Barcode

A barcode is an optical machine-readable representation of data relating to the object to which it is attached. Originally barcodes systematically represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or one-dimensional (1D). Later they evolved into rectangles, dots, hexagons and other geometric patterns in two dimensions (2D). Although 2D systems use a variety of symbols, they are generally referred to as barcodes as well. Barcodes originally were scanned by special optical scanners called barcode readers. Later, scanners and interpretive software became available on devices including desktop printers and smartphones.

An early use of one type of barcode in an industrial context was sponsored by the Association of American Railroads in the late 1960s. Developed by General Telephone and Electronics (GTE) and called KarTrak ACI (Automatic Car Identification), this scheme involved placing colored stripes in various combinations on steel plates which were affixed to the sides of railroad rolling stock. Two plates were used per car, one on each side, with the arrangement of the colored stripes representing things such as ownership, type of equipment, and identification number.[1]  The plates were "read" by a trackside scanner located, for instance, at the entrance to a classification yard while the car was moving past.[2]  The project was abandoned after about ten years because the system proved unreliable after long-term use in the field.[1]

Barcodes became commercially successful when they were used to automate supermarket checkout systems, a task for which they have become almost universal. Their use has spread to many other tasks that are generically referred to as automatic identification and data capture (AIDC). The very first scanning of the now ubiquitous Universal Product Code (UPC) barcode was on a pack of Wrigley Company chewing gum in June 1974.[3]

Other systems have made inroads in the AIDC market, but the simplicity, universality and low cost of barcodes has limited the role of these other systems until the 2000s (decade), over 40 years after the introduction of the commercial barcode, with the introduction of technologies such as radio frequency identification, or RFID.



Contents
[hide]  *1 History  ==History[ edit] == 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.[4]  Silver told his friend Norman Joseph Woodland about the request, and they started working on a variety of systems. Their first working system used ultraviolet ink, but the ink faded too easily and was rather expensive.[5]
 * 1.1 Collins at Sylvania
 * 1.2 Computer Identics Corporation
 * 1.3 Universal Product Code
 * 2 Industrial adoption
 * 3 Use
 * 4 Symbologies
 * 5 Scanners (barcode readers)
 * 6 Quality control and verification
 * 6.1 Barcode verifier standards
 * 7 Benefits
 * 8 Types of barcodes
 * 8.1 Linear barcodes
 * 8.2 Matrix (2D) barcodes
 * 8.3 Example images
 * 9 In popular culture
 * 10 See also
 * 11 References
 * 11.1 Notes
 * 11.2 Bibliography
 * 12 External links

