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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, spacings and sizes 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, of which there are several types. Later, two-dimensional (2D) variants were developed, using rectangles, dots,
hexagon In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...
s and other patterns, called ''matrix codes'' or ''2D barcodes'', although they do not use bars as such. 2D barcodes can be read using purpose-built 2D optical scanners, which exist in a few different forms. 2D barcodes can also be read by a digital camera connected to a microcomputer running software that takes a photographic image of the barcode and analyzes the image to deconstruct and decode the 2D barcode. A
mobile device A mobile device (or handheld computer) is a computer small enough to hold and operate in the hand. Mobile devices typically have a flat LCD or OLED screen, a touchscreen interface, and digital or physical buttons. They may also have a physica ...
with an inbuilt camera, such as
smartphone A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whi ...
, can function as the latter type of 2D barcode reader using specialized
application software Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a ...
(The same sort of mobile device could also read 1D barcodes, depending on the application software). The barcode was invented by Norman Joseph Woodland and
Bernard Silver Bernard Silver (September 21, 1924 – August 28, 1963) was an early developer of barcode technology alongside Norman Joseph Woodland. Silver earned his Bachelor of Science in Electrical Engineering from the Drexel Institute of Technology in 1947. ...
and patented in the US in 1952. The invention was based on
Morse code Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one ...
that was extended to thin and thick bars. However, it took over twenty years before this invention became commercially successful. UK magazine '' Modern Railways'' December 1962 pages 387–389 record how
British Railways British Railways (BR), which from 1965 traded as British Rail, was a state-owned company that operated most of the overground rail transport in Great Britain from 1948 to 1997. It was formed from the nationalisation of the Big Four British ...
had already perfected a barcode-reading system capable of correctly reading rolling stock travelling at with no mistakes. 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 Corporation, formerly General Telephone & Electronics Corporation (1955–1982), was the largest independent telephone company in the United States during the days of the Bell System. The company operated from 1926, with roots tracing furth ...
(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 Checkout may refer to: * a point of sale terminal * Google Checkout, Google's online payment services * Check-Out (The Price Is Right), a segment game from ''The Price Is Right'' * in information management, it means blocking a file for editing; s ...
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's chewing gum in June 1974 at a Marsh supermarket in Troy, Ohio, using a scanner made by Photographic Sciences Corporation.
QR code A QR code (an initialism for quick response code) is a type of matrix barcode (or two-dimensional barcode) invented in 1994 by the Japanese company Denso Wave. A barcode is a machine-readable optical label that can contain information about t ...
s, a specific type of 2D barcode, have recently become very popular due to the growth in smartphone ownership. 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, particularly before technologies such as
radio-frequency identification Radio-frequency identification (RFID) uses electromagnetic fields to automatically Automatic identification system, identify and Tracking system, track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver ...
(RFID) became available after 1995.


History

In 1948
Bernard Silver Bernard Silver (September 21, 1924 – August 28, 1963) was an early developer of barcode technology alongside Norman Joseph Woodland. Silver earned his Bachelor of Science in Electrical Engineering from the Drexel Institute of Technology in 1947. ...
, a graduate student at Drexel Institute of Technology in
Philadelphia Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Since ...
, 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 Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
ink, but the ink faded too easily and was expensive. Convinced that the system was workable with further development, Woodland left Drexel, moved into his father's apartment in Florida, and continued working on the system. His next inspiration came from
Morse code Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one ...
, 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 bull's eye 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 the offer was not accepted. Philco purchased the patent in 1962 and then sold it to RCA sometime later.


Collins at Sylvania

During his time as an undergraduate, David Jarrett Collins worked at the Pennsylvania Railroad and became aware of the need to automatically identify railroad cars. Immediately after receiving his master's degree from MIT in 1959, he started work at GTE Sylvania and began addressing the problem. He developed a system called ''KarTrak'' using blue and red reflective stripes attached to the side of the cars, encoding a six-digit company identifier and a four-digit car number. Light reflected off the colored stripes was read by photomultiplier vacuum tubes. The
Boston and Maine Railroad The Boston and Maine Railroad was a U.S. Class I railroad in northern New England. Originally chartered in 1835, it became part of what was the Pan Am Railways network in 1983 (most of which was purchased by CSX in 2022). At the end of 1970 ...
tested the KarTrak system on their gravel cars in 1961. The tests continued until 1967, when the Association of American Railroads (AAR) selected it as a standard,
Automatic Car Identification Automatic equipment identification (AEI) is an electronic recognition system in use with the North American railroad industry. Consisting of passive tags mounted on each side of rolling stock and active trackside readers, AEI uses RF technology t ...
, across the entire North American fleet. The installations began on 10 October 1967. However, the economic downturn and rash of bankruptcies in the industry in the early 1970s greatly slowed the rollout, and it was not until 1974 that 95% of the fleet was labeled. To add to its woes, the system was found to be easily fooled by dirt in certain applications, which greatly affected accuracy. The AAR abandoned the system in the late 1970s, and it was not until the mid-1980s that they introduced a similar system, this time based on radio tags. The railway project had failed, but a toll bridge in
New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delawa ...
requested a similar system so that it could quickly scan for cars that had purchased a monthly pass. Then the U.S. Post Office requested a system to track trucks entering and leaving their facilities. These applications required special
retroreflector A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects radiation (usually light) back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirro ...
labels. Finally, Kal Kan asked the Sylvania team for a simpler (and cheaper) version which they could put on cases of pet food for inventory control.


