• Title, Summary, Keyword: Quantization Model

Search Result 198, Processing Time 0.036 seconds

Floating-Poing Quantization Error Analysis in Subband Codes System

  • Park, Kyu-Sik
    • The Journal of the Acoustical Society of Korea
    • /
    • v.16 no.1E
    • /
    • pp.41-48
    • /
    • 1997
  • The very purpose of subband codec is the attainment of data rate compression through the use of quantizer and optimum bit allocation for each decimated signal. Yet the question of floating-point quantization effects in subband codec has received scant attention. There has been no direct focus on the analysis of quantization errors, nor on design with quantization errors embedded explicitly in the criterion. This paper provides a rigorous theory for the modelling, analysis and optimum design of the general M-band subband codec in the presence of the floating-point quantization noise. The floating-point quantizers are embedded into the codec structure by its equivalent multiplicative noise model. We then decompose the analysis and synthesis subband filter banks of the codec into the polyphase form and construct an equivalent time-invariant structure to compute exact expression for the mean square quantization error in the reconstructed an equivalent time-invariant structure to compute exact expression for the mean square quantization error in the reconstructed output. The optimum design criteria of the subband codec is given to the design of the analysis/synthesis filter bank and the floating-point quantizer to minimize the output mean square error. Specific optimum design examples are developed with two types of filter of filter banks-orthonormal and biorthogonal filter bank, along with their perpormance analysis.

  • PDF

Histogram Equalization Based Color Space Quantization for the Enhancement of Mean-Shift Tracking Algorithm (실시간 평균 이동 추적 알고리즘의 성능 개선을 위한 히스토그램 평활화 기반 색-공간 양자화 기법)

  • Choi, Jangwon;Choe, Yoonsik;Kim, Yong-Goo
    • Journal of Broadcast Engineering
    • /
    • v.19 no.3
    • /
    • pp.329-341
    • /
    • 2014
  • Kernel-based mean-shift object tracking has gained more interests nowadays, with the aid of its feasibility of reliable real-time implementation of object tracking. This algorithm calculates the best mean-shift vector based on the color histogram similarity between target model and target candidate models, where the color histograms are usually produced after uniform color-space quantization for the implementation of real-time tracker. However, when the image of target model has a reduced contrast, such uniform quantization produces the histogram model having large values only for a few histogram bins, resulting in a reduced accuracy of similarity comparison. To solve this problem, a non-uniform quantization algorithm has been proposed, but it is hard to apply to real-time tracking applications due to its high complexity. Therefore, this paper proposes a fast non-uniform color-space quantization method using the histogram equalization, providing an adjusted histogram distribution such that the bins of target model histogram have as many meaningful values as possible. Using the proposed method, the number of bins involved in similarity comparison has been increased, resulting in an enhanced accuracy of the proposed mean-shift tracker. Simulations with various test videos demonstrate the proposed algorithm provides similar or better tracking results to the previous non-uniform quantization scheme with significantly reduced computation complexity.

Novel Rate Control Scheme for Low Delay Video Coding of HEVC

  • Wu, Wei;Liu, Jiong;Feng, Lei
    • ETRI Journal
    • /
    • v.38 no.1
    • /
    • pp.185-194
    • /
    • 2016
  • In this paper, a novel rate control scheme for low delay video coding of High Efficiency Video Coding (HEVC) is proposed. The proposed scheme is developed by considering a new temporal prediction structure of HEVC. In the proposed scheme, the relationship between bit rate and quantization step is exploited firstly to formulate an accurate quadratic rate-quantization (R-Q) model. Secondly, a method of determining the quantization parameters (QPs) for the first frames within a group of pictures is proposed. Thirdly, an accurate frame-level bit allocation method is proposed for HEVC. Finally, based on the proposed R-Q model and the target bit allocated for the frame, the QPs are predicted for coding tree units by using rate-distortion (R-D) optimization. We compare our scheme against that of three other state-of-the-art rate control schemes. Experimental results show that the proposed rate control scheme can increase the Bjøntegaard delta peak signal-to-noise ratio by 0.65 dB and 0.09 dB on average compared with the JCTVC-I0094 and JCTVC-M0036 schemes, respectively, both of which have been implemented in an HEVC test model encoder; furthermore, the proposed scheme achieves a similar R-D performance to Wang's scheme, as well as obtaining the smallest bit rate mismatch error of all the schemes.

