A Magnetic Induction Tomography System for Prospective Industrial Processing Applications

Magnetic induction tomography(MIT) is one of the newest industrial process imaging techniques.Main industrial applications of the MIT imaging are in high conductive flow imaging.However,recently it has been shown that the MIT may be useful for low conductive process imaging.This paper presents a cost effective hardware design for MIT in industrial applications,called Bath-MKI industrial MIT system.The system comprises 8 inductor coils and has the possibility of expansion to 16 coils.The excitation signals and the measured voltages are generated and measured using a LabView based system.Two 16 by 1 multiplexers are used to select between the coils.Measurements,excitation and multiplexing are all controlled by a National Instrument(NI) USB based DAQ:USB-6259 and a signal generator.Using the same electronics,the prototype is tested with two different coil arrays;one is a small scale ferrite core coil and one larger scale air cored coil.Experimental image reconstruction results are shown using both small scale and large scale coil arrays.

Key Algorithm on Medical Inter net of Things Sensor Node Based on Magnetic Induction Tomography

This paper focuses on the key issues of information processing in the new sensing technology-electromagnetic induction tomography and depth theoretical study and experimental simulation have been conducted.In this study,Labview is used to drive the data acquisition card to control the signal generation and acquisition,and Matlab is used to achieve algorithms such as Fast Fourier Transformation (FFT) algorithm,relevant law algorithm and the classical method algorithm.The simulation results show this software system enables successful digital phase identification and the phase difference resolution of 0.10 can be achieved,which is consistent with theoretical analysis.It can also be seen that software system based on Labview and Matlab is a successful method to identify the phase difference in magnetic induction tomography system,which can meet the measurement needs of sensor nodes,laying the basis for the further development of medical IoT study.

Acoustic dipole radiation model for magnetoacoustic tomography with magnetic induction

An acoustic dipole radiation model for magnetoacoustic tomography with magnetic induction （MAT-MI） is pro- posed, based on the analyses of one-dimensional tissue vibration, three-dimensional acoustic dipole radiation and acoustic waveform detection with a planar piston transducer. The collected waveforms provide information about the conductiv- ity boundaries in various vibration intensities and phases due to the acoustic dipole radiation pattern. Combined with the simplified back projection algorithm, the conductivity configuration of the measured layer in terms of shape and size can be reconstructed with obvious border stripes. The numerical simulation is performed for a two-layer cylindrical phantom model and it is also verified by the experimental results of MAT-MI for a tissue-like sample phantom. The proposed model suggests a potential application of conductivity differentiation and provides a universal basis for the further study of conductivity reconstruction for MAT-MI.

Reception pattern influence on magnetoacoustic tomography with magnetic induction

Based on the acoustic radiation theory of a dipole source, the influence of the transducer reception pattern is studied for magnetoacoustic tomography with magnetic induction（MAT-MI）. Numerical studies are conducted to simulate acoustic pressures, waveforms, and reconstructed images with unidirectional, omnidirectional, and strong directional transducers.With the analyses of equivalent and projection sources, the influences of the model dimension and the layer effect are qualitatively analyzed to evaluate the performance of MAT-MI. Three-dimensional simulation studies show that the strong directional transducer with a large radius can reduce the influences of equivalent sources, projection sources, and the layer effect effectively, resulting in enhanced pressure and improved image contrast, which is beneficial for boundary pressure extraction in conductivity reconstruction. The reconstructed conductivity contrast images present the conductivity boundaries as stripes with different contrasts and polarities, representing the values and directions of the conductivity changes of the scanned layer. The favorable results provide solid evidence for transducer selection and suggest potential practical applications of MAT-MI in biomedical imaging.

