To convert the bar code compiled according to certain rules into meaningful information, it needs to go through two processes: scanning and decoding. The color of an object is determined by the type of light it reflects. White objects can reflect various wavelengths of visible light, while black objects absorb various wavelengths of visible light.

Therefore, when the light emitted by the light source in barcode scanner is reflected on the bar code, the reflected light shines on the photoelectric converter inside barcode scanner, and the photoelectric converter converts the reflected light signal into corresponding electrical signals according to the different intensities.

Bar code technology has the following advantages.

1. Fast input speed: Compared with keyboard input, bar code input speed is five times that of keyboard input, which can realize "instant data input".

2. High reliability: the error rate of keyboard input data is 300%, the error rate of optical character recognition technology is110000, and the error rate of barcode technology is less than110000.

3. The amount of information collected is large: the traditional one-dimensional bar code can collect dozens of characters at a time, and the two-dimensional bar code can carry thousands of characters, which has certain automatic error correction ability.