• Journal of Broadcast Engineering
• /
• v.21 no.6
• /
• pp.929-943
• /
• 2016

This paper proposes the rate control algorithm based on the S-JND (Saliency-Just Noticeable Difference) model for considering perceptual visual quality. The proposed rate control algorithm employs the S-JND model to simultaneously reflect human visual sensitivity and human visual attention for considering characteristics of human visual system. During allocating bits for CTU (Coding Tree Unit) level in a rate control, the bit allocation model calculates the S-JND threshold of each CTU in a picture. The threshold of each CTU is used for adaptively allocating a proper number of bits; thus, the proposed bit allocation model can improve perceptual visual quality. For performance evaluation of the proposed algorithm, the proposed algorithm was implemented on HM 16.9 and tested for sequences in Class B and Class C under the CTC (Common Test Condition) RA (Random Access), Low-delay B and Low-delay P case. Experimental results show that the proposed method reduces the bit-rate of 2.3%, and improves BD-PSNR of 0.07dB and bit-rate accuracy of 0.06% on average. We achieved MOS improvement of 0.03 with the proposed method, compared with the conventional method based on DSCQS (Double Stimulus Continuous Quality Scale).

• The KIPS Transactions:PartC
• /
• v.11C no.6 s.95
• /
• pp.773-780
• /
• 2004

In this paper, we measured the transmission characteristics of a MPEG2 and a DV that are typical stream-type traffics on the very high speed network and carried out the subjective evaluation of end users for these stream-types. In the subjective evaluation of these stream-type data, video quality evaluation is based on ITU-R BT.500-1 and audio qualify evaluation is based on ITU-R BS.1116-1. Also experiment method to acquire the subjective evaluation of end users is selected the 5 grades method of DSCQS. Under the same condition, in case of MPEG2, the evaluation grade of the video and the audio duality becomes deteriorated at the load rate of $54\%$ that network traffic increases rapidly. In case of DV the evaluation grade of video duality began decrease, but the degree of the change was slower than MPEG2 at the same load rate. Moreover the subjective evaluation grade of end users was superior to load rate $70\%$ in case of DV audio quality, traffic and QoS control that consider the subjective evaluation of end user is required. Conclusively, in case of MPEG2, we can perform traffic control that only use the actual measurement values on the network. However in case of DV, we can perform traffic control that the actual measurement values on the network and the subjective evaluation of end users are considered at the same time.

• Journal of Broadcast Engineering
• /
• v.25 no.3
• /
• pp.313-324
• /
• 2020

In this paper, we propose a motion vector prediction method that increases the coding efficiency at the boundary of an image by utilizing the 360 video characteristic. In the current VVC method, the location of a neighbor block is excluded from the candidate list for inter prediction in case that it is out of boundary. This can reduce coding efficiency as well as subject quality. To solve this problem, we construct new candidates adding the location of the neighbor block at the boundary of the picture from already decoded information based on the projection method for 360 video coding. To evaluate the performance of the proposed method, we compare with VTM6.0 and 360Lib9.1 under Random Access condition of JVET-360 CTC. As a result, the coding performance shows a BD-rate reduction of 0.02% on average in luma component and 0.05%, 0.06% on average in chroma components respectively, without additional computational complexity. The coding performance at the picture boundary shows a BD-rate reduction of 0.29% on average in luma component and 0.45%, 0.43% on average in chroma components, respectively. Furthermore, we perform subjective quality test with the DSCQS method and obtain MOS values. The MOS value is improved by 0.03 value, and we calculate BD-MOS using MOS value and bit-rate. As a result, the proposed method improved performance by up to 8.78% and 5.18% on average.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.12C
• /
• pp.1029-1038
• /
• 2008

In this paper, we propose a method for an arbitrary-view image generation in multi-view video and methods for pre- and post-processing to compensate unattended regions in the generated image. To generate an arbitrary-view image, camera geometry is used. Three dimensional coordinates of image pixels can be obtained by using depth information of multi-view video and parameter information of multi-view cameras, and by replacing three dimensional coordinates on a two dimensional image plane of other view, arbitrary-view image can be reconstructed. However, the generated arbitrary-view image contains many unattended regions. In this paper, we also proposed a method for compensating these regions considering temporal redundancy and spatial direction of an image and an error of acquired multi-view image and depth information. Test results show that we could obtain a reliably synthesized view-image with objective measurement of PSNR more than 30dB and subjective estimation of DSCQS(double stimulus continuous quality scale method) more than 3.5 point.

• ETRI Journal
• /
• v.34 no.1
• /
• pp.17-23
• /
• 2012

This paper analyzes the feasibility of a new 3DTV broadcasting service scenario via Advanced Television Systems Committee Mobile/Handheld (ATSC-M/H). We suggest a dual-channel system in which a left-view image is encoded by MPEG-2 with HD quality and a small-sized right-view image is encoded by AVC. Also, the left view is transmitted through ATSC main channel and the right view is transmitted through ATSC-M/H channel. Although the transport stream formats of two channels are different from each other, we demonstrate that it is possible for the ATSC 2.0 decoder to synchronize the display of the left and right views when both encoders use a common wall clock and time stamp. We also propose a program specific information descriptor which guarantees full compatibility with the conventional 2D HDTV and emerging mobile TV services. Finally, we provide the results of subjective visual quality assessment of the proposed system in support of its 3DTV service quality.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.5B
• /
• pp.451-463
• /
• 2011

QoE is defined as a quality perceived by users on a certain service. However, standard method to measure voice QoE(MOS) has been developed, but no standard method to measure video QoE has been defined. In this paper, we propose an efficient algorithm to measure video QoE s automatically for IPTV services. The proposed method selects candidate scenarios that affect the users' MOS directly, and derives weight factors for the selected scenarios. With the weight factors for the scenarios, video QoE value is calculated. For the validation of the proposed algorithm, we made degraded videos reflecting the parameters. With the degraded videos, by comparing the user perceived MOSs with the video QoEs derived by the proposed algorithm, we show that the two values are highly correlated each other.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.45 no.3
• /
• pp.37-45
• /
• 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
• /
• v.26 no.5
• /
• pp.621-642
• /
• 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.