Abstract

In tensile machines to measure the change in length of the specimen during the stress, most time extensometer and various contact methods and tools, such as strain gauges are used, but these methods have limitations and low accuracy that cause unexpected and different results from the theoretical values for the strain. In this paper, to address this shortcoming and improve strain measurement, a non-contact method using image processing techniques in the MATLAB environment is introduced. for this purpose after capturing a move of tensile test and converting that in to some high quality pictures and using image processing we put some pattern in the first image and with using a special algorithm with name of Digital Image Correlation (DIC) detect that patterns until the last image then we can use of displacement algorithm and calculate change in the specimen’s length and after that we can also have “Strain” with using these values.