Projections of signals continuous translations into subspaces of multiresolution analysis are considered. Compactly supported orthonormal scaling function Nφ any translation of which has good approximation by means o...
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ISBN:
(纸本)0819419281
Projections of signals continuous translations into subspaces of multiresolution analysis are considered. Compactly supported orthonormal scaling function Nφ any translation of which has good approximation by means of integer translations of the same scaling function, is found for N &le 10. Two estimation characteristics of translation invariance of the multiresolution analysis are suggested. The translation invariance characteristics of new scaling functions and wavelets are compared with those proposed by Daubechies. For N = 2, it is proved that the Daubechies compactly supported scaling function 2φ with highest number of vanishing moments compatible with its support width has optimal translation invariance.
An important consideration in the design of VLSI architectures is that of word size and the consequent data precision if confers. The word size affects the dimension of the final circuit as well as the machine's p...
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We investigate a general subset of 2D, orthogonal, compactly supported wavelets. This subset, which has a simple parameterization, includes all wavelets with a corresponding wavelet (polyphase) matrix, that can be fac...
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ISBN:
(纸本)0819419281
We investigate a general subset of 2D, orthogonal, compactly supported wavelets. This subset, which has a simple parameterization, includes all wavelets with a corresponding wavelet (polyphase) matrix, that can be factored as a product of factors of degree - 1, in one variable. In this paper we consider a particular wavelets with vanishing moments. The number of vanishing moments that can be achieved increases with the increase of the McMillan degrees of the wavelet matrix. We design wavelets with the maximal number of vanishing moments for given McMillan degrees, by solving a set of nonlinear constraints, and discuss their relation to regular, smooth wavelets. Design examples are given for two fundamental sampling schemes, the quincunx and the four-band separable sampling.
imageprocessing techniques using wavelet signal analysis techniques have shown promise in mammography. Wavelet algorithms are compared with traditional image enhancement techniques of unsharp masking and median filte...
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ISBN:
(纸本)0819417823
imageprocessing techniques using wavelet signal analysis techniques have shown promise in mammography. Wavelet algorithms are compared with traditional image enhancement techniques of unsharp masking and median filtering. Computer simulated phantom images were generated containing lesions mimicking masses and microcalcifications. The degree of image enhancement was evaluated by comparing processed and original signal-to-noise (SNR) ratios in such phantom images. Results obtained in this study suggest that imageprocessing algorithms based on the wavelet transform are likely to enhance the visibility of low-contrast features in mammograms.
A good portion of modern signalprocessing deals with statistical signalprocessing and array signalprocessing, in which models of both the signal and the noise are used to attain precise estimates of the underlying ...
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ISBN:
(纸本)0819419214
A good portion of modern signalprocessing deals with statistical signalprocessing and array signalprocessing, in which models of both the signal and the noise are used to attain precise estimates of the underlying signal parameters. These parameters include frequencies of sinusoids, angles of arrival of wavefronts, scatterer location of radar targets, etc. The explicit use of a signal-noise model and the use of an optimal statistical estimator leads to an accuracy and resolution which is clearly superior to the fast Fourier transform (FFT). At low signal-to- noise ratios, the estimators can be made as robust as the FFT. We present applications of superresolution signal estimators to synthetic aperture radar (SAR) and inverse SAR imaging.
This paper interprets 1D intensities in images of Synthetic Aperture Radar (SAR) as interwoven sets of mathematically defined singularities, and the spectrum of singularity strengths has been calculated using wavelets...
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ISBN:
(纸本)0819419281
This paper interprets 1D intensities in images of Synthetic Aperture Radar (SAR) as interwoven sets of mathematically defined singularities, and the spectrum of singularity strengths has been calculated using wavelets. Superposition of spectra from a transect of SAR data from the European Earth Resources Satellite (ERS-1) with the spectra from a SAR simulation based only on local terrain elevation variation shows that there exists a range of singularity strengths in ERS-1 data which are closely described by a topographic model. Modeling the SAR spectra using singularity spectra from Cantor sets and multiplicative cascades only partially helps in defining the SAR signal as a multifractal. The paper proposes that identifying and isolating the singularities in a SAR image for the purposes of classifying images can be assisted by using results from a singularity spectrum. The object of this classification is the resolution of images into regions with stable pixels representing purely a response to topographic relief and distinguishable from responses from land use and terrestrial cover types.
