Barcode#Matrix (2D) barcodes

{{duplication|dupe=Universal Product Code#History|date=December 2013}}

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.{{cite news|date=1 August 2001 |title=The Killer App – Bar None |url=http://www.americanwaymag.com/so-woodland-bar-code-bernard-silver-drexel-university |first=Charles |last=Fishman |work=American Way |access-date=19 April 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100112043409/http://www.americanwaymag.com/so-woodland-bar-code-bernard-silver-drexel-university |archive-date=12 January 2010 }} 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 expensive.{{Citation |first=Tony |last=Seideman |title=Barcodes Sweep the World |work=Wonders of Modern Technology |url=http://www.bar-code.com/upc/bar_code_history.php |archive-url=https://web.archive.org/web/20161016084435/http://www.bar-code.com/upc/bar_code_history.php|archive-date=16 October 2016|url-status=dead|date=Spring 1993}}

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, 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.

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, white and red reflective stripes attached to the side of the cars, encoding a four-digit company identifier and a six-digit car number. Light reflected off the colored stripes was read by photomultiplier vacuum tubes.{{cite web | url =https://www.technologyreview.com/s/601032/david-collins-sm-59/ | title =David Collins, SM '59: Making his mark on the world with bar codes | last =Dunn | first =Peter | date =20 October 2015 | website =technologyreview.com | publisher =MIT | access-date =2 December 2019 | archive-date =10 November 2018 | archive-url =https://web.archive.org/web/20181110013152/https://www.technologyreview.com/s/601032/david-collins-sm-59/ | url-status =live }}

The Boston and Maine Railroad 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, 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.{{cite journal |last=Graham-White|first=Sean |date=August 1999|title=Do You Know Where Your Boxcar Is?|journal=Trains |volume=59 |issue=8 |pages=48–53 }}

The railway project had failed, but a toll bridge in New Jersey requested a similar system so that it could quickly scan for cars that had purchased a monthly pass. Then the US Post Office requested a system to track trucks entering and leaving their facilities. These applications required special retroreflector 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.

In 1967, with the railway 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 a meter (3 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 (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.

{{Main|Universal Product Code}}

In 1966 the National Association of Food Chains (NAFC) held a meeting on the idea of automated checkout systems. RCA, which 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), Litton Industries, RCA, Pitney-Bowes, IBM and many others.{{cite web |first=George |last=Laurer |author-link=George Laurer |url=http://bellsouthpwp.net/l/a/laurergj/UPC/upc_work.html |title=Development of the U.P.C. Symbol |archive-url=https://web.archive.org/web/20080925105745/http://bellsouthpwp.net/l/a/laurergj/UPC/upc_work.html |archive-date=25 September 2008 }} A wide variety of barcode approaches was studied, including linear codes, RCA's bullseye concentric circle code, starburst 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 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.{{cite book | last = Nelson | first = Benjamin | year = 1997 | title = Punched Cards To Bar Codes: A 200-year journey |publisher=Helmers |location=Peterborough, N.H. |isbn=9780911261127}}

NCR installed a testbed system at Marsh's Supermarket in Troy, Ohio, near the factory that was producing the equipment. On 26 June 1974, a 10-pack of Wrigley's Juicy Fruit gum was scanned, registering the first commercial use of the UPC.{{cite journal | last = Varchaver | first = Nicholas | date = 31 May 2004 | title = Scanning the Globe | journal = Fortune | url = https://money.cnn.com/magazines/fortune/fortune_archive/2004/05/31/370719/index.htm | access-date = 27 November 2006 | archive-url= https://web.archive.org/web/20061114065720/https://money.cnn.com/magazines/fortune/fortune_archive/2004/05/31/370719/index.htm| archive-date= 14 November 2006 | url-status= live}}

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.

