plate types – our country has blue, yellow, green license plates (new energy license plates), and special license plates such as police cars and armed police. It is best to recognize them all, otherwise it is not possible to stop when you encounter a rare license plate. Compatibility is also a matter of whether you can connect with parking lot systems, access control systems, charging systems, etc., and whether you will require a lot of hardware to be replaced. These must be considered and provide global procurement services for weak current intelligent products! Can help you save some fun.
Q: There are so many LPR software on the market, the price difference is very big and the price is hundreds of yuan, and the price is tens of thousands, how to choose
A: Well… the truth is sometimes the same! Useful! Cheaper may be a basic recognition function. The recognition rate is not stable enough, and the adaptability to complex environments is poor, and after-sales service may not keep up. The expensive ones generally have more complete functions, such as being able to identify the color of license plates and supporting more language license plates (although it is mainly used in Chinese and English in China), providing more complete data analysis and reporting functions, and technical support is relatively in place, and may also include regular algorithm upgrade and update services – so it depends on what you use it specifically. Use it for a small parking lot by yourself, and maybe a few thousand yuan is enough. If it is used by a large commercial complex or a traffic management department, you still have to choose a reliable and stable big brand that is more expensive.
Q: Then can I use the mobile app to build a simple LPR system?
A: In theory…it seems…it's OK? Now some mobile phones have high pixels, and some open source LPR codes can be downloaded and tried by yourself. If you tinker with maybe for a long time, you can also achieve a simple recognition, but! Reliability and stability are definitely not as good as professional software and hardware equipment combinations. Moreover, the angle and light are uncertain when taking pictures of mobile phones, and the value is not too great. If you really want to use it seriously, it is recommended to buy a complete set and mature solution!
If you want me to say that when choosing LPR software, the most important thing is to first figure out what your needs are, how many cars you need to identify every day, how high the requirements for speed and how much budget you have, and then compare the products – it is best to find a manufacturer to try a demo version, let them use the actual environment and vehicle pictures of your place to see how the effect is. Don’t just listen to them blowing around, actual testing is the king!
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