Издательство InTech, 2011, -378 pp.The discrete wavelet transform (DWT) has an established role in multi-scale processing of biomedical signals, such as EMG and EEG. Since DWT algorithms provide both octave-scale frequency and spatial timing of the analyzed signal. Hence, DWTs are constantly used to solve and treat more and more advanced problems. The DWT algorithms were initially based on the compactly supported conjugate quadrature filters (CQFs). However, a drawback in CQFs is due to the nonlinear phase effects such as spatial dislocations in multi-scale analysis. This is avoided in biorthogonal discrete wavelet transform (BDWT) algorithms, where the scaling and wavelet filters are symmetric and linear phase. The biorthogonal filters are usually constructed by a ladder-type network called lifting scheme. Efficient lifting BDWT structures have been developed for microprocessor and VLSI environment. Only integer register shifts and summations are needed for implementation of the analysis and synthesis filters. In many systems BDWT-based data and image processing tools have outperformed the conventional discrete cosine transform (DCT) -based approaches. For example, in JPEG2000 Standard the DCT has been replaced by the lifting BDWT.
A difficulty in multi-scale DWT analyses is the dependency of the total energy of the wavelet coefficients in different scales on the fractional shifts of the analysed signal. This has led to the development of the complex shift invariant DWT algorithms, the real and imaginary parts of the complex wavelet coefficients are approximately a Hilbert transform pair. The energy of the wavelet coefficients equals the envelope, which provides shift-invariance. In two parallel CQF banks, which are constructed so that the impulse responses of the scaling filters have half-sample delayed versions of each other, the corresponding wavelet bases are a Hilbert transform pair. However, the CQF wavelets do not have coefficient symmetry and the nonlinearity disturbs the spatial timing in different scales and prevents accurate statistical analyses. Therefore the current developments in theory and applications of shift invariant DWT algorithms are concentrated on the dual-tree BDWT structures. The dual-tree BDWTs have appeared to outperform the real-valued BDWTs in several applications such as denoising, texture analysis, speech recognition, processing of seismic signals and multiscale-analysis of neuroelectric signals.
This book reviews the recent progress in DWT algorithms for biomedical applications. The book covers a wide range of architectures (e.g. lifting, shift invariance, multi-scale analysis) for constructing DWTs. The book chapters are organized into four major parts. Part I describes the progress in implementations of the DWT algorithms in biomedical signal analysis. Applications include compression and filtering of biomedical signals, DWT based selection of salient EEG frequency band, shift invariant DWTs for multiscale analysis and DWT assisted heart sound analysis. Part II addresses speech analysis, modeling and understanding of speech and speaker recognition. Part III focuses biosensor applications such as calibration of enzymatic sensors, multiscale analysis of wireless capsule endoscopy recordings, DWT assisted electronic nose analysis and optical fibre sensor analyses. Finally, Part IV describes DWT algorithms for tools in identification and diagnostics: identification based on hand geometry, identification of species groupings, object detection and tracking, DWT signatures and diagnostics for assessment of ICU agitation-sedation controllers and DWT based diagnostics of power transformers.
The chapters of the present book consist of both tutorial and highly advanced material. Therefore, the book is intended to be a reference text for graduate students and researchers to obtain state-of-the-art knowledge on specific applications. The editor is greatly indebted to all co-authors for giving their valuable time and expertise in constructing this book. The technical editors are also acknowledged for their tedious support and help.Part 1 Biomedical Signal Analysis
Biomedical Applications of the Discrete Wavelet Transform
Discrete Wavelet Transform in Compression and Filtering of Biomedical Signals
Discrete Wavelet Transform Based Selection of Salient EEG Frequency Band for Assessing Human Emotions
Discrete Wavelet Transform Algorithms for Multi-Scale Analysis of Biomedical Signals
Computerized Heart Sounds Analysis
Part 2 Speech Analysis
Modelling and Understanding of Speech and Speaker Recognition
Discrete Wavelet Transform & Linear Prediction Coding Based Method for Speech Recognition via Neural Network
Part 3 Biosensors
Implementation of the Discrete Wavelet Transform Used in the Calibration of the Enzymatic Biosensors
Multiscale Texture Descriptors for Automatic Small Bowel Tumors Detection in Capsule Endoscopy
Wavelet Transform for Electronic Nose Signal Analysis
Wavelets in Electrochemical Noise Analysis
Applications of Discrete Wavelet Transform in Optical Fibre Sensing
Part 4 Identification and Diagnostics
Biometric Human Identification of Hand Geometry Features Using Discrete Wavelet Transform
Wavelet Signatures of Climate and Flowering: Identification of Species Groupings
Multiple Moving Objects Detection and Tracking Using Discrete Wavelet Transform
Wavelet Signatures and Diagnostics for the Assessment of ICU Agitation-Sedation Protocols
Application of Discrete Wavelet Transform for Differential Protection of Power Transformers
