• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.655-661
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• 2011

The transmission issues for the scalable video coding extension of H.264/AVC (H.264 SVC) video has been widely studied. In this paper, we propose an objective video-quality assessment metric based on no-reference for H.264 SVC using scalability information. The proposed metric estimate the perceptual video-quality reflecting error conditions with the consideration of the motion vectors, error propagation patterns with the hierarchical prediction structure, quantization parameters, and number of frame which damaged by packet loss. The proposed metric reflects the human perceptual quality of video and we evaluate the performance of proposed metric by using correlation relationship between differential mean opinion score (DMOS) as a subjective quality and proposed one.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.147-154
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• 2020

In this study, four types of composite added filtration (aluminum, nickel, copper, and zinc) were combined for each thickness to evaluate dose reduction and optimal images due to X-ray attenuation. To evaluate dose and image quality. X-ray generators, Dose Area Product(DAP) and ICY programs with RQR9 standard quality were used. In the image quality evaluation element (PSNR, RMSE, SSIM), only images with PSNR value of 30 dB or more were analyzed. As a result, the best combination in dose evaluation was 3 mmAl + 0.6 mmNi (0.16µGy㎡), and the best filter in image quality evaluation was 0.9 mmAl (PSNR 34.24dB, RMSE 79.52, SSIM 0.24). In this study, the dose aspect and the image quality aspect are mentioned, So it is considered that further studies on patient's exposure dose and optimal image will be needed in the future.

• Journal of Broadcast Engineering
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• v.14 no.2
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• pp.127-133
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• 2009

With advances in video technology, many researchers are interested in video quality assessment to prove better performance of proposed algorithms. Since human visual system is too complex to be formulated exactly, many researches about video quality assessment are in progressing. No-reference video-quality assessment is suitable for various video streaming services, because of no requested additional data and network capacity to perform quality assessment. In this paper, we propose a novel no-reference video-quality assessment method with the estimation of dynamic range distortion. To measure the performance, we obtain mean opinion score (MOS) data by subject video quality test with the ITU-T P.910 Absolute Category Rating (ACR) method. And, we compare it with proposed algorithm using 363 video sequences. Experimental results show that the proposed algorithm has a higher correlation with obtained MOS.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.3
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• pp.37-45
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• 2008

Quality assessment ai s to evaluate if a distorted image or video has a good quality by measuring the difference between the original and distorted images or videos. In this paper, to assess the visual qualify of a distorted image or video, visual features of the distorted image are compared with those of the original image instead of the direct comparison of the distorted image with the original image. We use edge projections from two images as features, where the edge projection can be easily obtained by projecting edge pixels in an edge map along vertical/horizontal direction. In this paper, edge projections are obtained by using vertical/horizontal directions of gradients as well as the magnitude of each gradient. Experimental results show the effectiveness of the proposed quality assessment through the comparison with conventional quality assessment algorithms such as structural similarity(SSIM), edge peak signal-to-noise ratio(EPSNR), and edge histogram descriptor(EHD) methods.

• Journal of Broadcast Engineering
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• v.26 no.5
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• pp.621-642
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• 2021

In this paper, the subjective video quality assessment of the content quality was to examine by the assessors about the three content quality of HD, Up-scaling UHD, 4K UHD Native that is currently broadcasted. The comparative assessment was conducted using three types of TV sets, 55, 65, 75 inches, at a distance of 2.5 meters which is the distance of watching TV in general households. Among the participants who took part in the video quality evaluating experiment and the questionnaire survey, the answering data of the final 169 persons were adopted after removing the data of 4 persons who answered inadequately in the evaluation of the video quality. The effects of gender, preference of program genre, size of TV sets were analyzed statistically using SPSS 25.0 analysis package. In addition to these, the objective video quality assessment through the measuring instrument was performed, and compared with the results of subjective video quality assessment.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.1
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• pp.29-37
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• 2008

With the rapid development of display technology as well as the diversity of display, image quality assessment plays an important role in display color reproduction. The image quality has described by objective evaluation based on the physical measured data, such as contrast ratio, color reproduction range, color temperature, and gamma characteristics, etc., however, the final judgement is achieved by perceptual quality assessment of observers. Therefore, it is necessary to investigate the relationship between physical performance of display and perceptual image quality. Thus, in order to evaluate objectively the color reproduction characteristics of two mobile displays, TFT-LCD and AMOLED, we measured the darkroom contrast ratio of full screen, luminance and color temperature of full-screen white, full-screen gray and color linearity, tone reproduction of color scales for each RGB primary, and color reproduction range. Then the pair-wise comparison is implemented for image experts and naive observers not only to judge their preference on principal evaluation attributes but also to subjectively describe perceived image quality. Through two evaluation processes, we derived the objective bases that can prove the results of subjective image quality assessment by interconnecting physical factors that have influence on observers' preference judgements. Finally, this paper provided important information for improving the image quality and increasing preference from an observer's point of view.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.11a
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• pp.131-135
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• 2000

