The principle of barcode recognition

To convert the barcode compiled according to specific rules into meaningful information, it needs to go through two scanning and decoding processes. The color of an object is determined by the type of reflected light. White objects can reflect visible light of various wavelengths, and black objects absorb visible light of multiple wavelengths. Therefore, when the light emitted by the barcode scanner light source is reflected on the barcode, the reflected light The photoelectric converter is irradiated on the photoelectric converter inside the barcode scanner, and the photoelectric converter converts the reflected light signal into the corresponding electrical signal according to the intensity of the reflected light signal. 

According to the difference in principle, barcode scanners can be divided into three types: light pen, CCD, and laser. After the electrical signal is output to the amplification circuit of the barcode scanner to enhance the signal, it is sent to the shaping circuit to convert the analog signal into a digital signal. The widths of the white and black bars are different, and the corresponding electrical signal durations are also different. The decoder then discriminates the number of bars and spaces by measuring the number of 0s and 1s in the pulsed digital electrical signal. The width of bars and spaces is determined by measuring the duration of the 0,1 signal. The data obtained at this time is still disorganized. To know the information contained in the barcode, it is necessary to replace the bar symbol with the corresponding number and character information according to the corresponding coding rules (for example EAN-8 code). Finally, the computer system performs data processing and management, and the detailed information of the item is identified. Finally, the computer system performs data processing and management, and the detailed information of the item is identified.