In electrical impedance tomography (EIT), ill-posedness in inverse problem is one of the main causes resulting in poor resolution of the reconstructed images. Increasing priori information is a feasible method to improve images quality. In this paper, the polynomial fitting surface of boundary voltages from 3D simulation cylinder model is used to increase priori information. Then, the images are reconstructed using node back projection algorithm ( NBPA). The new method is applied to image reconstruction using two different target-configurations. Then the method is implemented with the 128-channels EIT system designed by the key laboratory in a sail tank on physical model. For the two different target-configurations, the total error of images reconstructed by NBPA is lower than that of conventional back-projection algorithm ( BPA ) by 8. 87% and 6.85% , respectively. In addition, the reconstructed images, resulted from sail tank physical model, display the target clearly. The proposed method is promising in clinical diagnosis and monitoring.%电阻抗成像(EIT)技术中逆问题的病态特性是造成重建图像分辨率较低的主要原因之一,增加先验信息是改善成像效果的可行方法.建立三维圆柱体仿真模型,对边界电压数据进行多项式曲面拟合,增加先验信息,采用节点反投影方法进行图像重建.对两种目标模型进行仿真实验,并利用本实验室设计的128通道EIT系统进行水槽物理模型重建实验.仿真实验结果表明,较之传统的反投影方法,两种目标模型采用节点反投影方法重建的总体误差分别降低了8.87％和6.85％；在物理模型中,重建图像可清晰显示目标物体.所提出的方法有望用于提高临床检测与监护的成像质量.
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