Real time acoustic source localization of emergency signals

Abstract

In this paper, we have chronicled the development of sound localization system based on TDOA (Time Difference of Arrival). Acoustic Source Localization (ASL) is a technique used to track and locate the exact location of a sound source using an array of microphones. The concept of ASL uses sound signals captured from an array of microphones and they are processed using TDOA localization method to estimate the probable direction of sound source w.r.t to the microphone location. TDOA algorithm is a time delay estimation technique which estimates the time difference in the signal received at each microphone pair. These time delays obtained are then used in the Linear Least Squares (LSQR) Algorithm to estimate the source position w.r.t the microphone array. This system is implemented in real-time by using an on-board DSP processor TMS320C6748.

Design of a Compact Sound Localization Device on a Stand-Alone FPGA-Based Platform

“…Large implementations, with microphone arrays between 250 mm and 500 mm, can be found in several studies [14], [15], [17], [45]- [47]. In some other works [4], [5], [16], middle size arrays of around 200 mm were used. Only few papers present relatively small solutions.…”

“…An artificial system capable of localizing a sound source would be beneficial in many fields. For instance, autonomous devices, such as robots or unmanned aerial vehicles (UAV), could function more reliably outside controlled environments [4]. Autonomous robots could be used in search and rescue or disaster recovery operations, such as searching for earthquake victims, where locating an individual beyond field-of-vision by sound is critical.…”

“…Interaural Level Difference (ILD) focuses on difCopyright c 2016 The Institute of Electronics, Information and Communication Engineers ferences in sound energy level as a cue for localization, while Interaural Time Difference (ITD) corresponds to the Time-Difference of Arrival (TDoA) of sounds between the two ears. The latter is the most direct cue for estimating the direction of the sound source and is used in the majority of the implementations as the primarily localization cue [4], [9]- [16]. Utilizing TDoA does not impose so many restrictions to the structure of the system when compared to other methods, but obtaining the time difference from separate sound channels might be computationally expensive, making the achievement of a real-time system challenging.…”

“…On the other hand, systems utilizing ITD cues can be implemented with as few as two omnidirectional microphones, without any special physical setup. Some solutions, although not requiring any additional structures, present considerably large spacing of the microphones [4], [5], [11]. Beamforming based implementations require multi-microphone arrays with specific geometries and are notorious for their high computational complexity [17], [20].…”

Cooperative Improved Target Localization in harsh Environments using Direction of Arrival

“…This information is useful when the position of nodes is provided with needed accuracy. Finding the position of targets (Localization) in WSNs has attracted a lot of interest in emergency applications [4,5], traffic control [6,7], military affairs [8], civil [9] and so forth. Different methods are proposed for node localization in WSNs such as what proposed in [10][11][12].…”