检索结果-内蒙古大学图书馆

Proposal of an experimental data and image transmission system and its possible application for remote monitoring smart grids

引用

Journal of Applied Research and Technology 2017年第3期15卷 303-310页

作者： Develi, Ibrahim Kabalci, Yasin Department of Electrical & Electronics Engineering Faculty of Engineering Erciyes University Kayseri 38039 Turkey Department of Electronics and Automation Nigde Vocational College of Technical Sciences Nigde University Nigde 51200 Turkey

This paper investigates the bit error rate (BER) and the peak signal-to-noise ratio (PSNR) performances of quasi-cyclic low-density parity-check (QC-LDPC) coded orthogonal frequency-division multiplexing (OFDM) systems over an actual power line communication (PLC) channel that are acquired by performing very long-term experimental measurements from the grid. The examined system is tested by changing system parameters such as code length, iteration number, coding rate and message type in detail. The results of this study show that the QC-LDPC coded OFDM system can be a possible solution for communication and remote monitoring purposes in smart grids. © 2017 Universidad Nacional Autónoma de México, Centro de Ciencias Aplicadas y Desarrollo Tecnológico

关键词： Orthogonal frequency-division multiplexing (OFDM) Power line communication (PLC) Quasi-cyclic low-density parity-check (QC-LDPC) codes Remote monitoring Smart grids

来源：评论

学校读者我要写书评

暂无评论

Concatenated Block Codes for Unequal Error Protection of Embedded bit Streams

引用

ieeE TRANSACTIONS ON image PROCESSING 2012年第3期21卷 1111-1122页

作者： Arslan, Suayb S. Cosman, Pamela C. Milstein, Laurence B. Univ Calif San Diego Dept Elect & Comp Engn La Jolla CA 92093 USA

A state-of-the-art progressive source encoder is combined with a concatenated block coding mechanism to produce a robust source transmission system for embedded bit streams. The proposed scheme efficiently trades off the available total bit budget between information bits and parity bits through efficient information block size adjustment, concatenated block coding, and random block interleavers. The objective is to create embedded codewords such that, for a particular information block, the necessary protection is obtained via multiple channel encodings, contrary to the conventional methods that use a single code rate per information block. This way, a more flexible protection scheme is obtained. The information block size and concatenated coding rates are judiciously chosen to maximize system performance, subject to a total bit budget. The set of codes is usually created by puncturing a low-rate mother code so that a single encoder-decoder pair is used. The proposed scheme is shown to effectively enlarge this code set by providing more protection levels than is possible using the code rate set directly. At the expense of complexity, average system performance is shown to be significantly better than that of several known comparison systems, particularly at higher channel bit error rates.

关键词： Concatenated block coding embedded bit streams fine-grain scalability H.264 joint source-channel coding (JSCC) JPEG2000 packetization rate allocation set partitioning in hierarchical trees (SPIHT) unequal error protection (UEP)

来源：评论

学校读者我要写书评

暂无评论

Enhanced Renormalization Algorithm in MQ-Coder of JPEG2000

Enhanced Renormalization Algorithm in MQ-Coder of JPEG2000

引用

International Symposium on Information Technology Convergence (ISITC)

作者： Byungjun Min Sook Yoon Jungjin Ra Dong Sun Park Division of Electronics & Information Engineering college of Engineering Chonbuk National University of Korea South Korea Major in Multimedia Engineering School of Inform. Engineering College of Engineering Mokpo National University South Korea

JPEG2000 is the latest still-image coding standard. It was designed to overcome the limitation of the original JPEG standard and provide high quality images at low bit rates. The JPEG2000 algorithm is fundamentally based on the discrete wavelet transform (DWT) and embedded block coding with optimal truncation (EBCOT). Both algorithms are computation- and memory- intensive. JPEG2000 uses an adapted version of Q-coder, called MQ-coder. Pervious researches mainly focused on speeding up the DWT and BPC other than renormalization part of MQ-coder. Renormalization procedure in MQ-coder contributes to the computation in relatively high percentage. In this paper, we propose an enhanced renormalization algorithm for arithmetic coding in EBCOT tier-1 coding procedure. By analyzing and simplifying the existing algorithm, the proposed algorithm can reduce the computation with a significant percentage. Experimental results show that the computation is reduced approximately 25% comparing to the renormalization procedure of the regular arithmetic coding.

