Title: Diffraction-Aware Sound Localization for a Non-Line-of-Sight Source,
Abstract: We present a novel sound localization algorithm for a non-line-of-sight
(NLOS) sound source in indoor environments. Our approach exploits the
diffraction properties of sound waves as they bend around a barrier or an
obstacle in the scene. We combine a ray tracing based sound propagation
algorithm with a Uniform Theory of Diffraction (UTD) model, which simulate
bending effects by placing a virtual sound source on a wedge in the
environment. We precompute the wedges of a reconstructed mesh of an indoor
scene and use them to generate diffraction acoustic rays to localize the 3D
position of the source. Our method identifies the convergence region of those
generated acoustic rays as the estimated source position based on a particle
filter. We have evaluated our algorithm in multiple scenarios consisting of a
static and dynamic NLOS sound source. In our tested cases, our approach can
localize a source position with an average accuracy error, 0.7m, measured by
the L2 distance between estimated and actual source locations in a 7m*7m*3m
room. Furthermore, we observe 37% to 130% improvement in accuracy over a
state-of-the-art localization method that does not model diffraction effects,
especially when a sound source is not visible to the robot.