• ETRI Journal
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• 제36권2호
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• pp.253-263
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• 2014

In the near future, traditional narrow and fixed viewpoint video services will be replaced by high-quality panorama video services. This paper proposes a visual-attention-aware progressive region of interest (RoI) trick mode streaming service (VA-PRTS) that prioritizes video data to transmit according to the visual attention and transmits prioritized video data progressively. VA-PRTS enables the receiver to speed up the time to display without degrading the perceptual quality. For the proposed VA-PRTS, this paper defines a cutoff visual attention metric algorithm to determine the quality of the encoded video slice based on the capability of visual attention and the progressive streaming method based on the priority of RoI video data. Compared to conventional methods, VA-PRTS increases the bitrate saving by over 57% and decreases the interactive delay by over 66%, while maintaining a level of perceptual video quality. The experiment results show that the proposed VA-PRTS improves the quality of the viewer experience for interactive panoramic video streaming services. The development results show that the VA-PRTS has highly practical real-field feasibility.

• 한국통신학회논문지
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• 제36권11C호
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• pp.655-661
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• 2011

다양한 네트워크 환경에서 적응적인 서비스 품질을 제공할 수 있는 H.264 SVC 전송에 대한 연구가 활발하다. 본 논문은 H.264 SVC의 무기준법 객관적 화질 평가 방법으로서, H.264 SVC의 계층성을 이용한 품질 평가 지표를 제안한다. 제안하는 지표는 패킷 손실의 위치에 따라 움직임 벡터, 계층적 예측 구조에 의한 에러 전파 패턴, 양자화 파라미터, 영향을 받은 영상프레임 수 등 에러를 반영한 인지적 화질 평가를 예측한다. 제안하는 품질평가 지표는 사람의 인지적인 영상 품질을 반영한 객관적 지표이며 이 지표를 주관적 화질평가 결과인 DMOS와의 상관관계를 통해 성능을 검증하였다.

• 디지털융복합연구
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• 제10권6호
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• pp.197-203
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• 2012

본 논문에서는 IPTV 멀티캐스팅 서비스에서 네트워크 부하증가에 따른 영상품질을 평가하기 위해 유럽형 디지털 영상품질 표준 측정규격인 ETSI(European Telecommunication Standard Institute) TR 101 290을 이용하여 실험 측정한 결과를 제출하였다. 실험결과를 통해 IPTV에서의 영상품질과 ETSI TR 101 290 측정방식과는 밀접한 상관관계가 있음을 증명하였고 기존의 영상품질 평가방식에서 알 수 없었던 요소를 정확하게 평가할 수 있음을 증명하였다.

• 한국멀티미디어학회논문지
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• 제21권10호
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• pp.1182-1194
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• 2018

The Dynamic Adaptive Streaming over HTTP(DASH) is envisioned to evolve to meet an increasing demand on providing seamless video streaming services in the near future. The DASH performance heavily depends on the client's adaptive quality selection algorithm that is not included in the standard. The existing conventional algorithms are basically based on a procedural algorithm that is not easy to capture and reflect all variations of dynamic network and traffic conditions in a variety of network environments. To solve this problem, this paper proposes a novel quality selection mechanism based on the Deep Q-Network(DQN) model, the DQN-based DASH Adaptive Bitrate(ABR) mechanism. The proposed mechanism adopts a new reward calculation method based on five major performance metrics to reflect the current conditions of networks and devices in real time. In addition, the size of the consecutive video segment to be downloaded is also considered as a major learning metric to reflect a variety of video encodings. Experimental results show that the proposed mechanism quickly selects a suitable video quality even in high error rate environments, significantly reducing frequency of quality changes compared to the existing algorithm and simultaneously improving average video quality during video playback.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1247-1252
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• 2004

A objective quality assessment for the evaluation performance of a video transmission system as a basic step for construction of digital video transmission system between the spots and headquarter. Due to a limit of an analog video transmission system and the developments of various digital media and digital video standards, the need of introduce of a digital system are increased gradual1y, At this points. previously performance evaluations are performed and the quality assessment is the most important thing. We can be divided quality assessment method by the subjective quality assessment and objective quality assessment. The subjective quality assessment method has some problems which are required high cost and much time to evaluate the quality, And because existing objective quality assessment method such that PSNR are based on an analog form, the correlation with subjective data is very low. Therefore we design a new objective quality assessment method using Gabor wavelet transform reflecting HVS(Human Visual System), Designed objective quality assessment method is superior to other objective method such that PSNR or EPSNR In this paper, we proposed objective quality assessment using Gabor wavelet can be used for performance evaluation and verification of video transmission system.

