Professor Koon ISE 370 Barcodes. Professor Koon ISE 370 Code Reading Technology Original Barcode Readers Contact Wand

Professor Koon ISE 370

Barcodes


Code Reading Technology

Original Barcode Readers Contact Wand



Non-Contact Scanner How a checkout scanner

works Optoelectronics:

Optical Image to electrical Signals



Non-Contact Scanner




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/uploaded/scaled/Shop_s.jpg


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


UCC >> First BarCode (1974)

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.


Decode BarcodeBlack Bars with White Bars

BetweenThinnest Bar = 1 unit wideAll Bars 1 to 4 units wideStart (L) is 1-1-1 (B-W-B)Final ( R) is 1-1-1 (B-W-B)All Digits add to 7 widths



UPC Barcode How to read a standard 12 decimal digit code

Digit

PatternDigit

Pattern

00001101

50110001

10011001

60101111

20010011

70111011

30111101

80110111

40100011

90001011


How To Read a Barcode

Check Digit (UPC Code)Add all digits in Odd positionsMultiply sum results by 3Add all digits in Even positionsAdd 3x Odd sum to Even sumThis sum plus check digit must

be a multiple of 10. (e.g. 110)

Try 63938200039Professor Koon ISE 370


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)

Interleaved 2 of 5Numbers OnlyLong as NecessaryCheck Digit is optionalDigit is encoded in the barsNext digit is encoded in the spacesStart >> NB-NS-NB-NSData = five bars eachStop >> WB-NS-NB


Number Pattern 2 of 5 0 >> NNWWN 1 >> WNNNW 2 >> NWNNW 3 >> WWNNN 4 >> NNWNW 5 >> WNWNN 6 >> NWWNN 7 >> NNNWW 8 >> WNNWN 9 >> NWNWN




American Standard Code for Information Interchange (ASCII) Coding Standard


Different Types of Barcodes>> 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



Code 128 A very high-density barcode symbology Used extensively world wide in shipping and packaging

industries Can encode all 128 characters of ASCII

CODE 49


Code 492 to 8 rows stacked Cross between UPC & Code 39Developed in 1987 Intermec

Corp. Modified Scanner Needed




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).

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.

3D Barcode (Bumpy)

Small circular symbols Shiny, curved metal surfaces


SuperCode

In public domain.Invented in 1994.Packet structure (multi-row).Greater freedom in placing

packets.32 error correction levels.



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

Professor Koon ISE 312 2704/19/23

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

Professor Koon ISE 312 2804/19/23

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/wiki/Barcode


Questions?

Documents

Professor Koon ISE 370 Barcodes. Professor Koon ISE 370 Code Reading Technology Original Barcode Readers Contact Wand