Recently, I went to a conference where every person had a name tag,on the bottom of the tag was their own personalized QR Code which stored the email id of the person.Before,going to any of the sessions the staff would scan their code and the person would receive an email at the end of the day that presented the list of all the places they went during the conference.Pretty Amazing!! that's the flexibility of QR Code usage.
The above image also known as QR(Quality Response) Code or a matrix bar-code was discovered in 1994 by Denso Wave for Japanese Automotive Industry mainly to track vehicles during manufacturing by using component scanning.The idea behind the code was to create a square grid with white background and assembly of black boxes that stored some information.The vertical and horizontal black boxes would then be interpreted by using Reed-Solomon error correction algorithm until the image was interpreted correctly.
The QR Codes mainly stores two things :-
1. Error correction level.
2. BCH Code which is named after initials of creators of this code(Bose,Chaudhari, Hocquenghem).Some of the interpretation are shown in the image below where character 0 is encoded as 00,1 as 01 ,2 as 03 and so on.
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| Alpha Numeric Character Encoding using BCH |
| Encoding | Maximum Space Allowed |
|---|---|
| Numeric Encoding | 7089 characters |
| Alpha Numeric Encoding | 4296 characters |
| Binary/byte Encoding | 2953 characters |
| Kanji/kana Encoding | 1816 characters |
Digital Encryption Algorithm also known as DES is used for encryption and decryption of QR Code.The basic working principle of this algorithm is that it takes a fixed length string and converts it into cipher text bit string by following a set of complicated operations.The DES also produces a key for decryption of the text,those who have the key can then convert the cipher text to readable string.
Nowadays users can create and customize their own codes by using tools like Adobe InDesignCC which can store some of the following information -
1.URL
2.Text ,E-mail Information, Business Cards
3.Code Payments
4.Bank account,Credit Card Information
 |
| Louis Vuitton QR Codes by Takashi Murakami |
QR Codes are supported by almost all of the operating systems like Android,Blackberry,Apple iOS,Nokia Symbian Belle.They all provide apps or default QR Code reader that can hard link information to the QR Code,an example of such reader is Google Goggles.
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| Google Goggles-App for reading QRCodes |
References
1.http://hypebeast.com/2009/4/louis-vuitton-qr-codes-by-takashi-murakami
2.http://www.enterakt.com/wp-content/uploads/2011/01/GoogleGoggles.jpg
3.http://en.wikipedia.org/wiki/Google_Goggles
4.http://en.wikipedia.org/wiki/Data_Encryption_Standard
5.http://en.wikipedia.org/wiki/BCH_code
Hi Swetha,
ReplyDeleteI was going through your blog post on QR codes. You have explained about the history and uses of these codes very well. I also learnt about the algorithms used for decoding and encoding these codes from your post. I like the fact that you have mentioned about the various encoding schemes supported. Also, the image of the QR code created by Takashi Murakami for Louis Vuitton is very interesting. Nice find! You could also include why exactly QR codes came into existence when you explain its history. For example, QR codes were created to serve the need for bar codes to hold more information. It would probably make it more interesting. You could also explain why QR codes are made of error correction level and BCH code.
Overall, great job!