Measurement and Application of Soft-field Effect in Electrical Tomography

Electrical tomography (ET) is an advanced visualization technique commonly used in medical diagnosis and industrial inspections. Its advantages include no-radiation, non-intrusiveness, rapid response, and low-cost applications. However, its imaging quality is very limited due to its so-called “soft-field” effect. In this paper, we focus on a typical form of ET, namely, electrical resistance tomography (ERT), with a special emphasis on the general evaluation of the “soft-field” effect. Based on the design principle of “hard-field” adopted by most of the existing ERT algorithms, a novel index to measure the soft-field effect is formulated after the detection of representative soft-field characteristics. The index can either select the best one among a group of ERT algorithms or choose the best one among all candidate parameters of any parameter-based ERT algorithm. Experimental results show that the novel index can effectively measure the “soft-field” in the ET imaging process and find the image with the high quality.