Under the fading channel environment, performance evaluation of AF CR loop Due to the quantization effect (페이딩 채널 환경하에서의 양자화 특성에 의한 AF CR loop의 성능평가)

  • 송재철;이경하;김선형;최형진
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.21 no.3
    • /
    • pp.737-746
    • /
    • 1996
  • In this paper, we present simulation result of quantization effects about a new Angular From Carrier Recovery Loop(AF CR loop) for PSK modulation technique. AF CR loop includes detected angle symbol and Multi Level hardimiter. In general, detected angle is used in dtermining symbol. Because detected angle is used to make an error signal of phase detector output, hardware implementation of AF CR loop is simpler than that of other loops. Before hardware implementation of AF CR loop, the result due to quantization effect should be investigated. In order to confirm quntization effect of AF CR loop, we evaluate performance of this loop by Monte-Carlosimulation method. Under both in the AWGN and Jake's fading noise channel environments, we confirmed the characteristics of AF CR loop in terms of RMS jitter due to quntization effect. Differential APSK modulation schemeis used in this paper. Especially, Jake's fading channel is used as a channel model and also AGC(Automatic Gain Control) is used in the overall process of performance evaluation. We obtained the resonable result of quantization effect about AF CR loop. With the result of performanceevaluation based on quantization effects, we can expect to operate AF CRloop under the fading channel environments reasonably well.

  • PDF

Optimal Realization of a State-Space Digital Filter Using Singular Value Decomposition (특이치 분해를 이용한 상태 공간 디지틀 필터의 최적 실현)

  • 문용선;박종안;김재민
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.15 no.2
    • /
    • pp.155-165
    • /
    • 1990
  • The problem of quantization errors in digital filter design arises because of the practical necessity due to finite wordlength implementation. These errors are classified into coefficient quantization error and roung off error. In this paper, in order to analyze and reduce these errors, minimum ceefficient quantization realization is directly derived form impulse responese design specification. And using the equivalent transform relation between minimum coefficient quantization error and minimum roundoff error realizations, we synthesize an optimal realization state-space digital filter. This technique is analyzed by the simulation of an approximated 3rd model, which shows that it is superior to direct or cascade state-space digital filter in quantization errors.

  • PDF

Trade-off between Model Complexity and Performance in Intra-frame Predictive Vector Quantization of Wideband Speech (광대역 음성에 대한 프레임내 잔차 벡터 양자화에 있어서 모델 복잡도와 성능 사이의 교환관계)

  • Song, Geun-Bae;Hahn, Hern-Soo
    • The Journal of Korea Robotics Society
    • /
    • v.5 no.1
    • /
    • pp.70-76
    • /
    • 2010
  • This paper addresses a design issue of "model complexity and performance trade-off" in the application of bandwidth extension (BWE) methods to the intra-frame predictivevector quantization problem of wideband speech. It discusses model-based linear and non-linear prediction methods and presents a comparative study of them in terms of prediction gain. Through experimentation, the general trend of saturation in performance (with the increase in model complexity) is observed. However, specifically, it is also observed that there is no significant difference between HMM and GMM-based BWE functions.

