We present a new fractalcoding scheme to find more optimal transformations using reference images, which are employed as seeds for obtaining candidates for the optimal transformations. Each transformation that minimi...
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We present a new fractalcoding scheme to find more optimal transformations using reference images, which are employed as seeds for obtaining candidates for the optimal transformations. Each transformation that minimizes the distance between an original image and a reference image is a candidate. It is actually impossible to find optimal transformation due to heavy computation. Thus, instead of considering all of the allowable transformations, we select a few transformations as candidates for the optimal transformation, and thereafter select the best from that group. Our scheme can be considered a "generalized collage coding scheme," since its process for each reference image is similar to the collage coding process. That is, the collage coding scheme is a special case in our scheme, with only one reference image. At first, in a simple case where the optimal transformation can be obtained, our scheme is experimentally evaluated, as compared with the optimal one. In general cases where the optimal one is unavailable, our scheme is also evaluated compared to conventional schemes. (C) 2001 Society of Photo-Optical Instrumentation Engineers.
In this paper, we propose a novel scheme of automatic image authentication and recovery, in which the altered region of the image can be detected and recovered in a fully automated fashion. To achieve high-quality ima...
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In this paper, we propose a novel scheme of automatic image authentication and recovery, in which the altered region of the image can be detected and recovered in a fully automated fashion. To achieve high-quality image recovery, we choose the region of importance (ROI) in the image and perform fractal encoding for the blocks of ROI. And then we insert the fractal codes of ROI and the watermark into the original image to obtain the watermarked image. By watermark extraction, we can determine whether the watermarked image has been tampered or not. If the watermarked image has been tampered, we can automatically localize the altered region, and apply either fractal decoding or image inpainting for image recovery. Finally, experimental results are given to show the effectiveness of the proposed scheme. (c) 2007 Pattern Recognition Society. Published by Elsevier Ltd. All rights reserved.
A new fast fractal encoding algorithm based on the variances of image blocks is proposed. With the domain blocks sorted according to their variances, and the best matched domain block to a given range block is searche...
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A new fast fractal encoding algorithm based on the variances of image blocks is proposed. With the domain blocks sorted according to their variances, and the best matched domain block to a given range block is searched in the order that the variance-distance is closer. A great number of domain blocks could be safely rejected by the prior comparison of the current minimum distortion and variance difference between the candidate domain block and the range block during the search process. It was proved that our algorithm produces completely identical fractal codes with that of the conventional full search in reduced time. The simulation results confirmed the effectiveness of the proposed algorithm.
This paper revisits the concept of fractal image coding and the contractivity conditions of the fractal transform operator. All such existing conditions are only sufficient. This paper formulates a necessary and suffi...
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This paper revisits the concept of fractal image coding and the contractivity conditions of the fractal transform operator. All such existing conditions are only sufficient. This paper formulates a necessary and sufficient condition for the contractivity of the fractal transform operator associated to a fractal code. Furthermore, analytical results on the convergence of the fractalimage decoding will be derived.
fractal image coding has been used successfully to compress and segment images, and more recently, utilized in a new distance measure to recognize objects. This paper discusses how the process of decoding a set of reg...
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fractal image coding has been used successfully to compress and segment images, and more recently, utilized in a new distance measure to recognize objects. This paper discusses how the process of decoding a set of region-based contractive transformations has invariance properties that can be advantageous in object recognition. We will show that the recognition ability of the proposed fractal neighbor classifier (FNC), utilizing the fractal neighbor distance (FND) measure is a function of the contrast scaling factor and the illumination shift factor. Our investigation of the FND required accurate control over the convergence of a fractal decoding process. Convergence can be determined by examining the contractivity and eventual contractivity factors. We have derived theorems that allow these two factors to be calculated for a general class of fractal codes consisting of affine trans formations with integral geometric scaling. Experiments were performed that verified our ability to control and modify these convergence properties. Furthermore, experiments on human face recognition revealed that the performance of the FNC improved through the use of eventual convergence and the imposition of limits on the illumination shift factor. (C) 2002 Pattern Recognition Society. Published by Elsevier Science Ltd. All rights reserved.
The goal of this paper is to present a new recipe for the fractalimage decoding process. In this paper, we explain how fractal-based methods can be internally combined with regularization schemes, e.g., Tikhonov, Tot...
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ISBN:
(纸本)9781424400379
The goal of this paper is to present a new recipe for the fractalimage decoding process. In this paper, we explain how fractal-based methods can be internally combined with regularization schemes, e.g., Tikhonov, Total Variation (TV), or Hard-Constrained regularization. Although the regularization procedure is very common in context of algebraic image restoration, it has not yet been thought directly in the context of fractal-based methods. This implication can be advantageous in many ways to improve the quality of the decoded image depending on the regularization functional. We develop the theory and apply the standard iterative methods of steepest descent and projected Landweber. We apply our technique to the under-determined missing fractal code problem as verification to the theory presented.
fractalimage compression is a new technique in image compression field based on Affine contractive transforms. fractalimage compression methods belong to different categories according to the different theories they...
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ISBN:
(纸本)0769523161
fractalimage compression is a new technique in image compression field based on Affine contractive transforms. fractalimage compression methods belong to different categories according to the different theories they are based on. All of those are discussed in this paper. In the end a conclusion is made to summarize the characters of fractalimage compression.
An image denoising and enhancement algorithm based on fractalcoding in wavelet domain is presented. Among them, A lemma is introduced first, and the advantages of fractalcoding in wavelet domain are analyzed. Then, ...
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ISBN:
(数字)9781510634107
ISBN:
(纸本)9781510634107
An image denoising and enhancement algorithm based on fractalcoding in wavelet domain is presented. Among them, A lemma is introduced first, and the advantages of fractalcoding in wavelet domain are analyzed. Then, the denoising algorithm and experimental results based on fractalcoding in wavelet domain are given in detail, and the experimental results are analyzed. When the noise level is high, the denoising effect of this method is better than that of the general method, and has higher logarithmic signal-to-noise ratio and peak logarithmic signal-to-noise ratio. At the same time, the calculation amount of this algorithm is smaller and the precision is higher.
fractal image coding is a novel way in image compression community, for which quite a number of algorithms or schemes have been devised during the, last decade. In this paper, we propose a general framework model afte...
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ISBN:
(纸本)0780374908
fractal image coding is a novel way in image compression community, for which quite a number of algorithms or schemes have been devised during the, last decade. In this paper, we propose a general framework model after the overview of principal publishments, which helps to understand common problems and. design effective schemes. An implementation on this model with free-shaped region partition is also introduced. Our highly image-adaptive scheme can achieve coding gains of 1.0-1.5 dB for compression ratios larger than 10:1 in comparison with conventional quadtree scheme.
In order to improve the drawback of fractalimage encoding with full search typically requires a very long runtime. This paper thus proposed an effective algorithm to replace algorithm with full search, which is mainl...
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ISBN:
(纸本)9783319538389;9783319538372
In order to improve the drawback of fractalimage encoding with full search typically requires a very long runtime. This paper thus proposed an effective algorithm to replace algorithm with full search, which is mainly based on newly-defined coefficient of variation feature of image block. During the search process, the coefficient of variation feature is utilized to confine efficiently the search space to the vicinity of the domain block having the closest coefficient of variation feature to the input range block being encoded, aiming at reducing the searching scope of similarity matching to accelerate the encoding process. Simulation results of three standard test images show that the proposed scheme averagely obtain the speedup of 4.67 times or so by reducing the searching scope of best-matched block, while can obtain the little lower quality of the decoded images against the full search algorithm. Moreover, it is better than the moment of inertia algorithm.
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