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IASTED International Conference on Internet and Multimedia Systems and Applications

作者： Balasubramaniyam, B Edirisinghe, EA Bez, HE Loughborough Univ Dept Comp Sci Res Sch Informat Holywell Pk Loughborough LE11 3TU Leics England

ISBN: (纸本)0889865647

fractal image compression techniques promise better compression capabilities as compared to the currently popular DCT and DWT based techniques. However the complexity of the encoding process makes it an unpopular choice in many application areas. On the other hand, traditionally, digital images have been captured, processed and displayed on rectangular (square) grids. Alternatively hexagonal grid pixel representations are able to provide more natural image capture and display capabilities due to its close correspondence with the human retina. In this paper we propose a fractal image coding scheme specifically designed to code images represented on a hexagonal grid. We show that the proposed scheme provides a better compression performance and an average, 30 fold improvement in speed, as compared to the application of traditional fractal image coding schemes to rectangular grid images.

关键词： fractal coding hexagonal grid images image compression digital cameras

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Research of Neighborhood Searching fractal Image coding Algorithm based on Ant Colony Optimization

Research of Neighborhood Searching Fractal Image Coding Algo...

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SAI Intelligent Systems Conference (IntelliSys)

作者： Lou, Li Li, Yong Northwestern Polytech Univ Sch Elect & Informat Xian 710072 Peoples R China

ISBN: (纸本)9781467376068

A kind of fractal improved coding algorithms based on Ant Colony Optimization and neighborhood search matching way is presented in this paper. The compression ratio of this algorithm is higher than that of Jacquin's as well as the coding speed is faster than that of Jacquin's on the premise of similar signal-to-noise ratio. Experimental results show that the compression ratio of this neighborhood searching fractal image coding algorithm based on ant colony optimization can reach to 14.33, the PSNR can reach to 29.7dB, encoding time decreases to 120s and decoding time is 28s.

关键词： Ant Colony Optimization fractal coding Neighborhood Range Block

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Structure-based fractal image coding

Structure-based fractal image coding

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Conference on Digital Compression Technologies and Systems for Video Communications

作者： Titkov, B Tikhotskij, A Myboroda, A Buley, H TELEVIS RES INST NIITST PETERSBURGRUSSIA

ISBN: (纸本)0819423564

An image coding scheme using partitioned iterated function systems (fractal codec) is presented. It extends the usual block-based algorithms with quadtree partitioning by splitting with arbitrarily shaped masks. Besides the general advantages of fractal coding such as very high compression and scalable decoding this gives provision for shape- adaptive coding. Furthermore the usage of orthogonal luminance transformations results in code suitable for browsing. The codec now uses up to 256 masks at each level of the quadtree partition (up to four levels) which may be applied twice. The mask set was experimentally optimized on a set of images. The high degree of flexibility is handled besides the usage of the known 'multidimensional nearest neighbor search' by an estimation of useful masks based on a block-structure analysis. fractal referencing to parts of the image already coded allows for additional reduction of data rate. Controlling takes into account the compression efficiency of the different types of approximation. The bit stream of the encoded image is structured, pre-encoded and selectivity entropy coded by arithmetic coding. Remaining blocking artifacts are concealed by a generally applicable method called bending, which is designed to avoid blurring by filtering.

关键词： image compression fractal coding block-boundary-artefact concealment

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Classification and feature vector techniques to improve fractal image coding

Classification and feature vector techniques to improve frac...

