Folha: 'QR code: what is it, where does it come from and where is it going?'

(Reproduction of Marcelo Viana's column in Folha de S. Paulo.) They are strange and, frankly, quite ugly: after all, they weren't made to be seen by humans. Even the name is strange: what does QR even mean? Still, they are rapidly becoming one of the most ubiquitous elements in our lives today, present in practically all areas of human activity. In the mid-1970s, the UPC (Universal Product Code) barcode model was consolidated and widely used by stores and supply chains to identify a growing number of products. The UPC has 12 digits: one is for error control and correction, leaving 11 for identifying the product in question. This means there are 100,000,000,000 (one hundred billion) possible barcodes. To date, just over one billion have been used; many more will remain for the coming years. But the UPC has a serious limitation: the amount of information that can be encoded with just 11 digits is quite limited. As markets became more sophisticated, the need arose to include detailed product information, not just its identification number. For example, since the "mad cow" disease crisis, which killed dozens of people at the beginning of this century, consumers have wanted to know the origin of beef: well, it's not possible to provide that information in a simple UPC. In the early 1990s, engineer Masahiro Hara, from the Japanese automotive parts company Denso, faced an embarrassing situation. Denso sold kits containing different types of parts, and Hara's team was forced to label the box with a bunch of barcodes, one for each type. It would be much better to have a single code containing the complete description of the contents. Read more: 'Brazil's best opportunity', says Francisco José. Olympic Girls end the year at IMPA Tech. IMPA opens two more selection processes. Hara set out to develop a type of two-dimensional barcode (UPC is one-dimensional). The crucial inspiration came while he was observing a Go board, the Japanese game that uses white and black pieces placed on a rectangular grid (matrix). Thus, in 1994, the QR code was born, formed by a matrix of white or black squares, each representing a binary digit (white=0, black=1). The name was given by Hara: QR stands for "quick response" and indicates the speed of reading the new code. Ease of reading too: while UPC requires a specific laser reader, QR can be read by any digital camera with suitable software. When Apple , Samsung, etc. included this software in our cell phones, the QR code became accessible to everyone. These properties, combined with its enormous encoding and information capacity, its ability to correct errors – some QR codes can be read even with 30% destroyed! – and Denso's decision not to charge for its use, guaranteed the resounding success of the new code. From banknotes and coins to graves, these codes are increasingly present in various sectors of activity. The day when each of our medical records will be contained in a QR code is also not far off. To read the full article, visit the newspaper's website. Also read: Pi Center selects postdoctoral fellow. Reprint of the book 'Linear Algebra' is on sale at IMPA.