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Barcodes are machine-readable data codes that serve a broad range of organizational and financial applications. Barcodes are used to keep track of shipments, price retail items, manage financial documents, and to perform many other logistical and organizational services because a large number of coded information can be translated into barcode symbology, and then scanned and read by different types of barcode readers. There are four primary types of barcode readers that are each designed to fulfill specific information needs.
Barcodes, such as UPC codes, use thin and thick bar patterns to represent data while more complex coding systems, known as 2D matrix codes, use intricate patterns of blocks and arrangements to store masses of information. Both types of barcode are able to store information for later use if read by a barcode scanner, which reads the barcode and then uses software to convert the optical code information into a digital signal. The digital signal is then sent on to perform another function, such as representing information on a digital read out or logging stock in an inventory database.
Four Types of Barcode Readers
Pen barcode readers resemble small wand-type sticks that resemble a small pen. The pen-style barcode reader consists of an LED light and a photodiode in its tip. The user passes this tip over a barcode and the LED light illuminates the black and white bars. The photodiode measures the reflection of light and is able to determine width and color (white or black) of each bar. This information allows for a digital reading of the barcode, and information is transmitted to another unit for processing.
Pen or wand barcode readers are designed for durable, inexpensive use by a single user who can quickly scan packages or other items. However, because of the shakiness and imprecision of human use, the user may need some practice to perfect the scan.
Slightly more advanced than a pen scanner, a laser barcode scanner is capable of more exact light readings which prevent false positives or scanner errors. In a laser scanner, a laser beam is shot at a mirror inside the actual unit. This mirror makes a movement so that the laser sweeps across the barcode in a straight line. This light then reflects back to a diode, which measures the level of reflection. This reflection is translated into a digital signal readout of the barcode. Laser scanners can either be mounted in a scanning unit or be part of a handheld unit.
A charge coupled device (CCD), also known as an LED scanner, features hundreds of tiny LED lights arranged in one long row. These lights are shot directly onto a barcode, and a sensor then measures not the reflection, but voltage of the ambient light directly in front of each lightbulb. This voltage measurement provides a digital snapshot of the barcode. CCD units can be very expensive, but are highly accurate and versatile pieces of equipment.
Some barcodes do not consist of white and black bars, but white and black spaces in a two-dimensional (2D) target. These 2D barcodes cannot be read by standard machinery, but they do allow for versatility of information coding as they can hold and provide much more data than a standard barcode. To read these barcodes, a 2D camera image scanner is necessary. This camera consists of hundreds of tiny lights like the CCD scanner, but these are arranged in multiple rows. The lights flash onto the barcode and take a digital picture of the barcode, which is then sent to software as a digital signal. The software then decodes the information.
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