Acoustic Source Localisation In An Urban Environment Using Early Reflection Information
Invited paper
Audio Lab
Monday 1 june, 2015, 11:00 - 11:20
0.3 Copenhagen (49)
Abstract:
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.