Computer Identics Corporation

In 1967, with the
railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a p ...
system maturing, Collins went to management looking for funding for a project to develop a black-and-white version of the code for other industries. They declined, saying that the railway project was large enough, and they saw no need to branch out so quickly. Collins then quit Sylvania and formed the Computer Identics Corporation. As its first innovations, Computer Identics moved from using incandescent light bulbs in its systems, replacing them with helium–neon lasers, and incorporated a mirror as well, making it capable of locating a barcode up to several feet in front of the scanner. This made the entire process much simpler and more reliable, and typically enabled these devices to deal with damaged labels, as well, by recognizing and reading the intact portions. Computer Identics Corporation installed one of its first two scanning systems in the spring of 1969 at a
General Motors The General Motors Company (GM) is an American Multinational corporation, multinational Automotive industry, automotive manufacturing company headquartered in Detroit, Michigan, United States. It is the largest automaker in the United States and ...
(Buick) factory in Flint, Michigan. The system was used to identify a dozen types of transmissions moving on an overhead conveyor from production to shipping. The other scanning system was installed at General Trading Company's distribution center in Carlstadt, New Jersey to direct shipments to the proper loading bay.


Universal Product Code

In 1966, the National Association of Food Chains (NAFC) held a meeting on the idea of automated checkout systems. RCA, who had purchased the rights to the original Woodland patent, attended the meeting and initiated an internal project to develop a system based on the bullseye code. The Kroger grocery chain volunteered to test it. In the mid-1970s, the NAFC established the Ad-Hoc Committee for U.S. Supermarkets on a Uniform Grocery-Product Code to set guidelines for barcode development. In addition, it created a symbol-selection subcommittee to help standardize the approach. In cooperation with consulting firm, McKinsey & Co., they developed a standardized 11-digit code for identifying products. The committee then sent out a contract tender to develop a barcode system to print and read the code. The request went to Singer,
National Cash Register NCR Corporation, previously known as National Cash Register, is an American software, consulting and technology company providing several professional services and electronic products. It manufactures self-service kiosks, point-of-sale termin ...
(NCR), Litton Industries, RCA,
Pitney-Bowes Pitney Bowes Inc. is an American technology company most known for its postage meters and other mailing equipment and services, and with expansions into e-commerce, software, and other technologies. The company was founded by Arthur Pitney, who ...
, IBM and many others. A wide variety of barcode approaches was studied, including linear codes, RCA's bullseye concentric circle code,
starburst MicroPro International Corporation was an American software company founded in 1978 in San Rafael, California. They are best known as the publisher of WordStar, a popular early word processor for personal computers. History Founding and early su ...
patterns and others. In the spring of 1971, RCA demonstrated their bullseye code at another industry meeting. IBM executives at the meeting noticed the crowds at the RCA booth and immediately developed their own system. IBM marketing specialist Alec Jablonover remembered that the company still employed Woodland, and he established a new facility in Raleigh-Durham Research Triangle Park to lead development. In July 1972, RCA began an 18-month test in a Kroger store in Cincinnati. Barcodes were printed on small pieces of adhesive paper, and attached by hand by store employees when they were adding price tags. The code proved to have a serious problem; the printers would sometimes smear ink, rendering the code unreadable in most orientations. However, a linear code, like the one being developed by Woodland at IBM, was printed in the direction of the stripes, so extra ink would simply make the code "taller" while remaining readable. So on 3 April 1973, the IBM UPC was selected as the NAFC standard. IBM had designed five versions of UPC symbology for future industry requirements: UPC A, B, C, D, and E. NCR installed a testbed system at Marsh's Supermarket in Troy, Ohio, near the factory that was producing the equipment. On 26 June 1974, Clyde Dawson pulled a 10-pack of Wrigley's Juicy Fruit gum out of his basket and it was scanned by Sharon Buchanan at 8:01 am. The pack of gum and the receipt are now on display in the
Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Found ...
. It was the first commercial appearance of the UPC. In 1971, an IBM team was assembled for an intensive planning session, threshing out, 12 to 18 hours a day, how the technology would be deployed and operate cohesively across the system, and scheduling a roll-out plan. By 1973, the team were meeting with grocery manufacturers to introduce the symbol that would need to be printed on the packaging or labels of all of their products. There were no cost savings for a grocery to use it, unless at least 70% of the grocery's products had the barcode printed on the product by the manufacturer. IBM projected that 75% would be needed in 1975. Yet, although this was achieved, there were still scanning machines in fewer than 200 grocery stores by 1977. Economic studies conducted for the grocery industry committee projected over $40 million in savings to the industry from scanning by the mid-1970s. Those numbers were not achieved in that time-frame and some predicted the demise of barcode scanning. The usefulness of the barcode required the adoption of expensive scanners by a critical mass of retailers while manufacturers simultaneously adopted barcode labels. Neither wanted to move first and results were not promising for the first couple of years, with ''Business Week'' proclaiming "The Supermarket Scanner That Failed" in a 1976 article. On the other hand, experience with barcode scanning in those stores revealed additional benefits. The detailed sales information acquired by the new systems allowed greater responsiveness to customer habits, needs and preferences. This was reflected in the fact that about 5 weeks after installing barcode scanners, sales in grocery stores typically started climbing and eventually leveled off at a 10–12% increase in sales that never dropped off. There was also a 1–2% decrease in operating cost for those stores, and this enabled them to lower prices and thereby to increase market share. It was shown in the field that the
return on investment Return on investment (ROI) or return on costs (ROC) is a ratio between net income (over a period) and investment (costs resulting from an investment of some resources at a point in time). A high ROI means the investment's gains compare favourably ...
for a barcode scanner was 41.5%. By 1980, 8,000 stores per year were converting. Sims Supermarkets were the first location in Australia to use barcodes, starting in 1979.


