• 제목/요약/키워드: Transform

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A Study on Transform Coding of Image Signal using Microcomputer (마이크로컴퓨터를 이용한 영상신호의 변환부호화에 관한 연구)

  • 황재정;김종교;이문호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • 제11권3호
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    • pp.197-203
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    • 1986
  • The images which are scanned by CCTV are converted to digital signal and 6502 Microcomputer processes data by Transform coding. Thus data is reduced to $64{ imes}64$pixels and input by outer memory using same address with inner one for the fast process. Hadmard Transform, Weighted Hadamard Transform which is weighted in the center of matrix and Haar Transform are programmed by assembly language and every Transform is dome within one second.

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Two dimensional FFT by Polynomial Transform (Polynomial 변환을 이용한 고속 2 차원 FFT)

  • 최환석;김원하;한승수
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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    • pp.473-476
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    • 2003
  • We suggest 2 dimensional Fast Fourier Transform using Polynomial Transform and integer Fast Fourier Transform. Unlike conventional 2D-FFT using the direct quantization of twiddle factor, the suggested 2D-FFT adopts implemented by the lifting so that the suggested 2D-FFT is power adaptable and reversible. Since the suggested FFT performg integer-to-integer mapping, the transform can be implemented by only bit shifts and auditions without multiplications. In addition. polynomial transform severely reduces the multiplications of 2D-FFT. While preserving the reversibility, complexity of this algorithm is shown to be much lower than that of any other algorithms in terms of the numbers of additions and shifts.

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Optical hough transform by use of rotationally multiplexed holograms (회전다중 홀로그램을 이용한 광학적 Hough 변환)

  • 신동학;장주석
    • Journal of the Korean Institute of Telematics and Electronics D
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    • 제34D권11호
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    • pp.64-69
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    • 1997
  • We have shown that the Hough transform filter can be easily obtained by repeatedly recording one line segment pattern holographically by use of rotational multiplexing. With this filter, one can get resutls of the hough transform in the time of light propagation. To demonstrate our method experimentally, the hough transform filter for 18 different rottion angles was recorded, and experimental transform results were compared with simulated ones for a few input patterns. By introducing a compensation process for the non-uniformity of both the input plane wav eand the diffraction efficiency of each hologram. It is possible to get more precise transform results.

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CAD-Based 3-D Object Recognition Using the Robust Stereo Vision and Hough Transform (강건 스테레오 비전과 허프 변환을 이용한 캐드 기반 삼차원 물체인식)

  • 송인호;정성종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 한국정밀공학회 1997년도 추계학술대회 논문집
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    • pp.500-503
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    • 1997
  • In this paper, a method for recognizing 3-D objects using the 3-D Hough transform and the robust stereo vision is studied. A 3-D object is recognized through two steps; modeling step and matching step. In modeling step, features of the object are extracted by analyzing the IGES file. In matching step, the values of the sensed image are compared with those of the IGES file which is assumed to location and orientation in the 3-D Hough transform domain. Since we use the 3-D Hough transform domain of the input image directly, the sensitivity to the noise and the high computational complexity could be significantly allcv~ated. Also, the cost efficiency is improved using the robust stereo vision for obtaining depth map image which is needed for 3-D Hough transform. In order lo verify the proposed method, real telephone model is recognized. Thc results of the location and orientation of the model are presented.

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A Study on the Time-Frequency Analysis of Transient Signal using Wavelet Transformation (Wavelet 변환을 이용한 과도신호의 시간-주파수 해석에 관한 연구)

  • 이기영;박두환;정종원;김기현;이준탁
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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    • pp.219-223
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    • 2002
  • Voltage and current signals during impulse tests on transformer are treated as non-stationary signals. A new method incorporating signal-processing method such as Wavelets and courier transform is proposed for failure identification. It is now possible to distinguish failure during impulse tests. The method is experimentally validated on a transformer winding. The wavelet transforms enables the detection of the time of occurrence of switching or failure events. After establishing the time of occurrence, the original waveform is split into two or more sections. The wavelet transform has ability to analysis the failure signal on time domain as well as frequency domain. Therefore, the wavelet transform is superior than courier transform to analysis the failure signal. In this paper, the fact was proved by real data which was achieved.

