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Conference on Electronic Imaging and Multimedia Technology III

作者： Hou, WD Mo, WL Shanghai Univ Dept Commun Engn Shanghai 200072 Peoples R China

ISBN: (纸本)0819447145

image reconstruction in electrical impedance tomography (EIT) is a non-linear inverse problem. The linear model is always used in most of the reconstruction algorithm in dynamic EIT, which causes large errors of image reconstruction. In this paper, we proposed a new image reconstruction method in dynamic Ell In the method the artificial neural network based on the error back propagation algorithm (BP ANN) is used to express the non-linear relation between the impedance change position inside the measured object and the voltage change value measured on the surface of the object. Thus, the location of the impedance change can be decided by the measured voltage change on the surface, and then the impedance change image will be reconstructed with linear approximated method. The reconstructed error will be decreased largely, because the impedance change position can be detected precisely by our proposed method. The experimental results indicate that the precision of the reconstructed image with our method is greatly higher than that with the back projection method.

关键词： image reconstruction algorithm neural network electrical impedance tomography biomedical imaging

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Study on image reconstruction of capacitively coupled electrical impedance tomography (CCEIT)

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MEASUREMENT SCIENCE AND TECHNOLOGY 2019年第9期30卷

作者： Wang, Yuxin Ji, Haifeng Huang, Zhiyao Wang, Baoliang Li, Haiqing Zhejiang Univ State Key Lab Ind Control Tech Coll Control Sci & Engn Hangzhou 310027 Zhejiang Peoples R China

The aim of this work is to study the image reconstruction of capacitively coupled electrical impedance tomography (CCEIT) by using total impedance of a gas-liquid two-phase flow. The results of image reconstruction that utilise the real part, the imaginary part, the amplitude of the impedance, and the image reconstruction results by making use of different parts of the total impedance are investigated and discussed. By combining a linear back projection (LBP) algorithm and a K-means clustering algorithm, a new image reconstruction algorithm for CCEIT is proposed. The LBP is used to obtain the original reconstructed image. The K-means is adopted to automatically obtain the gray level threshold. The final reconstructed image is acquired with an established gray level threshold filter. With the new algorithm (LBP + K-means), the images reconstructed by using different parts of the impedance are obtained. To make full use of total impedance information, an image fusion method based on the weighted combination method is presented. With a developed 12-electrode CCEIT prototype, the image reconstruction experiments are conducted. Experimental results show that all three parts of the impedance can reflect the phase distribution characteristics of the gas-liquid two-phase flow from different aspects. image fusion results indicate that making full use of the different parts of the total impedance of the gas-liquid two-phase flow can effectively improve the quality of the image reconstruction. The experimental results also verify the feasibility and the effectiveness of the proposed new image reconstruction algorithm. Compared with conventional algorithms, the proposed image reconstruction method can obtain comparable/better image reconstruction results with less prior knowledge. The influence of manual intervention on the image reconstruction results can be effectively avoided.

关键词： gas-liquid two-phase flow electrical tomography impedance image reconstruction algorithm K-means image fusion

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A heterogeneous hardware scheme for accelerating the image reconstruction process of electrical tomography

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MEASUREMENT SCIENCE AND TECHNOLOGY 2023年第10期34卷 105902-105902页

作者： Cui, Ziqiang Sun, Can Yang, Pengyu Wang, Huaxiang Tianjin Univ Sch Elect & Informat Engn Tianjin 300072 Peoples R China

Currently, most of the electrical tomography measurement systems are developed on microcontroller units, digital signal processors, or field programmable gate arrays, whereas image reconstruction and display functions are implemented in a separate host computer. Therefore, the complete hardware usually comprises a measurement system and an image reconstruction computer. The current trend is to develop industrial standard electrical tomography systems, which can implement the image reconstruction and measurement functions into an integrated processor/chip. However, most of the above mentioned processors do not provide the necessary computational resources as required by the computationally intensive image reconstruction function. This paper describes a hardware scheme for implementing image reconstruction functions on a heterogeneous hardware platform, wherein the processor system and programmable logics (PLs) are tightly coupled and can achieve better resource utilization and overall system performance. By adopting a high-level synthesis method, the image reconstruction algorithms can be realized jointly by the PLs and processor system. In this hardware scheme, the algorithms are properly optimized to achieve better data throughput and execution efficiency, that is, by utilizing parallel computation in PLs. Details of the hardware scheme and method of accelerating the image reconstruction process are presented in this paper. Implementation results show that the proposed heterogeneous hardware scheme can achieve the image reconstruction rates of 24 and 1700 frames per second while employing the iterative and non-iterative algorithms, respectively.