Industrial adoption

In 1981, the
United States Department of Defense The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national sec ...
adopted the use of
Code 39 Code 39 (also known as Alpha39, Code 3 of 9, Code 3/9, Type 39, USS Code 39, or USD-3) is a variable length, discrete barcode symbology. The Code 39 specification defines 43 characters, consisting of uppercase letters (A through Z), numeric digi ...
for marking all products sold to the United States military. This system, Logistics Applications of Automated Marking and Reading Symbols (LOGMARS), is still used by DoD and is widely viewed as the catalyst for widespread adoption of barcoding in industrial uses.


Use

Barcodes are widely used around the world in many contexts. In stores, UPC barcodes are pre-printed on most items other than fresh produce from a
grocery store A grocery store ( AE), grocery shop ( BE) or simply grocery is a store that primarily retails a general range of food products, which may be fresh or packaged. In everyday U.S. usage, however, "grocery store" is a synonym for supermarket, a ...
. This speeds up processing at check-outs and helps track items and also reduces instances of
shoplifting Shoplifting is the theft of goods from an open retail establishment, typically by concealing a store item on one's person, in pockets, under clothes or in a bag, and leaving the store without paying. With clothing, shoplifters may put on item ...
involving price tag swapping, although shoplifters can now print their own barcodes. Barcodes that encode a book's
ISBN The International Standard Book Number (ISBN) is a numeric commercial book identifier that is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency. An ISBN is assigned to each separate edition a ...
are also widely pre-printed on books, journals and other printed materials. 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 the healthcare and hospital settings, ranging from patient identification (to access patient data, including medical history, drug allergies, etc.) to creating SOAP Notes 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, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
in biology, and integrate with in-motion
checkweigher A checkweigher is an automatic or manual machine for checking the weight of packaged commodities. It is normally found at the offgoing end of a production process and is used to ensure that the weight of a pack of the commodity is within specif ...
s 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 car Renting, also known as hiring or letting, is an agreement where a payment is made for the temporary use of a good, service or property owned by another. A gross lease is when the tenant pays a flat rental amount and the landlord pays for ...
s, airline luggage, nuclear waste, registered mail,
express mail Express mail is an expedited mail delivery service for which the customer pays a premium for faster delivery. Express mail is a service for domestic and international mail, and is in most nations governed by the country's own postal administratio ...
and parcels. Barcoded tickets (which may be printed by the customer on their home printer, or stored on their mobile device) 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 sensor A position sensor is a sensor that detects an object's position. A position sensor may indicate the absolute position of the object (its location) or its relative position (displacement) in terms of linear travel, rotational angle or three-dimension ...
s. 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. As a kind of
fiducial marker A fiducial marker or fiducial is an object placed in the field of view of an imaging system that appears in the image produced, for use as a point of reference or a measure. It may be either something placed into or on the imaging subject, or a ...
, 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 Howell's 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. 2D barcodes can embed a
hyperlink In computing, a hyperlink, or simply a link, is a digital reference to data that the user can follow or be guided by clicking or tapping. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text w ...
to a web page. A mobile device with an inbuilt camera 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. 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 Cauzin Softstrip was the first commercial 2D barcode format. Introduced in 1985, it could store up to 1000 bytes per square inch, which was 20 to 100 times more than the bar codes of the day. It was designed to allow magazines to distribute compu ...
and Paperbyte are barcode symbologies specifically designed for this application), and the 1991 ''
Barcode Battler The is a handheld game console released by Epoch Co. in March 1991. The console at retail was supplied with a number of cards, each of which had a barcode. Upon starting the game, the player must swipe a barcode representing a player. The game ...
'' computer game system used any standard barcode to generate combat statistics. Artists have used barcodes in art, such as Scott Blake's Barcode Jesus, as part of the
post-modernism Postmodernism is an intellectual stance or mode of discourseNuyen, A.T., 1992. The Role of Rhetorical Devices in Postmodernist Discourse. Philosophy & Rhetoric, pp.183–194. characterized by skepticism toward the " grand narratives" of moder ...
movement.