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.{{cite news| url= https://www.nytimes.com/2010/02/28/t-magazine/womens-fashion/28talk-rawsthorn.html| title= Scan Artists| work= New York Times| last= Rawsthorn| first= Alice| date= 23 February 2010| access-date= 31 July 2015| archive-date= 18 November 2016| archive-url= https://web.archive.org/web/20161118202704/http://www.nytimes.com/2010/02/28/t-magazine/womens-fashion/28talk-rawsthorn.html?_r=0| url-status= live}}

Sims Supermarkets were the first location in Australia to use barcodes, starting in 1979.{{cite web|title=World hails barcode on important birthday|url=http://www.fullyloaded.com.au/news/logistics/1407/world-hails-barcode-on-important-birthday/|website=ATN|date=1 July 2014|access-date=15 February 2017|archive-date=23 July 2014|archive-url=https://web.archive.org/web/20140723051540/http://www.fullyloaded.com.au/news/logistics/1407/world-hails-barcode-on-important-birthday/|url-status=live}}

A barcode system is a network of hardware and software, consisting primarily of mobile computers, printers, handheld scanners, infrastructure, and supporting software. Barcode systems are used to automate data collection where hand recording is neither timely nor cost effective. Despite often being provided by the same company, Barcoding systems are not radio-frequency identification (RFID) systems. Many companies use both technologies as part of larger resource management systems.

A typical barcode system consist of some infrastructure, either wired or wireless that connects some number of mobile computers, handheld scanners, and printers to one or many databases that store and analyze the data collected by the system. At some level there must be some software to manage the system. The software may be as simple as code that manages the connection between the hardware and the database or as complex as an ERP, MRP, or some other inventory management software.

A wide range of hardware is manufactured for use in barcode systems by such manufacturers as Datalogic, Intermec, HHP (Hand Held Products), Microscan Systems, Unitech, Metrologic, PSC, and PANMOBIL, with the best known brand of handheld scanners and mobile computers being produced by Symbol,{{citation needed|date=October 2024}} a division of Motorola.

Some ERP, MRP, and other inventory management software have built in support for barcode reading. Alternatively, custom interfaces can be created using a language such as C++, C#, Java, Visual Basic.NET, and many others. In addition, software development kits are produced to aid the process.

In 1981 the United States Department of Defense adopted the use of Code 39 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.{{cite web |url=http://www.adams1.com/history.html |title=A Short History of Bar Code |website=BarCode 1 |publisher=Adams Communications |access-date=28 November 2011 |archive-date=2 May 2010 |archive-url=https://web.archive.org/web/20100502072956/http://www.adams1.com/history.html |url-status=live }}

File:Snack vendor on the Shinkansen. 2005 (26321781190).jpg train scans a barcode.]]

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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. This speeds up processing at check-outs and helps track items and also reduces instances of shoplifting involving price tag swapping, although shoplifters can now print their own barcodes.{{cite web |url=http://iwatchsystems.com/technical/2011/05/02/barcode/ |title=Barcode |website=iWatch Systems |date=2 May 2011 |access-date=28 November 2011 |archive-date=9 January 2012 |archive-url=https://web.archive.org/web/20120109011439/http://iwatchsystems.com/technical/2011/05/02/barcode/ |url-status=live }} Barcodes that encode a book's ISBN 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 healthcare and hospital settings, ranging from patient identification (to access patient data, including medical history, drug allergies, etc.) to creating SOAP notes{{cite web|last=Oberfield|first=Craig|title=QNotes Barcode System|url=http://www.qnotes.com/quix/|work=US Patented #5296688|publisher=Quick Notes Inc.|access-date=15 December 2012|archive-date=31 December 2012|archive-url=https://web.archive.org/web/20121231170857/http://qnotes.com/quix/|url-status=live}} 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,National Geographic, May 2010, page 30 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, express mail, 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 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. As a kind of fiducial marker, 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", used in digital paper, 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.{{cite journal |first=David L. |last=Hecht |url=http://jupiter.plymouth.edu/~wjt/HCI/ui2.pdf |title=Printed Embedded Data Graphical User Interfaces |archive-url=https://web.archive.org/web/20130603223227/http://turing.plymouth.edu/~wjt/HCI/ui2.pdf |archive-date=3 June 2013| publisher=Xerox Palo Alto Research Center |journal=IEEE Computer |date=March 2001|volume=34 |issue=3 |pages=47–55 |doi=10.1109/2.910893 }}{{cite web |first1=Jon |last1=Howell |first2=Keith |last2=Kotay |url=http://www.cs.dartmouth.edu/reports/abstracts/TR2000-364/ |title=Landmarks for absolute localization |website=Dartmouth Computer Science Technical Report TR2000-364 |date=March 2000

|archive-url=https://web.archive.org/web/20201001131924/http://www.cs.dartmouth.edu/reports/TR2000-364.pdf

|archive-date=2020-10-01

}}

Matrix codes can embed a hyperlink to a web page. A mobile device with a built-in 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.{{cite web |url=http://www.iata.org/ |title=IATA.org |publisher=IATA.org |date=21 November 2011 |access-date=28 November 2011 |archive-date=4 January 2012 |archive-url=https://web.archive.org/web/20120104081606/http://www1.iata.org/ |url-status=live }}

