"In particular, for the first time, a bar code used to record the information of issuing driver's licenses was added to the card core. In the future, the new driver's license will be digitally managed. This bar code consisting of 13 digits will play a great role in the management of driving license and traffic order.
The first two digits of the bar code represent the province, the third digit is the check digit, and the last ten digits are the serial number. Each driver's license has a separate number.
If someone loses his driver's license, after applying for a new driver's license through normal procedures, the number occupied by the old driver's license will be marked as invalid. Even if the old driver's license is not printed with the word "invalid", it has actually been marked as invalid by barcode, and the new driver's license will get a new number.
In the past, some drivers applied for a new license because they could not find a driver's license. After finding the original license, there may be a phenomenon that the two licenses are used alternately.
There are also some drivers who deliberately apply for new driver's licenses and use them with two licenses, which interferes with traffic management. Now with the digital management technology of bar code, drivers can effectively prevent the behavior of holding double or multiple licenses.
The frontline police found suspicious driver's license in management, and we can accurately judge which driver's license is valid by barcode.
Another function of the bar code is that the Ministry of Public Security will put on record each certificate core, and once a false certificate appears, it will be traced back through the bar code.
Identification principle:
The widths of white bars and black bars are different, and the duration of corresponding electrical signals is also different.
However, the electrical signal corresponding to the bar code output by photoelectric converter is generally only about 10mV, so it cannot be used directly. Therefore, the electrical signal output by the photoelectric converter should be sent to the amplifier for amplification first.
The amplified electrical signal is still analog. In order to avoid false signals caused by defects and stains in bar codes, it is necessary to add a shaping circuit after the amplification circuit to convert analog signals into digital electrical signals so that the computer system can accurately interpret them.
The pulse digital signal of the shaping circuit is converted into digital and character information by the decoder.
It can distinguish the coding system and scanning direction of bar code symbols by identifying the start character and the end character. The number of stripes and spaces can be determined by measuring the number of pulse digital electrical signal 0, 1, and the width of stripes and spaces can be determined by measuring the duration of signal 0, 1.
In this way, the number of bars and spaces of bar code symbols, the corresponding widths and the coding system used are obtained. According to the coding rules corresponding to the coding system, bar code symbols can be converted into corresponding digital and text information, and sent to the computer system for data processing and management through the interface circuit, thus completing the whole process of bar code recognition and reading.
References:
Bar code recognition principle-Baidu Encyclopedia