Francis Boland

• Professor at Trinity College Dublin

Resonance Audio is an open source project designed for creating and controlling dynamic spatial sound in Virtual & Augmented Reality (VR/AR), gaming or video experiences. It also provides integrations with popular game development platforms and digital audio workstations (as a preview plugin). Resonance Audio binaural decoder is used in YouTube to...

Full paper available at http://www.aes.org/e-lib/browse.cfm?elib=20344 This paper addresses the calibration of a digital sound projector to an uncertain scene description. In this exploratory study the source is a linear array of loudspeakers parallel to the back wall of a rectangular room. The configuration of this digital projector, using first...

This paper presents some further experiments devised to assess the performance of an expanded number of commercially available Ambisonic microphones. The subjective timbral and spatial quality of five microphones (Soundfield MKV, Core Sound TetraMic, Sennheiser Ambeo, MH Acoustics Eigenmike, and Zoom H2N) is assessed using listening tests and a rec...

Provided are methods and systems for delivering three-dimensional, immersive spatial audio to a user over a headphone, where the headphone includes one or more virtual speaker conditions. The methods and systems recreate a naturally sounding sound field at the user's ears, including cues for elevation and depth perception. Among numerous other pote...

The human ability to localize sound is essential for monitoring the environment and helps us to analyze complex auditory scenes. Although the acoustic cues mediating sound localization have been established, it remains unknown how these cues are represented in human cortex. In particular, it is still a point of contention whether binaural and monau...

With recent advances in Virtual Reality (VR) systems and an increased interest in the medium for gaming and 360-degree cinematic experiences, there is a need to establish a suitable method for comparing audio systems in VR. Typically, VR systems incorporate headphones for playback of dynamic, spatial audio. Several methods of performing comparative...

This paper presents some initial experiments devised to assess the performance of a number of commercially available microphones in capturing 360 audio. The subjective audio quality of four microphones (Soundfield MKV, Core Sound TetraMic, MH Acoustics Eigenmike, & Zoom H2N) was assessed using a modified Multiple Stimuli with Hidden Reference and A...

Provided are methods and systems for updating a sound field in response to user movement. The methods and systems are less computationally expensive than existing approaches for updating a sound field, and are also suitable for use with arbitrary loudspeaker configurations. The methods and systems provide a dynamic binaural sound field rendering re...

The Atomic Force Microscope (AFM) allows the measurement of interactions at interfaces with nanoscale resolution. Imperfections in the shape of the tip often lead to the presence of imaging artefacts such as the blurring and repetition of objects within images. Generally, these artefacts can only be avoided by discarding data and replacing the prob...

This paper further investigates previous findings that coefficients of acoustic responses can be modelled as random polynomials with certain constraints applied. In the case of room impulse responses, the median value of their clustered roots has been shown to be directly related to the reverberation time of the room. In this paper we examine the f...

This paper introduces a method for registering scans acquired by Atomic Force Microscopy (AFM). Due to compromises between scan size, resolution, and scan rate, high resolution data is only attainable in a very limited field of view. The proposed method uses a sparse set of feature matches between the low and high resolution AFM scans and maps them...

In this paper we investigate possibilities and limitations in terms of elevated sound source reproduction using higher order Ambisonics and practical loudspeaker configurations. Reconstructed sound fields are analysed from the point of view of reproduced energy, sound field reconstruction error and distortion of high frequency spectrum which contai...

The detection of early reflections in room impulse responses is of importance to many algorithms including room geometry inference, mixing time determination and speech dereverberation. The detection of early reflections can be hampered by increasing reflection width, as the direct sound undergoes reflection and by overlapping of the reflections, a...

In this paper acoustic responses are examined with respect to the locations of their zeros or roots. This information is then used to inform an analysis of the pitfalls of the most common method of minimum phase approximation and the use of minimum phase versions of acoustic impulse responses. Acoustic polynomials can be shown to inherently have ze...

|We investigated the impact of exploratory head movements on sound localization accuracy using real and virtual 5.1 loudspeaker arrays. Head orientation data in the horizontal plane was provided either by the Microsoft Kinect face-tracking or Oculus Rift's built-in Inertial Measurement Unit (IMU) which resulted in signi�cantly di�erent precision an...

This paper investigates an implication of the clustering, on the complex plane, of the roots of transfer function polynomials obtained from acoustic responses. These polynomials can be the high order transfer functions obtained from room impulse responses or the relatively lower order ones obtained from head related impulse responses. This clusteri...

