Principles of barcodes:

1. Recognition principles

To convert barcodes compiled according to certain rules into meaningful information, scanning and translation are required. Two processes of coding. The color of an object is determined by the type of light it reflects. White objects can reflect visible light of various wavelengths, while black objects absorb visible light of various barcode production wavelengths. Therefore, when the light emitted by the barcode scanner light source is reflected on the barcode, The reflected light irradiates the photoelectric converter inside the barcode scanner, and the photoelectric converter converts the reflected light signals of different strengths into corresponding electrical signals. According to differences in principles, scanners can be divided into four types: light pen, red light CCD, laser, and image. The electrical signal is output to the amplifier circuit of the barcode scanner to enhance the signal, and then sent to the shaping circuit to convert the analog signal into a digital signal. The width of the white bars and black bars is different, and the duration of the corresponding electrical signals is also different. The main function is to prevent the quiet zone from being insufficiently wide. The decoder then determines the number of bars and spaces by measuring the number of 0,1 pulse digital electrical signals. 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 messy. To know the information contained in the barcode, you need to replace the barcode with the corresponding numbers and character information according to the corresponding encoding rules (for example: EAN-8 code). Finally, the details of the item are identified through data processing and management by a computer system.

2. Scanning Principle

Scanning barcodes requires a scanner. The scanner uses its own light source to illuminate the barcode, and then uses a photoelectric converter to receive the reflected light and convert the light and dark of the reflected light into digital signal. No matter what rule is used to print the barcode, it is composed of a quiet zone, a start character, a data character and a stop character. Some barcodes also have check characters between the data characters and the terminating character.