| 摘要 |
A first wave of a glass breaking sound has a sharp peak due to an impact sound and thereafter it attenuates rapidly. The attenuating characteristics of the first wave is measured with an attenuating time or a magnitude of attenuation thereof so that whether or not glass breaking has occurred is determined. Since an original waveform obtained by a microphone includes noise, low frequency components are eliminated by a high pass filter. The characteristics of the first wave of the glass breaking sound is almost stable. Therefore, by detecting the characteristics from the first wave, the glass breaking can be detected without errors. Further, since the glass breaking is detected by attenuation of the first wave, the detection can be carried out quickly. |
