• Journal of electromagnetic engineering and science
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• v.6 no.4
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• pp.244-252
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• 2006

A block Jacket transform and. its block inverse Jacket transformn have recently been reported in the paper 'Fast block inverse Jacket transform'. But the multiplication of the block Jacket transform and the corresponding block inverse Jacket transform is not equal to the identity transform, which does not conform to the mathematical rule. In this paper, new binary block Jacket transforms and the corresponding binary block inverse Jacket transforms of orders $N=2^k,\;3^k\;and\;5^k$ for integer values k are proposed and the mathematical proofs are also presented. With the aid of the Kronecker product of the lower order Jacket matrix and the identity matrix, the fast algorithms for realizing these transforms are obtained. Due to the simple inverse, fast algorithm and prime based $P^k$ order of proposed binary block inverse Jacket transform, it can be applied in communications such as space time block code design, signal processing, LDPC coding and information theory. Application of circular permutation matrix(CPM) binary low density quasi block Jacket matrix is also introduced in this paper which is useful in coding theory.

• Journal of Broadcast Engineering
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• v.3 no.2
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• pp.111-117
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• 1998

Due to independent processing of image block, DCT-based block coding algorithms can produce the blocking effect qhich is gray-level discontinuity along block boundaries of the reconstructed image. In this paper, we have proposed two techniques to reduce the blocking effect: two-stage transform coding with variable quantizer and the globally optimum filtering. We have also compared performances of our algorithms and other conventional algorithms by applying optimal allocation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.8
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• pp.1707-1714
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• 1997

This paper proposes a novel algorithm for fractal coding of image sequence, based on the CPM (Circular Prediction Mapping) and the NCIM (Non Contractive Interframe Mapping). In the CPM and the NCIM, each range block is approximated by a domain block in the adjacent frame, which is of the same size as the range block. Also, in this paepr, we propose a coding scheme of color components and an algorithm for controlling the bit rate, resepectively, for practical implementation of the fractal coder. The computer simulation results on real image sequences demonstrate that the proposed algorithm provides very promising performance at low bit-rate, below 256 Kbps.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.601-604
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• 1999

We propose a new hierarchical motion estimator architecture that supports the advanced prediction mode of recent low bit-rate video coders such as H.263 and MPEG-4. In the proposed VLSI architecture, a basic searching unit (BSU) is commonly utilized for all hierarchical levels to make a systematic and small sized motion estimator. Since the memory bank of the proposed architecture provides scheduled data flow for calculating 8$\times$8 block-based sum of absolute difference (SAD), both a macroblock-based motion vector (MV) and four block-based MVs are simultaneously obtained for each macroblock in the advanced prediction mode. The proposed motion estimator gives similar coding performance compared with full search block matching algorithm (FSBMA) while achieving small size and satisfying the advanced prediction mode.

• Journal of Broadcast Engineering
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• v.15 no.5
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• pp.672-680
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• 2010

This paper presents an adaptive quantization matrix selection scheme for H.264 video encoding. Conventional H.264 coding standard applies the same quantization matrix to the entire video sequence without considering local characteristics in each frame. In this paper, we propose block adaptive selection of quantization matrix according to edge directivity of each block. Firstly, edge directivity of each block is determined using intra prediction modes of its spatially adjacent blocks. If the block is decided as a directional block, new weighted quantization matrix is applied to the block. Otherwise, conventional quantization matrix is used for quantization of the non-directional block. Since the proposed weighted quantization is designed based on statistical distribution of transform coefficients in accordance with intra prediction modes, we can achieve high coding efficiency. Experimental results show that the proposed scheme can improve coding efficiency by about 2% in terms of BD bit-rate.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.231-236
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• 2015

In this paper, the technical analysis and characteristics of screen content coding (SCC) based on High efficiency video coding (HEVC) are presented. For SCC, which is increasingly used these days, HEVC SCC standardization has been proceeded. Technologies such as intra block copy (IBC), palette coding, and adaptive color transform are developed and adopted to the HEVC SCC standard. This paper examines IBC and palette coding that significantly impacts RD performance of SCC for screen content. The HEVC SCC reference model (SCM) 4.0 was used to comparatively analyze the coding performance of HEVC SCC based on the HEVC range extension (RExt) model for screen content.

• Journal of Creative Information Culture
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• v.5 no.3
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• pp.307-317
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• 2019

This study is an example of the education of block coding and physical computing teaching tool for preservice teachers at the college of education. The students were familiar with coding and improved their coding skills in solving various problems through 'Entry' that support block coding. In addition, the students configured the computing system with various input / output devices of the physical computing teaching tool and controlled things through programming and produced the educational portfolio to experience the whole process of problem analysis, design, implementation, and testing in coding. We applied Flow based coding and Pair programming as the teaching methods, and the results of the survey to measure the effectiveness of the study show that students have a good understanding of the entry and physical computing teaching tool and using the combination of the entry and physical computing teaching tool were more effective in learning than the Entry-only coding. In addition, it was confirmed that the effect of Pair programming applied in the physical computing teaching tool.

• Journal of Digital Contents Society
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• v.18 no.1
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• pp.63-70
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• 2017

Recently, as user feedback such as social reading become active, demand has been increased on e-book contents making which is based on user feedback. However, to reflect the user feedback onto the e-book, direct coding is required, which was difficult to the author who was not good at programming. To resolve this problem, Block assembly style feedback editor system, using Blockly was developed. This editor enables to reflect the user feedback by area allocation, component allocation, block editing, and code generating insertion, contrary to the existing way of programming realization in which direct coding was required for input, processing and output separately. This system was developed by using HTML. Javascript, PHP, and Codeigniter. Block editing is enabled to do provision and assembly of blocks by Blockly. The function of code generation & insertion allows to insert the Library function code. Through this system, the general users who are not capable of coding also can reflect feedback without doing actual coding.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2351-2354
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• 2003

A new transform coder for arbitrarily shaped image segments is proposed. In the encoder, a block-based DCT is applied to the resulting image block after shifting pixels within the image segment to block border and padding the mean value of the pixels to empty region. For reducing the transmission bit rate, the transform coefficients located in padded region are truncated and only the remaining transform coefficients are transmitted to the decoder. In the decoder, the transform coefficients truncated in the encoder are recovered using received transform coefficients and a block-based inverse DCT is performed.

• Journal of Broadcast Engineering
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• v.25 no.6
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• pp.911-921
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• 2020

Recently, MPEG-I (Immersive) has been exploring compression performance through standardization projects for immersive video. The MPEG Immersion Video (MIV) standard technology is intended to provide limited 6DoF based on depth map-based image rendering (DIBR). MIV is a model that processes the Basic View and the residual information into an Additional View, which is a collection of patches. Atlases have the unique characteristics depending on the kind of the view they are included, requiring consideration of the compression efficiency. In this paper, the performance comparison analysis of screen content coding tools such as intra block copy (IBC) is conducted, based on the pattern of various views and patches repetition. It is demonstrated that the proposed method improves coding performance around -15.74% BD-rate reduction in the MIV.