Abstract
The advantages of full-field strain measurement are non-contact and wide area. However, its stability and higher resolution are necessary for a practical purpose in engineering application. Accordingly, we should reduce all of errors from shutter mechanism, mechanical vibration, flicker noise caused by light condition and so on, otherwise it is difficult to ensure the accuracy of strain less than 0.001. In this paper, we propose the definition of the resolution of strain measurement and how to obtain the higher resolution by Integrated Dot Centroid Tracking Method. The resolution is defined by standard deviation of the centroid position and can be described by three parameters, which are number of images, dot diameter and distance between each dot. We measure the standard deviation can be computed by the proposed formula. For the validation, we obtained the five standard deviations using averages of nine dots obtained from 5,000 data and infer the resolution using the interpolated standard deviations. We discuss the accuracy of the proposed formula by simple tensile test and the validity of the resolution.
