Use of modulated reference wave in electronic speckle pattern interferometry
O J Lokberg; K Hogmoen; O J Lokberg; Dept. of Phys., Norwegian Inst. of Technol., Trondheim, Norway; K Hogmoen; Dept. of Phys., Norwegian Inst. of Technol., Trondheim, Norway
Журнал:
Journal of Physics E: Scientific Instruments
Дата:
1976-10-01
Аннотация:
The amplitude range for vibration measurement by time-average recording in electronic speckle pattern interferometry (ESPI) has been extended by sinusoidal phase modulation of the reference wave. The technique is, in part, similar to the reference wave modulation technique known from holography. The low resolution of the ESPI system results in a greater need for an extension of the measuring range. In addition, the technique is more convenient to use combined with ESPI, because of the instantaneous presentation of interferograms by this system. The modulation technique also provides information about the vibration phase. Fringe patterns illustrating applications of this technique are presented.
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