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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."<sup class="reference" id="cite_ref-story_5-1" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[5]  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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">On 20 October 1949 Woodland and Silver filed a patent application for "Classifying Apparatus and Method", in which they described both the linear and bullseye printing patterns, as well as the mechanical and electronic systems needed to read the code. The patent was issued on 7 October 1952 as US Patent 2,612,994. In 1951, Woodland moved to IBM and continually tried to interest IBM in developing the system. The company eventually commissioned a report on the idea, which concluded that it was both feasible and interesting, but that processing the resulting information would require equipment that was some time off in the future.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">IBM offered to buy the patent, but its offer was not high enough. Philco purchased their patent in 1962 and then sold it to RCA sometime later.<sup class="reference" id="cite_ref-story_5-2" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[5] ===Collins at Sylvania<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] === <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">During his time as an undergraduate, David 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 calledKarTrak 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.<sup class="reference" id="cite_ref-story_5-3" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[5]  Light reflected off the stripes was fed into one of two photomultipliers, filtered for blue or red.<sup class="noprint Inline-Template Template-Fact" style="line-height:1;font-size:11.1999998092651px;white-space:nowrap;">[citation needed]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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, theeconomic 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.<sup class="reference" id="cite_ref-6" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[6]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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 U.S. Post Office requested a system to track trucks entering and leaving their facilities. These applications required special retroreflector labels. Finally, Kal Kanasked the Sylvania team for a simpler (and cheaper) version which they could put on cases of pet food for inventory control. ===Computer Identics Corporation<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] === <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Collins then quit Sylvania and formed Computer Identics Corporation.<sup class="reference" id="cite_ref-story_5-4" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[5]  Computer Identics started working with helium–neon lasers in place of light bulbs, scanning with a mirror to locate the barcode anywhere up to several feet in front of the scanner. This made the entire process much simpler and more reliable, as well as allowing it to deal with damaged labels by reading the intact portions.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.<sup class="reference" id="cite_ref-story_5-5" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[5]  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<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] === Main article: Universal Product Code<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In 1966 the National Association of Food Chains (NAFC) held a meeting where they discussed the idea of automated checkout systems. RCA had purchased 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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In mid-1970s, the NAFC established the U.S. Supermarket Ad Hoc Committee on a Uniform Grocery Product Code, which set guidelines for barcode development and created a symbol selection subcommittee to help standardize the approach. In cooperation with consulting firm McKinsey & Co., they developed a standardized 11-digit code to identify any product. 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.<sup class="reference" id="cite_ref-7" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[7]  A wide variety of barcode approaches were studied, including linear codes, RCA's bullseye concentric circle code, starburst patterns and others.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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 North Carolina to lead development.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In July 1972 RCA began an eighteen-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. During printing, presses sometimes smear ink in the direction the paper is running, rendering the code unreadable in most orientations. A linear code, like the one being developed by Woodland at IBM, however, was printed in the direction of the stripes, so extra ink simply makes the code "taller" while remaining readable, and on 3 April 1973 the IBM UPC was selected by NAFC as their standard. IBM had designed five versions of the UPC symbology for future industry requirements: UPC A, B, C, D, and E.<sup class="reference" id="cite_ref-Nelson_8-0" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[8]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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 theSmithsonian Institution. It was the first commercial appearance of the UPC.<sup class="reference" id="cite_ref-Varchaver_9-0" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[9]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In 1971 IBM had assembled a team for an intensive planning session, day after day, 12 to 18 hours a day, to thrash out how the whole system might operate and to schedule a roll-out plan. By 1973 they 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 was projecting that 75% would be needed in 1975. Even though that was achieved, there were still scanning machines in fewer than 200 grocery stores by 1977.<sup class="reference" id="cite_ref-Selmeier_10-0" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[10]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.<sup class="noprint Inline-Template" style="line-height:1;font-size:11.1999998092651px;white-space:nowrap;">[who?]  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."<sup class="reference" id="cite_ref-Varchaver_9-1" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[9]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Experience with barcode scanning in those stores revealed additional benefits. The detailed sales information acquired by the new systems allowed greater responsiveness to customer needs. 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 also was a 1–2% decrease in operating cost for the stores that enabled them to lower prices to increase market share. It was shown in the field that the return on investment for a barcode scanner was 41.5%. By 1980, 8,000 stores per year were converting.<sup class="reference" id="cite_ref-Selmeier_10-1" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[10]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">The global public launch of the barcode<sup class="noprint Inline-Template" style="line-height:1;font-size:11.1999998092651px;white-space:nowrap;">[when?]  was greeted with minor skepticism from conspiracy theorists, who considered barcodes to be an intrusive surveillancetechnology, and from some Christians<sup class="noprint Inline-Template" style="line-height:1;font-size:11.1999998092651px;white-space:nowrap;">[when?]  who thought the codes hid the number 666, representing the number of the beast.<sup class="reference" id="cite_ref-11" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[11]  Television host Phil Donahuedescribed barcodes as a "corporate plot against consumers".<sup class="reference" id="cite_ref-12" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[12] ==Industrial adoption<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.<sup class="reference" id="cite_ref-13" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[13] ==Use<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Barcodes such as the UPC have become a ubiquitous element of modern civilization, as evidenced by their enthusiastic adoption by stores around the world; most items other than fresh produce from a grocery store now have UPC barcodes.<sup class="noprint Inline-Template Template-Fact" style="line-height:1;font-size:11.1999998092651px;white-space:nowrap;">[citation needed]  This helps track items and also reduces instances of shoplifting involving price tag swapping, although shoplifters can now print their own barcodes.<sup class="reference" id="cite_ref-14" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[14]  In addition, retail chain membership cards (issued mostly by grocery stores and specialty "big box" retail stores such as sporting equipment, office supply, or pet stores) use barcodes to uniquely identify consumers, allowing for customized marketing and greater understanding of individual consumer shopping patterns. At the point of sale, shoppers can get product discounts or special marketing offers through the address or e-mail address provided at registration.

