• Title/Summary/Keyword: 디컨벌루션

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An Image Segmentation Method for Richardson-Lucy Deconvolution Algorithm Improvement (영상 분할을 통한 Richardson-Lucy 디컨벌루션 개선 알고리듬)

  • Kim, Jeonghwan;Park, Daejun;Jeon, Jechang
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2015.11a
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    • pp.114-117
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    • 2015
  • 본 논문에서는 Non-blind 디컨벌루션 알고리듬 중 하나인 Richardson-Lucy(RL) 디컨벌루션을 영상 분할을 통해 성능을 향상시킨 알고리듬을 제안한다. RL 디컨벌루션은 영상의 크기가 커질수록 연산 양이 크게 증가한다. 따라서 크기가 큰 영상의 RL 디컨벌루션은 계산에 많은 시간을 필요로 한다. 이를 개선하기 위하여 영상을 적절한 크기로 분할하여 각각 RL 디컨벌루션을 계산한다. 또한 분할 시 생기는 왜곡을 줄이기 위해 리플 제거를 위한 알고리듬을 추가한다. 이를 통해 기존의 알고리듬보다 연산 양을 줄여 빠른 RL 디컨벌루션이 가능하도록 개선한다.

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3D gravity inversion with Euler deconvolution as a priori information (오일러 디컨벌루션을 사전정보로 이용한 3 차원 중력 역산)

  • Rim, Hyoung-Rae;Park, Yeong-Sue;Lim, Mu-Taek;Koo, Sung-Bon;Kwon, Byung-Doo
    • Geophysics and Geophysical Exploration
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    • v.10 no.1
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    • pp.44-49
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    • 2007
  • It is difficult to obtain high-resolution images by 3D gravity inversion, because the problem is extremely underdetermined - there are too many model parameters. In order to reduce the number of model parameters we propose a 3D gravity inversion scheme utilising Euler deconvolution as a priori information. The essential point of this scheme is the reduction of the nonuniqueness of solutions by restricting the inversion space with the help of Euler deconvolution. We carry out a systematic exploration of the growing body process, but only in the restricted space within a certain radius of the Euler solutions. We have tested our method with synthetic gravity data, and also applied it to a real dataset, to delineate underground cavities in a limestone area. We found that we obtained a more reasonable subsurface density image by means of this combination between the Euler solution and the inversion process.

Analysis of Defect Signals Inside Glass Fiber Reinforced Polymer Through Deconvolution of Terahertz Wave (테라헤르츠파의 디컨벌루션을 통한 유리섬유 복합재 내부 결함 신호 분석)

  • Kim, Heon-Su;Park, Dong-Woon;Kim, Sang-Il;Lee, Jong-Min;Kim, Hak-Sung
    • Composites Research
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    • v.35 no.1
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    • pp.8-12
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    • 2022
  • Analysis of defect signals inside glass fiber reinforced polymer (GFRP) was conducted through deconvolution of terahertz (THz) wave. The GFRP specimen with internal defects was manufactured and the THz signal was measured through the reflection mode of the Terahertz Time-Domain Spectroscopy (THz-TDS) system. For deconvolution of the measured THz signal, the peak position of the THz signal was amplified through Normalized Cross Correlation (NCC) of the incident and detected THz signals. The position and intensity of the amplified peak were extracted as impulse, and the extracted signal of the impulse position was removed from the THz original signal. By repeating the process, the critical impulses, which represent boundary of the specimen, were derived. The deconvolution process was verified by confirming that the original THz signal without noise can be restored through the convolution of the critical impulses and the incident signal. From the derived critical impulses, the thickness of the internal defect in the GFRP was calculated through the detection time of impulses within 15 ㎛ accuracy.

A Genetic Programming Approach to Blind Deconvolution of Noisy Blurred Images (잡음이 있고 흐릿한 영상의 블라인드 디컨벌루션을 위한 유전 프로그래밍 기법)

  • Mahmood, Muhammad Tariq;Chu, Yeon Ho;Choi, Young Kyu
    • KIPS Transactions on Software and Data Engineering
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    • v.3 no.1
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    • pp.43-48
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    • 2014
  • Usually, image deconvolution is applied as a preprocessing step in surveillance systems to reduce the effect of motion or out-of-focus blur problem. In this paper, we propose a blind-image deconvolution filtering approach based on genetic programming (GP). A numerical expression is developed using GP process for image restoration which optimally combines and exploits dependencies among features of the blurred image. In order to develop such function, first, a set of feature vectors is formed by considering a small neighborhood around each pixel. At second stage, the estimator is trained and developed through GP process that automatically selects and combines the useful feature information under a fitness criterion. The developed function is then applied to estimate the image pixel intensity of the degraded image. The performance of developed function is estimated using various degraded image sequences. Our comparative analysis highlights the effectiveness of the proposed filter.

Wavelet Transform Based Deconvolution for Improvement of Time-Resolution of A-Scan Ultrasonic Signal (A-Scan 초음파 신호의 시간분해능 향상을 위한 웨이브렛 해석 기반 디컨벌루션 기법)

  • Ha, Job;Jhang, Kyung-Young
    • Proceedings of the KSME Conference
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    • 2001.06a
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    • pp.84-89
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    • 2001
  • Ultrasonic pulse echo method comes to be difficult to apply to the multi-layered structure with very thin layer, because the echoes from the top and the bottom of the layer are overlapped. Conventionally method, deconvolution technique has been used for the decomposition of overlapped UT signals, however it has disabilities when the waveform of the transmitted signal is distorted according to the propagation. In this paper, the wavelet transform based deconvolution (WTBD) technique is proposed as a new signal processing method that can decompose the overlapped echo signals in A-Scan signal with superior performances compared to the conventional deconvolution technique. Performances of the proposed method are shown by through computer simulations using model signal with noise and are demonstrated by through experiments for the fabricated acryl rod with a thin steel plate bonded to it.

