Detection of hidden objects by terahertz heterodyne laser imaging
AssigneeCoherent, Inc.
InventorEric Mueller
Life of this patent
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Abstract
A THz-frequency heterodyne imaging method is used to remotely detect objects concealed in or under a person's clothing. One THz-frequency beam is scanned over a person being examined. A portion of the beam penetrates the persons clothing and is reflected by an object concealed under the person's clothing. The reflected portion the beam is mixed with another beam of THz-frequency radiation having a different frequency to provide a signal having an intermediate frequency (IF) including image data representative of the concealed object.
Claims29
A method of detecting objects or substances concealed in or under a person's clothing comprising;
- scanning a first beam of THz-frequency radiation, from a first source thereof over the person whereby a portion of said first beam penetrates the persons clothing and is reflected from an object or substance concealed under the person's clothing;
- and
- mixing the reflected portion of said first beam with THz-frequency radiation from a second source thereof to provide a signal having an intermediate frequency (IF) and including image data representative of the concealed object or substance.
A method of detecting objects or substances concealed in or under a person's clothing comprising;
- scanning a first beam of THz-frequency radiation over a person, said first beam having a frequency tuneable over a predetermined range, from a first source thereof;
- periodically sweeping the frequency of said first beam through said predetermined range while scanning said first beam of THz-frequency radiation over the person whereby a portion of said first beam penetrates the persons clothing and is reflected an object or substance concealed under the person's clothing;
- and
- mixing the reflected portion of said first beam with THz-frequency radiation from a second source thereof to provide a signal having an intermediate frequency (IF) and including image data representative of the concealed object or substance.
A method of generating an image of a concealed object comprising the steps of:
- generating a first laser beam of narrowband radiation having first THz-frequency;
- generating a second laser beam of narrowband radiation having second reference THz-frequency;
- scanning the first laser beam over the target;
- collecting the laser radiation reflected from the target;
- mixing the collected reflected radiation with the reference radiation;
- processing the mixed radiations to extract an image signal;
- and
- displaying the image signal in a manner to reveal a concealed object.
Dependencies are inferred from the claim text.