“…For different scale lengths, different speckle patterns should be used [ 21 ]. DIC was used to measure the macrostrain of a bulk material, and the Young’s modulus of the bulk material was successfully determined from the obtained stress–strain curve [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Recently, research was carried out to determine appropriate experimental conditions, such as subset size and speckle, for micro- and mesoscale DIC [ 20 , 21 , 22 , 23 , 24 ].…”