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]] A barcode (also '''bar code''') is a Machine-readable representation of information (usually dark ink on a light background to create high and low reflectance which is converted to 1s and 0s). Originally, barcodes stored data in the widths and spacings of printed parallel lines, but today they also come in patterns of dots, concentric circles, and text codes hidden within images. Barcodes can be read by Optical Scanner s called Barcode Reader s or scanned from an image by special software. Barcodes are widely used to implement Auto ID Data Capture (AIDC) systems that improve the speed and accuracy of Computer Data Entry . An advantage over other methods of AIDC is that it is less expensive to implement. It will cost about US$0.005 to implement a barcode compared to passive RFID which still costs about US$0.07 to US$0.30 per tag. Some Hot North American RFID Applications , RFID Radio HISTORY The first barcode was developed in 1948 by three graduate students at Drexel Institute of Technology, Jordin Johanson , Bernard Silver and Norman Joseph Woodland . They filed for a U.S. patent in October 1949 and it was granted in 1952. Its implementation was made possible through the work of Raymond Alexander and Frank Stietz, two engineers with Sylvania , as a result of their work on a system to identify railroad cars (who were also granted a patent). It was not until 1966 that barcodes were put to commercial use and they were not commercially successful until the 1980s. {Link without Title} While traditionally barcode encoding schemes represented only numbers, newer symbologies add new characters such as the uppercase alphabet to the complete ASCII character set and beyond. The drive to encode more information in combination with the space requirements of simple barcodes led to the development of matrix codes (a type of 2D barcode), which do not consist of bars but rather a grid of square cells. ''' Stacked Barcode s''' are a compromise between true 2D barcodes and linear codes, and are formed by taking a traditional linear symbology and placing it in an envelope that allows multiple rows. In 1970–71 IBM had three different barcodes that were alpha-numeric, Delta A, Delta B and Delta C, all self clocking delta distance codes. Two of these were developed to solve the needs of the National Retail Merchants Association or NRMA. Only the Delta B code was proposed to NRMA. The Delta C code, reduced to a numeric alphabet, was used for the UPC Label . The Delta C alpha-numeric code achieved twenty-one characters per inch with a reasonable retail label printer as compared to seven for Delta A and five for Delta B. USE Since their invention in the 20th century, barcodes — especially the UPC code — have slowly become an essential part of modern civilization. Their use is widespread, and the technology behind barcodes is constantly improving. Some modern applications of barcodes include:
THE UNIVERSAL PRODUCT CODE (COLLOQUIALLY, "UPC CODE") See Also: Universal Product Code The best-known and most widespread use of barcodes has been on consumer products. The UPC symbol is a response to a business need first identified by the US grocery industry in the early 1970s. Believing that automating the grocery checkout process could reduce labor costs, improve inventory control, speed up the process, and improve customer service, six industry associations, representing both product manufacturers and supermarkets, created an industry wide committee of industry leaders. Their two-year effort resulted in the announcement of the Universal Product Code and the U.P.C. barcode symbol on April 1 , 1973 . The UPC Symbol that was chosen by the committee was a modified version of a symbol design that was submitted by IBM . IBM also designed five versions of the UPC symbology for future industry requirements — UPC A, B, C, D, and E. 1 The U.P.C. made its first commercial appearance at the Marsh Supermarket in Troy, Ohio in June 1974.2 Legend has it that the first item with a barcode was a pack of Wrigley's gum. This isn't quite true. The first item scanned in a retail establishment was at 8:01 a.m. on June 26 , 1974 , and was a 10-pack of Juicy Fruit chewing gum. 3 The entire shopping cart also had barcoded items in it, but the gum was merely the first one picked up by the cashier. Originally, the modern day bar code was developed to identify railroad cars. However, a toll bridge in New Jersey requested that a similar system be developed so that it could quickly scan for cars that had paid for a monthly pass. Then the U.S. Post Office requested that a similar system be developed so that it could keep track of which trucks had entered the yard and when. These applications required special retroreflective labels. Finally, KalKan dog food asked the Sylvania team to develop a simpler (and cheaper) version which they could put on cases of dog food for inventory control. This, in turn, led to the grocery industry's interest. 