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Conference on Convergent Technologies for the Asia-Pacific Region (TENCON 2003)

作者： Loganathan, D Amudha, J Mehata, KM Amrita Inst Technol & Sci Coimbatore 641001 Tamil Nadu India

ISBN: (纸本)0780381629

fractal image compression receives much attention because of its desirable properties like resolution independence, fast decoding and very competitive rate-distortion curves. Despite the advances made in fractal image compression the long computing time in encoding phase still remain as main drawback of this technique as encoding step in computationally expensive. A large number of sequential searches through portions of the image are carried out to identify best matches for other image portions. So far, serveral methods have been proposed in order to speed-up fractal image coding. Here an attempt is made to analyze the speed-up techniques like classification and feature vector, which demonstrates the search through larger portions of the domain pool without increasing computation time. In this way both the image quality and compression ratio are improved at reduced computation time. Experimental results and analysis show that proposed method can speed up fractal image encoding process over conventional methods.

关键词： fractal coding feature vector image compression

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fractal Video coding Using Modified Three-step Search Algorithm for Block-matching Motion Estimation 1

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International Conference on Computational Vision and Robotics (ICCVR)

作者： Kamble, Shailesh D. Thakur, Nileshsingh V. Malik, Latesh G. Bajaj, Preeti R. Yeshwantrao Chavan Coll Engn Comp Sci & Engn Nagpur Maharashtra India Ram Meghe Coll Engn & Management Comp Sci & Engn Badnera Amravati Maharashtra India GH Raisoni Coll Engn Comp Sci & Engn Nagpur Maharashtra India GH Raisoni Coll Engn Nagpur Maharashtra India

ISBN: (数字)9788132221968

ISBN: (纸本)9788132221968;9788132221951

The major problem with fractal-based coding technique is that, it requires more computation at the encoding phase. Therefore, to reduce this computation, block-matching motion estimation algorithms are used. In this paper, we proposed a modified three-step search algorithm (MTSS) for block-matching motion estimation which consists of two cross-search patterns as a few initial step of search, and two cross-hexagon search patterns as a subsequent step of search that is used to search the center part of search window. Experimentations are carried out on standard video databases, i.e., football, flower, akiyo, coast guard, and traffic. The results of efficient three-step search and cross-hexagon search are compared with our proposed approach with respect to the parameters such as mean of absolute difference (MAD) and average search points per frame. Along with this our proposed approach, frame-based technique is used for fractal video coding evaluated on parameters such as compression ratio, PSNR, encoding time, and bit rate.

关键词： fractal coding Motion estimation MTSS Three-step search Cross-hexagon search MAD Video coding Compression ratio PSNR

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An Improved No-search fractal Image coding Method 7

An Improved No-search Fractal Image Coding Method

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

作者： Bi, Sheng Wang, Qiang Dalian Maritime Univ Coll Informat Sci & Technol Dalian Peoples R China

ISBN: (纸本)9781479958351

In order to improve the performance of no-search fractal coding further, a two order fitting surface is proposed to approximate the range blocks and domain blocks. In our research, a novel gray-level transform with a fitting surface is introduced. On one hand, the fitting surface we propose can approximate the range and domain blocks better than the previous fitting planes, this can lead to smaller collage errors between the range blocks and best matching domain blocks. On the other hand, since the introduced fitting surface can be also used for both the range blocks and domain blocks, many bits can be saved to improve the compression ratio. Moreover, the no-search and quadtree techniques are also adopted, so the proposed method can be completed in a short time. Experiments show that compared with the previous similar method, the proposed method can provide higher PSNR with the same Bpp, higher PSNR while maintaining the same encoding time.

关键词： fractal coding No-search Fitting surface

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Hybrid fractal image coding method

Hybrid fractal image coding method

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Conference on Visual Communications and Image Processing 96

作者： Zhang, ZB Zhu, YT Zhu, GX Cao, HQ Xue, DH HUAZHONG UNIV SCI & TECHNOL DEPT ELECTR & INFORMAT ENGNWUHAN 430074PEOPLES R CHINA

