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fractal Depth Map Sequence coding Algorithm with Motion-vector-field-based Motion Estimation

KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS 2015年第1期9卷 242-259页

作者： Zhu, Shiping Zhao, Dongyu Beihang Univ Sch Instrumentat Sci & Optoelect Engn Dept Measurement Control & Informat Technol Beijing 100191 Peoples R China

Three-dimensional video coding is one of the main challenges restricting the widespread applications of 3D video and free viewpoint video. In this paper, a novel fractal coding algorithm with motion-vector-field-based motion estimation for depth map sequence is proposed. We firstly add pre-search restriction to rule the improper domain blocks out of the matching search process so that the number of blocks involved in the search process can be restricted to a smaller size. Some improvements for motion estimation including initial search point prediction, threshold transition condition and early termination condition are made based on the feature of fractal coding. The motion-vector-field-based adaptive hexagon search algorithm on the basis of center-biased distribution characteristics of depth motion vector is proposed to accelerate the search. Experimental results show that the proposed algorithm can reach optimum levels of quality and save the coding time. The PSNR of synthesized view is increased by 0.56 dB with 36.97% bit rate decrease on average compared with H.264 Full Search. And the depth encoding time is saved by up to 66.47%. Moreover, the proposed fractal depth map sequence codec outperforms the recent alternative codecs by improving the H.264/AVC, especially in much bitrate saving and encoding time reduction.

关键词： fractal coding depth map coding 3D video motion estimation Hexagon Search

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CONCEPT RETRIEVAL BASED ON A COMBINATION OF fractal coding, FUZZY RULE BASED SYSTEM AND SVM

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fractalS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY 2011年第2期19卷 185-194页

作者： Lotfi, Ehsan Yaghoobi, Mahdi Islamic Azad Univ Dept Comp Engn Mashhad Branch Mashhad Iran

Most information retrieval systems make indirect use of human knowledge in their retrieval process. The new method we present here aims to efficiently use human knowledge directly in combination with fractal coding and support vector machine (SVM) for clustering. As illustrated in this paper, this approach is particularly applicable to soccer concept retrieval from video databases. The first phase consists of extracting suitable features and key frames from video shots. Then, using a fractal coding, soccer shots are retrieved, and using a fuzzy rule base containing the experiences of experts, shots that do not include significant soccer events are removed. Finally, the last phase uses SVM to classify results coming from the fuzzy system. The results of the classification phase are accompanied by a textual description and enables retrieval through text based query. Experimental results show proper classification and satisfying retrieval process.

关键词： Concept Retrieval Fuzzy System SVM fractal coding Soccer Video

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An Effective chaos-based image watermarking scheme using fractal coding

An Effective chaos-based image watermarking scheme using fra...

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1st World Conference on Information Technology (WCIT)

作者： Keyvanpour, MohammadReza Merrikh-Bayat, Farnoosh Alzahra Univ Dept Comp Engn Tehran Iran Islamic Azad Univ Dept Comp Engn Qazvin Iran

The image watermarking technology is a technique of embedding hidden data in an original image. In this paper, a new watermarking method for embedding watermark bits based on Chaos-fractal coding is given. A chaotic signal is defined as being deterministic, pseudo periodic and presenting sensitivity to initial conditions. Combining a chaos system with fractal coding plays an important role in the security, invisibility and capacity of the proposed scheme. The main idea of the new proposed algorithm for coding is to determine a set of selective blocks for steady embedding. Simulation results show that the CFC algorithm (Chaos-fractal coding) has a confident capacity. The embedding technique that proposed in this paper is quite general, and can be applied to the extracting scheme with demanded changes. (C) 2010 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the Guest Editor.

关键词： Image Watermarking fractal coding Chaos Cryptography Arnold's Cat Map Capacity

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An Effective chaos-based image watermarking scheme using fractal coding

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Procedia Computer Science 2011年 3卷 89-95页

作者： MohammadReza Keyvanpour Farnoosh Merrikh-Bayat Department of Computer Engineering Alzahra University Tehran Iran Department of Computer Engineering Islamic Azad Uviversity Qazvin Branch Qazvin Iran

关键词： Image watermarking fractal coding Chaos cryptography Arnold’s cat map Capacity

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A Review on Audio Steganography Techniques

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Research Journal of Applied Sciences, Engineering and Technology 2016年第2期12卷 154-162页

作者： Ahmed Hussain Ali MohdRosmadiMokhtar LoayEdwar George Department of Computer Science College of Science University of Baghdad Baghdad Iraq

The aim of this study is to present different types of steganography in brief and to give a special attention to audio steganography technique because a huge number of audio files are exchanged through the networks. Nowadays the widening of attacker’s abilities to access the private and public information transmitted over public communication system makes way for highlighting a tool that guarantees the secure transmission of hidden information. Information hiding was a common security term that mainly includes three techniques: cryptography, steganography and watermark. Cryptography was an ancient form that is used for confidential data. Steganography is a popular tool that uses digital medium to hide confidential data in innocent carrier such as image, audio, text and video. Steganography is in fact a complement for the earlier data hiding technique cryptography. However watermark is used for copyright protection. Audio steganography is technique that hides any type of secret data in cover audio file. This study also discusses the main requirements of steganography methods and how those methods achieve them. Furthermore it shows steganography domain and, carriers and information hiding techniques used in audio.

关键词： Carrier cryptography fractal coding LSB steganography requirements vector quantization wavelet transform

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An Effective Image Retrieval Method Based on fractal Dimension Using Kernel Density Estimation 1

An Effective Image Retrieval Method Based on Fractal Dimensi...

