“…Residual stress is the stress within a material which is generated during the process of machining, alloying and jointing that can reduce the rigidity and stability of a component in service; hence it is vitally important to understand the state of residual stress distribution. The measurement of residual stress started in the 1930s and included destructive methods, such as the hole-drilling method, the cutting method and the layer stripping method, and non-destructive methods, such as x-ray diffraction, ultrasonics, magnetics and neutron diffraction [2][3][4][5][6]. Destructive methods are often combined with other methods for deformation measurement, such as the strain gauge technique, or optical methods, such as the moiré method or geometric phase analysis (GPA) methods [7][8][9], giving a wide range of applications in residual stress measurement.…”