• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.155-158
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• 2007

In this paper, we solved the underestimation problem of PSNR, which is caused by repeated frames, by easily synchronizing original and decoded frames using the proposed marks. Also we propose full-reference system which can be applied for measuring the quality of various kinds of video communication systems, e.g. wireless handsets, mobile phones and applications for PC. In addition, we propose a new video quality assessment metric using video communication parameters, i.e. frame rate and delay. According to the experiments, the proposed metric is not only appropriate for real-time video communication systems but also shows better correlation with the subjective video quality assessment than PSNR. The proposed measuring system and metric can be effectively used for measuring and standardizing the video quality of future communications.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 춘계학술발표대회
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• pp.355-358
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• 2012

Although quality metrics for 2D video quality assessment have been proposed, the quality models on stereoscopic video have not been widely studied. In this paper, a new objective video quality metric for s tereoscopic video is proposed. The proposed algorithm consider three factors to evaluate stereoscopic video quality: blocking artifact, blurring artifact, and the difference between left and right view of stereoscopic vide o. The results show that the proposed algorithm has a higher correlation with DMOS than the others.

• ETRI Journal
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• 제38권6호
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• pp.1114-1123
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• 2016

Multi-view video plus depth (MVD) has been widely used owing to its effectiveness in three-dimensional data representation. Using MVD, color videos with only a limited number of real viewpoints are compressed and transmitted along with captured or estimated depth videos. Because the synthesized views are generated from decoded real views, their original reference views do not exist at either the transmitter or receiver. Therefore, it is challenging to define an efficient metric to evaluate the quality of synthesized images. We propose a novel metric-the reduced-reference quality metric. First, the effects of depth distortion on the quality of synthesized images are analyzed. We then employ the high correlation between the local depth distortions and local color characteristics of the decoded depth and color images, respectively, to achieve an efficient depth quality metric for each real view. Finally, the objective quality metric of the synthesized views is obtained by combining all the depth quality metrics obtained from the decoded real views. The experimental results show that the proposed quality metric correlates very well with full reference image and video quality metrics.

• 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.

• 방송공학회논문지
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• 제12권2호
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• pp.102-111
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• 2007

다양한 멀티미디어 영상 서비스 환경에 최적의 서비스 품질(Quality of Service, QoS)을 제공하는 것은 중요 이슈 중 하나이다. 이를 위해서 다양한 서비스 환경에 따라 쉽게 확장 가능한 영상 부호화 기술과 영상의 품질을 계량적으로 표현하는 기술이 필요하다. 본 논문에서는 확장 가능한 영상 부호화(Scalable Video Coding, SVC)에 기반한 영상에 대해 영상의 내용 특징 정보와 전 확장성, 즉 시간적, 공간적, 품질적 확장을 고려한 새로운 품질 메트릭을 제안한다. 실험 결과, 제안된 품질 메트릭은 측정된 주관적 점수와의 상관계수(correlation coefficient)가 평균 0.9이상으로 우수한 성능을 증명하였다. 본 논문에서 제안한 메트릭은 영상의 다양한 프레임 율, 화질, 공간 해상도, 그리고 모션 특성과 같은 부호화 조건에 따른 품질측정이 가능하여 최적의 부호화 조건을 결정할 수 있다.

• Journal of Communications and Networks
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• 제7권3호
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• pp.235-242
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• 2005

Multimedia applications and especially encoded video services, are expected to playa major role in the 3rd generation (3G) and beyond mobile communication systems. Given that future service providers are expected to provide video applications at various price and quality levels, quick and economically affordable methods for preparing/encoding the offering media at various qualities are necessary to be developed. This paper presents a method for objective evaluation of the perceived quality of MPEG­4 video content, based on a quantification of subjective assessments. Showing that subjectively derived perceived quality of service (PQoS) vs. bit rate curves can be successfully approximated by a group of exponential functions, the proposed method exploits a simple objective metric, which is obtained from the mean frame rate vs. bit rate curves of an encoded clip. The validity of this metric is assessed by comparing subjectively derived PQoS results to the corresponding ones, which come from the proposed objective method, showing that the proposed technique provides satisfactory PQoS estimation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권5호
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• pp.1388-1399
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• 2012

This paper proposes a quality metric based on a No-Reference Bitstream (NR-B) having least computational complexity for the assessment of the human-perceptual quality of H.264 encoded video. The proposed NR-B method performs a modeling of encoding distortion with three bit-stream information (i.e. frame-rate, motion-vector, and quantization-parameter) that can be directly extractable from the encoded bitstream and does not require additional complex processing of final pictures. From performance evaluation using 165 compressed video sequences, the experiment results show that the proposed metric has a higher correlation with subjective quality than is achieved with other comparable methods.

