Laser vibrometry system

 © Technisches Museum Wien, Photo: Peter Sedlaczek
Collection Area
Technical and Scientific Principles
Physical/Chemical Fundamentals
1990 - 1999
At the moment this object is not published in the museum.

Acoustic oscillations and vibrations can only rarely be seen with the naked eye. However, they can be made visible using a measuring device and a computer.

A laser vibrometer works in a similar way to the laser speed cameras used by the police: A laser beam is aimed at the object and the reflected light is analysed. Its properties change slightly due to the Doppler effect, as there is surface movement caused by the vibration. A computer connected to the measuring head registers these changes and combines them to form a vibration pattern. If the laser is moved over the surface in lines (scanning vibrometer), a vibration pattern of the entire body is obtained.

This image can even be animated using the computer. You can then see how the surface moves during vibration. This allows people to find out where in a car noise is produced through vibration, for example, or whether an eardrum is sufficiently mobile, or why the surface of paper in a paper-making machine has shiny areas due to off-centre smoothing rollers, etc. It can also be used for investigating the sound properties of musical instruments, as has often been the case in the Technisches Museum Wien (Vienna Technical Museum). 

Manufacturer: Polytech, Waldbrunn
Date of construction: 1993

Inv.Nr. 31276

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