• Title/Summary/Keyword: Subband

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A New Sign Subband Adaptive Filter with Improved Convergence Rate (향상된 수렴속도를 가지는 부호 부밴드 적응 필터)

  • Lee, Eun Jong;Chung, Ik Joo
    • The Journal of the Acoustical Society of Korea
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    • v.33 no.5
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    • pp.335-340
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    • 2014
  • In this paper, we propose a new sign subband adaptive filter to improve the convergence rate of the conventional sign subband adaptive filter which has been proposed to deal with colored input signal under the environment with impulsive noise. The existing sign subband adaptive filter does not increase the convergence speed by increasing the number of subband because each subband input signal is normalized by $l_2-norm$ of all of the subband input signals. We devised a new sign subband adaptive filter that normalizes each subband input signal with $l_2-norm$ of each subband input signal and increases the convergence rate by increasing the number of subband. We carried out a performance comparison of the proposed algorithm with the existing sign subband adaptive filter using a system identification model. It is shown that the proposed algorithm has faster convergence rate than the existing sign subband adaptive filter.

A Study on the sound localization system using Subband CPSP Algorithm (Subband CPSP를 이용한 음원 추적 시스템에 관한 연구)

  • 오상헌;박규식;박재현;이현정;온승엽
    • Proceedings of the IEEK Conference
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    • pp.102-105
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    • 2000
  • This paper propose new sound localization algorithm that calculates TDOA(Time Difference Of Arrival) between the two received signals via two microphone array, The proposed Subband CPSP is a development of Previous CPSP method using subband approach. It first split the received microphone signals into three frequency bands and then calculates subband CPSP with corresponding SNR weights. This type of algorithm, Subband CPSP, can provide more accurate TDOA estimation results because it limits the effects of environmental noise within each subband. To verify the performance of the proposed Subband CPSP algorithm, computer simulation was conducted and it was compared with previous CPSP method. From the both simulation results, the proposed Subband CPSP is superior to previous CPSP algorithm more than accuracy for TDOA estimation.

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A DSP Implementation of Subband Sound Localization System

  • Park, Kyusik
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.4E
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    • pp.52-60
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    • 2001
  • This paper describes real time implementation of subband sound localization system on a floating-point DSP TI TMS320C31. The system determines two dimensional location of an active speaker in a closed room environment with real noise presents. The system consists of an two microphone array connected to TI DSP hosted by PC. The implemented sound localization algorithm is Subband CPSP which is an improved version of traditional CPSP (Cross-Power Spectrum Phase) method. The algorithm first split the input speech signal into arbitrary number of subband using subband filter banks and calculate the CPSP in each subband. It then averages out the CPSP results on each subband and compute a source location estimate. The proposed algorithm has an advantage over CPSP such that it minimize the overall estimation error in source location by limiting the specific band dominant noise to that subband. As a result, it makes possible to set up a robust real time sound localization system. For real time simulation, the input speech is captured using two microphone and digitized by the DSP at sampling rate 8192 hz, 16 bit/sample. The source location is then estimated at once per second to satisfy real-time computational constraints. The performance of the proposed system is confirmed by several real time simulation of the speech at a distance of 1m, 2m, 3m with various speech source locations and it shows over 5% accuracy improvement for the source location estimation.

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TMS320C80에서의 subband decomposition을 이용한 image coding

  • 이원희;정진현
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1730-1733
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    • 1997
  • In this paper, a realization of a subband coding with TMS320C80 is studied. TMS320C80 is a multi-media processor specially designed for an image process. A main topic of this paper, as mentioned above, is an application of TMS320C80 to subband coding. Subband coding is the coding that devides full image to several subbands and encodes each subband with different coding methods. As using that methods, good image compression can be obtained. First above all, goal of this paper deals with TMS320C80 in coding still image and useds it in expending it's application to 3-D video coding.

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Block-based subband/DCT coding (블록단위 대역분할/DCT 부호화)

  • 김정권;이상욱;이충웅
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.35S no.2
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    • pp.97-105
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    • 1998
  • Subband/DCT coding has been introduced in order to transmit images of various resultions using one given image-codec, for nowadays there are various grades of quality in visual communication services. However, subband/DCT results in the increawse of multiplication number and memory size. In order to resolve this problem, we propose block-based subband/DCT coding in this paper. In block-based subband/DCT, the number of multiplications is not only reduced because we combine subband decomposistion with DCT, but the size of memory is also reduced because images can be parallel-processed block by block. We show that the number of multiplications is reduced, by analyzing the property ofblock-based subband/DCT matrix mathematically, and examine the performance of proposed coder, which adopts JPEG as backhand-coder after block-based subband/DCT.

