• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.802-812
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• 2019

With the rapid development in the field of unmanned aerial vehicles(UAVs) and drones, higher request to development of a surveillance system for a drone is putting forward. Since surveillance systems with fixed cameras have a limited range, a development of surveillance systems with a moving camera applicable to PTZ(Pan-Tilt-Zoom) cameras is required. Selecting the features for object plays a critical role in tracking, and the object has to be represented by their shapes or appearances. Considering these conditions, in this paper, an object tracking method with optical flow is introduced to track a tiny drone with a moving camera. In addition, a tracking method combined with kalman filter is proposed to track continuously even when tracking is failed. Experiments are tested on sequences which have a target from the minimal 12 pixels to the maximal 56337 pixels, the proposed method achieves average precision of 175% improvement. Also, experimental results show the proposed method tracks a target which has a size of 12pixels.

• Journal of Broadcast Engineering
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• v.10 no.3
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• pp.328-338
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• 2005

Technology for compressing low-bitrate multichannel audio coding is being standardized owing to the increasing need of consumer for multichannel audio contents. In this paper we propose the sound source location cue coding (SSLCC) for extremely compressing multichannel audio to be suitable at the narrow bandwidth transmission environment. To improve the compression capability of the conventional binaural cue coding(BCC), the SSLCC adopts the virtual source location information (VSLI) as a spatial cue parameter, a symmetric uniform quantizer, and Huffman coder. The objective and subjective assessment results show that the SSLCC provides lower bitrate and better audio quality than conventional BCC method.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.1
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• pp.100-108
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• 2003

By choosing Multicast for transmission of educational contents in the Remote Educational System, we can reduce the server load and increase network bandwidth utilization. We design and implement Multicast Middleware for the Remote Educational System in this paper. There are three characteristics in this Multicast Middleware: 1) Through Centralized Multicast Group Management for passive members, it allows a host to make multicast group, which is composed of receivers, called Group Member and who are chosen by the host, called group Maker. Because, all groups are created by the Group Maker in Centralized Group Management, Group Member's join action will be passive 2) Maintenance and recovery of multicast group information in order to restore from exception and crash; the maintenance and recovery mechanism of Group Maker is distinct from that of Group Member. 3) The mechanism which enables to transmit large size multimedia data through multicasting and remove additional copy operation through shared buffer. Fragmentation/de-fragmentation for large data delivery results in additional copy operation in user level. But by using user level shared buffer, it can be done without user Bevel copy operation. By applying to Remote Educational environment which consists of 30 PCs and Fast Ethernet, we can examine the efficiency of this middleware, which can transmit 18frames/sec movie which resolution 320 $\times$ 120 pixels, 128Kbps encoded sound data and some text data.

• Journal of Broadcast Engineering
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• v.7 no.2
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• pp.114-125
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• 2002

Although there have been a lot of researches on a video abstraction algorithm, the video abstraction tool is necessary to correctly pick up some important shots in a video because the important shots might vary on the person's subjectivity. This paper proposes a video abstraction and search system for making a video abstraction automatically or manually. Proposed system has two main components, server and client. The server generates the Metadata and makes a video abstraction file. The description for video abstraction file is based on MPEG-7. Since proposed system has a function to manually correct the results of each step, the author could produce a good video abstraction easily and efficiently. The proposed system could be used to build a digital video library.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.190-201
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• 2005

MPEG-21 has identified the need fur Event Reporting in its vision for an interoperable multimedia framework. Event Reporting is required within the MPEG-21 multimedia framework in order to provide a standardized means for sharing information about Events amongst Peers and Users. Such Events relate to Digital Items and/or Peers that interact with them. Arising from an each Event, there is the opportunity to describe what occurred. However, there are a number of difficulties in providing an accurate report about an Event. Different observers of the Event may have vastly different perspectives, needs, and focuses. They may emphasize certain elements to the detriment of others, or they may describe an Event in a way that others may find confusing. In this paper, we design how to express Event Reporting message structure and system architecture in compliance with ISO/IEC 21000-15. And we implement the system for MPEG-21 Event Reporting service.

