• Title, Summary, Keyword: Quantization Model

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DZDC Coefficient Distributions for P-Frames in H.264/AVC

  • Wu, Wei;Song, Bin
    • ETRI Journal
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    • v.33 no.5
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    • pp.814-817
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    • 2011
  • In this letter, the distributions of direct current (DC) coefficients for P-frames in H.264/AVC are analyzed, and the distortion model of the Gaussian source under the quantization of the dead-zone plus-uniform threshold quantization with uniform reconstruction quantizer is derived. Experimental results show that the DC coefficients of P-frames are best approximated by the Laplacian distribution and the Gaussian distribution at small quantization step sizes and at large quantization step sizes, respectively.

The effects of scaling factors and quantization in sensors on free motion of teleoperation system

  • Hwang, Dal-Yeon;Cho, SangKyu;Park, Sanguk
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1512-1515
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    • 1997
  • One of the advantages of master-slave teleoperation is scaling concept such as position scaling, force scaling Meanuhile, lots of quantization effects are generated from position and force sensors in the master and slave manipulator. In this paper, to show the output error caused by the quantizaion effects from the position sensor and position scaling factor, simulation is done for free motion without contact in slave side. Transfer functiion model in which the quantization effect is assumed to be a disturbance input to the system is derived. Model shows that Jacobian, scaling factors, and controller affect the output by quantization effects form esnsors. One dof master and slave are used for simulation. In our study, the higher sensor resolution decreases the output error form quantization. Scaling factors can amplify the quantizatiion effects form the sensors in master and slave manipulators.

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Quantization of LPC Coefficients Using a Multi-frame AR-model (Multi-frame AR model을 이용한 LPC 계수 양자화)

  • Jung, Won-Jin;Kim, Moo-Young
    • The Journal of the Acoustical Society of Korea
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    • v.31 no.2
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    • pp.93-99
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    • 2012
  • For speech coding, a vocal tract is modeled using Linear Predictive Coding (LPC) coefficients. The LPC coefficients are typically transformed to Line Spectral Frequency (LSF) parameters which are advantageous for linear interpolation and quantization. If multidimensional LSF data are quantized directly using Vector-Quantization (VQ), high rate-distortion performance can be obtained by fully utilizing intra-frame correlation. In practice, since this direct VQ system cannot be used due to high computational complexity and memory requirement, Split VQ (SVQ) is used where a multidimensional vector is split into multilple sub-vectors for quantization. The LSF parameters also have high inter-frame correlation, and thus Predictive SVQ (PSVQ) is utilized. PSVQ provides better rate-distortion performance than SVQ. In this paper, to implement the optimal predictors in PSVQ for voice storage devices, we propose Multi-Frame AR-model based SVQ (MF-AR-SVQ) that considers the inter-frame correlations with multiple previous frames. Compared with conventional PSVQ, the proposed MF-AR-SVQ provides 1 bit gain in terms of spectral distortion without significant increase in complexity and memory requirement.

Quantization error model of signal converter in strapdown inertial navigation system (스트랩다운 관성항법장치의 신호변환기 양자화 오차모델)

  • 정태호;송기원
    • 제어로봇시스템학회:학술대회논문집
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    • pp.131-135
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    • 1991
  • A quantization error model is suggested for analog to frequency(A/F) converter in strapdown inertial navigation system(SDINS),which is characterized by some white noise exciting the state variables. Also, effects on the performance of SDINS by analog to digital(A/D) converter and A/F converter are analyzed and compared via covariance simulation. As a result, A/F converter turns out to be superior to the A/D converter with respect to the induced navigation error and the difficulty in circuit realization. The quantization error model developed in this paper appears to be useful for optimal filter design.

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Quantization Modeling of Intra Frame for Rate Control (비트율 제어를 위한 인트라 프레임 양자화 모델링)

  • Park, Sang-Hyun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.9 no.10
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    • pp.1207-1214
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    • 2014
  • The first frame of a GOP is encoded in intra mode which generates a larger number of bits. In addition, the first frame is used for the inter mode encoding of the following frames. Thus the encoding results of the intra frame affects the first frame as well as the following frames. Traditionally, the quantization parameter for an intra frame is determined only depending on the bpp not considering the characteristics of the intra frame. For accurate intra frame encoding, we should consider not only bpp but also the complexity of the video sequence and the output bandwidth. In this paper, we propose a real-time quantization model which is used to calculate the quantization parameter for an intra frame encoding based on the investigation on the characteristics of a GOP. It is shown by experimental results that the proposed quantization model captures the characteristics of an intra frame effectively and the proposed method for model parameters accurately estimates the real values.

Improved Channel Level Difference Quantization for Spatial Audio Coding

  • Kim, Kwang-Ki;Beack, Seung-Kwon;Seo, Jeong-Il;Jang, Dae-Young;Hahn, Min-Soo
    • ETRI Journal
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    • v.29 no.1
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    • pp.99-102
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    • 2007
  • The channel level difference (CLD) is a main parameter in the reference model 0 (RM0) for MPEG Surround. Nevertheless, the CLD quantization method in the RM0 has problems such as the lack of theoretical background and inappropriate quantization levels. In this letter, a new CLD quantization method is proposed based on the virtual source location information which has strength in the quantization process. From experimental results, it is confirmed that the proposed scheme greatly reduces the quantization distortions measured in dB and degrees without any additional complexity.

