High-speed digital-image correlation method

Provided that the software and hardware equipment in a digital-image correlation method is unchanged, the only major factor affecting integer-pixel correlation computation precision and the integer-pixel processing time is the size of the computing window. The bigger the size of the computing window is, the more reliable the computation result is. However, a bigger computing window means longer processing time. For reduction of the integer-pixel processing time without affecting the reliability of the result, a two-step correlation computation method (which uses a small window and a big window in the correlation computation) is proposed. The experiment results confirm the validity of the new method, and the total processing time of this method can be approximately reduced to a twentieth of that of the traditional method.