A study on implementation of active localization system using a microphone array and a loudspeaker in a small room

摘要

Active localization system using a microphone array and a loudspeaker is developed to detecting the position of a silent intruder in building security system. Proposed system has a similar concept with ultrasound system in terms of active system. Ultrasound imaging is obtained by transmittance and reception of excitation signals, and acoustic imaging produced by the active localization system is obtained as a transmitter, a loudspeaker, and a receiver, a microphone array. If proposed approach is considered about getting the spatial information in the control domain, active localization system estimates the position information using only a line microphone array. However, this proposed system is assessed in an anechoic chamber. In this paper, the active localization system is dealt with in reverberant environment. If this system is applied in a relative large room, the results of acoustic imaging are reasonable, but acoustic imaging in a small room possibly becomes bad results because room effects in a small room make complex distributed pressure of sound field. Therefore, inverse filtering with regularization is employed to suppress the room effects. To design the inverse filter, simplified configuration is established using medium density fibreboard (MDF) in an anechoic chamber. The measured signals from this setup are applied to inverse filtering, and room effects are reduced, while the effects of a PVC pipe are increased.