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{{cite news |url=http://primepuzzle.com/waduzitdo/waduzitdo.html |title=Paperbyte Bar Codes for Waduzitdo |work=Byte magazine |date=September 1978 |page=172 |access-date=6 February 2009 |archive-date=4 July 2017 |archive-url=https://web.archive.org/web/20170704113826/http://primepuzzle.com/waduzitdo/waduzitdo.html |url-status=live }} are barcode symbologies specifically designed for this application), and the 1991 Barcode Battler 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 movement.

The mapping between messages and barcodes is called a symbology. 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 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. 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.

{{Main|Barcode reader}}

File:GTIN Barcodes of coke bottles - what you see and what the barcode scanner see 2 IMG 2908 2913 2919.JPG barcodes on Coca-Cola bottles. The images at right show how the laser of barcode readers "see" the images behind a red filter.]]

The earliest, and still{{when|date=September 2022}} 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 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 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. Google's Pixel devices can natively read QR codes inside the default Pixel Camera app. Nokia's Symbian operating system featured a barcode scanner,{{cite web |url=http://europe.nokia.com/support/product-support/nokia-n80/phone-software/smartphone |website=Nokia Europe |title=Nokia N80 Support |archive-url=https://web.archive.org/web/20110714030851/http://europe.nokia.com/support/product-support/nokia-n80/phone-software/smartphone |archive-date=14 July 2011 |url-status=dead}} while mbarcode{{cite web |url=http://maemo.org/packages/view/mbarcode/ |title=package overview for mbarcode |publisher=Maemo.org |access-date=28 July 2010 |archive-date=7 April 2019 |archive-url=https://web.archive.org/web/20190407120644/http://maemo.org/packages/view/mbarcode/ |url-status=live }} is a QR code reader for the Maemo operating system. In Apple iOS 11, 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.{{cite web |url=https://www.imore.com/how-use-qr-codes-ios-11 |access-date=1 October 2017 |title=How to use QR codes in iOS 11 |publisher=iMore |first=Mikah |last=Sargent |date=24 September 2017 |archive-date=2 October 2017 |archive-url=https://web.archive.org/web/20171002120404/https://www.imore.com/how-use-qr-codes-ios-11 |url-status=live }} Other paid and free apps are available with scanning capabilities for other symbologies or for earlier iOS versions.{{cite web |url=https://www.iphoneness.com/iphone-apps/5-best-barcode-iphone-applications/ |access-date=1 October 2017 |title=15+ Best Barcode Scanner iPhone Applications |website=iPhoneness |date=3 March 2017 |archive-date=2 October 2017 |archive-url=https://web.archive.org/web/20171002120130/https://www.iphoneness.com/iphone-apps/5-best-barcode-iphone-applications/ |url-status=live }} With BlackBerry 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.{{citation needed|date=February 2020}}

It is common for producers and users of bar codes to have a quality management system which includes verification and validation of bar codes.{{citation

| last =David

| first =H

| title =Barcodes – Validation vs Verification in GS1

| journal =Labeling News

| date =28 November 2018

| url =http://www.labelingnews.com/2018/11/barcodes-validation-vs-verification-in-gs1/

| access-date =6 June 2020

| archive-date =7 June 2020

| archive-url =https://web.archive.org/web/20200607173051/http://www.labelingnews.com/2018/11/barcodes-validation-vs-verification-in-gs1/

| url-status =live

}} Barcode verification examines scanability and the quality of the barcode in comparison to industry standards and specifications.{{cite web

|url= https://www.bar-code.com/verifiers/LaymansGuidetoANSI.pdf

|title= Layman's Guide to ANSI, CEN, and ISO Barcode Print Quality Documents

|publisher= Association for Automatic Identification and Data Capture Technologies (AIM)

|date= 2002

|access-date= 23 November 2017

|archive-date= 10 September 2016

|archive-url= https://web.archive.org/web/20160910162109/http://www.bar-code.com/verifiers/LaymansGuidetoANSI.pdf

|url-status= dead

}} 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 manufacturer's revenue by 2% to 10%.{{cite journal|last=Zieger |first=Anne |title=Retailer chargebacks: is there an upside? Retailer compliance initiatives can lead to efficiency |journal=Frontline Solutions |date=October 2003 |url=http://findarticles.com/p/articles/mi_m0DIS/is_10_4/ai_109518393/ |archive-url=https://archive.today/20120708192857/http://findarticles.com/p/articles/mi_m0DIS/is_10_4/ai_109518393/ |url-status=dead |archive-date=8 July 2012}}

