• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.2
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• pp.11-17
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• 2010

In this paper, we propose efficient rate control algorithm for video near-lossless compression. The proposed method adjusts pixel error range using amounts of previous encoded bits and target bits at a slice encoding interval. Thus, encoded bits by the proposed method are transmitted well through limited bandwidth without overflow. Also, target bits and encoded bits can be controlled according to transmission policy. Experimental results show that our proposed method not only almost fits compression ratio, but also has better image quality.

• Journal of Internet Technology
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• v.20 no.5
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• pp.1535-1545
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• 2019

Recently, the diverse kinds of applications in multimedia computing have been developed for visual surveillance, healthcare, smart cities, and security. Video conferencing is one of core applications among multimedia applications. The Quality of Service of video conferencing is a major issue, because of limited network traffic. Video conferencing allow a large number of users to converse with each other. However, the huge amount of packets are generated in the process of transmitting and receiving the photographed images of users. Therefore, the number of packets in video conferencing needs to be reduced. Video conferencing can be conducted in virtual reality by sending only the control signals of virtual characters and showing virtual characters based on the received signals to represent the users, instead of the photographed images of the users, in real time. This paper proposes a method that determines representative photographed images by analyzing the collected photographed images of users, using KMedoids algorithm and a decision tree, and expresses the users based on the analyzed images. The decision tree used for video conferencing are generated automatically using the proposed method. Given that the behaviors in the decision tree is added or changed considering photographed images, it is possible to reproduce the decision tree by photographing the behavior of the user in real-time. In an experiment conducted, 63 consecutively photographed images were collected and a decision tree generated by using the silhouette images of the photographed images. Indices of the silhouette images were utilized to express a subject and one index was selected using a decision tree. The proposed method reduced the number of comparisons by a factor of 3.78 compared with the traditional method that uses correlation coefficient. Further, each user's image could be outputted by using only the control image table of the image and the index.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.534-542
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• 1999

A sell-designed rate control strategy can improve overall picture quality for video transmission over a constant bit rate channel and the rate control method is not a normative part of MPEG-video standard, the performance of MPEG video codec can be quite different depends on how to implement the rate control scheme. The rate control scheme proposed in MPEG show good results when scene changes is not occurred. But it has weakness that it does not properly handle scene-changed pictures. Therefore picture quality after scene change is deteriorated, and possibility of overflow occurrence becomes high. In this paper, a new method for detection of scene change occurrence using local variance and a new determination scheme for adaptive quantization parameter, mqunt, which can consider local characteristic of an image by using previously computed the local variance from the scene change detection part are proposed. IN addition, and adaptive rate control scheme which can handles scene changed picture very efficiently by scene-changed picture is proposed. Computer simulations are performed to verify the performance of the proposed algorithm. The suggested detection algorithm precisely detected scene change. And the proposed rate control scheme shows better rate control performance as compared with that of the conventional MPEG scheme.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1708-1714
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• 2010

In this paper, the full color LED billboard or a general quality improvement methods of quality gamma correction, brightness, and brightness adjustment, etc., regardless of the overall color of images uniformly bright or dark have been taken care of. The video itself, but simply expressed as a uniform brightness of a certain size, how to adjust the brightness of input video signal does not reflect the characteristics of the entire screen with just a lighter or darker line is only feeling was brought. So, unlike conventional video transmission system with new LED display technology in the histogram analysis of image data is input by the input image data by determining the luminance values of the attributes are reflected, as appropriate based on the histogram of the distribution of brightness values By controlling the LED display is expressed in the uniform image can improve the brightness control, histogram distribution of the image as full color billboards driven processing technology is proposed.

• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.381-396
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• 2017

In this paper, the perceptual rate control algorithm is studied for HEVC (High Efficiency Video Coding) encoder with bit allocation based on perceived visual quality. This paper proposes perceptual rate control algorithm which could consider perceived quality for HEVC encoding method. The proposed rate control algorithm employs adaptive bit allocation for frame and CTU level using the perceived visual importance of each CTU. For performance evaluation of the proposed algorithm, the proposed algorithm was implemented on HM 16.9 and tested for sequences in Class B under the CTC (Common Test Condition) RA (Random Access) case. Experimental results show that the proposed method reduces the bitrate of 3.12%, and improves BD-PSNR of 0.08dB and bitrate accuracy of 0.07% on average. And also, we achieved MOS improvement of 0.16 with the proposed method, compared with the conventional method based on DSCQS (Double Stimulus Continuous Quality Scale).

