Continuous-wave ultrasonic tomography for oil/water two-phase flow imaging using regularized weighted least square framework

Abstract

Two-phase flow is a regime that commonly existed in many applications of process industry, on which the technique of ultrasonic tomography (UT) could provide reliable measurement with benefits of non-invasion, non-radiation and low-cost. In order to provide considerable visualization of low acoustic impedance contrast configurations in two-phase flow, a regular weighted simultaneous algebraic reconstruction technique (RW-SART) using continuous-wave excitation is proposed and presented in detail. With measurement strategy and formulized reconstruction model introduced, the measurement system is introduced with modification on continuous-wave excitation module and fan-beam angle transducers. A regularized weighted least square (RWLS) framework combining total variation (TV) regularization and SART reconstruction is derived and presented in detail to address the problem that under-determined and ill-conditioned situation couldn’t be resolved simultaneously. Both numerical simulation and experimental investigation are conducted to validate the feasibility of continuous-wave excitation and the improvement of proposed reconstruction strategy, from which the distribution of oil-water two-phase flow is effectively reconstructed. The implementation of measurement system provides an option of continuous high-voltage excitation and measurement in UT. By utilizing both the geometric information and penalty constraint, the proposed reconstruction approach provides a framework that introduces regularization information to the algebraic iteration reconstruction. Consequently, it has better reconstruction result than TV, Landweber, L1, filtered back projection (FBP) and SART method.

Handwriting With Sound-Speed Imaging Using Ultrasound Computed Tomography

“…The paper shows a new type of HCI using ultrasound computed tomography (USCT) with an experimental demonstration in producing handwriting of letters and words. The USCT has been lately developed for breast cancer imaging with clinical success [9], [10], and in industrial process monitoring [11], [12], [13], [14]. The common scientific topic that USCT can take advantage of in all these applications is high-quality imaging over time combining qualitative and temporal features with significant outcomes.…”

Multi-frequency fusion ultrasonic tomography for gas–liquid two-phase distribution imaging

“…Xu and Xu [2] validated its feasibility, where the major difference compared with conventional ultrasound imaging is that industrial UT faces a closed testing domain with a restrained number of transducers. The UT research is continuously improving from offline approaches [3] to online systems [4], real-time reconstruction algorithms [5] and novel sensing strategies, such as linear parallel reflection [6], multi-wave measurement [7], fan-beam transducers [8], continuous-wave attenuation [9] and simultaneous excitation [10,11]. From the perspective of measurement strategy, the receiving signal can be categorized into transmission mode (T-mode) and reflection mode (R-mode) with the transceivers distributed on the opposite or thesame side of the testing domain.…”