Barcode A barcode is an optical machine-readable representation of data relating to the object to which it is attached. Originally barcodes systematically represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or one-dimensional (1D). Later they evolved into rectangles, dots, hexagons and other geometric patterns in two dimensions (2D). Although 2D systems use a variety of symbols, they are generally referred to as barcodes as well. Barcodes originally were scanned by special optical scanners called barcode readers. Later, scanners and interpretive software became available on devices including desktop printers and smartphones. 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 representing things 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 in the field. Barcodes became commercially successful when they were used to automate supermarket checkout systems, a task for which they have become almost universal. Their use has spread to many other tasks that are generically referred to as automatic identification and data capture (AIDC). The very first scanning of the now ubiquitous Universal Product Code (UPC) barcode was on a pack of Wrigley Company chewing gum in June 1974. Other systems have made inroads in the AIDC market, but the simplicity, universality and low cost of barcodes has limited the role of these other systems until the 2000s (decade), over 40 years after the introduction of the commercial barcode, with the introduction of technologies such as radio frequency identification, or RFID. In 1948 Bernard Silver, a graduate student at Drexel Institute of Technology in Philadelphia, Pennsylvania, US overheard the president of the local food chain, Food Fair, asking one of the deans to research a system to automatically read product information during checkout. Silver told his friend Norman Joseph Woodland about the request, and they started working on a variety of systems. Their first working system used ultraviolet ink, but the ink faded too easily and was rather expensive. Convinced that the system was workable with further development, Woodland left Drexel, moved into his fathers apartment in Florida, and continued working on the system. His next inspiration came from Morse code, and he formed his first barcode from sand on the beach. I just extended the dots and dashes downwards and made narrow lines and wide lines out of them. To read them, he adapted technology from optical soundtracks in movies, using a 500-watt incandescent light bulb shining through the paper onto an RCA935 photomultiplier tube (from a movie projector) on the far side. He later decided that the system would work better if it were printed as a circle instead of a line, allowing it to be scanned in any direction. On 20 October 1949 Woodland and Silver filed a patent application for Classifying Apparatus and Method, in which they described both the linear and bullseye printing patterns, as well as the mechanical and electronic systems needed to read the code. The patent was issued on 7 October 1952 as US Patent 2,612,994. In 1951, Woodland moved to IBM and continually tried to interest IBM in developing the system. The company eventually commissioned a report on the idea, which concluded that it was both feasible and interesting, but that processing the resulting information would require equipment that was some time off in the future. IBM offered to buy the patent, but its offer was not high enough. Philco purchased their patent in 1962 and then sold it to RCA sometime later. Barcodes such as the UPC have become a ubiquitous element of modern civilization, as evidenced by their enthusiastic adoption by stores around the world; most items other than fresh produce from a grocery store now have UPC barcodes.[citation needed] This helps track items and also reduces instances of shoplifting involving price tag swapping, although shoplifters can now print their own barcodes.[14] In addition, retail chain membership cards (issued mostly by grocery stores and specialty big box retail stores such as sporting equipment, office supply, or pet stores) use barcodes to uniquely identify consumers, 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 can allow for the organization of large amounts of data. They are widely used in the healthcare and hospital settings, ranging from patient identification (to access patient data, including medical history, drug allergies, etc.) to creating SOAP Notes[15] with barcodes to medication management. They are also used to facilitate the separation and indexing of documents that have been imaged in batch scanning applications, track the organization of species in biology,[16] and integrate with in-motion checkweighers to identify the item being weighed in a conveyor line for data collection. They can also be used to keep track of objects and people; they are used to keep track of rental cars, airline luggage, nuclear waste, registered mail, express mail and parcels. Barcoded tickets allow the holder to enter sports arenas, cinemas, theatres, fairgrounds, and transportation, and are used to record the arrival and departure of vehicles from rental facilities etc. This can allow proprietors to identify duplicate or fraudulent tickets more easily. Barcodes are widely used in shop floor control applications software where employees can scan work orders and track the time spent on a job. Barcodes are also used in some kinds of non-contact 1D and 2D position sensors. A series of barcodes are used in some kinds of absolute 1D linear encoder. The barcodes are packed close enough together that the reader always has one or two barcodes in its field of view. The relative position of the barcode in the field of view of the reader gives incremental precise positioning, in some cases with sub-pixel resolution. The data decoded from the barcode gives the absolute coarse position. An address carpet, such as Howells binary pattern and the Anoto dot pattern, is a 2D barcode designed so that a reader, even though only a tiny portion of the complete carpet is in the field of view of the reader, can find its absolute X,Y position and rotation in the carpet.