Vibration imagery of remote objects
Reinhard R. Ebert, Peter Lutzmann · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2002
Laser vibrometry based on coherent detection technique allows to measure vibration characteristics of objects, based on its high Doppler resolution. Point targets were measured up to 40 km under medium turbluence conditions. Specifically vibration imaging offers an extensive potential for short-range civil applications and for long-range target classification and identification. For short range applications (up to few meters distance) laser vibrometry is used for investigating and testing of all kind of mechanical structures with respect to their vibration characteristics. Laser-Doppler based acoustic-to-seismic detection of buried mines shows a potential of this attractive technique at short range, mostly based on λ = 632 nm (HeNe laser). At longer ranges, the wavelengths of λ = 10.6 μm (CO2 laser) and λ = 1.5 μm (erbium fiber laser) are of interest, because of laser safety and better beam propagation through the atmosphere. Examples of the vibrometry technique with and without spatial resolution capability are shown here.