Symbologies

The mapping between messages and barcodes is called a ''
symbology A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different co ...
''. The specification of a symbology includes the encoding of the message into bars and spaces, any required start and stop markers, the size of the quiet zone required to be before and after the barcode, and the computation of a checksum. Linear symbologies can be classified mainly by two properties: ; Continuous vs. discrete * Characters in discrete symbologies are composed of ''n'' bars and ''n'' − 1 spaces. There is an additional space between characters, but it does not convey information, and may have any width as long as it is not confused with the end of the code. * Characters in continuous symbologies are composed of ''n'' bars and ''n'' spaces, and usually abut, with one character ending with a space and the next beginning with a bar, or vice versa. A special end pattern that has bars on both ends is required to end the code. ;Two-width vs. many-width * A two-width, also called a binary bar code, contains bars and spaces of two widths, "wide" and "narrow". The precise width of the wide bars and spaces is not critical; typically, it is permitted to be anywhere between 2 and 3 times the width of the narrow equivalents. * Some other symbologies use bars of two different heights ( POSTNET), or the presence or absence of bars ( CPC Binary Barcode). These are normally also considered binary bar codes. * Bars and spaces in many-width symbologies are all multiples of a basic width called the ''module''; most such codes use four widths of 1, 2, 3 and 4 modules. Some symbologies use interleaving. The first character is encoded using black bars of varying width. The second character is then encoded by varying the width of the white spaces between these bars. Thus, characters are encoded in pairs over the same section of the barcode.
Interleaved 2 of 5 Interleaved 2 of 5 (ITF) is a continuous two-width barcode symbology encoding digits. It is used commercially on 135 film, for ITF-14 barcodes, and on cartons of some products, while the products inside are labeled with UPC or EAN. ITF enco ...
is an example of this. Stacked symbologies repeat a given linear symbology vertically. The most common among the many 2D symbologies are matrix codes, which feature square or dot-shaped modules arranged on a grid pattern. 2D symbologies also come in circular and other patterns and may employ steganography, hiding modules within an image (for example, DataGlyphs). Linear symbologies are optimized for laser scanners, which sweep a light beam across the barcode in a straight line, reading a ''slice'' of the barcode light-dark patterns. Scanning at an angle makes the modules appear wider, but does not change the width ratios. Stacked symbologies are also optimized for laser scanning, with the laser making multiple passes across the barcode. In the 1990s development of charge-coupled device (CCD) imagers to read barcodes was pioneered by
Welch Allyn Welch Allyn, Inc. is an American manufacturer of medical devices and patient monitoring systems. Headquartered in Skaneateles Falls, New York, it was family-owned until it was acquired in 2015 by Hillrom. Hillrom was purchased by Baxter Interna ...
. Imaging does not require moving parts, as a laser scanner does. In 2007, linear imaging had begun to supplant laser scanning as the preferred scan engine for its performance and durability. 2D symbologies cannot be read by a laser, as there is typically no sweep pattern that can encompass the entire symbol. They must be scanned by an image-based scanner employing a CCD or other digital camera sensor technology.