[17][18] Some 2D barcodes embed a hyperlink to a web page. A capable cellphone might be used to read the pattern and browse the linked website, which can help a shopper find the best price for an item in the vicinity. Since 2005, airlines use an IATA-standard 2D barcode on boarding passes (Bar Coded Boarding Pass (BCBP)), and since 2008 2D barcodes sent to mobile phones enable electronic boarding passes.[19] Some applications for barcodes have fallen out of use; In the 1970s and 1980s, software source code was occasionally encoded in a barcode and printed on paper (Cauzin Softstrip and Paperbyte[20] are barcode symbologies specifically designed for this application), and the 1991 Barcode Battler computer game system used any standard barcode to generate combat statistics. In the 21st century, many artists have started using barcodes in art, such as Scott Blakes Barcode Jesus, as part of the post-modernism movement. The earliest, and still the cheapest, barcode scanners are built from a fixed light and a single photosensor that is manually scrubbed across the barcode. Barcode scanners can be classified into three categories based on their connection to the computer. The older type is the RS-232 barcode scanner. This type requires special programming for transferring the input data to the application program. Keyboard interface scanners connect to a computer using a PS/2 or AT keyboard–compatible adaptor cable (a keyboard wedge). The barcodes data is sent to the computer as if it had been typed on the keyboard. Like the keyboard interface scanner, USB scanners are easy to install and do not need custom code for transferring input data to the application program. On PCs running Windows the HID interface emulates the data merging action of a hardware keyboard wedge, and the scanner automatically behaves like an additional keyboard. Many phones are able to decode barcodes using their built-in camera, as well. Googles mobile Android operating system uses both their own Google Goggles application or third party barcode scanners like Scan.[21] Nokias Symbian operating system features a barcode scanner,[22] while mbarcode[23] is a QR code reader for the Maemo operating system. In the Apple iOS, a barcode reader is not natively included but more than fifty paid and free apps are available with both scanning capabilities and hard-linking to URI. With BlackBerry devices, the App World application can natively scan barcodes and load any recognized Web URLs on the devices Web browser. Windows Phone 7.5 is able to scan barcodes through the Bing search app. However, these devices are not designed specifically for the capturing of barcodes. As a result, they do not decode nearly as quickly or accurately as a dedicated barcode scanner or portable data terminal. Barcode verification examines scanability and the quality of the barcode in comparison to industry standards and specifications. Barcode verifiers are primarily used by businesses that print and use barcodes. Any trading partner in the supply chain can test barcode quality. It is important to verify a barcode to ensure that any reader in the supply chain can successfully interpret a barcode with a low error rate. Retailers levy large penalties for non-compliant barcodes. These chargebacks can reduce a manufacturers revenue by 2% to 10%.[24] A barcode verifier works the way a reader does, but instead of simply decoding a barcode, a verifier performs a series of tests. For linear barcodes these tests are: Edge Determination Minimum Reflectance Symbol Contrast Minimum Edge Contrast Modulation Defects Decode Decodability 2D matrix symbols look at the parameters: Symbol Contrast Modulation Decode Unused Error Correction Fixed (finder) Pattern Damage Grid Non-uniformity Axial Non-uniformity[25] Depending on the parameter, each ANSI test is graded from 0.0 to 4.0 (F to A), or given a pass or fail mark. Each grade is determined by analyzing the scan reflectance profile (SRP), an analog graph of a single scan line across the entire symbol. The lowest of the 8 grades is the scan grade and the overall ISO symbol grade is the average of the individual scan grades. For most applications a 2.5 (C) is the minimum acceptable symbol grade.[26] Compared with a reader, a verifier measures a barcodes optical characteristics to international and industry standards. The measurement must be repeatable and consistent. Doing so requires constant conditions such as distance, illumination angle, sensor angle and verifier aperture. Based on the verification results, the production process can be adjusted to print higher quality barcodes that will scan down the supply chain. Barcode verifier standards Barcode verifiers should comply with the ISO/IEC 15416 (linear)] or ISO/IEC 15426-2 (2D). This standard defines the measuring accuracy of a barcode verifier. The current international barcode quality specification is ISO/IEC 15416 (linear) and ISO/IEC 15415 (2D). The European Standard EN 1635 has been withdrawn and replaced by ISO/IEC 15416. The original U.S. barcode quality specification was ANSI X3.182. (UPCs used in the US – ANSI/UCC5). This standard defines the quality requirements for barcodes and Matrix Codes (also called Optical Codes). As of 2011 the ISO workgroup JTC1 SC31 was developing a Direct Part Marking (DPM) quality standard : ISO/IEC TR 29158.[27] International standards are available from the International Organization for Standardization (ISO).[28] These standards are also available from local/national standardization organizations, such as ANSI, BSI, DIN, NEN and others.
Posted on: Sun, 31 Aug 2014 04:45:40 +0000