• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3157-3164
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• 1999

In this paper, we propose a hybrid watermarking algorithm for an MPEG bitstream. Our hybrid watermarking technique uses a spread spectrum technique for I-frames and a motion vector technique for P- and B-frames. Thus, the proposed algorithm makes it possible to watermark all MPEG frames. By applying this technique, it is possible not only to protect intellectual property rights but also be robust against various kinds of attacks to remove watermark. And this scheme requires only partial decoding of an MPEG bitstream, so it is applicable to real-time watermarking applications.

• Broadcasting and Media Magazine
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• v.19 no.2
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• pp.80-89
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• 2014

기존 HD TV에 비해 더 높은 화질과 몰입감을 시청자에게 제공하는 UHD TV는 차세대 방송 시장의 성장을 주도하고 있다. 따라서 UHD 방송 시스템을 구축하기 위해 고효율 압축 부호화 기술인 HEVC 표준화, 5G 전송 기술 표준화 등 차세대 기술 연구가 콘텐츠 압축, 전송 분야에서 활발하게 진행되었다. 이러한 콘텐츠 압축, 전송 기술 분야의 괄목할 만한 연구 성과에 의해, UHD 방송을 제공하기 위한 기술적 문제는 많은 부분 해결되었다. 하지만 현재 기존 HD 방송과 차별화 되는 UHD 방송 시스템 기반의 방송 서비스 기술에 대한 연구는 많이 진행되지 않고 있다. 따라서 본 논문에서는 한 화면에서 여러 채널을 동시 시청할 수 있는 Multi-Channel View 서비스 기술에 대해서 알아보고, 이를 통해 UHD 방송의 고해상도 영상을 이용한 차별화된 사용자 맞춤형 Multi-Channel View 서비스를 구현하기 위한 연구 방향을 제시하고자 한다.

• Proceedings of the IEEK Conference
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• 2001.06d
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• pp.45-48
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• 2001

Unequal Error Protection(UP) is reasonable scheme in transmission of compressed video with low bit rate. Because it offers the error correction ability each other data according to the Source Significance Information. Hence it can also be flexible to the given channel environment on the video transmission. This paper propose the joint source channel coding through the UEP in consideration of the hierarchical structure of H.263+ based video and the influence of the transmission error. It especially proposes the error-resilient video transmission technique which can reduce complexity of channel coder & decoder by partitioning the video data with a frame. As the result of the proposed algorithm, it is possible to increase the quality of reconstructed video in the error environment without creating additional bits.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.118-122
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• 2000

Nowadays, it is popular to use the spread spectrum watermarking algorithm for still image. But there is high error probability of the retrieved watermark in the spread spectrum owing to the correlation between image and spreaded watermark sequence. In this paper, two methods are proposed. One is Ordering Map Method and the other is Alteration of Image. Based on pixel value, the order by which the spreaded watermark bits is embedded is created in Ordering Map Method. By the covariance function between image and the spreaded sequence, image is altered in Alteration of Image. Hence, bit error of retrieved watermark is clearly reduced to zero by this two method.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.1121-1124
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• 2005

Edge Histogram Descriptor는 image의 edge 분포 정보를 표현하며 방향성을 가지는 Bio Image 검색에 있어 높은 검색 성능을 나타낸다. 그러나 Bio Image의 객체 분포의 특성으로 인해 지역적 edge 분포 비교는 충분한 검색 성능을 보장하지는 못한다. 본 논문에서는 특징 block을 이용한 효율적인 검색 알고리즘을 제안한다. Local histogram으로부터 Global bin을 얻어 image의 대표 방향성을 선정하고 특징 block을 선정한다. 특징 block의 비교는 edge 분포와 함께 주요 객체의 위치 정보를 더하는 효과를 가진다. Bio Image의 검색 실험에서 제안 알고리즘은 향상된 검색 성능을 보여준다. 또한 Bio image 검색을 위한 descriptor 조합 연구에도 적용 가능하여 검색 효율을 기대할 수 있다.

• Design & Manufacturing
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• v.8 no.1
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• pp.31-34
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• 2014

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. It spends most of times in the cooling process. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating. However, if response time of temperature controller and sensor will be increased, the performance of this system will increase.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.175-177
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• 2004

The current JPEG-2000 standard is a wavelet based scheme because wavelet transform have some advantages compare to DCT transform. In compressed images, there are some image degradation factors like contrast distortion by Quantization process. This factor is very important to HVS (Human Visual System). Therefore, In this paper, we propose a new algorithm for contrast enhancement using the properties of wavelet coefficients. This algorithm is processed in the wavelet domain and so it can be applied efficiently to JPEG-2000.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.739-742
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• 2001

동영상은 각 프레임 사이에 시간적으로나 공간적으로 많은 양의 정보가 중복되어 있다. 이러한 중복 정보를 줄이는 표현 방법들 중에 하나로, 동영상을 커다란 하나의 영상으로 정합하여 중복 정보를 줄이는 모자이크 기법이 있다. 두 개 이상의 영상을 정합하기 위해서는 영상간의 카메라 파라미터가 필요한데, 본 논문에서는 Mellin 변환을 사용하여 카메라 파라미터를 구하였다. 이때 3차원 공간모델은 직교 투사법을 사용하였으며, 영상의 움직임 모델로는 4개의 파라미터(평행이동, 확대/축소, 회전)를 사용한 어파인 움직임 모델을 사용하였다. 이렇게 구현된 파노라마 영상은 동영상에서 움직이는 물체를 검출하거나 추적하고, 동영상을 편집하는데 응용될 수 있다. 또한 본 연구의 최종 목적인 3D 영상의 배경을 구현하는 데 좀 더 사실적인 영상을 제공할 수 있다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.2
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• pp.71-78
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• 1997

Markov random field models have extensively used in applications such as image segmentation and image restoration. In this paper, we consider the relation between the stationarity of parameters and the synthesized images for gauss-markov rnadom field which has the most popularly used among many MRF models. GMRF model, which is both wide-sense Markov and strict-sense markov, has AR representations and is also a kind of gibbs distribution. Therefore, we may approach in aspect of both AR models and gibbs models. We show the relation between the stationarity of parameters and the images which are synthesized by two approaching methods and derive the stationary regions of parameters in 1st order and isotropic 2nd order case.

• Journal of Broadcast Engineering
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• v.5 no.2
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• pp.188-198
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• 2000

As MPEG-2 is introduced, a new editing system that works at the compressed domain is required. It is efficient to paste the two different video sequences in the compressed domain, but after repeated pasting, the result sequence can violate MPEG-2 rate control algorithm. In other words, it causes the underflow of the buffer during the decoding time. The earlier study inserted an additional fade-in sequence but it is not natural when we make a program. In this paper, a nobel method using requantization of the underflow sequence is presented.