Barcode readers

The earliest, and still the cheapest, barcode scanners are built from a fixed light and a single photosensor that is manually moved 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 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' ('' data terminal equipment'') suc ...
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 The Personal System/2 or PS/2 is IBM's second generation of personal computers. Released in 1987, it officially replaced the IBM PC, XT, AT, and PC Convertible in IBM's lineup. Many of the PS/2's innovations, such as the 16550 UART (serial p ...
or
AT keyboard The Model F was a series of computer keyboards produced mainly from 1981–1985 and in reduced volume until 1994 by IBM and later Lexmark. Its mechanical-key design consisted of a buckling spring over a capacitive PCB, similar to the later Mod ...
–compatible adaptor cable (a " keyboard wedge"). The barcode's data is sent to the computer as if it had been typed on the keyboard. Like the keyboard interface scanner, USB scanners do not need custom code for transferring input data to the application program. On PCs running Windows the human interface device emulates the data merging action of a hardware "keyboard wedge", and the scanner automatically behaves like an additional keyboard. Most modern smartphones are able to decode barcode using their built-in camera. Google's mobile Android operating system can use their own Google Lens application to scan QR codes, or third-party apps like Barcode Scanner to read both one-dimensional barcodes and QR codes. Nokia's
Symbian Symbian is a discontinued mobile operating system (OS) and computing platform designed for smartphones. It was originally developed as a proprietary software OS for personal digital assistants in 1998 by the Symbian Ltd. consortium. Symbian OS ...
operating system featured a barcode scanner, while mbarcode is a
QR code A QR code (an initialism for quick response code) is a type of matrix barcode (or two-dimensional barcode) invented in 1994 by the Japanese company Denso Wave. A barcode is a machine-readable optical label that can contain information about t ...
reader for the Maemo operating system. In Apple
iOS 11 iOS 11 is the iOS version history, eleventh major release of the iOS mobile operating system developed by Apple Inc., being the successor to iOS 10. It was announced at the company's Apple Worldwide Developers Conference, Worldwide Developers C ...
, the native camera app can decode QR codes and can link to URLs, join wireless networks, or perform other operations depending on the QR Code contents. Other paid and free apps are available with scanning capabilities for other symbologies or for earlier iOS versions. With
BlackBerry The blackberry is an edible fruit produced by many species in the genus ''Rubus'' in the family Rosaceae, hybrids among these species within the subgenus ''Rubus'', and hybrids between the subgenera ''Rubus'' and ''Idaeobatus''. The taxonomy ...
devices, the App World application can natively scan barcodes and load any recognized Web URLs on the device's 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 A portable data terminal, or shortly PDT, is an electronic device that is used to enter or retrieve data via wireless transmission (WLAN or WWAN). They have also been called enterprise digital assistants (EDA), data capture mobile devices, batch ...
.


Quality control and verification

It is common for producers and users of bar codes to have a
quality management system A quality management system (QMS) is a collection of business processes focused on consistently meeting customer requirements and enhancing their satisfaction. It is aligned with an organization's purpose and strategic direction (ISO 9001:2015). I ...
which includes verification and validation of bar codes. 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 In commerce, a supply chain is a network of facilities that procure raw materials, transform them into intermediate goods and then final products to customers through a distribution system. It refers to the network of organizations, people, activ ...
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 manufacturer's revenue by 2% to 10%. 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 contrast (EC) **The difference between the space reflectance (Rs) and adjoining bar reflectance (Rb). EC=Rs-Rb * Minimum bar reflectance (Rb) **The smallest reflectance value in a bar. * Minimum space reflectance (Rs) **The smallest reflectance value in a space. *Symbol contrast (SC) **Symbol Contrast is the difference in reflectance values of the lightest space (including the quiet zone) and the darkest bar of the symbol. The greater the difference, the higher the grade. The parameter is graded as either A, B, C, D, or F. SC=Rmax-Rmin * Minimum edge contrast (ECmin) **The difference between the space reflectance (Rs) and adjoining bar reflectance (Rb). EC=Rs-Rb * Modulation (MOD) **The parameter is graded either A, B, C, D, or F. This grade is based on the relationship between minimum edge contrast (ECmin) and symbol contrast (SC). MOD=ECmin/SC The greater the difference between minimum edge contrast and symbol contrast, the lower the grade. Scanners and verifiers perceive the narrower bars and spaces to have less intensity than wider bars and spaces; the comparison of the lesser intensity of narrow elements to the wide elements is called modulation. This condition is affected by aperture size. *Inter-character gap **In discrete barcodes, the space that disconnects the two contiguous characters. When present, inter-character gaps are considered spaces (elements) for purposes of edge determination and reflectance parameter grades. * Defects * Decode **Extracting the information which has been encoded in a bar code symbol. * Decodability **Can be graded as A, B, C, D, or F. The Decodability grade indicates the amount of error in the width of the most deviant element in the symbol. The less deviation in the symbology, the higher the grade. Decodability is a measure of print accuracy using the symbology reference decode algorithm. 2D matrix symbols look at the parameters: * Symbol contrast * Modulation * Decode * Unused error correction * Fixed (finder) pattern damage * Grid non-uniformity * Axial non-uniformity 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 minimal acceptable symbol grade. Compared with a reader, a verifier measures a barcode's 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 In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...
. Based on the verification results, the production process can be adjusted to print higher quality barcodes that will scan down the supply chain. Bar code validation may include evaluations after use (and abuse) testing such as sunlight, abrasion, impact, moisture, etc.


