Meta-lens digital image correlation

With the same level of measurement accuracy, more portable and miniaturized measurement systems will have greater advantages, providing users with more flexible and convenient measurement solutions. Here, we introduce a new type of digital image correlation (DIC) system that incorporates a binocular meta-lens, featuring a simple and compact configuration. Meta-lens is one of the promising flat optical imaging devices that are ultra-thin, customizable, and well-suited for use in confined spaces. We evaluated this binocular meta-lens based DIC(BM-DIC) system through classic in-plane and out-of-plane translation tests, followed by a bending test on a helicopter wing model to capture 3D displacement and deformation fields. For in-plane translations, the system achieved high precision with a standard deviation (σ) below 2 µm. Despite a small baseline of 4 mm, the system maintained a σ of approximately 32 µm for out-of-plane translations. Comparative analysis with conventional dual-camera stereo DIC systems showed that the BM-DIC system maintains an acceptable relative error margin of about 1% in measured strain fields despite a 75-fold reduction in baseline length. This research demonstrates the integration of DIC techniques with advanced meta-lens technology, indicating substantial potential to enhance the capabilities of DIC technology in experimental solid mechanics.