본 연구에서는 연령·조명·프로그램 종류에 따른 TV 최적 화질의 설정치를 규명하고, 최적 화질에 대한 감성구조를 규명하는 것이 목적이다. 아동, 성인 그리고 노인이 실험에 참여하였고, 세 가지 조명 조건에 따라 영화, 만화영화 (애니메이션), 드라마, 다큐멘터리의 화면이 제시되었다. 실험 참여자들은 화면을 보는 동안, 리모콘을 사용하여 가장 만족스러운 화면을 설정하였다. 또한 설정한 최적화질에 대해 감성을 평가하였다. 그 결과, 연령·조명·프로그램 종류에 따라 최적 화질에 대한 설정치가 다르게 나타났다. 화질에 대한 감성구조는 두 차원 (쾌-불쾌 및 감각특성, 미적특성)으로 나타났으며, 연령에 따라 감성구조가 다르게 나타났다.

• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.53-64
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• 2013

The existing research on the QoS of the Streaming video system(SVS) adjust the video stream being sent from the network perspective, the focus is to prevent data loss and delay. The other hand, changing the quality of the video stream will not receive the guaranteed QoS from the perspective of the users who want uniform quality. In order to solve these problems, this paper applied to ensure that the benefits in the amount of bits per frame occurs Encoder CBR streaming video is kept constant and uniform picture quality advantages of VBR streaming video VBR to CBR Encoder and CBR to VBR Decoder, Video was designed to control the playback stream for And to ensure a uniform quality of the user based on the design and implementation of uniform quality guaranteed SVS. PSNR evaluated for several characteristics of the sample video to demonstrate the superiority of the SVS ensure uniform quality, the proposed Performance evaluation of the SVS ensure uniform quality CBW the ABR from 100% to ensure uniform image quality from 85% to environmental excellence is proved.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.133-136
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• 2006

한정된 네트워크 대역폭을 가진 현재의 인터넷에서 영상의 품질을 향상시키기 위해 영상의 비트율을 높이는 것은 비용 등 여러 가지 문제로 인해 현실적으로 많은 어려움이 있다. 따라서 비록 충분하지 못한 비트율의 영상을 전송받더라도 전송받은 영상의 화질을 높이는 연구가 다양한 방법으로 진행되고 있다. 영상의 화질을 향상시키는 많은 방법 중 후처리 기법은 이러한 잡음을 효과적으로 제거 할 수 있으면서 동영상 압축 표준 복호기를 수정할 필요가 없기 때문에 좋은 해결책이 된다. 동영상의 압축 과정에서 낮은 비트율로 인해 발생하는 화질 열화 현상 중에 쉽게 완화 할 수 있고, 영상의 질이 비용 대비 높은 효율로 좋아지는 대표적인 현상이 블록화 현상이다. 일반적으로 블록화 현상은 영상의 고주파대역에서 나타나므로 본 논문에서 영상의 고주파 성분과 블록화 현상을 구분하기 위해 Sobel 마스크를 사용한다. 구분된 블록화 현상이 발생한 매크로블록의 양쪽 경계면에 4-tap 저주파 통과 필터를 사용하여 블록화 현상을 효과적으로 완화할 수 있다. 개선된 영상의 화질 평가 기법으로 신호처리 분야에서 많이 사용되는 객관적인 지표인 PSNR에 의한 평가와 함께 실제 인간의 시각을 기준으로 주관적이고 감성적인 관찰에 의한 평가를 함께 수행한다.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.283-296
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• 2013

Various video services with networks are increasingly available as smart phones, computers and IPTV are widely used. However, transmission over networks may experience transmission errors due to traffic increases and noise. As a result, video quality may suffer. Therefore, quality monitoring emerges as an important issue. In this paper, we propose a video quality assessment method using bit stream information. The video quality metric is calculated using header information and ES (elementary stream) information. To assess performance of the proposed algorithm, subjective quality assessment tests are conducted (VGA resolution). It is shown high correlation between subjective result and the proposed method.