This paper presents a method of headphone/earphone equalization based upon deconvolution of the headphone impulse response from other acoustic filters in the processing chain. The methods presented are thus applicable to areas such as spatial audio, where input signals are processed with binaural impulse responses. The extraction of low order from...

In this paper we undertook perceptual experiments to determine the allowed di�erences in depth between audio and visual stimuli in stereoscopic-3D environments while being perceived as congruent. We also investigated whether the nature of the environment and stimuli a�ects the perception of congruence. This was achieved by creating an audio-visual...

While automated condition monitoring of rotating machines often use vibration signals for defect detection, diagnosis, and residual life predictions, in this paper, the acoustic noise signal (<; 25 kHz), acquired via non-contact microphone sensors, is used to predict the remaining useful life (RUL). Modulation spectral (MS) analysis of acoustic sig...

A factorization technique is proposed which allows for a direction independent component to be extracted from a set of head related impulse responses (HRIRs). Each individual HRIR is split into a pair of filters, a direction independent component which is common to all HRIRs in the dataset and a direction dependent component which is particular to...

Spatial localisation of sounding objects is affected not only by auditory cues but also by other modalities such as vision. This is true particularly in the context of distance perception where the number of auditory cues is limited in comparison to e.g. localisation in horizontal and vertical planes. In this study we investigate the influence of v...

We present an integrated set of audio-visual tracking and synthesis tools to aid matching of the audio to the video position in both horizontal and periphonic sound reinforcement systems. Compensation for screen size and loudspeaker layout for high definition formats is incorporated and the spatial localisation of the source is rendered using advan...

We present a new method for dereverberating speech, based upon a multichannel Wiener Filter and a microphone array. We demonstrate the effectiveness of this method under real, reverberant conditions and show that the method may be described as a self-steering beamformer. Furthermore, we investigate the performance of the method under simulated cond...

In this paper, we present an investigation into the perception of source distance in interactive virtual auditory environments in the context of First (FOA) and Higher Order Ambisonic (HOA) reproduction. In particular, we investigate the accuracy of sound field reproduction over virtual loudspeakers (headphone reproduction) with increasing Ambisoni...

An automated system is presented for reducing a multi-view lecture recording into a single view video containing a best view summary of active speakers. The system uses skin color detection and voxel-based analysis in locating likely speaker locations. Using time-delay estimates from multiple micro phones, speech activity is analyzed for each speak...

Developments in abstract representations of sound from the field of computer music have potential applications for designers of musical computer games. Research in cognition has identified correlations in the perceptions of visual objects and audio events; - experiments show that test subjects associate certain qualities of graphical shapes with th...

In this paper, we present an improved model for Interaural Time Difference (ITD) estimation in reverberant environments. The Phase Transform (PHAT) weighting function, used in generalized cross correlation is investigated here for application to Interaural Cross Correlation (IACC) measurements from binaural microphones. A binaural model is develope...

This study investigates the frequency response of different headphones in the context of their suitability to virtual binaural reproduction. Acoustic impulse responses of the combined transducer-to-eardrum coupling were measured using an Artificial Pinna/Earcanal simulator. Pairs of measurements were recorded and the time and level differences betw...

In this paper we present a method for spatial audio reproduction over headphones using Head-Related Impulse Response (HRIR) simplification and Ambisonic decoding. The method is shown to significantly reduce computational complexity for real-time audio based rendering by decomposing the directional component of HRIRs into spherical harmonic basis fu...

A fuzzy logic-based approach can be used to simulate human agents in many control situations. Numerous authors have noted that this methodology has advantages for a variety of tasks within the realm of computer music. In this paper, a review of such projects is conducted and a rudimentary example application of fuzzy logic techniques is presented....

In this paper, we present an investigation into the perception of source depth in interactive virtual auditory environments in the context of Higher Order Ambisonic (HOA) reproduction. In particular, we investigate the accuracy of soundfield reproduction over virtual loudspeakers (headphone reproduction) with increasing Ambisonic order. Performance...

HRIR factorisation allows the extraction of a common direction independent component from a set of HRIRs leaving a set of relatively short direction dependent filters and provides both memory and computational savings in real time spatial audio applications. In this paper this technique is improved by introducing weighted regularisation to the iter...

An approach to approximation of Binaural Room Impulse Responses (BRIRs) is presented. Here, a BRIR is considered to have two constituent parts: the anechoic Head Related Impulse Response (HRIR), convolved with the Room Impulse Response (RIR). Each part is approximated individually. The HRIR is partitioned as the convolution of a directional indepen...

