QR code

A QR code is a special kind of square pattern used to store information. The name stands for "quick-response" code because it is designed to be read very fast.

Unlike a standard barcode that only shows a single line of data, a QR code is two-dimensional. This means it uses a grid of black and white squares to hold much more information. It can act as a locator, an identifier, or even a way to track web data. Because they hold so much, they are used for many different jobs today.

How does a camera actually read these patterns? First, the device looks for the large squares at the corners, called fiducial markers. These markers help the camera understand the code's position and shape.

Next, the device looks at the patterns in both the horizontal and vertical parts of the grid. It uses a special math method called Reed–Solomon error correction to process the image. This math is very helpful because it allows the code to be read even if it is a bit dirty or damaged.

Finally, the device extracts the data and turns it into something useful, like a website link.

The story of the QR code began in 1994 in Japan. A researcher named Masahiro Hara led a team at a company called Denso Wave. They wanted a better way to label automobile parts.

Before this, workers had to scan many small barcodes on different boxes. Hara's team created a single label that could hold all that data at once. They even got the idea for the pattern from the black and white pieces on a Go board. This invention made tracking car parts much faster and easier than before.

Since its invention, QR codes have spread all over the world. In June 2011, 14 million people in the United States scanned them. By 2022, that number grew to 89 million people scanning codes with mobile devices.

People use them for many things, like seeing a menu at a restaurant or making a payment. They are even found on paper money in places like Nigeria, Russia, and Ghana. Some people even use them to join a Wi-Fi network without typing a long password. They have become a common tool for both businesses and everyday people.

You probably see QR codes every day without even realizing it. They might be printed on a soda can to take you to a website.

They can be painted on large buildings or even placed on train tickets. You can use them to add a new contact to your phone or to send an email. Some companies even use them to create "virtual stores" where you scan an item to have it delivered to your home. They are a simple way to link the physical objects around you to the digital world.