• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3C
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• pp.140-148
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• 2011

The side information in the distributed video coding system is generated using motion compensated interpolation methods. Since the accuracy of the generated side information affects the amount of parity bits for the reconstruction of Wyner-Ziv frame, it is important to produce an accurate side information. In this paper, we analyze the informance of various side information generation methods and propose an effective side information generation technique. Also, we compare each side information generation methods from the hardware point of view and analyze the performance of distributed video coding system using various side information generation methods.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.92-103
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• 2012

In this paper, we discuss and propose a new algorithm of coding technique for scalably servicing holographic video in various decoding environment. The proposed algorithm consists of the hologram-based resolution scalable coding (HRS) and the light source-based SNR scalable coding (LSS). They are classified by the method generating and capturing hologram. HRS is a scalable coding technique for the optically captured hologram and LSS is one for the light source before generating hologram. HRS can provide the scalable service of 8 steps with the compression ratio from 1:1 to 100:1 for a $1,024{\times}1,024$ hologram. LSS can also provide the various service depending on the number of the light source division using lossless compression. The proposed techniques showed the scalable holographic video service according to the display with the various resolutions, computational power of the receiving equipment, and the network bandwidth.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.433-436
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• 2003

In this paper, the efficient motion estimation and compensation method for 3 dimensional wavelet transform is proposed. Recently, since the compression performance and scalable functionality are provided by wavelet transform, many researches have been carried out for applying to the video compression. For the temporal filtering, motion estimation and compensation techniques are used, but the unconnected pixels, which are produced by motion compensation result into the degradation of coding performance and quality of the picture. For the efficient motion compensated temporal filtering by reducing the number of these unconnected pixels, we propose the variable block size motion estimation and compensation method. Also we propose a method that determines the block size using rate-distortion optimization technique according to the local characteristics of the frame. The simulation results show the improved performances than the MPEG-4 scalable coding methods and the 3 dimensional wavelet coding methods using fixed block size motion estimation and compensation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10C
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• pp.778-786
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• 2008

The H.264/AVC video coding standard shows superior coding efficiency by adopting many new techniques. However, the encoding complexity increases greatly to achieve higher coding efficiency. Especially, the rate distortion optimization technique, which is used to decide the intra-prediction mode, increases the encoding complexity. In this paper, we propose an efficient intra-prediction mode decision method. By using the variance of pixel values and the edge direction, the computational complexity of the intra-prediction mode decision is greatly reduced.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.295-298
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• 2003

In this paper, a novel maximum a posterion (MAP) estimation for the channel decoding of H.264 codes in the presence of transmission error is presented. Arithmetic codes with a forbidden symbol and trellis search techniques are employed in order to estimate the best transmitted. And, there has been growing interest of communication, the research about transmission of exact data is increasing. Unlike the case of voice transmission, noise has a fatal effect on the image transmission. The reason is that video coding standards have used the variable length coding. So, only one bit error affects the all video data compressed before resynchronization. For reasons of that, channel needs the channel codec, which is robust to channel error. But, usual channel decoder corrects the error only by channel error probability. So, designing source codec and channel codec, Instead of separating them, it is tried to combine them jointly. And many researches used the information of source redundancy In received data. But, these methods do not match to the video coding standards, because video ceding standards use not only one symbol but also many symbols in same data sequence. In this thesis, We try to design combined source-channel codec that is compatible with video coding standards. This MAP decoder is proposed by adding semantic structure and semantic constraint of video coding standards to the method using redundancy of the MAP decoders proposed previously. Then, We get the better performance than usual channel coder's.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1663-1670
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• 2014

Recently, lots of research works have been actively focused on the DVC (Distributed Video Coding) techniques which provide a theoretical basis for the implementation of light video encoder. However, most of these studies have showed poorer performances than the conventional standard video coding schemes such as MPEG-1/2, MPEG-4, H.264 etc. In order to overcome the performance limits of the conventional approaches, several channel-divided distributed video coding schemes have been designed in such a way that some information are obtained while generating side information at decoder side and then these are provided to the encoder side, resulting in channel-divided video coding scheme. In this paper, the interpolation scheme by weighted sum of multiple motion-compensated interpolation frames is introduced and a new channel-divided DVC scheme is designed to effectively describe noisy channels based on the motion vector and its matching characteristics. Through several simulations, it is shown that the proposed method performs better than the conventional methods at low bit-rate and keeps the reconstructed visual quality constantly.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.271-275
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• 2008

Corresponding recent continuous development of multimedia technology with improved desire of using various contents, a new realistic feeling media technology is being created. Of them all, multi-view video is being researched actively as foundation technology of 3D TV, free-view point video etc. But encoding time and bit-rate are increased as view numbers are increased. In this paper we propose improved GoGOP structure to enhance the coding efficiency of multi-view video by applying methods which are using techniques such as Key frame position adjustment, dynamically changing the number of I frame and B frame. As experimental results, technique proposed in this paper reduces bit-rate having similar PSNR value compared with Anchor structure.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.12
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• pp.1581-1590
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• 1995

Recently, advanced video coding techniques using segmentation technique have been actively researched as candidates for video coding of MPEG-4 standard. The conventional segmentation techniques are unsuitable for real-time process because they have sequential structure. In this paper, we propose a new image segmentation technique using competitive learning neural network for vector quantization. The proposed segmentation procedure consist of prefiltering, primary and secondary segmentation, and a small region ellimination process. Primary segmentation segments input image in detail. Secondary segmentation merges similar region using a repetitive FSCL(Frequency sensitive competive learning) neural network. In this process, it is possible to segment an image from high resolution to low resolution by adjusting the number of repetition. Finally, small regions are merged into adjacent regions. Experimental results show that the procedure described yields reconstructed images of reasonably acceptable quality at bit rates of 0. 25 - 0.3 bit/pel.

• Journal of Broadcast Engineering
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• v.25 no.3
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• pp.338-345
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• 2020

Versatile Video Coding (VVC), which has been developing as a next generation video coding standard, has adopted various techniques to achieve more than twice the compression performance of HEVC (High Efficiency Video Coding). The recently released VVC Test Model (VTM) shows 38% Bjontegaard Delta bitrate (BD-rate) improvement and 9x/1.6x encoding/decoding complexity over HEVC. In order to reduce such increased complexity, various fast algorithms have been proposed. In this paper, gradient-based methods of fast intra mode decision and block splitting are presented. Experimental results show that, compared to VTM6.0, the proposed method gives up to 65% encoding time reduction with 3.54% BD-rate loss in All-Intra (AI) configuration.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.485-491
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• 2012

This paper proposes 'Coding Unit Tree' based on quadtree efficiently with motion vector to represent splitting information of a Coding Unit (CU) in HEVC. The new international video coding, High Efficiency Video Coding (HEVC), adopts various techniques and new unit concept: CU, Prediction Unit (PU), and Transform Unit (TU). The basic coding unit, CU is larger than macroblock of H.264/AVC and it splits to process image-based quadtree with a hierarchical structure. However, in case that there are complex motions in CU, the more signaling bits with motion information need to be transmitted. This structure provides a flexibility and a base for a optimization, but there are overhead about splitting information. This paper analyzes those signals and proposes a new algorithm which removes those redundancy. The proposed algorithm utilizes a type code, a dominant value, and residue values at a node in quadtree to remove the addition bits. Type code represents a structure of an image tree and the two values represent a node value. The results show that the proposed algorithm gains 13.6% bit-rate reduction over the HM-1.0.