A
barcode is an optical
machine-readablerepresentation of data. Originally, bar codes represented data in the widths (lines) and the spacings of parallel lines, and may be referred to as linear or 1D(1 dimensional) barcodes or symbologies. They also come in patterns of squares, dots, hexagons and other geometric patterns within images termed 2D (2dimensional) matrix codes or symbologies. Although 2D systems use symbols other than bars, they are generally referred to as barcodes as well.
The first use of barcodes was to label railroad cars, but they were not commercially successful until they were used to automate
supermarket checkout systems, a task in which they have become almost universal. Their use has spread to many other roles as well, tasks that aregenerically referred to as
Auto ID Data Capture (AIDC). Other systems are attempting to make inroads in the AIDC market, but thesimplicity, universality and low cost of barcodes has limited the role of these other systems. It costs about half a United States cent (US$0.005) to implementa barcode compared to passive
RFID which still costs about $0.07 to $0.30 pertag.[sup]
[1][/sup]
Barcodes can be read by
optical scanners called
barcode readers, or scanned from an image by special software. Scanningsoftware for 2D codes is built-in to or available for many mobile phones, and is especially popular in
Japan,
India &
Europe.
[h2]History[/h2]
In 1932 business student
Wallace Flint of
Harvard Business School wrote a thesis promoting an "automated grocery store" using
punch cards, which customers would hand to a clerk, who would load theminto a reader, causing flow racks to deliver the desired products, after which an itemized bill would automatically be produced.[sup]
[2][/sup] In spite of its promise, punch cardsystems were expensive, and the country was in the midst of the
GreatDepression, and the idea was never implemented.
In 1948
Bernard Silver (1924-62), a graduate student at
Drexel Institute of Technology in
Philadelphia, overheard the president of a local food chain asking one of thedeans to research a system to automatically read product information during checkout. Silver told his friends
Norman Joseph Woodland (1921-) and
JordinJohanson about the request, and the three started working on a variety of systems. Their first working system used
ultraviolet ink, but this proved to fade and was fairly expensive.[sup]
[2][/sup]
Convinced that the system was workable with further development, Woodland quit his position at Drexel, moved into his father's apartment in Florida, andcontinued working on the system. His next inspiration came from
Morse code, and heformed his first barcode from sand on the beach when "I just extended the dots and dashes downwards and made narrow lines and wide lines out ofthem."[sup]
[2][/sup] To read them, he adapted technology from
optical soundtracks in movies, using a 500-watt
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 aline, allowing it to be scanned in any direction.
On 20 October 1949 they 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 and Johanson moved to
IBM and continually tried to interest IBM in developing the system. The company eventuallycommissioned a report on the idea, which concluded that it was both feasible and interesting, but that processing the resulting information would requireequipment that was some time off in the future.
In 1952
Philco purchased their patent, and then sold it to
RCA the same year. In 1962 Silver died in a
car accident.
[h3]Collins at Sylvania[/h3]
During his undergraduate degree,
David Collins worked at the
Pennsylvania Railroad and became aware of the need to automatically identify
train cars. Immediately after receiving his master's degree from
MIT in 1959, he started work at
Sylvania and began addressing the problem. He developed asystem using blue and yellow reflective stripes attached to the side of the cars, encoding a six-digit company identifier and a four-digit car number. Lightreflected off the stripes was fed into one of two photomultipliers, filtered for blue or yellow.
The
Boston and Maine Railroadtested the system on their
gravel cars in 1961. The tests continued until 1967, when the
Association of American Railroads (AAR)selected it as a standard across the entire North American fleet. The installations began on October 10, 1967. However, the
economic downturn and rash of
bankruptcies in the industry in the early 1970s greatly slowed the rollout, and it wasn't until 1974 that 95% of the fleet was labeled. Toadd to its woes, the system was found to be easily fooled by dirt in certain applications, and the accuracy was greatly affected. The AAR abandoned the systemin the late 1970s, and it was not until the mid-1980s that they introduced a similar system, this time based on radio tags.
