WiFi QR Code is to WiFi account password you enter are coded according to certain rules in the plane (two dimensions) distribution with a specific geometric pattern of black and white. In modern life, it is widely used.
Sample QR Code application
Monochrome - Right Angle
Monochrome - Liquid
Monochrome - rounded corners
Color - Right Angle
Tri-color - liquid
Four-color - rounded corners
Identify the problem
Standard (square) QR Code
The two colors of black and white,With rectangles graphics,Simple, easy to identify
Liquid QR Code
The rectangle angle processing,Smoothed,Recognition rate is not high
Rounded corners QR Code
The angle of the filling process,Smoothed,Recognition rate is not high
Color QR Code
The more variety of color composition,Beautiful, image,Recognition rate is not high
The principle of QR Code
The principle of QR Code from the principle as a two-dimensional matrix code and QR Code to tell determinant.
Matrix QR Code (also known as QR Code checker) is in a rectangular space with black and white pixels in the matrix are encoded with different distributions.
The figure is highly reliable information will pop up after two-dimensional matrix commonly used code examples, phone normal scan: position in the matrix elements appear square dots, dots or other shapes dot represents a binary "1", the point does not appear represents a binary "0", permutations and combinations point to determine the significance of the two-dimensional matrix code represents.
Matrix QR Code is based on computer image processing technology, a combination of coding theory and other graphical symbols automatically read a new process based on the code system.
Representative Matrix QR Code has: Code One, Maxi Code, QR Code, Data Matrix and so on.
The figure of the matrix, black and white areas are specified in the QR code specification for fixed position, called the finder pattern and timingpattern.
Viewfinder graphics and positioning of graphics to help decode the specific program to determine the coordinates of the graphic symbol.
Yellow area is used to save the contents of the encoded data and error correction information code. Blue area to identify the level of error correction (ie Level L to Level H) and the so-called "Mask pattern", this area is called the "format information".
Row row principle
Row row QR Code (also known as: stacked QR Code or QR Code layer row) encoding principle is based on the one-QR Code basis, as needed piled into two or more lines.
It inherited some characteristics of one-QR Code in code design, verification principle, reading methods, reading equipment and bar code printing technology is compatible with the one-QR Code.
However, due to the increased number of lines, lines need to be judged, the decoding algorithm and software are not identical to the one-QR Code.
Representative row exclusive QR Code has CODE49, CODE 16K, PDF417 and so on.
Where CODE49, was in 1987 by Dr. David Allair research, Intermec has introduced the first QR Code.
QR Code fault rate
QR Code is fault tolerant, when the QR Code image is blocked by a part, you can still scan it. Principle of fault tolerance is a QR Code in the encoding process was redundant, like the 123 is encoded as 123123, so long as the QR Code scanning to a portion of the picture, QR Code can be read all the contents still. QR Code which means the QR Code after the fault rate is the number of block icons, it can still be scanned capacity. Fault rate is higher, the more the QR Code image can be blocked part.
QR Code printing instructions
Information contained in the QR Code is too long, leading to sweep the QR Code recognition does not come out too low, the number of QR Code word text of the recommendation is no more than 150 words (the low end of the phone can scan), after the QR Code beautification foreground and background colors are too close will result in a QR Code can not be scanned. Web site pages do not support QR Code mobile scanning. The media distortion or reflective QR Code printing software does not recognize the result scan code