Meeson S, Killingback A L, Blott B H, Mitchell C, Evans D, Milla P J
Department of Physics, University of Southampton, UK.
Physiol Meas. 1996 Nov;17 Suppl 4A:A85-90. doi: 10.1088/0967-3334/17/4a/012.
The signal-to-noise rations for some EIT measurements are very low, and for in vivo EIT measurements these are dependent on the electrode positioning and the distance from the current drive. The effect of removing noisy measurements to produce higher-fidelity images was investigated for the case of gastric emptying data. A consequence of this filtering was the reduction in the size of the sensitivity matrix and its subsequent singular-value decomposition. Several different filters were tested and for each of these spectral expansion regularization filter was optimized using a chi 2 test. Filtering out the measurement made by the spinal electrode, where the spinal bone barrier lies directly in the current path to the stomach, produced improved images by reducing the artefact content in the spinal sector of the conductivity map. For stomach imaging little useful information is produced by the spinal electrode, and the benefits of filtering dominate. However artefact images may be generated. In contrast consistent small improvements were produced by filtering out some of the weakest signals.
一些电阻抗断层成像（EIT）测量的信噪比非常低，对于体内EIT测量，这些信噪比取决于电极定位以及与电流驱动的距离。针对胃排空数据的情况，研究了去除噪声测量以生成更高保真度图像的效果。这种滤波的一个结果是灵敏度矩阵的大小减小及其随后的奇异值分解。测试了几种不同的滤波器，并且针对每种滤波器使用卡方检验对频谱扩展正则化滤波器进行了优化。滤除由脊柱电极进行的测量（脊柱骨屏障直接位于通向胃部的电流路径中），通过减少电导率图脊柱区域中的伪影含量产生了改进的图像。对于胃部成像，脊柱电极产生的有用信息很少，并且滤波的好处占主导。然而，可能会生成伪影图像。相比之下，通过滤除一些最弱的信号产生了一致的小改进。