The Air Force Phillips Laboratory is in the process of demonstrating an advanced space surveillance capability with a heterodyne laser radar (ladar) system to be used, among other applications, for range-resolved imag...
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ISBN:
(纸本)0819419214
The Air Force Phillips Laboratory is in the process of demonstrating an advanced space surveillance capability with a heterodyne laser radar (ladar) system to be used, among other applications, for range-resolved imaging. Recently, image domain signal-to-noise rations (SNRs) have been derived both for the intensity projections calculated from the range-resolved reflective data and for image information obtained using linear combinations of the projections. Also, other recent results have indicated that superior image quality is obtained by first converting the heterodyne returns into intensity projections before using tomographic techniques to reconstruct an image, as intensity projections is validated using a laboratory heterodyne setup. In addition, the laboratory results are used to validate the conclusion that intensity projections provide superior image reconstructions.
Expressions for the detected signal reflected from an object using a coherent laser radar system are developed in this paper. Post-processing methods to obtain intensity projection data from the detected signals are d...
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ISBN:
(纸本)0819419214
Expressions for the detected signal reflected from an object using a coherent laser radar system are developed in this paper. Post-processing methods to obtain intensity projection data from the detected signals are derived. image domain signal-to-noise ratios (SNRs) are derived both for images reconstructed using a convolution-backprojection algorithm from range- resolved reflective measurements and for the intensity projection data. The two noise sources considered are photon noise and laser speckle noise. It is shown that the SNR of an individual projection at a point is limited above by one, and the upper limit of the SNR of the reconstructed image is on the order of the square root of the number of projections used to create the image.
The proceedings contains 443 papers from the 1995 IEEE Engineering in Medicine and Biology Annual conference. Topics discussed include: electroencephalographic and magnetoencephalographic signalprocessing;autoregress...
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The proceedings contains 443 papers from the 1995 IEEE Engineering in Medicine and Biology Annual conference. Topics discussed include: electroencephalographic and magnetoencephalographic signalprocessing;autoregressive techniques in signalprocessing;signal filtering techniques;visual evoked potentials;signal estimation;time-frequency analysis and applications;medical image visualization;wavelet-based signal analysis;signal detection and discrimination using wavelets;neuromuscular stimulation and recording;magnetic stimulation;bladder, pain and tactile stimulation;implantable muscle electrodes;wheelchair propulsion kinematics and dynamics;and tele-surgical manipulation and ergonomic simulation.
A photorefractive crystal can be used as a three-dimensionally parallel array of multipliers. In writing the photorefractive gratings, the crystal performs the operation of multiplying the inputs and integrating the r...
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ISBN:
(纸本)081941834X
A photorefractive crystal can be used as a three-dimensionally parallel array of multipliers. In writing the photorefractive gratings, the crystal performs the operation of multiplying the inputs and integrating the resulting products. In readout the photorefractive crystal multiplies the inputs with the stored gratings. The three dimensional array of multipliers is only accessible from the two-dimensional faces. This restricts us to using the photorefractive crystal for outer- products in writing to the full three dimensions of parallelism and inner products in reading out the three dimensions, when we are using a single wavelength system. We have explored issues in using the full three dimensions of parallelism in the real time volume holograph for signalprocessingapplications. These issues are illustrated with our successful implementation of a high-bandwidth large phased-array radar processing system. This example system leads to a new algorithm for processing phased-array-radar data, which has a great advantage in hardware complexity over the classic Widrow algorithm and leads to a significant hardware savings for true-time-delay phased-array-radar control systems.
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