关键词： image coding Transform coding Discrete wavelet transforms Arithmetic Block codes Algorithm design and analysis Educational institutions bit rate Computational complexity Wavelet coefficients

来源：评论

学校读者我要写书评

暂无评论

low complexity deblocking method for DCT coded video signals

引用

iee PROCEEDINGS-VISION image AND SIGNAL PROCESSING 2006年第1期153卷 46-56页

作者： Tai, SC Chen, YR Chen, CY Chen, YH Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan Natl Cheng Kung Univ Inst Comp & Commun Tainan 70101 Taiwan

A new method to remove blocking artefacts in low bit-rate block-based video coding, such as MPEG-4 and H.264, is presented. A low computational deblocking filter with five modes is proposed, including three frequency-related modes (smooth mode, intermediate mode, and complex mode for low-frequency, mid-frequency, and high-frequency regions, respectively), one special mode (steep mode for a large offset between two blocks) and a refined mode (corner mode for the corner of four blocks). A mode decision procedure is also needed to decide which mode is given by observing pixel behaviour around the block boundary. To take the masking effect of the human visual system (HVS) into consideration, the filter for smooth mode is designed to be much stronger than that for complex mode, because human eyes are more sensitive to smooth regions. Experimental results show that, in most cases, the proposed algorithm removes more blocking artefacts than MPEG-4 deblocking filters do, and improves both subjective and objective image quality. The proposed algorithm keeps the computation lower than MPEG-4 and is suitable for most block-based image and video coding systems.

关键词： SIGNAL processing image processing SIGNAL processing -- Digital techniques DIGITAL image processing MPEG (Video coding standard) DIGITAL video -- Standards VIDEO compression -- Standards VIDEO equipment DIGITAL electronics

来源：评论

学校读者我要写书评

暂无评论

Hybrid deblocking algorithm for block-based low bit rate coded images

引用

6th Pacific Rim Conference on Multimedia - Advances in Mulitmedia Information Processing - PCM 2005

作者： Kwon, Kee-Koo Jeon, In-Su Lim, Dong-Sun Embedded S/W Research Division ETRI 161 Gajeong-dong Yuseong-gu Daejeon 305-350 Korea Republic of Telecommunication Network Business Samsung Electronics Co. Ltd. Gongdan 2-dong Gumi-si Gyeongsangbuk-do 730-736 Korea Republic of

ISBN: (纸本)3540300279

In this paper, we propose a hybrid deblocking algorithm to improve the visual quality of block-based low bit rate coded images, those are processed both spatial and wavelet domains. The proposed algorithm reduces the blocking artifacts using the statistical characteristics of block discontinuity as well as the lipschitz regularity along the behavior of wavelet coefficients across scales. In this algorithm, detection of blocking artifacts and block boundary classification is performed in spatial domain to reduce the computational complexity for performing the wavelet transform and inverse wavelet transform for all image, and adaptive filtering is processed in spatial or wavelet domains. Spatial adaptive filtering is processed to reduce the blocking artifacts in smooth region with the blocking artifacts. For complex or mixed region, the Lipschitz regularity is obtained to analyze the evolution of the local maxima of the wavelet transform modulus across scales and these irregular singularities are adaptively removed in wavelet domain. Experimental results show that the proposed algorithm produced better results than those of conventional algorithms both PSNR and visual quality. © Springer-Verlag Berlin Heidelberg 2005.

关键词： image coding

来源：评论

学校读者我要写书评

暂无评论

Content adaptive image de-blocking

Content adaptive image de-blocking

引用

ieeE International Symposium on Consumer electronics

作者： Zhao, M Kneepkens, REJ Hofman, PM de Haan, G Eindhoven Univ Technol Informat & Commun Grp NL-5600 MB Eindhoven Netherlands

ISBN: (纸本)0780385268

Blocking artifacts may appear in block based digital image and video coding systems like JPEG and MPEG, especially when compression is done at a low bit-rate. The blocking artifacts can degrade the perceived image quality. In this paper, a method for reducing the blocking artifacts in the decoded image using adaptive filters is proposed The selection of the proper filter is based on the local image pattern and/or the relative pixel position in the coding block. The results show a significant image quality improvement. To evaluate the methods, both Mean Square Error (MSE) scores and Block-edge Impairment Metric (BIM) are given for objective comparison. Screen shots are also shown to demonstrate the subjective quality.

关键词： content adaptive filtering de-blocking JPEG MPEG

来源：评论

学校读者我要写书评

暂无评论

A rate-control scheme using fast frame-rate controlling and adaptive rate-quantization modeling for H.263

A rate-control scheme using fast frame-rate controlling and ...

