• Title/Summary/Keyword: Digital fourier transform

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Computer Application to ECG Signal Processing

  • Okajima, Mitsuharu
    • Journal of Biomedical Engineering Research
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    • v.6 no.2
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    • pp.13-14
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    • 1985
  • We have developed a microprogramir!able signal processor for real-time ultrasonic signal processing. Processing speed was increased by the parallelism in horizontal microprogram using 104bits microcode and the Pipelined architecture. Control unit of the signal processor was designed by microprogrammed architec- ture and writable control store (WCS) which was interfaced with host computer, APPLE- ll . This enables the processor to develop and simulate various digital signal processing algorithms. The performance of the processor was evaluated by the Fast Fourier Transform (FFT) program. The execution time to perform 16 bit 1024 points complex FF7, radix-2 DIT algorithm, was about 175 msec with IMHz master Clock. We can use this processor to Bevelop more efficient signal processing algorithms on the biological signal processing.

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Analysis of Homomorphic Filtered Remotely Sensed Imagery and Multiple Geophysical Images

  • Ryu Hee-Young;Lee Kiwon;Kwon Byung-Doo
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.237-240
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    • 2004
  • In this study, the digital image processing with image enhancement based on homomorphic filtering was performed using geophysical imaging data such as gravity, magnetic data and sub-scenes of satellite images such as LANDSAT, IKONOS, and KOMPSAT. Windows application program for executing homomorphic filtering was designed and newly implemented. In general, homomorphic filtering is technique that is based on Fourier transform, which enhances the contrast of image by removing the low frequencies and amplifying the high frequencies in frequency domain. We can enhance the image selectively using homomorphic filtering as compared with the existing method, which enhance the image totally. Through several experiment using remotely sensed imagery and geophysical image with this program, it is concluded that homomorphic filtering is more effective to reveal distinct characteristics for some complicated and multi-associated features on image data.

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Noise reduction system using time-delay neural network (시간지연 신경회로망을 이용한 잡음제거 시스템)

  • Choi Jae-Seung
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.3 s.303
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    • pp.121-128
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    • 2005
  • On the research field for speech signal, neural network mainly uses for the category classification in speech recognition and applies to signal processing. Accordingly, this paper proposes a noise reduction system using a time-delay neural network, which implements the mapping from the space of speech signal degraded by noise to the space of clean speech signal. It is confirmed that this method is effective for speech degraded not only by white noise but also by colored noise using the noise reduction system, which restores the amplitude component of fast Fourier transform.

The Design of Digital Protection Relay under Harmonic Distortion (고조파 왜곡을 고려한 디지털 보호계전기의 설계)

  • Kim, Beung-Jin;Cho, Chul-Hee;Lee, Bo-In;Kim, Jung-Han
    • Proceedings of the KIEE Conference
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    • 2002.07a
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    • pp.566-567
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    • 2002
  • In this study, the measurement part in which the Fast Fourier Transform module and orthogonal filter are included is proposed. Protection relay should has a high precision and concurrently real-time response. Because FFT routine give micro-processor heavy burden and orthogonal filter reduces precision, both FFT module and orthogonal filter are designed to have different sampling frequency.

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Design of Photo-Detector for Particle Sizer Using Laser Diffraction (레이저 회절성에 의한 입자 크기의 계측을 위한 센서 설계)

  • Nam, Boo-Hee;Kang, Sung-Gui;Yu, Tae-U;Bang, Byeong-Ryeol;Jee, Gyu-ln
    • Proceedings of the KIEE Conference
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    • 1992.07a
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    • pp.437-440
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    • 1992
  • We design a multi-element photo-detector to measure the size of particles using the diffracted light energy distribution. The light energy that is scattered by particles in the collimated laser beam is collected by the Fourier transform lens and directed to the multi-semicircular concentric annular detecters. The scattered profile measured by the photodetector is sampled by a 32 channel analog-to-digital converter. A nonnegative least squares analysis translates the light energy distribution into the corresponding unique particle size distribution.

