Bar codes Presentation · 2015-02-19 · Barcodes – The 1 st type were 1D codes – Correct name for these is Universal Product Code (UPC) – They are numeric only. – Its most

Malling U3A Advanced Computer Group

Bar Codes

Chris Daly – 17th February 2015

Barcodes� What are Barcodes ?

� “A barcode is an optical machine-readable representation of data relating to the object to which it is attached.”

� Originally barcodes systematically represented data by varying the widths and spacings of parallel lines, and may be referred to as linear or one-dimensional (1D).

� Later they evolved into rectangles, dots, hexagons and other geometric patterns in two dimensions (2D).

� Although 2D systems use a variety of symbols, they are generally referred to as barcodes as well.

� Barcodes originally were scanned by special optical scanners called barcode readers.

� Later, scanners and interpretive software became available on devices including desktop printers and smartphones

Barcodes

– The 1st type were 1D codes

– Correct name for these is

Universal Product Code (UPC)

– They are numeric only.

– Its most common form, the UPC-A, consists of 12 numerical digits, which are uniquely assigned to each trade item. Along with the related EAN barcode, the UPC is the barcode mainly used for scanning of trade items at the point of sale, per GS1 specifications.

Barcodes– The latest type are 2D codes

– Correct name for these is

Quick Response Code(QR code)

– These are alphanumeric.

– QR codes consist of black modules (square dots) arranged in a square grid on a white background, which can be read by an imaging device (such as a camera) and processed using Reed–Solomon error correction until the image can be appropriately interpreted.

UPC Barcodes - History� In 1948 N J Woodland and B Silver in the USA started developing a system to automatically read product information during supermarket checkout.

� The first system used ultraviolet inks, but they faded & were expensive.

� Woodland's next idea was inspired by morse code.

� He formed his first barcode from sand on the beach. "I just extended the dots and dashes downwards and made narrow lines and wide lines out of them”

� They adapted technology from soundtracks in movies to read them.

� It was later decided that the system would work better if it were printed as a circle instead of a line, allowing it to be scanned in any direction.

UPC Barcodes - History

� On 20 October 1949 Woodland and Silver 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.

� Patent issued on 7th October 1952.

� Woodland moved to IBM and tried to interest them in the idea.

� IBM offered to buy patent, but offer too low, and sold to Philco in 1962, then eventually sold to RCA.

UPC Barcodes - History� Early use of a type of barcode in industry was sponsored by the Association of American Railroads in the late 1960s.

� Work was done by D Collins at GTE Sylvania.

� Called KarTrak ACI (Automatic Car Identification), this scheme involved placing coloured stripes in various combinations on steel plates which were affixed to the sides of railroad rolling stock.

� Two plates were used per car, one on each side, with the arrangement of the coloured stripes representing things such as ownership, type of equipment, and identification number.

� The plates were "read" by a trackside scanner located at the entrance to a classification yard, while the car was moving past.

� The project was abandoned after about ten years because the system proved unreliable after long-term use in the field.

UPC Barcodes - History� The railway project had failed, but a toll bridge in New Jersey requested a similar system so that it could quickly scan for cars that had purchased a monthly pass.

� Then the U.S. Post Office requested a system to track trucks entering and leaving their facilities.

� These applications required special retroreflector (a device or surface that reflects light back to its source with a minimum of

scattering) labels.

� Finally, Kal Kan asked the Sylvania team for a simpler (and cheaper) version which they could put on cases of pet food for inventory control.

� Collins then quit Sylvania and formed Computer Identics Corporation. (CIC)

UPC Barcodes - History� CIC started working with helium–neon lasers in place of bulbs.

� Scanning was with a mirror to locate the barcode anywhere up to several feet in front of the scanner.

� This made the entire process much simpler and more reliable, as well as allowing it to deal with damaged labels.

� CIC installed one of its first two scanning systems in 1969 at a General Motors (Buick) factory in Flint, Michigan.

� The system was used to identify a dozen types of transmissions moving on an overhead conveyor.

� The other system was installed at General Trading Company's distribution centre in Carlstadt, New Jersey to direct shipments to the proper loading bay.

UPC Barcodes - History� In 1966 the National Association of Food Chains (NAFC) held a meeting to discuss the idea of automated checkout systems.

� RCA attended the meeting and initiated an internal project to develop a system based on the bullseye code.

� The Kroger grocery chain volunteered to test it.

� The NAFC developed a standardized 11-digit code to identify any product.

� 1971 RCA demonstrated their bullseye code at another industry meeting. IBM executives at the meeting noticed the crowds at the RCA booth and immediately developed their own system.

UPC Barcodes - History� In July 1972 RCA began an eighteen-month test in a Kroger store in Cincinnati, using bullseye codes.

