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Owing to the advantages of cost-effectiveness, compactness, and the avoidance of complicated camera synchronization, single-camera three-dimensional (3D) digital image correlation (DIC) techniques have gained increasing attention for deformation measurement of materials and structures. In the traditional single-camera 3D-DIC system, the left and right view images can be recorded by a single camera using diffraction grating, a bi-prism, or a set of planar mirrors. To further improve the measurement accuracy of single-camera 3D-DIC, this paper introduces a single-camera four-view imaging technique by installing a pyramidal prism in front of the camera. The 3D reconstruction of the measured points before and after deformation is realized with eight governing equations induced by four views, and the strong geometric constraints of four views can help to improve the measurement accuracy. A static experiment, a rigid body translation experiment, and a four-point bending experiment show that the proposed single-camera 3D-DIC method can achieve higher measurement accuracy than the dual-view single-camera 3D-DIC techniques and that the single-camera 3D-DIC method has advantages in reducing both random error and systematic error. [ABSTRACT FROM AUTHOR]

To solve the real-time transmission problem of displacement fields in digital image correlation, two compression coding algorithms based on a discrete cosine transform (DCT) and discrete wavelet transform (DWT) are proposed. Based on the Joint Photographic Experts Group (JPEG) and JPEG 2000 standards, new non-integer and integer quantizations are proposed in the quantization procedure of compression algorithms. Displacement fields from real experiments were used to evaluate the compression ratio and computational time of the algorithm. The results show that the compression ratios of the DCT-based algorithm are mostly below 10%, which are much less than that of the DWT-based algorithm, and the computational speed is also significantly higher than that of the latter. These findings prove the algorithm's effectiveness in real-time displacement field wireless transmission. [ABSTRACT FROM AUTHOR]