• Title/Summary/Keyword: Phase retrieval

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The Performance of Dual Structure CR-CMA Adaptive Equalizer for 16-QAM Signal (16-QAM 신호에 대한 이중 구조 CR-CMA 적응 등화기의 성능)

  • Yoon, Jae-Sun;Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.12 no.5
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    • pp.107-114
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    • 2012
  • In this paper, the concerned existing blind equalizer convergence rate and residual inter-symbol interference using constellation reduced and cost function by separation the real part and an imaginary part, the dual structure CR-CMA(constellation Reduction CMA). The CMA methed compensates amplitude but does no compensate phase, On the other hand, The CMA method compensates both the amplitude and the phase but it has the convergence rate problem, and the MCMA method is a way to solve the phase problem of CMA method compensates both the amplitude and the phase after respectively calculating the real part and imaginary part components. Proposal a new method that the dual structure of CR-CMA, the cost function and error function and respectively calculating the real part and imaginary part components can advantages by improving the CMA and the MCMA algorithms so that the amplitude and phase retrieval and constellation reduce the residual ISI and faster convergence rate and performance is good SER (Symbol Error Ratio) was confirmed by computer simulations.

Identification of ginseng root using quantitative X-ray microtomography

  • Ye, Linlin;Xue, Yanling;Wang, Yudan;Qi, Juncheng;Xiao, Tiqiao
    • Journal of Ginseng Research
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    • v.41 no.3
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    • pp.290-297
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    • 2017
  • Background: The use of X-ray phase-contrast microtomography for the investigation of Chinese medicinal materials is advantageous for its nondestructive, in situ, and three-dimensional quantitative imaging properties. Methods: The X-ray phase-contrast microtomography quantitative imaging method was used to investigate the microstructure of ginseng, and the phase-retrieval method is also employed to process the experimental data. Four different ginseng samples were collected and investigated; these were classified according to their species, production area, and sample growth pattern. Results: The quantitative internal characteristic microstructures of ginseng were extracted successfully. The size and position distributions of the calcium oxalate cluster crystals (COCCs), important secondary metabolites that accumulate in ginseng, are revealed by the three-dimensional quantitative imaging method. The volume and amount of the COCCs in different species of the ginseng are obtained by a quantitative analysis of the three-dimensional microstructures, which shows obvious difference among the four species of ginseng. Conclusion: This study is the first to provide evidence of the distribution characteristics of COCCs to identify four types of ginseng, with regard to species authentication and age identification, by X-ray phase-contrast microtomography quantitative imaging. This method is also expected to reveal important relationships between COCCs and the occurrence of the effective medicinal components of ginseng.

A Study of Three-Dimensional Measurement By Transmission Deflectometry and Hilbert Transform (Hilbert 변환과 투과형 편향법을 이용한 3차원 측정연구)

  • Na, Silin;Yu, Younghun
    • Korean Journal of Optics and Photonics
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    • v.27 no.2
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    • pp.61-66
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    • 2016
  • We used transmission deflectometry to measure the three-dimensional shapes of optical components, and we used the Hilbert transform to retrieve the phases from measured deformed fringe images. Deflectometry is useful for measuring large-scale samples, and specular samples. We have retrieved the phases from deformed fringe images and Hilbert-transformed images, and have used the least-squares method to find the height information. We have verified that phase retrieval using Hilbert transform is useful by computer simulation and experiment.

Two-Dimensional Phase Retrieval Using Window Functions (윈도우 함수를 이용한 2차원 신호의 위상복원)

  • Kim, Woo-Shik
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.10
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    • pp.126-134
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    • 1998
  • In this paper, we consider the problem of reconstructing a two-dimensional signal from its Fourier intensity and the Fourier intensities of two windowed signals: one by a window w(m,n) and the other by its complementary window [1-w(m,n)]. We develop several conditions under which a signal can be uniquely specified to within several trivial ambiguities such as sign, translation,and time-reversal from the given conditions. We present two possible reconstruction algorithms derived from the Gerchberg-Saxton algorithm.

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The Simulation Design and Analysis Method of Integrated Logistics System using an Aspect Oriented Approach (Aspect-Oriented Approach를 이용한 통합 물류 시스템의 시뮬레이션 설계 및 분석 방법)

  • Kim, Tae-Ho;Um, In-Sup;Lee, Hong-Chul
    • IE interfaces
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    • v.20 no.4
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    • pp.438-447
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    • 2007
  • This paper presents an aspect-oriented approach to simulation design and analysis in system design phase for integrated logistics system simulation. The integrated logistics system composed of AS/RS (Automated Storages and Retrieval System), AGVs (Automated Guided Vehicle System), STVs (Sorting Transfer Vehicle System) and Conveyor System is designed by using the aspect-oriented approach and UML (Unified Modeling Language). The multi-factorial design of experiments and regression analysis are used for design parameters of the system and Evolution Strategies is used to verify each parameter. Aspect-oriented approach for the integrated logistics system simulation shows the advantages of code reusability, extendible, modulation, easy improvement and a better design technique.

Reflective Fourier Ptychographic Microscopy Using Segmented Mirrors and a Mask

  • Ahn, Hee Kyung;Chon, Byong Hyuk
    • Current Optics and Photonics
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    • v.5 no.1
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    • pp.40-44
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    • 2021
  • In this paper, LED arrays with segmented mirrors and a mask are presented as a new dark-field illuminator for reflective Fourier ptychographic microscopy (FPM). The illuminator can overcome the limitations of the size and the position of samples that the dark-field illuminator using a parabolic mirror has had. The new concept was demonstrated by measuring a USAF 1951 target, and it resolved a pattern in group 10 element 6 (274 nm) in the USAF target. The new design of the dark-field illuminator can enhance competitiveness of the reflective FPM as a versatile measurement method in industry.

