3D sound-source localization using triangulation-based methods

• Main Author: Lam, Alice
• Language: English
• Published: University of British Columbia 2017
• Online Access: http://hdl.handle.net/2429/63551

The localization of sound sources in a reverberant environment, such as a classroom or industrial workspace, is an essential first step toward noise control in these spaces. Many sound source localization techniques have been developed for use with microphone arrays. A common characteristic of these techniques is that they are able to provide the direction from which the sound is coming, but not the range (i.e. the distance between the source and receiver).This thesis presents two triangulation-based methods for localizing sound sources in 3D space, including range, using a small hemispherical microphone array. Practical issues with the hemispherical array, such as source resolution and operating frequency limitations, are discussed. The first method - direct triangulation - involves taking multiple sound field measurements at different locations in the room, and then using the combined output of all receivers to triangulate the source. Direct triangulation is conceptually simple and requires no a priori knowledge of the surrounding environment, but proves cumbersome as multiple array measurements are required - this also limits its application to steady-state noise sources. The second method - image source triangulation - requires only one measurement, instead taking into account the early specular reflections from the walls of the room to create "image receivers" from which the source location can be triangulated. Image source triangulation has the advantage of only requiring one measurement and may be more suited to small spaces such as meeting rooms. However, it relies on having accurate pre-knowledge of the room geometry in relation to the microphones. Both triangulation methods are evaluated using simulations and physical in-room measurements, and are shown to be able to localize simple monopole sources in reverberant rooms. === Applied Science, Faculty of === Mechanical Engineering, Department of === Graduate