| 摘要 |
An apparatus for checking the authenticity of a security document (28). The security document (28) comprises a base material and in its volume particles having some electromagnetic properties which are substantially different from the corresponding electromagnetic properties of the base material. The apparatus comprises at least one emitter (18) for emitting near infrared or visible waves to the document (28), at least one detector (20) for detecting any of the emitted near infrared or visible waves reflected from the document (28) and means (30) for processing the detected near infrared or visible waves in order to differentiate the security document (28) from a document comprising electromagnetic particles or parts on its surface.
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