564
edits
Biomod/2014/Kansai/Project: Difference between revisions
From OpenWetWare
Jump to navigationJump to search
→What's QR code
No edit summary |
|||
| Line 54: | Line 54: | ||
=What's QR code= | =What's QR code= | ||
<div style="text-align:justify;"> | <div style="text-align:justify;"> | ||
QR code | QR code (Quick Response Code) is two-dimensional barcode first designed in Japan. The QR code system was invented in 1994 by Denso Wave. A barcode is a machine-readable label that contains information. A QR code uses four modes (numeric, alphanumeric, byte / binary and kanji) to efficiently store data; extensions may also be used. The QR Code system has become popular outside the automotive industry due to its fast readability and greater storage capacity compared to barcodes. Recently, you find it out many places, for example, snack packages, plastic bottle’s labels and a scientific paper. Applications include product tracking, item identification, time tracking, document management, general marketing, and much more. A QR code consists of black square dots arranged in a square grid on a white background, which can be read by an imaging device (such as a camera). | ||
<br> | |||
[[Image:Pfig1.pdf|center|300px]]<br><br><br> | [[Image:Pfig1.pdf|center|300px]]<br><br><br> | ||
<br> | |||
=Design of QR code= | |||
A QR code is detected by a 2-dimensional digital image sensor and then digitally analyzed by a programmed processor. The processor locates the three distinctive squares at the corners of the QR code image, using a smaller square (or multiple squares) near the fourth corner to normalize the image for size, orientation, and angle of viewing. The small dots throughout the QR code are then converted to binary numbers and validated with an error-correcting code.<br> | |||
This is made | |||
The amount of data that can be stored in QR code depends on the datatype and version (1, …,40), and error correction level. QR code (version 1, error correction level) we used as reference can store 152 number of data bits, 25 alphanumerics, 41 numbers and 10 chinese characters. | |||
QR code we used as reference is simple in all versions. This is made of 21 cells × 21 cells.<br> | |||
[[Image:Pfig3.png|center|150px]]<br> | [[Image:Pfig3.png|center|150px]]<br> | ||
[[Image:StatusQRver1.png|center|450px]]<br> | [[Image:StatusQRver1.png|center|450px]]<br> | ||
The | Codewords are 8 bits long and use the Reed–Solomon error correction algorithm with four error correction levels. The higher the error correction level, the less storage capacity. The following table lists the approximate error correction capability at each of the four levels.<br> | ||
[[Image:Pfig4.png|center|500px]] | [[Image:Pfig4.png|center|500px]] | ||
<FONT COLOR="#000080" SIZE="5"> | <FONT COLOR="#000080" SIZE="5"> | ||
