Barcode Technology - Description and Evolution of Technology

Barcode Technology

Description and Evolution of Technology

Barcode technology is ubiquitous in modern civilization. The technology itself arose in research labs as a response to industry demand in the early fifties. By the eighties, barcodes had evolved from their predecessors and been implemented throughout the retail sectors of the globe. Today, traditional barcodes have been credited for saving Canadian companies over $17B per year . Nevertheless, barcodes are regarded as a mature technology with diminutive room for advancement. As society craves more storage capacity in identification tags, there is a shift in focus towards Radio Frequency Identification (RFID) tags which is poised to replace barcodes as the dominant design. Figure 1 shows the S-curves for barcode technology.

Barcodes were invented in 1948 by Bernard Silver, and Norman Woodland at the Drexel Institute of Technology. These two graduate students were awarded U.S. Patent 2612994 for this technology in 1952, where it was first used for identifying railroad cars. A barcode is essentially a binary code that uses black and white parallel lines to represent 1s and 0s. The "code" which is used to represent information in barcodes is called a symbology. Early symbologies such as "Code 39" could only encode numbers, but later the full ASCII set could be encoded. The most common decoder technology used for scanning barcodes is the laser scanner. Examples of these scanners are those manufactured by Symbol Technologies (acquired by Motorola in January 9th, 2007) which can be seen in many supermarkets.

Barcodes did not diffuse into industry until decades after its invention. It was first put into commercial use in 1966, when the National Association of Food Chains (NAFC) won the design competition and pushed for the use of this technology in supermarkets. The difficulty in implementing barcodes was due to the high cost of both the scanners for the retail outlets, and the labels for manufacturers. After many years of incremental improvements in symbologies and scanning/printing hardware, barcodes experienced its first revolution in 1974. The UPC standard (Universal Product Code) was introduced by the NAFC to grocery chains nationwide. It became the dominant design and remains the most common symbology used today. UPC is a flexible symbology which can hold more data, as well as support the ASCII set of characters. The US Military gave barcodes a further boost by adopting barcode technology in the early eighties using a revised version of "Code 39".

Due to advancements in symbologies and the accuracy of laser scanners, barcode usage boomed in the 1980s, and is now used to identify nearly all retail products, airline luggage, rental cars, and manufacturing work in progress. The benefits of barcodes stretch beyond product identification. The time and volume data provided by barcodes allow companies to track consumer behavior, inventory levels, improves traceability for products, and reduces theft. During the 1990s, as the information revolution took hold, the amount of data stored in traditional linear barcodes was no longer sufficient. To solve this problem the 2D barcode was introduced, which was essentially a grid of black and white squares. Scanner technology has also been improved incrementally, and now digital cameras can read barcodes more accurately and at different angles. Figure 3 displays the performance improvements that camera scanners have over laser scanners.

There are a few key physical limitations to barcode technology. The most important is that as more and more data needs to be encoded, the barcode itself has to grow larger, which is a significant problem for small objects. Also, barcodes need to be printed on a flat, reflective surface, and hence cannot be used for irregular shaped objects. The distance to which a barcode can be scanned is approximately 10cm, and there is only a small tolerance on the scanning angle. These limitations motivate the introduction of a new technology and a discontinuity - the RFID tag.

RFID tags send information via radio waves, and are scanned using radio scanners. Passive tags do not require an internal power source, and can store up to 128bits of information. In addition to offering more data than barcodes, RFID have a longer range of up to a few meters. Tags can be embedded in an object and does not need to be flatly placed on the surface. An entire pallet of products can be scanned without unpacking the individual boxes. Patented by Charles Walton in 1983 (U.S. Patent 4384288), RFID tags have a wide range of usage. Active tags which carry an internal power source, can record information over its 10 year battery life. For expensive durable goods, a record of information such as humidity, shock, light, and temperature can be very useful. Currently, RFID tags are used in passports, subway access cards, and livestock identification. This technology is still relatively expensive compared to barcodes, and the technology is in its infancy. However, as RFID travels up the S-curve , it should experience a boom in adoption and functional improvements. It is probable that RFID will be a competence destroying technology as it is a new product. All the manufacturers of bar code readers and data storage will not have the capabilities to offer RFID solutions and the advantage will be towards newcomers. Figure 4 shows the performance differences between barcode and RFID technology.

Standards

Many different barcodes standards have been developed. The types of standards which exist can be broken down along two dimensions; linear or two dimensional, and interleaved or non-interleaved. Linear barcodes are the simplest. They consist of a single horizontal series of black and white lines which are used to store information. Two dimensional bar codes are barcodes in which the black and white lines are spaced out not only on the horizontal axis, but the vertical axis as well. The simplest example of two dimensional barcodes is a series of linear barcodes stacked on top of one another. Interleaved barcodes use not only the black lines to store information, but the white lines which separate them as well. As the complexity of these standards increase, so do the accuracy, and the amount of information which can be stored in a given space. The tradeoff for this increased storage capacity, is the need for more complex scanning equipment and decoders. Two-dimensional barcodes for example generally cannot be read by laser scanners, and must be scanned by camera capture devices. See Figure 5 for a summary of common linear barcode standards (note the varying area required to store a given