A new implementation of the Discrete wavelet Irans- form is presented for applications such as image restoration and enhancement. It employs a dual tree of wavelet filters to obtain the real and imaginary parts of the...
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A new implementation of the Discrete wavelet Irans- form is presented for applications such as image restoration and enhancement. It employs a dual tree of wavelet filters to obtain the real and imaginary parts of the complex wavelet coefficients. Ihis introduces limited redundancy (4 : 1 for 2-dimensional signals) and allows the transform to provide approximate shift in variance and directionally selective filters (properties lacking in the traditional wavelet transform) while preserving the usual properties of perfect reconstruction and computational efficiency. We show how the dual-Tree complex wavelet transform can provide a good basis for multi- resolution image denoising and de-blurring.
Suppose that (sigma) is a sigmoidal function which is the activation function of a neural network. Under certain assumptions on the derivatives of σ, we show that a simple linear combination of dilates and translates...
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The wavelet transform and inverse transform algorithm are introduced. The medical image plays an important role in clinical diagnosis and therapy of doctor and teaching and researching. This paper gives reviews of som...
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ISBN:
(纸本)0780384032
The wavelet transform and inverse transform algorithm are introduced. The medical image plays an important role in clinical diagnosis and therapy of doctor and teaching and researching. This paper gives reviews of some applications in medical image with wavelet, such as ECG signalprocessing, EEG signalprocessing, medical image compression, medical image reinforcing and edge detection, medical image register. With the further development of wavelet theory, wavelet transform will be widely applied to the domain of medical image.
Quincunx sampling is of big interest for image coding applications. Recent remote sensors of satellites return quincunx sampled images. Moreover, a quineunx sampling allows the decomposition of the image into two chan...
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ISBN:
(纸本)0780362985
Quincunx sampling is of big interest for image coding applications. Recent remote sensors of satellites return quincunx sampled images. Moreover, a quineunx sampling allows the decomposition of the image into two channels and a twice as accurate multiresolution analysis as the dyadic one. This paper introduces a new construction of quincunx wavelet transform. This new transform is a bidimensional extension of the factorization of wavelet transform into lifting scheme for finite and symmetrical low pass filters. The: aim of this method is to deal with quincunx images with appropriate transforms while using advantages offered by the lifting scheme. This method allows us to find new efficient quineunx wavelet filters.
We address the problem of improving the performance of wavelet based fractal image compression by applying efficient triangulation methods. We construct iterative function systems (IFS) in the tradition of Barnsley an...
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ISBN:
(纸本)0819429139
We address the problem of improving the performance of wavelet based fractal image compression by applying efficient triangulation methods. We construct iterative function systems (IFS) in the tradition of Barnsley and Jacquin, using non-uniform triangular range and domain blocks instead of uniform rectangular ones. We search for matching domain blocks in the manner of Zhang and Chen, performing a fast wavelet transform on the blocks and eliminating low resolution mismatches to gain speed. We obtain further improvements by the efficiencies of binary triangulations (including the elimination of affine and symmetry calculations and reduced parameter storage), and by pruning the binary tree before construction of the IFS. Our wavelets are triangular Haar wavelets and "second generation" interpolation wavelets as suggested by Sweldens' recent work.
wavelet thresholding is a powerful tool for denoising images and other signals with sharp discontinuities. Using different wavelet bases gives different results, and since the wavelet transform is not time-invariant, ...
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ISBN:
(纸本)0819450804
wavelet thresholding is a powerful tool for denoising images and other signals with sharp discontinuities. Using different wavelet bases gives different results, and since the wavelet transform is not time-invariant, thresholding various shifts of the signal is one way to use different wavelet bases. This paper describes several denoising methods that apply wavelet thresholding or variations on wavelet thresholding recursively. (We previously termed one of these methods "recursive cycle spinning.") These methods are compared experimentally for denoising piecewise polynomial signals. Though similar, the methods differ in computational complexity, convergence speed, and sensitivity to threshold selection.
In this work a new way to improve the representation of images using a discrete wavelet transform for coding purposes is presented. The idea lies in combining all wavelet coefficients related to detail information at ...
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ISBN:
(纸本)0818679204
In this work a new way to improve the representation of images using a discrete wavelet transform for coding purposes is presented. The idea lies in combining all wavelet coefficients related to detail information at a same resolution level but along different orientations (horizontal, vertical, and diagonal), into a single image. Given that detail information is located for all subband images in the neighborhood of high frequency textures or edge locations, the pattern of significant coefficients remains unchanged after the combination process. This process allows further to reduce the number of transformed coefficients by 2/3, while preserving the multiresolution structure. This information can thus be efficiently coded using a multiresolution embedded coding scheme, such as Shapiro's zerotree coder. Overall, a higher coding efficiency can be reached while preserving the cross-scale prediction of significance among coefficients. Ultimately, approximate detail information must be recovered from the combined and coded data for each subband of the original wavelet, so as to reconstruct a decoded image.
On the base of local criteria of processing quality, a class of local adaptive linear filters for image restoration and enhancement is introduced. The filters work in a running window in the domain of DFT of DCT and h...
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ISBN:
(纸本)0819422134
On the base of local criteria of processing quality, a class of local adaptive linear filters for image restoration and enhancement is introduced. The filters work in a running window in the domain of DFT of DCT and have O (size of the window) computational complexity thanks to recursive algorithms of running DFT and DCT. The filter design and the recursive computation of running DCT are outlined and filtering for edge preserved noise suppression, blind image restoration and enhancement is demonstrated.
Density conditions have turned out to be a powerful tool for deriving necessary conditions for weighted wavelet systems to possess an upper or lower frame bound. In this paper we study different definitions of density...
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ISBN:
(纸本)0819450804
Density conditions have turned out to be a powerful tool for deriving necessary conditions for weighted wavelet systems to possess an upper or lower frame bound. In this paper we study different definitions of density and compare them with respect to their appropriateness and practicality.
Dyadic wavelet transform has been used to derive affine invariant functions. The invariant functions are based on the dyadic wavelet transform of the object boundary. Two invariant functions have been calculated using...
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ISBN:
(纸本)0819437646
Dyadic wavelet transform has been used to derive affine invariant functions. The invariant functions are based on the dyadic wavelet transform of the object boundary. Two invariant functions have been calculated using different numbers of dyadic levels. Experimental results show that these invariant functions outperform some traditional invariant functions. The stability of these invariant functions have been tested for a large perspective transformation.
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