The railway project had proven to be a bust, but a
toll bridge in
New Jersey requested that a similar system be developed so that it could quickly scan for carsthat had paid for a monthly pass. Then the
U.S. PostOffice requested the development of a system to keep track of the trucks entering and leaving their facilities. These applications required special
retroreflective labels. Finally,
Kal Kan asked the Sylvania team to develop a simpler (and cheaper) version which they could put oncases of pet food for inventory control. This, in turn, led to the grocery industry's interest.
[h3]Computer Identics[/h3]
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 forother 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 Computer Identics. Computer Identics started working with
helium-neon lasers in place of light bulbs, scanning with a mirror to locate the barcode anywhere up toseveral feet in front of the scanner. This made the entire process much simpler and more reliable, as well as allowing it to deal with ripped codes by readingthe intact portions.
Computer Identics installed their first two systems in early 1969, one at a
General Motors factory in
Pontiac, Michigan, andanother at a distribution center at the
General Trading Company in
Carlstadt, New Jersey[sup][
citationneeded][/sup]. The General Motors system was used to identify car
axles in inventoryamong the 18 models produced at the factory.
[h3]UPC[/h3]
Main article:
Universal Product Code
In 1966 the
National Association of Food Chains (NAFC) held a meeting where they discussed the idea ofusing automated checkout systems.
RCA, having purchased rights to the original Woodland patent, hadattended the meeting and set up an internal project to develop a system based on the bullseye code. The
Kroger grocery chain volunteered to test it.
In mid-1970, the NAFC established the U.S. Supermarket Ad Hoc Committee on a Uniform Grocery Product Code, which set guidelines for barcode development andcreated a symbol selection subcommittee to help standardize the approach. In cooperation with consulting firm McKinsey & Co., they developed a standardized11-digit code to identify any product. The committee then sent out a contract tender to develop a 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]
[3][/sup] Awide variety of barcode approaches were studied, including linear codes, RCA's bullseye concentric circle code, systems with starburst patterns, and evenodder varieties.
In the spring of 1971 RCA demonstrated their bullseye code at another industry meeting, and IBM executives at the meeting noticed the crowds at the RCAbooth, immediately setting out to develop their own system. IBM marketing specialist Alec Jablonover remembered that the company still employed thesystem's inventor Woodland, and he was set up in new facilities in North Carolina to lead the development.
In July 1972 RCA began an eighteen-month test of their system in a Kroger store in Cincinnati. Barcodes were printed on small pieces of adhesive paper, andattached by hand by store employees when they were adding price tags. The code proved to have a serious problem. During printing, presses sometimes smear inkin 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 April 3, 1973 theIBM UPC code 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, andE [sup]
[4][/sup]
NCR installed a testbed system at Marsh's Supermarket in
Troy, Ohio, near thefactory that was producing the equipment. On June 26, 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 displayin the
Smithsonian Institution. It was the first commercialappearance of the UPC.[sup]
[5][/sup]
Economic studies conducted for the grocery industry committee projected over $40 million in savings to the industry from scanning by the mid-1970s. Thosenumbers were not achieved in that time frame and there were those who predicted the demise of barcode scanning. The usefulness of the barcode required theadoption of expensive scanners by a critical mass of retailers while manufacturers simultaneously adopted barcode labels. Neither wanted to move first andresults weren't promising for the first couple of years, with
Business Week proclaiming "The Supermarket Scanner That Failed."[sup]
[5][/sup]
For years many had worked to computerize the grocery industry. In 1971 IBM had assembled a team for an intensive planning session, day after day, 12 to 18hours a day, to hash out how the whole system might operate and to schedule a rollout plan. By 1973 they were meeting with grocery manufacturers to introducethe symbol that would need to be printed on all of their products. There were no cost savings for a grocery to use it unless at least 70% of the grocery'sproducts had the barcode printed on the product by the manufacturer. IBM was projecting that 75% would be in 1975. Even though that was achieved, there stillwere scanning machines in fewer than 200 grocery stores by 1977.[sup]
