Bar-code (50 mm)

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  A barcode or bar code is a method of representing data in a visual, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly referred to as linear or one-dimensional (1D), can be scanned by special optical scanner called barcode readers, of which there are several types.

Later, two-dimensional (2D) variants were developed, using rectangles, dots and other patterns, called 2D barcodes or matrix codes, although they do not use bars as such. Both can be read using purpose-built 2D optical scanners, which exist in a few different forms. Matrix codes can also be read by a digital camera connected to a microcomputer running software that takes a photographic image of the barcode and analyzes the image to deconstruct and decode the code. A   Mobile device with a built-in camera, such as a Smart phone, can function as the latter type of barcode reader using specialized application software and is suitable for both 1D and 2D codes