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1st International Conference on Communication and Computer Engineering (ICOCOE)

作者： Zhang Qin Huang Xiaoqing Liu Wenbo Nanjing Univ Aeronaut & Astronaut Coll Automat Engn Nanjing Jiangsu Peoples R China

ISBN: (纸本)9783319076744;9783319076737

fractal coding has been proved useful for image compression, and it is also proved effective for image retrieval. In the paper, we present a statistical method called variable bandwidth kernel density estimation to analyze fractal coding parameters. Then retrieve images using the retrieval index constructed with this method. Experimental results show that the proposed method with a variable optimized bandwidth performs better than those with a fixed bandwidth and the histogram method both in retrieval rate and retrieval speed. In this paper, the Average Retrieval Rate (ARR) can reach 72.40 %, which is more than that obtained by the existing methods.

关键词： fractal coding Kernel density estimation Variable optimized bandwidth Image retrieval

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Object-based stereo video compression using fractals and shape-adaptive DCT

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2014年第7期68卷 687-697页

作者： Belloulata, Kamel Belalia, Amina Zhu, Shiping Univ Djillali Liabes Sidi Bel Abbes Fac Engn Dept Elect Sidi Bel Abbes Algeria BeiHang Univ Sch Instrumentat Sci & Optoelect Engn Dept Measurement Control & Informat Technol Beijing 100083 Peoples R China

Based on the classical fractal video compression method, an improved object-based stereo video compression scheme with Shape-Adaptive DCT is proposed in this paper. Firstly, we use more effective macroblock partition scheme instead of classical quadtree partition scheme;thus reducing the block searching strategy. The stereo fractal video coding is proposed which matches the macroblock with two reference frames in left and right view results in increasing compression ratio and reducing bit rate when transmitting compressed stereo data. The stereo codec combines the Motion Compensation Prediction (MCP) and Disparity Compensation Prediction (DCP). fractal coding is adopted and each object is encoded independently by a prior video segmentation alpha plane, which is defined exactly as in MPEG-4. The testing results with the nature monocular and stereo video sequences provide promising performances at low bit rate coding. We believe it will be a powerful and efficient technique for the object-based monocular and stereo video sequences coding. (C) 2014 Elsevier GmbH. All rights reserved.

关键词： Stereo video coding fractal coding Region-based coding SA-DCT MPEG-4

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Hybrid fractal-Wavelet Method for Multi-Channel EEG Signal Compression

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CIRCUITS SYSTEMS AND SIGNAL PROCESSING 2014年第8期33卷 2583-2604页

作者： Saeedi, Jamal Faez, Karim Moradi, Mohammad Hassan Amirkabir Univ Technol Dept Elect Engn Tehran Polytech Tehran Iran Amirkabir Univ Technol Dept Biomed Engn Tehran Polytech Tehran Iran

In this paper, a hybrid method is proposed for multi-channel electroencephalograms (EEG) signal compression. This new method takes advantage of two different compression techniques: fractal and wavelet-based coding. First, an effective decorrelation is performed through the principal component analysis of different channels to efficiently compress the multi-channel EEG data. Then, the decorrelated EEG signal is decomposed using wavelet packet transform (WPT). Finally, fractal encoding is applied to the low frequency coefficients of WPT, and a modified wavelet-based coding is used for coding the remaining high frequency coefficients. This new method provides improved compression results as compared to the wavelet and fractal compression methods.

关键词： Electroencephalograms Compression fractal coding Wavelet-based coding Multi-objective genetic optimization

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A novel initial image for fast fractal decoding 7

A novel initial image for fast fractal decoding

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7th International Congress on Image and Signal Processing (CISP)

作者： Yu Chaofan Southeast Univ Chien Shiung Wu Coll Nanjing Jiangsu Peoples R China

ISBN: (纸本)9781479958351

In order to speed up the fractal decoding, a novel initial image is proposed in this paper. In the case of the same decoding method, the convergence speed depends heavily on the similarity of the initial image with respect to the original image. With the development of the fractal coding, the matching errors between the range blocks and domain blocks become smaller and smaller. Thus, with the fractal code obtained in the fractal encoding process, we can reconstruct a novel initial image that can approximate the original image better. Experiments show that the initial image we propose can provide faster convergence speed than the conventional initial images.

关键词： fractal coding fast fractal decoding no search

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Wavelet Transformed based Fast fractal Image Compression

Wavelet Transformed based Fast Fractal Image Compression

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International Conference on Circuits, Systems, Communication and Information Technology Applications (CSCITA)

作者： Chaudhari, R. E. Dhok, S. B. St Francis Inst Technol Elect & Telecommun Engn Bombay Maharashtra India Visvesvaraya Natl Inst Technol Elect Engn Nagpur Maharashtra India

ISBN: (纸本)9781479924943

The main requirement of compression system in multimedia applications with large image size (more than or equal to 512x512 pixels) is high compression ratio with acceptable visual quality. fractal image coding is one of the alternatives for high compression rate but due to exhaustive encoding time, it has limited practical applications. In this paper, wavelet transform based fast fractal image coding is proposed. FFT based fractal image coding with variable quadtree partition is applied to the approximation subband and three detail subbands of the wavelet transformed image. Quadtree partitioned wavelet subtree is constructed after wavelet decomposition of fractal decoded approximation subband image. The self similarities existing in wavelet subtree are exploited by predicting the coefficients at finer scale from those at coarser scale using affine transformation. The proposed method improves the visual quality of the decoded image at very low bit rate and achieves average 92% reduction of coding time compared to the pure fast fractal image coding. Results also show that the JPEG based compressed image PSNR value reduced by 4-5 dB when the compression ratio around 60:1-70:1.

关键词： fractal coding Wavelet transform Image compression Quadtree partition

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