| CPC G01H 9/004 (2013.01) | 2 Claims |
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1. A vibration detection apparatus using a time-domain reflection measurement method, comprising:
an optical tester that makes optical frequency multiplex pulses including a plurality of fundamental optical frequencies incident on an optical fiber and acquires a Rayleigh backscattered light intensity; and
a control arithmetic unit that executes causing the optical tester to perform preliminary measurement in which the fundamental optical frequencies are changed by a moving optical frequency for each of the optical frequency multiplex pulses and are incident on the optical fiber to acquire a Rayleigh backscattered light intensity,
detecting direction vectors having temporal changes in the Rayleigh backscattered light intensity with respect to the fundamental optical frequencies as elements for each point of the optical fiber on the basis of the Rayleigh backscattered light intensity acquired through the preliminary measurement, and statistically processing the direction vectors for each moving optical frequency to create an approximate direction vector, and
causing the optical tester to perform main measurement in which the optical frequency multiplex pulses of the plurality of fundamental optical frequencies are incident on the optical fiber, direction vectors having temporal changes in the Rayleigh backscattered light intensity with respect to the fundamental optical frequencies as elements are detected for each point of the optical fiber, and vibration is detected from inner products of the direction vectors and the approximate direction vector.
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