• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.441-442
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• 2007

본 논문은 H.264 MB Layer 비트율 제어를 위한 적응적인 MAD 예측 방법을 제안한다. 첫째, 공간 인접 MB 들 간의 유사도를 기반으로 공간예측 MAD를 구하고 둘째, 프레임의 픽셀 평균값의 차이로 장면 전환을 검출한다. 셋째, 공간예측 MAD와 시간예측 MAD에 MB의 예측 움직임 벡터를 이용한 가중치를 주어 적응적으로 MAD를 예측한다. 실험 결과를 통해 제안한 MAD 예측 방법이 JM11.0의 방법보다 더욱 우수한 예측 성능을 보임을 살펴본다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.332-332
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• 2004

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.155-158
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• 2004

본 논문은 비트 플레인의 위치에 따라 블록별 적응적인 임계값를 이용하여 정보를 삽입하는 스테가노그라피 방법을 연구하였다. 다양한 이미지를 대상으로 고정 임계값을 적용하는 기존의 방법과 영상의 특징에 따라 비트 플레인별 임계값이 적응적으로 산출되는 제안한 방법에 대해서 최대용량을 측정하고, 같은 양의 정보를 삽입한 후 화질을 비교 분석하였다. 그 결과 기존의 방법 보다 용량면이나 화질면에서 나은 결과를 얻을 수 있었다.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.126-135
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• 2014

The Euclidean distance between error probability density functions (EDEP) has been used as a performance criterion for supervised adaptive signal processing in impulsive noise environments. One of the drawbacks of the EDEP algorithm is a heavy computational complexity due to the double summation operations at each iteration time. In this paper, a recursive method to reduce its computational burden in the estimation of the EDEP and its gradient is proposed. For the data block size N, the computational complexity for the estimation of the EDEP and its gradient can be reduced to O(N) by the proposed method, while the conventional estimation method has $O(N^2)$. In the performance test, the proposed EDEP and its gradient estimation yield the same estimation results in the steady state as the conventional block-processing method. The simulation results indicates that the proposed method can be effective in practical adaptive signal processing.

• Journal of Broadcast Engineering
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• v.14 no.5
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• pp.601-615
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• 2009

This paper proposes an efficient depth-map coding method for generating virtual-view images in 3D-Video. Virtual-view images can be generated by the view-interpolation based on the depth-map of the image. A conventional video coding method such as H.264 has been used. However, a conventional video coding method does not consider the image characteristics of the depth-map. Therefore, this paper proposes an adaptive depth-map coding method that can select between the H.264/AVC coding scheme and the proposed gray-coded bit plane-based coding scheme in a unit of block. This improves the coding efficiency of the depth-map data. Simulation results show that the proposed method, in comparison with the H.264/AVC coding scheme, improves the average BD-rate savings by 7.43% and the average BD-PSNR gains by 0.5dB. It also improves the subjective picture quality of synthesized virtual-view images using decoded depth-maps.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.391-396
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• 2013

In this paper, for HEVC decoding, an SAO hardware design with less processing time and reduced area is proposed. The proposed SAO hardware architecture introduces the design processing $8{\times}8$ CU to reduce the hardware area and uses internal registers to support $64{\times}64$ CU processing. Instead of previous top-down block partitioning, it uses bottom-up block partitioning to minimize the amount of calculation and processing time. As a result of synthesizing the proposed architecture with TSMC $0.18{\mu}m$ library, the gate area is 30.7k and the maximum frequency is 250MHz. The proposed SAO hardware architecture can process the decode of a macroblock in 64 cycles.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.9-18
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• 2016

This paper proposes a multi-view Wyner-Ziv Video coding scheme based on spatio-temporal adaptive estimation. The proposed algorithm is designed to search for a better estimated block with joint bi-directional motion estimation by introducing weights between temporal and spatial directions, and by classifying effectively the region of interest blocks, which is based on the edge detection and the synthesis, and by selecting the reference estimation block from the effective motion vector analysis. The proposed algorithm exploits the information of a single frame viewpoint and adjacent frame viewpoints, simultaneously and then generates adaptively side information in a variety of closure, and reflection regions to have a better performance. Through several simulations with multi-view video sequences, it is shown that the proposed algorithm performs visual quality improvement as well as bit-rate reduction, compared to the conventional methods.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.117-124
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• 2004

In this paper, we have been implemented the QPSK-based underwater transmission systems using DSP in order to transmit the underwater image data. We have adopted a BDPA (Block Data Parallel Architecture) to control multiple DSPs used in the transmitter and receiver in order to transmit the image data in real-time. We also have developed GUI software in order to drive and to debug the implemanted system in real-time. We have executed open sea tests in order to analyze the performance of the implemented system at East Sea near Kosung in Kangwon-Do. As a result of these experiments, it has been demonstrated that 10 kbps image data can be received without errors at 30m and 80m depth points, while the distance between the transmitter and the receiver is up to 20m.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.1 s.307
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• pp.75-84
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• 2006

With considering center-biased characteristic, NTSS(New Three-Step Search Algorithm) can improve the performance of TSS(Three-Step Search Algorithm) which is one of the most popular fast block matching algorithms(BMA) to search a motion vector in a video sequence. Although NTSS has generally better Quality than TSS for a small motion sequence, it is hard to say that NTSS can provide better quality than TSS for a large motion sequence. It even deteriorates the quality to increase a search window size using NTSS. In order to address this drawback, this paper aims to develop a new adaptive window size-based three step search scheme, called AWTSS, which can improve quality at various window sizes in both the small and the large motion video sequences. In this scheme, the search window size is dynamically changed to improve coding efficiency according to the characteristic of motion vectors. AWTSS can improve the video quality more than 0.5dB in case of large motion with keeping the same quality in case of small motion.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.79-86
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• 2003

A new quantization constraint set based on the theory of Projection onto Convex Set(POCS) is proposed to reduce blocking artifact appearing in block-coded images. POCS-based postprocessing for alleviating the blocking artifact consists of iterative projections onto smoothness constraint set and quantization constraint set, respectively. In general, the conventional quantization constraint set has the maximum size of range where original image data can be included, therefore over-blurring of restored image is unavoidable as iteration proceeds. The projection onto the proposed quantization constraint set can reduce blocking artifact as well as maintain the clearness of the decoded image, since it controls adaptively the size of quantization constraint set according to the DCT coefficients. Simulation results using the proposed quantization constraint set as a substitute for conventional quantization constraint set show that the blocking artifact of the decoded image can be reduced by the small number of iterations, and we know that the postprocessed image maintains the distinction of the decoded image.