QR code recognition of magnetically printed features


The research institute INNOVENT has developed a system which is able to visualize hidden QR Codes printed with magnetizable ink. Further information can be found behind the following link


Ticket Reader for reading magnetic information in the field of ticketing

The Ticket Reader is a specially developed test machine for the detection of magnetic features on print media in the field of ticketing. Based on the magneto-optical sensor technology, the method allows for a quick check of magnetic security codes.

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The evaluation software is based on a QR-Code recognition algorithm which is a central core of the NOVA framework at AXON Innovations. As shown in the following figure, the source image is not suitable for standard QR Code recognition. The original magneto-optical image is processed by a specially developed filter mechanism and recognition algorithm. The most modern methods were used, even machine learning was not neglected.

left: Source image as enlargement / small images: extracts from the processing chain

At the end of the processing chain the magnetically printed QR Code can be recognized and digitized. Here it is particularly important that the image capture processing only takes a few seconds so that the method can be used in the ticketing area. The programming language C++ serves as a basis.

If the magnetic characteristics are well designed, a high reproducibility of the readout process is guaranteed (> 95% readout reliability). The magneto-optically readable feature can also be hidden within certain limits and thus designed to be optically invisible.