Another name for barcode readers is the barcode scanners. These are the computer peripherals that are used to read the barcodes present on various surfaces. A fast and accurate transfer of encoded information has been done by these barcode readers into the application. The whole equipment comprises a light source, a lens, and a photo conductor for converting optical signals into electrical. In addition to these, decoder circuitry is also used to evaluate the barcode’s figures given by the photo conductor and then this information is sent to the reader’s output.

Classification of barcode readers

In the market mainly four types of barcode readers are available. These all use different techniques to read and decode a barcode.

1. Pen type readers: A light source and a photo diode are used here that are present in the tip of a pen or wand. The tip of the pen has to be moved all over the bar code with a fixed movement. The intensity of the light reflected back from the light source is measured by the photo diode and a wave form is generated. The light is absorbed by the dark bars and it is reflected by the white ones. Then this waveform is decoded by the reader.

2. Laser Scanners: Here a laser beam is used instead of the light source as in the pen type readers. A reflecting mirror or a rotating prism is used to scan the laser beam back and forth on the bar code. A photo diode is used to measure the intensity of the reflected light.

3. CCD Readers: Charge Coupled Device (CCD) readers involve a series of tiny light sensors located on the head of the reader. Like a photo diode each sensor is used to measure the light intensity. A voltage pattern similar to the bar code is generated in the reader serially measuring the voltages on each sensor.]

4. Camera-Based Readers: Here a small video camera is used to cover an image of a bar code. In these readers a very complicated digital image processing technique is used to decode the bar code.

Applications

The main areas where the barcode readers are useful are retail, warehouses, and industrial areas. Entertaining areas such as movies and music use the barcode readers in the DVD/VHS movie catalogs, CD and MP3 catalogs. Nutrition data in shopping malls can be read by these readers. For insurance and other purposes personal property inventory gathered in terms of bar codes, these readers are useful.



Source by Allan Wilson

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