See also Radio-Frequency Identification (RFID)

"Wikipedia" encoded in Code 128

"Wikipedia" encoded in Code 93

"Wikipedia, the free encyclopedia" encoded in the DataMatrix 2D barcode

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 scanners called barcode readers 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.^[1]

History

The first barcode was developed in 1948 by two graduate students at Drexel Institute of Technology, 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 (who were also granted a patent), as a result of their work on a system to identify railroad cars. It was not until 1966 that barcodes were put to commercial use and they were not commercially successful until the 1980s. [1]

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 barcodes are a compromise between true 2D barcodes and linear codes (also known as 1D barcodes), and are formed by taking a traditional linear symbology and placing it in an envelope that allows multiple rows.

Use

Since their invention in the 20th century, barcodes — especially the UPC — 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:

• Practically every item purchased from a grocery store, department store, and mass merchandiser has a barcode on it. This greatly helps in keeping track of the large number of items in a store and also reduces instances of shoplifting (since shoplifters could no longer easily switch price tags from a lower-cost item to a higher-priced one). 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.
• 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.

The Universal Product Code (UPC)

Main article: 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. ^[2] The U.P.C. made its first commercial appearance at the Marsh Supermarket in Troy, Ohio in June 1974.^[3]

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. ^[2] 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 proclaiming "The Supermarket Scanner That Failed."^[3]

Development of the 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:

• 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 more wide 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 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, DataGlyphs).

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)

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.

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

• The original U.S. barcode quality specification was ANSI X3.182. UPC Codes used in the US ANSI/UCC5.
• The current international barcode quality specification is ISO/IEC 15416 (linear bar codes) and ISO/IEC 15415 (2D barcodes)
• The European Standard EN 1635 has been withdrawn and replaced by ISO/IEC 15416
• Barcode verifiers should comply with the ISO 15426-1 (linear barcode verifier compliance standard) or ISO 15426-2 (2d barcode verifier compliance standard)

Barcode Verifier Manufacturers (partial list)

• RJS/Printronix (linear)
• Hand Held Products (linear)
• Webscan (linear and 2D)
• Auto ID Solutions (2D)
• Stratix (linear)
• Axicon (linear)
• REA Elektronik GmbH (linear)

Barcode Verifier Test Code Manufacturers ((traceable reflectance and linear measure) used to check proper function of verifiers)

• Applied Image Inc. (Rochester, NY, USA)

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:

• 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 Indentifying 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 bar codes are business friendly is that bar code scanners are relatively low cost and extremely accurate – only about 1/100,000 entries will be wrong.

Types of barcodes

Linear barcodes

2D barcodes

Dolby Digital recording on 35 mm film (between the sprocket holes). Look very closely and you will see the Dolby "Double-D" logo in the middle of the code pattern. Dolby digital film audio is but one use of 2D barcodes.

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.

See also

• Automated identification and data capture (AIDC)
• Barcode printer
• Barcode scanner
• Data Matrix
• Global Trade Item Number
• Inventory control system
• ISBN
• Physical World Hyperlinks
• RFID
• Semacode
• Semapedia
• Sms barcode
• Supply Chain Management
• Universal Product Code (UPC)

References

1. ^ Some Hot North American RFID Applications, RFID Radio
2. ^ ^{a b} Nelson, Benjamin (1997). "From Punched Cards To Bar Codes". 
3. ^ ^{a b} Varchaver, Nicholas (2004-05-31). "Scanning the Globe". Fortune. Retrieved on 2006-11-27. 

Further reading

• 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
• 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 Univ Press, ISBN 0-674-76720-9

External links

Wikimedia Commons has media related to:

Barcode

• Barcode at the Open Directory Project
• ANSI Health Industry Bar Code (HIBC) Supplier Labeling Standard
• 2d Code Two dimensional barcodes, news, views and analysis.
• Openbarcodes project (Fonts and generators for a range of different barcodes released under the GPL)

A typical barcode scanner.

A barcode reader (or barcode scanner) is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a photo conductor translating optical impulses into electrical ones. Additionally, nearly all barcode readers contain decoder circuitry analyzing the barcode's image data provided by the photo conductor and sending the barcode's content to the scanner's output port.

Types of barcode readers

Methods

Barcode Readers are usually offered from three lines of heritage:

• Handheld readers for semi-automatic reading: The operator need not write, but must at least position the Reader near the label
• Fix-mount readers for automatic reading: The reading is performed laterally passing the label over the reader. No operator is required, but the position of the code target must coincide with the imaging capability of the reader
• Reader gates for automatic scanning: The position of the code must be just under the gate for short time, enabling the scanner sweep to capture the code target successfully.

This leads to the segregation of in-line reading, semi-automatic reading and automatic scanning.

Types of technology

The reader types can be distinguished as follows:

• Pen type readers

Pen type readers consist of a light source and a photodiode that are placed next to each other in the tip of a pen or wand. To read a bar code, the tip of the pen moves across the bars in a steady motion. The photodiode measures the intensity of the light reflected back from the light source and generates a waveform that is used to measure the widths of the bars and spaces in the bar code. Dark bars in the bar code absorb light and white spaces reflect light so that the voltage waveform generated by the photo diode is a representation of the bar and space pattern in the bar code. This waveform is decoded by the scanner in a manner similar to the way Morse code dots and dashes are decoded.

