基于轮廓形状的肺部电阻抗成像三维插值方法

肺部三维信息利于医生做出更快更准确的诊断,但肺部三维重建的图像都是源自二维断层图像的叠加.二维图像的数量制约三维成像的效果,增加电极层数可获取更多层的二维图像,但同时也会增加计算量,减缓成像速度.虽然采取层间插值的方法可以解决这个问题,但是由于人体几何结构的特异性,肺部电阻抗图像(electrical impedance tomography,EIT)边界不规则,传统的规则图像插值方法不适合直接应用于肺部EIT三维插值.为此,提出适用于肺部电阻抗的插值算法,先获得插值图像轮廓,再用对应点插值像素值.通过仿真和实验验证新插值算法成像的相对误差比线性插值、样条插值成像的相对误差分别降低5.69％、3.3％.基于轮廓形状的肺部电阻抗三维插值方法,能在测量数据量有限的条件下,进一步提高三维电阻抗成像质量,更好地反映肺部的真实形态.

Three dimensional interpolation method of pulmonary electrical impedance tomography based on contour shape

3D lung information can help doctors making faster and more accurate diagnosis. However, 3D lung reconstruction is derived from stacking of two-dimensional tomographic images. The quantity of two-dimensional images restricts the quality of 3D reconstruction. Increasing the number of electrode layers could achieve more two-dimensional images. However, the calculation complexity is increased and imaging speed is down. The inter-layer interpolation can solve this problem, however, the specificity and irregularity of human body geometry make electrical impedance tomography (EIT) lung images irregular. As a result, the traditional interpolation algorithm suitable only for regular images which cannot be directly applied to EIT images. Thus, a three-dimensional interlayer interpolation algorithm suitable for pulmonary electrical impedance is proposed. Firstly, the contour of the interpolated image is obtained, and then the pixel value is interpolated with the corresponding point. Simulation and experiment verify that the relative error of the new interpolation algorithm is 5. 69%, 3. 3% lower than that of linear interpolation and spline interpolation respectively. The three-dimensional interpolation method based on contour shape can further improve the quality of three-dimensional electrical impedance imaging and better reflect the real shape of the lung under the condition of limited measurement data.