Nolinear Reconstruction for Liquid-liquid Two-phase Medium Ultrasonic Tomography

摘要

Industrial Process Tomography possesses unique advantages in biphasic medium measurement and has received broad attention in the past decades. Aiming at the widely existed low contrast biphasic medium, this paper proposed a nonlinear Ultrasonic Transmission Tomography (UTT). Approach using continuous wave excitation. Considering the refraction effect at the biphasic interface, the reconstruction method with nonlinear forward problem and the improved Simultaneous Algebraic Reconstruction Technique (SART) is proposed with high reconstruction accuracy and reconstruction speed. The performance of the reconstruction is quantitatively compared with the state-of-art reconstruction algorithms, where the proposed method can reconstruct inclusions with their number, size and position clearly identified. Quantitatively, the average Relative Error (RE) is 0.4835 using the proposed method, which is reduced by 49.34% and 40.57% compared with FBP and SART separately. Under parallel computation, the computing time of the proposed method reduced 16.56 times compared with the existing bent-ray tracing method. The proposed image reconstruction algorithm is proved to be an effective and improved approach to the liquid-liquid two-phase flow ultrasonic tomography.