• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.253-260
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• 2004

This paper proposes a novel algorithm for hybrid lossless audio coding, which employs an integer wavelet transform and a linear prediction model. The proposed algorithm divides the input signal into flames of a proper length, decorrelates the framed data using the integer wavelet transform and linear prediction and finally entropy-codes the frame data. In particular, the adaptive Golomb-Rice coding method used for the entropy coding selects an optimal option which gives the best compression efficiency. Since the proposed algorithm uses integer operations, it significantly improves the computation speed in comparison with an algorithm using real or floating-point operations. When the coding algorithm is implemented in hardware, the system complexity as well as the power consumption is remarkably reduced. Finally, because each frame is independently coded and is byte-aligned with respect to the frame header, it is convenient to move, search, and edit the coded, compressed data.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.886-888
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• 2004

본 논문에서는 현재 프레임 블록의 인접 블록으로부터 예측된 움직임 정보를 구하여, 이를 탐색 원점으로 하여 한 방향으로 진행하는 수정된 다이아몬드 지역 레이더 패턴으로 블록정합을 수행하는 수정된 다이아몬드 지역탐색 알고리즘을 제안한다. 실험 결과 제안된 방식은 기존의 방식들에 비해 PSNR 간에 있어서 평균적으로 0.02~0.37(㏈) 개선되고 속도면에서 우수한 결과를 나타내었다. 또한 기존의 다이아몬드 지역탐색 알고리즘보다 탐색 속도면에서 14~24%의 성능향상을 보이면서 화질면에서는 거의 근접하게 나타났다. 제안된 방식은 정량적인 결과뿐만 아니라 부호화후 복호화한 영상의 화질에 있어서도 다른 고속 탐색 알고리즘보다 월등히 우수한 화질을 제공한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.17-25
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• 2013

In this paper, a coding algorithm is proposed for multi-user multi-input multi-output (MU-MIMO) systems to improve the reception performance in fading conditions without reducing the bandwidth efficiency. The space division multiple access (SDMA) scheme that is one of the commonly used for MU-MIMO systems is vulnerable to the fading. The space time block code (STBC) scheme that is used to overcome the fading has a disadvantage of reduced throughput. The proposed MU-MIMO system first encodes transmitted symbols by linear dispersion code (LDC) which is less vulnerable to the fading and increases the throughput in proportional to the number of transmit antennas. Then, the LDC coded symbols are pre-coded by the result of singular value decomposition (SVD) of the estimated channel gain. We evaluate the performance of the proposed scheme compared with the conventional algorithms by computer simulations.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.140-146
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• 1989

An efficient quantization and encoding of BTC (Block Truncation Coding) parameters {($Y_{\alpha},\;Y_{\beta}),\;P_{{\beta}/{\beta}}$} are investigated, In our algorithm 4${\times}$4 blocks are classified into flat or edge block. While edge block is represented by two approximation level $Y_{\alpha},\;Y_{\beta}$ with label plane $P_{{\beta}/{\beta}}$, flat block is represented by single approximation level Y. The approximation levels Y, $Y_{\alpha}$ and $Y_{\beta}$ are encoded by predictive quatization specially designed, and the label plane $P_{{\beta}/{\beta}}$ is tried to be encoded using stored 32 reference plantes. The performance of the proposed scheme has appeared comparable to much more complex transform coding in terms of SNR, although it requires more study on the representation of small slope in background.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.1055-1061
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• 2008

H.264 is the prominent video coding standard in various applications such as real-time streaming and digital multimedia broadcasting, since it provides enhanced compression performance, error resilience tools, and network adaptation. Compression efficiency of H.264 has been improved, however, it requires more computing and memory access than traditional methods. In this paper we proposed adaptive intra fast algorithm for real-time video surveillance system reducing the encoding complexity of H264/A VC. For this aim, temporal interrelationship between macroblock in the previous and the current frame is used to decide the encoding mode of macroblock fast. As a result, though video quality was deteriorated a little, less than 0.04dB, and bit rate was somewhat increased in suggested method, however, proposed method improved encoding time significantly and, in particular, encoding time of an image with little changes of neighboring background such as surveillance video was more shortened than traditional methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.72-82
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• 2004

