Multi-sensor Stethoscope for chest sound localization

Abstract

This paper addresses the feasibility of using a multisensor system consisting of several stethoscope chest pieces for the localization of chest sounds. A signal processing algorithm called beamforming can combine multiple inputs to amplify sounds coming from a particular region inside the chest and attenuate all others. Beamforming can also be used for source localization; that is, determining from where a particular sound originated. These methods can provide a non-invasive and inexpensive acoustic image of the chest cavity for diagnostic and therapeutic purposes. This paper reviews methods for localizing a sound source using a microphone array. It describes a method comparing the delay between signals received at known microphone locations to determine the coordinates of the sound source. To illustrate this concept, we use a circular array of microphones in a free-field homogeneous medium and use delay-and-sum beamforming to combine the received signals. The challenges of applying this method to a non-homogeneous medium will also be discussed.