2009 Volume 11 Issue 2 Pages 53-62
The previous study has been reported that the use of a room was visualized by using the number of the maximum and minimum date of the filtered ordinary noise with a passband of one octave. Because acoustic information is complementary to a blind spot, the measurement of the ordinary noise, respecting privacy, may provide an index of principal events in a common sight. Our present study has aimed at identifying whether the number of extrema could reflect the harmonics of noise originated in passersby, who were concurrently sensed by a pyroelectric infrared detector. While approximate seventy percent of 990 events per week related to infrared rays were reported by the conventional sound pressure level, which was hard to be normalized in a day, due to the large amplitude of an unexpected crashing sound, ninety percent of the events were detected by the number of extrema with a bandwidth of 2,560-5,120Hz, suggesting an unique security application in order to save time for the editing process of video archives.
