Figure 2.

Sound detection. The top graph shows the original sound signal. In the bottom graph depicts σ_signal and the two baseline threshold lines in which thresh_peak = 10 and thresh_limits = 1.5. Point 2(a) indicates the first standard deviation larger than thresh_peak × σ_background. Points 2(b) and 2(c) are the points nearest to point 2(a) where σ_signal is smaller than thresh_limits × σ_background. The whole region between points 2(b) and 2(c) is a sound event. In the same way, the region between points 2(d) and 2(e) will be detected as a sound event.