The ability to efficiently identify objects with a high degree of confidence is vital for many reasons, whether to prevent counterfeiting or to distinguish outwardly similar items. One common method is the use of tags, such as barcodes or fluorescent paint. However the use of single identification techniques can have significant drawbacks, as they can be more readily counterfeited, or the tags may degrade over time.
What it does
We have developed a more robust 2-component identification system that uses both a visual and an x-ray fluorescence marker. The tags are long-lived and both application and recognition can be fully automated. The tags can also be made invisible, further improving security.
How it works
Our method (shown schematically in Fig. 1) combines a tag readable via x-ray fluorescence (XRF) with visual identification of a separate part of the object (this could be a bar-code, shape, defect, etc.). The information from these two identifiers is processed and checked against a database. The XRF read-out provides highly specific chemical information of the tag, which can be applied, for example, as an invisible paint of nano-particles onto part of the object. The visual identification provides an additional level of certainty that the object is correctly identified. If set up in that way, the visual system could also be used for monitoring of e.g. defect propagation.
Fig. 1: A Diagram showing the system for object identification, using a combination of XRF and visual identification. The object (100) has a visual identification feature (104) and an XRF tag (102). These can be detected by the system using separate detectors (14) and (20). The result of the detections can be used to automatically identify the object.