Development of Ultrasonic CT System Using Inverse Transmission-Line Matrix Modeling

利用逆传输线矩阵建模开发超声 CT 系统

• 批准号: 09650269
• 负责人: TSUCHIYA Takao
• 金额: $ 1.47万
• 依托单位: Okayama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650269/
• 关键词: TLM Method; Ultrasonic CT; Inverse Propagation; Inverse Problem; Sound Wave Propagation; 再構成画像; 離散ホイヘンスモデル

The inverse transmission-line matrix modeling is applied to a ultrasonic computer tomography (CT). Two-dimensional acoustic field is considered for the numerical simulations. Some numerical demonstrations are made for several objects. For the case that the density of the object is only different from the ambient medium, the shape of the object is well reconstructed. It is found that the inverse transmission-line matrix modeling is capable for the computer tomography. For another case that the sound speed of the object is only different from the ambient medium, the reconstructed shape of object is deformed. The object shape can not be reconstructed for the case that the separation of measurement points is lager than the wavelength of projected sound wave. Through the experiments under the water, the measured waveforms at the several position in front of the ultrasonic transducer qualitatively agree with the calculated TLM solutions for the forward propagation process. The measured waveforms are then inputted into the computer program developed for the inverse propagation. It is confirmed that the sound waves propagate reversely to the primary sound source.

将逆传输线矩阵建模应用于超声计算机层析成像（CT）。二维声场被认为是数值模拟。并对几个目标进行了数值模拟。对于物体的密度仅与周围介质不同的情况，物体的形状被很好地重建。结果表明，逆传输线矩阵模型可以用于计算机层析成像。对于另一种情况，即物体的声速与周围介质的声速不同，物体的重建形状发生变形。当测点间距大于投影声波的波长时，无法重建物体的形状。通过水下实验，在超声换能器前几个位置的测量波形定性地与前向传播过程的计算TLM解一致。然后将测量的波形输入为逆传播开发的计算机程序。确认声波反向传播到主声源。