We investigate the application of adaptive wavelets for the representation and classification of signals in digitized speech and medical images. A class of wavelet basis functions are used to extract features from the...
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ISBN:
(纸本)0819425915
We investigate the application of adaptive wavelets for the representation and classification of signals in digitized speech and medical images. A class of wavelet basis functions are used to extract features from the regions of interest. These features are then used in an artificial neural network to classify the region as containing the desired object or belonging to the background clutter. The dilation and shift parameters of the wavelet functions are not fixed. These parameters are included in the training scheme. In this way the wavelets are adaptive to the expected shape and size of the signals. The results indicate that adaptive wavelet functions may outperform the classical fixed wavelet analysis in detection of subtle objects.
Multiscale processing, in particular using the wavelet transform, has emerged as an incredibly effective paradigm for signalprocessing and analysis. In this paper, we discuss a close relative of the Haar wavelet tran...
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ISBN:
(纸本)0819437646
Multiscale processing, in particular using the wavelet transform, has emerged as an incredibly effective paradigm for signalprocessing and analysis. In this paper, we discuss a close relative of the Haar wavelet transform, the multiscale multiplicative decomposition. While the Haar transform captures the differences between signal approximations at different scales, the multiplicative decomposition captures their ratio. The multiplicative decomposition has many of the properties that have made wavelets so successful. Most notably, the multipliers are a sparse representation for smooth signals, they have a dependency structure similar to wavelet coefficients, and they can be calculated efficiently. The multiplicative decomposition is also a more natural signal representation than the wavelet transform for some problems. For example, it is extremely easy to incorporate positivity constraints into multiplier domain processing. In addition, there is a close relationship between the multiplicative decomposition and the Poisson process;a fact that has been exploited in the field of photon-limited imaging. In this paper, we will show that the multiplicative decomposition is also closely tied with the Kullback-Leibler distance between two signals. This allows us to derive an n-term KL approximation scheme using the multiplicative decomposition.
It has been a desire of a design engineer to combine various toots of analysis and apply them on one problem at hand. In this paper, we propose an algorithm that combines two signalprocessing analysis tools: higher-o...
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ISBN:
(纸本)0819436704
It has been a desire of a design engineer to combine various toots of analysis and apply them on one problem at hand. In this paper, we propose an algorithm that combines two signalprocessing analysis tools: higher-order spectral analysis and wavelets. The computation of polyspectra using conventional approaches involves the use of FFT algorithm. It has been shown that discrete Fourier transform (DFT) can be implemented by a fast algorithm using wavelets. By using this algorithm, polyspectra computational complexity for a certain class of signets reduces to lesser number of computations. In actual implementation, the wavelets in use have to be carefully chosen to balance the benefit of pruning of insignificant data and the price of the transform. Clearly, the optimal choice depends on the class of the data we would encounter. In this paper, we, first, present an introduction of higher-order spectral analysis. Then we discuss wavelet-based fast implementation of DFT and its importance from higher-order spectral analysis viewpoint. Finally, we develop wavelet-based algorithm for computation of polyspectra followed by conclusions.
Bivariate box splines for image interpolation, enhancement, digital filter design, subband coding bank, hexagonal filtering will be discussed. Some existing and new results will be presented. A computational method fo...
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ISBN:
(纸本)0819422134
Bivariate box splines for image interpolation, enhancement, digital filter design, subband coding bank, hexagonal filtering will be discussed. Some existing and new results will be presented. A computational method for box spline image interpolation and box spline digital filters are included.
Transform-based image coders exploit the information packing ability of some mathematical transforms in order to reduce the number of significant transform coefficients needed to accurately represent an image. Large c...
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ISBN:
(纸本)0819422134
Transform-based image coders exploit the information packing ability of some mathematical transforms in order to reduce the number of significant transform coefficients needed to accurately represent an image. Large coefficients are often associated with those regions where an image changes a lot, such as the boundaries between objects with differing visual characteristics. One way to reduce the number of significant transform coefficients is to segment an image into regions of similarity and then apply the transform to each region separately. We propose a novel image compression technique which first segments an image into arbitrary regions and then applies a region-adapted wavelet transform to each region.
The primary goal of this paper is to give examples of the recently developed (finite-field) wavelet coding method by studying the encoder and decoder for some half-rate codes. We propose a decoding methodology based o...
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ISBN:
(纸本)0780370414
The primary goal of this paper is to give examples of the recently developed (finite-field) wavelet coding method by studying the encoder and decoder for some half-rate codes. We propose a decoding methodology based on estimating the polyphase components of the channel error pattern. To demonstrate the striking computational savings of the wavelet coding method over alternatives, we show that bounded-distance decoding of the (24,12,8) Golay code requires only weight computations (or at the worst case, it needs a cyclic lookup table of table size 12). The simplicity and computational savings that finite field wavelets offer for the encoding and decoding of wavelet block codes indicate their powerful capacities for error control coding applications.
In this paper, the novel Q-wave algorithm for image coding is proposed. Q-wave, which provides progressive transmission, is designed with the aim of limiting the computational complexity at the expenses of a slight qu...
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ISBN:
(纸本)0819437646
In this paper, the novel Q-wave algorithm for image coding is proposed. Q-wave, which provides progressive transmission, is designed with the aim of limiting the computational complexity at the expenses of a slight quality degradation with respect to popular coders such as SPIHT. It is particularly suitable for low bit rate compression, and is then promising for applications such as intraframe video coding, Internet browsing, image transmission over band-limited channels. Moreover, Q-wave can be applied also to non standard wavelet decompositions without modifications.
The problem of image feature extraction for classification is difficult because of the high dimensionality inherent in image data. By extracting only relevant image features we reduce the dimensionality of the problem...
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ISBN:
(纸本)0819425915
The problem of image feature extraction for classification is difficult because of the high dimensionality inherent in image data. By extracting only relevant image features we reduce the dimensionality of the problem and improve classification accuracy. We further enhance classification performance by finding an optimal representation of the extracted image features which maximizes separability distance among classes. The principal tools used are Fourier series, wavelet packets, local discriminant basis analysis, and neural networks.
wavelet transform is a powerful and useful mathematical tool for signalprocessing. In this paper detailed description of procedures for numerical integration and derivation in Haar domain has been done. These procedu...
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ISBN:
(纸本)0819450804
wavelet transform is a powerful and useful mathematical tool for signalprocessing. In this paper detailed description of procedures for numerical integration and derivation in Haar domain has been done. These procedures are necessary both in control systems analysis, and, especially, for control design and development. A detailed comparison between classical methods of evaluation and the Haar way is presented and critically discussed.
Overcomplete wavelet representations have become increasingly popular for their ability to provide highly sparse and robust descriptions of natural signals. We describe a method for incorporating an overcomplete wavel...
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ISBN:
(纸本)0819450804
Overcomplete wavelet representations have become increasingly popular for their ability to provide highly sparse and robust descriptions of natural signals. We describe a method for incorporating an overcomplete wavelet representation as part of a statistical model of images which includes a sparse prior distribution over the wavelet coefficients. The wavelet basis functions are parameterized by a small set of 2-D functions. These functions are adapted to maximize the average log-likelihood of the model for a large database of natural images. When adapted to natural images, these functions become selective to different spatial orientations, and they achieve a superior degree of sparsity on natural images as compared with traditional wavelet bases. The learned basis is similar to the Steerable Pyramid basis, and yields slightly higher SNR for the same number of active coefficients. Inference with the learned model is demonstrated for applications such as denoising, with results that compare favorably with other methods.
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