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){{Cite web|url=https://www.expresscorp.com/Barcode-Glossary|title=Barcode Glossary {{!}} Express|last=Corp|first=Express|website=Express Corp|language=en|access-date=11 December 2019|archive-date=11 December 2019|archive-url=https://web.archive.org/web/20191211231342/https://www.expresscorp.com/Barcode-Glossary|url-status=live}}
• 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{{cite journal|author=Bar Code Verification Best Practice work team|title=GS1 DataMatrix: An introduction and technical overview of the most advanced GS1 Application Identifiers compliant symbology|journal=Global Standards 1|date=May 2010|volume=1|issue=17|pages=34–36|url=http://www.gs1.org/docs/barcodes/GS1_DataMatrix_Introduction_and_technical_overview.pdf|access-date=2 August 2011| archive-url= https://web.archive.org/web/20110720135555/http://www.gs1.org/docs/barcodes/GS1_DataMatrix_Introduction_and_technical_overview.pdf| archive-date= 20 July 2011 | url-status= live}}

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.{{cite journal|author=GS1 Bar Code Verification Best Practice work team|title=GS1 Bar Code Verification for Linear Symbols|journal=Global Standards 1|volume=4|date=May 2009|issue=3|pages=23–32|url=http://www.gs1.org/docs/barcodes/GS1_Bar_Code_Verification.pdf|access-date=2 August 2011|archive-date=27 September 2011|archive-url=https://web.archive.org/web/20110927053101/http://www.gs1.org/docs/barcodes/GS1_Bar_Code_Verification.pdf|url-status=live}}

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. 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.{{citation

| last =Garner

| first =J

| title =Results of Data Matrix Barcode Testing for Field Applications

| publisher =Oak Ridge National Laboratory

| date = 2019

| url = https://www.osti.gov/servlets/purl/1524857

| access-date =6 June 2020

}}

Barcode verifier standards are defined by the International Organization for Standardization (ISO), in ISO/IEC 15426-1 (linear) or ISO/IEC 15426-2 (2D).{{citation needed|date=February 2020}} The current international barcode quality specification is ISO/IEC 15416 (linear) and ISO/IEC 15415 (2D).{{citation needed|date=February 2020}} 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).{{citation needed|date=February 2020}} As of 2011 the ISO workgroup JTC1 SC31 was developing a Direct Part Marking (DPM) quality standard: ISO/IEC TR 29158.{{cite web |url=http://www.iso.org/iso/iso_technical_committee.html?commid=45332 |title=Technical committees – JTC 1/SC 31 – Automatic identification and data capture techniques |date=4 December 2008 |publisher=ISO |access-date=28 November 2011 |archive-date=18 October 2011 |archive-url=https://web.archive.org/web/20111018171042/http://www.iso.org/iso/iso_technical_committee.html?commid=45332 |url-status=live }}

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.{{which|date=March 2019}}

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.{{cite book |first1=Craig K. |last1=Harmon |first2=Russ |last2=Adams |date=1989 |title=Reading Between The Lines:An Introduction to Bar Code Technology |page=13 |publisher=Helmers |location=Peterborough, NH |isbn=0-911261-00-1}}{{Unreliable source?|date=July 2010}} The exact error rate depends on the type of barcode.

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

2D barcodes consist of bars, but use both dimensions for encoding.

==={{anchor|2D Codes}} Matrix (2D) codes===

A matrix code or simply a 2D code, is a two-dimensional way to represent information. It can represent more data per unit area. Apart from dots various other patterns can be used.

