A digital equivalent data system (DEDS) is a system for identifying objects by means of the x-ray fluorescence (XRF) spectra of labeling elements that are encased in or deposited on the objects. As such, a DEDS is a revolutionary new major subsystem of an XRF system. A DEDS embodies the means for converting the spectral data output of an XRF scanner to an ASCII alphanumeric or barcode label that can be used to identify (or verify the assumed or apparent identity of) an XRF-scanned object.

The Coordinates of Each Peak in an XRF Spectrum of a label would contribute information on the contents of the label: The horizontal coordinate would indicate a photon energy and, hence, the identity of an element; the vertical coordinate would indicate the spectral intensity and, hence, the abundance of the element.

A typical XRF spectrum of interest contains peaks at photon energies associated with specific elements on the Periodic Table (see figure). The height of each spectral peak above the local background spectral intensity is proportional to the relative abundance of the corresponding element. Alphanumeric values are assigned to the relative abundances of the elements. Hence, if an object contained labeling elements in suitably chosen proportions, an alphanumeric representation of the object could be extracted from its XRF spectrum. The mixture of labeling elements and for reading the XRF spectrum would be compatible with one of the labeling conventions now used for bar codes and binary matrix patterns (essentially, two-dimensional bar codes that resemble checkerboards). A further benefit of such compatibility is that it would enable the conversion of the XRF spectral output to a bar or matrix-coded label, if needed. In short, a process previously used only for material composition analysis has been reapplied to the world of identification. This new level of verification is now being used for “authentication.”

The DEDS as described thus far would be used to process XRF spectral data output only. In one of several alternatives, an object could be labeled with both a conventional bar or matrix code and an XRF tag, so that the XRF tag could be used to provide redundant, additional, or confirmatory information. In that case, the DEDS would analyze the XRF tag and convert the readings to alphanumeric data in a recognized format. In yet another alternative, the XRF scanner would be used to acquire an XRF spectrum of not only the XRF tag but also the substrate material surrounding the tag. In that case, the spectral data output from the substrate would constitute an additional set of data that could be combined with the XRF label data and the bar-code or matrix readout to obtain an alphanumeric label unique to the labeled object or to the class that it represents.

Authentication is the natural evolution of the identification process as security technologies are combined with it. The XRF DEDS provides a unique set of methods to determine if an object is genuine. The respective sets of information cannot be duplicated and answers the question “is that the original object.”

Authentication using XRF DEDS is expected to have no negative impact on existing networks as its conversion is in ASCII format, and convertible to bar code or other symbology formats. In fact it is expected to simply “fit in” with other members of the identification technology family. It is intended as a process to eliminate counterfeits and knock-offs, enabling the routine data collection in the downstream process using bar codes and matrix codes to be much more secure. Finally, it is expected to find its way into the courtroom, having the unique insight as to which object is genuine and which is not. Authentication using XRF DEDS may well be the next-generation expert witness in product liability cases.

This work was done by Harry F. Schramm of Marshall Space Flight Center and Bruce Kaiser of Keymaster Technologies, Inc. For further information, contact Sammy Nabors, MSFC Commercialization Assistance Lead, at This email address is being protected from spambots. You need JavaScript enabled to view it. .

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Keymaster Technologies, Inc.
415 N. Quay Street, Suite 1
Kennewick, WA 99336

Refer to MFS-31886, volume and number of this NASA Tech Briefs issue, and the page number.


NASA Tech Briefs Magazine

This article first appeared in the May, 2005 issue of NASA Tech Briefs Magazine.

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