• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12A
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• pp.2012-2018
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• 2001

This paper proposes the adaptive suboptimal iterative algorithm using threshold to reduce system complexity in the PTS\`s. Performance of the proposed adaptive suboptimal iteration algorithm is represented in terms of iteration number and CDF. In the case of the number of sub-block is 4, the 10-3 PAPR of the proposed method and P S improved this by 0.4dB compared to Cimini\`s. And the complexity of the proposed method was reduced to nearly 22% for the PTS\`s and 44% for the Cimini\`s for 8dB threshold. For the 8 sub-blocks, the 10$\^$-3/ PAPR of the proposed method reduced by 0.7dB compared to PTS\`s, but improved by 0.4dB compared to Cimini\`s. And the complexity of the proposed method was reduced to nearly 2.4% for the PTS\`s and 39% for the Cimini\`s.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.355-361
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• 2014

In this paper, we propose a complexity reduction method of sample adaptive offset (SAO), which is an in-loop filter in high-efficiency video coding (HEVC). In the conventional SAO, an offset value is calculated for each coding tree block (CTB) to minimize the error between the original and reconstructed images. In order to determine the optimal offset value, all offset candidates are examined and the offset value that leads to the smallest rate-distortion cost is chosen. Thus, SAO occupies a significant amount of the computational complexity in the HEVC encoder. In the proposed method, we determine the least-used band (LUB) by considering the statistical characteristics of offset values and without processing the offset value included in the LUB. Also, in the offset value decision stage, we check only a certain number of candidates rather than all of them. Experimental results show that the proposed method reduces the encoding time by approximately 8.15% without yielding a significant loss in terms of coding efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1165-1171
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• 2010

The OFDM system has better characteristics in transmission rate, power efficiency, bandwidth efficiency, impulse-noise immunity, and narrow band interference immunity etc. in comparison with other conventional systems. However, high PAPR of an OFDM signals causes some serious non-linear processing of RF amplifier. And performance of the communication system gets worse. Therefore, various methods reducing PAPR of an OFDM skills such as the clipping method, block coding method, and phase rotation method etc. have been researched. In this paper, we propose a high-speed adaptive PTS method which eliminates high PAPR. And we compare the proposed method with other conventional methods. The proposed method has decreased quantity of calculation compare with an adaptive PTS method. Of course, The more its calculation amount is decreased, the more its BER characteristic is not better than an adaptive PTS method. However, keeping up satisfactory BER performance, we highly improved calculation amount of a PTS method.

• Journal of Broadcast Engineering
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• v.18 no.2
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• pp.167-177
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• 2013

In this paper, a motion adaptive deinterlacing algorithm is proposed. It consists of three parts: (1) modified edge-based line average, (2) pixel-based consequent five-field motion detection, and (3) block-based local characteristic for detecting true motion and calculating the motion intensity by using an improved method which is able to detect the inner part of moving objects precisely as well as to reduce the risk of false detection caused by intrinsic noises in the image. Depending on the detected motion activity level, it combines spatial and temporal methods with weighting factor. Simulations conducted on several video sequences indicate that the performance of the proposed method is superior to the conventional methods in terms of both subjective and objective video quality.

• Journal of Broadcast Engineering
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• v.20 no.4
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• pp.533-544
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• 2015

Recently, most of the video services are usually transmitted in wireless networks. In networks environment, a packet of video is likely to be lost during transmission. For this reason, this paper proposes a new Error Concealment (EC) algorithm. For High Efficiency Video Coding (HEVC) bitstreams, the proposed algorithm includes Adaptive Prediction Unit-based Motion Vector Extrapolation (APMVE) and Boundary Matching (BM) algorithm, which employs both the temporal and spatial correlation. APMVE adaptively decides a Error Concealment Basic Unit (ECBU) by using the PU information of the previous frame and BM employing the spatial correlation is applied to only unreliable blocks. Simulation results show that the proposed algorithm provides the higher subjective quality by reducing blocking artifacts which appear in other existing algorithms.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.2
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• pp.1-8
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• 2020