We present a method to extract a common subsystem from a HRIR dataset to allow for easier real-time convolution in interactive audio environments and more efficient HRIR in-terpolation. An iterative least squares method is described for this deconvolution operation, and the relation of this method to that of finding the approximate greatest common...

This paper examines the accuracy of audio-video based localization using multiple cameras and multi-microphones. Covariance mapping theory is used to determine the accuracy of audio and video based localization. Both modalities are compared in terms of their ability to provide accurate location estimates of a moving audio-visual source. Relatively,...

The ability to predict the Remaining Useful Life (RUL) of Rotating Machines is a highly desirable function of Automated Condition Monitoring (ACM) systems. Typically, vibration signals are acquired through contact with the machine and used for monitoring. In this paper, a novel implementation of the ubiquitous feature extraction approach Envelope A...

This paper proposes a technique for determining the distance between a sound source and the microphones in an ad-hoc distributed array. The proposed "Range-Finder" algorithm is robust in the presence of reverberation and, in contrast with previously published source-localization techniques, does not require knowledge of the relative positions of th...

This paper proposes a technique for determining the distance between a sound source and the microphones in an array. The proposed “Range-Finder” algorithm is robust in the presence of reverberation and, in contrast with previously published source-localization techniques, does not require knowledge of the relative positions of the microph...

An important pre-processing stage in speech recognition systems is that of extracting phonetically pertinent acoustic features from the speech signal. These features form the basis for discriminative classification and serve as cues for the identification of phonetic events in speech. The paper addresses this by presenting a novel method for the cl...

In this study, we developed an algorithmic method to analyze late contrast-enhanced (CE) magnetic resonance (MR) images, revealing the so-called hibernating myocardium. The algorithm is based on an efficient and robust image registration algorithm. Using ...

The performance of various spatialization techniques is evaluated for a distributed audience using the non-ideal speaker arrangements found in small concert halls. The methods under evaluation are Second Order Ambisonics, Vector Base Amplitude Panning, Delta Stereophony and Spat with B-format Ambisonics encod-ing. Each method is assessed in terms o...

A comparison of several spatialization systems is presented in terms of their localization accuracy under the nonideal listening conditions found in typical small concert halls. Of interest is the effect of real reverberant conditions, noncentral listening positions, and nonsymmetrical speaker arrays on source localization. The data are presented b...

The performance of many human tracking algorithms rely on accurate motion models. Due to the nature of human motion it is often difficult to determine the suitability of a chosen model. It is typically the case that over the tracking duration the characteristics of the observed motion will fit many different models. Commonly used motion models in t...

Accurate localization of objects in an area has many important applications such as speaker localization and in self-reconfigurable networks systems. Methods using cross-correlation at audio and ultrasonic frequencies are prone to false or inaccurate results for partial signal or in the presence of reverberation and noise. In this paper we propose...

Estimating the range between an acoustic source and a microphone is a central problem in microphone-array processing. Although many approaches have been proposed in the literature, these tend to require knowledge of the relative microphone positions. We propose a range estimation method, for use in reverberant environments and where the relative po...

This paper addresses the problem of determining the number of wideband sources in a reverberant environment. In [1] an Exponential Fitting Test (EFT) is proposed based on the exponential profile of the noise only eigenvalues. We consider the performance of this test for the problem in question, and compare it with the results achieved by the well k...

This paper will address the impact of array geometry with respect to adaptive beamforming. The adaptive beamformer under investigation is the Griffiths-Jim Generalised Sidelobe Canceller (GJ-GSC) and we present a new approach to analyze and quantize the error introduced in the GJ-GSC by non-adherence to the far-field assumption. We also show that p...

Time delay estimation (TDE) is used in calculating the direction of arrival (DOA) of speech signals and beamforming. Cross-correlation is a popular method used for TDE. However cross-correlation's performance degrades in the presence of high noise and reverberation. The YIN algorithm is used to determine the fundamental frequency of music and speec...

There are many possible benefits to knowing the location of a singer onstage, for example, for automatic tracking of the singer with lights or cameras. The paper examines the question of locating a singer by finding the time delay between the sound arriving at the radio and stage microphones. Traditional time delay estimation techniques, such as th...

An analysis is presented of the stroboscopic waveform mode for electron beam testing of integrated circuits. The significance of the analysis is the formulation of the relationships between the duration and phase increment of the electron beam and the bandwidth of the signal to be measured. The results provide a strategy for obtaining efficient set...

