Patent ID: 9536400
Date: 2017-01-03
CPC Classifications: G08B,H04N

Claim:
1. An abnormality detection device comprising: a frequency analyzer for calculating by a frequency analysis a specific frequency component included in an alarm sound to be detected; a similarity detector for calculating a degree of similarity between two separate time domain change patterns in a signal waveform indicating a time domain change of the specific frequency component in an output of the frequency analyzer, wherein for each of the two separate time domain change patterns the analysis of the frequency analyzer comprises a calculated degree of similarity between the time domain change pattern of a signal waveform of a specific period and the time domain change pattern of a signal waveform of a former period to the specific period; and a judgment part for judging an existence of the alarm sound by a magnitude of the degree of similarity; wherein said device comprises an equation to calculate a specific frequency component of a sequential alarm sound using discrete Fourier transform.