Recognition of the Ambulance Siren Sound in Taiwan by the Longest Common Subsequence

This paper proposes a method to recognize the ambulance siren sound in Taiwan. Since the ambulance siren sound is composed by a high frequency and a low frequency signal, the sequence of the frequency change is used to be the feature of the sound. The input sound is divided into frames, and each frame is classified into high frequency or low frequency. The Longest Common Subsequence (LCS) is used to compare the arrangement of the frequencies in the frames. We use the results of LCS to recognize whether the sound comes from an ambulance. Real sounds are used to show the performance. According to the experimental results, the accuracy rate is 85%.