The barcode (besides universal product code) occurs as machine-readable representatiin of information inside the ocular format on the surface. Originally barcodes stored information around the breadth & spacings of printed parallel lines, however now it too are around system of dots, homocentric circles, & hidden in images. Barcodes may be scan by optical scanners known as barcode readers or looked from either an image by favorite software package. Barcodes come widely wont to implement Auto ID Data Capture (AIDC) systems that improve the speed & accuracy of computer data entry.

History

A idea for the barcode was developed by Norman Joseph Woodland and Bernard Silver[http://inventors.about.com/library/inventors/blbar_code.htm]. Around 1948 while graduate students at Drexel University, they developed a idea fallowing hearing a president of a food sales company wishing to become suspire to automate the checkout run. One of their number 1 ideas was to utilize Morse code printed out & extended vertically, producing narrow and wide blocks. Late, it switched to utilizing the "bulls-eye" nature and severity barcode using concentrical stripes. Them filed U.S patent [http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=2,612,994.WKU.&OS=PN/2,612,994&RS=PN/2,612,994 2,612,994] in October 20, 1949 for "Classifying Apparatus and Method". A patent was issued in October 7, 1952.

A number 1 barcode reader was built by Timber (world health organization was an IBM employee at the period) & Silver inside 1952 and included the Five hundred watt light bulb and a photomultiplier vacuum tube made by RCA for movie sound tracks (which were printed optically on film). This device was does'nt super practical: a output attend an oscilloscope, and a D watt bulb about placed fire to the paper containing their number 1 sample barcode. It was non commercially produced. Around 1962 they sold the patent to Philco, which later sold it to RCA. A invention of the laser in 1960 allowed barcode readers to be mass produced good deal extra cheaply, & a development of the integrated circuit made decoding of the looked barcode practical. Silver died around 1963 at age 38 before anything may appear of the patent.

Within 1972, a Kroger store in Cincinnati experimented with applying the bull's-eye barcode reader, sustaining assist from either RCA. Alas, a bulls-eye barcodes were real life to smudge in the period of printing, & weren't super successful. Meanwhile, Forest at IBM was getting a linear barcode that was adopted in April 3, 1973 as Universal Product Code. In June 26, 1974, the 1st retail product (the X dozen of Wrigley's Juicy Fruit chewing gum) was sold using the barcode reader, at Marsh's supermarket within Troy, Ohio. (This dozen of gum is at present in the Smithsonian's National Museum of American History.)

Within 1992, Woodland was awarded a National Medal of Technology by President George H. W. Bush.

Around 2004, Nanosys Inc. produced nanobarcodes - nanowires consisting of alternating segments of Si and Ge₁₀Si_One-x.

Applications

Barcodes (& more computer readable tags rather RFID) are utilized wherever physical objects want to become tagged by having trading tools that is to exist as made by computers. Instead of typewriting strings of information into the terminal, a operator simply has to display the code to a barcode reader. It as swell act well within fully machine-controlled environments, like baggage routing at drome.

a information contained around a barcode varies by using the application. In the simplest instance, an number is utilized as an index in database where the complete trading tools is saved. A EAN-13 and UPC codes commonly incurred in retail articles act this way.

Around more instances a barcode holds a complete tools itself, by owning there are no want for an external database. This led to the development of barcode symbologies that could express to a higher degree decimal digits, ranging from either in addition encoding just the capitals alphabet to the complete ASCII character set & beyond. A cause to encode ever supplementary facts within combination by owning a space requirements of elementary barcodes led to the development of matrix codes (a nature and severity of Second barcode), which don't consist of blocks however like the grid of square cells. Stacked barcodes come the compromise between admittedly Second barcodes & linear codes, & are formed by ingesting the traditional linear symbology & placing it around an envelope that allows multiple rows.

Symbologies

the mapping between messages & barcodes is known as a symbology. the specification of a symbology includes a encryption of a only digits/characters of a message besides when a run & prevent markers into blocks & space, the size of the quietly zone needed to exist when prior to & when the barcode besides as the computation of a checksum.

