A new fractal watermarking algorithm is proposed, in which the watermark embedded can be extracted well. To achieve high-quality extracted watermark under some image attacks, the algorithm selects a suitable image arb...
详细信息
ISBN:
(纸本)9780769538532
A new fractal watermarking algorithm is proposed, in which the watermark embedded can be extracted well. To achieve high-quality extracted watermark under some image attacks, the algorithm selects a suitable image arbitrarily and performs fractal encoding for the image. Then the image is decoded after the watermark image takes the place of the luminance shifting factor in the fractal codebook. Finally according to sub-block DCT watermarking algorithm, the decoded binary image is embedded into the DCT middle frequency coefficients of the original image to obtain the watermarked image. Experimental results demonstrate the good robustness and invisibility of our approach proposed.
In this paper, a new fractal-based image denoising method is proposed which can reserve the edges and remove the blocky artifacts in a denoised image. Our proposed method employs the decoupling property of the fractal...
详细信息
ISBN:
(纸本)0819459763
In this paper, a new fractal-based image denoising method is proposed which can reserve the edges and remove the blocky artifacts in a denoised image. Our proposed method employs the decoupling property of the fractal code instead of the conventional fractalcoding using the contrast scaling and offset parameters. This decoupling property makes it possible to denoise images more effectively and flexibly. In order to improve the visual quality of a denoised image, a range-block partitioning scheme is used to generate a set of overlapping sub-images, and each of the sub-images is represented by range-block mean values and contrast scaling factors to remove the noise. These sub-images are then averaged to produce an optimal denoised image. Experimental results show that our proposed method can achieve, on average, 4.24dB and 1.09dB increase in PSNR in the low-noise (sigma < 20) and the high-noise (sigma >= 20) conditions, respectively, when compared to an exisiting fractal-based denoising algorithm.
Edge detection is important in many fields such as pattern recognition and computer vision. Many edge detection methods are sensitive to noises because gradients are used to enhance edges. To solve this problem, a new...
详细信息
ISBN:
(纸本)0819447145
Edge detection is important in many fields such as pattern recognition and computer vision. Many edge detection methods are sensitive to noises because gradients are used to enhance edges. To solve this problem, a new edge detection method is proposed in the paper based on local self-similarity. For any pixel in an image, a metric, called as local self-similar coefficient, is defined on its square neighborhood. The square neighborhood blocks are classified into three types: edge block, smooth block and random block. Two theorems have been proven according to the self-similar metric definition and the image block classification. The theorems and experimental results demonstrate that the local self-similar coefficients on edge blocks and smooth blocks are much greater than that on random blocks. Fortunately, it is quite easy to distinguish edge blocks from smooth blocks. A new edge detection algorithm based on these properties is provided in the paper. Several kinds of images, including human pictures and natural scenery, are used to detect edges with the new algorithm, and satisfactory results are obtained. The results show that under noisy conditions, the new algorithm extracts better edges than Sobel method.
fractalimage compression has several useful properties, including resolution independence, high compression ratios, rapid decoding, and subjectively good image quality. Despite this, its adoption has been limited, la...
详细信息
ISBN:
(纸本)0819439886
fractalimage compression has several useful properties, including resolution independence, high compression ratios, rapid decoding, and subjectively good image quality. Despite this, its adoption has been limited, largely because of the very high computational burden of compression. In this paper, an original ASIC design is described which performs the comparisons required for fractalimage compression of grayscale images. The design is based around a pipeline of many individual block comparison units through which the set of domain blocks are propagated. Each unit performs the required comparisons between a single range block and the series of domain blocks, and stores the best possible match. The ASIC is designed using synthesizable VHDL, allowing it to be targeted to virtually any digital technology. The small portions of the design which are specific to a particular application or technology, such as the bus interfaces and memory blocks, have been kept separate from the application-independent portions of the design. Simulations of the design suggests that an actual hardware implementation would be about one thousand times faster than a general purpose microprocessor based on similar IC technology, reducing the time required to optimally compress a 256 x 256 image using 8 x 8 range blocks from a few minutes to a fraction of a second.
A novel no-search fractal compression method is proposed by generating the contracted domain block from domain block with the texture feature of the corresponding range block to improve the quality of reconstruction i...
