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Signal Filtering and Prediction

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lightbulbAbout this topic
Signal filtering and prediction is a field of study focused on the analysis and manipulation of signals to remove noise and extract meaningful information, as well as the use of mathematical models and algorithms to forecast future values or behaviors based on historical data.
lightbulbAbout this topic
Signal filtering and prediction is a field of study focused on the analysis and manipulation of signals to remove noise and extract meaningful information, as well as the use of mathematical models and algorithms to forecast future values or behaviors based on historical data.

Key research themes

1. How can advanced filtering methods improve signal tracking and prediction performance in dynamic, noisy environments?

This research theme focuses on the development and analysis of advanced filtering algorithms that enable accurate tracking and prediction of time-varying signals corrupted by noise. It examines the optimality, computational efficiency, and robustness of filters such as Kalman filters, adaptive filters (LMS, RLS), and their combinations, with particular attention to their performance in nonstationary or uncertain environments where parameter variation occurs. Understanding and improving filter tracking capabilities directly impact real-time signal estimation tasks in communications, navigation, and control systems.

Key finding: Provides a rigorous derivation and exposition of the Kalman filter as the optimal recursive solution to the linear minimum mean-square error state estimation problem for dynamical systems; establishes that the Kalman filter... Read more
Key finding: Demonstrates that a convex combination of least mean squares (LMS) and recursive least squares (RLS) adaptive filters can approach the optimal tracking performance of the Kalman filter in terms of excess mean-square error and... Read more
Key finding: Introduces a generalized framework for linear prediction problems (LPP) and proposes the Direct Filter Approach (DFA), which directly optimizes real-time filter coefficients to minimize mean squared error tailored to specific... Read more
Key finding: Develops polynomial regression models to predict adaptive filter performance (LMS and recursive LMS) in terms of output fidelity parameters, such as signal-to-noise ratio improvement and correlation, as a function of input... Read more
Key finding: Proposes a novel multiresolution wavelet-based methodology combining noise filtering and predictive modeling inspired by the Kalman filter paradigm; experimental validation shows effective capturing of short- and long-term... Read more

2. What role do fractional Fourier transforms and related techniques play in enhancing signal filtering and feature extraction?

This theme explores the mathematical and optical foundations of fractional Fourier transforms (FrFT) and their applications to signal processing, particularly in filtering chirp signals, synthesizing mutual intensity distributions, and performing filtering and multiplexing in fractional domains. By generalizing classical Fourier analysis via fractional orders, these approaches enable enhanced handling of signals with time-frequency characteristics, providing advanced filtering capabilities and novel perspectives on signal representation and transformation relevant to both theoretical analysis and optical implementations.

Key finding: Establishes the fractional Fourier transform as a continuum of Fourier operators parametrized by an order α, linking it physically to quadratic graded index media that continuously interpolate between identity and Fourier... Read more
Key finding: Develops an optimization framework to synthesize a desired mutual intensity distribution (spatial coherence) of light by filtering a source mutual intensity in fractional Fourier domains; demonstrates that fractional-domain... Read more
Key finding: Demonstrates that chirp noise corresponds to rotated delta functions in the Wigner distribution, which can be transformed into narrow impulse-like representations via fractional Fourier transforms; proposes and experimentally... Read more
Key finding: Explores mathematical relations between fractional Fourier domains, chirp, and wavelet transforms, introducing convolution and filtering operations generalized to fractional domains; shows that under specific conditions these... Read more

3. How can fractal and nonlinear dynamic analysis inform robust signal feature extraction and denoising for prediction applications?

This theme highlights the application of fractal dimension measures and nonlinear dynamical system embeddings to extract robust, noise-resistant features from signals such as speech and biomedical data. By embedding signals in reconstructed phase spaces and applying nonlinear filtering informed by local geometry and fractal characteristics, these approaches seek to improve the discriminative and predictive performance under noisy conditions, supplementing or enhancing classical linear feature extraction methods.

Key finding: Introduces features derived from fractal dimensions of filtered embedded speech signals reconstructed in multidimensional phase-space, demonstrating through automatic speech recognition (ASR) experiments on the Aurora 2... Read more

All papers in Signal Filtering and Prediction

Line Spectrum Frequencies (LSF's) uniquely represent the Linear Predictive Coding (LPC) filter of a speech frame. In many vocoders LSF's are used to encode the LPC parameters. In this paper, an interframe differential coding scheme is... more
Recent, advances in blind channel equalization approiiches and the availabil ity of fast processors have made it, possilile to communicate reliably over long distances through HF communication links. Current research efforts focus on the... more
In this paper we consider the problem of multichannel restoration using both within-and between-channel deterministic information. A multichannel image is a set of image planes that exhibit cross-plane similarity. Existing optimal... more
A novel array signal processing technique is proposed to estimate HF channel parameters including number of paths, their respective direction of arrivals (DOA), delays, Doppler shifts and amplitudes. The proposed technique utilizes the... more
Fourier transforms of fractional order a are defined in a manner such that the common Fourier transform is a special case with order a= 1. An optical interpretation is provided in terms of quadratic graded index media and discussed from... more
A concise introduction to the concept of fractional Fourier transforms is followed by a discussion of their relation to chirp and wavelet transforms. The notion of fractional Fourier domains is developed in conjunction with the Wigner... more
In this paper, we describe a multiple-scale boundary representation based on morphological operations. An object boundary is first progressively smoothed by a number of opening and closing operations using a structuring element of... more