Barcode verifier standards

Barcode verifier standards are defined by the
International Organization for Standardization The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in A ...
(ISO), in ISO/IEC 15426-1 (linear) or ISO/IEC 15426-2 (2D). 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). As of 2011 the ISO workgroup JTC1 SC31 was developing a Direct Part Marking (DPM) quality standard: ISO/IEC TR 29158.


Benefits

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: * Fast-selling items can be identified quickly and automatically reordered. * Slow-selling items can be identified, preventing inventory build-up. * The effects of merchandising changes can be monitored, allowing fast-moving, more profitable items to occupy the best space. * Historical data can be used to predict seasonal fluctuations very accurately. * Items may be repriced on the shelf to reflect both sale prices and price increases. * This technology also enables the profiling of individual consumers, typically through a voluntary registration of discount cards. While pitched as a benefit to the consumer, this practice is considered to be potentially dangerous by privacy advocates. Besides sales and inventory tracking, barcodes are very useful in logistics and supply chain management. * When a manufacturer packs a box for shipment, a Unique Identifying Number (UID) can be assigned to the box. * A database can link the UID to relevant information about the box; such as order number, items packed, quantity packed, destination, etc. * The information can be transmitted through a communication system such as Electronic Data Interchange (EDI) so the retailer has the information about a shipment before it arrives. * Shipments that are sent to a Distribution Center (DC) are tracked before forwarding. When the shipment reaches its final destination, the UID gets scanned, so the store knows the shipment's source, contents, and cost. Barcode scanners are relatively low cost and extremely accurate compared to key-entry, with only about 1 substitution error in 15,000 to 36 trillion characters entered. The exact error rate depends on the type of barcode.


Types of barcodes


Linear barcodes

A first generation, "one dimensional" barcode that is made up of lines and spaces of various widths or sizes that create specific patterns.


Matrix (2D) barcodes

A ''matrix code'', also termed a ''2D barcode'' (although not using bars as such) or simply a ''2D code'', is a two-dimensional way to represent information. It is similar to a linear (1-dimensional) barcode, but can represent more data per unit area.


Example images

File:UPC-A-036000291452.png, GTIN-12 number encoded in UPC-A barcode symbol. First and last digit are always placed outside the symbol to indicate Quiet Zones that are necessary for barcode scanners to work properly File:EAN-13-5901234123457.svg, EAN-13 (GTIN-13) number encoded in EAN-13 barcode symbol. First digit is always placed outside the symbol, additionally right quiet zone indicator (>) is used to indicate Quiet Zones that are necessary for barcode scanners to work properly File:Code93.png, "Wikipedia" encoded in Code 93 File:Code39.png, "*WIKI39*" encoded in
Code 39 Code 39 (also known as Alpha39, Code 3 of 9, Code 3/9, Type 39, USS Code 39, or USD-3) is a variable length, discrete barcode symbology. The Code 39 specification defines 43 characters, consisting of uppercase letters (A through Z), numeric digi ...
File:Wikipedia barcode 128.svg, 'Wikipedia" encoded in Code 128 File:Codablock-F Example.png, An example of a ''stacked barcode''. Specifically a "Codablock" barcode. File:Better Sample PDF417.png, PDF417 sample File:Lorem Ipsum.png, Lorem ipsum
boilerplate text Boilerplate text, or simply boilerplate, is any written text ( copy) that can be reused in new contexts or applications without significant changes to the original. The term is used about statements, contracts, and computer code, and is used in th ...
as four segment Data Matrix 2D File:Azteccodeexample.svg, "This is an example Aztec symbol for Wikipedia" encoded in Aztec Code File:EZcode.png, Text 'EZcode' File:High Capacity Color Barcode.png, High Capacity Color Barcode of the URL for Wikipedia's article on
High Capacity Color Barcode High Capacity Color Barcode (HCCB) is a technology developed by Microsoft for encoding data in a 2D "barcode" using clusters of colored triangles instead of the square pixels conventionally associated with 2D barcodes or QR codes. Data density is ...
File:Dataglyph511140.png, "Wikipedia, The Free Encyclopedia" in several languages encoded in DataGlyphs File:35mm film audio macro.jpg, Two different 2D barcodes used in film:
Dolby Digital Dolby Digital, originally synonymous with Dolby AC-3, is the name for what has now become a family of audio compression technologies developed by Dolby Laboratories. Formerly named Dolby Stereo Digital until 1995, the audio compression is loss ...
between the sprocket holes with the "Double-D" logo in the middle, and
Sony Dynamic Digital Sound is a cinema sound system developed by Sony, in which compressed digital sound information is recorded on both outer edges of the 35 mm film release print. The system supports up to eight independent channels of sound: five front chann ...
in the blue area to the left of the sprocket holes File:WikiQRCode.png, The
QR Code A QR code (an initialism for quick response code) is a type of matrix barcode (or two-dimensional barcode) invented in 1994 by the Japanese company Denso Wave. A barcode is a machine-readable optical label that can contain information about t ...
for the Wikipedia URL. "Quick Response", the most popular 2D barcode. It is open in that the specification is disclosed and the patent is not exercised. File:MaxiCode.svg, MaxiCode example. This encodes the string "Wikipedia, The Free Encyclopedia" File:Shotcode.png, ShotCode sample File:Twibright Optar Detail Scanned.png, detail of Twibright Optar scan from laser printed paper, carrying 32 kbit/s Ogg Vorbis digital music (48 seconds per A4 page) File:KarTrak code.jpg, A
KarTrak KarTrak, sometimes KarTrak ACI (''Automatic Car Identification'') is a colored barcode system designed to automatically identify railcars and other rolling stock. KarTrak was made a requirement in North America, but technical problems led to the ...
railroad
Automatic Equipment Identification Automatic equipment identification (AEI) is an electronic recognition system in use with the North American railroad industry. Consisting of passive tags mounted on each side of rolling stock and active trackside readers, AEI uses RF technology t ...
label on a caboose in Florida


