Real-time audio surveillance system for PTZ camera

In this paper, we propose an audio surveillance system to detect and localize dangerous sound in real-time so as to be able to direct a PTZ camera to catch a snapshot image about the location of sound source instantly. The proposed audio surveillance system firstly detects foreground sound based on adaptive Gaussian mixture background sound model, and classifies it into one of pre-trained classes of foreground sounds based on GMM model. Next, it decides whether it belongs to dangerous class group or not. If it does, then a sound source localization algorithm based on Dual delay-line algorithm is applied to localize the sound source. Finally, the proposed system uses the sound source location information to pan and tilt the PTZ camera towards the orientation of the dangerous sound source, and take a snapshot against over the sound source region. Experiment results show that the proposed system can detect foreground sound stably and recognize dangerous sounds with a precision of 79% while the sound source localization can estimate orientation of the sound source with acceptably small error.