• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.584-595
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• 2012

Recently, 3D stereoscopic video and HTTP adaptive streaming technologies have received a lot of attention from relevant industrial fields and markets in terms of multimedia contents and delivery services, respectively. It is expected that promising and marketable service models can be created by means of these noticeable two technologies. However, current standard specifications do not provide a method for organized connection between those two technologies. 3D stereoscopic video services are weighted in broadcasting and storage services that are only available under environments in which the network bandwidth is guaranteed or free. Also, HTTP adaptive streaming technologies only provide plain 3D service methods that are dependent on particular Codec. Therefore, this paper proposes 3D video delivery format for HTTP adaptive streaming service which enables stable and seamless display for various stereoscopic video sequences over internet networks. The proposed technology is designed on the basis of Stereoscopic Video Application Format which is a service-oriented standard specification for storing stereoscopic video sequences. Also, this delivery format is directly applicable over DASH that is the representative standard technology for HTTP adaptive streaming services. The delivery format proposed in this paper has been submitted to MPEG and it has been accepted as a working draft, thus it expected to pave the way for practical industrialization in relevant fields from now on.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.102-104
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• 2011

최근 비디오 스트리밍과 대화형 비디오 서비스 등과 같은 광대역 멀티미디어 서비스를 지원하기 위하여 Wimax와 같은 4G 무선네트워크 시스템 기술이 발전해 왔다. 4G 무선네트워크의 OFDM(Orthogonal Frequency Division Multiplexing)과 MIMO(multi Input Multi Output)은 사용자들에게 매우 유연한 QoS(Quality of Service) 서비스를 제공해 줄 수 있다.[1] 이 논문에서는 다양한 네트워크 상황에서 멀티캐스트 그룹에게 효율적인 방법으로 통신 자원을 할당하기 위해 OFDM 방법을 사용 하였다. 이에 본 논문에서는 한 셀(cell) 내의 서로 다른 멀티캐스트의 그룹의 다른 SNR(Signal to noise Ratio)의 사용자 분포에 따른 적응적인 scalable 비디오 멀티캐스트 방식을 제안한다. 더 나은 수신율을 가진 사용자는 최적의 MCS(Modulation and Coding Scheme) 할당을 통해 서로 다른 화질의 scalable 비디오 계층 중 높은 해상도의 비디오를 받을 수 있다. 논문에서는 전체 전송률을 최적화 하는 대신 전송받은 전체 비디오의 평균 화질을 최적화하는 방법을 제안한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.02a
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• pp.147-150
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• 2008

현재의 비디오 카메라는 인간의 눈으로 볼 수 있는 것과 동일한 화질의 비디오 영상을 얻을 수 없다. 인간의 눈은 움직이는 물체에 중점을 두고 초점을 맞추는 시각적 특성을 가진다. 하지만 현재의 비디오 카메라 시스템은 영상에 대한 인간의 눈의 시각적 특성에 대한 고려 없이 조리개와 렌즈의 조절 작업이 이루어진다. 본 논문은 이러한 비디오 카메라 시스템의 개선을 위해 인간의 눈의 시각적 특성에 기반을 둔 실시간 피사체 적응 비디오 카메라 시스템을 제안한다. 제안하는 알고리즘은 영상내에서 움직임을 가진 물체를 찾아낸 뒤, 이것에 가중치를 두고 조리개와 초점제어 작업의 순서로 이루어진다. 움직이는 물체는 영상 코덱의 움직임 정보를 파악하여 찾아내었다. 제안된 알고리즘은 프로그램언어로 구현되었으며, 초점거리와 조리개제어가 가능한 카메라와 PC를 사용하여 영상을 분석, 검증하였다.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7C
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• pp.654-662
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• 2009

Video streams for mobile video streaming can be encoded to fit the available network bandwidth by controlling three factors: temporal resolution, spatial resolution, and picture quality. The controlling of picture quality by modifying the quantization parameter (QP) is most widely used. In this paper, we demonstrate that reducing the spatial resolution adaptively can be more efficient in terms of picture quality and energy consumption in low bit-rate environment, and present a model to find the optimal spatial resolution for the available bandwidth. Adaptive spatial resolution control scheme is especially effective when the bandwidth between the video server and the mobile device varies considerably with time, and when the mobile device is sensitive to energy consumption. Our scheme can improve the picture quality by approximately O.5dB and reduce energy consumption by more than 50% compared to the conventional video coding in low bit-rate environment.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.12
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• pp.1329-1336
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• 2015

Due to the advances in hardware technologies for low-power CMOS cameras, there have been various researches on wireless video sensor network(WVSN) applications including agricultural monitoring and environmental tracking. In such a system, its core technologies include video compression and wireless transmission. Since data of video sensors are bigger than those of other sensors, it is particularly necessary to estimate precisely the traffic after video encoding. In this paper, we present an estimation method for the encoded video traffic in WVSN networks. To estimate traffic characteristics accurately, the proposed method first measures complexities of frames and then applies them to the bit rate estimation adaptively. It is shown by experimental results that the proposed method improves the estimation of bit rate characteristics by more than 12% as compared to the existing method.

• The KIPS Transactions:PartA
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• v.16A no.5
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• pp.389-394
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• 2009

Lately the usage of multimedia equipment with small LCD displays is rapidly increasing. Although many people use devices like this, videos intended for TV or HDTV are sent to these mobile devices. Therefore cases where it is hard for the user to view the desired scenes are growing more frequent. Currently, most services simply reduce the size of the content to fit the screen when they offer it for mobile devices. However, especially with sports broadcasts, there are many areas that cannot be seen very well because it was simply reduced in size. We therefore consider this weakness and are researching how to let the user choose an area of interest and then sending it to the user in a way that fits the device. In this paper, we address the problem of video delivery and personalization. For the delivered video content, we suggest the UP-SAM User Personalized Context-Aware Service Adaptation Middleware) model that uses the video content description and MPEG-21 multimedia framework.

• Journal of Korea Multimedia Society
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• v.17 no.1
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• pp.26-33
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• 2014

Video retrieval and indexing are performed by comparing feature similarities between key frames in shot after detecting a scene change and extracting key frames from the shot. Typical image features such as color, shape, and texture are used in content-based video and image retrieval. Many approaches for integrating these features have been studied. However, the issue of these approaches is how to appropriately assign weighting of key frame features at query time. Therefore, we propose a new video retrieval method using adaptively weighted image features. We performed computer simulations in test databases which consist of various kinds of key frames. The experimental results show that the proposed method has better performance than previous works in respect to several performance evaluations such as precision vs. recall, retrieval efficiency, and ranking measure.

• 전기의세계
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• v.54 no.7
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• pp.18-23
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• 2005

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1996.06a
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• pp.435-438
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• 1996