The QR Code

A little bit of 21st Century magic today… The QR Code.

Standing for Quick Response, this amazing device is becoming increasingly ubiquitous, appearing regularly in newspapers, magazines and posters.

Developed as long ago as the mid 90’s by a Toyota subsidiary company in Japan, the matrix barcode or two dimensional code consists of black square modules, arranged in a specific pattern on a white background.

It works by….. well that’s the thing, how on earth does it work? I open up Google Goggles on my phone, it takes a picture of the shape and then gives me the opportunity to go to a web site… I could just about get my head around bar codes, where differently thin and fat lines represent different numbers, that all seems plausible enough. But as to this…

The image to the right is from Wikipedia and begins to sort of explain what the various areas relate to in terms of information, positioning, alignment etc. but how this shape can contain text, links, URLs’ etc. within such an apparently simple arrangement of black and white squares is completely beyond me.

And as is so often these days, despite it being incomprehensible magic, you can easily get your own made up for free… The one at the top of this post is from a site called Quirify. It consists of 625 modules in a 25 x 25 grid, took less than 10 seconds to produce and contains the web address of this blog.

Try it with your Google Goggles App, it’s truly an amazing thing…

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  1. vexarb
    June 7, 2011 at 15:26

    Looks to me like a Hadamard code for analysing a picture into a 2D matrix of Black&White blocks:

    http://connect.in.com/discrete-cosine-transform/images–hadamard-transform-1-971160231394.html

    But it seems that QR, though related, is not exactly the same as Walsh Hadamard 2D block coding.

    http://books.google.com/books?id=1d3-W_KcFX4C&pg=PA88&lpg=PA88&dq=qr+code+%26+walsh+hadamard&source=bl&ots=o7v3wuYQ0L&sig=HHTuOKgvqxvDb3CI4sCSuvQT8S0&hl=en&ei=2UDuTfDOOY6a-wa-2sjxBw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCQQ6AEwAg#v=onepage&q&f=false

    Question: Does QR encode your URL as a PICTURE or as an ASCII TEXT message?

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