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How do QR Codes Work?

These days, it is not uncommon to find a QR code in newspaper advertisements, on home delivery goods or even food items. What are these QR codes? How do they work? Well, let's decode the QR code and find out for ourselves.
Did you know that even though the demand for a QR code (quick response code) has gained popularity in recent years, it has actually been in use for more than a decade? The QR code was generated in the year 1994, by (a global automotive components manufacturer) DENSO WAVE, a subsidiary of the Toyota Group of companies.
With technology playing a major role in our daily lives, it is not surprising to spot a QR code even while walking down the street with a newspaper in hand. What do you do if you want to download an application for your new phone, or order a pizza? Simple - run your smartphone over the QR code and you have it scanned and decoded in minutes.

What is a QR Code

A QR code is a type of matrix barcode, which is also known as a 2-dimensional (2-D) code. It was first designed to keep a track of manufactured automobile parts; however, its use outside the automotive industry has seen a steady rise in the past few years.
The QR code has surpassed the usage of the standard UPC barcode, owing its credit to an extensive storage capacity and an incredibly fast readability.

Components of a QR Code

The code is made up of a number of black and white modules, which are arranged in a regular polygon (or in simpler words, a square). A standard QR code can contain a whopping 7k characters.
The components of a QR code include four standardized modes of data, which include alphanumeric, numeric, binary and Kanji data. Refer to the table given below for a detailed information of the QR code.

Structure of QR Code

How do QR Code Generators Work?

The QR code generator translates data into a QR code. The amount of data that can be stored on a QR code depends on the mode (input data type), the dimension of the symbol and the four error correction levels.
The QR code generator is a built-in system that places data in a zigzag pattern, which is then filled with alignment patterns and interleaved error-correction blocks that complicate the QR code.
The QR code generator translates data into octets (8 bits long) and the number of bits in the length field vary depending on the encoding and the version that is used.
           Working of a QR Code Generator
Types of Encoding Bits No. of Characters
Numeric encoding 10 bits per 3 digits
Alphanumeric encoding 11 bits per 2 characters
Byte encoding 8 bits per character
Kanji encoding 13 bits per character
The QR code uses the Reed-Solomon (RS) code, which can automatically correct up to 15 errors per block, thus limiting the complexity of the decoding algorithm. The four levels of this code are:

⇨ Level L , which can automatically restore 7% of the codewords
Level M , which can automatically restore 15% of the codewords
Level Q , which can automatically restore 25% of the codewords
Level H , which can automatically restore 30% of the codewords
Most of these QR code generators are available online; all you've got to do is, enter the data to be translated and it will generate the code, which can either be printed or scanned on to an electronic device.

How do QR Code Readers Work?

Decoding information is now a mere child's play, as you do not need special scanners to interpret the QR code. All you've got to do is, scan the QR code with the inbuilt camera on your cell phone.
Your cell phone will convert the picture of the code into a text format, which can be read after you have already installed a software that will interpret the code for you. Once your phone has processed the information on the QR code, you can decipher the text or image that was embedded into the QR code.
QR code generators are an ingenious scheme that allow the code to be read in any orientation, which means you can read the information, even if a part of the code is damaged.
Seeing the way the QR code works, it makes it relatively easier to use and understand. Considering that it can be used both in the print media as well as in the electronic media, its usability has seen an upward trend.
It won't be long before you can use QR codes in educational streams, where all you would have to do is, scan the QR code and gain access to all that you need to know in the course structure.
When it comes to using QR codes creatively, there is no stopping the creativity that can flow. QR codes can be creatively used to market your product or as a style statement on your tee; you just need to put your thinking hats on!

 Cheryl Mascarenhas

Markus Winkler, Albert Hu