• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.367-372
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• 1995

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.6
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• pp.100-110
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• 2007

When compressed video data is transmitted over error-prone network such as wireless channel, data is likely to be lost, so the quality of reconstructed picture is severely decreased. It is specially so in case that important information such as motion vector or macroblock mode is lost. H.264/AVC standard includes DP as error resilient technique for protecting important information from error in which data is labeled according to its relative importance. But DP technique requires a network that supports different reliabilities of transmitted data. In general, the benefits of UEP is sought by sending multiple times of same packets corresponding to important information. In this paper, we propose MDC technique based on data partitioning technique. The proposed method encodes motion vector of H.264/AVC standard into multiple parts using MDC and transmits each part as independent packet. Even if partial packet is lost, the proposed scheme can decode the compressed bitstream by using estimated motion vector with partial packets correctly transmitted, so that achieving improved performance of error concealment with minimal effect of channel error. Also in decoding process, the proposed multiple description matching increases the accuracy of estimated lost motion vector and quality of reconstructed video.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.116-117
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• 2019

새로운 비디오 부호화 표준으로 JVET 에서 표준화 중인 VVC(Versatile Video Coding)에서는 더욱 유연한 화면간 예측을 위해 TPM(Triangular Partitioning Mode)을 채택하여 적용하고 있다. 하지만, TPM을 위한 추가적인 움직임 탐색 및 움직임 정보 저장은 VVC 부/복호화기의 복잡도를 증가시킨다. 본 논문에서는 TPM의 복잡도를 줄이기 위한 간소화 기법을 제안한다. 제안기법은 분할된 두개의 삼각 블록에 대한 움직임 정보 조합의 수를 줄여 움직임 탐색의 수를 줄이고 전송되는 데이터의 오버헤드도 함께 줄이는 TPM 간소화 기법이다. 실험결과, 제안기법은 RA(Random Access)와 LDB(Low-Delay B) 부호화 모드에서 미미한 성능 감소가 있었지만 4~6%의 두드러진 부호화 수행 시간 감소를 확인할 수 있었다.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.297-305
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• 2003

In this paper, we propose a wavelet based fast motion estimation algorithm for video sequence encoding with very low bit-rate. By using one of properties oi wavelet transform, multi-resolution analysis(MRA) property and spatial Interpolation of an image, we are able to reduce both prediction error and computational complexity at the same time. Especially, by defining a significant block(SB) based on the differential information of wavelet coefficients between successive frames, the proposed algorithm makes up a defect of multi-resolution motion estimation(MRME) algorithm of increasing the number of motion vectors. As experimental results. we can reduce the computational load up to 70% but also improve PSNR up to about 0.1 ∼ 1.2 dB comparing with the MRME algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.126-133
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• 2003

This paper is related to a morphological segmentation method for extracting the moving object in video sequence using global motion compensation and two-dimensional spatio-temporal entropic thresholding. First, global motion compensation is performed with camera panning vector estimated in the hierarchical pyramid structure constructed by wavelet transform. Secondly, the regions with high possibility to include the moving object between two consecutive frames are extracted block by block from the global motion compensated image using two-dimensional spatio-temporal entropic thresholding. Afterwards, the LUT classifying each block into one among changed block, uncertain block, stationary block according to the results classified by two-dimensional spatio-temporal entropic thresholding is made out. Next, by adaptively selecting the initial search layer and the search range referring to the LUT, the proposed HBMA can effectively carry out fast motion estimation and extract object-included region in the hierarchical pyramid structure. Finally, after we define the thresholded gradient image in the object-included region, and apply the morphological segmentation method to the object-included region pixel by pixel and extract the moving object included in video sequence. As shown in the results of computer simulation, the proposed method provides relatively good segmentation results for moving object and specially comes up with reasonable segmentation results in the edge areas with lower contrast.

