Investigation of speckle displacement effects on speckle interferometry

摘要

In the experimental set-up for measuring temperature fields in fluid flows by using speckle interferometry (e.g. electronic speckle pattern interferometry or phase shift speckle interferometry), the part of the arrangement for the object light beam is just like a subjective speckle photographic system. Therefore, in general, speckle displacements are generated. The speckle displacements can change the intensity distribution of spatial speckle fields. As a result, the intensity distribution of a speckle interferogram is also changed. In this paper the effect of speckle displacements on the speckle interferometry is analyzed and discussed in detail. A physical model and mathematical treatment for the effect are proposed. Experimental results are shown. A method for elimination of the effect is provided. Using the provided method, the temperature measurement error of speckle interferometry can be reduced and the measurement accuracy can also be increased.