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A Study on the Robust Sound Localization System Using Subband Filter Bank (서브밴드 필터 뱅크를 이용한 강인한 음원 추적시스템에 대한 연구)

  • 박규식;박재현;온승엽;오상헌
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.1
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    • pp.36-42
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    • 2001
  • This paper propose new sound localization algorithm that detects the sound source bearing in a closed office environment using two microphone array. The proposed Subband CPSP (Cross Power Spectrum Phase) algorithm is a development of previously Down CPSP method using subband approach. It first split the received microphone signals into subbands and then calculates subband CPSP which result in possible source bearings. This type of algorithm, Subband CPSP, can provide more robust and reliable sound localization system because it limits the effects of environmental noise within each subband. To verify the performance of the proposed Subband CPSP algorithm, a real time simulation was conducted and it was compared with previous CPSP method. From the simulation results, the proposed Subband CPSP is superior to previous CPSP algorithm more than 5% average accuracy for sound source detection.

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ECVQ for Subband Pyramid Image Coding (ECVQ 를 이용한 영상의 계층적 대역분할 부호화)

  • 이광기;김인겸;정준용;류종일;박규태
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.4
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    • pp.88-96
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    • 1994
  • In this paper, we propose a subband pyramid image coding scheme that uses ECVQ (ntropy Constrained Vector Quantizer). In subband pyramid image coding, each subband can be encoded with a coder matched to the statistics of that particular subband, and available versions of the original image at different resolution are easily obtained. ECVQ, aiming at the minimization of the distortion for a fixed entropy of the quantizer output, is well combined with the subband pyramid image coding which yields high compression ratio and good image quality. The optimum bit allocation to each subbands corresponds to the points where the individual distortion rate curves are of particular slope, weighted to the number of samples in that subband, in designing ECVQ.

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Applications and analysis on the subband nonlinear adaptive Volterra filter (부대역 비선형 Volterra 적응필터의 응용과 성능분석)

  • Yang, Yoon Gi;Byun, Hee Jung
    • Journal of IKEEE
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    • v.17 no.2
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    • pp.111-118
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    • 2013
  • In this paper, the subband nonlinear adaptive Volterra filters are introduced and its analysis are presented. From the eigenvalue analysis of the input correlation matrix, we show that the proposed subband adaptive Volterra filter has superior convergence performance as compared to the conventional one, which shows that the it can be useful for the recently proposed subband nonlinear adaptive echo canceller. Also, the optimum filter in each subband are introduced and verified from the computer simulations.

Subband Adaptive Algorithm for Convex Combination of LMS based Transversal Filters (LMS기반 트랜스버설 필터의 컨벡스조합을 위한 부밴드 적응알고리즘)

  • Sohn, Sang-Wook;Lee, Kyeong-Pyo;Choi, Hun;Bae, Hyeon-Deok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.1
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    • pp.133-139
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    • 2013
  • Convex combination of two adaptive filters is an efficient method to improve adaptive filter performances. In this paper, a subband convex combination method of two adaptive filters for fast convergence rate in the transient state and low steady state error is presented. The cost function of mixing parameter for a subband convex combination is defined, and from this, the coefficient update equation is derived. Steady state analysis is used to prove the stability of the subband convex combination. Some simulation examples in system identification scenario show the validity of the subband convex combination schemes.

On Using the Human Visual System Model for Subband Coding (시각 시스템 모델을 이용한 Subband 코딩)

  • 박용철;김근숙;차일환;윤대희
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.27 no.6
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    • pp.937-943
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    • 1990
  • In this paper, a subband coding scheme using the human visual system(HVS) model for encoding monochrome images is proposed to produce perceptually higher quality images compared with the regular subband coding scheme. The proposed approach first transforms the intensity image to the density image by a point nonlinear transformation. A frequency band dexomposition of the density image is carried out by means of 2-D seaprable quadrature mirror filters, which split the density image spectrum into 16 equall rate subbands. Bits are allocated among the subbands to minimize the weighted mean squar error (WMSE) for differential pulse code modulation(DPCM) coding of the subbands. The weight for each subband is calculated from the modulation transfer function (MTF) of the HVS model at corresponding frequencies. The performances of the proposed approach are evaluated for 256 * 256 monochrome images at the bit rates of 0.5, 0.75 and 1.0 bita per pixel. Computer simulation results indicate that using the HVS model yields more pleasing reconstructed images than regular subband coding approach which does not use HVS model.

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