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1993 | Buch

Wavelet Theory and Its Applications

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The continuous wavelet transform has deep mathematical roots in the work of Alberto P. Calderon. His seminal paper on complex method of interpolation and intermediate spaces provided the main tool for describing function spaces and their approximation properties. The Calderon identities allow one to give integral representations of many natural operators by using simple pieces of such operators, which are more suited for analysis. These pieces, which are essentially spectral projections, can be chosen in clever ways and have proved to be of tremendous utility in various problems of numerical analysis, multidimensional signal processing, video data compression, and reconstruction of high resolution images and high quality speech. A proliferation of research papers and a couple of books, written in English (there is an earlier book written in French), have emerged on the subject. These books, so far, are written by specialists for specialists, with a heavy mathematical flavor, which is characteristic of the Calderon-Zygmund theory and related research of Duffin-Schaeffer, Daubechies, Grossman, Meyer, Morlet, Chui, and others. Randy Young's monograph is geared more towards practitioners and even non-specialists, who want and, probably, should be cognizant of the exciting proven as well as potential benefits which have either already emerged or are likely to emerge from wavelet theory.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction/Background
Abstract
Wavelet theory is the mathematics associated with building a model for a signal, system, or process with a set of “special signals.” The special signals are just little waves or “wavelets.” They must be oscillatory (waves) and have amplitudes which quickly decay to zero in both the positive and negative directions (little). See Figure 1.1 for an example of a wavelet (this is a classical wavelet, termed the “Morlet mother wavelet,” after its inventor). The required oscillatory condition leads to sinusoids as the building blocks (see Figure 1.2). The quick decay condition leads is a tapering or windowing Operation (see Figure 1.3). These two conditions must be simultaneously satisfied for the funtion to be a little wave or wavelet. Forming the product of the oscillatory and decay functions yields the waveley of Figure 1.1.
Randy K. Young
Chapter 2. The Wavelet Transform
Abstract
Chapter 1 presented the concepts involved with wavelet theory, especially the scaling operation, and avoided all of the mathematical rigor. This section supports the conceptual statements by providing the mathematical justification. General, continuous-time wavelet transforms are initially discussed. Then the “discrete” wavelet transform is presented. The resolution properties of wavelet transforms are touched upon but then deferred until after ambiguity functions are discussed. For the less mathematically inclined reader the proofs can be avoided without losing continuity.
Randy K. Young
Chapter 3. Practical Resolution, Gain, and Processing Structures
Abstract
Applying wavelet theory in many scientific fields requires general design criteria or performance measures that can be traded off against one another. The tradeoffs between using wavelet transforms versus other transforms are usually stated in terms of resolutions, gains, robustness, noise immunity, and many other criteria. For wideband signals and systems the criteria are often measured with uncertainty functions, point-spread functions, and ambiguity functions.
Randy K. Young
Chapter 4. Wavelet Theory Extensions and Ambiguity Functions
Abstract
This book began by presenting general, continuous-time wavelet theory. Then general discrete wavelet transforms (both CTWS and DTWS) were presented. Special subsets of the discrete wavelet transforms were then presented, which included the multiresolution and the orthogonal wavelet transforms. Since these special wavelet transforms are extensively employed, this chapter compares these transforms to the less constrained wavelet transforms. A new operator is derived that improves the efficiency and interpretation of the unconstrained wavelet transforms and, in general, extends wavelet theory. Improvements and extensions are achieved for wideband correlation receivers and the wideband ambiguity functions.
Randy K. Young
Chapter 5. Linear Systems Modelling with Wavelet Theory
Abstract
This chapter addresses system modelling with wavelet theory. The previous chapters presented the wavelet theory that is required for this chapter. Multiple, and possibly unconstrained, wavelet transforms and their resolution properties were accentuated. This freedom in the choice of the mother wavelet is critical for formulating system models with wavelet theory. This chapter constructs linear, time-varying system models with wavelet theory. This new system model exploits specific results of the previous chapters; it also justifies the topics covered in the previous chapters.
Randy K. Young
Chapter 6. Wideband Scattering and Environmental Imaging
Abstract
All of the mathematics and wavelet theory in this book can be applied to the problem of characterizing or imaging an environment. Environments can range from a single cell to the entire human body, the layers of earth to outer space, or the particle specks in a drop of water to the whole ocean. The characterization of these environments include modelling the position, motion, and other properties of objects or boundaries in the environment. In addition to identifying specific objects or features, a complete model of a channel or environment (including spreading, dispersion and any other environmental effects) may be desired. Assumptions regarding the environments can be enforced by parametric models (i.e., assume that only one narrowband source is in the environment and it is in the farfield of all sensors - then the characterization of the environment can be performed by closed form models and estimators).
Randy K. Young
Backmatter
Metadaten
Titel
Wavelet Theory and Its Applications
verfasst von
Randy K. Young
Copyright-Jahr
1993
Verlag
Springer US
Electronic ISBN
978-1-4615-3584-3
Print ISBN
978-1-4613-6593-8
DOI
https://doi.org/10.1007/978-1-4615-3584-3