� The code proved to have a serious problem. During printing, presses sometimes smear ink in 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.

� On 3 April 1973 the IBM UPC was selected by NAFC as their standard. IBM had designed five versions of the UPC for future industry requirements: UPC A, B, C, D, and E.

UPC Barcodes - History� The very first scanning of the UPC barcode was on a pack of

Wrigley Company chewing gum on 26th June 1974.

� There were no cost savings for a grocery to use it unless at least 70% of the grocery's products had the barcode printed on the product by the manufacturer.

� IBM was projecting that 75% would be needed in 1975.

� Even though that was achieved, there were still scanning machines in fewer than 200 grocery stores by 1977.

� It was shown in the field that the return on investment for a barcode scanner was 41.5%.

� By 1980, 8,000 stores per year were converting.

UPC Barcodes - History

� In 1981, the United States Department of Defence adopted the use of Code 39 (An alphanumeric system) for marking all products sold to the United States military.

� This system, Logistics Applications of Automated Marking and Reading Symbols (LOGMARS), is still used by DoD and is widely viewed as the catalyst for widespread adoption of barcoding in industrial uses.

1D Barcodes - Structure� All barcodes are constructed from a series of bars and intervening spaces.

� The relative size of these bars and spaces and the number of them is decided by the specification for the symbology (or bar code type) which is being used.

� There are a number of symbologies in common use.

� Each symbology differs in the way data is encoded and often also in the type or amount of data.

� Generally speaking, only one symbology is chosen for a

particular application.

1D Barcodes - Structure

There are

numerous

UPC barcode

standards

1D Barcodes - Structure

� Those involved in bar coding should understand the relationship between the Bar Code Symbology and it's Application Specification.

� Symbology is not specific to a particular application or numbering system. It is simply the rules that govern the construction of the bar code and its operational limits.

� The Application Specification adopts a particular symbology and defines how articles will be numbered.

1D Barcodes - Structure� A few of the official bodies and the areas they administer :-

(a) GS1(Associations in most countries)

� EAN 8 & 13 for retail items

� Interleaved 2 of 5 (ITF) for outer cases

� Code 128 for supplementary coding

(a) The Publishers Association

� ISBN coding for books

(a) The British Library/Periodicals Barcoding Association

� ISSN coding for magazines and periodicals

(a) Uniform Code Council USA

� UPC coding for retail items in the U.S. and Canada

1D Barcodes - Structure

� There are misconceptions about the information a bar code contains.

� People are familiar with the use of bar codes in retail stores and assume that the bar code contains the price of the item.

� The bar code will carry only the unique number which identifies that item.

� At the supermarket check-out the number is read by the scanner and the price extracted from a "look-up" table on the stores main computer.

1D Barcodes - Symbology

� Most bar code symbologies have certain common features:-

� Human Readable Characters

� In almost all cases all of the useful information is printed in "human-readable" form, usually at the base of the code

� Light Margins

� All bar code types require a certain amount of light space to the left and right of the bar code. This enables the scanner to differentiate between the bar code and

surrounding graphics.

1D Barcodes - Symbology

� Start and Stop Characters

� It is usual for a symbology to have a start and stop pattern at each end of the bar code symbol.

� This special bar/space arrangement may simply tell the scanner that the read was complete.

� A start and stop pattern may also indicate the orientation of the bar code.

� By having a differing pattern on the left from the right the scanner can detect if the code was read upside-down.

1D Barcodes - Symbology� Bar Code Dimensions

� The method of describing bar code size varies between symbologies.

� Code types such as UPC and EAN use a magnification factor based around the standard size (100% magnification).

� Many symbol types are modular, that is the width of all bars and spaces are derived from the narrow bar (or X dimension). In such codes the wide bars and spaces are constructed from 2, 3 or more narrow bars according to the rules which apply.

1D Barcodes - Symbology� In UPC-A barcodes each digit is represented by a unique pattern of two bars and two spaces.

� The bars and spaces are variable width:-

� They may be one, two, three, or four modules wide.

� The total width for a digit is always seven modules.

� To represent the 12 digits of the UPC-A code requires a total of 7×12 = 84 modules

� A complete UPC-A includes 95 modules: the 84 modules for the digits (L and R) combined with 11 modules for the start, middle, and end (S, M, and E) patterns

� UPC-A and UPC-E each provide a theoretical maximum of 1 trillion (10^12) unique barcodes.

1D Barcodes - SymbologyHow each number is represented in UPC-A

1D Barcodes - Symbology� Left-side digits have odd parity, which means the total width of the black bars is an odd number of modules & right-hand side digits have even parity.