This study is intended to derive the adaptive reuse techniques through the history and aspects of new construction, extension, repair, and other works, limited to the deep and narrow lots facing Seongan-gil and Nammun-gil in Nammun-ro 2 ga of Cheongju, the historic urban area. The results are as follows. 1) In the case of newly built reinforced concrete buildings, the central part of the top floor of the residence or all floors are opened to the open space(void) to facilitate lighting and ventilation. This is developed as a convection phenomenon due to the temperature difference from the slits between buildings, which affects the entire air flow of the block. 2) The buildings of extension and repair are composed of two-story masonry or steel frame, both the front store facing the road and the house on the back, but it looks like one because it is in contact with each other. If only a small gap between the front and rear buildings is restored to an external space or a space equipped with sun light, a small breath can be provided in lighting and ventilation. 3) The existing two-story wooden stores and houses have lost their external space due to repairs. With minimal intervention to restore the small courtyard, slits, and space under the eaves, it will not only improve lighting and ventilation, but also create a unique appearance as a segment of the elongated store.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.7 s.361
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• pp.45-53
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• 2007

In this paper, we propose an efficient hardware architecture for H.264/AVC CAVLC (Context-based Adaptive Variable Length Coding) encoding. Previous CAVLC architectures search all of the coefficients to find statistic characteristics in a block. However, it is unnecessary information that zero coefficients following the last position of a non-zero coefficient when CAVLC encodes residual coefficients. In order to reduce this unnecessary operation, we propose two techniques, which detect the first and last position of non-zero coefficients and arrange non-zero coefficients sequentially. By adopting these two techniques, the required processing time was reduced about 23% compared with previous architecture. It was designed in a hardware description language and total logic gate count is 16.3k using 0.18um standard cell library Simulation results show that our design is capable of real-time processing for $1920{\times}1088\;30fps$ videos at 81MHz.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.31-37
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• 2018

This paper proposes an effective single-image haze-removal algorithm with low complexity by using a dual dark channel prior (DCP) and an adaptive brightness correction technique. The dark channel of a small patch preserves the edge information of the image, but is sensitive to noise and local brightness variations. On the other hand, the dark channel of a large patch is advantageous in estimation of the exact haze value, but halo effects from block effects deteriorate haze-removal performance. In order to solve this problem, the proposed algorithm builds a dual DCP as a combination of dark channels from patches with different sizes, and this meets low-memory and low-complexity requirements, while the conventional method uses a matting technique, which requires a large amount of memory and heavy computations. Moreover, an adaptive brightness correction technique that is applied to the recovered image preserves the objects in the image more clearly. Experimental results for various hazy images demonstrate that the proposed algorithm removes haze effectively, while requiring much fewer computations and less memory than conventional methods.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12C
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• pp.1225-1238
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• 2003

We present an efficient algorithm for skew correction of business card images obtained by a PDA (personal digital assistant) camera. The proposed method is composed of four parts: block adaptive binarization (BAB), stripe generation, skew angle calculation, and image rotation. In the BAB, an input image is binarized block by block so as to lessen the effect of irregular illumination and shadow over the input image. In the stripe generation, character string clusters are generated merging adjacent characters and their strings, and then only clusters useful for skew angle calculation are output as stripes. In the skew angle calculation, the direction angles of the stripes are calculated using their central moments and then the skew angle of the input image is determined averaging the direction angles. In the image rotation, the input image is rotated by the skew angle. Experimental results shows that the proposed method yields skew correction rates of about 93% for test images of several types of business cards acquired by a PDA under various surrounding conditions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4C
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• pp.253-261
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• 2005

In this paper, we propose an efficient block-based disparity estimation algorithm fur multiple view image coding in EE2 and EE3 in 3DAV. The proposed method emphasizes on visual quality improvement to satisfy the requirements for multiple view generation. Therefore, we perform an adaptive disparity estimation that constructs variable blocks by considering given image features. Examining neighboring features around desired block search range is set up to decrease complexity and additional information than only using quad-tree coding through applying binary-tree and quad-tree coding by taking into account stereo image feature having big disparity. The experimental results show that the proposed method improves PSNR about 1 to 2dB compared to existing other methods and decreases computational complexity up to maximum 68 percentages than FBMA.