Acoustic Source Localisation In An Urban Environment Using Early Reflection Information
Monday 1 june, 2015, 11:00 - 11:20
0.3 Copenhagen (49)
Acoustic source localisation is the use of recorded information to determine the point of origin of a given sound. Applications include military threat detection, forensic acoustics, and the study of urban acoustic environments. Acoustic Impulse Response (IR) recording is a method of capturing the acoustic properties of a space. Recent work recording spatial IRs in a semi-enclosed urban environment has shown early reflections to be a predominant acoustic feature, with the majority of directional information being present in the horizontal plane. This paper presents a source localisation algorithm for urban environments with dominant early reflections. Spatial Impulse Response Rendering analysis is used to extract reflection information from B-format impulse response measurements. Reverse ray-tracing is then used in combination with a 2D geometric representation of the environment to estimate the position of the sound source. Additional metrics such as reverberation time, coherence, and spectral analysis are used to refine the algorithm further. Results show the system to perform well given a sufficiently sparse environment, with an IR exhibiting prominent early reflections. When used for recordings made in an enclosed and highly reverberant environment, the localisation performance suffers as a result of less distinct early reflections.
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