• The Journal of Korean society of community based occupational therapy
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• v.3 no.2
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• pp.25-32
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• 2013

Objective : The purpose of this study was to investigate the effect of the ankle movement and the balance when the elderly conducted self-exercise with ankle movement control device through visual feedback. Method : This case-study included pre-test and post-test. The elderly women aged 80 did self-exercise for 20 minutes both morning and afternoon every day. The pre-test and post-test was conducted tracking test for evaluating ankle control movement and running time measurement of standing on one foot and Timed up-And-Go test for balance. Result : The subject improved the ankle control movement on tracking test and improved the balance in running time measurement of standing on one foot. But, Timed up-And-Go test was no change. Conclusion : The self-exercise with device of ankle movement control through visual feedback improved the ankle control movement and the balance for elderly.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.147-150
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• 2000

본 논문은 무인감시 시스템의 특성상 조명 상태의 변화나 카메라의 흔들림과 같은 환경의 변화에 적응할 수 있도록 연속된 세 프레임간의 차영상를 이용하는 방법을 적용하여 움직임 정보를 추출하고, 영역의 분할 및 특징점 추출을 수행한 후에, 인공 신경회로망 기법을 적용하여 이동표적을 추적한다. 추적시에는 추출된 각각의 표적간의 데이터 연결을 움직임 정보의 특징점들을 이용, 레이블링하여 각각의 표적을 연결시켜 추적의 성능을 높였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.85-91
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• 2015

This paper presents a novel frame rate up-conversion (FRUC) algorithm. Existing algorithms, in general, employ rectangular blocks for motion estimation and arbitrary shape of an actual object region cannot be precisely represented. On the other hand, the proposed wedge-shaped block partitioning algorithm partitions a rectangular block into two wedge-shaped blocks using the texture information, which makes better approximation for an actual object region. The wedge-shaped block partitioning algorithm as well as the adaptive motion vector prediction algorithm is used to reliably estimate the actual motion. Experimental results show that the proposed FRUC algorithm is superior to existing algorithms up to 1.988dB in PSNR and 0.0167 in SSIM comparisons.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11a
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• pp.290-293
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• 2003

다중 물체 추적은 움직이는 물체를 추출하고 검출된 정보와 물체 정보를 이용하여 움직임 궤도률 추적하는 것이다. 따라서 정확한 움직임 추적이 수행되려면 효율적인 물체의 추출이 선행 되어 져야 한다. 일반적으로 영상 분할 알고리즘은 다양한 증류의 영상에 대한 물체의 수학적 모델이 찌대로 설정되어 있지 않기 때문에 물체를 정확하게 분리해 내기 어렵다. 그러나 물체의 추출에 주로 처리 속도가 빠른 배경영상을 이용한 차(difference) 영상 기법과 반 자동 영상분할인 Snake Model이 갖는 Active Contour 알고리즘과 같이 물체 추출 과정에서 물체의 정의니 semantic 정보를 부여 한다면 개선된 영상 분할의 결과를 얻을 수 있다. 따라서 차 영상 기법과 semantic 정보를 가진 영상분할 알고리즘은 동영상에서 움직임 물체의 VOP(Video Object Plane)를 생성하는 매우 현실적인 방법이다. 본 논문에서는 영상의 상위 레벨Semantic 정보를 이용하기 위해 변형 Snake Model를 이용한 영상분할 방법을 이용하여 영상을 추출한다. 추출된 물체는 윤곽선(곡선) 정보와 함께 에지 성분의 기울기에서 얻은 특징 점을 이용하여 물체를 추적해 나간다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.553-555
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• 2001

Markov Random Fields(MRF) 모델은 영상 분할 및 복원 등에 주로 사용되는 확률적 영상모델이다. 본 논문에서는 MRF 모델을 3차원으로 확장하여 분할을 위한 선 필드 모델(Line Field Model)과 움직임 검출을 위한 움직임 필드 모델(Motion Field Model)을 도입하여 동영상 내에서 움직이는 물체의 형상과 움직임을 추정한다. 제안된 방법을 이용하여 한국어 수화 동작에서 손의 형상과 이동방향을 검출하였다. 그 결과 optical flow를 사용하는 방법에 비해서 이동 방향이 왜곡되는 것을 방지하여 보다 정확한 이동 방향을 검출할 수 있었다. 또한 영상 추출의 경우에 있어서도 형상의 윤곽면과 내부가 하나의 라벨(label)로 묶이기 때문에 보다 깨끗한 영상을 추출할 수 있었다.