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 there were those who 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 looked unpromising for the first couple of years, with Business Week eulogizing "The Supermarket Scanner That Failed." Working at Research Triangle Park, NC, in 1971 through 1972; three IBM engineers, Heard Baumeister , Bill Crouse , and George Laurer ; created the Universal Product Code Label. Development of the IBM UPC proposal See Also: Universal Product Code#Development_of_the_IBM_UPC_proposal l1=Universal Product Code, section Development of the IBM UPC proposal Joseph E. Fernandes proposed the use of the american UPC code for international inquiries. SYMBOLOGIES 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 . Linear symbologies can be classified mainly by two properties:
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 consist of a given linear symbology repeated vertically in multiple. There is a large variety of 2-D symbologies. The most common are matrix codes, which feature square or dot-shaped modules arranged on a grid pattern. 2-D symbologies 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 a user-specified image (for example, DataGlyph). Scanner/symbology interaction 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 bar code light-dark patterns. In the 1990s development of CCD imagers to read bar codes was pioneered by Welch Allyn. Imaging does not require moving parts, like a laser scanner does. In 2007, linear imaging is surpassing laser scanning as the preferred scan engine for its performance and durability. 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 a camera capture device. Scanners (barcode readers) See Also: 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. A later design, the "laser scanner," uses a Polygonal Mirror or Galvanometer -mounted mirror to scan a laser across the barcode — initially only in a straight line, but eventually in complicated patterns so the reader could read barcodes at any angle. In the 1990s some Barcode Reader manufacturers began working with Digital Camera s to capture barcodes, both linear and 2D. That technology has matured and now often surpasses laser scanners in performance and reliability. More recently, off-the-shelf digital cameras now have enough resolution to capture both 1D and 2D barcodes. Increasingly companies are looking to incorporate barcode scanning software into cameraphones. However, the camera phone optics are not well suited for standard codes that were designed for industrial dedicated scanners. As a result, new codes are being designed for mobile use such as Color Code and MCode . Verifier (Pika inspection) Barcode verifiers are primarily used by businesses that print barcodes, but any trading partner in the supply chain could test barcode quality. It is important to "grade" a barcode to ensure that any scanner in the supply chain can read the barcode. Retailers levy large fines and penalties for non-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 is given 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 acceptable grade. Barcode Verifier Standards
Barcode Verifier Manufacturers (partial list)
BENEFITS OF USING BARCODES 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 be made much more quickly and with more confidence. For example:
Besides sales and inventory tracking, barcodes are very useful in shipping/receiving/tracking.
The reason bar codes are business friendly is that bar code scanners are relatively low costing and extremely accurate – only about 1/100,000 entries will be wrong. TYPES OF BARCODES Linear barcodes Stacked barcodes 2D barcodes a.k.a. 2D codes A matrix code, also known as a '''2D barcode''' or simply a '''2D code''', is a two-dimensional way of representing information. It is similar to a linear (1-dimensional) barcode, but has more data representation capability. HOW ARE BAR CODES MADE? Machines (printers) print bar codes. People or computer programs tell the printer what to print based on the rules of the code and the data desired. The rules are generated by a person based on his/her ability to invent them, hopefully, but not always, based on printer tolerance and wand or scanner accuracy’s. Machines (wands or scanners) then read the barcode, hopefully based on the rules used to invent the code. This last step can easily be ignored, due to poor documentation, lost history or bad intuition, resulting in read failure. Intuition alone does not work with bar codes because machines do not “see” or “think” like people. The obvious failed in 1970 when the inferior Delta B code was invented as an improvement over the superior Delta A code. SEE ALSO
REFERENCES FURTHER READING
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