Example of barcode on a patient identification wristband<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">They are widely used in the healthcare and hospital settings, ranging from patient identification (to access patient data, including medical history, drug allergies, etc.) to creating SOAP Notes<sup class="reference" id="cite_ref-15" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[15]  with barcodes to medication management. They are also used to facilitate the separation and indexing of documents that have been imaged in batch scanning applications, track the organization of species in biology,<sup class="reference" id="cite_ref-16" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[16]  and integrate with in-motion checkweighers to identify the item being weighed in aconveyor line for data collection.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">They can also be used to keep track of objects and people; they are used to keep track of rental cars, airline luggage, nuclear waste, registered mail, express mail and parcels. Barcoded tickets allow the holder to enter sports arenas, cinemas, theatres, fairgrounds, and transportation, and are used to record the arrival and departure of vehicles from rental facilities etc. This can allow proprietors to identify duplicate or fraudulent tickets more easily. Barcodes are widely used in shop floor control applications software where employees can scan work orders and track the time spent on a job.

Barcoded parcel<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Barcodes are also used in some kinds of non-contact 1D and 2D position sensors. A series of barcodes are used in some kinds of absolute 1D linear encoder. The barcodes are packed close enough together that the reader always has one or two barcodes in its field of view. The relative position of the barcode in the field of view of the reader gives incremental precise positioning, in some cases with sub-pixel resolution. The data decoded from the barcode gives the absolute coarse position. An "address carpet", such as 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.<sup class="reference" id="cite_ref-17" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[17] <sup class="reference" id="cite_ref-18" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[18]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Some 2D barcodes embed a hyperlink to a web page. A capable cellphone might be used to read the pattern and browse the linked website, which can help a shopper find the best price for an item in the vicinity. Since 2005, airlines use an IATA-standard 2D barcode on boarding passes (Bar Coded Boarding Pass (BCBP)), and since 2008 2D barcodes sent to mobile phones enable electronic boarding passes.<sup class="reference" id="cite_ref-19" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[19]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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<sup class="reference" id="cite_ref-20" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[20]  are barcode symbologies specifically designed for this application), and the 1991 Barcode Battler computer game system used any standard barcode to generate combat statistics.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In the 21st century, many artists have started using barcodes in art, such as Scott Blake's Barcode Jesus, as part of the post-modernism movement. ==Symbologies<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">The mapping between messages and barcodes is called a symbology. The specification of a symbology includes the encoding of the single digits/characters of the message as well as the start and stop markers into bars and space, the size of the quiet zone required to be before and after the barcode as well as the computation of a checksum.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Linear symbologies can be classified mainly by two properties:

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.
 * Continuous vs. discrete: Characters in continuous symbologies usually abut, with one character ending with a space and the next beginning with a bar, or vice versa. Characters in discrete symbologies begin and end with bars; the intercharacter space is ignored, as long as it is not wide enough to look like the code ends.
 * Two-width vs. many-width: Bars and spaces in two-width symbologies are wide or narrow; the exact width of a wide bar has no significance as long as the symbology requirements for wide bars are adhered to (usually two to three times wider than a narrow bar). 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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Stacked symbologies repeat a given linear symbology vertically.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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).

