engleski

Readability of multi-colored 2D codes

Datamatrix codes can be successfully read with a code reader or with mobile phone if the code is printed with appropriate contrast between the printing ink and the substrate. The readability of Datamatrix codes printed separately with pure process colors was studied. It was proved that yellow codewords may cause a reading failure. The readability of dichromatic and multi-colored Datamatrix codes was also studied. Datamatix codes are capable of ensuring good readability even if they contain a substantial number of poorly readable codewords due to the Reed-Solomon error correction system. The multi-colored Datamatrix codes were printed on four different substrates and the code readability using two different camera-based readers was determined. The results revealed that all multi-colored codes with two yellow codewords printed with an inkjet and laser printer were readable on all printing substrates if they were captured with mobile phone. When capturing with a conventional reader an exception appeared on one printing substrate. This phenomenon was studied in detail with the evaluation of substrate whiteness and by measurements of L*a*b* values, chroma (C*) and optical density (D) of printed colors. All codes with three yellow codewords were unreadable regardless of the printing substrate, printing technique or reading machine.

Datamatrix codes; Readability; Multi-colored codes; Error-correction system.

nije evidentirano