In this paper, we describe some new sound field measurement methods by using laser Doppler vibrometer (LDV). By Irradiating the reflection wall with a laser, we can observe the light velocity change that is caused by the refractive index change from the change in air density. It means that it is possible to observe the change of the sound pressure.We measured a sound field projection on a 2-D plane using a scanning laser Doppler vibrometer (SVM) which can visualize a sound field. And we made a 3-D sound field reconstruction from some 2-D laser projections based on the computed tomography (CT) techniques. We made the reconstruction image for the sound field near the loudspeaker or in the room.

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