| 摘要 |
PROBLEM TO BE SOLVED: To quickly and precisely detect traffic accident sounds. SOLUTION: The waveform of a sound signal from a surrounding sound detecting device which is not shown by a figure is shaped by a waveform shaping circuit 40, and digitized by an analog to digital converter 45. The digitized signal is spectrum-operated arithmetically by a band spectrum operation means 21, and the difference between the present value of that spectrum level and the average value of past spectrum levels found by an averaging means 23 is found by a difference operation means 22, By comparing this value with a reference difference value from a reference difference value generation circuit 24 in a comparator circuit 25, a traffic accident sound can be detected precisely and quickly. By adapting a primary distinction system which does not use any time waveforms (raw waveforms) varying complicatedly, configuration becomes simple, and processing can be quickened. COPYRIGHT: (C)2004,JPO&NCIPI
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