When you checkout from a supermarket, the person at the counter checks all that you have bought by flashing a small light at a set of lines marked somewhere on every item. How does this system of checking work?
A barcode is machine-readable information. It allows data to be collected accurately and rapidly about the product such as what product it is, the country where it was manufactured, prices, stocks left and so on.
A Barcode symbol consists of a series of parallel bars and spaces. Each of these wide and narrow bars and spaces in the pattern represents a character which in turn represents some kind of a code. Such as, numbers 00-13 is the country code for USA and Canada, 45 for Japan and 890 for India.
How is the barcode read?
A barcode reader uses a scanning device which is basically a photo sensor. It measures the relative widths of the bars and spaces, translates the different patterns back into regular characters, and sends them on to a computer or portable terminal. Here the original data is recovered. A bar code works like a light when turned on in a dark room. You see the walls and furniture in the room by the light reflected from these items.
The scanning device contains a small sensory reading element. This sensor detects the light being reflected back from the bar code, and converts the light energy into electrical energy. The result is an electrical signal that can be converted into data. Scanners employ various technologies to “read” codes. The two most common are lasers and cameras. Scanners may be fixed position type or hand-held devices.
History of Barcodes
In 1948, a local food shop owner Philadelphia (Pennsylvania) requested Bernard Silver, a research student to devise a method of automatically reading product information during checkout. Bernard Silver joined together with fellow research student Joseph Woodland to work on a solution. After four years of hard work, Woodland and Silver developed a method of “article classification through the medium of identifying patterns” and got it patented on the 7 October 1952.
Thus began the system of barcodes. The first product to have a bar code was Wrigley’s Gum. Bar codes were first used commercially in 1966, but it was soon realized that there would have to be a common standard all over the world to derive maximum benefit.
The Universal Product Code (UPC) was the first bar code symbology to be widely adopted. This was on 3 April 1973. Foreign interest in UPC led to the adoption of the EAN (European Article Numbering) code format, similar to UPC, in December 1976.
Currently, the United States and Canada use UPC bar codes as their standard for retail labeling, whereas the rest of the world uses EAN. Numerous other methods of bar-coding have evolved ever since. Originally barcodes were, stored data in the widths and spacing of printed parallel lines, but nowadays they also come in patterns of dots, concentric circles, and hidden in images. Also today we have numeric-only barcodes, alphanumeric barcodes and 2-Dimensional barcodes.
Consider a barcode found on a loaf of bread which contains a 12-digit product number. When this number is scanned by the cashier, it’s transmitted to the store’s computer which finds the record associated with that item number in its database. The matching item record contains a description of the product, vendor name, price, quantity-on-hand, etc. The computer instantly does a “price lookup” and displays the price on the cash register (it also subtracts the quantity purchased from the quantity-on-hand.) This entire transaction is done instantly; think of how long it would take the cashier to key in a 12-digit number for every item you wanted to buy!
Barcodes are thus a time saving, cost effective and accurate means of handling and checking large numbers of consumer goods.
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