关键词： electrical tomography high-level synthesis image reconstruction algorithm electrical capacitance tomography hardware accelerator heterogeneous platform

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Memetic reconstruction algorithm for the ECT

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2018年第7期12卷 917-924页

作者： Tong, Guowei Chen, Hongyan Liu, Shi North China Elect Power Univ Sch Control & Comp Engn Beijing 102206 Peoples R China North China Elect Power Univ Sch Energy Power & Mech Engn Beijing 102206 Peoples R China

The practical performance of the electrical capacitance tomography (ECT) instrument largely relies on the accuracy and robustness of the image reconstruction algorithm. Varying from the common imaging methods, in this study, a regularisation-based loss function is proposed to transform the ECT imaging task into an optimisation problem, in which the least trimmed squares method is employed to measure the data fidelity, and the l(p)-norm of the variables is used as the regulariser. An efficient memetic algorithm (MA) that constitutes of the monkey king evolution algorithm and the Fletcher-Reeves conjugate gradient method is developed for solving the proposed loss function. The numerical simulations reveal that the feasibility and robustness of the proposed MA lead to a series of satisfactory results in the ECT field.

关键词： optimisation problem Fletcher–Reeves conjugate gradient method Computer vision and image processing techniques least trimmed squares method capacitance Optimisation techniques electrical capacitance tomography monkey king evolution algorithm Impedance and admittance measurement permittivity measurement numerical simulations Electrical instruments and techniques ECT imaging task optimisation robustness Optical, image and video signal processing image reconstruction electrodes loss function ECT electrical capacitance tomography instrument trimmed squares method least squares approximations image reconstruction algorithm regularisation-based loss function computerised tomography Interpolation and function approximation (numerical analysis) memetic reconstruction algorithm evolutionary computation conjugate gradient methods capacitance measurement Fletcher-Reeves conjugate gradient method data fidelity

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Acoustic tomography system for online monitoring of temperature fields

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IET SCIENCE MEASUREMENT & TECHNOLOGY 2017年第5期11卷 623-630页

作者： Yan, Hua Ma, Zhao Zhou, Ying Gang Shenyang Univ Technol Sch Informat Sci & Engn Shenyang 110870 Liaoning Peoples R China

For online monitoring of complex temperature distributions, an acoustic tomography system based on sound travel-time measurement is developed. For coping with the reverberation phenomenon in actual measurement, an anti-reflection interference measurement method for sound travel-time is proposed based on cross-correlation and peak recognition. In view of the fact the pixel number provided by commonly used reconstruction algorithms, such as least-squares methods, is very limited, radial basis function approximation and regularisation technique are used, which leads to the pixel number of the reconstruction image increasing dramatically. Mixed programming with LabVIEW and MATLAB is used. Queue structure is adopted to make data acquiring program and data processing program parallel. Test results show that the system can run normally as designed. The measurement values of sound travel-time acquired by the proposed method are stable even in strong reflection interference. Test results show that the system can run normally as designed. The measurement values of sound travel-time acquired by the proposed method are stable even in strong reflection interference. The temperature fields reconstructed are coincided with actual fields, and correctly reflect the temperature changes in the measured area with the heater number, heater location and heating time.