详细信息
ISBN:
(纸本)9781479925650
A novel no-search fractal compression method is proposed by generating the contracted domain block from domain block with the texture feature of the corresponding range block to improve the quality of reconstruction image. The grey-level of the pixels in contracted domain blocks were increased or decreased from the mean of neighboring four pixels in corresponding domain blocks according to the difference between the value of the corresponding pixels in the range block and the average of this range block. Compared with traditional spatial contraction method, the proposed method increases the number of the 2x2 range blocks whose scale parameters are in the valid range, and that reduces the collage error obviously. Experiments on standard images show that the proposed scheme with new spatial contraction method improves the quality of the reconstructed images with nearly the same time consumption.
This paper presents a fusion scheme for wavelets and fractalimage compression based on the self-similarity of the space-frequency plane of sub-bands after wavelet transformation of images. Various kinds of wavelet tr...
详细信息
This paper presents a fusion scheme for wavelets and fractalimage compression based on the self-similarity of the space-frequency plane of sub-bands after wavelet transformation of images. Various kinds of wavelet transform are examined for the characteristics of their self-similarity and evaluated for the adoption of fractal encoder. The aim of this paper is to reduce the information of the two sets of blocks involved in the fractalimage compression by using the self-similarity of images. And also, the new video encoder using the fusion method of wavelets and fractal adopts the similar manner as the motion compensation technique of MPEG encoder. Experimental results show almost the same PSNR and bits rate as conventional fractalimage encoder by depending on the sampled images through computer simulations.
In this paper, an adaptive searchless fractalimage compression technique in the frequency domain is proposed. Proposed methods aim to improve image compression fidelity criteria in discrete cosine transform domain (D...
详细信息
In this paper, an adaptive searchless fractalimage compression technique in the frequency domain is proposed. Proposed methods aim to improve image compression fidelity criteria in discrete cosine transform domain (DCT). In this work spatial domain, adaptive methods are exercised in discrete cosine domain for optimisation of image encoding. Variance-based selection of image blocks and adaptive threshold are two simple adaptive techniques administered on attaining objectives of image compression. First, range block exclusion adaptive method removes homogenous range blocks before FIC coding. This exclusion consequently recedes the number of range-domain blocks matching operations. Proposed hybrid compression algorithm localises domain block location about range block without searching entire domain pool. Second technique implemented is domain pool size reduction. Variances of range and domain blocks are compared. Domain blocks that are within threshold value are kept in the pool. Finally to further optimise the performance of encoding adaptive threshold in quadtree partitioning is applied in along with variance domain selection approach. Simulation results substantiate that adaptive techniques have higher coding performance in terms of encoding time, peak signal to noise ratio and compression ratio in contrast to the fractalimage encoding without adaptive techniques.
fractal image coding is a novel way in imagecompression community, for which quite a number ofalgorithms or schemes have been devised during thelast decade. In this paper, we propose a generalframework model after the...
详细信息
fractal image coding is a novel way in imagecompression community, for which quite a number ofalgorithms or schemes have been devised during thelast decade. In this paper, we propose a generalframework model after the overview of principalpublishments, which helps to understand commonproblems and design effective schemes. Animplementation on this model with free-shaped regionpartition is also introduced. Our highly image-adaptivescheme can achieve coding gains of 1.0-1.5 dB forcompression ratios larger than 10:1 in comparison withconventional quadtree scheme.
A new fractal watermarking algorithm is proposed,in which the watermark embedded can be extracted *** achieve high-quality extracted watermark under some image attacks,the algorithm selects a suitable image arbitraril...
详细信息
A new fractal watermarking algorithm is proposed,in which the watermark embedded can be extracted *** achieve high-quality extracted watermark under some image attacks,the algorithm selects a suitable image arbitrarily and performs fractal encoding for the *** the image is decoded after the watermark image takes the place of the luminance shifting factor in the fractal *** according to sub-block DCT watermarking algorithm,the decoded binary image is embedded into the DCT middle frequency coefficients of the original image to obtain the watermarked *** results demonstrate the good robustness and invisibility of our approach proposed.
暂无评论