LAUSR

A volumetric ultrasound tomography (UST) system and method are established for industrial process applications. A two-plane ring-array UST system is developed for 3-D imaging of the process under test. Such a 3-D system allows capturing axial variations, which is not possible in 2-D or 2.5-D imaging. A ray-voxel intersection method is used to create the sensitivity matrix needed for the 3-D or 4-D image reconstruction. Acquiring and processing time series data lead to 4-D imaging, generating dynamical volumetric image by using a time correlative total variation (TV) algorithm. The 3-D forward model using the ray propagation model offers a computationally efficient tool for modeling the measurement process in UST and is used for image reconstruction. In combination with the advanced 4-D TV algorithm, high-quality information is gained from time and space. At first, the 3-D imaging methodology was tested and verified using static objects. Second, 4-D imaging was investigated by using a moving rod in an experimental tank. The system was then implanted to carry out dynamical process monitoring, imaging 4-D crystallization process. Finally, the results are evaluated using quantitative image evaluation in the 3-D mode and process dynamics in the 4-D imaging mode.