Contactless electrical impedance and ultrasonic tomography: correlation, comparison and complementarity study

Abstract

Electrical tomography (ET) and ultrasonic tomography (UT) techniques are effective and promising super-sensing tools with uses in many industrial process applications. They can create internal mapping images of both electrical and mechanical properties from measurements at the exterior boundaries of domains of interests. There are several different types of ET methods and different modes of UT imaging. Here we focus on contactless ET and contactless UT imaging for liquid masses, enabling fully non-intrusive, integrated mechanical and electrical imaging because direct contact to the process material is often a major limiting factor. ET is sensitive to the distribution of dielectric parameters inside the region of interest, and the highest sensitivity often lies near the outer surface of the boundary. UT has very good responses to the intersections of different phases of materials and has the highest resolution in the central area. Capacitively coupled electrical impedance tomography (CCEIT) is proposed as a contactless ET technique. This work investigates CCEIT based on phase measurements of the electrical impedance between transmitting and receiving electrodes, and UT based on the transmission mode, measuring the time-of-flight between the transmitted signal and the first received signals. A combined sensor which comprises a 16-electrode CCEIT array and a 16-transducer UT array is developed. Experimental results show the performances of the two tomography systems and their dual modality combination. This work highlights various aspects of the correlation, comparison and complementarity between these two contactless imaging techniques. Inclusion material characterization and identification is demonstrated using this novel dual modality.

Total fractional-order variation regularization based image reconstruction method for capacitively coupled electrical resistance tomography

“…where S represents sensitivity matrix, which reflects the change of resistance caused by conductivity variation in the measured domain [28].…”

Multi-frequency fusion ultrasonic tomography for gas–liquid two-phase distribution imaging

“…the fusion image will be combined pixel by pixel (element by element) according to their respective weighting coefficients. The implemented fusion strategy is developed based on [33], considering the feature of UT, expressed as follows:…”

Construction of an Ultrasonic Tomograph for Analysis of Technological Processes in the Field of Reflection and Transmission Waves

“…There is a clear tendency to implement more optimal solutions with an emphasis on active control and optimization [11][12][13][14][15][25][26][27]. There are many numerical methods [1-4, 17, 24, 28, 29], but in order to solve the inverse problem, ultrasound tomography [5][6][7][8][9][10]16] can be used.…”