Determining Sound Source Orientation from Source Directivity and Multi-microphone Recordings

Hallam

2009 Advanced Technologies for Enhanced Quality of Life

2009

Self Cite

We present a method to estimate the orientation of a directional sound source and experimental results illustrating its performances. The method requires recordings captured by an array of microphones at known positions with respect to the source as well as the source directivity. Experiments have been performed in an ordinary environment by using a Polaroid transducer as the sound source emitting a broadband signal in the ultrasonic range. Such an acoustic signal has similar structure to those used by bats to echolocate. Results show that method is precise provided that the source directivity ensonifies the microphone array sufficiently. Further developments of the method, and its ultimate application to the reconstruction of emitted bat calls from remote recordings, are discussed.

Section: Discussionmentioning

confidence: 88%

“…The method presented in this paper has also been tested in simulation on a PC, reported in [2], by using only computational models instead of real sound signals collected by microphones. The analytical directivity (8) was used for the Polaroid transducer as source and microphones were placed at unit distance.…”

Section: Discussionmentioning

confidence: 99%

Determining Sound Source Orientation from Analytical Source Directivity and Real Multi-Microphone Recordings

Hallam

2009 Advanced Technologies for Enhanced Quality of Life

2009

Self Cite

“…Expression (3) for e f can be substituted into E(e f , R) so that it depends only on the variable R, see [3]- [5]. The true rotation of the source should correspond to the rotation minimizing E(R), that is,…”

Section: Analytical Solutionmentioning

confidence: 99%

“…An error function E(e f , R) is built up from (2), see [3]- [5], as function of rotation R the source assumes. Function E is linear in the unknown call spectrum e f and is minimized for a given rotation when e f has the following expression:…”

Section: Analytical Solutionmentioning

confidence: 99%

See 1 more Smart Citation

Reconstructing the Acoustic Signal of a Sound Source: What Did the Bat Say?

Hallam

Lecture Notes in Computer Science

2010

Self Cite

Abstract. When attempting to model and understand bat biosonar behaviour, it would be very useful to know exactly what calls the bat emits, that is, what it really says, in the course of its exploration of the world. Calls could be recorded by miniature radio microphone, but such systems are complex and not all bats are sufficiently strong to carry one. In this paper we describe a technique for reconstructing the actual emitted signal of a bat using recordings collected by an array of remote microphones. The theory of the technique is described, experimental results with laboratory-recorded data (for which ground truth is available) are presented, and the performance of the method is discussed.

A method for estimating the orientation of a directional sound source from source directivity and multi-microphone recordings: Principles and application

Jakobsen

The Journal of the Acoustical Society of America

et al. 2011

Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in the ultrasonic range, in this application) that is recorded by microphones whose position with respect to source is known. An analytical method to process the recorded signals and estimate source orientation is developed in this paper. Experiments testing method performance in estimating source orientation were performed both in a laboratory environment with a Polaroid transducer as source and in a flight room with a Myotis daubentonii bat. In the first case, results showed the estimation method to be accurate and pointed out its limitations. The latter case is significant as an example biological application of the method for extracting behavioral features from bats; results are compared with alternative calculations based on microphone root-mean-square (rms)-pressure values.