Barcode
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A barcode (also bar code) is a machine-readable (uses dark ink on white substrate to create high and low reflectance which is converted to 1's and 0's) representation of information in a visual format on a surface. 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 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.
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, 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. [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, 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 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:
- 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 profited 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.
- Rental car companies keep track of their cars by means of barcodes on the car's glass or bumper.
- Airlines track passenger luggage with barcodes, reducing the chance of loss.
- Recently, researchers have placed tiny barcodes on individual bees to track the insects' mating habits.
- The movement of nuclear waste can be tracked easily with a bar-code inventory system.
- In the late 1990s in Tokyo, there was a fad for temporary barcode shaped tattoos among high school girls.
The Universal Product Code (colloquially, "UPC Code")
The best-known and most widespread use of barcodes has been on consumer products. The Universal Product Code, or UPC., is unique because it was developed by the user community. Many technological innovations are first invented and then a need is found for the invention. The UPC 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 U.P.C. made its first commercial appearance in Marsh's Supermarket in Troy, Ohio in June 1974.[1]
Legend has it that the first item with a barcode was a pack of Wrigley's gum. This isn't quite true. The gum was the first item scanned in a retail establishment although the entire shopping cart also had barcoded items in it. The gum was merely the first one picked up by the cashier.[citation needed]
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."[1]
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 are 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)
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 cameras to capture barcodes, both linear and 2D. That technology has since been perfected 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[citation needed].
Verifier (Pika inspection)
Bar code verifiers are primarily used by businesses that print bar codes, but all trading partners in the supply chain will test bar code quality. It is important to "grade" a bar code to ensure that any scanner in the supply chain can read the bar code. Retailers levy large fines and penalties for non-compliant bar codes.
Bar code verifiers work in a similar way that a scanner works but instead of simple decoding a bar code, a verifier will perform a series of 8 tests. Each test is given a grade 0.0 - 4.0 (F-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.
Bar Code Verifier Standards
- The original US bar code quality specification was ANSI X3.182. UPC Codes use in the US ANSI/UCC5.
- The current international bar code quality specification is ISO/IEC 15416 (linear bar codes) and ISO/IEC 15415 (2D bar codes)
- The European Standard EN 1635 has been withdrawn and replaced by ISO/IEC 15416
- Bar code verifiers should comply with the ISO 15426-1 (linear bar code verifier compliance standard) or ISO 15426-2 (2d bar code verifier compliance standard)
Bar code verifier manufacturers:
- RJS/Printronix (linear)
- Hand Held Products (linear)
- Webscan (linear and 2D)
- Auto ID Solutions (2D)
- Stratix (linear)
- Axicon (linear)
- REA Elektronik GmbH (linear)
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.
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 assinged 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 shippment 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 costing and extremely accurate – only about 1/100,000 entries will be wrong.
Types of barcodes
Linear barcodes
| Symbology | Cont/Disc | Two/Many | Uses |
|---|---|---|---|
| Plessey | Continuous | Two | Catalogs, store shelves, inventory |
| U.P.C. | Continuous | Many | Worldwide retail, GS1 approved |
| Codabar | Discrete | Two | Old format used in libraries, blood banks, airbills |
| Code 25 - Non-interleaved 2 of 5 | Continuous | Two | Industrial (NO) |
| Code 25 - Interleaved 2 of 5 | Continuous | Two | Wholesale, Libraries (NO) |
| Code 39 | Discrete | Two | Various |
| Code 93 | Continuous | Many | Various |
| Code 128 | Continuous | Many | Various |
| Code 128A | Continuous | Many | Various |
| Code 128B | Continuous | Many | Various |
| Code 128C | Continuous | Many | Various |
| Code 11 | Discrete | Two | Telephones |
| CPC Binary | Discrete | Two | Post office |
| DUN 14 | Continuous | Many | Various |
| EAN 2 | Many | Addon code (Magazines), GS1 approved | |
| EAN 5 | Continuous | Many | Addon code (Books), GS1 approved |
| EAN 8, EAN 13 | Continuous | Many | Worldwide retail, GS1 approved |
| GS1-128 (formerly known as UCC/EAN-128), incorrectly referenced as EAN 128 and UCC 128 | Continuous | Many | Various, GS1 approved |
| GS1 DataBar formerly Reduced Space Symbology (RSS) | Continuous | Many | Various, GS1 approved |
| ITF-14 | Continuous | Many | Non-retail packaging levels, GS1 approved |
| Latent image barcode | Neither | Tall/short | Color print film |
| Pharmacode | Neither | Two | Pharmaceutical Packaging |
| PLANET | Continuous | Tall/short | United States Postal Service |
| POSTNET | Continuous | Tall/short | United States Postal Service |
| OneCode | Continuous | Tall/short | United States Postal Service, replaces POSTNET and PLANET symbols |
| MSI | Continuous | Two | Used for warehouse shelves and inventory |
| PostBar | Discrete | Many | Post office |
| RM4SCC | Continuous | Tall/short | Royal Mail |
| Telepen | Continuous | Two | Libraries, etc (UK) |
Stacked barcodes
| Symbology | Notes |
|---|---|
| Codablock | Stacked 1D barcodes. Base coding 199 |
| Code 16K | Based on 1D Code 128. |
| Code 49 | Stacked 1D barcodes from Intermec Corp. |
| PDF417 | The most common 2D barcode. Public domain. |
| Micro PDF417 |
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.
