Article - Issue 50, March 2012

HOW DOES THAT WORK - From Bar to QR

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Using machines to capture data optically is a highly effective way of gathering information, especially if it is presented in a standard visual ‘language’. In 1948, two young engineers based in Philadelphia invented the simple ‘bar code’ as a way to record stock information for supermarkets.

To be commercially viable, the code needed a versatile reader and in 1973 an IBM team led by one of the original inventors, Norman Woodland, finally got the Universal Product Code accepted by US manufacturers, using laser scanning technology. Data was represented in the widths and spacings of the array of parallel lines. Within a decade, the barcode was in use worldwide, from supermarkets to healthcare.

In the 1990s, a new square Quick Response (QR) format was developed by Toyota subsidiary Denso Wave for tracking automobile parts in production plants. The square format stores data both horizontally and vertically, enabling a hundred-fold increase in data content. The pattern of black and white square areas in the corners of the code grid orientates the decoding software, while a white barrier ‘quiet zone’ around the grid distinguishes code from noise. Square QR codes can be scanned by digital cameras rather than lasers, opening up the technology to a wider range of applications.

The combination of camera and mobile phone has taken the QR format to the mass market. Smartphones with internet connectivity provide their users with access to website links stored as QR codes, simply by photographing the printed image, enabling almost any functionality that the web can provide.

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