• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.193-195
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• 2006

애드 혹 네트워크에 있어서 브로드캐스팅을 실현 시 전달 메시지가 과중하게 중복 발생하는 것을 줄이기 위해 메시지를 수신하고 전달하는 역할을 맡는 전달 노드들을 in-fly 형태로 지정하도록 하는 기법 중 가장 실용적인 것으로는 PDP(Partial Dominant Pruning) 기법을 들 수 있다. 본 논문에서는 PDP를 확장 하여 방향성 안테나를 이용하는 애드 혹 네트워크에 있어서 전달 노드들의 수는 물론, 이때 수반되는 안테나 요소 수를 동시에 줄이도록 하는 확장된 DPDP (Directional PDP) 기법을 제안한다. 시뮬레이션을 통해 사용 안테나 요소 수(K)가 증가함에 따라 선정되는 전달 노드의 수는 전 방향 안테나를 사용하는 경우에 비해 다소 증가하지만 평균 전달 비용과 노드별 메시지 중복 수신 수에서는 PDP 기법에 비해 우수함을 확인하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2014.06a
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• pp.79-80
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• 2014

본 논문에서는 다방향 패턴을 이용한 구조광(structured light)방식의 3차원 스캔 기법을 적용하여 3차원 스캐너의 3차원 형상 취득의 정밀도를 높이는 방법을 제안한다. 기존의 단방향 패턴을 이용한 3차원 구조광 방식의 스캔 기법으로 3차원 형상을 취득하는 경우, 스캔 대상 표면의 법선벡터가 패턴의 방향과 수평 할수록 부정확한 형상이 복원된다. 본 논문에서는 스캔 대상의 경사면에 따른 법선 벡터(normal vector) 검출 및 검출된 벡터를 통한 최적의 패턴 방향 선출(quantization), 그리고 각 화소의 최적의 패턴방향을 이용한 선별적인 구조광 방식의 3차원 스캔 기법을 통하여 3차원 형상 취득의 정확성을 높이는 기법을 제안한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.32-35
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• 2010

This paper presents an efficient monitoring method of a network protocol for a downloadable conditional access system (DCAS) that can securely transmit conditional access software via a bi-directional communication channel. In order to guarantee a secure channel based on mutual authentication between a DCAS head end server and set-top boxes, DCAS messages are encrypted and digitally signed. Owing to applied cryptographic algorithms, it is impossible to get information from messages directly without additional processing. Through categorizing DCAS messages into several groups, the proposed monitoring method can efficiently parse and trace DCAS messages in real-time. In order to verify the stability and effectiveness of the proposed monitoring method, we implement a DCAS monitoring system capable of capturing and parsing all DCAS messages. The experimental results show that the proposed monitoring method is well designed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.360-363
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• 2009

Variation of viewing position of the observer is one of factors of image distortion in the stereoscopic display. A rotation movement of the observer makes the stereoscopic image distortion and that is caused by different horizontal position of each eye of the observer. It is different from horizontal and depth directional movement of the observer. In this paper, we showed the numerical simulation result about the distortion analysis and the correction of the stereoscopic image in rotation movement of the observer.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.200-203
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• 2011

In order to convert interlaced video into progressive scanning format, this paper proposed a high performance de-interlacing algorithm based on region adaptive interpolation filter design. Specifically, usage of the 6-tap filter is only for the most complex region, but for the smooth and regular edge region, much more correlated filter such as 2-tap or 4-tap filter should be used instead. According to the experimental results, the proposed algorithm has achieved noticeably good performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.15-17
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• 2018

본 논문에서는 시장규모가 점진적으로 커지고 있는 VR의 콘텐츠 제작에 있어서 전방위 영상 생성을 위해 촬영한 영상들을 스티칭하는 데 소요되는 연산량을 감소시키는 방법을 제안한다. 제안하는 방법은 널리 사용되는 SIFT의 알고리즘에서 가장 많은 연산을 차지하는 가우시안 피라미드 생성 부분을 파라미터를 조절하여 감소시키고, 이를 통해 얻은 점들을 스티칭하는데 사용하여 영상을 합성하는 방법이다. 영상에 대한 평가는 변환에 의한 점들의 평균오차를 계산하여 유효성을 판단한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.272-275
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• 2020

Light Field (LF) cameras capture both spatial and directional information of light rays. Current LF cameras have a problem of a low spatial resolution. There have been lots of existing works carried out to improve the resolution of LF images. In this paper, those existing works will be divided into two categories: hardware-based approaches and software-based approaches, and we will look into and compare several experiment results in order for LF spatial resolution enhancement. Finally, the direction for the future spatial resolution enhancement will be suggested.

• Journal of Broadcast Engineering
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• v.9 no.3
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• pp.196-206
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• 2004

This paper presents an efficient joint disparity-motion estimation algorithm for stereo sequence CODEC. Disparity vectors are estimated by the left and right motion vectors and previous disparity vectors for every frame. In order to obtain more accurate disparity vectors. we include a spatial prediction Process after the feint estimation. From joint estimation and spatial prediction, we can obtain accurate disparity vectors and then Increase coding efficiency. Finally, we proposed the backward quadtree decomposition. which helps the encoder to have a more detailed disparity vector map without transmitting additional coding bits for quadtree information. We confirmed superior performance of the proposed method through computer simulation.

• Journal of Broadcast Engineering
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• v.4 no.1
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• pp.59-67
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• 1999

In this paper, we study two important topics in stereoscopic image communication system. One is a disparity estimation (DE) method to obtain the depth information of a scene at the transmitter and the other is an intermediate view reconstruction(IVR) method at the receiver. We propose a new DE method using an edge-preserving directional regularization technique. The proposed DE method smooths disparity vectors in smooth regions and preserves edges without over-smoothing problem. It provides better reconstructed stereoscopic images and improved coding efficiency than the existing regularization techniques. In addition. we propose a new IVR method using interpolation and extrapolation techniques. The proposed IVR method preserves edge regions as well as occlusion regions well. Thus. it gives better intermediate views than the existing IVR methods.

• Journal of Broadcast Engineering
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• v.16 no.1
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• pp.44-53
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• 2011

In this paper, we propose a 3D conversion algorithm of 2D video using depth layer partition method. In the proposed algorithm, we first set frame groups using cut detection algorithm. Each divided frame groups will reduce the possibility of error propagation in the process of motion estimation. Depth image generation is the core technique in 2D/3D conversion algorithm. Therefore, we use two depth map generation algorithms. In the first, segmentation and motion information are used, and in the other, edge directional histogram is used. After applying depth layer partition algorithm which separates objects(foreground) and the background from the original image, the extracted two depth maps are properly merged. Through experiments, we verify that the proposed algorithm generates reliable depth map and good conversion results.