Supermarket barcode scanners are also commonly referred to as bar code readers. They are devices for reading information contained in bar codes and can be divided into one-dimensional and two-dimensional bar code scanners. The supermarket barcode scanner is usually made up of the following parts: a light source, a receiving device, a photoelectric conversion component, a decoding circuit, and a computer interface. The basic working principle of the scanner is that the light emitted by the light source is illuminated by the optical system onto the bar code symbol. Then the reflected light is imaged by the optical system on the photoelectric converter and interpreted by the decoder as a digital signal that the computer can directly accept. In addition to one, two-dimensional barcode scanner classification. Supermarket barcode scanner an also be classified into CCD, full-angle laser and laser handheld barcode scanner.
A bar code is a set of bar and space symbols arranged according to a certain coding rule to represent information consisting of certain characters, numbers, and symbols, which is an automatic identification system consisting of bar code symbol design, production and scanning. Barcode technology has some evident advantages.
Compared with the keyboard input, the bar code input speed is 5 times of the keyboard input, and can realize “instant data input”. What’s more, the error rate of keyboard input data is three hundredths. The error rate of using optical character recognition technology is one in ten thousand, and the bit error rate of bar code technology is less than one-millionth.
In contrast to the traditional one-dimensional bar code that can collect information of dozens of characters at a time, the two-dimensional supermarket barcode scanner can carry thousands of characters of information and has certain automatic error correction capability.
Bar code identification can be used as a means of identification alone, or it can be combined with related identification equipment to realize automatic identification, and it can also be connected with other control equipment for automatic management.
In addition, labels of supermarket barcode scanner are easy to manufacture, there are no special requirements for equipment and materials because identification equipment is easy to operate, not requiring special training.
One of the early handheld touch bar readers is a light pen, which is also the most economical bar code reader. When in use, the operator needs to touch the stylus on the surface of the bar code, then the lens of the stylus emits a small spot of light. When the spot is swiped from left to right, the light is reflected in the “empty” part. In the strip part, the light will be absorbed, so a varying voltage is generated inside the light pen. This voltage is amplified and shaped for decoding afterward.
The supermarket barcode scanner has no moving parts inside, which is cheaper than other readers and has the advantage of the unlimited length of the reading bar code. It is relatively strong and small in size and light in weight. Apart from that, it has some disadvantages like restrictions in certain circumstances, such as the inability to access the bar code in some cases. The stylus can only function when reading a bar of a specified density with better print quality on a relatively flat surface. What’s more, the operator needs to be trained to use it. For example, reading speed, reading angle, and improper use of the pressure will affect its reading performance. Finally, when the protective film is layered, the light pen cannot be used; the light pen has a low first reading success rate and a high bit error rate.