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摘要:
电磁层析成像(EMT)中传感器阵列的设置决定了获得的感应电压测量值的数量,对成像的效果有着重要的影响。为了探究传感器设置对成像质量的影响规律,通过改变传感器阵列中线圈的数量及相对位置对传感器阵列进行优化。在COMSOL Multi-physics中建立不同线圈数量的传感器阵列模型,采用不同的成像算法进行成像并比较成像效果,发现适当增加传感器的个数可以提高成像质量,但增加到一定数量则成像效果下降;同时在传感器阵列固定的情况下将传感器阵列按照一定规则进行旋转,发现旋转之后叠加的复合成像效果要优于未旋转的成像效果。该结果对下一步EMT系统设计中传感器阵列的设置具有一定的指导意义。
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关键词:
- 电磁层析成像(EMT) /
- 感应电压 /
- 传感器阵列 /
- 旋转 /
- 成像质量
Abstract:The settings of the sensor array in electromagnetic tomography (EMT) determine the number of induced voltages, which have an important influence on reconstructed image quality. To study the effect of the settings of coils on the quality of reconstructed images, the number and the position of the sensor array are discussed for optimization. In this paper, the models with different numbers of coils and different contributions are established by using COMSOL Multi-physics; the different algorithms are used to image reconstruction and the quality of the constructed images was compared by correlation coefficient. The simulation shows that the image quality improved by increasing the number of sensors, but when increased to a certain number, the image quality will become worse if the number of the coils continue to increase. In order to increase the measurement data instead of increasing the number of the sensor array, the sensor array is rotated. By comparing the image quality before and after rotation, the result shows that the quality of the reconstructed image is obviously improved after the combination. The simulation results can be a guide for the settings of the sensor array in the design of the EMT system in future work.
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Key words:
- electromagnetic tomography (EMT) /
- induced voltage /
- sensor array /
- rotated /
- image quality
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表 1 10线圈相关系数
Table 1. Correlation coefficient with 10 coils
分布 Tikhonov
算法Spilt-Bregman
算法CGLS
算法旋转后
Tikhonov算法复合
数据分布1 0.356 1 0.366 1 0.371 0 0.487 6 0.491 4 分布2 0.355 9 0.386 5 0.372 7 0.405 1 0.434 6 分布3 0.277 8 0.277 8 0.293 4 0.416 2 0.409 5 分布4 0.642 7 0.642 8 0.659 1 0.697 4 0.723 0 表 2 12线圈相关系数
Table 2. Correlation coefficient with 12 coils
分布 Tikhonov
算法Spilt-Bregman
算法CGLS
算法旋转后
Tikhonov算法复合
数据分布1 0.436 8 0.435 0 0.452 8 0.452 1 0.499 2 分布2 0.396 5 0.400 4 0.406 3 0.455 8 0.495 3 分布3 0.365 6 0.364 6 0.374 7 0.423 0 0.460 7 分布4 0.736 8 0.741 4 0.750 8 0.760 9 0.770 0 表 3 16线圈相关系数
Table 3. Correlation coefficient with 16 coils
分布 Tikhonov
算法Spilt-Bregman
算法CGLS
算法旋转后
Tikhonov算法复合
数据分布1 0.426 1 0.426 4 0.416 3 0.440 4 0.469 6 分布2 0.376 5 0.376 7 0.390 5 0.433 4 0.442 6 分布3 0.376 6 0.387 3 0.397 8 0.416 0 0.448 8 分布4 0.644 7 0.644 9 0.640 0 0.673 4 0.711 3 表 4 20线圈相关系数
Table 4. Correlation coefficient with 20 coils
分布 Tikhonov
算法Spilt-Bregman
算法CGLS
算法旋转后
Tikhonov算法复合
数据分布1 0.438 3 0.418 7 0.445 2 0.468 2 0.475 8 分布2 0.433 9 0.432 3 0.427 0 0.440 6 0.484 4 分布3 0.388 5 0.403 6 0.396 7 0.421 4 0.443 0 分布4 0.552 5 0.550 1 0.597 2 0.594 2 0.594 9 -
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