• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.250-253
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• 2009

This paper presents NR (No Reference) Quality assessment method for IPTV or mobile IPTV. Because No Reference quality assessment method does not access the original signal so it is suitable for the real-time streaming service. Our proposed method use decoding parameters, such as quantization parameter, motion vector, and packet loss as a major network parameter. To evaluate performance of the proposed algorithm, we carried out subjective test of video quality with the ITU-T P.910 ACR (Absolute Category Rating) method and obtained the mean opinion score (MOS) value for QVGA 180 video sequence coded by H.264/AVC encoder. Experimental results show the proposed quality metric has a high correlation (84%) to subjective quality.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.23-27
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• 2009

A scalable video coding (SVC) extension to the H.264/AVC standard has been developed by the Joint Video Team (JVT). SVC provides spatial, temporal and quality scalability with high coding efficiency and low complexity. SVC is now developing the extension of the first version including color format scalability. The paper proposes to remove some luminance related header and luminance coefficients when an enhancement layer adds only additional color information to its lower layer. Experimental results shows 0.6 dB PSNR gain on average in coding efficiency compared with an approach using the existing SVC standard.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.263-266
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• 2009

When video packets are transmitted over error-prone networks, the leaky prediction can be used to mitigate the effect of error propagation. The leaky factor provides trade-off between coding efficiency and error resilience in the leaky prediction. In this paper, we propose an improved leaky prediction method where the leaky factor is adaptively determined for each frame by minimizing the estimated end-to-end distortion at the encoder. Experimental results show that the proposed method with the adaptive leaky factor shows the better performance of the error robustness as compared with the conventional method.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10a
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• pp.751-754
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• 2000

In this paper, we propose an efficient method to detect abrupt shot changes in compressed MPEG video data by using reference ratios among video frames. The reference ratios among video frames imply the degree of similarities among adjacent frames by prediction coded type of each frames. A shot change is detected if the similarity degrees of a frame and its adjacent frames are low. This paper proposes an efficient shot change detection algorithm by using Fuzzy c-means(FCM) clustering algorithm. The FCM clustering uses the shot change probabilities evaluated in the mask matching of reference ratios and difference measure values based on frame reference ratios.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.151-154
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• 2005

본 논문에서는 스케일러블 멀티미디어 콘텐츠에 대한 조건적 접근제어가 가능한 암호화 방법을 제안한다. 현재 표준화가 진행중인 스케일러블 비디오 코딩방법인 JSVM(Joint Scalable Video Model)은 부호화한 동영상에 대해 공간, 시간, 품질의 스케일러빌리티(Scalability)를 지원하는데, 각 스케일러 빌리티를 고려한 조건적인 접근제어기술은 스케일러빌리티에 따라 사용자를 제한해야 하는 경우를 위해 필수적인 기술이다. 제안하는 방법은 공간, 시간, 품질의 세가지 스케일러빌리티를 지원하도록 부호화(Encoding)후 구성되는 NAL(Network Abstract Layer)을 지원하는 스케일러빌리티에 따라 구분하고, 구분된 NAL 의 종류에 따라 암호화 key 를 다르게 제공하는 방법을 통해 사용자의 접근제어 수준에 맞게 암호화 key 를 조합하는 방법을 적용하였다. 실험 결과 제안한 방법은 JSVM 에서 공간, 시간, 품질의 스케일러빌리티가 보장되고, 이때 생성되는 Key 의 조합으로 조건적 접근제어(Conditional access control)가 가능함을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06b
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• pp.61-66
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• 1996

In this paper, an efficient contour coding algorithm incorporating polygonal approximation and discrete sine transform is introduced. Contour information is inevitable in content based coding, and polygonal approximation method is widely used to compress the contour information. However polygonal approximation method is not suitable when fine contour is needed. We show that the error signal of polygonal approximation can be efficiently represented using DST, that is, the contour information can be represented accurately with polygons and DST coefficients. With this contour coding scheme, the required bits to represent a contour can be reduced by about 40-50% with virtually no degradation compared to the existing chain coding method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06a
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• pp.3-8
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• 1998

The conversion of monoscopic video to 3D stereoscopic video has been studied by some pioneering researchers. In spite of the commercial of potential of the technology, two problems have bothered the progress of this research area: vertical motion parallax and high computational complexity. The former causes the low 3D perception, while the hardware complexity is required by the latter. The previous research has dealt with NTSC video, thur requiring complex processing steps, one of which is motion estimation. This paper proposes 3D stereoscopic conversion method of MPGE encoded data. Our proposed method has the advantage that motion estimation can be avoided by processing MPEG compressed data for the extraction of motion data as well as that camera and object motion in random in random directions can be handled.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.508-511
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• 2007

Car navigation system is one of the most important applications in telematics. A newest trend of car navigation system is using real video captured by camera equipped on the vehicle, because video can overcome the semantic gap between map and real world. In this paper, we suggest a visual car navigation system that visually represents navigation information or route guidance. It can improve drivers' understanding about real world by capturing real-time video and displaying navigation information overlaid on it. Main services of the visual car navigation system are graphical turn guidance and lane change guidance. We suggest the system architecture that implements the services by integrating conventional route finding and guidance, computer vision functions, and augmented reality display functions. What we designed as a core part of the system is visual navigation controller, which controls other modules and dynamically determines visual representation methods of navigation information according to a determination rule based on current location and driving circumstances. We briefly show the implementation of system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.40-41
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• 2012

양안식 3D 영상 시청 안정성에 대해 제기되고 있는 지속적인 이슈는 3D 영상 시장 활성화를 위해 반드시 선결 되어야 하는 과제이다. 최근, 이를 위해 양안식 3D 영상이 유발하는 시각적 불편함을 측정하고 이를 예측하는 연구가 활발히 진행되고 있다. 본 논문에서는 양안식 3D 영상에서 시각적 불편함을 야기하는 문제 영역의 양안 시차 변화에 따른 주관적 시각적 불편함을 측정한다. 이를 통하여 양안식 3D 영상에서 시각적 불편함을 주는 문제 영역의 영상 특성이 시청자가 인지하는 시각 피로에 지배적인 영향을 미칠 수 있음을 실험적으로 증명한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.177-182
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• 1998

In this paper, we propose a lossless motion video coding method using motion compensation. For realtime coding and transmission, we developed a lossless video codec based on the proposed method. It was confirmed the codec functions normally in an experiment involving coding and transmitting through an actual ATM network. Furthermore, we proposed a lossless coding method with bit-plane expansion under a constant bitrate. Two approaches, a closed bit-plane approach and a merged bit-plane approach, are considered and characteristics of their compression efficiency are estimated. Simulation results show that the proposed method is suitable for lossless video coding with bitrate control.