Simulation research on effect of magnetic nanoparticles on physical process of magneto–acoustic tomography with magnetic induction

Magneto–acoustic tomography with magnetic induction（MAT-MI） is a multiphysics coupled imaging technique that is combined with electrical impedance tomography and ultrasound imaging. In order to study the influence of adding magnetic nanoparticles as a contrast agent for MAT-MI on its physical process, firstly, we analyze and compare the electromagnetic and acoustical properties of MAT-MI theoretically before and after adding magnetic nanoparticles, and then construct a two-dimensional（2 D） planar model. Under the guidance of space-time separation theory, we determine the reasonable simulation conditions and solve the electromagnetic field and sound field physical processes in the two modes by using the finite element method. The magnetic flux density, sound pressure distribution, and related one-dimensional（1 D）, 2 D, and three-dimensional（3 D） images are obtained. Finally, we make a qualitative and quantitative analysis based on the theoretical and simulation results. The research results show that the peak time of the time item separated from the sound source has a corresponding relationship with the peak time of the sound pressure signal. At this moment, MAMPTMI produces larger sound pressure signals, and the sound pressure distribution of the MAMPT-MI is more uniform, which facilitates the detection and completion of sound source reconstruction. The research results may lay the foundation for the MAT-MI of magnetically responsive nanoparticle in subsequent experiments and even clinical applications.

Boundary normal pressure-based electrical conductivity reconstruction for magneto–acoustic tomography with magnetic induction

As a kind of multi-physics imaging approach integrating the advantages of electrical impedance tomography and ul- trasound imaging with the improved spatial resolution and image contrast, magneto-acoustic tomography with magnetic induction （MAT-MI） is demonstrated to have the capability of electrical impedance contrast imaging for biological tissues with conductivity differences. By being detected with a strong directional transducer, abrupt pressure change is proved to be generated by the gradient of the induced Lorentz force along the force direction at conductivity boundary. A simplified boundary normal pressure （BNP）-based conductivity reconstruction algorithm is proposed and the formula for conductivity distribution inside the object with the clear physical meaning of pressure derivative, is derived. Numerical simulations of acoustic pressure and conductivity reconstruction are conducted based on a 2-layer eccentric cylindrical phantom model using Hilbert transform. The reconstructed two-dimensional conductivity images accord well with the model, thus success- fully making up the deficiency of only imaging conductivity boundary in traditional MAT-MI. The proposed method is also demonstrated to have a spatial resolution of one wavelength. This study provides a new method of reconstructing accurate electrical conductivity and suggests the potential applications of MAT-MI in imaging biological tissues with conductivity difference.

A Single Channel Measurement System For Brain MIT

A single channel measurement system for brain MIT has been built. The system is composed of an exciting source unit,a detecting unit,a rotating and controlling unit,and imaging unit. The experiment results of single channel measurements show that the system output versus the conductivity of the objects was an approximate linear relationship when the diameter of an object was about 9cm and its conductivity was in 0.1 S/m,0.7 S/m,2 S/m,6 S/m. The sensitivit yof the phase detector was 53 mV/degree from -10 to +10 degree.

The Application of WT588D Module in MIT System

Compared with traditional magnetic induction tomography (MIT) system, the innovation of this paper is that the function of voice broadcast based on WT588D module is added to the system. The new MIT system avoids frequently looking into the instrument and decreases sartificially reading residual from the hardware debugging to the test process. It makes the process of data acquisition easier and enhances the accuracy and efficiency of detection in the system. It also gives a detailed description to optimize the design of software and hardware. The voice broadcast subsystem has the advantages of simple integral structure, high quality sound, low cost, convenient function expansion, which can be used as a template based on the WT588D modular applied in other related fields.

Magnetoacoustic position imaging for liquid metal in animal interstitial structure

Magnetoacoustic tomography with magnetic induction(MAT-MI),as a new kind of in-vivo imaging method,has potential application value in interstitial fluid research.In this paper,we propose the application of MAT-MI with liquid metal serving as a tracer of the interstitial structure to study its fluid behavior,and use it to implement the positional imaging of the spatial distribution of liquid metal.Owing to the particularity of liquid metal magnetoacoustic pressure(MAP)signals,we propose an envelope analysis method to extract the rising edge of the amplitude envelope of the detected waveform as effective position data.And for the first time,we propose the method of superpositing pixel matrix to achieve the position imaging of liquid metal.Finally,the positional imaging of the liquid metal sample embedded in the gel is achieved to have relatively accurate results.This study provides a method of effectively extracting data and implementing the position imaging for liquid metal in the interstitial structure in the frame of MAT-MI.