Barcode

1. History

It is in 1948, when a food company president expressed the need of an automatic solution for products data seizure at his shops’ cashiers. The automatic subtraction of sold goods to his stock would have provided him a real-time and economical stock control. The idea was not a new one, the system of punch cards developed in 1890 to realize the United States census had already allowed such an automation.

Norman Joseph Woodland professor in « Philadelphia Drexel Institute of technology » will be informed about it and will passionate himself for the project to which he will dedicate several months to present a solution named « linear code bar », diverted evolution of the fusion of the system of film sound coding system and the morse code.

The first patent was deposited in 1949. Unusable as it was, we have to wait for 1969 to see the technology matures. The company “Computer Identique Corporation” installs the first « handmade » barcodes readers using a milliwatt laser beam. Four years later, the "Universal Product Code " developed by IBM helped by Woodland, employee of the company and inventor of the barcode, standardizes the codification. The improvement of computers allowing to store, to translate and to treat this codification allows then the suppliers of the distribution various sectors to make quick returns on investments in the identification of their products. From 1970 till 1980 all the standards of codification are developed, multiplied to answer the various sectors requirements. From 1988 till 1995 the codes named "piled" and "bidirectional or matrix" appear to answer the of storing more and more information; some using the same reading technology, the others even requiring a camera! In the same time, the European and world standards are stopped in 1993 limiting itself to the first code type invented by Woodland, the linear barcode.

2. What is a barcode ?

A barcode represents the graphic codification of an information. Varying according to the algorithms, this codification is optimized according to needs to encode text, figures, characters of punctuation or another combination of them. The obtained representation is optimized for an optical character reading. Bars have to contrast with blank spaces, which explains why these are often black on white background. It is necessary to understand that blank spaces are also used to codify the information.

3. Why do we use barcodes?

 “The barcode is to the machine what the alphabet is to the man”

3.1. A technology imposes itself.

Until the barcode invention, the management of any operation follow-up was realized by a handwritten identification of the object or the document. From the beginning of the computerization, this information was inputed-in manually by operators of seizure, in charge of filling databases to store, to treat, to communicate and to exploit the information collected more effectively. This last operation of seizure was long and subject to errors. It owed be substituted.

The logic of production costs reduction and the seek for the "zero defect", have multiplied barcode technique applications within the past few years.

The barcode is today’s most used technical solution to acquire automatically an information. This established fact has for origin the massive computerization of the companies of the last years as well as the numerous qualities of the barcode realizing the connection between paper and data processing.

Among its qualities, let’s quote:

Reading reliability and speed, ( reading error of 1/20.000 – 2.000.000, according to the codification.

Information redundancy over all the height of the code allows guaranteeing the information even if a part of the code is illegible due to printing defects, light tears or frictions.

Easiness and low cost of barcode printer are exemplary, supports and printing consumables from many different technologies are available. The barcode can be easily mixed with other information used in labeling and then sees its cost decreasing very often.

The flexibility of the barcode allows accepting variable dimensions, readings by various types’ readers, useful information whatever the orientation of the code …

Why don’t we use alphanumeric characters that we all know?

The technique indeed allows the automatic characters recognition (OCR), but the error rate is too important and the implementation very delicate.

3.2. What usage for barcodes?

The barcode allows limiting the time spent in seizure for a product follow-up in a manufacturing process orr for a document circulating within a service, within a company or within a supplier/customer relationship.

The automatic reading authorizes the interconnection of information systems and their real time update.

In the distribution sector, the barcode allows among others:

- To enter quickly a product in stock,

- To know the origin of the product,

- To facilitate the resupplying,

- To automate stock releases and obtain a permanent simplified inventory,

- To optimize processing time at cashiers

In a manufacturing plant, the barcode also allows:

- To know raw material origin,

- To have continuously updated information about the production status,

- To direct automatically a product according to its characteristics, to its defects,

- To identify its production,

- To identify the logistic units distributed to ones customers.

4. How does a barcode work?

The contrast as a source of information.

During the passage of a light source on the dark and clear bars of a barcode, the luminous intensity ( the reflectivity) varies. This one, captured by a photo-sensitive receiver, is amplified, filtered and digitalized to be converted in numerical information which a decoder retranscribes in ASCII characters directly usable by a computer system by wire or wire-less connection.

5. Barcodes readers

5.1. Pen reader

They are the simplest reading devices. The pencil makes the reading by a manual passage on the barcode. Realized with a physical contact, the reading quality varies according to the pencil inclination and depends a great deal of the constancy with which the code is gone through.

Its small price makes it a model adapted to reduced reading needs, possibly a control tool of the coded information.

5.2. CCD reader

The CCD reader allows an automatic barcode reading, no need to go through the entire code and each of its bars like with the pen. There is no contact, the distance of reading is variable (up to 20 cms) and depends on adjustments brought to the reader. The more the distance is important, the more the code lighting is weak.

The CCD devices do not contain mechanical elements and offer generally a high robustness.

More economic than the laser models, the CCD reader is able to read all linear barcodes. Certain models are able to read the piled codes (PDF417).

5.3. Laser reader

Built around mirrors set, the laser reader uses a single beam of light generated by one laser diode. The light source is dense and precise, and allows a close or several meters distance reading as well as a in motion object reading. Quite as the CCD readers, the laser readers realize an automatic reading of the code. No need to go through the barcode, a motorized mirror is doing it by reflecting the laser beam on both sides of the code giving the optical illusion of a continuous linear beam. Certain readers also allows this scanning on the height of the code (Raster), others multiply the scanning with the aim of obtaining a laser “grid” under which the code can be placed in whatever orientation (multidirectional)

6. How to choose the good type of barcode?

Difficult to decide on the most suitable codification for your project, especially in front of the multitude of existing codes. A small reading of the following paragraph should quickly limit your choice!

6.1. Existence of inter-professional standards.

Standard or free will, consult before choosing

6.1.1. Standards by sectors.

The first question to answer must be the following one: do I need to use my sector define standard?

Indeed, numerous sectors already defined their own barcode standard according to their sectors needs and requirements. Inquire, at first, with your professionals partners, suppliers and customers.

The inter-professional standards specify the type of codification, location of the barcode on the document or the label, dimension of the code, its bars, its height, the structure of the codified information, the text that must goes with the code …

6.1.2. The main standards.

The distribution & editing sectors use GENCOD.

- EAN 13: For the consumer units identification (the product)

- ITF: For the packaging units identification (the packaging)

- EAN 128: For the expedition units identification. (the pallet, or possibly the cardboard)

The automotive industry uses GALIA.

- CODE 39 : Built around the code 39, this standard identifies the expedition and packaging units exchanged between the parts manufacturers and the car manufacturers.

The pharmaceutical industry uses CIP - Inter Pharmaceutical Club.

- CODE 39: (In France and in the majority of the European countries) For the consumer units identification (the product)

- CIP HR (2/5): Specific to the French market.

Third Party Logistics - Carriers

- GTF: Defines the barcode structure including among others the postal code, carrier id, sender id, parcels qty, etc…

6.2. Non-existence of inter-professional standards

When there’s no existing standard for your activity, various questions can help to limit your choice:

- Is the information to be coded digital or alphanumeric? (Codification)

- What is the available size for the barcode? (Dimension)

- What is the required security level? (Reliability of the read information truthfulness)

- Is there a codification constraint for the reading devices? (linear code/piled code/2D code/resolution)

- Is there a codification constraint for the printing material? (Resolution)

- Is there a reading constraint? (Distance of reading, available locations for the reader, code motion during the reading)

7. Most wide-spread barcodes

Source :  https://www.mds-identification.fr