Effect of digital filtering on the analysis of surface deformations using electronic speckle pattern interferometer

Abstract

Digital filtering is an essential part of electronic speckle pattern interferometer which is been used widely to study surface deformations. Raw speckle patterns needs digital filtering before it is used for further analysis. Many times multiple use of digital filtering leads to change in the quantitative information of surface under study. This paper reports effect of multiple usages of various digital filters on the calculated surface deformation values. Multiple usages of various digital filtering leads to loss in speckleness of the pattern indicating decrease in speckle noise and marginal and in some cases significant change in surface displacement values.