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

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 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

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 between the sprocket holes with the "Double-D" logo in the middle, and Sony Dynamic Digital Sound in the blue area to the left of the sprocket holes

File:WikiQRCode.svg|The QR code 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.[http://www.denso-wave.com/qrcode/qrstandard-e.html (株)デンソーウェーブ] {{Webarchive|url=https://web.archive.org/web/20120607102221/http://www.denso-wave.com/qrcode/qrstandard-e.html |date=7 June 2012 }}, denso-wave.com {{in lang|ja}} Copyright

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 railroad Automatic Equipment Identification label on a caboose in Florida

In architecture, a building in Lingang New City by German architects Gerkan, Marg and Partners incorporates a barcode design,{{Cite web |date=2009 |title=Barcode Halls, Standard Facades for Manufacturing Buildings – Projects – gmp Architekten |url=https://www.gmp.de/en/projects/549/barcode-halls-standard-facades-for-manufacturing-buildings |url-status=live |archive-url=https://web.archive.org/web/20231216013407/https://www.gmp.de/en/projects/549/barcode-halls-standard-facades-for-manufacturing-buildings |archive-date=2023-12-16 |access-date=2023-12-16 |website=www.gmp.de |language=en}} as does a shopping mall called Shtrikh-kod (Russian for barcode) in Narodnaya ulitsa ("People's Street") in the Nevskiy district of St. Petersburg, Russia.{{cite web |url=http://peterburg2.ru/restplaces/2530.html |title=image |publisher=Peterburg2.ru |access-date=28 November 2011 |archive-date=10 November 2011 |archive-url=https://web.archive.org/web/20111110051507/http://peterburg2.ru/restplaces/2530.html |url-status=live }}

In media, in 2011, the National Film Board of Canada 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.{{cite web|last=Lavigne|first=Anne-Marie|title=Introducing Barcode.tv, a new interactive doc about the objects that surround us|url=http://blog.nfb.ca/2011/10/05/introducing-barcode/|work=NFB Blog|publisher=National Film Board of Canada|access-date=7 October 2011|date=5 October 2011|archive-date=11 October 2011|archive-url=https://web.archive.org/web/20111011174058/http://blog.nfb.ca/2011/10/05/introducing-barcode/|url-status=live}}{{cite news|last=Anderson|first=Kelly|title=NFB, ARTE France launch 'Bar Code'|url=http://realscreen.com/2011/10/06/nfb-and-arte-france-launch-bar-code/|access-date=7 October 2011|newspaper=Reelscreen|date=6 October 2011|archive-date=10 October 2011|archive-url=https://web.archive.org/web/20111010041947/http://realscreen.com/2011/10/06/nfb-and-arte-france-launch-bar-code/|url-status=live}}

In professional wrestling, the WWE stable D-Generation X incorporated a barcode into their entrance video, as well as on a T-shirt.[http://www.attitudetees.com/items/dxbarcode.html] {{webarchive|url=https://web.archive.org/web/20150316205717/http://www.attitudetees.com/items/dxbarcode.html|date=16 March 2015}}{{cite web|url=https://www.youtube.com/watch?v=BkvplmOtmX4 |archive-url=https://ghostarchive.org/varchive/youtube/20211211/BkvplmOtmX4| archive-date=2021-12-11 |url-status=live|title=Dx theme song 2009–2010 |publisher=YouTube |date=19 December 2009 |access-date=10 March 2014}}{{cbignore}}

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 Codes that protagonist Takayuki Yagami can photograph with his phone camera. These are mostly to unlock parts for Yagami's Drone.{{cite web |url=https://www.eurogamer.net/articles/2019-06-26-judgment-qr-codes-drone-parts-6032 |author=Diego Agruello |date=27 June 2019 |access-date=3 August 2019 |title=Judgment QR code locations to upgrade Drone Parts explained • Eurogamer.net |website=Eurogamer |archive-date=28 August 2019 |archive-url=https://web.archive.org/web/20190828223321/https://www.eurogamer.net/articles/2019-06-26-judgment-qr-codes-drone-parts-6032 |url-status=live }}

Interactive Textbooks were first published by Harcourt College Publishers to Expand Education Technology with Interactive Textbooks.{{Cite web|url=https://cuecat.org/|title=CueCat History|website=CueCat History|language=en|access-date=12 November 2019|archive-date=12 November 2019|archive-url=https://web.archive.org/web/20191112235022/https://cuecat.org/|url-status=live}}

Some companies integrate custom designs into barcodes on their consumer products without impairing their readability.

