Development of Optimal Speckle Patterns Through Digital Image Correlation Technique

Abstract

Digital image correlation plays a dynamic role in aerospace industry due to its comparative affluence of application and developments in digital cameras has been the supporting these technologies for this process and full-field optics have played the major tactic. This technique was initially developed in 1980s and various researchers has investigated this procedure in structural analysis of specimens. It is generally used for experimental measurement probably for surface displacement investigation in solid mechanics. The objective of this technique suggests the prospect to control full-field displacement at the surface of specimen during any process of loading. It is designed for ideal usage of the method the objective here is covered with speckle pattern. In this paper, the effectiveness of a random speckle image and its outcome on the measured in full-field displacement with reference to the facet size is optimized for this study each speckle image gets transformed numerically and deformation are measured with open source DIC software.initially the optimal patterns are developed through MATLAB software and gray scaling and noise addition are done to the images to smoothen The calculated displacements are equated and its investigated that the measure of speckle image and its spectral property along with the measure of the used pixel subset impacts accurateness of the calculated displacements.. tensile loading is added to the pre-processed patterns and through high-speed camera the patterns are captured and post-processing of structural analysis is done in GOM correlate software and strain rate are calculated accordingly to increasing rate of strain was observed with different patterns through which the effectiveness of speckle patterns was observed. Characteristics of speckle patterns were also observed and its spectral density was also monitored and it’s concluded that maximum deformation occurs when spectral density was increased to optimize the speckle patterns.