• Title, Summary, Keyword: Quantization Model

Search Result 198, Processing Time 0.036 seconds

Coding Unit-level Multi-loop Encoding Method based on JND for Perceptual Coding (JND 모델을 사용한 코딩 유닛 레벨 멀티-루프 인코딩 기반의 비디오 압축 방법)

  • Lim, Woong;Sim, Donggyu
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.52 no.5
    • /
    • pp.147-154
    • /
    • 2015
  • In this paper, we employed a model which defines the sensitivity according to the background luminance, so called JND (Just Noticeable Difference), and applied to the video coding. The proposed method finds out the maximum possible quantization parameter for the current unit based on the threshold of JND model and reduce the bitrate with similar perceptual quality. It selects the higher quantization parameter and reduce the bitrate when the reconstructed signal which is coded with higher quantization parameter is in a range of allowance based on the JND threshold, i.e. the signal has the similar perceptual quality compared to that is coded with the initial quantization parameter. The proposed algorithm was implemented on HM16.0, which is a reference software of the latest video coding standard HEVC (High Efficiency Video Coding) and the coding performance was evaluated. Compared to HM16.0, the proposed algorithm achieved maximum 20.21% and 6.18% of average bitrate reduction with the similar perceptual quality.

3-dimensional Mesh Model Coding Using Predictive Residual Vector Quantization (예측 잉여신호 벡터 양자화를 이용한 3차원 메시 모델 부호화)

  • 최진수;이명호;안치득
    • Journal of Broadcast Engineering
    • /
    • v.2 no.2
    • /
    • pp.136-145
    • /
    • 1997
  • As a 3D mesh model consists of a lot of vertices and polygons and each vertex position is represented by three 32 bit floating-point numbers in a 3D coordinate, the amount of data needed for representing the model is very excessive. Thus, in order to store and/or transmit the 3D model efficiently, a 3D model compression is necessarily required. In this paper, a 3D model compression method using PRVQ (predictive residual vector quantization) is proposed. Its underlying idea is based on the characteristics such as high correlation between the neighboring vertex positions and the vectorial property inherent to a vertex position. Experimental results show that the proposed method obtains higher compression ratio than that of the existing methods and has the advantage of being capable of transmitting the vertex position data progressively.

  • PDF

MPEG-2 Bit-Rate Control for Video Sequence Editing using Dynamic Macroblock Bit Assignment (압축 비디오시퀀스 편집을 위한 동적 매크로블럭 비트할당 MPEG-2 비트율 제어)

  • Kim, Ju-Do;Lee, Keun-Young
    • Journal of the Korean Institute of Telematics and Electronics S
    • /
    • v.35S no.9
    • /
    • pp.63-69
    • /
    • 1998
  • In this paper, we propose a new Bit-Rate control algorithm based on bit usage matching to substitute encoded GOP(s) for new GOP(s) in MPEG-2 bitstream. It iteratively encodes current picture according to quantization value of previous picture and records bit-usage of each slice until nearly target bits are used. With target bits falling in two output bits, quantization value of slice should be changed to alleviate output bit error. We use recorded bit-usage information to decide which slices should be encoded with one quantization value and others with another. As every macroblock has different activity, we change macroblock quantization value using slice quantization value and activity value. The simulation results demonstrate that the fluctuation of the output bits can be kept within few-several tens of bits while maintaining the quality of the reconstructed pictures at a relatively stable level.

  • PDF

Adaptive Watermarking Using Successive Subband Quantization and Perceptual Model Based on Mukiwavelet Transform (멀티웨이브릿 변환 기반에서 연속 부대역 양자화 및 지각 모델을 이용한 적응 워터마킹 기술)

  • 권기룡;강균호;조영웅;문광석;이준재
    • Proceedings of the IEEK Conference
    • /
    • /
    • pp.121-124
    • /
    • 2002
  • This paper presents an adaptive digital image watermarking scheme that uses successive subband quantization (SSQ) and perceptual modeling. Our approach performs a multiwavelet transform to determine the local image properties optimal and the watermark embedding location. The multiwavelet used in this paper is the DGHM multiwavelet with approximation order 2 to reduce artifacts in the reconstructed image. A watermark is embedded into the perceptually significant coefficients (PSC) of the image in each subband. The PSCs in high frequency subbands are selected by setting the thresholds to one half of the largest coefficient in each subband. After the PSCs in each subband are selected, a perceptual model is combined with a stochastic approach based on the noise visibility function to produce the final watermark.

  • PDF

Bearing Fault Diagnosis Using Automaton through Quantization of Vibration Signals (진동신호 양자화에 의한 거동반응을 이용한 베어링 고장진단)

  • Kim, Do-Hyun;Choi, Yeon-Sun
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.16 no.5
    • /
    • pp.495-502
    • /
    • 2006
  • A fault diagnosis method is developed in this study using automaton through quantization of vibration signals for normal and faulty conditions, respectively. Automaton is a kind of qualitative model which describes the system behaviour at the level of abstraction. The system behavior was extracted from the probability of the output sequence of vibration signals. The sequence was made as vibration levels by reconstructing the originally measured vibration signals. As an example, a fault diagnosis for the bearing of ATM machine was done, which detected the bearing fault with confident level compared to any other existing methods of kurtosis or spectrum analysis.

