Surface vibration can be very accurately measured using the non-contact Laser Doppler Vibrometry (LDV) method, where a point-by-point sampling of the structure's surface is performed and the vibration directly obtained. Alternatively, surface vibration can be reconstructed using acoustical holography methods like the Inverse Boundary Element Method (IBEM) and Planar Near-field Acoustical Holography (PNAH), which both are based on acoustical near-field measurements. In addition, both of the acoustical holography methods allow for estimation of acoustical surface quantities like sound pressure and sound intensity and can provide an acoustical source model that may be used in acoustical radiation studies. While IBEM enables the estimation of surface vibration on arbitrary geometries, the PNAH method provides vibration estimates in a plane close to the structure. For an experiment using a vibrating panel, the quality of the surface vibration reconstruction from the acoustical holography methods are assessed and compared to the results from using the LDV method. Good agreement is found in both spatial distribution and absolute vibration levels between the different non-contact methods.
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