关键词： temperature measurement acoustic tomography temperature distribution acoustic variables measurement time measurement reverberation acoustic wave interference acoustic correlation least squares approximations approximation theory image recognition image reconstruction virtual instrumentation mathematics computing data acquisition acoustic tomography system complex temperature distribution monitoring sound traveltime measurement reverberation phenomenon antireflection interference measurement method cross-correlation peak recognition image reconstruction algorithm least-square method radial basis function approximation regularisation technique LabVIEW programming data processing program data acquiring program queue structure MATLAB programming

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Efficient Phase Shift Migration for MIMO 2-D Imaging in Millimeter-Wave Band

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IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS 2021年第2期31卷 215-218页

作者： Yang, Guan Li, Chao Gao, Hang Li, Hongwei Zheng, Shen Fang, Guangyou Chinese Acad Sci Aerosp Informat Res Inst Beijing 100190 Peoples R China Chinese Acad Sci Key Lab Electromagnet Radiat & Sensing Technol Beijing 100190 Peoples R China Univ Chinese Acad Sci Sch Elect Elect & Commun Engn Beijing 100049 Peoples R China

The real-time capability becomes more and more important for the millimeter-wave imaging systems in variety of applications. To achieve this purpose, the imaging scheme with multiple-input-multiple-output (MIMO) is one of the potential ways, while still limited by the high computational complexity of the conventional MIMO image reconstruction algorithm, which is commonly based on the back-projection theorem. In this letter, an efficient phase shift migration (PSM) image reconstruction algorithm was proposed to improve the computation efficiency for MIMO systems 2-D imaging. By decomposing and approximating the PSM operator reasonably, only complex multiplication and Fourier transform (FT) operations are employed which can be easily carried out to reduce computation cost. An MIMO side-looking prototype system was designed for proof experiments in the 100-GHz band. Although the proposed algorithm introduces a negligible phase error, the experimental results show that the error can be ignored and the algorithm can achieve high-precision real-time imaging.

关键词： Imaging MIMO communication image reconstruction Approximation algorithms Real-time systems Radar imaging Microwave imaging image reconstruction algorithm millimeter-wave (MMW) multiple-input– multiple-output (MIMO) radar phase shift migration (PSM)

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Implementation of Step-Frequency Continuous-Wave Scheme in Millimeter-Wave Inline Holography for Interferences Elimination

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IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 2013年 12卷 1176-1179页

作者： Gao, Xiang Li, Chao Sun, Zhaoyang Fang, Guangyou Chinese Acad Sci Key Lab Electromagnet Radiat & Sensing Technol Inst Elect Beijing 100190 Peoples R China

A millimeter-wave (MMW) inline holographic imaging method based on step-frequency continuous-wave (SFCW) scheme is presented in this letter. By analyzing and decomposing the received SFCW power in range domain, it is found that the background and twin-image interferences can be well separated from the image-related term, and therefore can be removed with appropriate range windows. Moreover, a corresponding mathematical algorithm is developed to reconstruct the image from the inline hologram. To validate the effectiveness of the presented approach, a 200-GHz prototype system is designed and fabricated. Experimental results demonstrate the good performance of the imaging system and its potential application in high-resolution target detection.

关键词： image reconstruction algorithm interferences elimination millimeter-wave (MMW) inline holography range domain decomposition step-frequency continuous-wave (SFCW)

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Improvement of signal-to-noise ratio and image stability in magnetic inductance tomography by exploiting transient response analysis

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IET image PROCESSING 2011年第5期5卷 508-512页

作者： Yin, W. Peyton, A. J. Shanghai Maritime Univ Sch Logist Engn Shanghai 200135 Peoples R China Univ Manchester Sch Elect & Elect Engn Manchester Lancs England

This study presents a method to increase the signal-to-noise ratio (SNR) and image stability in magnetic inductance tomography (MIT) data acquisition by exploiting transient response analysis. In front-end circuits for inductance measurements in MIT, a critical step is the phase sensitive demodulation, which includes a low pass filter. When the excitation source is switched from one coil to the next, a transient response occurs as the received voltage level changes. Normally, data acquisition takes place after the transient response finishes and the voltage level becomes nearly constant. In this study, a method is proposed to increase the SNR by exploiting the information embedded in the transient response. Simulation and experimental tests have confirmed the validity of the method;standard deviations of the measured inductance decrease more than 50%. The impact of improvement in SNR in raw inductance measurement on image stability is considered with different image reconstruction algorithms. The error propagation in the image reconstruction process is discussed.

