Bar Codes Everywhere You Look

BAR CODE BASICS Labeling our world requires, well, labels. Today, this typically amounts to what’s commonly called a bar code. This term is synonymous with the Universal Product Code (UPC) and European Article Number (EAN) codes found on nearly every manufactured good and familiar to most consumers through their nearly ubiquitous use at grocery store checkouts. Depending on the exact type (www.adams1.com/ upccode.html), UPCs and EANs can encode several digits. These codes are fixed in length and limited to encoding numbers. UPC and EAN codes are but one type of 1D bar code. Other 1D bar codes, including the high-density Code 128, can encode alphanumeric characters, including all 128 ASCII characters. Use of Code 128 is common in the shipping industry. There are also 2D—or matrix—bar codes. (We’re not sure why these are still called bar codes because squares have replaced the bars.) Examples include QR (Quick Response), Data Matrix, and Aztec codes. Their main advantage is that they can represent a large amount of data in a fixed amount of space. QR codes (www.denso-wave.com/ qrcode/qrfeature-e.html) can encode any data type, including alphanumeric, Kanji, and Hiragana symbols. Their data capacity varies by data type, with numeric data having the most capacity (more than 7,000 digits) and Kanji the least (approximately 1,800 symbols). Similar to other 2D bar codes, QR codes encode information both horizontally and vertically. So, the image is more compact than a 1D bar code, requiring approximately 10 percent of the space necessary for an equivalent 1D bar code. QR codes became an ISO international standard (ISO/IEC 18004) nearly a decade ago. They’re in widespread use in Asia, particularly in Japan, where they often appear on billboards (see Figure 1), at bus stops, on LCD advertising, and even on food wrappers. They’re also common in Europe, although not as routinely visible. If people in these countries snap a photo of the QR code using their mobile phone’s camera, the phone’s software can decode the image and direct a Web browser to a URL stored in the QR code. The resulting Web page might contain information such as nutrition facts or event dates and times, or it might play a music video or let the user purchase tickets. Other uses include encoding a text message, a phone number, or a business card. Some proponents argue that the code should contain only an identifier, which is then looked up at a resolution service, but we like the independence enabled by decoding the image locally. QR codes are now spreading to the US. Google recently launched Favorite Places (www.google.com/help/maps/ favoriteplaces/gallery), wherein businesses post a sticker (see Figure 2) in their window identifying the store Bar Codes Everywhere You Look