Barcodes

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Barcodes
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Code Reading Technology

• Original Barcode Readers
• Contact Wand

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Code Reading Technology

• Non-Contact Scanner
• How a checkout scanner works
• Optoelectronics
• Optical Image to electrical Signals

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Code Reading Technology

• Non-Contact Scanner

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Code Reading Technology
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BarCode History

• Grocery stores need for a system to automatically
  read items at checkout
• Increase Productivity
• Reduce Human Error
• Silver, Woodland and Johanson
• 1948 Drexel Institute of Technology Students
• 1949 First patent for Classifying Apparatus and
  Method
• Linear
• Bulls-eye

Image http//www.ournewhaven.org.uk/images/upload
ed/scaled/Shop_s.jpg
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Standardization

• Without the advancements involving lasers and
  microchips, the development of the Universal
  Product Code and the dream of an automated
  checkout would not have been possible. Marvin
  L. Mann

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UCC gtgt First BarCode (1974)
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UPC Universal Product Code12 Digits (6
ID, 5 item, 1 check)Symbology is a standard
that defines the printed symbol.How scanners
should read and decode the symbol.
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Decode Barcode

• Black Bars with White Bars Between
• Thinnest Bar 1 unit wide
• All Bars 1 to 4 units wide
• Start (L) is 1-1-1 (B-W-B)
• Final ( R) is 1-1-1 (B-W-B)
• All Digits add to 7 widths

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UPC Barcode

• How to read a standard 12 decimal digit code

Digit Pattern Digit Pattern
0 0001101 5 0110001
1 0011001 6 0101111
2 0010011 7 0111011
3 0111101 8 0110111
4 0100011 9 0001011

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How To Read a Barcode
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Check Digit (UPC Code)

• Add all digits in Odd positions
• Multiply sum results by 3
• Add all digits in Even positions
• Add 3x Odd sum to Even sum
• This sum plus check digit must be a multiple of
  10. (e.g. 110)
• Try 63938200039

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Different Types of Barcodes

• Other most commonly used codes
• UPC-A, UPC-E, and UPC Supplemental
• EAN-13 (13 Digits One for Flag)
• Code 39 (US Military 1981)
• Interleaved 2 of 5
• Code 128 (Alphanumeric)
• Two-Dimensional (Stacked, Multi-row)

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Interleaved 2 of 5

• Numbers Only
• Long as Necessary
• Check Digit is optional
• Digit is encoded in the bars
• Next digit is encoded in the spaces
• Start gtgt NB-NS-NB-NS
• Data five bars each
• Stop gtgt WB-NS-NB

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Number Pattern 2 of 5

• 0 gtgt NNWWN
• 1 gtgt WNNNW
• 2 gtgt NWNNW
• 3 gtgt WWNNN
• 4 gtgt NNWNW
• 5 gtgt WNWNN
• 6 gtgt NWWNN
• 7 gtgt NNNWW
• 8 gtgt WNNWN
• 9 gtgt NWNWN

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Different Types of Barcodes

• American Standard Code for Information
  Interchange (ASCII)
• Coding Standard

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Different Types of Barcodesgtgt Linear or Matrix
(2D)

• Code 39
• A symbology that can encode uppercase letters (A
  through Z), digits (0 through 9) and a handful of
  special characters like the sign.
• Military Usage
• Drawbacks
• Low Data Density
• Requires More Space

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Different Types of Barcodes

• Code 128
• A very high-density barcode symbology
• Used extensively world wide in shipping and
  packaging industries
• Can encode all 128 characters of ASCII

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CODE 49
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Code 49

• 2 to 8 rows stacked
• Cross between UPC Code 39
• Developed in 1987 Intermec Corp.
• Modified Scanner Needed

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Different Types of Barcodes

• Data Matrix
• A 2D matrix barcode consisting of black and white
  cells or modules arranged in either a square
  or rectangular pattern.
• Most common in marking small items (as small as
  2-3mm2)
• Pack a lot of information in a very small space.
  Stores between 1 to 500 characters. Can scale
  down to 1 mil square. (500 million characters per
  inch).

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Aztec Code

• Design for ease of printing ease of decoding
• Square central bullseye finder.
• Smallest 15 x 15 modules.
• Largest 151 x 151 modules.
• 1995 by Welch Allyn Inc.

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3D Barcode (Bumpy)

• Small circular symbols
• Shiny, curved metal surfaces

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SuperCode

• In public domain.
• Invented in 1994.
• Packet structure (multi-row).
• Greater freedom in placing packets.
• 32 error correction levels.

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Radio Frequency Identification(RFID)

• No contact of line of sight
• Active or Passive Tags (See note sheet)
• Electromagnetic Waves
• Active tags contain a battery and
• can transmit signals autonomously.
• Passive have no battery and require
• an external source to provoke signal
• Transmission.
• Cost under 10
• Implementation into cell phones

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Standardization

• Problems with standardizing new technology
• Will Barcodes Prove to be Economic?
•  IBM proposed designed by George J. Laurer
• 12 Decimal Digit code -SLLLLLLMRRRRRRE
• (S) Start Bit pattern of 101
• (L) Left 7 Bit pattern
• (M) Middle Bit pattern of 01010 known as
  guard bars
• (R) Right 7 Bit pattern
• (E) End Bit pattern of 101

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What is a Barcode?1

• A bar code (also barcode) is an optical machine
  readable representation of data.
• Originally, bar codes represented data in the
  widths (lines) and the spacings of parallel lines
  and may be referred to as linear or 1D barcodes
  or symbologies.
• Now they also come in patterns of squares, dots,
  hexagons and other geometric patterns within
  images termed 2D matrix codes or symbologies.

1 Image and Definition http//en.wikipedia.org/wi
ki/Barcode
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Questions?