Model-Based 3-D Vibration Measurement Using Stereo High-Frame-Rate Images

Vibration measurement is crucial for assessing the durability and reliability of structures and products. While 3-D digital image correlation (DIC) methods based on stereo image analysis are widely used to visualize 3-D vibration distributions, their performance significantly degrades on weakly textured surfaces due to their reliance on substantial textures or artificial patterns for stereo correspondence. This dependence limits robustness, accuracy, and processing efficiency. To overcome these limitations, we propose a model-based 3-D-DIC method that enables robust and accurate measurement of 3-D vibration distributions with minimal dependence on surface patterns. Using semirigid 3-D shape priors, our method projects model points onto stereo images and reconstructs 3-D vibrations through the triangulation of 2-D-DIC displacements. The projection strategy eliminates the need for complex stereo correspondence, thereby improving the processing efficiency. A cuboid experiment with 0–4-mm-depth movements demonstrated an accuracy of $34~\mu $ m under low-contrast conditions, outperforming conventional 3-D-DIC methods without shape priors. Dynamic measurement performance was assessed using a repetitive-texture metal plate vibrating at various frequencies, where a 450-Hz vibration with a peak amplitude below $20~\mu $ m was detected with an error under $3~\mu $ m. Our method precisely visualizes 3-D vibration distributions at 40 and 100 Hz on a low-texture PC stereo speaker. These results demonstrate that our method provides a promising solution for the accurate, robust, and efficient measurement and analysis of 3-D vibrations in weakly patterned objects.