Digital Implementation of Backing up control of Truck-trailer type Mobile Robots (트럭-트레일러 타입의 모바일로봇을 위한 귀환 제어기 설계)

  • Ku, Ja-Yl;Park, Chang-Woo
    • 전자공학회논문지 IE
    • /
    • v.46 no.2
    • /
    • pp.33-45
    • /
    • 2009
  • In this paper, the implementation of the backward movement control of a truck-trailer type mobile robot using fuzzy model based control scheme considering the practical constraints, computing time-delay and quantization is presented. We propose the fuzzy feedback controller whose output is delayed with unit sampling period and predicted. The analysis and the design problem considering the computing time-delay become very easy because the proposed controller is syncronized with the sampling time. Also, the stability analysis is made when the quantization exists in the implementation of the fuzzy control architectures and it is shown that if the trivial solution of the fuzzy control system without quantization is asymptotically stable, then the solutions of the fuzzy control system with quantization are uniformly ultimately bounded. The experimental results are shown to verify the effectiveness of the proposed scheme.

Adaptive Skin Segmentation based on Region Histogram of Color Quantization Map (칼라 양자화 맵의 영역 히스토그램에 기반한 조명 적응적 피부색 영역 분할)

  • Cho, Seong-Sik;Bae, Jung-Tae;Lee, Seong-Whan
    • Journal of KIISE:Software and Applications
    • /
    • v.36 no.1
    • /
    • pp.54-61
    • /
    • 2009
  • This paper proposes a skin segmentation method based on region histograms of the color quantization map. First, we make a quantization map of the image using the JSEG algorithm and detect the skin pixel. For the skin region detection, the similar neighboring regions are set by its similarity of the size and location between the previous frame and the present frame from the each region of the color quantization map. Then we compare the similarity of histogram between the color distributions of each quantized region and the skin color model using the histogram distance. We select the skin region by the threshold value calculated automatically. The skin model is updated by the skin color information from the selected result. The proposed algorithm was compared with previous algorithms on the ECHO database and the continuous images captured under time varying illumination for adaptation test. Our approach shows better performance than previous approaches on skin color segmentation and adaptation to varying illumination.

Development of a Robust Multiple Audio Watermarking Using Improved Quantization Index Modulation and Support Vector Machine (개선된 QIM과 SVM을 이용한 공격에 강인한 다중 오디오 워터마킹 알고리즘 개발)

  • Seo, Ye-Jin;Cho, San-Gjin;Chong, Ui-Pil
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.16 no.2
    • /
    • pp.63-68
    • /
    • 2015
  • This paper proposes a robust multiple audio watermarking algorithm using improved QIM(quantization index modulation) with adaptive stepsize for different signal power and SVM(support vector machine) decoding model. The proposed algorithm embeds watermarks into both frequency magnitude response and frequency phase response using QIM. This multiple embedding method can achieve a complementary robustness. The SVM decoding model can improve detection rate when it is not sure whether the extracted data are the watermarks or not. To evaluate robustness, 11 attacks are employed. Consequently, the proposed algorithm outperforms previous multiple watermarking algorithm, which is identical to the proposed one but without SVM decoding model, in PSNR and BER. It is noticeable that the proposed algorithm achieves improvements of maximum PSNR 7dB and BER 10%.

Adaptive Digital Watermarking Based on Wavelet Transform Using Successive Subband Quantization and Perceptual Model

  • Kim, Ju-Young;Kwon, Seong-geun;Hwang, Hee-Chul;Kwon, Ki-Ryong;Kim, Duk-Gyoo
    • Proceedings of the IEEK Conference
    • /
    • /
    • pp.1240-1243
    • /
    • 2002
  • In this paper, we propose an adaptive digital image watermarking algorithm using successive subband quantization (SSQ) and perceptual model based on wavelet domain. The watermark is embedded into the perceptually significant coefficients (PSCs) of image. The PSCs in the baseband are selected according to the amplitude of the coefficients and the high frequency subbands are selected by SSQ. To embed the watermark, we use perceptual model. The perceptual model is based on the computation of the noise visibility function (NVF) and embed at the texture and edge region stronger embedded watermarks.

  • PDF