• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.3
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• pp.64-73
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• 2008

In this paper, we propose a novel objective video quality assessment method from encoded H.264/AVC.. Conventional algorithms have been proposed to assess video/image quality with image frames reconstructed in a decoder side. On the other hand, the proposed assessment is conducted with the syntax elements which are embedded in a bitstream. The proposed BS-based algorithm makes use of the statistics of boundary strength(BS) which are employed in the H.264/AVC. The proposed algorithm has lower computational complexity than conventional methods, EPSNR and Blockiness, resulting that it can accomplish assessment of the video quality in real time. Furthermore, the accuracy of the proposed video quality assessment is about 32% and 65% better than several conventional algorithms.

• Proceedings of the IEEK Conference
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• summer
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• pp.128-132
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• 2004

In this paper, we propose a new image quality assessment scheme considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform, which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

• Journal of Broadcast Engineering
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• v.12 no.2
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• pp.177-184
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• 2007

In this paper, we compared two subjective assessment methods DSCQS(Double Stimulus Continuous Quality Scale method) and ACR(Absolute Category Rating). These methods are widely used in order to evaluate video quality for multimedia application. We performed subjective quality tests using DSCQS and ACR methods. The subjective scores obtained by the DSCQS and ACR methods show that these methods are highly correlated in terms of MOS(Mean Opinion Score) and have slightly lower correlation in terms of DMOS(Difference Mean Opinion Score). The results indicate that ACR method is an effective subjective quality assessment method, which shows compatible performance with DSCQS method and can evaluate a larger number of video sequences.

• Journal of Broadcast Engineering
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• v.12 no.3
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• pp.242-249
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• 2007

Recently, International Telecommunication Union approved several methods for objective video quality measurements to be included in international standards. These methods are mainly developed to measure quality of digital video on professional CRT monitors. In this paper, we performed subjective tests in order to examine the applicability of the standard quality assessment methods for different display monitors such as common CRT, PDP, and LCD TV monitors as well as professional CRT monitors. Subjective testing on different display monitors shows that there exist relatively high correlations between the various display monitors, which indicates the standard quality assessment methods can be used on the display monitors under the given conditions of subjective duality assessment.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.909-910
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• 2008

For evaluating the performance of some codecs, many researchers have study and develop new objective video quality assessments. However, it's not sufficient for evaluating the temporal feature of video data yet, which is a distinguishable and representative characteristic when compared with other multimedia. This paper propose the method to apply the weight to SSIM (Structural SIMilarity) according to the cognitive psychological feature. And, we presented that the performance of objective video quality assessment applied the weight to SSIM by using the proposed method is superior to one of original SSIM.

• Journal of Broadcast Engineering
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• v.2 no.1
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• pp.24-35
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• 1997

Basic and transmission video quality testing was performed in real-time mode using hardware video codec based on MPEG-2 MP@ML standard including subsequent transmitting and receiving satellite simulator unit. The double-stimulus Impairment scale method and the double-stimulus continous quality scale method based on CCIR 500-5 were used as an evaluation method. The whole digital broadcasting satellite system consisting of MPEG-2 codec, system mux/demux, channel codec, channel, modem, antenna, etc. was put into the overall video quality testbed and the basic and transmission error quality assessment was performed at various bitrates and BER for an integrated system performance evaluation. In transmission error video quality testing, transmission error video quality maintained on average above 3.9 point on the 5-point scale. The low-bit rate quality such as film mode(@2Mbps) highly depended on the statitical characteristics of video source and maintained on average around 2.7 point.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.7
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• pp.2513-2530
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• 2021

With the fast development of information and communication technologies, video streaming services and applications are increasing rapidly. However, the network condition is volatile. In order to provide users with better quality of service, it is necessary to develop an accurate and low-complexity model for Quality of Experience (QoE) prediction of time-varying video. Memory effects refer to the psychological influence factor of historical experience, which can be taken into account to improve the accuracy of QoE evaluation. In this paper, we design subjective experiments to explore the impact of Short-Term Memory (STM) on QoE. The experimental results show that the user's real-time QoE is influenced by the duration of previous viewing experience and the expectations generated by STM. Furthermore, we propose analytical models to determine the relationship between intrinsic video quality, expectation and real-time QoE. The proposed models have better performance for real-time QoE prediction when the video is transmitted in a fluctuate network. The models are capable of providing more accurate guidance for improving the quality of video streaming services.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.416-424
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• 2013

Recently, efforts have been made to develop international standards related to 3DTV quality assessment underway in International Telecommunication Union and Video Quality Experts Group. Unlike conventional 2D displays, there are several types of 3D display monitors: passive glasses, active glasses and auto-stereoscopic. In this paper, we performed subjective video quality tests using various 3D display monitors, in order to examine whether these display monitors can produce consistent perceptual video quality scores for processed video sequences. The experimental results show that the subjective scores of those 3D monitors are highly correlated and it appears that similar subjective scores will be obtained even when different types of 3D displays are used.

• Electronics and Telecommunications Trends
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• v.33 no.3
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• pp.11-21
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• 2018

Assessment technologies regarding the perceptual quality of images and videos have been receiving significant attention, as they serve as essential tools for monitoring and improving the quality of various media services. In this paper, we review the technology trends of recent studies on the perceptual quality assessment of images and videos, and discuss the future direction of this research field.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.81-88
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• 2004

In this paper, we propose a new objective quality assessment method considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.