A method is proposed for processing IC waveforms acquired using the stroboscopic waveform mode. The waveforms are modelled using first-order exponentials and least-squares regression is used to fit the model to the measured waveform. The method is particularly suited to an automated EBT system. An error analysis is included which highlights the rel...

This paper describes a new phase extraction algorithm for 3D optical profilometry based on the projection of a periodic light pattern and phase measurement (phase profilometry). The algorithm uses a square wave to demodulate phase and moving averages and comb-shaped filters to extract the phase information from low frequency. The proposed algorithm...

This paper describes a new phase extraction algorithm for phase profilometry. The algorithm uses a square wave to demodulate phase and moving averages and comb-shaped filters to extract the phase information from low-frequency. The proposed algorithm is compared with the two major profilometry techniques, namely Fourier domain profilometry and sign...

A watermark is an invisible mark placed on an image that can be detected when the image is compared with the original. This mark is designed to identify both the source of an image as well as its intended recipient. The mark should be tolerant to reasonable quality lossy compression of the image using transform coding or vector quantization. Standa...

: A watermark is an invisible mark placed on an image that can be detected when the image is compared with the original. This mark is designed to identify both the source of an image as well as its intended recipient. The aims of this paper are to present an overview of watermarking techniques and to demonstrate a solution to one of the key problem...

Solder paste inspection, i.e. reconstruction of the 3D shape of the solder paste printed on surface mount technology component pads, is a major inspection task in the printed circuit board manufacturing process. We have investigated the use of machine vision methods based on structured light and phase measurement for on-line solder paste inspection...

A watermark is an invisible mark placed on an image that is designed to identify both the source of an image as well as its intended recipient. The authors present an overview of watermarking techniques and demonstrate a solution to one of the key problems in image watermarking, namely how to hide robust invisible labels inside grey scale or colour...

Reconstruction of 3D shape of the solder paste printed on SMT component pads is a major inspection task in the PCB manufacturing process. The paper reports on the use of phase proolometry for this inspection task. In phase proolometry a structured light pattern is projected onto the object and viewed by a camera. Since the imaged pattern is phase-m...

A watermark is all invisible mark placed on an image that can only be detected when the image is compared with the original. This mark is designed to identify both the source of a document as well as its intended recipient. This paper discusses various techniques for embedding such marks in grey scale and colour digital images. It begins specifying...

In EBT, any attempt to measure IC waveforms correctly using the SEM is hindered by two separate processes, namely; (1) signal distortion due to the finite spatial size of the electron beam and its temporal duration when pulsed and (2) the addition of noise. In this chapter, these processes are analyzed and an examination of techniques to counteract...

It is shown that when the primary input of an LMS (least mean square) adaptive noise canceler contains interference derived from a white source by means of an autoregressive process, a hybrid arrangement of adaptive IIR (infinite impulse response) and FIR (finite impulse response) filters can achieve improved performance. Convergence and stability...

The increase of the complexity of present ICs and the evolution of the technological design rules have enhanced the request of new techniques to evaluate the real behaviour of VLSI circuits. E-beam based techniques have shown to be a winning approach to examine the internal electrical and logical status of the circuit. The scanning electron beam mi...

VLSI validation task relieves on the use of E-beam equipment. However, the lack of a strong connection between the CAD (Computer Aided Design) world and the E-Beam world has somehow reduced the efficacy of this technique. The ADVICE System, is an enhanced CAD linked E-beam tester to locate automatically design errors on custom VLSI devices. The goa...

Necessary and sufficient conditions for the convergence of LMS (least-mean-squares) adaptive filters with Gaussian data have been established by L.L. Horowitz and K.D. Senne (1981), with the recent support of A. Feuer and E. Weinstein (1985). A feature of both of these studies is the necessity to investigate bounds on the roots of rather unwieldy c...

This paper summarizes some recent topics of electron beam testing in Japan: voltage contrast techniques, EB tester systems, measurement of microstructures, and automatic control of the electron optical column.

This paper presents an analysis of LMS-driven adaptive filters based on stochastic stability theory. Previous work in this area is critically reviewed, and the nature of convergence of sequences of random variables and of stochastic stability are discussed. In applying a theorem of Kushner to the LMS adaptive filter, it is found that the system is...

