Full-field deformation measurement of a large-rotation object using digital image correlation

Digital image correlation method is widely used in macro- and mesoscopic mechanical tests because of the advantages of non-contact, high precision, full field measurement, and simple experimental equipment. But it still has many shortcomings in theory and application. For example, the traditional DIC method has difficulty obtaining the desired result when the surface of the test object is rotated substantially or the deformation involves large rotation (i.e. measuring helicopter blade deformation dynamically). Some scholars argue that a rotation angle greater than 7° will not work with the DIC algorithm, and this phenomenon is called decorrelation [1-3]. The application of various nonlinear optimization algorithms greatly reduces the computation time of the DIC iteration process.