� Consequently, a UPC scanner can determine whether it is scanning a symbol from left-to-right or from right-to-left (the symbol is upside-down).

� After seeing a start or end pattern (they are the same bar-space-bar whichever way they are read), an upside-down symbol will not confuse the scanner.

� Also the right-hand digits are the optical complement of the left-hand digits. A number on the left side of the UPC will be made up of black bars and white spaces, the same number on the right side would be made up of white bars and black spaces.

1D Barcodes - ApplicationIn its standard version (UPC-A), the bar code consists of a 5 digit manufacturer number and a 5 digit product number. In addition there is a 1 digit number system identifier at the start of the code. This number system digit denotes the use of one of ten number systems defined by UPC:

� 0, 6 and 7 are for regular UPC codes.

� 2 is for random weight items, e.g. meat, marked in-store.

� 3 is for National Drug Code & National Health Related items

� 4 is for in-store marking of non-food items.

� 5 is for coupon use.

� 1,8 and 9 are not used at present.

� The UPC symbol also has a check digit which is the last digit of the code and is calculated according to the algorithm used for EAN.

1D Barcodes - Application

QR Barcodes - History� The QR code system was invented in 1994 by Denso Wave in Japan and they hold the patent, but allow free use.

� The word QR code is a trademark of Denso Wave Inc.

� The purpose of the code was to track vehicles during manufacture.

� Although initially used for tracking parts in vehicle manufacturing, QR codes are used both in commercial tracking applications and convenience-oriented applications aimed at mobile-phone users.

� QR codes are now used in a large variety of applications.

QR Barcodes - Use� In its simplest sense think "print based hypertext link".

� Simply encode a URL into the QR Code and point a mobile phone (or other camera-enabled mobile) at it.

� If the device has had QR Code decoding software installed on it, it will fire up its browser and go straight to that URL.

� A QR Code can also contain a phone number, an SMS message, V-Card data or just plain alphanumeric text.

� The scanning device will respond by opening up the correct application to handle the encoded data.

� QR codes storing addresses and URLs may appear in magazines, on signs, on buses, on business cards, or on almost any object about which users might want information.

QR Barcodes - Use� QR codes also may be linked to a location to track where a code has been scanned.

� Either the application that scans the QR code retrieves the geo information by using GPS and cell tower triangulation (aGPS) or the URL encoded in the QR code itself is associated with a location.

� Recruiters have started placing QR codes in job advertisements, while applicants have started sporting it in their CVs and visiting cards.

� You can generate and print your own QR codes for others to scan and use by visiting one of several pay or free QR code-generating sites or apps. (http://www.qrstuff.com)

QR Barcodes - Structure� The technical specifications for a QR Code are set down in the ISO-18004 standard so they are the same all over the world.

� The only significant variations from one QR code to another (apart from the data it contains) is the number of modules required to store the data.

� Version 1 QR Code is a 21x21 array of data elements with the array increasing in size by 4 modules for each increase in version number.

� The largest standard QR Code is a Version 40 symbol of 177x177 modules in size and can hold up 4296 characters of alphanumeric data (theoretically) compared to 25 characters for a Version 1 QR Code.

QR Barcodes - Structure

QR Barcodes - Structure� The resolution of average present-day camera-enabled portable devices is such that the size of the data modules (dots) on a QR Code of Version 5 or above (37x37) presents a real risk of incorrect decoding of the symbol by the device.

� When creating a QR Code intended for use with mobile phones it's best to stick to Version 4 or lower.

� Also a QR Code symbol of at least 2cm (0.85inches) across.

� The QR Code also contains its own error correction data, internal orientation calibration, and self-alignment markers.

� In this way it doesn't matter whether the QR code is upside down or wrapped around a curved surface, the message will still get through.

QR Barcodes - StructureThe image processor locates the three distinctive squares at the corners of the QR code image, using a smaller square (or multiple squares) near the fourth corner to normalize the image for size, orientation, and angle of viewing. The small dots throughout the QR code are then converted to binary numbers and validated with

an error-correcting code.

QR Barcodes - Structure� The format information records two things: the error correction level and the mask pattern used for the symbol.

� Masking is used to break up patterns in the data area that might confuse a scanner, such as large blank areas or misleading features that look like the locator marks.

� The mask patterns are defined on a grid that is repeated as necessary to cover the whole symbol.

� The message dataset is placed from right to left in a zigzag pattern.

� In larger symbols, this is complicated by the presence of the alignment patterns and the use of multiple interleaved error-correction blocks.

QR Barcodes - Structure

QR Barcodes - Structure

QR Barcodes - Structure

QR Barcodes - Examples

QR Barcodes - Examples

QR Barcodes - Examples