"Please scan the QR code", do you often hear or see these words?
Nowadays, QR codes have penetrated into all aspects of life, such as paying when shopping, registering identities in scenarios such as public transportation, event tickets, and conferences, or adding WeChat friends and following official accounts.
What is a QR code
A QR code is a matrix barcode that is used to store information. QR codes are usually made up of black and white squares, and their arrangement and color make up a way of encoding that can be quickly read by scanning devices such as smartphones or scanners.
Compared with one-dimensional barcodes, QR codes have the advantage of storing more information, larger information capacity, and high fault tolerance and high density, even if the information is partially damaged or obscured, the information can be read.
How the information is stored in a QR code
QR codes are stored in such a way that they represent different information through the arrangement of black and white pixels on a two-dimensional plane. Specifically, a QR code consists of multiple small squares (also known as modules), each of which can be white or black and represents a binary 0 or 1, which are arranged according to specific rules to form a matrix-like pattern – a two-dimensional pattern.
In a QR code, the information is encoded into a series of data. During the encoding process, a special coding algorithm is used to convert the information into binary data and map it onto the module of the QR code.
When the scanning device reads the QR code through an optical sensor, it parses the arrangement and color information of the modules and converts them into the corresponding binary data. Then, according to a specific decoding algorithm, the binary data is converted back to the original information content.
In general, the way the QR code stores information is to represent different binary data through the arrangement and color of the module, and then improve the accuracy and fault tolerance of recognition through encoding and redundant information.
When the scanning device reads the two-dimensional code, it restores the encoded information by parsing the arrangement and color of the module, so as to realize the reading of the data stored therein.
Will QR codes run out?
Nowadays, the use of QR codes is huge. According to incomplete statistics, the global use of QR codes is as high as more than 10 billion every day. So, will QR codes run out?
Theoretically, the QR code will be used up one day, the QR code size is fixed, and the number of black and white squares arranged and combined in a fixed area is limited, and when the stored data exceeds the capacity limit, it will be used up.
However, in practical applications, the capacity of QR codes is usually very large, far exceeding the amount of data we usually need to store.
Take the usual WeChat payment code as an example, the size specification is 25×25, then there are 625 small squares in this QR code matrix, in addition to some positioning, error correction and other functions of the square, there are 478 squares left, each square has black and white two colors, that is, it can form 2478 different QR codes.
Suppose 10 billion payment QR codes are used every day, and 3,650 billion are used a year, which means that it takes 2.1×41131 years to use up all payment QR codes, and the universe has been born for 13.7 billion years, that is, 137×1010 years, so there is no need to worry about the QR code being used up at all.
Source: China Gansu Net