ISBN: (纸本)0819421030

In recent years, fractal image compression has been paid great attention because of its potential of high compression ratio. In the previously published encoding techniques, an image is usually partitioned into nonoverlapping blocks, and each block is encoded by a self-affirm mapping from a larger block. A high cost of the searching process is generally needed to encode a block. With the help of experiments, we discovered blocks do exist which cannot be well matched with any larger blocks under self-affirm transform. To encode these kinds of blocks with the present fractal encoding method may result in relatively low fidelity on these blocks. In this paper, we propose a hybrid fractal encoding method based on DCT and self- affirm transforms to improve local fidelity and encoding speed. The concept of short distance piecewise self-similarity (SDPS) is defined. Those blocks possessing SDPS are encoded with near-center self-affirm transform method. Other blocks are encoded with quasi-JPEG algorithm. Our method makes use of both the advantages of fractal coding technique, possessing the potential of high compression ratio, and the advantages of JPEG algorithm providing high fidelity at low or medium compression.

关键词： image compression image coding fractal image compression IFS fractal coding fractal attractor DCT

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Region-based fractal video coding

Region-based fractal video coding

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7th International Symposium on Instrumentation and Control Technology

作者： Zhu, Shiping Belloulata, Kamel Beihang Univ Dept Measurement Control & Informat Technol Sch Instrumentat Sci & Optoelect Engn Beijing 100083 Peoples R China Univ Djilali Liabes Sidi Bel Abbes Fac Sci Ingn Dept Elect Sidi Bel Abbes 22000 Algeria

ISBN: (纸本)9780819473622

A novel video sequence compression scheme is proposed in order to realize the efficient and economical transmission of video sequence, and also the region-based functionality of MPEG-4. The CPM and NCIM fractal coding scheme is applied on each region independently by a prior image segmentation map (alpha plane) which is exactly the same as defined in MPEG-4. The first n frames of video sequence are encoded as a "set" using the Circular Prediction Mapping (CPM) and encode the remaining frames using the Non Contractive Interframe Mapping (NCIM). The CPM and NCIM accomplish the motion estimation and compensation, which can exploit the high temporal correlations between the adjacent frames of video sequence. The experimental results with the monocular video sequences provide promising performances at low bit rate coding, such as the application in video conference. We believe the proposed fractal video codec will be a powerful and efficient technique for the region-based video sequence coding.

关键词： Monocular video coding fractal coding region-based coding low bit rate coding

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Hybrid method for face recognition based on fractal coding and singular value decomposition

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Dianzi Yu Xinxi Xuebao/Journal of Electronics and Information Technology 2005年第4期27卷 544-547页

作者： Cao, Lin Liu, Xiao-Jun Zou, Mou-Yan Institute of Electronics Chinese Academy of Sciences Beijing 100080 China

In this paper, a new face recognition method based on fractal coding is proposed. fractal singular value neighbor distance is brought forward based on fractal neighbor distance. fractal coding and local singular value decomposition are used to improve the recognition rate. The experimental results show that the method can keep a good robustness to the variation of illumination, pose and expression, compared with fractal neighbor distances. Furthermore, the method shows that the training time is short and recognition rate is high.

关键词： Face recognition fractal coding fractal singular value neighbor distance Local singular value decomposition

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fractal image coding with a multiscaling-domain

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 2004年第2期87卷 79-87页

作者： Furusawa, R Nakagawa, M Nagaoka Univ Technol Fac Engn Nagaoka Niigata 9402188 Japan

In order to improve the approximation capability of fractal coding, a fractal coding method using multiple domains is proposed in which an approximation is carried out by superposition of contracted images from multiple domain blocks. By combining the multidomain method with the multiscaling procedure of dividing blocks into regions and individually providing the scaling coefficients of brightness, a contraction transform with even better degrees of approximation is obtained and edge reconstruction is improved. As a result, excellent reconstructed images are obtained even for complicated images for which high reproducibility cannot be realized with the conventional fractal coding. Also, it is possible to reproduce contour regions containing edges. (C) 2003 Wiley Periodicals, Inc.

关键词： fractal coding image compression self-similarity multidomain multiscaling

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