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Event-Triggered Model Predictive Control for Continuous T-S fuzzy Systems with Input Quantization (양자화 입력을 고려한 연속시간 T-S 퍼지 시스템을 위한 이벤트 트리거 모델예측제어)

  • Kwon, Wookyong;Lee, Sangmoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.9
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    • pp.1364-1372
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    • 2017
  • In this paper, a problem of event-triggered model predictive control is investigated for continuous-time Takagi-Sugeno (T-S) fuzzy systems with input quantization. To efficiently utilize network resources, event-trigger is employed, which transmits limited signals satisfying the condition that the measurement of errors is over the ratio of a certain level. Considering sampling and quantization, continuous Takagi-Sugeno (T-S) fuzzy systems are regarded as a sector bounded continuous-time T-S fuzzy systems with input delay. Then, a model predictive controller (MPC) based on parallel distributed compensation (PDC) is designed to optimally stabilize the closed loop systems. The proposed MPC optimize the objective function over infinite horizon, which can be easily calculated and implemented solving linear matrix inequalities (LMIs) for every event-triggered time. The validity and effectiveness are shown that the event triggered MPC can stabilize well the systems with even smaller average sampling rate and limited actuator signal guaranteeing optimal performances through the numerical example.

A piecewise affine approximation of sigmoid activation functions in multi-layered perceptrons and a comparison with a quantization scheme (다중계층 퍼셉트론 내 Sigmoid 활성함수의 구간 선형 근사와 양자화 근사와의 비교)

  • 윤병문;신요안
    • Journal of the Korean Institute of Telematics and Electronics C
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    • v.35C no.2
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    • pp.56-64
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    • 1998
  • Multi-layered perceptrons that are a nonlinear neural network model, have been widely used for various applications mainly thanks to good function approximation capability for nonlinear fuctions. However, for digital hardware implementation of the multi-layere perceptrons, the quantization scheme using "look-up tables (LUTs)" is commonly employed to handle nonlinear signmoid activation functions in the neworks, and thus requires large amount of storage to prevent unacceptable quantization errors. This paper is concerned with a new effective methodology for digital hardware implementation of multi-layered perceptrons, and proposes a "piecewise affine approximation" method in which input domain is divided into (small number of) sub-intervals and nonlinear sigmoid function is linearly approximated within each sub-interval. Using the proposed method, we develop an expression and an error backpropagation type learning algorithm for a multi-layered perceptron, and compare the performance with the quantization method through Monte Carlo simulations on XOR problems. Simulation results show that, in terms of learning convergece, the proposed method with a small number of sub-intervals significantly outperforms the quantization method with a very large storage requirement. We expect from these results that the proposed method can be utilized in digital system implementation to significantly reduce the storage requirement, quantization error, and learning time of the quantization method.quantization method.

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Optimum design of two-dimensional subband filter banks using vector quantizer (벡터양자기를 사용한 최적의 이차원 부대역필터의 구현)

  • Jonghong Shin;Innho Jee
    • Proceedings of the IEEK Conference
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    • pp.667-670
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    • 2000
  • This paper provides a heuristic theory for modeling and analysis of vector quantization effects in 2-dimensional subband filter banks. This model is used as the basis for optimal filter bank design. The scalar non-linear gain-plus-additive noise quantization model can be used to represent each vector quantizer in 2-band subband codec. The validity and accuracy and of this analytic model is confirmed by comparing the calculated model quantization errors with actual simulation of the optimum LBG vector quantizer. Numerical design examples for the optimum separable paraunitary filter banks are suggested in this paper.

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Model Parameter-based Rate Control Algorithm for Constant Quality Real-Time Video Coding (실시간 부호화를 위한 모델 파라미터 기반 일정 화질 비트율 제어 기법)

  • Jeong, Jin-Woo;Cho, Kyung-Min;Choe, Yoon-Sik
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.3
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    • pp.93-102
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    • 2008
  • In this paper, we propose a rate control algorithm for constant quality real time video coding. To achieve constant quality, previous algorithm exploit mean absolute of difference(MAD) as measure of frame complexity. However, if scene is abruptly changed or if quantization parameter is not constant, encoder produces various output bits with same MAD. Therefore we know that MAD does not appropriately reflect characteristic of frame. To solve this problem, we exploit model parameter as measure of frame complexity. Because model parameter means slope between output bits and MAD, it reflects correctly complexity of frame. And because previous model, R-MAD model, is not considered quantization parameter, as quantization parameter increases or decreases, model parameter of frame also vary. So model parameter obtained using previous model cannot reflect internal characteristic of video. We solve this problem using proposed model, which is considered quantization parameter. Experiment results show that our algorithm provide better performance, in terms of quality smoothness than previous algorithm. Especially, when scene is abruptly changed, our algorithm alleviates quality drop.