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US 7,114,393 B2Granted
Method and apparatus for laser vibrometry
AssigneeBAE SYSTEMS plc
InventorRoger Martin Langdon
Life of this patent
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AssigneeBAE SYSTEMS plc
InventorRoger Martin Langdon
Estimating the term…
Apparatus and method for identifying a remote target (7; 7a) is described. The remote target (6; 6a) is illuminated with radiation (5; 5a) generated by a laser (1; 1a) and the radiation scattered by the target (6; 6a) is modulated in phase by the surface (6; 6a) vibrations of the target (7; 7a). A portion of the scattered radiation is collected by multiple optical receivers (8, 9, 10; 8a, 9a, 10a) and demodulated by a phase demodulator to generate a signal proportional to the vibrational displacement of the remote target (7; 7a). The radiation scattered by the remote target (7; 7a) will also include laser ‘speckle’, generated when radiation is scattered by a rough solid surface. This speckle can generate errors in the signal demodulated, which can in turn cause identification errors. Apparatus is disclosed where the signals generated are substantially unaffected by laser speckle, improving the accuracy of remote target identification.
A laser vibrometer for identifying remote targets by detecting mechanical vibrations therein, said vibrometer having an array of coherent optical receivers for collecting a portion of laser light reflected by a remote target, each receiver providing an output, and signal processor means comprising an autocovariance processor having multiple inputs for combining said outputs of the receivers to produce a signal representative of the remote target and for removing laser speckle.
A laser vibrometer for identifying remote targets by detecting mechanical vibrations therein, said vibrometer having an array of coherent optical receivers for collecting a portion of laser light reflected by a remote target, each receiver providing an output, and signal processor means for combining said outputs of the receivers to produce a signal representative of the remote target and for removing laser speckle;
A method of detecting the mechanical vibrations of a remote target using a laser vibrometer, comprising the steps of:
Dependencies are inferred from the claim text.