It is commonly stated that the least-mean-square (LMS) algorithm for adaptive filters is a stochastic version of the steepest descent (SD) optimisation technique, although little work on comparative studies has been reported. The present paper sets out a detailed theoretical and experimental comparison. Equations are derived for the directional var...

The paper describes the implementation and design of an adaptive digital filter. A brief introduction to the theory of adaptive filtering is first undertaken; this is followed by a description of the hardware used in the implementation. At this point, finite wordlength considerations are outlined. A consequence of these finite wordlength constraint...

In the paper, the regulation of nonminimum systems using a nonlinear minimum-variance control strategy is considered. The relationship between output variance and control limit of a saturating actuator is investigated. Both ultimatum simulation studies and an approximate analysis based on the statistical linearisation of the nonlinearity are presen...

The regulation of nonminimum systems using a nonlinear minimum-variance control strategy is considered. The relationship between output variance and control limit of a saturating actuator is investigated. Both ultimatum simulation studies and an approximate analysis based on the statistical linearisation of the nonlinearity are presented. The resul...

This paper presents an analysis of the constrained least squares filter and a feedback structure is derived which shows the noise cancelling properties of the filter. Using an identification algorithm, it is shown how the constrained least squares filter can be replaced by a finite impulse response filter which can be implemented on-line. The limit...

This paper presents an implementation of an adaptive digital filter. The hardware is outlined and the limitations of the design discussed. The effect of rounding on the filter characteristics is described. A method of improving filter performance, when using low adaptive gains, by means of the addition of a dither signal to the coefficient updates...

Practical limitations on a recently proposed technique for the identification of nonlinear systems using correlation analysis are explained. An analysis is presented which shows that it is not, in general, possible to identify discrete-time equivalents of the continuous linear subsystems in a system consisting of a linear system in cascade with a s...

This correspondence shows that independent necessary conditions and sufficient conditions for the asymptotic stability of two-dimensional discrete linear systems presented by Ahmed [1] can be readily obtained from previous results.

A large class of discrete multipass processes can be viewed as two-dimensional systems of the form proposed by Roesser. It is shown that the criterion for stability along the pass is equivalent to Shanks condition for two-dimensional b.i.b.o. stability. The interplay of ideas between the two disciplines should make possible the emergence of a coher...

Recent work on the use of discrete first-order approximate models of plant dynamics in multi-variable process control is extended to consider the effect on transient performance of nonhinearities, such as measurement quantisation or dead-zone at the implementation stage. Explicit upper bounds on the transient error induced by the nonlinearity are o...

The real parts of the invariant zeros of an mx system S (A,B,C) satisfying a partial symmetry condition can be bounded from above and below by the eigenvalues of the symmetric part of A. Where applicable the results provide a simple computational technique for assessing the minimum phase structure of the system.

Recent work on the use of discrete first-order approximate models of plant dynamics in multi-variable process control is extended to consider the effect on transient performance non-linearities such as measurement quantization or deadzone at the implement stage. Explicit upper bands on the transient error induced by the nonlinearity are obtained a...

Problems associated with the production of special steels during the melting and refining stages in the electric arc furnace are discussed. Three-phase models of an arc impedance and arc current controlled furnace are developed by combining the results of an identification study with analytically derived models. Current and impedance control strate...

The argon-oxygen decarburising process is an increasingly important method of stainless-steel manufacture. In the paper, a nonlinear dynamic model is presented which represents approximately the refining process. Finite-dimensional-optimisation techniques are used to calculate an optimal switched control, and infinite-dimensional-gradient methods a...

The commercial incentives to obtain improved control of the steelmaking process in the electric-arc furnace are presented, and the progress made in applying computer control is reviewed. The development of a mathematical model of the refining process is shown to be restricted by the complex metallurgical nature of the process and the deficiency of...

Problems associated with the production of special steels in the electric arc furnace are discussed. The production cycle is segmented into three stages consisting of scrap mix selection and load scheduling; power input control during the melting cycle; and refining control. Analysis of the production cycle as a three-stage process exposes the diff...

Techniques for control of divergence of the Kalman filter are considered. The application in practice of three decision-directed methods for divergence prevention is investigated. A critical study of the measures of filter quality and the control actions which these methods employ is presented and a new method is suggested for control of divergence...

In this paper, we present an investigation into the perception of source depth in interactive virtual auditory environments in the context of Higher Order Ambisonic (HOA) reproduction. In particular, we investigate the accuracy of soundfield reproduc-tion over virtual loudspeakers (headphone reproduction) with in-creasing Ambisonic order. Performan...