关键词： low pass filter Measurement and error theory inductance measurements measurement errors image reconstruction magnetic inductance tomography image stability detector circuits inductive sensors Optical, image and video signal processing error propagation Impedance and admittance measurement electromagnetic induction image reconstruction algorithm signal-to-noise ratio low-pass filters image processing and restoration transient response analysis tomography inductance measurement phase sensitive demodulation Electrical instruments and techniques Measurement theory Sensing devices and transducers Sensing and detecting devices MIT data acquisition

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Application of ultrasonic tomography to monitoring gas/liquid flow

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CHEMICAL ENGINEERING SCIENCE 1997年第13期52卷 2171-2183页

作者： Xu, LJ Han, YT Xu, LA Yang, JS TIANJIN UNIV DEPT APPL PHYSTIANJIN 300072PEOPLES R CHINA

On the basis that a gas/liquid two-phase flow was considered as a strongly inhomogeneous medium due to the high contrast in acoustic impedance distribution, the authors analysed the inherent dependency of the incomplete tomographic projections on the distribution of bubbles in liquid when using transmission-mode (TM) ultrasound computerized tomography (UCT). A mathematical model describing the acoustic characteristics of this flow was established. A transmission-mode ultrasonic system for tomographic imaging of gas/liquid flow was designed based upon a fast binary back-projection image reconstruction algorithm. Emphasis was made on the evaluation of its performance and its application to flow regime identification. Several flow pattern models were made and the corresponding monitoring results were given. Finally, limitations and possible future implementations of the system are discussed. (C) 1997 Elsevier Science Ltd. All rights reserved.

关键词： gas/liquid two-phase fluid ultrasound transmission-mode (TM) tomography image reconstruction algorithm

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A novel time-difference electrical impedance tomography algorithm using multi-frequency information

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BIOMEDICAL ENGINEERING ONLINE 2019年第1期18卷 1-23页

作者： Cao, Lu Li, Haoting Xu, Canhua Dai, Meng Ji, Zhenyu Shi, Xuetao Dong, Xiuzhen Fu, Feng Yang, Bin Fourth Mil Med Univ Air Force Med Univ Dept Biomed Engn Xian 710032 Shaanxi Peoples R China

BackgroundElectrical impedance tomography (EIT) is a noninvasive, radiation-free, and low-cost imaging modality for monitoring the conductivity distribution inside a patient. Nowadays, time-difference EIT (tdEIT) is used extensively as it has fast imaging speed and can reflect the dynamic changes of diseases, which make it attractive for a number of medical applications. Moreover, modeling errors are compensated to some extent by subtraction of voltage measurements collected before and after the change. However, tissue conductivity varies with frequency and tdEIT does not efficiently exploit multi-frequency information as it only uses measurements associated with a single *** paper proposes a tdEIT algorithm that imposes spectral constraints on the framework of the linear least squares problem. Simulation and phantom experiments are conducted to compare the proposed spectral constraints algorithm (SC) with the damped least squares algorithm (DLS), which is a stable tdEIT algorithm used in clinical practice. The condition number and rank of the matrices needing inverses are analyzed, and image quality is evaluated using four indexes. The possibility of multi-tissue imaging and the influence of spectral errors are also *** performance improvement is achieved by combining multi-frequency and time-difference information. The simulation results show that, in one-step iteration, both algorithms have the same condition number and rank, but SC effectively reduces image noise by 20.25% compared to DLS. In addition, deformation error and position error are reduced by 8.37% and 7.86%, respectively. In two-step iteration, the rank of SC is greatly increased, which suggests that more information is employed in image reconstruction. image noise is further reduced by an average of 32.58%, and deformation error and position error are also reduced by 20.20% and 31.36%, respectively. The phantom results also indicate that SC has stronger nois

关键词： Electrical impedance tomography (EIT) Fraction model image reconstruction algorithm Inverse problem

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