Signal Processing Commons^™

Antennas For Portable Communications In The Uwb And Gps Spectra., Giuseppe Ruvio

Doctoral

The thesis describes a study of antennas for solutions in emerging systems. An account of the fundamental principles of these antennas is given together with an outline of the basic electromagnetic theory on which the designs are based. While the main focus is on antennas for Ultra Wideband (UWB) systems, some additional work was carried out on enhancing performance of circularly polarised antennas for satellite navigation systems. The study focussed on the design of highly efficient broadband antennas with particular requirements for size compactness, gain stability, phase-linearity, and the use of low-cost materials. These requirements are particularly important for UWB …

Audio Data Verification And Authentication Using Frequency Modulation Based Watermarking, Jonathan Blackledge, Omar Farooq

Articles

An approach to watermarking digital signals using frequency modulation - ‘Chirp Coding’ - is considered. The principles underlying this approach are based on the use of a matched filter to reconstruct a ‘chirp stream’ code that is uniquely robust. The method is generic in the sense that it can, in principle, be used for a variety of different signal (the authentication of speech and biomedical signals, for example). Further, by generating a bit stream that is signal dependent, chirp coding provides a method of self-authentication, which has a wide range of applications including copyright protection and digital rights management. However, …

Music Structure Segmentation Using The Azimugram In Conjunction With Principal Component Analysis, Dan Barry, Mikel Gainza, Eugene Coyle

Conference papers

A novel method to segment stereo music recordings into formal musical structures such as verses and choruses is presented. The method performs dimensional reduction on a time-azimuth representation of audio which results in a set of time activation sequences, each of which corresponds to a repeating structural segment. This is based on the assumption that each segment type such as verse or chorus has a unique energy distribution across the stereo field. It can be shown that these unique energy distributions along with their time activation sequences are the latent principal components of the time-azimuth representation. It can be shown …

Automatic Bar Line Segmentation, Mikel Gainza, Dan Barry, Eugene Coyle

Conference papers

A method that segments the audio according to the position of the bar lines is presented. The method detects musical bars that frequently repeat in different parts of a musical piece by using an audio similarity matrix. The position of each bar line is predicted by using prior information about the position of previous bar lines as well as the estimated bar length. The bar line segmentation method does not depend on the presence of percussive instruments to calculate the bar length. In addition, the alignment of the bars allows moderate tempo deviations.

A Brief Introduction To Speech Synthesis And Voice Modification, Alan O'Cinneide, David Dorran, Mikel Gainza

Conference papers

For both engineers and linguists, the computer synthesis of natural speech is an objective that would provide many useful applications to human-computer interaction, including the realm of electro-acoustic music. The purpose of this paper is to introduce the area of speech synthesis by providing an overview of the three main methods of computer speech synthesis; namely concatenative, articulatory and formant syntheses. Some aspects of the current state of the technology are illuminated and the final section will explain the author’s motivation and current research approach to the field of voice modification.

Blind Source Separation And Automatic Transcription Of Music Using Tensor Decompositions, Derry Fitzgerald

Conference papers

Recent advances in the use of tensor decompositions for the analysis of music are described. In particular, the use of such decompositions for sound source separation and the automatic transcription of music are explored.

Digital Signal Processing (Second Edition), Jonathan Blackledge

Books/Book chapters

This book provides an account of the mathematical background, computational methods and software engineering associated with digital signal processing. The aim has been to provide the reader with the mathematical methods required for signal analysis which are then used to develop models and algorithms for processing digital signals and finally to encourage the reader to design software solutions for Digital Signal Processing (DSP). In this way, the reader is invited to develop a small DSP library that can then be expanded further with a focus on his/her research interests and applications.

There are of course many excellent books and software …

Digital Image Processing, Jonathan Blackledge

Books/Book chapters

Newspapers and the popular scientific press today publish many examples of highly impressive images. These images range, for example, from those showing regions of star birth in the distant Universe to the extent of the stratospheric ozone depletion over Antarctica in springtime, and to those regions of the human brain affected by Alzheimer’s disease. Processed digitally to generate spectacular images, often in false colour, they all make an immediate and deep impact on the viewer’s imagination and understanding.

