The definition and classification of two-dimensional code

The definition of two-dimensional bar code

2D barcode refers to a readable barcode expanded from 1D barcode. It uses black and white rectangular pattern to represent binary data, and the information contained in it can be obtained after being scanned by the device. The width of a one-dimensional bar code records the data, while its length does not. The length and width of a two-dimensional bar code record data. 2D barcode has "anchor point" and "fault tolerance mechanism" which 1D barcode does not have. The FAULT TOLERANCE MECHANISM CAN RESTORE THE INFORMATION ON THE BAR CODE CORRECTLY EVEN IF NOT ALL OF THE BAR CODE IS IDENTIFIED, OR if the BAR code is stained.

A QR code usually has three anchor points, which provide reader identification. Because of these anchor points, the QR code can be identified no matter what direction it is read from. Two-dimensional code records more data than one-dimensional bar code. And it can record more complex data, such as pictures, web links and so on.

Classification of two-dimensional code

Two-dimensional code can be divided into stacked/row type two-dimensional bar code and matrix type two-dimensional bar code. In the form of stacked/row row 2D barcode, it is stacked by multiple rows of truncated 1D barcode. Matrix 2D barcode is composed in the form of a matrix. In the corresponding element position of the matrix, "point" is used to represent binary "1", and "empty" is used to represent binary "0". The code is composed of the arrangement of "point" and "empty".

Stacked two-dimensional bar code

Stacked/row 2D barcode (also known as stacked 2D barcode or layer row 2D barcode), its coding principle is built on the basis of one-dimensional barcode and stacked into two or more lines as required. It inherits some characteristics of 1D barcode in coding design, verification principle, reading mode and so on. The reading equipment is compatible with barcode printing and 1D barcode technology. However, due to the increase of the number of lines, it is necessary to determine the lines, and its decoding algorithm and software are not exactly the same as one-dimensional bar code. Representative two-dimensional bar codes of row type include: Code 16K, Code 49, PDF417, etc.

Matrix two-dimensional bar code

Short matrix 2D barcode (also known as checkerboard 2D barcode) it is encoded in a rectangular space by the different distribution of black and white pixels in the matrix. In the position of the corresponding elements of the matrix, the appearance of points (square points, round points or other shapes) represents the binary "1", and the absence of points represents the binary "0". The arrangement and combination of points determines the significance of matrix 2D barcode. Matrix 2D barcode is a new type of graphic symbol automatic reading and processing code system based on computer image processing technology and combination coding principle. Typical two-dimensional Matrix bar codes include Code One, Maxi Code, QR Code, Data Matrix, etc.

In the current dozens of two-dimensional code, commonly used code system are: PDF417 QR Code, Datamatrix QR Code, Maxicode QR Code, QR Code, Code 49, Code 16K, Code one, etc., in addition to these common QR codes, There are Vericode barcode, CP barcode, Codablock F barcode, field code, Ultracode barcode, Aztec barcode.