Patent ID: 11878696
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC B  G  H | IPC B  G  H

Claim 5:
6. An abnormality detection method comprising:
acquiring an acoustic signal generated during passage of a vehicle on a road by a vibration acquisition unit;
converting the acquired acoustic signal into a frequency domain signal by a frequency domain conversion unit;
determining whether there is unexpectedness at each predetermined frequency using the frequency domain signal by an unexpectedness determination unit, wherein the unexpectedness is based at least on a short-time average level and a long-time average level of a spectrum of each frequency and a threshold set in advance; and
determining whether there is an abnormality in the road based on the number of frequencies at which it is determined that there is the unexpectedness by an abnormality determination unit.