Professor Jonathan Blackledge’s erudite but very useful new treatise Digital Image Processing: Mathematical and Computational Methods explains both the underlying theory and …

Non-Negative Tensor Factorisation For Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle

Conference papers

An algorithm for Non-negative Tensor Factorisation is introduced which extends current matrix factorisation techniques to deal with tensors. The effectiveness of the algorithm is then demonstrated through tests on synthetic data. The algorithm is then employed as a means of performing sound source separation on two channel mixtures, and the separation capabilities of the algorithm demonstrated on a two channel mixture containing saxophone, strings and bass guitar.

Onset Detection, Music Transcription And Ornament Detection For The The Traditional Irish Fiddle, Aileen Kelleher, Derry Fitzgerald, Eugene Coyle, Robert Lawlor, Mikel Gainza

Conference papers

By combining techniques used in previous onset detectors, a system that detects note onsets in traditional Irish fiddle tunes has been implemented. The notes detected also include the most common types of ornamentation played by the fiddle. Ornaments are notes of extremely short duration, at most a fifth the length of a regular note. A Short Time Fourier Transform based sub-band technique, which previously gave good results for the Irish tin whistle, was modified to include a threshold approximation more suitable for the fiddle. This system has been tested on a database of real recorded fiddle tunes and good results …

Development Of A Computer-Based Violin Teaching Aid: Vitool, Jane Charles, Derry Fitzgerald, Eugene Coyle

Conference papers

This paper considers the development of a violin teaching aid, called ViTool, which is based on violin pedagogy, sound analysis, and comparison of beginner and good player recordings. It is a computer based teaching aid and will ultimately consist of at least four task dependent tools. Typical beginner faults have been identified and features, that best describe them for classification purposes, are considered. The ViTool is not intended as a replacement or electronic teacher, but as a teaching aid. Presently, it seems that no such violin learning aid or tool exists and an opportunity exists for the development of such …

Single Channel Source Separation Using Short-Time Independent Component Analysis, Dan Barry, Derry Fitzgerald, Eugene Coyle

Conference papers

In this paper we develop a method for the sound source separation of single channel mixtures using Independent Component Analysis within a time-frequency representation of the audio signal. We apply standard Independent Component Analysis techniques to contiguous magnitude frames of the short-time Fourier transform of the mixture. Provided that the amplitude envelopes of each source are sufficiently different, it can be seen that it is possible to recover the independent short-time power spectra of each source. A simple scoring scheme based on auditory scene analysis cues is then used to overcome the source ordering problem ultimately allowing each of the …

Drum Transcription In The Presence Of Pitched Instruments Using Prior Subspace Analysis, Derry Fitzgerald, Robert Lawlor, Eugene Coyle

Conference papers

This paper demonstrates the use of Prior Subspace Analysis (PSA) as a method for transcribing drums in the presence of pitched instruments. PSA uses prior subspaces that represent the sources to be transcribed to overcome some of the problems associated with other subspace methods such as Independent Subspace Analysis (ISA) or sub-band ISA. The use of prior knowledge results in improved robustness for transcription purposes and enables the method to work more readily in the presence of pitched instruments than other subspace methods. The system presented in this paper attempts to extend the use of PSA to transcribe drum sounds …

System Identification Using Higher Order Spectra, Aidan O'Dwyer

Conference papers

This communication will explore the use of particular types of frequency domain concepts, labelled higher order spectra, to help determine the frequency response of a process. This will allow the identification of the parameters of a single input, single output (SISO) model for a process (which includes a time delay), in both open loop and closed loop environments.

Sub-Band Independent Subspace Analysis For Drum Transcription, Derry Fitzgerald, Robert Lawlor, Eugene Coyle

Conference papers

While Independent Subspace Analysis provides a means of separating sound sources from a single channel signal, making it an effective tool for drum transcription, it does have a number of problems. Not least of these is that the amount of information required to allow separation of sound sources varies from signal to signal. To overcome this indeterminacy and improve the robustness of transcription an extension of Independent Subspace Analysis to include sub-band processing is proposed. The use of this approach is demonstrated by its application in a simple drum transcription algorithm.

Time Delay Estimation In Signal Processing Applications: An Overview, Aidan O'Dwyer

Conference papers

An extensive though scattered literature exists on the estimation of time delays in signal processing applications. However, it is possible to identify themes that are common to many of the available techniques. The intention of this paper is to provide a framework against which the literature may be viewed. In addition, original work on gradient based time delay estimation is described.