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Ray backpropagation-based ship localization (음선 역전파 기반의 선박 위치 추정)

  • Cho, Seong-il;Byun, Gihoon;Byun, Sung-Hoon;Kim, J.S.
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.4
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    • pp.196-205
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    • 2018
  • This paper presents an algorithm for passive localization of a ship by applying the ray back-propagation technique to the ship radiation noise data. The previous method [S. H. Abadi, D. Rouseff and D. R. Dowling, J. Acoust. Soc. Am. 131, 2599-2610 (2012)] estimates the position of a sound source in the near-field environment with no array tilt by using the RBD (Ray-based Blind Deconvolution) and ray back-propagation techniques. However, when there exists an array tilt, the above method leads to a large position estimation error. In order to overcome the problem, this study proposes an algorithm that estimates the position of a sound source by correcting the array tilt using the RBD and ray back-propagation techniques. The proposed algorithm was verified by using the ship noise of SAVEX15 (Shallow-water Acoustic Variability EXperiment in 2015) experimental data.

Source depth discrimination based on channel impulse response (채널 임펄스 응답을 이용한 음원 깊이 구분)

  • Cho, Seong-il;Kim, Donghyun;Kim, J.S.
    • The Journal of the Acoustical Society of Korea
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    • v.38 no.1
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    • pp.120-127
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    • 2019
  • Passive source depth discrimination has been studied for decades since the source depth can be used for discriminating whether the target is near the surface or submerged. In this thesis, an algorithm for source depth discrimination is proposed based on CIR (Channel Impulse Response) from target-radiated noise (or signal). In order to extract CIR without a known source signal, Ray-based blind deconvolution is used. Subsequently, intersections of CIR pattern, which is characterized by ray arrival time difference, is utilized for discriminating source depth. The proposed algorithm is demonstrated through numerical simulation in ocean waveguide, and verified via the experimental data.

DCT-based Regularized High-Resolution Image Reconstruction Algorithm (DCT 기반의 정규화 된 고해상도 영상 복원 알고리즘)

  • 박진열;이승현;강문기
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.8B
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    • pp.1558-1566
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    • 1999
  • While high resolution images are required for various applications, aliased low-resolution images are only available due to the physical limitations of sensors. In this paper, we propose an algorithm to reconstruct a high resolution image from multiple aliased low-resolution images, which is based on the generalized multichannel deconvolution technique. The conventional approaches are based on the discrete Fourier transform (DFT) since the aliasing effect is easily analyzed in the frequency domain. However, the useful solution may not be available in many cases, i.e., the underdetermined cases or the insufficient subpixel information cases. In order to compensate for such ill-posedness, the generalized multichannel regularization was adopted in the spatial domain. Furthermore, the usage of the discrete cosine transform instead of the DFT leads to the computationally efficient reconstruction algorithm. The validity of the proposed algorithm is both theoretically and experimentally demonstrated in this paper. It is also shown that the effect of inaccurate motion information is reduced by regularization.

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The Seismic Multipulse Deconvolution (다중펄스 방법을 이용한 디컨벌루션)

  • Shon, Howoong
    • Economic and Environmental Geology
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    • v.28 no.5
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    • pp.487-491
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    • 1995
  • The multipulse model of linear predictive coding (LPC), which has been successfully used for compressing of speech signals into an impulse excitation, is here applied to seismic data which contains multiples. Multiples are happened by successive reflection between layers and make the seismic interpretation difficult In this paper, the author applied the enhanced multipulse method to seismic traces to compress source-wavelets into spikes, and to eliminate/reduce multiples. The enhanced multipulse method which was applied to seismic traces extracted the amplitudes and locations of reflectivity function, which depicts the subsurface configuration, by iterative computation of autoregressive (AR) estimation method.

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Performance analysis on the complexity of turbo code with short frame sizes (프레임 크기가 작은 터보 코드의 복잡도에 대한 성능 분석)

  • Kim, Yeun-Goo;Ko, Young-Hoon;Kim, Nam
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.7A
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    • pp.1046-1051
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    • 1999
  • It is well known that Parallel Concatenated Convolutional Codes(turbo codes) has a good performance for long block sizes. This thesis has analyzed the performance of turbo code which is based on voice or control frames with short frame sizes in the future mobile communication system. Also, at the similar decoding complexity, the performance of turbo code and convolutional codes in the speech/control frames, and the applicability of this system are considered. As a result, turbo code in short frame sizes present the performance of a BER of $10^{-3}$ or more over 3 iterations in the future mobile communication system. However, at a BER of $10^{-3}$ , if the same complexity is considered, the performance of rate 1/2 turbo code with K = 5 is better than that of convolutional code with K = 9 at low $E_b/N_0$, and the performance of turbo code with K = 3 is superior to that of convolutional code with K = 7. Rate 1/3 turbo code with K = 3 and 5 have similar to performance of rate 1/2 turbo code.

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