JCBP : A Case-Based Planning System (JCBP : 사례 기반 계획 시스템)

  • Kim, In-Cheol;Kim, Man-Soo
    • Journal of Intelligence and Information Systems
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    • v.14 no.4
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    • pp.1-18
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    • 2008
  • By using previous similar case plans, the case-based planning (CBP) systems can generate efficiently plans for new problems. However, most existing CBP systems show limited functionalities for case retrieval and case generalization. Moreover, they do not allow their users to participate in the process of plan generation. To support efficient memory use and case retrieval, the proposed case-based planning system, JCBP, groups the set of cases sharing the same goal in each domain into individual case bases and maintains indexes to these individual case bases. The system applies the heuristic knowledge automatically extracted from the problem model to the case adaptation phase. It provides a sort of case generalization through goal regression. Also JCBP can operate in an interactive mode to support a mixed-initiative planning. Since it considers and utilizes user's preference and knowledge for solving the given planning problems, it can generate solution plans satisfying more user's needs and reduce the complexity of plan generation.

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VERTICAL OZONE DENSITY PROFILING BY UV RADIOMETER ONBOARD KSR-III

  • Hwang Seung-Hyun;Kim Jhoon;Lee Soo-Jin;Kim Kwang-Soo;Ji Ki-Man;Shin Myung-Ho;Chung Eui-Seung
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.372-375
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    • 2004
  • The UV radiometer payload was launched successfully from the west coastal area of Korea Peninsula aboard KSR-III on 28, Nov 2002. KSR-III was the Korean third generation sounding rocket and was developed as intermediate step to larger space launch vehicle with liquid propulsion engine system. UV radiometer onboard KSR-III consists of UV and visible band optical phototubes to measure the direct solar attenuation during rocket ascending phase. For UV detection, 4 channel of sensors were installed in electronics payload section and each channel has 255, 290, 310nm center wavelengths, respectively. 450nm channel was used as reference for correction of the rocket attitude during the flight. Transmission characteristics of all channels were calibrated precisely prior to the flight test at the Optical Lab. in KARI (Korea Aerospace Research Institute). During a total of 231s flight time, the onboard data telemetered to the ground station in real time. The ozone column density was calculated by this telemetry raw data. From the calculated column density, the vertical ozone profile over Korea Peninsula was obtained with sensor calibration data. Our results had reasonable agreements compared with various observations such as ground Umkhr measurement at Yonsei site, ozonesonde at Pohang site, and satellite measurements of HALOE and POAM. The sensitivity analysis of retrieval algorithm for parameters was performed and it was provided that significant error sources of the retrieval algorithm.

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Cancellation of MRI Motion Artifact in Image Plane (촬상단면내의 MRI 체동 아티팩트의 제거)

  • Kim, Eung-Kyeu
    • Journal of KIISE:Software and Applications
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    • v.27 no.4
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    • pp.432-440
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    • 2000
  • In this study, a new algorithm for canceling MRI artifact due to translational motion in image plane is described. Unlike the conventional iterative phase retrieval algorithm, in which there is no guarantee for the convergence, a direct method for estimating the motion is presented. In previous approaches, the motions in the x(read out) direction and the y(phase encoding) direction are estimated simultaneously. However, the features of x and y directional motions are different from each other. By analyzing their features, each x and y directional motion is canceled by different algorithms in two steps. First, it is noticed that the x directional motion corresponds to a shift of the x directional spectrum of the MRI signal, and the non-zero area of the spectrum just corresponds to the projected area of the density function on the x-axis. So the motion is estimated by tracing the edges between non-zero area and zero area of the spectrum, and the x directional motion is canceled by shifting the spectrum in inverse direction. Next, the y directional motion is canceled by using a new constraint condition, with which the motion component and the true image component can be separated. This algorithm is shown to be effective by using a phantom image with simulated motion.

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Implementation of an Efficient Microbial Medical Image Retrieval System Applying Knowledge Databases (지식 데이타베이스를 적용한 효율적인 세균 의료영상 검색 시스템의 구현)

  • Shin Yong Won;Koo Bong Oh
    • Journal of the Korea Society of Computer and Information
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    • v.10 no.1 s.33
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    • pp.93-100
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    • 2005
  • This study is to desist and implement an efficient microbial medical image retrieval system based on knowledge and content of them which can make use of more accurate decision on colony as doll as efficient education for new techicians. For this. re first address overall inference to set up flexible search path using rule-base in order U redure time required original microbial identification by searching the fastest path of microbial identification phase based on heuristics knowledge. Next, we propose a color ffature gfraction mtU, which is able to extract color feature vectors of visual contents from a inn microbial image based on especially bacteria image using HSV color model. In addition, for better retrieval performance based on large microbial databases, we present an integrated indexing technique that combines with B+-tree for indexing simple attributes, inverted file structure for text medical keywords list, and scan-based filtering method for high dimensional color feature vectors. Finally. the implemented system shows the possibility to manage and retrieve the complex microbial images using knowledge and visual contents itself effectively. We expect to decrease rapidly Loaming time for elementary technicians by tell organizing knowledge of clinical fields through proposed system.

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