Linear symbologies may be classified chiefly by ii properties: Continuous vs. distinct: Characters around continuous symbologies abut, by owning of these character ending sustaining the space & the next beginning using a bar, or even contrariwise. Characters inside distinct symbologies lead off & prevent by having blocks; a intercharacter space is ignored, when hanker when these are non wide plenty to look rather a code ceases. Two-width vs. numerous-width: Blocks & spaces inside both-width symbologies come wide or even narrow; how else wide the wide bar is exactly hwhen there come no significance when hanker when the symbology requirements for wide blocks are adhered to (commonly two to three days as wide than a narrow bar). Blocks & spaces inside numbers of-breadth symbologies come 100% multiples of a basic width known as the module; virtually all such codes apply little joe breadth of Unity, Two, Three & Four modules.

Well-stacked symbologies consist of the given linear symbology repeated vertically inside multiple.

There are the big kin2nd of Two-D symbologies. the usual come matrix codes, which feature square or even dot-shaped modules intended in a grid pattern. Two-2nd symbologies likewise are around the kind of more ocular formats. Aside from either rounSecond system, there are many Two-D symbologies which uses steganography by hiding an array of different-sized or -shaped modules in the user-specified image (e.g., DataGlyph).

Scanner/symbology interaction

Linear symbologies come optimized to exist as page through by the optical maser market scanner, which sweeps the beam of weak through the barcode around the straight line, reading a slice of the barcode weak-dark system.

Well-stacked symbologies come besides optimized for optical maser scanning, by owning a optical maser making multiple pass through a barcode.

Two-2nd symbologies might't exist when review by a optical maser as there exists often there are no sweep pattern that can encompass the entire symbol. It must become looked by the camera capture device.

Types of barcodes
Linear barcodes

Symbology	Cont/Disc	Two/Many	Uses
Plessey	Continuous	Two	Catalogs, store shelves, inventory
UPC	Continuous	Many	Northerly America retail
EAN-UCC	Continuous	Many	Worldwide retail
Codabar	Discrete	Two	Libraries, blood banks, airbills
Interleaved 2 of 5	Continuous	Two	Sweeping, Libraries (NO)
Code 39	Discrete	Two	Various
Code 93	Continuous	Many	Various
Code 128	Continuous	Many	Various
Code 11	Discrete	Two	Telephones
Pharmacode	Neither	Two	Pharmaceutical Packaging
POSTNET	Continuous	Tall/short	Post office
PostBar	Discrete	Many	Post office
CPC Binary	Discrete	Two	Post office
Telepen	Continuous	Two	Libraries, etc (UK)

Stacked barcodes

Symbology	Notes
Codablock	Stacked 1D barcodes.
Code 16K	According to 1D Code 128.
Code 49	Stacked 1D barcodes from either Intermec Corp.
PDF417	The most common 2nd barcode. Public domain.
Micro PDF417

2-D barcodes

Symbology	Notes
3-DI	Developed by Lynn Ltd.
Adobe LiveCycle	From Adobe Systems.
ArrayTag	From either ArrayTech Systems.
Aztec Code	From Welch Allyn (now Hand Held Products). Public domain.
Small Aztec Code
Bullseye	This was the barcode tested around the Kroger store inside Cincinnati. It used concentrical blocks.
Code 1	Public domain.
CP Code	From CP Tron, Inc.
[http://www.parc.com/research/projects/dataglyphs/ DataGlyphs]	From either Xerox PARC.
Datamatrix	From RVSI Acuity CiMatrix. Nowadays Public Domain
Datastrip Code	From Datastrip, Inc.
Dot Code A
HueCode	From Robot Project Associates. Utilizes greyscale or even colour.
INTACTA.CODE	From INTACTA Technologies, Inc.
MaxiCode	Used by United Parcel Service. Nowadays Public Domain
MiniCode	From either Omniplanar, Inc.
PDF417	Originated by Symbol Technologies Public Domain.
QR Code	From Nippondenso ID Systems. Public domain.
SmartCode	From InfoImaging Technologies.
Snowflake Code	From Marconi Data Systems, Inc.
SpotCode	Circular code from High Energy Magic Ltd.
SuperCode	Public domain.
UltraCode	Black-and-white & colour versions. Public domain.
VeriCode, VSCode	From Veritec, Inc.