• 방송공학회논문지
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• 제13권2호
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• pp.179-187
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• 2008

본 논문에서는 영상 특성에 제약 없이 적용 가능한 SVC 기반 범용 품질 메트릭을 제안한다. 이종 환경에서의 비디오 콘텐츠 소비가 증가하면서 서비스 품질(Quality of Service, QoS)은 중요한 이슈 중 하나가 되었다. 또한 스케일러블 비디오 코딩(Scalable Video Coding, SVC)은 하나의 부호화된 비트스트림이 공간적, 시간적 그리고 품질적으로 다양한 확장이 가능하다는 장점을 이유로 이종 환경에서 적응성이 높은 영상 부호화 기술로 주목받고 있다. 제한된 환경에서의 서비스 품질 보장을 위해서는 서비스의 사용 주체인 사람이 느끼는 주관적 비디오 품질이 고려되어야 한다. 주관적 품질은 영상의 시간적, 공간적 특성 모두에 영향을 받기 때문에 영상의 특성에 대한 고려 역시 중요하다. 제안하는 방법의 효율성은 실험을 통해 측정된 주관적 품질 값과 제안된 품질 메트릭을 이용해 측정된 품질 지수 사이의 상관계수를 이용하여 검증하였으며 제안하는 품질 메트릭은 SVC의 품질 확장 결정 기준으로 사용될 수 있다.

• 디지털산업정보학회논문지
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• 제18권4호
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• pp.13-21
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• 2022

Recently, in wireless video sensor networks(WVSN), various schemes for efficient video data transmission have been studied. In this paper, a layer based cooperative relaying(LCR) algorithm is proposed for minimizing scalable video transmission distortion from packet loss in WVSN. The proposed LCR algorithm consists of two modules. In the first step, a parameter based error propagation metric is proposed to predict the effect of each scalable layer on video quality degradation at low complexity. In the second step, a layer-based cooperative relay algorithm is proposed to minimize distortion due to packet loss using the proposed error propagation metric and channel information of the video sensor node and relay node. In the experiment, the proposed algorithm showed that the improvement of peak signal-to-noise ratio (PSNR) in various channel environments, compared to the previous algorithm(Energy based Cooperative Relaying, ECR) without considering the metric of error propagation.The proposed LCR algorithm minimizes video quality degradation from packet loss using both the channel information of relaying node and the amount of layer based error propagation in scalable video.

• IEIE Transactions on Smart Processing and Computing
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• 제2권5호
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• pp.255-265
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• 2013

3DTV is expected to be a promising next-generation broadcasting service. On the other hand, the visual discomfort/fatigue problems caused by viewing 3D videos have become an important issue. This paper proposes a perceptual quality assessment metric for a stereoscopic video (SV-PQAM). To model the SV-PQAM, this paper presents the following features: temporal variance, disparity variation in intra-frames, disparity variation in inter-frames and disparity distribution of frame boundary areas, which affect the human perception of depth and visual discomfort for stereoscopic views. The four features were combined into the SV-PQAM, which then becomes a no-reference stereoscopic video quality perception model, as an objective quality assessment metric. The proposed SV-PQAM does not require a depth map but instead uses the disparity information by a simple estimation. The model parameters were estimated based on linear regression from the mean score opinion values obtained from the subjective perception quality assessments. The experimental results showed that the proposed SV-PQAM exhibits high consistency with subjective perception quality assessment results in terms of the Pearson correlation coefficient value of 0.808, and the prediction performance exhibited good consistency with a zero outlier ratio value.