Acoustic Source Localization using Reflected Signals

Project Type: Student Project, Master/Diploma Thesis
Student: Rudolf Liepins

Description

For conventional localization systems, multipath propagation is considered a serious impairment, since it can bias distance estimates. However, if some knowledge of the surrounding environment is available, reflected signal paths can be effectively used for localization. In [1], this is done with audio signals and a microphone array at the receiver side. Our wireless group has done some similar work based on ultra-wideband signals, but with single antennas on both transmitter and receiver side [2].

The goal of this project/thesis is a combination of both methods. Using a loudspeaker as source and a single microphone as receiver, measurements should be performed in a representative environment. To start with, the environment used in [2] seems reasonable for comparison purposes. With these measurements, the delays of the reflected signal paths should be estimated. The obtained estimates for the path delays should be compared to the theoretical ones based on the known room geometry.

If performed as a master thesis, a suitable localization scheme based on the multipath delays should also be implemented. This can be based on the methods in [2] with possible extensions in the data association methods. This is an important part of the localization system, as the estimated path delays are not a priori matched to the reflections. Furthermore, the extension to an uncontrolled source, i.e. a real speaker, is an interesting possibility.

Your Tasks

  • Acoustic measurements in a representative (controlled) environment
  • Estimation of multipath delays in Matlab, performance evaluation
  • Implementation of a localization scheme with data association (thesis only)

Your Profile

  • Student of Audio Engineering or similar background
  • Basic Matlab skills

References

[1] Svaizer, P., Brutti, A. and Omologo, M.: "Use of reflected wavefronts for acoustic source localization with a line array", Joint Workshop on Hands-free Speech Communication and Microphone Arrays (HSCMA), 2011

[2] Meissner, P. and Witrisal, K.: "Multipath-Assisted Single-Anchor Indoor Localization in an Office Environment", 19th International Conference on Systems, Signals and Image Processing, IWSSIP 2012