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2DTG unveils Upgrade to its DataMatrix Decoder, Enterprise Edition – Release 13.04

Mon, 2013-04-29

This release introduces the new image pre-processing filter - “AG Filter” (“Adjust Grid” Filter) for DataMatrix decoding. It is designed to compensate for excessive scores of Data Matrix Grid Non-Uniformity.

Grid Non-Uniformity (GNU) refers to a symbol’s cell deviation from the ideal grid of a theoretical “perfect symbol”. The Data Matrix reference decode algorithm is applied to a binarized image of the symbol, comparing its actual grid intersections to ideal grid intersections. The greatest distance from an actual to a theoretical grid intersection determines the Grid Non-Uniformity grade.

ISO/IEC 15415 defines Grid Non-Uniformity grades as follows:

  • 4 (A) if grid non uniformity ≤ 0.38
  • 3 (B) if grid non uniformity ≤ 0.50
  • 2 (C) if grid non uniformity ≤ 0.63
  • 1 (D) if grid non uniformity ≤ 0.75
  • 0 (F) if grid non uniformity > 0.75

Normally, Data Matrix symbols with a GNU score of ~ 0.7 (Grade 1) or higher are considered “non-decodable”.

AG Filter allows compensating for the large GNU scores within reason. It is designed for both colors of Data Matrix: “Black-on-White” and “White-on-Black”. The filter does not, practically, affect the “average decodability” of regular images and dramatically improves the decodability of images having low GNU grades.