## Monday, July 16, 2012

### barecode reader;What does a barcode contain? Is a barcode readable? Test and control barcodes!

an image (via a webcam for example)-->EAN code ( a number)

Reads barcodes from images. Supported symbologies: Code 128, Code 39, EAN-8, EAN-13, UPC-A, UPC-E, Interleaved 2 of 5, Codabar, EAN-2 and EAN-5, DataMatrix and PDF 417.

http://www.bctester.de/en/index.htm
bcTester reads barcodes from images or PDF files. Linear barcodes can be recognized as well as modern 2D-(two dimensional) barcodes
Find out what is encoded in the barcodes you see!
Just create an image file by scanning or taking a picture of the barcode, and bcTester reads it from the file.

Rem:
A barcode is an optical machine-readable representation of data relating to the object to which it is attached.http://en.wikipedia.org/wiki/Barcode
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.
A barcode reader or barcode scanner is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones. Additionally, nearly all barcode readers contain decoder circuitry analyzing the barcode's image data provided by the sensor and sending the barcode's content to the scanner's output port.
The Symbology Decoding Algorithm for barcode scanners is the first symbology-based algorithm for decoding. The new technique utilizes information from the entire image to detect transitions in the signal, whereas the traditional algorithm relies on the maxima and minima. Traditional methods are prone to errors because the method relies on a derivative; they are also sensitive to noise and blurring. The Symbology Decoding Algorithm for Bar Code Scanners exhibited high resilience to blur and noise when tested on 1D Universal Product Codes. The algorithm can also be extended for use on 2D Universal Product Codes
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#### Which product is behind an EAN number ?

http://www.ean-search.org/

#### Meaning of code:

http://www.dcode.fr/code-barres-code-128

http://en.wikipedia.org/wiki/GS1-128

on android: