Two-phase flow widely exists in the process industry, where ultrasonic tomography provides reliable visualization with benefits of noninvasion, nonradiation, and low-cost. To provide real-time reconstruction of low acoustic impedance contrast medium distribution existed in two-phase flow, a novel approach using continuous-wave excitation is proposed. With the basic measurement model introduced, a subspace filtered reconstruction algorithm is introduced with improvements on both accuracy and speed. Through nonuniform shape constrained range filter, the relative image error (RE) is reduced by 32.94% and 33.03% compared to simultaneous algebraic reconstruction technique (SART) and filter back projection (FBP) methods. Through derivation of offline iteration/online reconstruction (OIOR) method and truncated singular value decomposition (TSVD), the computing speed increases to 122 frame/s, which fits the requirement of online monitoring. A prototype of the measurement system is introduced with improved design of bipolar high-voltage excitation module and fan-beam angle piezoelectric transducers. Qualitative and quantitative results show that the proposed method has better image accuracy compared to conventional methods.

中文翻译：

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使用连续波激励实时重建低对比度超声断层扫描

两相流广泛存在于过程工业中，其中超声波断层扫描提供可靠的可视化，具有无侵入、无辐射和低成本的优点。为了实时重建两相流中存在的低声阻抗造影剂分布，提出了一种使用连续波激励的新方法。引入基本测量模型后，引入了子空间滤波重建算法，在精度和速度上都有所提高。通过非均匀形状约束范围滤波器，与同步代数重建技术 (SART) 和滤波器反投影 (FBP) 方法相比，相对图像误差 (RE) 降低了 32.94% 和 33.03%。通过离线迭代/在线重构（OIOR）方法和截断奇异值分解（TSVD）的推导，计算速度提高到122帧/秒，满足在线监控的需求。介绍了改进设计的双极高压激励模块和扇形束角压电换能器的测量系统原型。定性和定量结果表明，与传统方法相比，所提出的方法具有更好的图像精度。