• Journal of Digital Convergence
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• v.10 no.5
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• pp.185-191
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• 2012

This study deals with the technical approach related to the protection of digital video contents copyright, which has currently become a major issue in the digital contents market. With the production and distribution of digital video contents rapidly increasing, various policies and technical approaches are being made in relation to the protection of intellectual property rights. The technical approach from a DRM (Digital Rights Management) perspective was made from various angles, but its limitations have also been exposed in terms of convenience and quality. In this study, rather than the existing encoding certification and watermark technologies, it introduces technical approaches from a content-based copy detection method, while suggesting a copy detection method using the representative color sequence. In particular, this study takes into consideration the distribution environment of the domestic video market and deals with the technical approach in a direction that can control the illegal distribution of high quality videos.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8B
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• pp.1424-1435
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• 2000

A bit-rate controller that can achieve a constant bit rate when coding object-based video sequences is an important part to achieve an adaptation to bit-rate constraints, desired video quality, distribution of bits among objects, relationship between texture and shape coding, and determination of frame skip or not. Therefore we design content-based bit rate controller which will be used for relevant bit-rate control. The implementation is an extension of MPEG-4 rate control algorithm which employs a quadratic rate-quantizer model. The importance of different objects in a video is analyzed and segmented into a number of VOPs which are adaptively bit-allocated using the object-based modelling. Some test sequences are observed by a number of non-experts and interests in each object are analysed. The initial total target bit-rate for all objects is obtained by using the proposed technique. Then the total target bits are jointly analyzed for preventing from overflow or underflow of the buffer fullness. The target bits are distributed to each object in view of its importance, not only of statistical analysis such as motion vector magnitude, size of object shape, and coding distortion of previous frame. The scheme is compared with the rate controller adopted by the MPEG-4 VM8 video coder by representing their statistics and performance.

• Journal of the Korea Society of Computer and Information
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• v.21 no.7
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• pp.17-22
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• 2016

In this paper we propose a novel QoE control scheme based on Service Level Agreement (SLA) which enables to guarantee the user perceived service quality of various high-quality mobile multimedia services such as mobile video streaming and real-time network games to a certain level. For this purpose, a SLA control structure is adopted to provision QoE, and a novel resource management scheme gets coupled with this control structure. Simulation results show that our proposed scheme can decrease the average delay and increase the total throughput by adjusting SLA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.307-314
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• 2003

In the general multiple video object coder, more interested objects such as speaker or moving object is consistently coded with higher priority. Since the priority of each object may not be fixed in the whole sequence and be variable on frame basis, it must be adjusted in a frame. In this paper, we analyze the independent rate control algorithm and global algorithm that the QP value is controled by the static parameters, object importance or priority, target PSNR, weighted distortion. The priority among static parameters is analyzed and adjusted into dynamic parameters according to the visual interests or importance obtained by camera interface. Target PSNR and weighted distortion are proportionally derived by using magnitude, motion, and distortion. We apply those parameters for the weighted distortion control and the priority-based control resulting in the efficient bit-rate distribution. As results of this paper, we achieved that fewer bits are allocated for video objects which has less importance and more bits for those which has higher visual importance. The duration of stability in the visual quality is reduced to less than 15 frames of the coded sequence. In the aspect of PSNR, the proposed scheme shows higher quality of more than 2d13 against the conventional schemes. Thus the coding scheme interfaced to human- eye proves an efficient video coder dealing with the multiple number of video objects.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1A
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• pp.9-17
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• 2004

Adapt ive and fixed step size PC (power control) schemes for accommodating voice, video, and data are evaluated according to the different PC command rates and their effects on integrated Voice/Video/Data are investigated. The required minimum power levels are derived as PC thresholds and the effects of PC errors on channel quality and radio 1 ink capacity are investigated. The services with high bit rates and low bit error rates can cause a significant effect on the radio link qualifies of the other types of traffic. The results show that the adapt ive step size PC scheme for voice/video/data services can achieve more capacity and cause less interference to the radio channels because less minimum PIL(Power Increment Level) is required for the specified radio link outage probability.