[6][/sup]
Experience with barcode scanning in those stores revealed benefits previously unappreciated. The detailed sales information acquired by the new systemsallowed far better servicing of customer needs. This was reflected in the fact that about 5 weeks after installing barcode scanners, sales in grocery storestypically started climbing and eventually leveled off at a 10-12% increase in sales that never dropped off. There also was a 1% to 2% decrease in operatingcost for the stores that enabled them to lower prices in order to increase market share. It was shown in the field that the return on investment for a barcodescanner was 41.5%. By 1980 the technology was being adopted by 8000 stores per year.[sup]
[6][/sup]
[h2]Industrial adoption[/h2]
In 1981 the
United States Departmentof Defense adopted the use of Code 39 for marking all products sold to the United States military. This system, LOGMARS, is still used by DoD and is widelyviewed as the catalyst for widespread adoption of barcoding in industrial applications.[sup]
[7][/sup]
[h2]Use[/h2]
Barcodes - especially the
UPC - have slowly become anessential part of modern civilization. Their use is widespread, and the technology behind barcodes is constantly improving. Some modern applications ofbarcodes include:
- Almost every item purchased from a grocery store, department store, and mass merchandiser has a UPC barcode on it. This greatly helps in keeping track of a large number of items in a store and also reduces instances of shoplifting involving price tag swapping, although shoplifters can now print their own barcodes. Since the adoption of barcodes, both consumers and retailers have benefited from the savings generated.
- Document Management tools often allow for barcoded sheets to facilitate the separation and indexing of documents that have been imaged in batch scanning applications.
- The tracking of item movement, including rental cars, airline luggage, nuclear waste, mail and parcels.
- Since 2005, airlines use an IATA-standard 2D barcode on boarding passes (BCBP), and since 2008 2D barcodes sent to mobile phones enable electronic boarding passes.[sup][8][/sup]
- Recently, researchers have placed tiny barcodes on individual bees to track the insects' mating habits.
- Many tickets now have barcodes that need to be validated before allowing the holder to enter sports arenas, cinemas, theatres, fairgrounds, transportation etc.
- Used on automobiles, can be located on front or back.
- Joined with in-motion checkweighers to identify the item being weighed in a conveyor line for data collection
- Some 2D barcodes embed a hyperlink to a web page. A capable cellphone might be used to read the barcode and browse the linked website.
- In the 1970s and 1980s, software source code was occasionally encoded in a barcode and printed on paper. Cauzin Softstrip and Paperbyte[sup][9][/sup] are barcode symbologies specifically designed for this application.
- The 1991 Barcode Battler computer game system, which used any standard barcode to generate combat statistics.
- 1992, Veterans Health Administration developed Bar Code Medication Administration system (BCMA).
- At the turn of the century, many artists started using barcodes in art, such as Scott Blake's Barcode Jesus.
[h2]Symbologies[/h2]
The mapping between messages and barcodes is called a
symbology. The specification of a symbology includes the encoding of the singledigits/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 thebarcode as well as the computation of a
checksum.
Linear symbologies can be classified mainly by two properties:
- 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; how wide a wide bar is exactly 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.
Some symbologies use
interleaving. The first character is encoded using blackbars 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 pairsover the same section of the barcode.
Interleaved 2 of 5 is an exampleof this.
Stacked symbologies consist of a given linear symbology repeated vertically in multiple.
There is a large variety of 2D symbologies. The most common are matrix codes, which feature square or dot-shaped modules arranged on a grid pattern. 2-Dsymbologies also come in a variety of other visual formats. Aside from circular patterns, there are several 2-D symbologies which employ
steganography by hiding an array of different-sized or -shaped modules within auser-specified image (for example,
DataGlyphs).
Linear symbologies are optimized to be read by a laser scanner, which sweeps a beam of light across the barcode in a straight line, reading a
slice of the barcode light-dark patterns. In the 1990s development of CCD imagers to read barcodes was pioneered by Welch Allyn. Imaging doesnot require moving parts, like a laser scanner does. In 2007, linear imaging was surpassing laser scanning as the preferred scan engine for its performance anddurability.
