Millimeter wave imaging as a tool for traceability and identification of tattooed markers in leather

In this work, an innovative solution for traceability of leather throughout the leather manufacturing process is presented. The proposed solution is founded on the use of high-resolution millimeter wave synthetic aperture radar (SAR) imaging technique that can be effectively used to sense the presence of sub-surface identification markers inserted (tattooed) into the hides to be tracked. This proposed imaging solution satisfies all the major requirements of the considered applications; in fact, the identification markers do not affect the characteristics of the finished leather product. The proposed imaging system is also completely noninvasive, and fully scalable for industrial applications. For validating the proposed technique, different leather samples were tattooed with conductive ink, and the presence of the markers was then sensed through SAR millimeter wave images. For comparison purposes, several X-ray scans were also obtained from the leather samples.