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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. Stacked symbologies are also optimized for laser scanning, with the laser making multiple passes across the barcode.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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. ==Scanners (barcode readers)<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == Main article: Barcode reader<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">The earliest, and still the cheapest, barcode scanners are built from a fixed light and a single photosensor that is manually "scrubbed" across the barcode.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">"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.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Like the keyboard interface scanner, USB scanners are easy to install and do not need custom code for transferring input data to the application program. On PCs running Windows the HID interface emulates the data merging action of a hardware "keyboard wedge", and the scanner automatically behaves like an additional keyboard.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Many phones are able to decode barcodes using their built-in camera, as well. Google's mobile Android operating system uses both their own Google Gogglesapplication or third party barcode scanners like Scan.<sup class="reference" id="cite_ref-21" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[21]  Nokia's Symbian operating system features a barcode scanner,<sup class="reference" id="cite_ref-22" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[22]  while mbarcode<sup class="reference" id="cite_ref-23" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[23]  is a QR code reader for the Maemo operating system. In the Apple iOS, a barcode reader is not natively included but more than fifty paid and free apps are available with both scanning capabilities and hard-linking to URI. With BlackBerry devices, the App World application can natively scan barcodes and load any recognized Web URLs on the 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. ==Quality control and verification<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Barcode verification examines scanability and the quality of the barcode in comparison to industry standards and specifications. Barcode verifiers are primarily used by businesses that print and use barcodes. Any trading partner in the supply chain can test barcode quality. It is important to verify a barcode to ensure that any reader in the supply chain can successfully interpret a barcode with a low error rate. Retailers levy large penalties for non-compliant barcodes. These chargebacks can reduce a manufacturer's revenue by 2% to 10%.<sup class="reference" id="cite_ref-24" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[24]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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:

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">2D matrix symbols look at the parameters:
 * Edge Determination
 * Minimum Reflectance
 * Symbol Contrast
 * Minimum Edge Contrast
 * Modulation
 * Defects
 * Decode
 * Decodability

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Depending on the parameter, each ANSI test is graded from 0.0 to 4.0 (F to A), or given a pass or fail mark. Each grade is determined by analyzing the scan reflectance profile (SRP), an analog graph of a single scan line across the entire symbol. The lowest of the 8 grades is the scan grade and the overall ISO symbol grade is the average of the individual scan grades. For most applications a 2.5 (C) is the minimum acceptable symbol grade.<sup class="reference" id="cite_ref-26" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[26]
 * Symbol Contrast
 * Modulation
 * Decode
 * Unused Error Correction
 * Fixed (finder) Pattern Damage
 * Grid Non-uniformity
 * Axial Non-uniformity<sup class="reference" id="cite_ref-25" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[25]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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. ===Barcode verifier standards<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] === <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">This standard defines the measuring accuracy of a barcode verifier.
 * Barcode verifiers should comply with the ISO/IEC 15416 (linear)] or ISO/IEC 15426-2 (2D).

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">This standard defines the quality requirements for barcodes and Matrix Codes (also called Optical Codes).
 * 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).

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">International standards are available from the International Organization for Standardization (ISO).<sup class="reference" id="cite_ref-28" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[28]
 * As of 2011 the ISO workgroup JTC1 SC31 was developing a Direct Part Marking (DPM) quality standard : ISO/IEC TR 29158.<sup class="reference" id="cite_ref-27" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[27]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">These standards are also available from local/national standardization organizations, such as ANSI, BSI, DIN, NEN and others. ==Benefits<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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:

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">Besides sales and inventory tracking, barcodes are very useful in logistics and supply chain management.
 * 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.

<p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">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.<sup class="reference" id="cite_ref-29" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[29] <sup class="noprint Inline-Template" style="line-height:1;font-size:11.1999998092651px;white-space:nowrap;">[unreliable source?]  The exact error rate depends on the type of barcode. ==Types of barcodes<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == ===Linear barcodes<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] === <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">A first generation, "one dimensional" barcode that is made up of lines and spaces of various widths that create specific patterns. ===Matrix (2D) barcodes<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] === <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">A matrix code, also termed a 2D barcode 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<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] ===
 * 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.
 * First, Second and Third Generation Barcodes
 * <p style="margin-top:0.5em;line-height:inherit;">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
 * <p style="margin-top:0.5em;line-height:inherit;">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


 * <p style="margin-top:0.5em;line-height:inherit;">"Wikipedia" encoded inCode 93


 * <p style="margin-top:0.5em;line-height:inherit;">"*WIKI39*" encoded inCode 39


 * <p style="margin-top:0.5em;line-height:inherit;">'Wikipedia" encoded inCode 128


 * <p style="margin-top:0.5em;line-height:inherit;">An example of a stacked barcode. Specifically a "Codablock" barcode.


