• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.77-79
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• 2013

본 논문에서는 광원 정보를 사용하여 다양한 재생환경에서 효과적인 홀로그래픽 비디오 서비스를 제공하기 위한 방법을 제안한다. 제안하는 기법에서 부호화 과정에서는 가우시안 블러를 적용한 영상의 개수를 조절, 분리 하고 다운 샘플링 한 하나의 영상 압축을 한 뒤 전송한다. 이 영상을 다운 샘플링, 업 샘플링, 보간법, 양방향 필터 (Bi-lateral filter) 등의 기법을 이용하여 획득한 영상과 나머지 영상을 다운 샘플링과 업 샘플링 하여 더한 영상의 차를 압축하여 수신측으로 전송한다. 복호화 과정에서는 압축된 광원 정보를 복원한 후 기본계층 정보를 가진 영상을 업 샘플링과 보간법, 양방향 필터 (Bi-lateral filter) 등의 기법을 적용하고 수신자의 환경과 고려에 따라 차영상을 더 한 후 CGH를 통해 홀로그램을 획득하였다. 실험을 통해 제안하는 기법이 기존의 방법들 보다 우수한 홀로그램을 복원 할 수 있다는 것을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.743-750
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• 2000

In this paper, low-power block filtering architecture for digital If down sampler and up sampler is proposed. Software radio technology requires low power and cost effective digital If down and up sampler. Digital If down sampler and up sampler are accompanied with decimation filter and interpolation filter, respectively. In the proposed down sampler architecture, it is shown that the parallel and low-speed processing architecture can be produced by cancellation of inherent up sampler of block filter and down sampler. Proposed up sampler also utilizes cancellation of up sampler and inherent down sampler of block filtering structure. The proposed architecture is compared with the conventional polyphase architecture.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.29-30
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• 2015

본 논문에서는 음악 시디에 사용되는 44.1khz의 포맷으로 녹음된 주파수와, 고품질 녹음시 선택하는 포맷인 96khz로 녹음한 주파수를 다시 44.1khz로 다운 샘플링한 주파수를 비교 분석한다. 다양한 주파수를 다운 샘플링 한 후 변화된 주파수의 평균을 분석하여 이의 특성을 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.631-633
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• 2022

인체 선형 모델 (이하 SMPL 모델)은 3 차원 사람 모델로, 3 차원 컴퓨터 그래픽 기술이 발전함에 따라 활용 범위가 확대될 수 있다. 다운샘플링 (Down-sampling)으로 여러 해상도의 SMPL 모델이 사용가능 하다면, 3 차원 컴퓨터 그래픽 기술 발전에 도움이 될 것이다. 3 차원 모델의 다운샘플링을 위한 많은 메쉬 단순화 (Mesh simplification) 기법이 존재한다. 하지만 기존의 기법만을 사용하면 다운 샘플링 한 모델의 자세 (Pose)를 변경했을 때 기대한 것과 다른 결과물이 만들어지는 문제가 발생한다. 본 논문에서는 가장 가까운 정점으로 SMPL 모델의 관절 회귀자 (Joint regressor) 값을 넘겨주어 문제를 해결하는 다운샘플링 (Down-sampling) 방법을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37A no.11
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• pp.918-926
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• 2012

In 3D video transmission, a depth map being used for depth image based rendering (DIBR) is generally compressed by reducing resolution for coding efficiency. Errors in resolution reduction are recovered by an appropriate up-sampling method after decoding. However, most previous works only focus on up-sampling techniques to reduce errors. In this paper, we propose a novel down-sampling technique of depth map that applies different down-sampling rates on moving objects and background in order to enhance human perceptual quality. Experimental results demonstrate that the proposed scheme provides both higher visual quality and peak signal-to-noise ratio (PSNR). Also, our method is compatible with other up-sampling techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.46-49
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• 2017

In this letter, we investigate the impact of image downsampling on the performance of background subtraction in Full-HD soccer videos. To this end, we evaluated the performance of background subtraction in terms of both accuracy and computational time. Furthermore, for the sake of completeness, we used two different background subtraction methods under the same experimental setup. For the quantitative comparison, we employed the F-measure and FPS(frames per second). We believe that this study serves as a practically useful benchmark for researchers and practitioners in developing a fast background subtraction algorithm adopted for building real-time intelligent soccer video analysis systems.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.37 no.5
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• pp.115-123
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• 2000

In this paper, a block FIR(Finite Impulse Response) filtering architecture is proposed for IF digital down converter. Digital down converter consists of digital mixers. decimation filters and down samplers. In this proposed structure, it is shown that a efficient parallel decimation filter architecture can be produced by cancellation of inherent up sampling of the block filter and following down sampler Furthermore. it is shown that computational complexity of the proposed architecture is reduced by exploiting the block FIR structure and zero values of the digital mixers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.465-469
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• 2017

In this paper we propose a human body tracking method for application of smartphones. The conventional human body tracking method is divided into a sensor-based method and a vision-based method. The sensor-based methods have a weakness in that tracking accuracy is low due to cumulative error of position information. The vision-based method has no cumulative error, but it requires reduction of the computational complexity for application of smartphone. In this paper we use the improved HOG algorithm as a human body tracking method for application of smartphone. The improved HOG algorithm is implemented through downsampling and frame sampling. Gaussian pyramid is applied for downsampling, and uniform sampling is applied for frame sampling. We measured the proposed algorithm on two devices, four resolutions, and four frame sampling intervals. We derive the best detection rate among downsampling and frame sampling parameters that can be applied in realtime.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.78-79
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• 2021

본 논문에서는 시간 영역 오토인코더의 성능 개선을 위한 다중 대역 손실 함수를 제안한다. 기존의 시간 영역 오토인코더를 사용하는 압축 및 복원 모델은 저 대역 손실에 치중되어 고 대역 신호를 생성하지 못하고 다운 샘플링된 신호를 결과로 출력하는 문제점을 가진다. 이를 해결하기 위해 대역별로 손실을 분리하여 가중치를 조절할 수 있는 다중 대역 손실 함수를 제안한다. 제안하는 손실 함수가 적용된 오토인코더에 음성 신호를 입력하여 학습을 진행한 결과, 다운 샘플링이 발생하지 않으며 고 대역 신호가 복원되는 것을 스펙트로그램을 통해 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.117-124
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• 2004

Various multimedia systems have been developed and their application areas widely proliferate. Thus, the interoperability is getting important among various networks and devices. The video transcoding is a technology to solve this interoperability problem among various coding standards. Transcoding can be defined as the conversion of one compressed coded data to another. In this paper, MPEG-2 to MPEG-4 transcoder in the spatial domain is compared with that in the DCT domain. The transcoder is very useful when a video sequence that is originally encoded for digital TV, DVD or satellite broadcasting is served in mobile environment. In order to compare two transcoders, all modules except motion compensation and down sampling are implemented identically. In addition, both transcoders do not search for motion vector. Instead, the decoded information is reused to the encoder. The experimental results show that the transcoder in the spatial domain is usually better than that in the DCT domain with respect to PSNR (Peak Signal-to-Noise Ratio), bitrate and execution time.