Authenticity Verification of Articles Using a Database
First Claim
1. A method of scanning an article arranged in a reading volume, comprising:
- collecting a set of data points from intensity signals obtained when coherent light scatters from the reading volume, the set of data points comprising at least one data point relating to scatter from a first part of the reading volume and at least one data point relating to scatter from a second part of the reading volume;
determining a digital signature of the article by digitising the set of data points; and
determining a thumbnail digital signature of the article by digitising an amplitude part of a Fourier transform of the set of data points.
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Accused Products
Abstract
A digital signature is obtained by digitising a set of data points obtained by scanning a coherent beam over a paper, cardboard or other article, and measuring the scatter. A thumbnail digital signature is also determined by digitising an amplitude spectrum of a Fourier transform of the set of data points. A database of digital signatures and their thumbnails can thus be built up. The authenticity of an article can later be verified by re-scanning the article to determine its digital signature and thumbnail, and then searching the database for a match. Searching is done on the basis of the Fourier transform thumbnail to improve search speed. Speed is improved, since, in a pseudo-random bit sequence, any bit shift only affects the phase spectrum, and not the amplitude spectrum of a Fourier transform represented in polar coordinates. The amplitude spectrum stored in the thumbnail can therefore be matched without any knowledge of the unknown bit shift caused by registry errors between the original scan and the re-scan.
141 Citations
26 Claims
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1. A method of scanning an article arranged in a reading volume, comprising:
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collecting a set of data points from intensity signals obtained when coherent light scatters from the reading volume, the set of data points comprising at least one data point relating to scatter from a first part of the reading volume and at least one data point relating to scatter from a second part of the reading volume; determining a digital signature of the article by digitising the set of data points; and determining a thumbnail digital signature of the article by digitising an amplitude part of a Fourier transform of the set of data points. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 25)
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9. An apparatus for scanning an article arranged in a reading volume, comprising:
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a source for generating a coherent beam; a detector arrangement for collecting a set of data points from signals obtained when the coherent beam scatters from the reading volume, the set of data points comprising at least one data point relating to scatter from a first part of the reading volume and at least one data point relating to scatter from a second part of the reading volume; and a data acquisition and processing module operable to;
(i) determine a digital signature of the article by digitising the set of data points; and
(ii) determine a thumbnail digital signature of the article by digitising an amplitude part of a Fourier transform of the set of data points. - View Dependent Claims (10, 11, 12, 13, 26)
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14. A database comprising a plurality of records, each comprising:
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a digital signature of an article obtained by digitising a set of data points obtained from the article, the set of data points comprising at least one data point relating to scatter from a first point of the article and at least one data point relating to scatter from a second point of the article; and a thumbnail digital signature of the article obtained by digitising an amplitude part of a Fourier transform of the set of data points.
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- 15. The database of claim 32, wherein the data points are obtained from scattering of coherent light from the article.
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21-24. -24. (canceled)
Specification