In 1932 a small group of students from Harvard University, London first developed the concept
of Automatic Product Identification By passing a high intensity light through some Morse Code.
Which gradually developed to Bar-coding system from the year, 1948. Soon the bar-coding
technology opened for public use from, 1967.
In 1974, the first the first bar coding was introduced to the retail world on a packet of Wrigley’s
Gum. Thirty eight years later the number of applications for bar code technology has exploded,
going far beyond grocery stores and retail. Read between the lines and you will see bar code
technology popping up in new and unusual places such as hospitals, law firms, retail stores,
security, and Department of Defense, corporate offices, libraries, and rental cars.
Figure 1.1 :- Barcode & Barcode Reader
2. BARCODING TECHNOLOGY
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
spacing's 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
The Laser Light Scans the barcode & generates wave-form from the light reflected back from the
white areas of the barcode.There are Two Quiet Zones at the two ends of the barcode, then it has
a start checkpoint & end checkpoint at it's two sides, after the start point it contains the actual
data then a check symbol validates the existence of the scanned code.
Figure 2.1 - Barcode Design Construction
Figure 2.2 - Barcode Construction Rules
3. BAR CODE SYMBOL CHARACTERISTICS
The magnification (size) of the bar code symbol is determined by the X-dimension (one narrow module
width) in relation to a nominal size.
The allowable magnification range depends on the symbol type and the intended scanning environment.
Reliability of scanning is always enhanced by selecting a magnification higher than the minimum.
To print an accurate and high quality bar code symbol a number of factors, such as the printing process,
ink quality, and substrate, must be taken into consideration.
2. Bar Height
Once the magnification of the bar code symbol has been determined, for EAN/UPC Bar Code
symbols it is important to ensure that the height remains in proportion to the magnification, and
does not drop below the minimum specified.
3. Quiet Zones (Light Margins)
The Quiet Zones (Light Margin) of the bar code symbol are the solid, light areas before the first
bar and after the last bar. These areas are extremely important as they allow the scanner to
recognise the beginning and end of the bar code symbol.
Any obstruction or reduction in the Quiet Zones will most likely result in scanning difficulties.
The minimum size required for the Quiet Zones depends on the magnification of the bar code
It is recommended to allow slightly more than the minimum required Quiet Zones to allow for
any possible ink spread or plate registration issues.
The colours and type of ink you choose for your bar code symbols is very important. As a scanner reads a
bar code symbol using an infrared light source it sees the symbol differently to the human eye.
As a result, some colour combinations and ink types are unsuitable for scanning because they do
not provide sufficient contrast between the dark bars and the light background, or they provide a
much too high reflectance value.
The most suitable and reliable colour combination is black bars on a white background.
However, as a general rule, the background of the bar code symbol can be a light, warm colour
that does not contain any black (such as yellow or light orange), and the bar colour can be a dark,
cool colour that has no, or low, red content (such as dark blue or dark green).
The substrate (the material the bar code symbol is printed on) is very important. If unsuitable this can
cause scanning difficulties. Different packaging materials reflect light differently, which can have an
effect on the scanning ability of the bar code symbol.
This is especially evident on transparent and translucent packages where the background is not printed.
For printing bar code symbols it is recommended that you avoid the following:
• High gloss substrates
• Transparent or semi-transparent backgrounds
• Transparent wrappers over the printed bar code symbol if necessary to print onto a highly reflective
(flexible) substrate, we recommend the following:
• Increase the magnification of the bar code symbol to between 105% and 120% (X-dimension 0.35mm -
• Increase the amount of Bar Width Reduction
• Make the background of the symbol as dense and less reflective as possible. To do this you may try the
• If you are not using wet inks, print two background layers. This may be two layers of the one colour, or
you may use all light colours in the print run (e.g. white and yellow)
• Use a less viscous ink that will provide maximum coverage and density
6. Bar Widths and Print Quality
Always ensure that the print quality of the bar code symbol is of a high standard. Ensure that the
bars in the symbol are clearly defined, watch for voids or smudging, and avoid flecks in the
Maintaining acceptable print quality and consistent print gain (ink spread) requires regular
4. ANATOMY OF BARCODES
Fig 4.1: Anatomy Of Barcodes
This number is a UPC system number that characterizes specific types of barcodes. In a UPC
barcode it is normally on the left of the barcode. The actual "barcode" (the "bars" and "spaces")
is the first "barcode" after the first "guard bar". The Number System Character is the blue box on
the "Anatomy of a Barcode".
Codes of the Number System Character:
• 0 - Standard UPC number.
• 1 - Reserved.
• 2 - Random weight items like fruits, vegetables, and meats, etc.
• 3 - Pharmaceuticals
• 4 - In-store code for retailers.
• 5 - Coupons
• 6 - Standard UPC number.
• 7 - Standard UPC number.
• 8 - Reserved.
