Nowadays, with the widespread popularity of smart phones,
QR codes have penetrated deeply into our lives
Making friends, traveling, paying... it can be said to be everywhere!
According to WeChat data in May,
During the epidemic alone, WeChat used 140 billion QR codes!
It can be said that you can travel all over the world with a QR code in your hand without fear.
Then some students must have asked:
If QR codes continue to be used like this, will they be used up one day?
In fact, the answer is very simple: yes
But it will take billions, billions...years
And if you want to know the answer,
Let’s start with the principle of QR code~
How is the QR code recognized
QR code uses specific geometric figures distributed in two dimensions according to arrangement rules, and uses black and white graphics to record data symbol information. In the eyes of the recognition program, the white square of the QR code represents the binary "0", and the black square represents the binary "1". In this way, the information contained in the QR code can be interpreted based on the color and arrangement.
The most commonly used QR code today is the QR code invented by Denso in 1994. QR is the abbreviation of English Quick Response. As the name suggests, QR code has the characteristics of being quickly recognized.
At the same time, the characteristics of QR codes also include good confidentiality, low production cost, large capacity, and wide coding range. The most important thing is that the QR code itself has an error correction function. Sometimes even if the QR code is partially damaged, it can still be correctly recognized.
Will the QR code be scanned
The current QR code has 40 official versions, Version1-40, with a minimum of 21*21 and a maximum of 177*177 matrix. Taking the 25X25 matrix payment code used by WeChat as an example, each row has 25 squares and a total of 25 columns. After excluding the positioning squares and redundant error correction squares, there are still 478 squares left.
According to the binary system, each square has two choices: black and white, so 478 small squares can theoretically combine a total of 2^478 QR codes. That is, a 25X25 QR code can be generated:
780437137578998057845399307448291576437149535666242787714789239906342934704941405030076525765872992789956732780351655723861 993919822071326572544 QR codes.
Xiaoyi made a rough estimate. Even if the number of two-dimensional objects used every year is measured in trillions, it would be enough to last for billions of trillions of trillions of years! You must know that the estimated age of the earth is only about 4.55 billion years~
Will the QR code be repeated
The QR code image is complex, and few people deliberately compare the patterns of two different QR codes. This involves a question: Will the QR code be repeated?
The answer is: not really! Because the QR code is a kind of encoding, it is generated based on the information you provide. Therefore, if you use different information when generating the QR code, the final QR code will not be the same.
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