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Measurement of Mode Shape By Using A Scanning Laser Doppler Vibrometer (스캐닝 레이저 도플러 진동계를 이용한 모드 해석)

  • Gang, Min-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • 제24권10호
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    • pp.2560-2567
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    • 2000
  • When spatially dense velocity distribution is measured by a scanning laser Doppler vibrometer, the Fourier transform method provides the real and imaginary parts of the mode shapes in the form of a polynomial. However the Fourier transform method is often impractical because the independent decomposition property of cosine and sine components into real and imaginary parts, respectively, does not hold due to the leakage problem which commonly occurs in the Fourier transform of harmonic signals. To deal with this problem, a Hilbert transform method is newly proposed in this article. The proposed method is free from the leakage problem and relatively robust to the scanning error. A simulation example is provided to verify the effectiveness of this method.

Note on the generalized Fourier-Feynman transform on function space (함수공간에서의 일반화된 푸리에-파인만 변환에 관한 고찰)

  • Chang, Seung-Jun
    • Journal for History of Mathematics
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    • 제20권3호
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    • pp.73-90
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    • 2007
  • In this paper, we define a generalized Feynman integral and a generalized Fourier-Feynman transform on function space induced by generalized Brownian motion process. We then give existence theorems and several properties for these concepts. Finally we investigate relationships of the Fourier transform and the generalized Fourier-Feynman transform.

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Theoretical Background for the Application of the Continuous Wavelet Transform (연속웨이블렛 변환의 활용에 대한 이론적 배경)

  • Kim, Yoon-Young;Kim, Eung-Hun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.724-730
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    • 2000
  • Although there have been many investigations employing the continuous wavelet transform for the analysis of dispersive waves, they seem to lack theoretical justifications for the effectiveness of the continuous wavelet transform over other time-frequency analysis tools such as the short-time Fourier transform. The goal of this paper is to answer this question by investigating theoretically the performance of the continuous wavelet transform and the short-time Fourier transform in tracing rapidly time-varying flexural waves. As a specific example, the performance of the two transforms is compared in a problem dealing with flexural waves generated by an impact in a solid circular cylinder.

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Fingerprint Classification and Identification Using Wavelet Transform and Correlation (웨이블릿변환과 상관관계를 이용한 지문의 분류 및 인식)

  • 이석원;남부희
    • Journal of Institute of Control, Robotics and Systems
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    • 제6권5호
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    • pp.390-395
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    • 2000
  • We present a fingerprint identification algorithm using the wavelet transform and correlation. The wavelet transform is used because of its simple operation to extract fingerprint minutiaes features for fingerprint classification. We perform the rowwise 1-D wavelet transform for a $256\times256$ fingerprint image to get a $1\times256$ column vector using the Haar wavelet and repeat 1-D wavelet transform for a 1$\times$256 column vector to get a $1\times4$ feature vector. Using PNN(Probabilistic Neural Network), we select the possible candidates from the stored feature vectors for fingerprint images. For those candidates, we compute the correlation between the input binary image and the target binary image to find the most similar fingerprint image. The proposed algorithm may be the key to a low cost fingerprint identification system that can be operated on a small computer because it does not need a large memory size and much computation.

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Measurement of Mode Shape By Using A Scanning Laser Doppler Vibrometer (스캐닝 레이저 도플러 진동 측정기를 이용한 모드 측정)

  • Kang, Min-Sig
    • Proceedings of the KSME Conference
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    • 대한기계학회 2000년도 춘계학술대회논문집A
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    • pp.420-425
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    • 2000
  • When spatially dense velocity distribution is measured by a scanning laser Doppler vibrometer, the Fourier transform method provides the real and imaginary parts of the mode shapes in the form of a polynomial. However the Fourier transform method is often impractical because the independent decomposition property of cosine and sine components into real and imaginary parts, respectively, does not hold due to the leakage problem which commonly occurs in the Fourier transform of harmonic signals. To deal with this problem, a Hilbert transform method is newly proposed in this article. The proposed method is free from the leakage problem and relatively robust to tire scanning error. A simulation example is provided to verify the effectiveness of this method.

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