• ETRI Journal
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• 제26권4호
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• pp.332-343
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• 2004

One of the recent and most significant technical properties can be expressed as "digital convergence," which is helping lead the technical paradigm into a ubiquitous environment. As an initial trial of realizing a ubiquitous environment, the convergence between broadcasting and telecommunication fields is now on the way, where it is required to develop a scalable video coding scheme for one-source and multi-use media. Traditional scalable video coding schemes have, however, limitations for higher stable picture quality especially on the region of interest. Therefore, this paper introduces an adaptive scanning method especially designed for a higher regional-stable picture quality under a ubiquitous video coding environment, which can improve the subjective quality of the decoded video by most-preferentially encoding, transmitting, and decoding the top-priority image information of the region of interest. Thus, the video can be more clearly visible to users. From various simulation results, the proposed scanning method in this paper can achieve an improved subjective picture quality far better than the widely used raster scan order in conventional video coding schemes, especially on the region of interest, and without a significant loss of quality in the left-over region.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.31-40
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• 2021

The multi-channel video streaming system is an essential device for future ground combat vehicles. For the system, the application of digital interfaces is required instead of the direct analog method to support selectable multiple channels. However, due to the characteristics of the digital interfaces that require en/decoding and signal conversion, the system should support the ability to adapt to quality and delay requirements depending on how video data is utilized. To support addressed issue, this study designs and emulates the multi-channel compressed-video streaming system of ground combat vehicle's fire control system based on commercial standards. Using the system, this study analyzes the quality of video according to the rotational speed of the acquisition device and Glass-to-Glass (G2G) delay between video acquisition and display devices according to video compression rates. Through these experiments and analysis, this paper presents the design direction of the system having scalability on the latest technology while providing high-quality video data streaming flexibly.

• 한국통신학회논문지
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• 제36권4B호
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• pp.314-321
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• 2011

영상 품질의 주관적 측정을 위한 다양한 표준 방법들이 제시되었으나, 이들 방법들은 원본 기준 영상이 존재하는 환경에서 10초 내외의 짧은 시간의 시청을 기반으로 한다. 그러나, IPTV 시청 환경에서는 장시간의 시청(예를들어 30분이상)이 이루어지므로, 표준 방법들에서의 10초 시간 주기의 평가는 현실적으로 적절하지 못하다. 본 논문에서는 IPTV 제공 환경에서 주관적 화질 평가를 위하여, 평가 주기 변화가 MOS에 미치는 영향을 분석하고 IPTV의 주관적 화질 평가에 적합한 평가 주기를 선정하기 위한 방안을 제시한다.

• 한국전자통신학회논문지
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• 제14권2호
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• pp.331-338
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• 2019

인터넷을 통한 영상 서비스의 비중이 점점 높아지고 있다. 인터넷을 통한 스트리밍 형태로 제공되는 영상서비스는 전송 과정에서 품질이 저하될 수 있기 때문에 품질 평가 및 관리가 매우 중요하다. 현재 영상 서비스에 대한 품질 관리는 특정 파라미터들의 측정값에 기초한 객관적 방법이 널리 사용되고 있다. 그러나 영상 서비스의 품질은 사람이 체감하는 품질이기 때문에 본질적으로 주관적인 측정이 더 이상적이라 할 수 있다. 따라서 본 논문에서는 모바일 환경에서 주관적 방법이 가지는 한계점을 극복할 수 있는 영상 서비스 품질 관리 방안을 제안하고 이를 위한 시스템을 설계한다. 제안하는 방법은 향후 모바일 환경에서 영상 서비스를 보다 효율적으로 관리할 수 있는데 기여할 것으로 기대된다.

• 한국멀티미디어학회논문지
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• 제23권12호
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• pp.1447-1453
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• 2020

In this paper, we propose a method for no-reference quality assessment of sports videos using 3D shearlet transform and deep residual neural networks. In the proposed method, 3D shearlet transform-based spatiotemporal features are extracted from the overlapped video blocks and applied to logistic regression concatenated with a deep residual neural network based on a conditional video block-wise constraint to learn the spatiotemporal correlation and predict the quality score. Our evaluation reveals that the proposed method predicts the video quality with higher accuracy than the conventional no-reference video quality assessment methods.