How on earth is QR code recognized? How does the black and white cube store data?

Fri Jan 06 09:24:36 CST 2023

What is a QR code?

Quick Response Code, short for QR code. Originally invented by a Japanese company, it was approved for standardization by the international standardization organization ISO. The two-dimensional code is stronger than the barcode data representation ability and stronger error correction ability. So, to put it simply, two-dimensional code is a kind of coding, we want to pass the data to be encoded and converted into another form of presentation.

Version of QR code

The QR code has 40 sizes. The official name is Version. Version 1 is the 21 x 21 matrix, Version 2 is the 25 x 25 matrix, and Version 3 is the size of 29. Each additional Version increases the size of 4.

The formula is: (V-1)*4 + 21 (V is the version number)

The highest Version 40, (40-1)*4+21 = 177, so the largest is 177 x 177 square. Each version has a maximum capacity, depending on the mode used and the level of error correction.

Maximum capacity of QR code (under Version 40-L, L is the lowest error correction level)

The number is encoded in 7089 characters

Character encoding 4296 characters

Byte encoding 2953 characters

The Japanese code consists of 1817 characters