How do barcodes work?

Answer 1

A barcode (also bar code) is a machine-readable (uses dark ink on white substrate to create high and low reflectance which is converted to 1's and 0's) representation of information in a visual format on a surface. Originally barcodes stored data in the widths and spacings of printed parallel lines, but today they also come in patterns of dots, concentric circles, and hidden within images.

The mapping between messages and barcodes is called a symbology. The specification of a symbology includes the encoding of the single digits/characters of the message as well as the start and stop markers into bars and space, the size of the quiet zone required to be before and after the barcode as well as the computation of a checksum.

Linear symbologies can be classified mainly by two properties:

* Continuous vs. discrete: Characters in continuous symbologies usually abut, with one character ending with a space and the next beginning with a bar, or vice versa. Characters in discrete symbologies begin and end with bars; the intercharacter space is ignored, as long as it is not wide enough to look like the code ends.
* Two-width vs. many-width: Bars and spaces in two-width symbologies are wide or narrow; how wide a wide bar is exactly has no significance as long as the symbology requirements for wide bars are adhered to (usually two to three times more wide than a narrow bar). Bars and spaces in many-width symbologies are all multiples of a basic width called the module; most such codes use four widths of 1, 2, 3 and 4 modules.

Some symbologies use interleaving. The first character is encoded using black bars of varying width. The second character is then encoded, by varying the width of the white spaces between these bars. Thus characters are encoded in pairs over the same section of the barcode. Interleaved 2 of 5 is an example of this.

Stacked symbologies consist of a given linear symbology repeated vertically in multiple.

There are a large variety of 2-D symbologies. The most common are matrix codes, which feature square or dot-shaped modules arranged on a grid pattern. 2-D symbologies also come in a variety of other visual formats. Aside from circular patterns, there are several 2-D symbologies which employ steganography by hiding an array of different-sized or -shaped modules within a user-specified image (for example, DataGlyph).

Answer 2

How Do Barcodes Work

Answer 3

The technology is simple and easy to understand. A barcode is a machine readable representation of information in a visual format. Barcodes store data in the widths and spacing of printed parallel lines and can be read by optical scanners. To be scanned, there must be accurate printing and adequate contrast between the bars and spaces. Scanners may be in a fixed position, like most supermarket checkout scanners, or hand-held devices, often used for the taking of inventories.

Since their invention in the 20th century, the use of barcodes is widespread and the technology behind barcodes is constantly improving. Practically every item purchased from a store has a barcode on it. This greatly helps in keeping track of the large number of items in a store and also reduces instances of shoplifting. Rental car companies keep track of their cars by means of bar codes on the car bumper. Even airlines track passenger luggage with barcodes, reducing the chance of loss. Even NASA uses them to keep track of maintenance.

For more info visit:
http://missknowall.blogspot.com/2006/06/how-do-barcodes-work.html

Answer 4

I think theyre kinda cool. I saw someone on tv get a barcode tattoo, and had their birthday digits put on it. Thought it was a wicked idea.

Answer 5

by electronic machines