In popular culture

In architecture, a building in
Lingang New City Nanhui New City () is a planned city located in the Pudong New Area of Shanghai, China. It was formerly called Lingang New City (临港新城) until it was renamed in April 2012. Construction began in 2003 and is scheduled to be completed in 20 ...
by German architects Gerkan, Marg and Partners incorporates a barcode design, as does a shopping mall calle
''Shtrikh-kod''
(Russian for ''barcode'') in Narodnaya ulitsa ("People's Street") in the Nevskiy district of St. Petersburg, Russia. In media, in 2011, the
National Film Board of Canada The National Film Board of Canada (NFB; french: Office national du film du Canada (ONF)) is Canada's public film and digital media producer and distributor. An agency of the Government of Canada, the NFB produces and distributes documentary fi ...
and ARTE France launched a web documentary entitled ''Barcode.tv'', which allows users to view films about everyday objects by scanning the product's barcode with their iPhone camera. In
professional wrestling Professional wrestling is a form of theater that revolves around staged wrestling matches. The mock combat is performed in a ring similar to the kind used in boxing, and the dramatic aspects of pro wrestling may be performed both in the ring or ...
, the WWE stable D-Generation X incorporated a barcode into their entrance video, as well as on a T-shirt. In the TV series '' Dark Angel'', the protagonist and the other
transgenics A genetically modified organism (GMO) is any organism whose genetic material has been altered using genetic engineering techniques. The exact definition of a genetically modified organism and what constitutes genetic engineering varies, with ...
in the Manticore X-series have barcodes on the back of their necks. In video games, the protagonist of the ''Hitman'' video game series has a barcode tattoo on the back of his head; QR codes can also be scanned in a side mission in '' Watch Dogs''. The 2018 videogame '' Judgment'' features
QR Code A QR code (an initialism for quick response code) is a type of matrix barcode (or two-dimensional barcode) invented in 1994 by the Japanese company Denso Wave. A barcode is a machine-readable optical label that can contain information about t ...
s that protagonist Takayuki Yagami can photograph with his phone camera. These are mostly to unlock parts for Yagami's
Drone Drone most commonly refers to: * Drone (bee), a male bee, from an unfertilized egg * Unmanned aerial vehicle * Unmanned surface vehicle, watercraft * Unmanned underwater vehicle or underwater drone Drone, drones or The Drones may also refer to: ...
. In the films '' Back to the Future Part II'' and ''
The Handmaid's Tale ''The Handmaid's Tale'' is a futuristic dystopian novel by Canadian author Margaret Atwood and published in 1985. It is set in a near-future New England in a patriarchal, totalitarian theonomic state known as the Republic of Gilead, which ...
'', cars in the future are depicted with barcode licence plates. In the ''Terminator'' films, Skynet burns barcodes onto the inside surface of the wrists of captive humans (in a similar location to the WW2 concentration camp tattoos) as a unique identifier. In music, Dave Davies of The Kinks released a solo album in 1980, ''
AFL1-3603 ''AFL1-3603'' (aka Dave Davies) is an album released in 1980 by Dave Davies featuring Davies performing all the instruments. The album (named after its own serial number) peaked at number 42 on the Billboard 200 The ''Billboard'' 200 is a ...
'', which featured a giant barcode on the front cover in place of the musician's head. The album's name was also the barcode number. The April 1978 issue of ''
Mad Magazine Mad, mad, or MAD may refer to: Geography * Mad (village), a village in the Dunajská Streda District of Slovakia * Mád, a village in Hungary * Adolfo Suárez Madrid–Barajas Airport, by IATA airport code * Mad River (disambiguation), several ...
'' featured a giant barcode on the cover, with the blurb " adHopes this issue jams up every computer in the country...for forcing us to deface our covers with this yecchy UPC symbol from now on!" Interactive Textbooks were first published by ''Harcourt College Publishers to Expand Education Technology with Interactive Textbooks.''


