Know more on QR codes

 

QR Codes

QR code is one of the most trending technology being used to help users access certain information just with a scan using their smartphones.

QR stands for Quick Response as the codes provide information to the user instantly.

 

History of QR codes:

The QR code system was invented in 1994 by Masahiro Hara from the Japanese company Denso Wave. The initial design was influenced by the black and white pieces on a Go board. Its purpose was to track vehicles during manufacturing; it was designed to allow high-speed component scanning.

Back then, Japan was going through a huge economic growth, and supermarkets selling a wide range of commodities from foodstuff to clothing began to spring up in many neighbourhoods. Cash registers that were then used at checkout counters in these stores required the price to be keyed in manually. Because of this, many cashiers suffered from numbness in the wrist and carpal tunnel syndrome.

The invention of the ‘Bar codes’ made the process easier as the price of an item or merchandise was displayed on the cash register automatically when the barcode on the item was scanned by an optical sensor, and information on the item was sent to a computer at the same time.  This first barcode had a capacity to store 20 characters. Now the storage capacity has gone up to more than 7000 characters.

 

 

Working of QR codes:

A QR code consists of black squares arranged in a square grid on a white background, which can be read by an imaging device such as a camera. The patterns created represent  binary codes that can be interpreted to reveal the code's data. The benefit of using a QR code over a barcode is that the data can be extracted by scanning in both vertical and horizontal directions. Three larges squares are present at three corners of the pattern square which enable the QR scanner software to identify the ideal direction through which it must extract the data.

When the code is scanned using the QR scanner software or application, the software divides the image of the code into grids and then extracts the value of each small square depending on its colour viz. white or black. The software identifies the difference in colour viz. white and black and converts the colour input into bits. These bits are then decrypted based on their positioning into a useful output.

The total amount of data stored can reach up to 7089 numeric characters or 4296 alphanumeric(consisting of both alphabets & numbers) characters.

                                   Image credit: ResearchGate

How is it possible to obtain information even from a damaged QR code?

With varying amount of data stored in them, we can obtain  as much as 30 % of data from a damaged QR code!  Lesser is the storage capacity, higher is the error correction level.

QR codes use Reed-Solomon error correction to retrieve the corrupted data.  Generally, a QR code is subdivided into several ‘blocks’ which contain certain part of the message. Each block contains certain number of black and white squares that represent the information. The block size is chosen so that no attempt is made at correcting more than 15 errors per block; this limits the complexity of the decoding algorithm.

Following are few levels of error correction:

Level L (Low)	7% of data bytes can be restored.
Level M (Medium)	15% of data bytes can be restored.
Level Q (Quartile)	25% of data bytes can be restored.
Level H (High)	30% of data bytes can be restored.

After decoding, the blocks are combined together again. This method of dividing a code into blocks also helps to make decorative codes that have intentional errors that make them more attractive.

Example of an attractive QR code:

                                                  Image credit: QR code chimp

Applications of QR code:

 

1.   It was originally used to keep a track of various parts in the vehicle manufacturing industry. It made the tracking much easier and sophisticated.

 

2.The code is used to store hyperlinks to various webpages and can be observed in magazines and newspapers. The user can scan the code to reach the website.

                                                 

        

 

 

 

                                                                              Image credits: QR code generator                                                                                                                                                          

    A QR code used in road side advertisement banners       

3.With a widened internet bandwidth, several users prefer to use internet banking for day to day payments. A large number of vendors use QR codes to store the payment gateway information. So the consumer can scan the code and pay the desired amount.

Credits & References:

Written by:- Sanket Gore(Team Tech Tuesday )

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