Principle introduction
1. About the principle of barcode
Barcode applications can be seen everywhere in life. When you go to the supermarket to buy goods, almost every product will have a corresponding barcode. This is a pattern consisting of black and white stripes, where the black parts are called "strips" and the white ones are called "empties". Bars and spaces are used to represent 0 or 1 respectively. The combination of stripes of different thicknesses forms different coded information. Using binary encoding, numbers, characters and symbolic information can be represented.
Barcodes require the use of specialized equipment for identification, namely a scanner gun. The bars and spaces in the barcode have different reflectivities for the same light, and their respective reflected light intensities are also different. The barcode scanner uses this principle to detect different reflected lights from different emission areas through optical sensors to identify barcodes. Barcode labels can be printed on ordinary paper or on special label paper.
2. About the principle of QR code
With the advancement of technology, QR codes are gradually becoming known to the public. Nowadays, the QR code information of Alipay and WeChat payment can be seen everywhere, which has indeed made people’s lives more convenient. Earlier we talked about QR codes in visual recognition:
QR codes are considered to be one of the alternatives to one-dimensional barcodes. One-dimensional barcodes are mainly composed of black and white stripes. There is a sequence of English letters or Arabic numerals below the stripes. They are mainly used to store product information.
The QR code is usually a square structure in the form of a dot matrix. It uses black and white geometric figures to record data symbol information. It is a specific geometric figure distributed on a plane according to certain rules. Since QR codes store information both horizontally and vertically, compared with one-dimensional barcodes, they have a larger amount of information storage and the barcode occupies a smaller area.
The information recorded in the QR code can be automatically identified and read through an image input device or an image scanning device. One-dimensional barcodes can record the basic information of a product, but cannot provide detailed information about the product. If necessary, we need to query the detailed information of the corresponding barcode through the database. The QR code can view the detailed information of the product without the need for a database, which is simple and convenient.
3. About the principles of RFID
RFID is different from barcodes and QR codes. Both barcodes and QR codes can be thought of as patterns printed on pieces of paper, encoded in black and white bars or black and white grids on the pattern, without chips. RFID is an electronic tag, and the information is stored in the chip, which can be read and written. The printer used is also a specialized printer capable of writing information on the chip.
RFID technology is a radio frequency automatic identification technology that can carry out mobile identification of any item, track all aspects of the item from production to the hands of consumers, and record the logistics information of the product.
RFID radio frequency identification is a non-contact automatic identification technology. It automatically identifies target objects and obtains relevant data through radio frequency signals. The identification work does not require manual intervention and can work in various harsh environments. An RFID system is mainly composed of electronic tags, antennas, readers, middleware and hosts.
The basic working principle of RFID technology is not complicated: after the tag enters the magnetic field, it receives the radio frequency signal from the reader and uses the energy obtained from the induced current to send out the product information stored in the chip, or actively sends a signal of a certain frequency; After the reader reads and decodes the information, it is sent to the central information system for relevant data processing.
There are three major categories of RFID technology products: passive RFID products, active RFID products, and semi-active RFID products. Passive RFID products do not have batteries, while active RFID products and semi-active RFID products have batteries. Semi-active RFID products have small batteries and rely on their own battery energy to maintain the activated state when not communicating with the reader.
Comparison of application features
1.Characteristics of barcodes
Barcodes can be used to represent numbers, English and symbols, but not Chinese characters. It only records information horizontally, but does not record information vertically, and has certain anti-destruction capabilities. If a part is destroyed vertically, as long as the horizontal direction is intact, the corresponding information can be read.
Fast barcode input: Compared with keyboard input, barcode input is 5 times faster than keyboard input. Barcodes scan faster than QR codes.
Barcode labels are easy to make, if they don’t need to be adhered, plain paper will do, and scanning equipment is relatively cheap.
Barcodes can be used in material management, production management, supermarkets and other fields.
2. Characteristics of QR code
Compared with barcodes, QR codes can represent Chinese characters, which is a major advantage. Its representation of information is also higher than that of barcodes. Traditional barcodes can only handle about 20 digits of information. In comparison, QR codes can handle dozens to hundreds of times the amount of information of barcodes.
QR codes are also easy to scan with mobile phones, which makes mobile payments very common. Today when we buy things in the market, almost all payments can be completed by scanning the payment QR code.
QR codes also have certain error correction capabilities, up to about 30% error correction, and the information can be read even with a small amount of damage.
QR codes can be read quickly from any direction. The secret lies in its three positioning patterns, which can help the QR code not be affected by the background style and achieve fast and stable reading.
3.Characteristics of RFID
Regardless of barcode or QR code, only one tag content can be read at a time. With RFID technology, multiple tags can be read at a time, and the reading efficiency is greatly improved. This is an advantage of RFID, and because of this advantage, it is used in many applications. Occasion replaces barcode.
RFID technology has the advantages of high anti-counterfeiting and information control. In the process of using RFID, it can effectively reduce the cost of goods and effectively control the generation of counterfeit and shoddy goods. Therefore, RFID tags are indispensable identification tags for items entering the Internet of Things.
RFID has different frequencies. From the working frequency band, it can be divided into low frequency (125Khz~134Khz), high frequency (13.56Mhz), ultra high frequency (860MHz~928Mhz, different standards around the world), microwave (2.45Ghz, 5.8Ghz ). The higher the frequency, the farther the propagation distance, but the diffraction or penetration ability is weaker.
RFID tags can repeatedly add, modify, and delete the data stored in the RFID tag to facilitate information updates.
When covered, RFID can penetrate non-metallic or non-transparent materials such as paper, wood and plastic, and can communicate penetratingly. Barcode scanning equipment must be at a close distance and not blocked by objects before it can read barcodes.
Comments
0