This paper proposes more robust error concealment techniques (ECTs) for MPEG-2 intra coded frame. MPEG-2 source coding algorithm is very sensitive to transmission errors due to the use of variable-length coding. The transmission errors are corrected by error correction scheme, however, they cannot be revised properly. Error concealment (EC) is used to conceal the errors which are not corrected by error correction and to provide minimum visual distortion at the decoder. If errors are generated in intra coded frame, that is the starting frame of GOP, they are propagated to other inter coded frames due to the nature of motion compensated prediction coding. Such propagation of error may cause severe visual distortion. The proposed algorithm in this paper utilizes the spatio-temporal information of neighboring inter coded frames to conceal the successive slices errors occurred in I-frame. The proposed method also overcomes the problems that previous ECTs reside. The proposed algorithm generates consistent performance even in network where the violent transmission errors frequently occur. Algorithm is performed in MPEG-2 video codec and we can confirm that the proposed algorithm provides less visible distortion and higher PSNR than other approaches through simulations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1513-1526
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• 2009

The SVC (Scalable Video Coding) scheme can be effectively used for reducing the redundancy and for improving the coding efficiency but, it requires very high computational complexities. In order to accelerate the successful standardization and commercialization of the Advanced Terrestrial-DMB service, it is necessary to overcome this problem. For this aim, in this paper, we propose an efficient aggregated encoder control algorithm, which shows better performances than the conventional control scheme. Computer simulation result shows that the proposed scheme performs about up to 0.3dB better than those of the conventional scheme. Additionally, based on this control scheme, we propose a fast mode decision method by constraining the redundant coding modes based on the statistical properties of the quantization parameter in the spatial scalable encoder. Through computer simulations, it is shown that the proposed control schemes reduce the heavy computational burden up to 12% compared to the conventional scheme, while keeping the objective visual qualify very high.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1355-1363
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• 2017

Recently, distributed compressed video sensing (DCVS) has been actively studied in order to achieve a low complexity video encoder by integrating both compressed sensing and distributed video coding characteristics. Conventionally, a motion compensated block compressed sensing with smoothed projected Landweber (MC-BCS-SPL) has been considered as an effective scheme of DCVS with all compressed sensing frames pursuing the simplest sampling. In this scheme, video frames are separately classified into key frames and WZ frames. However, when reconstructing WZ frame with conventional MC-BCS-SPL scheme at the decoder side, the visual qualities are poor for temporally active video sequences. In this paper, to overcome the drawbacks of the conventional scheme, an enhanced MC-BCS-SPL algorithm is proposed, which corrects the initial image with reference to the key frame using a high correlation between adjacent key frames. The proposed scheme is analyzed with respect to GOP (Group of Pictures) structuring method. Experimental results show that the proposed method performs better than conventional MC-BCS-SPL in rate-distortion.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.6 s.312
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• pp.97-104
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• 2006

The state-of-the-art H.264/AVC standard was designed for the lossy video coding so that it could not yield the best performance for lossless video coding. In this paper, we propose two efficient intra lossless coding methods by embedding a pixel-wise prediction into the H.264/AVC. One is based on the pixel-wise prediction for the residual signal of the H.264/AVC intra Prediction and the other suggests a newly additional intra prediction mode for the conventional intra prediction. We found that the proposed lossless coding algorithms could achieve approximately $12%{\sim}25%$ more bit saving compared to the H.264/AVC FRExt high profile for several test sequences in terms of a compression ratio.

• Journal of Korea Multimedia Society
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• v.14 no.7
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• pp.917-923
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• 2011

In this paper, a new prediction based embedded compression (EC) codec algorithm for the JPEG2000 encoder system is proposed to reduce excessive memory requirements. The EC technique can reduce the 50 % memory requirement for intermediate low-frequency coefficients during multiple discrete wavelet transform (DWT) stages compared with direct implementation of the DWT engine of this paper. The LOCO-I predictor and MAP are widely used in many lossless picture compression codec. The proposed EC algorithm use these predictor which are very simple but surprisingly effective. The predictive EC scheme adopts a forward adaptive quantization and fixed length coding to encoding the prediction error. Simulation results show that our LOCO-I and MAP based EC codecs present only PSNR degradation of 0.48 and 0.26 dB in average, respectively. The proposed algorithm improves the average PSNR by 1.39 dB compared to the previous work in [9].