• Broadcasting and Media Magazine
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• v.18 no.2
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• pp.92-99
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• 2013

기존의 Full HD보다 4배 이상 많은 화소를 한 화면에 담은 고품질의 디스플레이 장치가 출시되었고, 고해상도의 영상을 실어 보낼 수 있는 차세대 압축 기술인 HEVC(High Efficiency Video Coding)가 표준화 승인을 받았다. 또한 최근 고품질의 콘텐츠를 위해 영화에서는 프레임 레이트(frame rate) 변화가 일어나고 있으며, 디스플레이 환경 또한 하이 프레임 레이트(high frame rate, HFR)가 지원되고 있는 추세이다. 가정에서도 영화관 수준의 콘텐츠를 볼 수 있는 환경의 변화가 생겼음을 고려하였을 때, 해상도와 함께 프레임 레이트에 대한 연구가 필요하다. 따라서 본 기고에서는 UHD(Ultra High Definition)와 HFR의 의미, 그리고 고품질의 콘텐츠 제작 프로세스의 변화에 대해 알아본다.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.17-19
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• 2009

The voltage and frequency dependence of voltage holding ratio (VHR) in a homogeneously-aligned liquid-crystal (LC) cell is studied in this paper. The discharge curves with different scan frequencies are obtained and the saturation phenomenon of VHR is observed under specific amplitudes of driving voltage. Our results suggest a reasonable concept to improve the VHR in LC displays without increasing the frame rate.

• ETRI Journal
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• v.34 no.3
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• pp.470-473
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• 2012

In this letter, the constant driving power reduction ratio has been achieved for column drivers regardless of the input image by incorporating a new static power reduction scheme into the previous dynamic power reduction method. The measured power reduction ratio is around 50% for a 120 Hz liquid crystal display panel in such cases of still input video and fallback.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.259-260
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• 2007

In this paper, a frame rate up-conversion algorithm using the motion vector frequency of neighboring blocks to reduce the block artifacts caused by failure of conventional motion estimation based on block matching algorithm is proposed. Experimental results show good performance of the proposed scheme with significant reduction of the erroneous motion vectors and block artifacts.

• Journal of Communications and Networks
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• v.9 no.3
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• pp.213-218
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• 2007

Methods for symbol-by-symbol channel feedback and adaptation of symbol durations have been recently proposed. In this paper, we quantitatively analyze the gain in error-constrained data throughput due to such an extremely rapid adaptation of symbol durations to fast-time-varying channels. The results show that a symbol-by-symbol adaptation can achieve a throughput gain by orders of magnitude over a frame-by-frame adaptation.

• Proceedings of the Korea Contents Association Conference
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• 2019.05a
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• pp.93-94
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• 2019

초고속 프레임(Super High Frame Rate, HFR)은 관객에게 탁월한 이미지의 우월성을 전달한다. 그럼으로써 실제 눈으로 보지 못한 장면의 생생함을 통해 작품성에 기여하는 것이다. 이에 연구자는 영화에 나타난 초고속 프레임의 장면을 통해 시각적 효과를 분석하고자 한다. 특히 를 중심으로 초고속 프레임의 특징을 분석하여 향후의 작품제작에 기여하고자 한다.

• ETRI Journal
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• v.31 no.1
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• pp.21-30
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• 2009

In low bit-rate video transmission, the payload of a single packet can often contain a whole coded frame due to the high compression ratio in both spatial and temporal domains of most modern video coders. Thus, the loss of a single packet not only causes the loss of a whole frame, but also produces error propagation into subsequent frames. In this paper, we propose a novel whole frame error concealment algorithm which reconstructs the first of the subsequent frames instead of the current lost frame to suppress the effects of error propagation. In the proposed algorithm, we impose a constraint which uses side match distortion (SMD) and overlapped region difference (ORD) to estimate motion vectors between the target reconstructed frame and its reference frame. SMD measures the spatial smoothness connection between a block and its neighboring blocks. ORD is defined as the difference between the correlated pixels which are predicted from one reference pixel. Experimental results show that the proposed algorithm effectively suppresses error propagation and significantly outperforms other conventional techniques in terms of both peak signal-to-noise ratio performance and subjective visual quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1505-1514
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• 1997

In this paper, a temporally adaptive layered image sequence coding technique employing H.261 is proposed. In the proposed technique, the frame rate of the base layer is adjusted according to the temporal activity measure based on the rate-distortion function. The base layer is encoded using the H.261. Then, the full frame-rate error image is formed by comparing the original image and the interpolated version of the reconstructed base layer image. The enhancement layer is algo encoded using H.261 but with leaky prdiction to provide robust error resilience. The simulation results show that the proposed technique provides better performance than the twin-H.261 with leaky prediction in both the fixed-rate and variable-rate systems.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.9
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• pp.1325-1332
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• 2013

The first frame of a GOP, an I frame, is encoded in intra mode which generates a larger number of bits. In addition, the I frame is used for the inter mode encoding of the following frames. Thus the intial QP for the I frame affects the first frame as well as the following frames. In our previous work, we analyzed the number of bits for an I frame and showed that the ratio of the number of bits which maximizes the PSNR of a GOP maintains similar value regardless of GOP's. In this paper, we propose a R-Q model which can be used for the calculation of the initial QP given the amount of bits for an I frame. The proposed model is simple and adaptively modifies model parameters, so it can be applicable to the real-time application. It is shown by experimental results that the proposed model captures initial QP characteristics effectively and the proposed method for model parameters accurately estimates the real values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.1957-1964
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• 2010

In Video coding, the first frame 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 intial QP for the first frame of GOP affects the first frame as well as the following frames. Traditionally, the initial QP of a GOP is determined by the initial QP of the previous GOP and the average QP of the inter mode frames. In case of JM, the initial QP of a GOP is adjusted as the initial QP being less than the average QP of inter mode frames by two. However, this method is not suitable for the low bit rate video coding. In this paper, the linear relationship between the optimal QP and the ratio of the PSNR of the first frame and the average PSNR of the inter mode frames is first investigated and the linear model is proposed based on the results of the investigation. The proposed model calculate the optimal initial QP using the encoding results of the previous GOP. It is shown by experimental results that the new algorithm can predict the optimal initial QP more accurately and generate the PSNR performance better than that of the existing JM algorithm.