• 9 - Reserved
5 .TYPES OF BARCODES
Codabar: Older code often used in library systems, sometimes in blood banks
Code 11: Used primarily for labeling telecommunications equipment
EAN-13: European Article Numbering international retail product code
EAN-8: Compressed version of EAN code for use on small products
Industrial 2 of 5: Older code not in common use
Interleaved 2 of 5: Compact numeric code, widely used in industry, air cargo
MSI: Variation of the Plessey code commonly used in USA
Plessey: Older code commonly used for retail shelf marking
PostNet: Used by U.S. Postal Service for automated mail sorting
UPC-A: Universal product code seen on almost all retail products in the USA and
Standard 2 of 5: Older code not in common use
UPC-E: Compressed version of UPC code for use on small products
Code 128: Very capable code, excellent density, high reliability; in very wide use
Code 39: General-purpose code in very wide use world-wide
Code 93: Compact code similar to Code 39
LOGMARS: Same as Code 39, this is the U.S. Government specification
PDF417: Excellent for encoding large amounts of data
DataMatrix: Can hold large amounts of data, especially suited for making very
Maxicode: Fixed length, used by United Parcel Service for automated package
QR Code: Used for material control and order confirmation
Industry Standards for Barcodes and Labels
Bookland EAN encodes ISBN numbers, used internationally to mark books
ISSN and the SISAC Barcode: International Standard Serial Numbering
OPC: Optical Industry Association barcode for marking retail optical products
UCC/EAN-128: Widely used data formatting model for Code 128
Fig5.1.Types of barcodes
6. STRUCTURE OF BARCODE
bar code correctly. It is typically stripped from the data and not transmitted to the host. Quiet
Zone: The minimum required space for bar code scan-ability, preceding the Start Character of a
bar code symbol. The quiet zone should be free from any printing and be the same color and
reflectance as the background of bar code symbol. The Quiet Zone should be ten times the width
of the narrowest element in the bar code, or 0.25 inch minimum, also known as Clear Area.
Start Code: Indicates the start of the barcode. These are special bar code characters & they
signify the start of data to the scanner/reader. Start characters are usually strippedoff and not
transmitted to the host.
Check Digit: Check digit (not always present) is a mathematical sum that is used to verify the
accuracy of the other elements of the barcode. It is the extra digit added at the end of a bar code
to allow the scanner to confirm that it read the
Stop Code: Indicates the stopping point of the barcode. These characters signify the end of data
to the scanner/reader. They are also stripped-off and not transmitted to the host.
Fig6.1: Barcode structure
7. WORKING OF BARCODE
Laser beam is incident on a mirror/prism which is then directed on the barcode from left to right.
The dark bars of barcode absorb the incident light but the light is reflected by light spaces.
Photodiode measures the reflected light and gives out electrical signal. The analog electrical
signal is then converted into digital one. And corresponding barcode is read.
Fig7.1: Working of Barcode
8. USE OF BARCODES
Barcodes such as the UPC have become a ubiquitous ele-ment of modern civilization, as
evidenced by their enthu-siastic adoption by stores around the world; most items other than fresh
produce from a grocery store now have UPC barcodes. This helps track items and also reduces
instances of shoplifting involving price tag swapping, al-though shoplifters can now print their
own barcodes. In addition, retail chain membership cards (issued mostly by grocery stores
and specialty “big box” retail stores such as sporting equipment, oﬃce supply, or pet stores) use
barcodes to uniquely identify consumers, allowing for customized marketing and greater
understanding of indi-vidual consumer shopping patterns. At the point of sale, shoppers can get
product discounts or special marketing oﬀers through the address or e-mail address provided at
Fig8.1.Example of barcode on a patient identification wristband
They are widely used in the healthcare and hospital set-tings, ranging from patient
identification (to access pa-tient data, including medical history, drug allergies, etc.) to creating
SOAP Notes with barcodes to medication management. They are also used to facilitate the
sep-aration and indexing of documents that have been im-aged in batch scanning applications,
track the organiza-tion of species in biology, and integrate with in-motion checkweighers to
identify the item being weighed in a conveyor line for data collection.
They can also be used to keep track of objects and people; they are used to keep track of rental
cars, airline luggage, nuclear waste, registered mail, express mail and parcels. Barcoded tickets
allow the holder to enter sports arenas, cinemas, theatres, fairgrounds, and transportation, and are
used to record the arrival and departure of vehicles from rental facilities etc. This can allow
proprietors to identify duplicate or fraudulent tickets more easily. Bar-codes are widely used in
shop floor control applications software where employees can scan work orders and track the
time spent on a job.
9. ADVANTAGES & DISADVANTAGES
Represent unique identity of a product
Accuracy of data input (error free)
Labour savings by avoiding manual system
More accurate despatch
Real time data collection
Measurement of work in progress throughout the factory
Rapid access to total production costs
Scratched or crumpled barcodes may cause problems
System Failure may cost more delays.
Data must be coded in the barcode
In laser scanning, durability and cost are the two disadvantages
CONCLUSION AND FUTURE SCOPE
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:
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.
The tracking of item movement, including rental cars, airline luggage, nuclear waste, mail and
Entertainment event tickets can have barcodes that need to be validated before allowing the
holder to enter sports arenas, cinemas, theatres, fairgrounds, transportation etc. This can allow
the proprietor to identify duplicate or fraudulent tickets more easily
 Barcode scanners. (2007). Wasp Technologies. Retrieved 5th March 2007 from
 M.R. Rieback, B. Crispo, and A.S. Tanenbaum, ―The Evolution of RFID Security,‖ IEEE
Pervasive Computing, vol. 5, no. 1, 2006, pp. 62-69.
 Clarke, D., Gosain, S., &Thillairajah, V. (2005). Realizing the promise of RFID. Retrieved
21st October 2007 from http://www.ebizq.net/topics/rfid/features/6165.html
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