Designed barcodes

Some brands integrate custom designs into barcodes (while keeping them readable) on their consumer products. File:Design Barcode Grasvodka IMG 5574.JPG File:Barcode Tall Horse1.jpg File:Hühner-Bouillon K Designbarcode 4337185009907 IMG 8716.jpg File:Sardinendose K Barcode Art valid IMG11829.jpg File:Barcode_peanut.jpg


Hoaxes about barcodes

There was minor skepticism from
conspiracy theorists A conspiracy theory is an explanation for an event or situation that invokes a conspiracy by sinister and powerful groups, often political in motivation, when other explanations are more probable.Additional sources: * * * * The term has a nega ...
, who considered barcodes to be an intrusive surveillance technology, and from some Christians, pioneered by a 1982 book ''The New Money System 666'' by Mary Stewart Relfe, who thought the codes hid the number
666 666 may refer to: * 666 (number) * 666 BC, a year * AD 666, a year * The number of the beast, a reference in the Book of Revelation in the New Testament Places * 666 Desdemona, a minor planet in the asteroid belt * U.S. Route 666, an America ...
, representing the "
Number of the Beast The number of the beast ( grc-koi, Ἀριθμὸς τοῦ θηρίου, ) is associated with the Beast of Revelation in chapter 13, verse 18 of the Book of Revelation. In most manuscripts of the New Testament and in English translations of t ...
". Old Believers, a separation of the
Russian Orthodox Church , native_name_lang = ru , image = Moscow July 2011-7a.jpg , imagewidth = , alt = , caption = Cathedral of Christ the Saviour in Moscow, Russia , abbreviation = ROC , type ...
, believe barcodes are the stamp of the Antichrist. Television host
Phil Donahue Phillip John Donahue (born December 21, 1935) is an American media personality, writer, film producer and the creator and host of ''The Phil Donahue Show''. The television program, later known simply as ''Donahue'', was the first talk show forma ...
described barcodes as a "corporate plot against consumers".


See also

* Automated identification and data capture (AIDC) * Barcode printer * Campus card * European Article Numbering-Uniform Code Council * Global Trade Item Number *
Identifier An identifier is a name that identifies (that is, labels the identity of) either a unique object or a unique ''class'' of objects, where the "object" or class may be an idea, physical countable object (or class thereof), or physical noncountable ...
* Inventory control system *
Object hyperlinking Object hyperlinking is a term that refers to extending the Internet to objects and locations in the real world. Object hyperlinking aims to extend the Internet to the physical world by attaching tags with URLs to tangible objects or locations. The ...
*
Semacode Semacode is a software company based in Waterloo, Ontario, Canada. It is also this company's trade name for their machine-readable ISO/IEC 16022 Data Matrix barcodes, which are used to encode Internet URLs. Semacodes are primarily aimed at b ...
* SMS barcode * SPARQCode (QR code) * List of GS1 country codes


References


Further reading

* ''Automating Management Information Systems: Barcode Engineering and Implementation'' – Harry E. Burke, Thomson Learning, * ''Automating Management Information Systems: Principles of Barcode Applications'' – Harry E. Burke, Thomson Learning, * ''The Bar Code Book'' – Roger C. Palmer, Helmers Publishing, , 386 pages * ''The Bar Code Manual'' – Eugene F. Brighan, Thompson Learning, * ''Handbook of Bar Coding Systems'' – Harry E. Burke, Van Nostrand Reinhold Company, , 219 pages * ''Information Technology for Retail:Automatic Identification & Data Capture Systems'' – Girdhar Joshi,
Oxford University Press Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print book ...
, , 416 pages * ''Lines of Communication'' – Craig K. Harmon, Helmers Publishing, , 425 pages * ''Punched Cards to Bar Codes'' – Benjamin Nelson, Helmers Publishing, , 434 pages * ''Revolution at the Checkout Counter: The Explosion of the Bar Code'' – Stephen A. Brown,
Harvard University Press Harvard University Press (HUP) is a publishing house established on January 13, 1913, as a division of Harvard University, and focused on academic publishing. It is a member of the Association of American University Presses. After the retir ...
, * ''Reading Between The Lines'' – Craig K. Harmon and Russ Adams, Helmers Publishing, , 297 pages * ''The Black and White Solution: Bar Code and the IBM PC'' – Russ Adams and Joyce Lane, Helmers Publishing, , 169 pages * ''Sourcebook of Automatic Identification and Data Collection'' – Russ Adams, Van Nostrand Reinhold, , 298 pages * ''Inside Out: The Wonders of Modern Technology'' – Carol J. Amato, Smithmark Pub, , 1993


External links

* {{Authority control Encodings Automatic identification and data capture 1952 introductions American inventions Records management technology