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Research and application of digital watermarking for remote sensing image based on fractal coding
基于分形编码的遥感图像数字水印技术研究

CHEN Hui,GUO Ke,CHEN Ling,
陈辉
,郭科,陈聆

计算机应用研究 , 2007,
Abstract: Digital watermarking algorithm on fractal coding was developed using the direct to copyright protection of remote sensing image, and was blind. The watermarking was binary image that contained a large number of information.The robustness of the algorithm could be improved because Arnold scrambling was applied to binary image before the watermarking embeds. It is proved by test that the algorithm with good robustness can provide a effective method for the copyright protection of remote sensing images.
Secure Fractal Image Coding  [PDF]
Shiguo Lian
Computer Science , 2007,
Abstract: In recent work, various fractal image coding methods are reported, which adopt the self-similarity of images to compress the size of images. However, till now, no solutions for the security of fractal encoded images have been provided. In this paper, a secure fractal image coding scheme is proposed and evaluated, which encrypts some of the fractal parameters during fractal encoding, and thus, produces the encrypted and encoded image. The encrypted image can only be recovered by the correct key. To keep secure and efficient, only the suitable parameters are selected and encrypted through in-vestigating the properties of various fractal parameters, including parameter space, parameter distribu-tion and parameter sensitivity. The encryption process does not change the file format, keeps secure in perception, and costs little time or computational resources. These properties make it suitable for secure image encoding or transmission.
Watermarking method on fractal coding for image authentication
以图像认证为目的的分形编码数字水印算法

Huang Xiaoqing,Yu Shenglin,
黄晓晴
,于盛林

中国图象图形学报 , 2012,
Abstract: For image authentication, a fragile digital watermarking method is proposed. This method embeds watermarking into fractal transform, and embeds fractal coding parameters as watermark into the host image. It can not only locate altered areas, but also automatically recover the original image through extracting the fractal coding parameters. Experimental results show that the proposed method is capable of tamper localization, and effective for automatic recovery.
Trigonometric Approximation in Fractal Image Coding
M. Candik
Radioengineering , 2001,
Abstract: In this paper is presented a new approach in fractal image codingbased on trigonometric approximation. The least square approximationmethod is used for approximation of blocks in standard fractal imagecompression algorithm. In the paper is shown that it is possible to usealso trigonometric approximation for describing of blocks in fractalimage coding. This approximation was implemented and analyzed frompoint of view of quality of reconstructed images. The experimentalresults of this method were tested on static grayscale images.
Some Modifications of Fractal Image Coding
D. Levicky,M. Candik,R. Pundzak
Radioengineering , 1999,
Abstract: In this paper some modifications of fractal image coding are presented. Proposed methods are based on correlation coefficients computing as an alternative approach to searching of similarity between blocks. The convergence speed of decoding process is faster then convergence speed of standard method. The convergence process with modified start conditions of decoding process are analysed and verified on gray scale static images too.
Fractal Image Coding
分形图象编码

He Aijun,Ma Zhengming,
何爱军
,马争鸣

中国图象图形学报 , 1999,
Abstract: This is an overview on fractal image coding. On the base of collecting and reading related documents, we describe the current research status of fractal image coding and make a remark on its prospect.
Several Remarks on Fractal Image Block Coding
L. Dedera,J. Chmurny
Radioengineering , 1997,
Abstract: In this paper the dependence of PSNR on the size of both a codebook pool and range blocks is compared. The statistical properties of the values of transformation coefficients and distances between coded range blocks and optimal domain blocks in the fractal image block coding scheme are discussed.
Fractal coding based on image local fractal dimension
Conci, Aura;Aquino, Felipe R.;
Computational & Applied Mathematics , 2005,
Abstract: fractal codification of images is based on self-similar and self-affine sets. the codification process consists of construction of an operator which will represent the image to be encoded. if a complicated picture can be represented by an operator then it will be transmitted or stored very efficiently. clearly, this has many applications on data compression. the great disadvantage of the automatic form of fractal compression is its encoding time. most of the time spent in construction of such operator is due on finding the best match between parts of the image to be encoded. however, since the conception of automatic fractal image compression, researches on improvement of the compression time are widespread. this work aims to provide a new idea for decrease the encoding time: a classification of image parts based on their local fractal dimension. the idea is implemented on two steps. first, a preprocessing analysis of the image identify the complexity of each image block computing its dimension. then, only parts within the same range of complexity are used for testing the better self-affine pairs, reducing the compression time. the performance of this proposition, is compared with others fractal image compression methods. the points considered are image fidelity, encoding time and amount of compression on the image file.
Fractal coding based on image local fractal dimension  [cached]
Aura Conci,Felipe R. Aquino
Computational and Applied Mathematics , 2005,
Abstract: Fractal codification of images is based on self-similar and self-affine sets. The codification process consists of construction of an operator which will represent the image to be encoded. If a complicated picture can be represented by an operator then it will be transmitted or stored very efficiently. Clearly, this has many applications on data compression. The great disadvantage of the automatic form of fractal compression is its encoding time. Most of the time spent in construction of such operator is due on finding the best match between parts of the image to be encoded. However, since the conception of automatic fractal image compression, researches on improvement of the compression time are widespread. This work aims to provide a new idea for decrease the encoding time: a classification of image parts based on their local fractal dimension. The idea is implemented on two steps. First, a preprocessing analysis of the image identify the complexity of each image block computing its dimension. Then, only parts within the same range of complexity are used for testing the better self-affine pairs, reducing the compression time. The performance of this proposition, is compared with others fractal image compression methods. The points considered are image fidelity, encoding time and amount of compression on the image file.
An Edge-Extraction Based Fractal Image Coding Approach
基于边缘提取的分形图象编码方法

WANG Xue-jun,
王学军
,陈贺新

中国图象图形学报 , 2001,
Abstract: Fractal coding of digital image offers many promising qualities. However the coding process suffers from the long search time of the matching between range blocks and domain blocks. So, classifying the blocks is usually used to reduce the long search time. The classifying is based on the special characters of the image blocks. And the special characters are presented as smooth area, edge area and texture area in an image. For an image block, smooth area can be considered as non-edge area, texture area also can be considered as quickly changed edge area. So important information of image character can be obtained through edge extraction. Edge extraction usually takes the use of several edge-detecting operators such as Sobel and Laplacian operators. Here, a Laplacian operator is applied in original image first because the operator can detect edge image with quickly changed. Then, from the edge image after above operation, a given-threshold gray level image is removed. So a redunance-removed and an edge character prominent image is obtained. This image is used for domain blocks classification. And several parameters are obtained by statistics or multiplied from the image. Finally 4 big classes and 12 small classes are derived from above parameters and all classes are used for fractal image coding.The proposed fractal method is tested by real gray level images under windows 98 platform with visual C language. For encoding an image effectively, in this paper, a quad-tree structure is used for image segmentation so that the encoding algorithm is an automatic iterative algorithm.Computer encoding and decoding simulation result shows that compared with other similar methods, the proposed fractal method can make more accurate and objective classifications, and has an improved encoding speed, compression ratio and can provide a better reconstructed image quality.
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