 * <p style="margin-top:0.5em;line-height:inherit;">PDF417 sample


 * <p style="margin-top:0.5em;line-height:inherit;">Lorem ipsum boilerplate text as four segmentData Matrix 2D


 * <p style="margin-top:0.5em;line-height:inherit;">"This is an example Aztec symbol for Wikipedia" encoded inAztec Code


 * <p style="margin-top:0.5em;line-height:inherit;">Text 'EZcode'


 * <p style="margin-top:0.5em;line-height:inherit;">High Capacity Color Barcode of the URL for Wikipedia's article onHigh Capacity Color Barcode


 * <p style="margin-top:0.5em;line-height:inherit;">"Wikipedia, The Free Encyclopedia" in several languages encoded inDataGlyphs


 * <p style="margin-top:0.5em;line-height:inherit;">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 Soundin the blue area to the left of the sprocket holes


 * <p style="margin-top:0.5em;line-height:inherit;">The QR Code for the Wikipedia URL. "Quick Response", the most popular 2D barcode in Japan, is promoted by Google. It is open in that the specification is disclosed and the patent is not exercised.<sup class="reference" id="cite_ref-46" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:10.3999996185303px;">[46]


 * <p style="margin-top:0.5em;line-height:inherit;">MaxiCode example. This encodes the string "Wikipedia, The Free Encyclopedia"


 * <p style="margin-top:0.5em;line-height:inherit;">ShotCode sample


 * <p style="margin-top:0.5em;line-height:inherit;">detail of Twibright Optarscan from laser printed paper, carrying 32 kbit/s Ogg Vorbis digital music (48 seconds per A4 page)

==In popular culture<span class="mw-editsection" style="-webkit-user-select:none;font-size:small;margin-left:1em;line-height:1em;display:inline-block;white-space:nowrap;unicode-bidi:-webkit-isolate;font-family:sans-serif;"><span class="mw-editsection-bracket" style="color:rgb(85,85,85);">[ edit<span class="mw-editsection-bracket" style="color:rgb(85,85,85);">] == <p style="margin-top:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In architecture, a building in Lingang New City by German architects Gerkan, Marg and Partners incorporates a barcode design,<sup class="reference" id="cite_ref-47" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[47]  as does a shopping mall calledShtrikh-kod (the Russian for barcode) in Narodnaya ulitsa ("People's Street") in the Nevskiy district of St. Petersburg, Russia.<sup class="reference" id="cite_ref-48" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[48]
 * <p style="margin-top:0.5em;line-height:inherit;">A KarTrak railroadAutomatic Equipment Identification label on a caboose in Florida

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In media, 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.<sup class="reference" id="cite_ref-NFB_blog_49-0" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[49] <sup class="reference" id="cite_ref-Reelscreen_50-0" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[50]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In professional wrestling, the WWE stable D-Generation X incorporated a barcode into their entrance video, as well as on a T-shirt.<sup class="reference" id="cite_ref-51" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[51] <sup class="reference" id="cite_ref-52" style="line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[52]

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In video games, the protagonist of the Hitman video game series has a barcode tattoo on the back of his head.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In the films Back to the Future Part II and The Handmaid's Tale, cars in the future are depicted with barcode licence plates.

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:17.9200000762939px;color:rgb(37,37,37);font-family:sans-serif;font-size:14.3999996185303px;">In music, Dave Davies of The Kinks released a solo album in 1980, AFL1-3603, 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.