| Symbology | Notes |
|---|---|
| 3-DI | Developed by Lynn Ltd. |
| ArrayTag | From ArrayTech Systems. |
| Aztec Code | Designed by Andrew Longacre at Welch Allyn (now Hand Held Products). Public domain. |
| Small Aztec Code | Space-saving version of Aztec code. |
| Bullseye | The barcode tested in a Kroger store in Cincinnati. It used concentric bars. |
| Codablock | Stacked 1D barcodes. |
| Code 1 | Public domain. |
| Code 16K | Based on 1D Code 128. |
| Code 49 | Stacked 1D barcodes from Intermec Corp. |
| Color code | Mainly used for cell phones in Korea. |
| CP Code | From CP Tron, Inc. |
| Datamatrix | From RVSI Acuity CiMatrix/Siemens. Now Public Domain. |
| Datastrip Code | From Datastrip, Inc. |
| Dot Code A | Designed for the unique identification of items. |
| High Capacity Color Barcode | Developed by Microsoft; licensed by ISAN-IA. |
| HueCode | From Robot Design Associates. Uses greyscale or colour. |
| INTACTA.CODE | From INTACTA Technologies, Inc. |
| InterCode | From Iconlab, Inc. The standard 2D barcode in Korea. All 3 Korean mobile companies put the scanner program of this code into their handsets to access mobile internet, as a default embedded program. |
| MaxiCode | Used by United Parcel Service. Now Public Domain |
| mCode | Developed by Nextcode Corporation specifically for camera phone scanning applications. Designed to enable advanced cell mobile applications with standard camera phones. |
| MiniCode | From Omniplanar, Inc. |
| PDF417 | Originated by Symbol Technologies Public Domain. The most common 2D barcode. |
| Micro PDF417 | Facilitates codes too small to be used in PDF417. |
| PDMark | Developer by Ardaco. |
| PaperDisk | High density code -- used both for data heavy applications (10K-1 MB) and camera phones (50+ bits). Developed and patented by Cobblestone Software |
| QR Code | Developed, patented and owned by TOYOTA subsidiary Denso Wave initially for car parts management. Now public domain. Can encode Japanese Kanji and Kana characters, music, images, URLs, emails. De-facto standard for Japanese cell phones. |
| Semacode | A Data Matrix code used to encode URLs for applications using cellular phones with cameras. |
| SmartCode | From InfoImaging Technologies. |
| Snowflake Code | From Marconi Data Systems, Inc. |
| ShotCode | Circular barcodes for camera phones by OP3. Originally from High Energy Magic Ltd in name Spotcode. Before that probably know as TRIPCode. |
| SuperCode | Public domain. |
| UltraCode | Black-and-white & colour versions. Public domain. Invented by Jeffrey Kaufman and Clive Hohberger. |
| VeriCode, VSCode | From Veritec, Inc. |
| WaterCode | High-density 2D Barcode(440bytes/cm2) From MarkAny Inc. |
See also
- Automated identification and data capture (AIDC)
- Barcode printer
- Barcode scanner
- Global Trade Item Number
- Inventory control system
- ISBN
- RFID
- Semapedia
- Supply Chain Management
- Universal Product Code (UPC)
References
- ^ a b Varchaver, Nicholas (2004-05-31). "Scanning the Globe". Fortune. Retrieved 2006-11-27.
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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
- Datamatrix code, open-standard format; official site, by Acuity CiMatrix/Siemens
- Quick Response - QR code, open-standard format; official site, by Denso Wave
- Barcode at Curlie
- Free Barcode Software in the Public Domain
- Barcode Software
- Buy and Sell Used Barcode Equipment
- Openbarcodes
- Semapedia.org: connecting "the virtual and physical world by bringing the right information from the internet to the relevant place in physical space".