Structure parameter analysis and uncertainty evaluation for single-camera stereo-digital image correlation with a four-mirror adapter.

Increasing interest in the use of single-camera stereo-digital image correlation (stereo-DIC) with a four-mirror adapter for full-field three-dimensional shape, motion, and deformation measurements has led to an ongoing need for both the optimal design of an optical structure and predictions of the measurement uncertainties. In this study, to get a clear knowledge of the optical model of the four-mirror adapter-assisted single-camera stereo-DIC system and further facilitate an optimal design of the optical structure for specific measurement objects, comprehensive analyses of the structure parameters, e.g., the baseline distance and valid field of view of the virtual stereo-DIC system, are conducted. Based on the law of propagation of uncertainties, the influence of the structure parameters on the measurement uncertainty is assessed theoretically. The effectiveness and accuracy of these analyses are verified by calibrating the single-camera stereo-DIC system and measuring the displacements of a stationary planar plate.