• Title/Summary/Keyword: 2차원 이산 푸리에 변환

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A Study on the Estimation of Ocean Surface Wave Information from Marine Radar Signals (선박 레이더 영상신호를 이용한 파랑정보 검출에 관한 연구)

  • Song, Chae-Uk;Kim, Chang-Je;Moon, Seong-Bae
    • Journal of Navigation and Port Research
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    • v.27 no.5
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    • pp.499-504
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    • 2003
  • This paper describes the system for evaluating the sea wave informations such as wave direction and wave length in real time, by using image data obtained from the marine X-band radar. We proposed here a method for automatic selection of the partial image data without the user's individual selection at the radar. We also discussed that the wave direction could be obtained by a 2-dimensional discrete Fourier transform algorithm. We carried some evaluation works on the algorithm through computer simulation. The obtained thirteen radar image data under several sea surface conditions were analyzed by the method described and the result was presented.

Image Analysis for Discrimination of Neoplastic Cellis in Spatial Frequency Domain (종양세포식별을 위한 공간주파수영역에서의 화상해석)

  • 나철훈;김창원;김현재
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.3
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    • pp.385-396
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    • 1993
  • In this paper, a improved method of digital image analysis required in basic medical science for diagnosis of cells was proposed. The object image was the thyroid gland cell image, and the purpose was automatic discrimination of three classes cells(normal cell, follicular neoplastic cells, and papillary neoplastic cells) by difference of chromatin patterns. To segment the cell nucleus from background, the region segmentation algorithm by edge tracing was proposed. And feature parameter was obtained from discrete Fourier transformation of image. After construct a feature sample group of each cells, experiment of discrimination was executed with any verification cells. As a consequency of using features proposed in this paper, get a better recognition rate(70-90%) than previously reported papers, and this method give shape to get objectivity and fixed quantity in diagnosis of cells, The methods described in this paper be used immediately for discrimination of neoplastic cells.

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A DFT Deblurring Algorithm of Blind Blur Image (무정보 blur 이미지 복구를 위한 DFT 변환)

  • Moon, Kyung-Il;Kim, Chul
    • Journal of The Korean Association of Information Education
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    • v.15 no.3
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    • pp.517-524
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    • 2011
  • This paper presents a fast blind deconvolution method that produces a deblurring result from a single image in only a few seconds. The high speed of our method is enabled by considering the Discrete Fourier Transform (DFT), and its relation to filtering and convolution, and fast computation of Moore-Penrose inverse matrix. How can we predict the behavior of an arbitrary filter, or even more to the point design a filter to achieve certain specifications. The idea is to study the frequency response of the filter. This concept leads to an useful convolution formula. A Matlab implementation of our method usually takes less than one minute to deblur an image of moderate size, while the deblurring quality is comparable.

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