What are the three squares in the QR code corner? Isn't it safe to put a logo on the scan?

First take a look at the knowledge background of the QR code:

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The two-dimensional code refers to a bar code that expands another dimension on the basis of one-dimensional code, and uses a black-and-white rectangular pattern to represent binary data, and is scanned by the device to obtain information contained therein. In fact, there are many kinds of code systems in the two-dimensional code. Now China's domestic mainstream QR code has gradually become the standard of two-dimensional code in China, including the QR code appearing on the train ticket. The QR code is from Toyota in 1994. The company Denso-Wave was created and was originally used to track vehicle parts. QR comes from the abbreviation of English "Quick Response", which is a quick response.

Take the example of the WeChat QR code of the tiger. The squares of the upper left, upper right, and lower left corners of the two-dimensional code play the role of positioning and recognition. The small squares in the black and white interlaced code contain the data content. The error rate of the QR code in the amount of information and the QR code can reach 30%, which means that the information on the bar code can be correctly restored even if all the bar codes are not recognized or the bar code is defaced.

Compared with one-dimensional barcodes, high-density encoding of two-dimensional codes, large information capacity: QR code can accommodate up to 1850 uppercase letters or 2710 digits or 1108 bytes, or more than 500 Chinese characters, than ordinary barcode information capacity It is about several times higher. In fact, this capacity can contain a lot of information, you can write a "Happy Mid-Autumn Festival" directly in the code, used to install contact information when the personal business card is also no pressure. In fact, when the QR code was first invented in 1994, the information is only stored in the QR code, but the usage of the current QR code is more based on the Internet, because its message is a link address that can be carried. More content.

QR code can become a more mainstream code system because it is a free, open coding method that everyone can use to generate QR codes.