Datamatrix
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Datamatrix is a two-dimensional matrix barcode consisting of black and white square modules arranged in either a square or rectangular pattern. The information to be encoded can be text or raw data. Usual data size is from a few bytes up to 2 kilobytes. The length of the encoded data depends on the symbol dimension used. Error correction codes are added to increase symbol strength: even if they are partially damaged, they can still be read. A Datamatrix symbol can store up to 2,335 alphanumeric characters.
Datamatrix symbols are square and made of little modules, that is little squares that represent bits. Depending on the situation a white module is a 0 and a black module is a 1, or vice versa. Every datamatrix is composed of at least two finder patterns or handles and two syncs. Handles are two perpendicular lines, coloured the same way as 1 modules, while syncs are like handles with the difference that they are made of alternating black and white modules. Handles are used to achieve a good alignment with the symbol, while syncs are used to sample modules correctly. If the matrix dimension grows, more syncs and handles are added up to 8 both horizontally and vertically. Symbol sizes vary from 8×8 to 144×144.
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[edit] Applications
The most popular applications for Datamatrix are marking of small items, due to the code’s ability to encode fifty characters in a symbol that is readable at 2 or 3 mm2 and the fact that the code can be read with only a 20% contrast ratio.
The Electronic Industries Alliance (EIA) recommends using Data Matrix for labeling small electronic components.
[edit] Technical Specifications
Datamatrix symbols are made up of square modules arranged within a perimeter finder pattern. It can encode up to 3,116 characters from the entire ASCII character set (with extensions). The symbol consists of data regions which contain square modules set out in a regular array. Large symbols contain several regions. Each data region is delimited by a finder pattern, and this is surrounded on all four sides by a quiet zone border (margin).
Symbols have an even number of rows and an even number of columns. Most of the symbols are square with sizes from 10×10 to 144×144. Some symbols however are rectangular with sizes from 8×18 to 16×48. All symbols can be recognized by the upper right corner module being light (binary 0).
ECC200 is the newest version of Datamatrix and supports advanced encoding error checking and correction algorithms (such as Reed-Solomon). This algorithm allows the recognition of barcodes that are up to 60% damaged.
[edit] Standards
Datamatrix was invented by RVSI Acuity CiMatrix. Today it is covered by an ISO standard, ISO/IEC16022—International Symbology Specification, Datamatrix, and is in the public domain, which means it can be used free of any licensing or royalties.
- ISO/IEC 15418:1999 – Symbol Data Format Semantics
- ISO/IEC 15434:1999 – Symbol Data Format Syntax
- ISO/IEC 15415 – 2-D Print Quality Standard
[edit] See also
[edit] References
- ↑ Laser Marking Matrix Codes on PCBs by Rick Stevenson, Printed Circuit Design and Manufacturing 2005-12
