• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1B
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• pp.8-17
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• 2004

In this paper: we propose the adaptive error concealment technique for scalable video coding over wireless network error prove environment. We prove it is very effective that Error concealment techniques proposed in this paper are applied to scalable video data. In this paper, we propose two methods of error concealment. First one is that the en·or is concealed using the motion vector of base layer and previous VOP data. Second one is that according to existence of motion vector in error position, the error is concealed using the same position data of base layer when the motion vector is existing otherwise using the same position data of previous VOP when the motion vector is 0(zero) adaptively. We show that according to various error pattern caused by condition of wireless network and characteristics of sequence, we refer decoder to base layer data or previous enhancement layer data to effective error concealment. Using scalable coding of MPEG-4 In this paper, this error concealment techniques are available to be used every codec based on DCT.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.11a
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• pp.110-111
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• 2012

본 논문에서는 깊이정보(depth-map)의 저작권 보호를 위한 영상암호화 알고리즘을 제안한다. 이 기술은 일반적인 자연영상과 유사한 화소분포로 표현이 되는 깊이정보 영상의 데이터 일부분을 암호화하여 전체 영상데이터의 시각적인 보안을 확보한다. 실험결과 제안한 영상암호화 알고리즘은 깊이정보 데이터의 일부분만을 암호화하여 전체 깊이정보 영상의 데이터를 효과적으로 은닉하는 것을 확인하였다.

• Journal of Internet Computing and Services
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• v.23 no.2
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• pp.61-70
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• 2022

General users who use smartphone apps often use the Vault app to protect personal information such as photos and videos owned by individuals. However, there are increasing cases of criminals using the Vault app function for anti-forensic purposes to hide illegal videos. These apps are one of the apps registered on Google Play. This paper proposes a methodology for extracting feature points through XML-based keyword frequency analysis to explore Vault apps used by criminals, and text mining techniques are applied to extract feature points. In this paper, XML syntax was compared and analyzed using strings.xml files included in the app for 15 hidden Vault anti-forensics apps and non-hidden Vault apps, respectively. In hidden Vault anti-forensics apps, more hidden-related words are found at a higher frequency in the first and second rounds of terminology processing. Unlike most conventional methods of static analysis of APK files from an engineering point of view, this paper is meaningful in that it approached from a humanities and sociological point of view to find a feature of classifying anti-forensics apps. In conclusion, applying text mining techniques through XML parsing can be used as basic data for exploring hidden Vault anti-forensics apps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6C
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• pp.349-354
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• 2011

Passive millimeter wave imaging has the capability of detecting concealed objects under clothing. Also, passive millimeter imaging can obtain interpretable images under low visibility conditions like rain, fog, smoke, and dust. However, the image quality is often degraded due to low spatial resolution, low signal level, and low temperature resolution. This paper addresses image registration and fusion between passive millimeter images and visual images. The goal of this study is to combine and visualize two different types of information together: human subject's identity and concealed objects. The image registration process is composed of body boundary detection and an affine transform maximizing cross-correlation coefficients of two edge images. The image fusion process comprises three stages: discrete wavelet transform for image decomposition, a fusion rule for merging the coefficients, and the inverse transform for image synthesis. In the experiments, various types of metallic and non-metallic objects such as a knife, gel or liquid type beauty aids and a phone are detected by passive millimeter wave imaging. The registration and fusion process can visualize the meaningful information from two different types of sensors.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.267-274
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• 2015

In this paper the optimal structure of a neural network based on OpenCV for a golf ball recognition and the intensity of ROI(Region Of Interest) are calculated. The system is composed of preprocess, image processing and machine learning, and a learning model is obtained by multi-layer perceptron using the inputs of 7 Hu's invariant moments, box ration extracted by vertical and horizontal length or ${\pi}$ calculated by area of ROI. Simulation results show that optimal numbers of hidden layer and the node of neuron are selected to 2 and 9 respectively considering the recognition rate and running time, and optimal intensity of ROI is selected to 200.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.266-270
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• 2006

In this paper, we propose the human identification system based on Hidden Markov model using gait. Since each gait cycle consists of a set of continuous motion states and transition across states has probabilistic dependences, individual gait can be modeled using Hidden Markov model. We assume that individual gait consists of N discrete transitions and we propose gait feature representation, Modified Motion Silhouette Image (MMSI) to represent and recognize individual gait. MMSI is defined as a gray-level image and it provides not only spatial information but also temporal information. The experimental results show gait recognition performance of proposed system.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.1104-1107
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• 2008

These people where generally the image or the document nik technique silver document image, against the digital data of audio back all type the research is advanced being used with objective and the use which are various, is a d. Needs a low-end leveling instrument security text from the research which it sees and with substitution quantity the silver nik being simple it will be able to deliver the technique which is simple it embodied. It combined the text image first and the nose which is in the collar image of 24 bit depth which will reach ting it did and it rehabilitatedded and a higher officer technique and the result it used that the loss ratio of the text image to analyze is slight it was ascertained.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.1036-1043
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• 2005

In this paper, we propose a sequential motion vector recovery algorithm for H.264 video coding standard. Motion vectors of H.264 video coding standard cover relatively smaller areas than other standard, since motion estimation of H.264 takes place in the fashion of variable block size. Therefore, the correlation of motion vectors between neighboring blocks increases as the block size of motion estimation is lowered. Under the framework of sequential recovery, we introduce a motion vector recovery using $\alpha$-trimed mean filter. Experimental results show that proposed algorithm is useful in real time video delivery .with nearly comparable or better visual quality than previous approaches such as macro block boundary matching and Lagrage interpolation.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.443-446
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• 2000

인간은 일상 생활에서 제스처, 표정과 같은 비언어적인 수단을 이용하여 수많은 정보를 전달한다. 따라서 자연스럽고 지적인 인터페이스를 구축하기 위해서는 제스처 인식에 관한 연구가 매우 중요하다. 본 논문에서는 영상 시퀸스의 각 영상들이 가지고 있는 정적인 양이 아닌, 영상과 이웃하는 영상들의 변화량을 수치적으로 측정하고 이를 주성분 분석법(PCA : Principal Component Analysis)과 은닉 마르코프 모델(HMM : Hidden Markov Model)을 이용하여 인식하는 방법을 소개한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.151-154
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• 2004

의미 없는 커버 영상에 비밀 메시지를 몰래 숨겨 송/수신자간에 서로 비밀 통신을 할 수 있는 기술인 스테가노그라피 기법을 제안한다. 제안 방식은 커버 영상을 연속 두 픽셀 단위의 블록으로 나누고, 블록내 두 픽셀간의 차분 값과 양자화 범위를 이용하여 비밀 메시지를 은닉시킨다. 특히, 비밀 양자화 범위를 사용하기 때문에 제 3자에 의해 비밀 메시지가 해독되는 것을 방지할 수 있다. 또한 제안 방식은 비밀 메시지가 삽입된 스테고 영상의 화질이 비가시적임을 다양한 영상을 이용하여 시험해 본 결과 그 유효성을 확인할 수 있었다.