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uick response code, or QR code in short, is a special bar code that is usually displayed as a matrix of black modules arranged in a square pattern (data codes) and used to store data in a secured manner. These patterns can be read by using QR code readers that can be downloaded on mobile phones that have a camera (for scanning the code) and a pre-activated general packet radio service (GPRS) setting. (GPRS is used to browse the Internet on mobile phones.)
lnce the QR reader on the mobile phone is launched, the program activates the camera on the device. When the mobile is brought near the code and the code is focused between the black squares (three large and one small), the data gets displayed on the screen.
The QR code follows the ReedSolomon error-correction algorithm and hence is less susceptible to errors as it follows parity check. The encoded information can be made up of four modes of data: numeric, alphanumeric, byte/binary and hanji.
7KH 45 FRGH wDs fiUsW GHsLJQHG for the automotive industry. Now QR codes are used everywhere starting from products to webpages, advertising, mobile money transactions and goods inventories. Storing URLs, these can be found on magazines, buses and business cards. These have even found applications in Google-powered Android smart phones.
Presented here is a QR code generator interface. The software code written in gavaScript generates HTML QR codes upon feeding the data. Up to 7089 characters (0-9) Up to 4296 characters (0-9, A-Z uppercase, space, $, %, *, +, -, /, :) Up to 2953 characters (8-bit bytes) Up to 1817 characters
Table I shows how much information you can store in just one QR code symbol.
The QR code matrix depicted in the program can generate a 33x33 matrix truncated to S0 characters only. The code word so generated is 8-bit long and uses Reed-Solomon error-correcting coding technique with four levels of error correction: Level L (T per cent), M (15 per cent), Q (O5 per cent) and H (T0 per cent). The percentages in brackets indicate the restoration factor. (For further details of the Reed-Solomon error-correction coding technique, visit http://en.wikipedia.org/wiki/ReedSolomon_error_correction page.)
The alphanumeric characters and their corresponding codes are given in Table II.
Fig. 1 depicts the structure of a QR code. Fig. O shows the various versions.
The program
The program QR_33.htm is coded in gavaScript language to generate mask patterns and data patterns. The QR pattern is obtained by using the data that has to be encoded. The program generates a data matrix of 8-bit length scattered over a square area of 33 blocks vertical and 33 blocks horizonWDO. 0RGHs DUH WKHQ GHfiQHG fiUsW DQG later their corresponding data matrix DUUDy. 7KH BCH FRGH Ls DOsR GHfiQHG LQ the code so that there is no parity error in the generated code.
In the next part, the four error checker units L, M, Q and H are GHfiQHG. 7KH sRuUFH FRGH KDs EHHQ explained at places where the new functions have been declared to get a quick understanding. More details on the QR code can be found at www. denso-wave.com/qrcode/qrgene3-e.