Direction measurement of a sound source in 3-D space utilizing unidirectional characteristics of microphone’s sensitivity{sup}+

摘要

This paper proposes the measurement principle of a sound source direction in the three-dimensional space. Such kind of differences like the transferring time, phase shift, and level of the sound wave are treated for the measurement in general. Our approach is to use the differences of sound levels by taking the advantage of unidirectional characteristics of the condenser microphone's sensitivity so that the direction is obtained by the simple signal processing. Basically the minimum number of the microphone set is four for composing a tetrapod arrangement. Formulation of the relations among the differences of the sound levels is shown. Also, the logical processing is introduced to remove the affect of the microphone's backside undesirable irregular sensitivity. The calculation procedure for determining the direction is extracted, and experimental results are shown to verify the validity of the measurement.