引用

2004 ieeE International Symposium on Consumer electronics - Proceedings

作者： Chan, Din-Yuan Chang, Chun-Yuan Lin, Shou-Jen Lin, Chung-Wei Dept. of Computer Science National Chiayi University Chiayi City Taiwan Dept. of Information Engineering I-Shou University Kaohsiung Country Taiwan

ISBN: (纸本)0780385276

bit-rate control plays a critical role in the video-coding. One of the main challenges of video-coding is to provide the guaranteed quality under highly compressed video. In our study, a structured R-Q base rate-control framework is proposed for low-delay video coding, which contains three processing stages: the control of encoding frame-rate, bit-allocation for frame-level and the decision of quantization parameters for macroblock-level. First, the proposed framework decides the encoding frame-rate per group of pictures (GOPs) for better motion continuity. In the second stage, target-bit per frame is effectively estimated with the frame texture and buffer fullness. Last, based on an adaptive R-Q model modified by the Kalman filter for each cluster of MBs (COBs), a suitable quantization parameter of each MB can be confirmed. In comparison with the TMN8rc module, our new framework can achieve higher objective and perceptual quality with lower computational complexity.

关键词： image coding

来源：评论

学校读者我要写书评

暂无评论

Field experiments on low-rate Tturbo coding and soft-decision decoding for broadband packet DS-CDMA wireless access in reverse link

Field experiments on low-rate Tturbo coding and soft-decisio...

引用

2004 ieeE 15th International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2004

作者： Suwa, Shingo Miki, Nobuhiko Tanno, Motohiro Higuchi, Kenichi Sawahashi, Mamoru IP Radio Netwk. Devmt. Department NTT DoCoMo Inc. 3-5 Hikari-no-oka Yokosuka-shi Kanagawa-ken 239-8536 Japan

This paper investigates the practical effects of low-rate Turbo coding and its soft-decision decoding considering the influence of path timing detection, channel estimation, and pre-decoder level adjustment for broadband packet DS-CDMA in the reverse link in a real multipath Rayleigh fading channel. Field experiments are conducted in an urban environment using the implemented broadband DS-CDMA transceiver at the average vehicular speed of approximately 30 km/h. The experimental results elucidate that accurate path timing detection and channel estimation of each packet frame are achieved by taking advantage of the dedicated pilot channel for the use of low-rate Turbo coding (i.e., actual spreading factor value of data channel is nearly one). We clarify that by employing Turbo coding with the coding rate of R = 1/8, the required average received signal energy per bit-to-interference plus background noise power spectrum density ratio (Eb/I0) at the average packet error rate (PER) of 10-2 is decreased by approximately 1.0 to 1.5 dB compared to that with R = 1/2. Furthermore, we show that the additional improvements by reducing R to 1/16 are small assuming the same chip rate and employing two-branch antenna diversity reception associated with coherent Rake combining for broadband DS-CDMA with a 40-MHz bandwidth.

关键词： Code division multiple access

来源：评论

学校读者我要写书评

暂无评论

Geometrically determining leaky bucket parameters for video streaming over constant bit-rate channels

Geometrically determining leaky bucket parameters for video ...

引用

Proceedings - ieeE International Conference on Acoustics, Speech, and Signal Processing

作者： Li, Ping Lin, W.S. Rahardja, S. Lin, X. Yang, X.K. Li, Z.G. Media Division Institute for Infocomm Resarch 21 Heng Mui Keng Terrace Singapore 119613

For streaming of pre-encoded bitstreams over constant bit rate (CBR) channels, the channel bandwidth, the receiver buffer capacity as well as the latency requirement vary greatly from application to application. In this paper, we propose an algorithm to determine the minimum buffer size and the minimum start-up delay required for streaming a pre-encoded bitstream over CBR channels at any specific bit rate. The proposed method employs geometric operations to derive the optimal determination for low or high bit rates and sub-optimal determination for medium bit rates. The results have been compared with the H.264/AVC hypothetical reference decoder. The proposed approach provides a theoretical insight and a simple but effective algorithm for determining the leaky bucket parameters for video streaming over CBR channels.

关键词： image coding

来源：评论

学校读者我要写书评

暂无评论

High performance video compression based on improved VSPIHT algorithm

High performance video compression based on improved VSPIHT ...

引用

2004 7th International Conference on Signal Processing Proceedings (ICSP'04)

作者： Jia, Hu Wengqi, Ding Liming, Zhang Dept. of Electronics Engineering Fudan University Shanghai 200433 China

This paper proposes an effective I3D-DWT-VSPIHT video coding method, which reasonably organizes wavelet coefficients by integrated 2D-SPIHT with 3D-VSPIHT, and the video sequence is partitioned into two alternate parts: original frames and residual frames, so the similar coefficients can be compressed to one or fewer symbols by sufficiently using correlation between trees, and the reconstructive image quality as well as memory saving can be improved. On the other hand, by effectively reducing redundant scan time it is available in real-time system. Simulated results show that the quality (PSNR) of reconstructed video at the same compression ratio is improved about 1 ∼ 5dB for gray video as compared with existent 3D-DWT-SPIHT. By using the high performance video compression method, available for gray and color video sequences, very low bit rate and high quality of reconstructed image can be obtained.

关键词： image compression

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：