• Laser scanners

Laser scanners work the same way as pen type readers except that they use a laser beam as the light source and typically employ either a reciprocating mirror or a rotating prism to scan the laser beam back and forth across the bar code. As with the pen type reader, a photodiode is used to measure the intensity of the light reflected back from the bar code. In both pen readers and laser scanners, the light emitted by the reader is tuned to a specific frequency and the photodiode is designed to detect only this same frequency light.

• CCD Readers

CCD readers (also referred to as LED scanner) use an array of hundreds of tiny light sensors lined up in a row in the head of the reader. Each sensor can be thought of as a single photodiode that measures the intensity of the light immediately in front of it. Each individual light sensor in the CCD reader is extremely small and because there are hundreds of sensors lined up in a row, a voltage pattern identical to the pattern in a bar code is generated in the reader by sequentially measuring the voltages across each sensor in the row. The important difference between a CCD reader and a pen or laser scanner is that the CCD reader is measuring emitted ambient light from the bar code whereas pen or laser scanners are measuring reflected light of a specific frequency originating from the scanner itself.

• Camera-Based Readers

2D imaging scanners are the fourth and newest type of bar code reader currently available. They use a small video camera to capture an image of a bar code. The reader then uses sophisticated digital image processing techniques to decode the bar code. Video cameras use the same CCD technology as in a CCD bar code reader except that instead of having a single row of sensors, a video camera has hundreds of rows of sensors arranged in a two dimensional array so that they can generate an image.

Housing Types

The reader packaging can be distinguished as follows:

• Handheld scanner : with a handle and typically a trigger button for switching on the light source.
• Pen scanner (or wand scanner) : a pen-shaped scanner that is swiped.
• Stationary scanner : wall- or table-mounted scanners that the barcode is passed under or beside. These are commonly found at the checkout counters of supermarkets and other retailers.
• Fixed position scanner : an industrial barcode reader used to identify products during manufacture or logistics. Most often used on conveyer tracks to identify cartons or pallets which need to be routed to another process or shipping location.
• PDA scanner : a PDA with a built-in barcode reader or attached barcode scanner e.g. Grabba.

Methods of networking

Wireless networking

Modern handheld barcode readers are operated in wireless networks according to IEEE 802.11g (WLAN) or IEEE 802.15.3 (Bluetooth). However, such configuration limits the time of operation from battery or rechargeable battery and required recharging at least after a shift of operation.

Types of connectors

PS/2 port.

Most barcode readers use a PS/2 or USB cable for output: PS/2 cables are connected to the host computer in a Y formation, the PS/2 keyboard port with its first end, to the keyboard with its second, and to the barcode reader with its third end. The barcode characters are then received by the host computer as if they came from its keyboard decoded and converted to keyboard input within the scanner housing. This makes it easy to interface the bar code reader to any application that is written to accept keyboard input.

Many readers can also be equipped with an RS-232 output port so that the decoded characters arrive at the computer via one of its RS-232 connectors. A program called a "Software Wedge" takes the data from the bar code reader and feed it to the application where the data has to go.

USB is supported by many newer scanners. In many cases a choice of USB interface types (HID, CDC) are provided.

There are a few other less common interfaces. Wand emulation is another output type that takes the raw wave and decodes it, normalizing the output so it can be easily decoded by the host device. Wand emulation can also convert symbologies that may not be recognized by the host device into another symbology (typically Code 39) that can be easily decoded.

Resolution

The scanner resolution is measured by the size of the dot of light emitted by the reader. If this dot of light is wider than any bar or space in the bar code, then it will overlap two elements (two spaces or two bars) and it may produce wrong output. On the other hand, if a too small dot of light is used, then it can misinterpret any spot on the bar code making the final output wrong.

The most commonly used dimension is 13 mils (0.3302 mm). As it is a very high resolution, it is extremely important to have bar codes created with a high resolution graphic application.

While cell phone cameras are not suitable for many traditional barcodes, there are 2D barcodes (such as Semacode) which are optimized for cell phones. These open up a number of applications for consumers:

• Movies: DVD/VHS movie catalogs
• Music: CD catalogs, play MP3 when scanned
• Book catalogs
• Groceries, nutrition information, making shopping lists when the last of an item is used, etc.
• Personal Property inventory (for insurance and other purposes)
• Calling cards: 2D barcodes can store contact information for importing.
• Brick and mortar shopping: Portable scanners can be used to record items of interest for looking up online at home.
• Coupon management: weeding expired coupons.
• Personal finance. Receipts can be tagged with a barcode label and the barcode scanned into personal finance software when entering. Later, scanned receipt images can then be automatically associated with the appropriate entries. Later, the bar codes can be used to rapidly weed out paper copies not required to be retained for tax or asset inventory purposes.
• If retailers put barcodes on receipts that allowed downloading an electronic copy or encoded the entire receipt in a 2D barcode, consumers could easily import data into personal finance, property inventory, and grocery management software. Receipts scanned on a scanner could be automatically identified and associated with the appropriate entries in finance and property inventory software.

External links

Electronics Portal

• Learn More About Barcode Input Devices
• Open Source Barcode Reader Driven Grocery List Software