• Title, Summary, Keyword: Microwave Imaging

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Development of Effective Analytical Signal Models for Functional Microwave Imaging

  • Baang, Sung-Keun;Kim, Jong-Dae;Lee, Yong-Up;Park, Chan-Young
    • Journal of Biomedical Engineering Research
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    • v.28 no.4
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    • pp.471-476
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    • 2007
  • Various active microwave imaging techniques have been developed for cancer detection for past several decades. Both the microwave tomography and the UWB radar techniques, constituting functional microwave imaging systems, use the electrical property contrast between normal tissues and malignancies to detect the latter in an early development stage. Even though promising simulation results have been reported, the understanding of the functional microwave imaging diagnostics has been relied heavily on the complicated numerical results. We present a computationally efficient and physically instructive analytical electromagnetic wave channel models developed for functional microwave imaging system in order to detect especially the breast tumors as early as possible. The channel model covers the propagation factors that have been examined in the previous 2-D models, such as the radial spreading, path loss, partial reflection and transmission of the backscattered electromagnetic waves from the tumor cell. The effects of the system noise and the noise from the inhomogeneity of the tissue to the reconstruction algorithm are modeled as well. The characteristics of the reconstructed images of the tumor using the proposed model are compared with those from the confocal microwave imaging.

Characteristics of the Contact Angle Using the Microwave Plasma Treatment on Scintillator Panel Substrates (마이크로웨이브 플라즈마 처리를 통한 섬광체 패널 기판의 접촉가 특성변화)

  • Kim, Byoungwook;Kim, Youngju;Ryu, Cheolwoo;Choi, Byoungjung;Kwon, Youngman;Lee, Youngchoon;Kim, Myungsoo;Cho, Gyuseong
    • Journal of Radiation Industry
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    • v.8 no.1
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    • pp.43-47
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    • 2014
  • By measuring decrease change of the contact angle after microwave plasma treatment on the glass and Al as a scintillator panel sample substrate, the adhesive performance of scintillator panel can be expected to improve. Also resolution and sensitivity of scintillator panel after microwave plasma treatment can be expected to maintain highly.

SPATIO-SPECTRAL MAXIMUM ENTROPY METHOD: II. SOLAR MICROWAVE IMAGING SPECTROSCOPY

  • Bong, Su-Chan;Lee, Jeong-Woo;Gary Dale E.;Yun Hong-Sik;Chae Jong-Chul
    • Journal of The Korean Astronomical Society
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    • v.38 no.4
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    • pp.445-462
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    • 2005
  • In a companion paper, we have presented so-called Spatio-Spectral Maximum Entropy Method (SSMEM) particularly designed for Fourier-Transform imaging over a wide spectral range. The SSMEM allows simultaneous acquisition of both spectral and spatial information and we consider it most suitable for imaging spectroscopy of solar microwave emission. In this paper, we run the SSMEM for a realistic model of solar microwave radiation and a model array resembling the Owens Valley Solar Array in order to identify and resolve possible issues in the application of the SSMEM to solar microwave imaging spectroscopy. We mainly concern ourselves with issues as to how the frequency dependent noise in the data and frequency-dependent variations of source size and background flux will affect the result of imaging spectroscopy under the SSMEM. We also test the capability of the SSMEM against other conventional techniques, CLEAN and MEM.

3D Microwave Breast Imaging Based on Multistatic Radar Concept System

  • Simonov, Nikolai;Jeon, Soon-Ik;Son, Seong-Ho;Lee, Jong-Moon;Kim, Hyuk-Je
    • Journal of electromagnetic engineering and science
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    • v.12 no.1
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    • pp.107-114
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    • 2012
  • Microwave imaging (MI) is one of the most promising and attractive new techniques for earlier breast cancer detection. Microwave tomography (MT) realizes configuration of a multistatic multiple-input multiple-output system and reconstructs dielectric properties of the breast by solving a nonlinear inversion scattering problem. In this paper, we describe ETRI 3D MT system with 3D MI reconstruction program and demonstrate its robustness through some examples of the image reconstruction.

Robust Transmission Waveform Design for Distributed Multiple-Radar Systems Based on Low Probability of Intercept

  • Shi, Chenguang;Wang, Fei;Sellathurai, Mathini;Zhou, Jianjiang;Zhang, Huan
    • ETRI Journal
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    • v.38 no.1
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    • pp.70-80
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    • 2016
  • This paper addresses the problem of robust waveform design for distributed multiple-radar systems (DMRSs) based on low probability of intercept (LPI), where signal-to-interference-plus-noise ratio (SINR) and mutual information (MI) are utilized as the metrics for target detection and information extraction, respectively. Recognizing that a precise characterization of a target spectrum is impossible to capture in practice, we consider that a target spectrum lies in an uncertainty class bounded by known upper and lower bounds. Based on this model, robust waveform design approaches for the DMRS are developed based on LPI-SINR and LPI-MI criteria, where the total transmitting energy is minimized for a given system performance. Numerical results show the effectiveness of the proposed approaches.

