Barcode reader
To read a barcode, the person holding the pen must move the tip of it across the bars at a relatively uniform speed.
The design may include a focusing device, enabling the scanner to adjust the beam to scan at various distances.
To accommodate stationary items, laser scanners incorporate oscillating mirrors that provide additional deflection perpendicular to the main scanning line.
The reflected light, rapidly varying in brightness with a data pattern, is then converted into an electrical signal and is subsequently amplified to a usable level for digital processing.
Large field-of-view readers use high resolution industrial cameras to capture multiple bar codes simultaneously.
All the bar codes appearing in the photo are decoded instantly (ImageID patents and code creation tools) or by use of plugins (e.g. the Barcodepedia used a flash application and some web cam for querying a database), have been realized options for resolving the given tasks.
Omnidirectional scanning uses "series of straight or curved scanning lines of varying directions in the form of a starburst, a Lissajous curve, or other multiangle arrangement are projected at the symbol and one or more of them will be able to cross all of the symbol's bars and spaces, no matter what the orientation.
Unlike the simpler single-line laser scanners, they produce a pattern of beams in varying orientations allowing them to read barcodes presented to it at different angles.
There are a range of different omnidirectional units available which can be used for differing scanning applications, ranging from retail type applications with the barcodes read only a few centimetres away from the scanner to industrial conveyor scanning where the unit can be a couple of metres away or more from the code.
Today the term is used more broadly for any device which can be plugged in and contribute to the stream of data coming "from the keyboard".
Readers without external power sources require their batteries be recharged occasionally, which may make them unsuitable for some uses.
On the other hand, if a too small dot of light is used, then it can misinterpret any spot on the bar code making the final output wrong.