Stacked symbologies are also optimized for laser scanning, with the laser making multiple passes across the barcode.
2-D 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 animage-based scanner employing a
charge coupleddevice (CCD) or other digital camera sensor technology.
[h3]Scanners (barcode readers)[/h3]
Main article:
Barcode reader
The earliest, and still the cheapest, barcode scanners are built from a fixed light and a single
photosensor that is manually "scrubbed" across the barcode.
Barcode scanners can be classified into three categories based on their connection to the computer. The older type is the RS-232 barcode scanner. This typerequires special programming for transferring the input data to the application program. Another type connects between a computer and its PS/2 or AT keyboardby the use of an adaptor cable. The third type is the USB barcode scanner, which is a more modern and more easily installed device than the RS-232 scanner.Like the keyboard interface scanner, this has the advantage that it does not need any code or program for transferring input data to the application program;when you scan the barcode its data is sent to the computer as if it had been typed on the keyboard.
[h3]Verifier (Pika inspection)[/h3]
Barcode verifiers are primarily used by businesses that print barcodes, but any trading partner in the supply chain could test barcode quality. It isimportant to "grade" a barcode to ensure that any scanner in the supply chain can read the barcode. Retailers levy large fines and penalties fornon-compliant barcodes.
Barcode verifiers work in a way similar to a scanner but instead of simply decoding a barcode, a verifier performs a series of eight tests. Each test isgiven a grade from 0.0 to 4.0 (F to A) and the lowest of any of the tests is the scan grade. For most applications a 2.5 (C) grade is the minimum acceptablegrade.
Barcode verifier standards:
- Barcode verifiers should comply with the ISO 15426-1 (linear barcode verifier compliance standard) or ISO 15426-2 (2D barcode verifier compliance standard)
- The current international barcode quality specification is ISO/IEC 15416 (linear barcodes) and ISO/IEC 15415 (2D barcodes)
- 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. UPC Codes used in the US ANSI/UCC5.
Barcode verifier manufacturers (partial list):
- Auto ID Solutions (2D)
- LVS(R)Inc (linear, 2D)
- Intermec (linear, 2D)
- Motorola Symbol (linear, 2D)
- Axicon (linear, 2D)
- Code Corporation (linear, 2D)
- Cognex Corporation (2D, UID)
- Honeywell (earlier known as Metrologic and HHP) (linear, 2D)
- REA Elektronik GmbH (linear)
- RJS/Printronix (linear)
- Siemens (linear, 2D, UID)
- Microscan (linear, 2D, UID)
- Stratix (linear)
- Webscan (linear, 2D)
- Datalogic (linear, stacked, 2D, direct part marked)
Barcode verifier test code manufacturers:
- Applied Image Inc. (Rochester, NY)
[h2]Benefits[/h2]
In point-of-sale management, the use of barcodes can provide very detailed up-to-date information on key aspects of the business, enabling decisions to bemade much more quickly and with more confidence. For example:
- Fast-selling items can be identified quickly and automatically reordered to meet consumer demand,
- Slow-selling items can be identified, preventing a build-up of unwanted stock,
- The effects of repositioning a given product within a store 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.
Besides sales and inventory tracking, barcodes are very useful in shipping/receiving/tracking.
- When a manufacturer packs a box with any given item, a Unique Identifying Number (UID) can be assigned to the box.
- A relational database can be created to relate the UID to relevant information about the box; such as order number, items packed, qty packed, final 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.
- Tracking results when shipments are sent to a Distribution Center (DC) before being forwarded to the final destination.
- When the shipment gets to the final destination, the UID gets scanned, and the store knows where the order came from, what's inside the box, and how much to pay the manufacturer.
The reason barcodes are business-friendly is that the scanners are relatively low cost and extremely accurate compared to key-entry, with only about 1substitution error in 15,000 to 36 trillion characters entered.[sup]
[1![Alien 0] 0]](/styles/default/xenforo/NTemojis/alien.gif)
[/sup] The exact error rate depends on the type of barcode.