A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths and spacings of parallel lines. These barcodes, now commonly referred to as linear or one-dimensional (1D), can be scanned by special optical scanners, called barcode readers. Later, two-dimensional (2D) variants were developed, using rectangles, dots, hexagons and other geometric patterns, called matrix codes or 2D barcodes, although they do not use bars as such. 2D barcodes can be read or deconstructed using application software on mobile devices with inbuilt cameras, such as smartphones.
Barcodes are widely used around the world in many contexts. In stores, UPC barcodes are pre-printed on most items. This speeds up processing at check-outs and helps track items. In addition, retail chain membership cards use barcodes to identify customers, allowing for customized marketing and greater understanding of individual consumer shopping patterns. At the point of sale, shoppers can get product discounts or special marketing offers through the address or e-mail address provided at registration. Barcodes are widely used in shop floor control applications software where employees can scan work orders and track the time spent on a job.
In point-of-sale management, barcode systems can provide detailed up-to-date information on the business, accelerating decisions and with more confidence. For example:
The barcode was invented by Norman Joseph Woodland and Bernard Silver and patented in the US in 1951. The invention was based on Morse code that was extended to thin and thick bars. However, it took over twenty years before this invention became commercially successful. An early use of one type of barcode in an industrial context was sponsored by the Association of American Railroads in the late 1960s.
Developed by General Telephone and Electronics (GTE) and called KarTrak ACI (Automatic Car Identification), this scheme involved placing colored stripes in various combinations on steel plates which were affixed to the sides of railroad rolling stock. Two plates were used per car, one on each side, with the arrangement of the colored stripes encoding information such as ownership, type of equipment, and identification number. The plates were read by a trackside scanner, located for instance, at the entrance to a classification yard, while the car was moving past. The project was abandoned after about ten years because the system proved unreliable after long-term use.
Barcodes became commercially successful when they were used to automate supermarket checkout systems, a task for which they have become almost universal. The Uniform Grocery Product Code Council had chosen, in 1973, the barcode design developed by George Laurer. Laurer's barcode, with vertical bars, printed better than the circular barcode developed by Woodland and Silver.
Their use has spread to many other tasks that are generically referred to as automatic identification and data capture (AIDC). The first scanning of the now-ubiquitous Universal Product Code (UPC) barcode was on a pack of Wrigley Company chewing gum in June 1974 at a Marsh supermarket in Troy, Ohio, using scanner produced by Photographic Sciences Corporation. QR codes, a specific type of 2D barcode, have recently become very popular.