说明：  针对ECT图像重建质量有待提高的现状，研究ECT的正问题及逆问题．在多种介质分布下获得投影数据，对LBP法、PLI法和新算法进行了比较研究
(Both positive problem and inverse problem of E凹were investigated to improve reconstruction quality of ECT image．The LBP．PLI and new algorithms were compared extensivel)