Systems and methods provide for a document fraud detection system for identifying fraudulent documents. The document fraud detection system can include up to three steps of fraud detection, where if the document fails any of the three steps, the document can be flagged for further review. In another embodiment, the document fraud detection system can score each of the three tests, where the scores represent the likelihood that the document is fraudulent. If the combined score satisfies a predetermined criterion, the document can be flagged as potentially fraudulent. The three tests can include analyzing a scanned image of the document and comparing to other similar documents to determine if there have been any alterations. The second test can compare indents to previous documents, and the third test can analyze chemical and biometric factors that may indicate whether the document has been altered.

In order to perform high-accuracy authentication of a forgery prevention medium having a forgery prevention structure, the forgery prevention structure provided in or on the medium for performing authentication of the medium is formed so as to include a mixed area with a plurality of kinds of resonator structures each of which resonates with a terahertz electromagnetic wave having a different polarization direction.

An electromagnetic wave detection apparatus easily detects characteristics of an object with respect to terahertz electromagnetic waves having different polarization directions. The apparatus includes: a first transceiver that transmits a first terahertz electromagnetic wave having a first polarization direction to a medium; a second transceiver that transmits a second terahertz electromagnetic wave having a second polarization direction different from the first polarization direction to the medium; and circuitry that detects a characteristic of the medium from portions of the first terahertz electromagnetic wave and the second terahertz electromagnetic wave that pass through the medium and are received by the first transceiver and the second transceiver respectively.

An electromagnetic wave detection apparatus easily detects characteristics of an object with respect to terahertz electromagnetic waves having different polarization directions. The apparatus includes: a first transceiver that transmits a first terahertz electromagnetic wave having a first polarization direction to a medium; a second transceiver that transmits a second terahertz electromagnetic wave having a second polarization direction different from the first polarization direction to the medium; and circuitry that detects a characteristic of the medium from portions of the first terahertz electromagnetic wave and the second terahertz electromagnetic wave that pass through the medium and are received by the first transceiver and the second transceiver respectively.

In order to perform high-accuracy authentication of a forgery prevention medium having a forgery prevention structure, a forgery prevention structure provided in or on a medium for performing authentication of the medium includes: an anisotropic resonator that resonates in response to being irradiated with a first terahertz electromagnetic wave at a first frequency, a transmissivity of the first terahertz electromagnetic wave changes with a polarization direction of the first terahertz electromagnetic wave, and an isotropic resonator that resonates in response to be irradiated with a second terahertz electromagnetic wave at a second frequency, a transmissivity of the second terahertz electromagnetic wave does not change with a polarization direction of the second terahertz electromagnetic wave.

In order to perform high-accuracy authentication of a forgery prevention medium having a forgery prevention structure, a forgery prevention structure provided in or on a medium for performing authentication of the medium includes: an anisotropic resonator that resonates in response to being irradiated with a first terahertz electromagnetic wave at a first frequency, a transmissivity of the first terahertz electromagnetic wave changes with a polarization direction of the first terahertz electromagnetic wave, and an isotropic resonator that resonates in response to be irradiated with a second terahertz electromagnetic wave at a second frequency, a transmissivity of the second terahertz electromagnetic wave does not change with a polarization direction of the second terahertz electromagnetic wave.

A system and method for authenticating an additively manufactured component is provided. The method includes locating an identifying region of the component that includes localized density variations that define a component identifier. The method further includes interrogating the identifying region of the component using a scanning device such as an x-ray computed tomography device to obtain the component identifier. The method further includes obtaining a reference identifier from a database, comparing the component identifier to the reference identifier, and determining that the component is authentic if the component identifier matches the reference identifier.

A system and method for authenticating an additively manufactured component is provided. The method includes locating an identifying region of the component that includes localized density variations that define a component identifier. The method further includes interrogating the identifying region of the component using a scanning device such as an x-ray computed tomography device to obtain the component identifier. The method further includes obtaining a reference identifier from a database, comparing the component identifier to the reference identifier, and determining that the component is authentic if the component identifier matches the reference identifier.

An apparatus and a corresponding method for checking value documents, involves at least one first sensor configured to detect electromagnetic radiation reflected and/or transmitted by a value document and to convert the radiation into corresponding first sensor signals. At least one second sensor is configured to detect sound waves reflected and/or transmitted by the value document and to convert the sound waves into corresponding second sensor signals, and an evaluation device configured to determine a first area value which characterizes a first area of the value document on the basis of the first sensor signals, to determine a second area value which characterizes a second area of the value document on the basis of the second sensor signals, and to infer a possible identification marking of the value document with a marking ink on the basis of the first and second area value.

An apparatus and a corresponding method for checking value documents, involves at least one first sensor configured to detect electromagnetic radiation reflected and/or transmitted by a value document and to convert the radiation into corresponding first sensor signals. At least one second sensor is configured to detect sound waves reflected and/or transmitted by the value document and to convert the sound waves into corresponding second sensor signals, and an evaluation device configured to determine a first area value which characterizes a first area of the value document on the basis of the first sensor signals, to determine a second area value which characterizes a second area of the value document on the basis of the second sensor signals, and to infer a possible identification marking of the value document with a marking ink on the basis of the first and second area value.