Motion Recognition of Smartphone using Sensor Data (센서 정보를 활용한 스마트폰 모션 인식)

  • Lee, Yong Cheol;Lee, Chil Woo
    • Journal of Korea Multimedia Society
    • /
    • v.17 no.12
    • /
    • pp.1437-1445
    • /
    • 2014
  • A smartphone has very limited input methods regardless of its various functions. In this respect, it is one alternative that sensor motion recognition can make intuitive and various user interface. In this paper, we recognize user's motion using acceleration sensor, magnetic field sensor, and gyro sensor in smartphone. We try to reduce sensing error by gradient descent algorithm because in single sensor it is hard to obtain correct data. And we apply vector quantization by conversion of rotation displacement to spherical coordinate system for elevated recognition rate and recognition of small motion. After vector quantization process, we recognize motion using HMM(Hidden Markov Model).

PSNR-based Initial QP Determination for Low Bit Rate Video Coding

  • Park, Sang-Hyun
    • Journal of information and communication convergence engineering
    • /
    • v.10 no.3
    • /
    • pp.315-320
    • /
    • 2012
  • In H.264/AVC, the first frame of a group of pictures (GOP) is encoded in intra mode which generates a large number of bits. The number of bits for the I-frame affects the qualities of the following frames of a GOP since they are encoded using the bits remaining among the bits allocated to the GOP. In addition, the first frame is used for the inter mode encoding of the following frames. Thus, the initial quantization parameter (QP) affects the following frames as well as the first frame. In this paper, an adaptive peak signal to noise ratio (PSNR)-based initial QP determination algorithm is presented. In the proposed algorithm, a novel linear model is established based on the observation of the relation between the initial QPs and PSNRs of frames. Using the linear model and PSNR results of the encoded GOPs, the proposed algorithm accurately estimates the optimal initial QP which maximizes the PSNR of the current GOP. It is shown by experimental results that the proposed algorithm predicts the optimal initial QP accurately and thus achieves better PSNR performance than that of the existing algorithm.

Isolated Word Recognition Using Segment Probability Model (분할확률 모델을 이용한 한국어 고립단어 인식)

  • 김진영;성경모
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.25 no.12
    • /
    • pp.1541-1547
    • /
    • 1988
  • In this paper, a new model for isolated word recognition called segment probability model is proposed. The proposed model is composed of two procedures of segmentation and modelling each segment. Therefore the spoken word is devided into arbitrary segments and observation probability in each segments is obtained using vector quantization. The proposed model is compared with pattern matching method and hidden Markov model by recognition experiment. The experimental results show that the proposed model is better than exsisting methods in terms of recognition rate and caculation amounts.

  • PDF

Designing Rich-Secure Network Covert Timing Channels Based on Nested Lattices

  • Liu, Weiwei;Liu, Guangjie;Ji, Xiaopeng;Zhai, Jiangtao;Dai, Yuewei
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.13 no.4
    • /
    • pp.1866-1883
    • /
    • 2019
  • As the youngest branch of information hiding, network covert timing channels conceal the existence of secret messages by manipulating the timing information of the overt traffic. The popular model-based framework for constructing covert timing channels always utilizes cumulative distribution function (CDF) of the inter-packet delays (IPDs) to modulate secret messages, whereas discards high-order statistics of the IPDs completely. The consequence is the vulnerability to high-order statistical tests, e.g., entropy test. In this study, a rich security model of covert timing channels is established based on IPD chains, which can be used to measure the distortion of multi-order timing statistics of a covert timing channel. To achieve rich security, we propose two types of covert timing channels based on nested lattices. The CDF of the IPDs is used to construct dot-lattice and interval-lattice for quantization, which can ensure the cell density of the lattice consistent with the joint distribution of the IPDs. Furthermore, compensative quantization and guard band strategy are employed to eliminate the regularity and enhance the robustness, respectively. Experimental results on real traffic show that the proposed schemes are rich-secure, and robust to channel interference, whereas some state-of-the-art covert timing channels cannot evade detection under the rich security model.

HMM-based Speech Recognition using DMS Model and Double Spectral Feature (DMS 모델과 이중 스펙트럼 특징을 이용한 HMM에 의한 음성 인식)

  • Ann Tae-Ock
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.7 no.4
    • /
    • pp.649-655
    • /
    • 2006
  • This paper proposes a HMM-based recognition method using DMSVQ(Dynamic Multi-Section Vector Quantization) codebook by DMS model and double spectral feature, as a method on the speech recognition of speaker-independent. LPC cepstrum parameter is used as a instantaneous spectral feature and LPC cepstrum's regression coefficient is used as a dynamic spectral feature These two spectral features are quantized as each VQ codebook. HMM using DMS model is modeled by receiving instantaneous spectral feature and dynamic spectral feature by input. Other experiments to compare with the results of recognition experiments using proposed method are implemented by the various conventional recognition methods under the equivalent environment of data and conditions. Through the experiment results, it is proved that the proposed method in this paper is superior to the conventional recognition methods.

  • PDF