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3D Reconstruction Method for 3D Engraving Systems (3D 조각가공 시스템을 위한 3 차원 복원 방법)

  • Lee, Won-Seck;Chung, Sung-Chong
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1204-1209
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    • 2008
  • Design is important in the IT, digital appliance, and auto industries. Aesthetic and art images are being applied for better design satisfaction of the products. Various artistic image patterns are used to satisfy demand of design, but it takes much lead-time and effort to implement them for making dies and molds. In this paper, a hybrid reverse engineering method generating accurate 3D engraving models from 2D art images is proposed through image processing, 3D reconstruction, and NURBS interpolation methods. In order to generate the 3D model from the 2D artistic image, cloud points with z-depth are extracted according to intensity values of the image. An adaptive median filter and harmonic filter are used to obtain the intensity values accurately. NURBS surfaces are generated through the interpolation of the cloud points. Performance of the developed system is to be confirmed through the realization of Mona Lisa and Golden Gate Bridge.

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Real Time W-band FMCW Distance Measuring Devices Using TMS320C6701 DSP (TMS320C6701 DSP를 이용한 실시간 W-대역 FMCW 거리측정장치)

  • Lee, Chang-Won
    • Journal of the Korea Institute of Military Science and Technology
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    • v.9 no.1 s.24
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    • pp.109-116
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    • 2006
  • This paper presents a real time distance measuring device using a W-band linear frequency modulated continuous wave(FMCW) radar and TMS320C6701 digital signal processor(DSP). We used FFT operation for measuring distance with the beat signals and the results of FFT could be converted to distance with ease. We presented how to implement a real time miniaturized hardware system including network protocols using a single DSP core. Also how to control the modulation signal of FMCW system to compensate the VCO nonlinearity using the Time Gating control of DSP is presented. We have shown that the proposed system has good performances for measuring distance in real time via outdoor environment experiments.

A Study on the Bit-slice Signal Processor for the Biological Signal Processing (생체 신호처리용 Bit-slice Signal Processor에 관한 연구)

  • Kim, Yeong-Ho;Kim, Dong-Rok;Min, Byeong-Gu
    • Journal of Biomedical Engineering Research
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    • v.6 no.2
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    • pp.15-22
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    • 1985
  • We have developed a microprogramir!able signal processor for real-time ultrasonic signal processing. Processing speed was increased by the parallelism in horizontal microprogram using 104bits microcode and the Pipelined architecture. Control unit of the signal processor was designed by microprogrammed architec- ture and writable control store (WCS) which was interfaced with host computer, APPLE- ll . This enables the processor to develop and simulate various digital signal processing algorithms. The performance of the processor was evaluated by the Fast Fourier Transform (FFT) program. The execution time to perform 16 bit 1024 points complex FF7, radix-2 DIT algorithm, was about 175 msec with IMHz master Clock. We can use this processor to Bevelop more efficient signal processing algorithms on the biological signal processing.

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Introduction to the Spectrum and Spectrogram (스팩트럼과 스팩트로그램의 이해)

  • Jin, Sung-Min
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.19 no.2
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    • pp.101-106
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    • 2008
  • The speech signal has been put into a form suitable for storage and analysis by computer, several different operation can be performed. Filtering, sampling and quantization are the basic operation in digiting a speech signal. The waveform can be displayed, measured and even edited, and spectra can be computed using methods such as the Fast Fourier Transform (FFT), Linear predictive Coding (LPC), Cepstrum and filtering. The digitized signal also can be used to generate spectrograms. The spectrograph provide major advantages to the study of speech. So, author introduces the basic techniques for the acoustic recording, digital signal processing and the principles of spectrum and spectrogram.

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A Study on the Digital Distance Relaying Algorithm based on Arithmetic Fourier Transform Filter (산술퓨리에변환 필터에 의한 디지털 거리계전알고리즘에 관한 연구)

  • Park, Kyu-Hyun;Lee, Gi-Won;Park, Chul-Won;Kim, Chul-Hwan;Shin, Myong-Chul
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.471-475
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    • 1995
  • This paper deals with the aliasing problem minimized by using an analog low-pass prefilter have a sampling frequency of 18000 Hz is designed and describes to extract their fundamental frequency components by AFT filter. And them distance relaying algorithm based AFT filter is computational simple, good frequency response and fast convergence in calculation of system apparant impedance. We performed off-line simulation using data from EMTP.

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