• Journal of The Korean Association of Information Education
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• v.1 no.1
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• pp.102-108
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• 1997

The tele-teaching is not limited by the place and time at all. The tele-teaching is said to be an educational system by which we can teach some materials like images, letters and sounds as effectively as we can in the real place and time. The purpose of this paper is to study the method of tele-teaching which is one of the educational paradigm to deal with the changes in an information-oriented society. In this paper I also tryed to suggest an appropriate model of tele-teaching for University of Education.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.33-36
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• 2003

영상회의 시스템과 같은 멀티미디어 데이터 통신에서 스케일러빌리티 및 점진적인 전송을 구현하기 위해서 웨이브릿 기반의 영상을 부호화한다. 웨이브릿 기반의 동영상 부호화 기법인 SAMCoW 알고리즘은 움직임이 보상된 오차 영상의 웨이브릿 변환 계수들의 특성으로 인해 제로 트리의 무효 계수 예측이 효과적이지 못하다. 따라서 본 논문에서는 직교 웨이브릿(Forward Orthogonal wavelet)을 기반으로 스케일러빌리티 및 점진적인 전송을 지원하며, 움직임이 보상된 오차 영상의 효율적인 부호화를 위해 적응적 임계치를 이용한 대역 확산 부호화 알고리즘을 제안한다.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.1-8
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• 2007

In this paper, we developed a file system architecture for portable multimedia devices. To enhance user convenience, the information about the stored files should be easily retrieved and organized. We defined NMD (Networked MetaData), which can organize the files in networked fashion by attaching user-defined attributes and relation between files. The NMD is stored in flash memory to utilize its nonvolatile property and low-power consumption, while multimedia files are stored in hard disk, an inexpensive mass storage. The experimental implementation showed that this architecture was able to save about 10% power compared to the hard disk NMD-store.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.12-14
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• 1999

H.263+[1]는 1996년에 비디오압축 표준안으로 확정된 H.263의 확장으로 현재 널리 퍼져 있는 저 전송률의 가정용 전화선을 위한 비디오 압축에 관한 표준안으로 1988년에 확정되었다. H.263+의 기본 알고리즘은 H.263과 같으나 사용상의 편의를 위한 여러 선택모드와 이종의 네트워크환경에서 발생하는 대역폭의 변화나 에러를 위한 scalability(계층부호화)와 같은 새로운 기능이 추가되었다. 새로운 표준안에 따른 실시간 비디오 전송을 처리하기 위해서 필연적으로 하드웨어 코덱의 개발 필요성이 대두되고 있으며 실시간 비디오 코덱은 영상회의 전화기나 멀티미디어 전송시스템의 핵심기술로써 적용될 수 있다. 본 논문에서는 ITU-T H.263+의 기본모드와 새로이 추가된 선택모드 일부를 지원하는 코덱을 하드웨어 기술 언어인 VHDL(VHSIC Hardware Description Language)을 사용하여 기술하고 각 모듈과 최상의 모듈을 시뮬레이션하여 동작을 검증했다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10d
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• pp.145-147
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• 2002

본 논문에서는 내장형 리눅스 기반의 PDA(Personal Digital Assistants)를 위한 MPEG-4 비디오 재생기를 제안한다. PDA는 CPU 및 메인 메모리, 디스플레이 장치가 일반 PC에 비해 제한적이다. 현재 다양한 멀티미디어 데이터를 처리하기 위해 WinCE, Epoc, VxWorks과 같은 운영체제들이 개발되었으나, 운영체제의 크기가 크고 상용이라서 구입비용이 많이 드는 문제가 있다. 또, 기존의 MPEG-1, MPEG-2 같은 비디오 데이터는 1편의 영화를 감상하기에는 데이터의 크기가 커서 자원이 제한된 PDA에서 재생하기가 어렵다. 따라서, 본 논문에서는 실시간 운영체제인 내장형 리눅스를 탑재하여 PDA의 제한된 자원을 효율적으로 사용하도록 하며, 데이터 압축률이 뛰어난 MPEG-4 포맷의 비디오를 재생할 수 있는 내장형 리눅스기반의 MPEG-4 비디오 재생기를 제안한다. 제안하는 MPEG-4 비디오 재생기는 화상통신 및 화상회의를 이동 중에 할 수 있다. 또한 PDA를 위한 MPEG-4 스트리밍 서비스를 지원하는 시스템에 적용 가능하다.