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

Some have regarded barcodes to be an intrusive surveillance technology. Some Christians, pioneered by a 1982 book The New Money System 666 by Mary Stewart Relfe, believe the codes hide the number 666, representing the "Number of the beast".{{cite web |url=http://www.av1611.org/666/barcode.html |title=What about barcodes and 666: The Mark of the Beast? |publisher=Av1611.org |year=1999 |access-date=14 March 2014 |archive-date=27 November 2013 |archive-url=https://web.archive.org/web/20131127041006/http://www.av1611.org/666/barcode.html |url-status=live }} Old Believers, a separation of the Russian Orthodox Church, believe barcodes are the stamp of the Antichrist.{{cite web |title=The Russian Family That Cut Itself Off From Civilization for More Than 40 Years |url=https://www.mentalfloss.com/article/551659/karp-lykov-russian-family-secluded-from-civilization-40-years |publisher=Mental Floss |first=Jay |last=Serafino |date=26 July 2018 |access-date=6 May 2020 |archive-date=7 May 2020 |archive-url=https://web.archive.org/web/20200507041702/https://www.mentalfloss.com/article/551659/karp-lykov-russian-family-secluded-from-civilization-40-years |url-status=live }} Television host Phil Donahue described barcodes as a "corporate plot against consumers".{{cite web|url=http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2004/07/05/BUG6Q7G4AJ1.DTL&type=business |archive-url=https://web.archive.org/web/20040823004929/http://www.sfgate.com/cgi-bin/article.cgi?file=%2Fchronicle%2Farchive%2F2004%2F07%2F05%2FBUG6Q7G4AJ1.DTL&type=business |archive-date=23 August 2004 |title=UPC bar code has been in use 30 years |last=Bishop |first=Tricia |publisher=SFgate.com |date=5 July 2004 |access-date=22 December 2009 |url-status=dead }}

{{div col}}

• Automated identification and data capture (AIDC)
• Barcode printer
• Campus card
• European Article Numbering-Uniform Code Council
• Global Trade Item Number
• Identifier
• Inventory control system
• Object hyperlinking
• Semacode
• SPARQCode (QR code)
• List of GS1 country codes

{{div col end}}

{{Reflist|30em}}

{{Commons category|Barcode}}

{{refbegin}}

• Automating Management Information Systems: Barcode Engineering and Implementation – Harry E. Burke, Thomson Learning, {{ISBN|0-442-20712-3}}
• Automating Management Information Systems: Principles of Barcode Applications – Harry E. Burke, Thomson Learning, {{ISBN|0-442-20667-4}}
• The Bar Code Book – Roger C. Palmer, Helmers Publishing, {{ISBN|0-911261-09-5}}, 386 pages
• The Bar Code Manual – Eugene F. Brighan, Thompson Learning, {{ISBN|0-03-016173-8}}
• Handbook of Bar Coding Systems – Harry E. Burke, Van Nostrand Reinhold Company, {{ISBN|978-0-442-21430-2}}, 219 pages
• Information Technology for Retail:Automatic Identification & Data Capture Systems – Girdhar Joshi, Oxford University Press, {{ISBN|0-19-569796-0}}, 416 pages
• Lines of Communication – Craig K. Harmon, Helmers Publishing, {{ISBN|0-911261-07-9}}, 425 pages
• Punched Cards to Bar Codes – Benjamin Nelson, Helmers Publishing, {{ISBN|0-911261-12-5}}, 434 pages
• Revolution at the Checkout Counter: The Explosion of the Bar Code – Stephen A. Brown, Harvard University Press, {{ISBN|0-674-76720-9}}
• Reading Between The Lines – Craig K. Harmon and Russ Adams, Helmers Publishing, {{ISBN|0-911261-00-1}}, 297 pages
• The Black and White Solution: Bar Code and the IBM PC – Russ Adams and Joyce Lane, Helmers Publishing, {{ISBN|0-911261-01-X}}, 169 pages
• Sourcebook of Automatic Identification and Data Collection – Russ Adams, Van Nostrand Reinhold, {{ISBN|0-442-31850-2}}, 298 pages
• Inside Out: The Wonders of Modern Technology – Carol J. Amato, Smithmark Pub, {{ISBN|0831746572}}, 1993

{{refend}}

{{Barcodes}}

{{Paper data storage media}}

{{Authority control}}

Category:Encodings

Category:Automatic identification and data capture

Category:1952 introductions

Category:American inventions

Category:Records management technology