Preclinical Prototype Development of a Microwave Tomography System for Breast Cancer Detection

  • Son, Seong-Ho;Simonov, Nikolai;Kim, Hyuk-Je;Lee, Jong-Moon;Jeon, Soon-Ik
    • ETRI Journal
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    • v.32 no.6
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    • pp.901-910
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    • 2010
  • As a supplement to X-ray mammography, microwave imaging is a new and promising technique for breast cancer detection. Through solving the nonlinear inverse scattering problem, microwave tomography (MT) creates images from measured signals using antennas. In this paper, we describe a developed MT system and an iterative Gauss-Newton algorithm. At each iteration, this algorithm determines the updated values by solving the set of normal equations using Tikhonov regularization. Some examples of successful image reconstruction are presented.

Analysis of Solar Microwave Burst Spectrum, I. Nonuniform Magnetic Field

  • Lee, Jeongwoo
    • Journal of Astronomy and Space Sciences
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    • v.35 no.4
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    • pp.211-218
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    • 2018
  • Solar microwave bursts carry information about the magnetic field in the emitting region as well as about electrons accelerated during solar flares. While this sensitivity to the coronal magnetic field must be a unique advantage of solar microwave burst observations, it also adds a complexity to spectral analysis targeted to electron diagnostics. This paper introduces a new spectral analysis procedure in which the cross-section and thickness of a microwave source are expressed as power-law functions of the magnetic field so that the degree of magnetic inhomogeneity can systematically be derived. We applied this spectral analysis tool to two contrasting events observed by the Owens Valley Solar Array: the SOL2003-04-04T20:55 flare with a steep microwave spectrum and the SOL2003-10-19T16:50 flare with a broader spectrum. Our analysis shows that the strong flare with the broader microwave spectrum occurred in a region of highly inhomogeneous magnetic field and vice versa. We further demonstrate that such source properties are consistent with the magnetic field observations from the Michelson Doppler Imager instrument onboard the Solar and Heliospheric Observatory (SOHO) spacecraft and the extreme ultraviolet imaging observations from the SOHO extreme ultraviolet imaging telescope. This spectral inversion tool is particularly useful for analyzing microwave flux spectra of strong flares from magnetically complex systems.

Study on Imaging with Scanning Airborne W-band Millimeter Wave Radiometer

  • Kong, De-Cai;Kim, Yong-Hoon;Li, Jing;Zhang, Sheng-Wei;Sun, Mao-Hua;Liu, He-Guang;Jiang, Jing-Shan
    • Proceedings of the KSRS Conference
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    • pp.593-597
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    • 2002
  • The paper introduces a research on the W-band Millimeter Wave Radiometer(RADW92) through an airborne experiment. Microwave remote sensing images of part of the Yellow River and the WeiHe River are of fared. Analysis of factors influencing the image qualities as well as the resolutions to them are also included. The RADW92 is the first generation of Millimeter Wave Radiometer in China, which works with operating frequency 92 GHz, the bandwidth 2 GHz, the integration time 60ms, the system sensitivity 0.6k and the linearity better than 0.999. Cassegrain Antenna is designed for imaging by conically scanning. The result of the experiment suggested that RADW92 had been adequate for space use.

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3D Microwave Imaging Technology for Damage Detection of Concrete Structures (콘크리트 구조물의 결함발견을 위한 3차원 초단파 영상처리기법의 개발)

  • Kim, Yoo-Jin;Kim, Yong-Gon
    • Journal of the Korean Society of Safety
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    • v.18 no.4
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    • pp.98-104
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    • 2003
  • Various nondestructive evaluation (NDE) techniques have been studied to locate steel rebars of dowel, and to detect invisible damage such as voids and cracks inside concrete and debonding between rebars and concrete caused by corrosions and earthquakes. In this study, the aurhors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars of dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna array was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. This paper presents the analytical expressions of numerical focusing procedures for 3D image reconstruction and numerical simulation to study the resolution of the system and the effectiveness of multi-frequency technique. Also, the design of 4?4 antenna array with switching devices is introduced as a preliminary study for the final design of whole array.